WO2014054627A1 - Steering control device - Google Patents

Steering control device Download PDF

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Publication number
WO2014054627A1
WO2014054627A1 PCT/JP2013/076679 JP2013076679W WO2014054627A1 WO 2014054627 A1 WO2014054627 A1 WO 2014054627A1 JP 2013076679 W JP2013076679 W JP 2013076679W WO 2014054627 A1 WO2014054627 A1 WO 2014054627A1
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WO
WIPO (PCT)
Prior art keywords
steering
reaction force
torque
angle
curvature
Prior art date
Application number
PCT/JP2013/076679
Other languages
French (fr)
Japanese (ja)
Inventor
裕也 武田
Original Assignee
日産自動車株式会社
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Filing date
Publication date
Application filed by 日産自動車株式会社 filed Critical 日産自動車株式会社
Priority to JP2014539755A priority Critical patent/JP5835499B2/en
Publication of WO2014054627A1 publication Critical patent/WO2014054627A1/en

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    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D6/00Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/008Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B62LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62DMOTOR VEHICLES; TRAILERS
    • B62D15/00Steering not otherwise provided for
    • B62D15/02Steering position indicators ; Steering position determination; Steering aids
    • B62D15/025Active steering aids, e.g. helping the driver by actively influencing the steering system after environment evaluation

Definitions

  • the present invention relates to a steering control device.
  • Patent Document 1 discloses a technique for reducing the steering reaction force applied to the steering wheel according to the self-aligning torque as the curvature increases with the aim of smooth passage on a curve.
  • the objective of this invention is providing the steering control apparatus which can reduce the discomfort given to a driver.
  • a larger offset amount is calculated as the curvature is larger, and a steering reaction force characteristic is set on a coordinate having the self-aligning torque and the steering reaction force as coordinate axes, and a larger steering reaction force as the self-aligning torque is larger. Then, on the coordinates, the steering reaction force characteristic is offset by an offset amount in the same sign direction as the self-aligning torque.
  • the steering reaction force can be changed while maintaining the steering reaction force characteristic, and the uncomfortable feeling given to the driver can be reduced.
  • FIG. 1 is a system diagram illustrating a vehicle steering system according to a first embodiment.
  • 3 is a control block diagram of a turning control unit 19.
  • FIG. 3 is a control block diagram of a steering reaction force control unit 20.
  • FIG. 4 is a control block diagram of a disturbance suppression command turning angle calculation unit 32.
  • FIG. 6 is a control block diagram of a repulsive force calculation unit 37 according to a yaw angle. It is a control block diagram of the repulsive force calculation unit 38 according to the lateral position. It is a figure which shows the control area
  • FIG. 6 It is a time chart which shows a yaw angle change when the vehicle which is driving
  • 6 is a time chart showing yaw angle change and lateral position change when lateral position F / B control is not performed when a vehicle traveling on a straight road on a highway receives continuous lateral wind.
  • 6 is a time chart showing a yaw angle change and a lateral position change when lateral position F / B control is performed when a vehicle traveling on a straight road on a highway receives continuous lateral wind.
  • 4 is a control block diagram of a lateral force offset unit 34.
  • FIG. 6 is a characteristic diagram showing a relationship between a steering angle of a steering wheel and a steering torque of a driver. By offsetting the steering reaction force characteristic representing the steering reaction torque according to the self-aligning torque in the same direction as the self-aligning torque, the characteristic indicating the relationship between the steering angle of the steering wheel and the steering torque of the driver has changed. It is a figure which shows a state.
  • 4 is a control block diagram of a steering reaction force torque offset unit 36.
  • FIG. FIG. 5 is a control block diagram of a reaction force calculation unit 39 corresponding to a departure allowance time.
  • FIG. 6 is a characteristic diagram showing a relationship between a steering angle of a steering wheel and a steering torque of a driver. The relationship between the steering angle of the steering wheel and the steering torque of the driver is shown by offsetting the steering reaction force characteristic representing the steering reaction force torque according to the self-aligning torque in the direction in which the absolute value of the steering reaction force torque increases. It is a figure which shows the state from which the characteristic changed.
  • FIG. 3 is a block diagram illustrating a control configuration in a limiter processing unit in a lateral force offset unit according to the first embodiment. It is the schematic showing the relationship between the last value and lateral value of lateral force offset amount in case steering torque arises on the opposite side of Example 1. 3 is a B value setting map according to the first embodiment. In the steering control apparatus of Example 1, it is the schematic showing the state at the time of the curve which has a comparatively big curvature continuing.
  • FIG. 25 is a time chart when the state shown in FIG. 24 has elapsed in the steering control device of the first embodiment.
  • Steering part 2 Steering part 3 Backup clutch 4 SBW controller 5FL, 5FR Front left and right wheels 6 Steering wheel 7 Column shaft 8 Reaction force motor 9 Steering angle sensor 11 Pinion shaft 12 Steering gear 13 Steering motor 14 Steering angle sensor 15 Rack gear 16 racks 17 Camera 18 Vehicle speed sensor 19 Steering control unit 19a Adder 20 Steering reaction force controller 20a subtractor 20b adder 20c adder 21 Video processor 22 Current driver 23 Current driver 24 Navigation system 31 Command turning angle calculator 32 Disturbance suppression command turning angle calculator 32a Yaw angle calculator 32b Curvature calculator 32c Horizontal position calculator 32d adder 32e Target yaw moment calculator 32f Target yaw acceleration calculator 32g target yaw rate calculator 32h Command turning angle calculator 32i limiter processor 33 Lateral force calculator 34 Lateral force offset 34a Curvature calculator 34b Upper / lower limiter 34c SAT gain calculator 34d multiplier 34e Limiter processing section 35 SAT calculator 36 Steering reaction torque offset part 36a Yaw angle calculator 36b
  • FIG. 1 is a system diagram illustrating a vehicle steering system according to the first embodiment.
  • the steering device according to the first embodiment mainly includes a steering unit 1, a steering unit 2, a backup clutch 3, and an SBW controller 4, a steering unit 1 that receives a steering input from a driver, and left and right front wheels (steered wheels) 5FL, 5FR.
  • a steer-by-wire (SBW) system in which the steering unit 2 that steers the vehicle is mechanically separated is employed.
  • the steering unit 1 includes a steering wheel 6, a column shaft 7, a reaction force motor 8, and a steering angle sensor 9.
  • the column shaft 7 rotates integrally with the steering wheel 6.
  • the reaction force motor 8 is, for example, a brushless motor, the output shaft of which is a coaxial motor coaxial with the column shaft 7, and outputs a steering reaction force torque to the column shaft 7 in response to a command from the SBW controller 4.
  • the steering angle sensor 9 detects the absolute rotation angle of the column shaft 7, that is, the steering angle of the steering wheel 6.
  • the steered portion 2 includes a pinion shaft 11, a steering gear 12, a steered motor 13, and a steered angle sensor 14.
  • the steering gear 12 is a rack and pinion type steering gear, and steers the front wheels 5L and 5R according to the rotation of the pinion shaft 11.
  • the steered motor 13 is, for example, a brushless motor, whose output shaft is connected to the rack gear 15 via a reduction gear (not shown), and steers the front wheels 5 to the rack 16 in response to a command from the SBW controller 4.
  • the steering torque is output.
  • the turning angle sensor 14 detects the absolute rotation angle of the turning motor 13.
  • the steered angle of the front wheels 5 can be detected from the rotational angle of the steered motor 13.
  • the backup clutch 3 is provided between the column shaft 7 of the steering unit 1 and the pinion shaft 11 of the steering unit 2, and mechanically separates the steering unit 1 and the steering unit 2 by release, and the steering unit 1 by fastening. And the steering unit 2 are mechanically connected.
  • the SBW controller 4 is input with the image of the traveling road ahead of the vehicle photographed by the camera 17 and the vehicle speed (vehicle speed) detected by the vehicle speed sensor 18.
  • the SBW controller 4 includes a steering control unit 19 that controls the steering angle of the front wheels 5FL and 5FR, and a steering reaction force control unit that controls the steering reaction force torque applied to the column shaft 7 (steering reaction force control means, controller). 20 and a video processing unit 21.
  • the turning control unit 19 generates a command turning angle based on each input information, and outputs the generated command turning angle to the current driver 22.
  • the current driver 22 controls the command current to the steered motor 13 by angle feedback that matches the actual steered angle detected by the steered angle sensor 14 with the commanded steered angle.
  • the steering reaction force control unit 20 generates a command steering reaction force torque based on each input information, and outputs the generated command steering reaction force torque to the current driver 23.
  • the current driver 23 controls the command current to the reaction force motor 8 by torque feedback that matches the actual steering reaction force torque estimated from the current value of the reaction force motor 8 with the command steering reaction force torque.
  • the video processing unit 21 recognizes the white lines (traveling line dividing lines) on the left and right of the traveling lane by image processing such as edge extraction from the image of the traveling path ahead of the host vehicle taken by the camera 17.
  • the SBW controller 4 engages the backup clutch 3 to mechanically connect the steering unit 1 and the steered unit 2 to move the rack 16 in the axial direction by steering the steering wheel 6. Make it possible. At this time, control equivalent to an electric power steering system that assists the steering force of the driver by the assist torque of the steering motor 13 may be performed.
  • a redundant system including a plurality of sensors, controllers, and motors may be used. Further, the steering control unit 19 and the steering reaction force control unit 20 may be separated.
  • Stability control performs two feedback (F / B) controls for the purpose of improving vehicle stability against disturbances (crosswind, road surface unevenness, dredging, road surface cant, etc.).
  • F / B two feedback
  • the steering angle is corrected according to the yaw angle, which is the angle between the white line and the direction of travel of the vehicle, and the yaw angle generated by the disturbance is reduced.
  • Lateral position F / B control The steering angle is corrected according to the distance to the white line (lateral position), and the lateral position change, which is the integrated value of the yaw angle caused by the disturbance, is reduced.
  • the corrected steering reduction control performs three reaction force offset controls for the purpose of improving the stability of the vehicle with respect to the driver's steering input.
  • Reaction force offset control according to the lateral position The steering reaction force characteristic according to the self-aligning torque is offset according to the lateral position in the direction in which the absolute value of the steering reaction force increases, and the driver crosses the steering angle neutral position. It is possible to prevent the sign of the steering torque from being reversed when corrective steering is performed.
  • Reaction force offset control according to the deviation margin time Offset the steering reaction force characteristic according to the self-aligning torque in the direction in which the absolute value of the steering reaction force increases according to the deviation margin time (time to reach the white line).
  • FIG. 2 is a control block diagram of the steering control unit 19.
  • the SBW command turning angle calculation unit 31 calculates the SBW command turning angle based on the steering angle and the vehicle speed.
  • the disturbance suppression command turning angle calculation unit 32 calculates a disturbance suppression command turning angle for correcting the SBW command turning angle in the stability control based on the vehicle speed and the white line information. Details of the disturbance suppression command turning angle calculation unit 32 will be described later.
  • the adder 19a outputs a value obtained by adding the SBW command turning angle and the disturbance suppression command turning angle to the current driver 22 as a final command turning angle.
  • FIG. 3 is a control block diagram of the steering reaction force control unit 20.
  • the lateral force calculation unit 33 refers to a steering angle-lateral force conversion map that represents the relationship between the steering angle for each vehicle speed and the tire lateral force in a conventional steering device that has been obtained in advance through experiments or the like based on the steering angle and the vehicle speed. To calculate the tire lateral force.
  • the larger the steering angle the greater the tire lateral force, and when the steering angle is small, the amount of change in the tire lateral force relative to the amount of change in the steering angle is greater than when the steering angle is large.
  • the tire has a characteristic that the tire lateral force decreases as the value increases.
  • the lateral force offset unit (offset means) 34 calculates a lateral force offset amount for offsetting the steering reaction force characteristic in the reaction force offset control according to the curvature based on the vehicle speed and the white line information. Details of the lateral force offset unit 34 will be described later.
  • the subtractor 20a subtracts the lateral force offset amount from the tire lateral force.
  • the SAT calculation unit 35 is a lateral force that represents the relationship between the tire lateral force and the steering reaction force torque in the conventional steering system, which is obtained in advance through experiments or the like based on the vehicle speed and the tire lateral force after offset based on the lateral force offset amount.
  • the steering reaction force torque generated by the tire lateral force is calculated with reference to the steering reaction force torque conversion map.
  • the tire lateral force-steering reaction torque conversion map shows that the larger the tire lateral force is, the larger the steering reaction torque becomes.
  • the amount of change in the steering reaction torque with respect to the amount of change in the tire lateral force is larger than when the tire lateral force is large.
  • the steering reaction torque decreases as the vehicle speed increases. This characteristic simulates the reaction force generated in the steering wheel by the self-aligning torque in which the wheel generated by the road surface reaction force returns to the straight traveling state in the conventional steering device.
  • the adder 20b adds the steering reaction force torque and the steering reaction force torque component (spring term, viscosity term, inertia term) corresponding to the steering characteristics.
  • the spring term is a component proportional to the steering angle, and is calculated by multiplying the steering angle by a predetermined gain.
  • the viscosity term is a component proportional to the steering angular velocity, and is calculated by multiplying the steering angular velocity by a predetermined gain.
  • the inertia term is a component proportional to the steering angular acceleration, and is calculated by multiplying the steering angular acceleration by a predetermined gain.
  • the steering reaction force torque offset unit 36 is a steering reaction force torque for offsetting the steering reaction force characteristic in the reaction force offset control according to the lateral position or the deviation margin time based on the vehicle speed and the image of the traveling road ahead of the host vehicle. Calculate the offset amount. Details of the steering reaction torque offset unit 36 will be described later.
  • the adder 20c outputs a value obtained by adding the steering reaction force torque after adding the steering reaction force torque component corresponding to the steering characteristics and the steering torque offset amount to the current driver 23 as a final command steering reaction force torque. .
  • FIG. 4 is a control block diagram of the disturbance suppression command turning angle calculation unit 32.
  • the yaw angle calculator 32a calculates a yaw angle that is an angle formed by the white line at the forward gazing point and the traveling direction of the host vehicle.
  • the yaw angle at the forward gazing point is an angle formed by the white line after a predetermined time (for example, 0.5 seconds) and the traveling direction of the vehicle.
  • the curvature calculation unit 32b calculates the curvature of the white line at the forward gazing point.
  • the lateral position calculation unit 32c calculates the distance to the white line at the front gazing point. Based on the yaw angle, the curvature, and the vehicle speed, the repulsive force calculation unit 37 corresponding to the yaw angle calculates the vehicle repulsive force for reducing the yaw angle generated by the disturbance in the yaw angle F / B control. Details of the repulsive force calculation unit 37 according to the yaw angle will be described later.
  • the repulsive force calculation unit 38 according to the lateral position is used to reduce lateral position changes caused by disturbances in lateral position F / B control. Calculate the repulsive force of the vehicle. Details of the repulsive force calculation unit 38 according to the lateral position will be described later.
  • the adder 32d adds the repulsive force according to the yaw angle and the repulsive force according to the lateral position, and calculates the lateral repulsive force.
  • the target yaw moment calculator 32e calculates a target yaw moment based on the lateral repulsive force, the wheel base (distance between the axles), the rear wheel axle weight, and the front wheel axle weight. Specifically, a value obtained by multiplying the lateral repulsive force by the ratio of the rear wheel axle weight to the vehicle weight (front wheel axle weight + rear wheel axle weight) and the wheel base is set as the target yaw moment.
  • the target yaw acceleration calculation unit 32f multiplies the target yaw moment by the yaw inertia moment coefficient to calculate the target yaw acceleration.
  • the target yaw rate calculation unit 32g calculates the target yaw rate by multiplying the target yaw acceleration by the vehicle head time.
  • the command turning angle calculation unit 32h calculates a disturbance suppression command turning angle ⁇ st * with reference to the following formula based on the target yaw rate ⁇ * , the wheel base WHEEL_BASE, the vehicle speed V, and the vehicle characteristic speed vCh.
  • the vehicle characteristic speed V ch is a parameter in the known “Ackermann equation” and represents the self-steering characteristic of the vehicle.
  • ⁇ st * ( ⁇ * ⁇ WHEEL_BASE ⁇ (1+ (V / vCh) 2 ) ⁇ 180) / (V ⁇ M_PI) M_PI is a predetermined coefficient.
  • the limiter processing unit 32i limits the maximum value of the disturbance suppression command turning angle ⁇ st * and the upper limit of the change rate.
  • the maximum value is in a play angle range (for example, 3 ° to the left and right) of the steering wheel 6 near the neutral position in a conventional steering device (the steering unit and the steering unit are mechanically connected).
  • the turning angle range of the front wheels 5FL and 5FR corresponding to the range of play at that time (for example, right and left 0.2 °).
  • FIG. 5 is a control block diagram of the repulsive force calculation unit 37 according to the yaw angle.
  • the upper / lower limiter 37a performs upper / lower limiter processing on the yaw angle.
  • the upper / lower limiter is greater than or equal to a predetermined value capable of suppressing disturbance, and A value that is less than a value that causes the vehicle to vibrate and a value that is generated by the steering of the driver (for example, 1 °), and 0 if the yaw angle is negative.
  • the yaw angle F / B gain multiplication unit 37b multiplies the yaw angle after the limiter process by the yaw angle F / B gain.
  • the yaw angle F / B gain is equal to or greater than a predetermined value that can ensure responsiveness while avoiding insufficient control amount, and less than the value at which the vehicle vibrates and the driver feels the neutral deviation between the steering angle and the turning angle.
  • the vehicle speed correction gain multiplication unit 37c multiplies the vehicle speed by the vehicle speed correction gain.
  • the vehicle speed correction gain has a maximum value in the range of 0 to 70 km / h, a gradual decrease in the range of 70 to 130 km / h, and a minimum value (0) in the range of 130 km / h or higher.
  • the curvature correction gain multiplication unit 37d multiplies the curvature by the curvature correction gain.
  • the curvature correction gain has a characteristic that decreases as the curvature increases, and an upper limit and a lower limit (0) are set.
  • the multiplier 37e multiplies the outputs of the yaw angle F / B gain multiplication unit 37b, the vehicle speed correction gain multiplication unit 37c, and the curvature correction gain multiplication unit 37d to obtain a repulsive force according to the yaw angle.
  • FIG. 6 is a control block diagram of the repulsive force calculation unit 38 according to the lateral position.
  • the subtractor 38a obtains the lateral position deviation by subtracting the distance from the preset lateral position threshold (for example, 90 cm) to the white line at the front gazing point.
  • the upper / lower limiter 38b performs upper / lower limiter processing on the lateral position deviation.
  • the upper / lower limiter takes a predetermined positive value when the lateral position deviation is a positive value, and is 0 when the lateral position deviation is a negative value.
  • the distance correction gain multiplication unit 38c multiplies the distance to the white line at the front gaze point by the distance correction gain.
  • the distance correction gain takes a maximum value when the distance to the white line is equal to or smaller than a predetermined value, and when the distance exceeds the predetermined value, the distance correction gain has a characteristic that becomes smaller as the distance becomes longer, and a lower limit is set.
  • the horizontal position F / B gain multiplication unit 38d multiplies the distance to the white line corrected by the distance correction gain multiplication unit 38c by the horizontal position F / B gain.
  • the lateral position F / B gain is set to a value that is equal to or greater than a predetermined value that can ensure responsiveness while avoiding a shortage of control amount, and that is less than a value that makes the vehicle vibrate and a value that the driver feels neutral deviation.
  • a value smaller than the yaw angle F / B gain of the B gain calculation unit 37b is set.
  • the vehicle speed correction gain multiplication unit 38e multiplies the vehicle speed by the vehicle speed correction gain.
  • the vehicle speed correction gain has a maximum value in the range of 0 to 70 km / h, a gradual decrease in the range of 70 to 130 km / h, and a minimum value (0) in the range of 130 km / h or higher.
  • the curvature correction gain multiplication unit 38f multiplies the curvature by the curvature correction gain.
  • the curvature correction gain has a characteristic that decreases as the curvature increases, and an upper limit and a lower limit (0) are set.
  • the multiplier 38g multiplies each output of the lateral position F / B gain multiplication unit 38d, the vehicle speed correction gain multiplication unit 38e, and the curvature correction gain multiplication unit 38f to obtain a repulsive force according to the lateral position.
  • the yaw angle F / B control for reducing the yaw angle caused by the disturbance and the lateral position F / B control for reducing the lateral position change that is an integral value of the yaw angle caused by the disturbance.
  • the yaw angle F / B control is performed regardless of the lateral position when the yaw angle occurs.
  • the lateral position F / B control is performed when the distance to the white line is equal to or less than the predetermined lateral position threshold (90 cm). carry out. That is, the vicinity of the center of the traveling lane is a dead zone for lateral position F / B control.
  • the control area of both F / B controls is shown in FIG. ⁇ is the yaw angle.
  • FIG. 8 is a time chart showing a change in yaw angle when a vehicle traveling on a straight road on a highway receives a single crosswind, and it is assumed that the vehicle is traveling near the center of the traveling lane.
  • the yaw angle F / B control calculates the repulsive force according to the yaw angle, finds the disturbance suppression command turning angle to obtain the repulsive force, The SBW command turning angle based on the steering angle and the vehicle speed is corrected.
  • the yaw angle is zero because the direction of the white line and the traveling direction of the vehicle coincide with each other, particularly on a straight road.
  • the generated yaw angle is considered to be due to disturbance, and by reducing the yaw angle, the stability of the vehicle against disturbance can be improved particularly during straight running.
  • the driver's correction steering amount can be reduced.
  • 5R can be controlled independently of each other, and the command turning angle is obtained by adding the SBW command turning angle according to the steering angle and the vehicle speed and the disturbance suppression command turning angle according to the yaw angle. Based on this, the steering angle of the front wheels 5L, 5R is controlled, while the tire lateral force is estimated based on the steering angle and the vehicle speed, and the steering reaction force is determined based on the commanded steering reaction force according to the estimated tire lateral force and the vehicle speed. Control power. That is, since the turning angle corresponding to the disturbance suppression is directly given to the front wheels 5L and 5R, it is not necessary to provide a steering reaction force component that prompts the steering for disturbance suppression.
  • the fluctuation of the tire lateral force caused by the steering for suppressing the disturbance is not reflected in the steering reaction force, so the driver feels uncomfortable. Can be reduced.
  • a tire lateral force is estimated from a rack axial force and a turning angle detected by a sensor, and a steering reaction force corresponding to the estimated tire lateral force is applied. For this reason, the fluctuation of the tire lateral force generated by the steering for suppressing the disturbance is always reflected in the steering reaction force, which makes the driver feel uncomfortable.
  • the uncomfortable feeling given to the driver can be reduced.
  • the disturbance suppression command turning angle is changed to conventional.
  • the steering wheel 6 is in the play angle range near the steering angle neutral position (left and right 3 °)
  • the generation of the yaw angle due to disturbance is more conspicuous when traveling straight than when turning, and the steering angle is located near the steering angle neutral position when traveling straight.
  • the correction of the turning angle by the yaw angle F / B control is almost always performed near the steering angle neutral position, so the steering angle and the turning angle associated with the provision of the disturbance suppression command turning angle By suppressing the amount of neutral deviation within the range of steering play, it is possible to suppress a sense of incongruity associated with neutral deviation.
  • the disturbance suppression command turning angle is limited to a range of 0.2 ° to the left and right, the driver can change the traveling direction of the vehicle to a desired direction by the steering input even during the stability control.
  • the amount of correction of the turning angle based on the disturbance suppression command turning angle is very small with respect to the amount of change in the turning angle caused by the driver's steering input. Can be realized.
  • lane departure prevention control that gives the vehicle a yaw moment that avoids departure when a vehicle traveling lane departure tendency is detected, or the vehicle travels near the center of the traveling lane.
  • Lane keeping control for imparting a yaw moment to a vehicle is known.
  • the lane departure prevention control is a control having a threshold for control intervention, and the control does not operate in the vicinity of the center of the traveling lane, so the stability of the vehicle against disturbance cannot be ensured. Further, even when the driver wants to bring the vehicle to the end of the traveling lane, control intervention is performed according to the threshold value, which causes trouble for the driver.
  • the control has a target position (target line), and although the stability of the vehicle against disturbance can be ensured, a line deviating from the target line cannot be driven.
  • the control is canceled by determining that the steering wheel is released, so the driver must always grip the steering wheel with a certain force or more, and the driver's steering load is reduced. large.
  • the yaw angle F / B control of the first embodiment does not have a threshold value for control intervention, it is possible to always ensure stability against disturbance by seamless control.
  • the driver since it does not have a target position, the driver can drive the vehicle along a favorite line. In addition, even when the steering wheel 6 is held lightly, the control is not released, and the steering load on the driver can be reduced.
  • FIG. 9 is a time chart showing the yaw angle change and the lateral position change when the lateral position F / B control is not performed when the vehicle traveling on the straight road of the expressway receives continuous lateral wind. Is driving near the center of the driving lane.
  • the yaw angle F / B control reduces the yaw angle, and when the yaw angle is zero, the turning angle is not corrected, so the lateral position change, which is the integrated value of the yaw angle caused by the disturbance, is directly detected.
  • the yaw angle multiplied by the yaw angle F / B gain is limited to the upper limit (1 °) or less by the upper / lower limiter 37a.
  • the repulsive force according to the yaw angle is a repulsive force corresponding to a yaw angle smaller than the actual yaw angle. From this point, the lateral flow of the vehicle can be effectively suppressed only by the yaw angle F / B control. Proves difficult.
  • FIG. 10 is a time chart showing changes in yaw angle and lateral position when lateral position F / B control is performed when a vehicle traveling on a straight road on a highway receives continuous lateral wind.
  • position F / B control when the vehicle running near the center of the lane is subjected to continuous crosswinds and flows laterally, and the distance to the white line is less than the lateral position threshold, the lateral position changes ( ⁇ yaw angle integral value). The corresponding repulsive force is calculated.
  • the disturbance suppression command turning angle calculation unit 32 calculates the disturbance suppression command turning angle based on the lateral repulsive force that is the sum of the repulsive force according to the lateral position and the repulsive force according to the yaw angle. Correct the corners. That is, in the lateral position F / B control, the SBW command turning angle is corrected by the disturbance suppression command turning angle according to the lateral position, so it is possible to directly reduce the lateral position change due to steady disturbance. Yes, the lateral flow of the vehicle can be suppressed. In other words, the travel position of the vehicle that performs the yaw angle F / B control can be returned to the vicinity of the center of the travel lane, which is the dead zone of the lateral position F / B control.
  • the stability control of the first embodiment reduces the yaw angle change due to the transient disturbance by the yaw angle F / B control, and the yaw angle integral value (lateral position change) due to the steady disturbance is changed to the horizontal position.
  • Reduction by F / B control can improve both vehicle stability against transient and steady disturbances.
  • the stability control of the first embodiment is such that the driver is not aware of the vehicle behavior caused by the control (giving the disturbance suppression command turning angle) and does not disturb the vehicle behavior change caused by the driver's steering. This is possible without limiting the driver to be aware that the stability control is being performed because the change in the self-aligning torque caused by the control is not reflected in the steering reaction force.
  • the lateral position F / B control the lateral position F / B gain for obtaining the repulsive force according to the lateral position is set to a value smaller than the yaw angle F / B gain.
  • the yaw angle F / B control is required to converge the yaw angle before the driver feels a change in yaw angle due to a transient disturbance.
  • B control is required to stop increasing the lateral position change, and it takes time for the lateral position to change due to the accumulation of the yaw angle integral value. Is not necessary.
  • the control amount fluctuates greatly depending on the magnitude of the disturbance, giving the driver a sense of incongruity.
  • FIG. 11 is a control block diagram of the lateral force offset unit 34.
  • the curvature calculation unit (curvature detection means, sensor) 34a calculates the curvature of the white line at the front gazing point.
  • the upper / lower limiter 34b performs upper / lower limiter processing on the vehicle speed.
  • the SAT gain calculation unit 34c calculates the SAT gain according to the vehicle speed based on the vehicle speed after the limiter process.
  • the SAT gain has a characteristic that increases as the vehicle speed increases, and an upper limit is set.
  • the multiplier 34d obtains the lateral force offset amount by multiplying the SAT gain by the curvature.
  • the limiter processing unit 34e limits the maximum value of the lateral force offset amount and the upper limit of the change rate. For example, the maximum value is 1,000 N, and the upper limit of the change rate is 600 N / s. The limitation on the lateral force offset amount in the limiter processing unit 34e will be described later in detail.
  • reaction force offset control according to curvature obtains a larger lateral force offset amount as the curvature of the white line is larger, and subtracts it from the tire lateral force.
  • the steering reaction force torque corresponding to the tire lateral force calculated by the SAT calculation unit 35 that is, the steering reaction force characteristic indicating the steering reaction force torque corresponding to the self-aligning torque, is shown in FIG.
  • the self-aligning torque is offset in the same sign direction. Note that FIG. 12 shows the case of the right curve, and the case of the left curve is offset in the opposite direction to FIG.
  • a steering reaction force characteristic that simulates the steering reaction force according to the self-aligning torque in the conventional steering device is set, and the steering reaction force A steering reaction force is applied to the steering wheel based on the characteristics.
  • the relationship between the steering angle of the steering wheel and the steering torque of the driver is a characteristic A as shown in FIG. That is, the larger the absolute value of the steering angle, the larger the absolute value of the steering torque.
  • the absolute value of the steering angle is small, the amount of change of the steering torque with respect to the amount of change of the steering angle becomes larger than when the absolute value of the steering angle is large.
  • the steering reaction force characteristic representing the steering reaction force torque corresponding to the self-aligning torque becomes the same sign direction as the self-aligning torque as the curvature of the white line is larger.
  • the characteristic representing the relationship between the steering angle and the steering torque is offset in the same sign direction as the steering angle, and changes from characteristic A to characteristic B.
  • the driver reduces the fixed steering torque to T 4, the reduction amount [Delta] T 3-4 of steering holding torque Figure
  • the decrease amount ⁇ 1-4 of the steering angle is smaller than the decrease amount ⁇ 1-2 of the prior art.
  • the greater the curvature of the curve the smaller the fluctuation of the steering angle with respect to the change in the steering torque and the lower the sensitivity of the vehicle to the steering torque, so that the behavior change of the vehicle becomes gradual and the course correction by the driver is facilitated. be able to.
  • the steering torque T 3 ( ⁇ T 1 ) for maintaining the steering angle ⁇ 1 can be made smaller than that of the prior art, the driver's steering burden during turning can be reduced.
  • FIG. 15 is a control block diagram of the steering reaction force torque offset unit 36.
  • the yaw angle calculator 36a calculates the yaw angle at the forward gazing point. By calculating the yaw angle based on the image of the travel path taken by the camera 17, the yaw angle can be detected easily and with high accuracy.
  • the horizontal position calculation unit 36b calculates a horizontal position with respect to the left and right white lines at the forward gazing point and a horizontal position with respect to the left and right white lines at the current position.
  • the horizontal position calculation unit 36b switches the horizontal position with respect to the left and right white lines at the current position. That is, the horizontal position with respect to the left white line before reaching the white line is set as the horizontal position with respect to the right white line after reaching the white line, and the horizontal position with respect to the right white line before reaching the white line is set as the horizontal position with respect to the left white line after reaching the white line.
  • the value W 2 / W 1 obtained by dividing the lane width W 2 of the lane after the lane change by the lane width W 1 of the lane before the lane change is replaced.
  • the horizontal position is corrected by multiplying the horizontal position.
  • the lane width information of each traveling lane is acquired from the navigation system 24.
  • the reaction force calculation unit 39 corresponding to the departure allowance time calculates the reaction force corresponding to the departure allowance time based on the vehicle speed, the yaw angle, and the lateral position with respect to the left and right white lines at the front gazing point. Details of the reaction force calculation unit 39 according to the departure allowance time will be described later.
  • the reaction force calculation unit 40 according to the lateral position calculates a reaction force according to the lateral position based on the lateral position with respect to the left and right white lines at the current position. Details of the reaction force calculation unit 40 according to the lateral position will be described later.
  • the reaction force selection unit 36c selects, as the steering reaction force torque offset amount, the larger absolute value among the reaction force according to the departure allowance time and the reaction force according to the lateral position.
  • the limiter processing unit 36d limits the maximum value of the steering reaction force torque offset amount and the upper limit of the change rate. For example, the maximum value is 2 Nm, and the upper limit of the change rate is 10 Nm / s.
  • FIG. 16 is a control block diagram of the reaction force calculation unit 39 according to the departure allowance time.
  • the multiplier 39a obtains the lateral speed of the vehicle by multiplying the yaw angle by the vehicle speed.
  • the divider 39b divides the lateral position with respect to the left white line at the forward gazing point by the lateral speed to obtain a deviation margin time with respect to the left white line.
  • the divider 39c divides the lateral position with respect to the right white line at the forward gazing point by the lateral speed to obtain a deviation margin time with respect to the right white line.
  • the deviation margin time selection unit 39d selects the shorter of the deviation margin times for the left and right white lines as the deviation margin time.
  • the reaction force calculator 39e according to the departure allowance time calculates a reaction force according to the departure allowance time based on the departure allowance time.
  • the reaction force according to the deviation margin time is inversely proportional to the deviation margin time (proportional to the reciprocal of the deviation margin time), and has a characteristic of almost zero after 3 seconds.
  • FIG. 17 is a control block diagram of the reaction force calculation unit 40 according to the lateral position.
  • the subtractor 40a obtains a lateral position deviation with respect to the left lane by subtracting the lateral position with respect to the left lane from a preset target left lateral position (for example, 90 cm).
  • the subtractor 40b subtracts the lateral position with respect to the right lane from a preset target right lateral position (for example, 90 cm) to obtain a lateral position deviation with respect to the right lane.
  • the lateral position deviation selection unit 40c selects the larger one of the lateral position deviations with respect to the left and right lanes as the lateral position deviation.
  • the reaction force calculation unit 40d according to the lateral position deviation calculates a reaction force according to the lateral position based on the lateral position deviation.
  • the reaction force according to the lateral position has a characteristic that increases as the lateral position deviation increases, and an upper limit is set.
  • reaction force offset control action according to lateral position In the reaction force offset control according to the lateral position, the reaction force according to the lateral position is added to the steering reaction force torque as a steering reaction force torque offset amount.
  • the steering reaction force characteristic representing the steering reaction force torque corresponding to the self-aligning torque is offset in a direction in which the absolute value of the steering reaction force torque increases as the distance to the white line decreases, as shown in FIG.
  • the FIG. 18 shows a case where the vehicle is close to the right lane. When the vehicle is close to the left lane, the vehicle is offset in the opposite direction to FIG.
  • the driving position of the vehicle is shifted to the right side due to the driver's unexpected increase in the right direction, and then the driver returns the driving position to the vicinity of the center of the driving lane by correction steering.
  • the steering angle and steering torque when the driver performs an unexpected operation are set as the position of point P 1 on the characteristic A in FIG.
  • the characteristic A is a characteristic representing the relationship between the steering angle and the steering torque when the steering reaction force characteristic simulating a conventional steering device is set, as in FIG.
  • the steering reaction force torque according to the self-aligning torque is increased in the direction in which the absolute value of the steering reaction force torque increases as the distance to the white line is shorter.
  • the characteristic representing the relationship between the steering angle and the steering torque by the offset is offset from the characteristic A as the distance to the white line becomes shorter as the absolute value of the steering torque is increased as shown in FIG. Changes continuously to C.
  • the steering wheel 6 is gradually returned to the steering angle neutral position (point P 1 ⁇ point P 2 ), It is possible to prevent the vehicle travel position from shifting to the right side due to the driver's unexpected increase operation.
  • the steering angle and the steering torque move from the point P 1 to the point P 3 .
  • the steering torque neutral position is offset from the steering angle neutral position to the additional side, so the steering torque neutral position is increased when the steering angle is increased from the steering angle neutral position.
  • the sign of the steering torque is not reversed until the position is reached. Therefore, the driver can control the turning angle of the front wheels 5L and 5R only by reducing the steering torque and stopping the rotation of the steering wheel 6 when the steering wheel 6 reaches the target angle.
  • the reaction force offset control according to the lateral position of the first embodiment can facilitate the driver's correction steering because the direction in which the driver controls the force is difficult to switch. As a result, the travel position of the vehicle is less likely to overshoot, and the correction steering amount can be reduced.
  • the offset amount is increased as the distance to the white line is shorter. Therefore, the steering torque neutral position is the steering angle neutral position as the distance to the white line is shorter. Is offset further away from When the driver performs corrective steering to return the vehicle travel position to the vicinity of the center of the travel lane, the closer the white line is, the greater the amount of additional operation from the steering angle neutral position is required. At this time, if the offset amount of the steering torque neutral position with respect to the steering angle neutral position is small, the steering torque may exceed the neutral position and the sign of the steering torque may be reversed before the steering wheel reaches the target angle. Therefore, it is possible to suppress the steering torque from exceeding the neutral position by increasing the offset amount as the distance to the white line is shorter.
  • the lateral position calculation unit 36b switches the lateral position with respect to the left and right white lines at the current position when the host vehicle reaches the white line.
  • the host vehicle is more likely to return to the vicinity of the center of the travel lane by increasing the steering reaction force as the host vehicle is further away from the vicinity of the center of the travel lane.
  • the yaw angle integral value (lateral position change) is regarded as a disturbance, and the steering reaction force is controlled so as to guide the vehicle in a direction in which the yaw angle integral value disappears. For this reason, when a lane change is performed, it is necessary to reset the yaw angle integral value.
  • the steering reaction force for returning the vehicle to the vicinity of the center of the traveling lane before the lane change continues to act even after the lane change, and the driver's operation is hindered. Note that the vehicle cannot be guided near the center of the travel lane after the lane change by simply setting the integral value to zero.
  • the vehicle when the vehicle reaches the white line, it can be regarded as a driver's intentional operation. In this case, the lateral position with respect to the left and right white lines at the current position is switched. In order to guide the vehicle to the center of the lane after the lane change by switching the position where the vehicle is guided from the center of the lane before the lane change to the center of the lane after the lane change.
  • the steering reaction force can be generated.
  • reaction force offset control action according to deviation margin time In the reaction force offset control according to the departure allowance time, the reaction force according to the departure allowance time is added to the steering reaction force torque as the steering reaction force torque offset amount.
  • the steering reaction force characteristic representing the steering reaction force torque corresponding to the self-aligning torque is offset in a direction in which the absolute value of the steering reaction force torque increases as the deviation margin time decreases, as shown in FIG.
  • the FIG. 18 shows a case where the vehicle is close to the right lane. When the vehicle is close to the left lane, the vehicle is offset in the opposite direction to FIG.
  • the characteristic representing the relationship between the steering angle and the steering torque is offset in the direction in which the absolute value of the steering torque increases as shown in FIG. 20, and from characteristic A to characteristic C as the deviation margin time becomes shorter. And change continuously.
  • the steering angle neutral position point P 1 ⁇ point P 2
  • the steering angle and the steering torque move from the point P 1 to the point P 3 .
  • the steering torque neutral position is offset from the steering angle neutral position to the additional side, so the steering torque neutral position is increased when the steering angle is increased from the steering angle neutral position.
  • the sign of the steering torque is not reversed until the position is reached. Therefore, the driver can control the turning angle of the front wheels 5L and 5R only by reducing the steering torque and stopping the rotation of the steering wheel 6 when the steering wheel 6 reaches the target angle. That is, the reaction force offset control according to the departure allowance time according to the first embodiment can facilitate the driver's correction steering because the direction in which the driver controls the force is difficult to switch. As a result, the travel position of the vehicle is less likely to overshoot, and the correction steering amount can be reduced.
  • the offset amount is increased as the departure allowance time is shorter. Therefore, the steering torque neutral position is changed from the steering angle neutral position as the departure allowance time is shorter. Offset to a more distant position.
  • the driver performs corrective steering to return the vehicle travel position to near the center of the travel lane, the shorter the deviation margin time, the closer to the white line, and the closer to the white line, the greater the amount of operation to increase from the steering angle neutral position.
  • the offset amount of the steering torque neutral position with respect to the steering angle neutral position is small, the steering torque may exceed the neutral position and the sign of the steering torque may be reversed before the steering wheel reaches the target angle. Therefore, it is possible to suppress the steering torque from exceeding the neutral position by increasing the offset amount as the distance to the white line is shorter.
  • the steering reaction force torque offset unit 36 selects the reaction force corresponding to the deviation margin time and the reaction force corresponding to the lateral position having the larger absolute value as the steering reaction force torque offset amount.
  • the adder 20c adds the steering reaction torque offset amount to the steering reaction torque.
  • the steering reaction force characteristic is offset in a direction in which the absolute value of the steering reaction force torque is increased in accordance with the departure allowance time or the lateral position.
  • the reaction force offset control according to the departure allowance time when the vehicle and the white line are parallel, that is, when the yaw angle is zero, the reaction force according to the departure allowance time is zero.
  • reaction force offset control according to the horizontal position
  • a reaction force is generated in proportion to the distance to the white line, so a larger reaction force as the distance to the white line becomes shorter. And the vehicle can be easily returned to the vicinity of the center of the traveling lane.
  • reaction force offset control according to the lateral position when the vehicle is near the center of the traveling lane, the reaction force according to the lateral position is zero. For this reason, even in the vicinity of the center of the traveling lane, when the yaw angle is large and the vehicle speed is high, it is difficult to increase the steering reaction force with good response while reaching the white line in a short time.
  • reaction force offset control according to the departure allowance time a reaction force (reaction force according to the departure allowance time) is generated according to the departure allowance time, and the reaction force has a departure allowance time of 3 seconds.
  • the steering reaction force can be increased with good response to suppress lane departure. Therefore, by using the reaction force offset control according to the departure allowance time and the reaction force offset control according to the lateral position, it is possible to effectively deviate from the lane while giving a stable reaction force according to the distance to the white line. Can be suppressed. At this time, the optimum steering reaction force that is always required can be applied by using the reaction force corresponding to the departure allowance time and the reaction force corresponding to the lateral position having the larger absolute value.
  • FIG. 21 is a block diagram illustrating a control configuration in the limiter processing unit in the lateral force offset unit according to the first embodiment.
  • the limiter processing unit 34e determines whether or not the curvature is equal to or greater than a predetermined curvature set in advance. If the curvature is less than the predetermined curvature (a road composed of a substantially straight line or a very gentle curve), the limiter processing unit 34e is offset from the C value setting unit 346.
  • the steering torque estimation unit 342 estimates the steering torque with respect to the driver's curve direction based on the steering angle and the reaction force motor torque.
  • the estimated steering torque is output to the B value setting unit 343 and the latch flag determination unit 345.
  • the A value setting unit 342 determines whether or not the steering angle detected by the steering angle sensor 9 is steered by a predetermined value or more in a direction opposite to the curve direction (curvature direction) recognized by the camera 17, If it is less than the predetermined value, A1 is set as the A value, and if it is greater than the predetermined value, A2 is set as the A value.
  • the lateral force offset amount is more positively limited to reflect the driver's steering torque.
  • the B value setting unit 343 is a steering torque sensitivity gain that is set based on the magnitude of the steering torque in the direction opposite to the curve direction recognized by the camera 17, and by multiplying the A value, the driver's steering intention Sets the lateral force offset amount based on.
  • the C value setting unit 344 calculates the C value, which is an offset gain, from the following equation using the A value set by the A value setting unit 342 and the B value set by the B value setting unit 343.
  • C (1-A) + A ⁇ B
  • a value 0.75
  • the value of A ⁇ B changes in the range of 0.75 to 0. Therefore, the offset gain C changes in the range of 1 to 0.25.
  • the A value is set as the basic ratio of the offset amount that should be changed in response to the steering torque in the opposite direction. In this case, 75% of the offset amount is in the opposite direction. Sensitive to steering torque. In other words, 25% of the offset amount is secured regardless of the magnitude of the steering torque in the opposite direction.
  • the B value becomes smaller than 1 and A ⁇ B decreases, so the C value gradually decreases from 1 toward 0.25.
  • the latch flag determination unit 345 the curve direction recognized by the camera 17 based on the curvature and the steering torque estimated by the steering torque estimation unit 341 coincides with the direction of the steering torque, and a steering torque greater than a predetermined value is applied. If it matches and is equal to or greater than a predetermined value, the latch flag is set to 1, and flag information is output to the final limiter 347.
  • the final limiter 347 determines the final C value, multiplies the previous or current lateral force offset amount by the determined C value, and outputs the final lateral force offset amount.
  • specific processing performed in the final limiter 347 will be described.
  • C 1 set by the C value setting unit 346 is selected. Then, the lateral force offset amount in the current control cycle is multiplied by the C value as usual, and the lateral force offset amount in the current control cycle is output as the final control amount.
  • FIG. 22 is a schematic diagram illustrating the relationship between the previous value and the current value of the lateral force offset amount when the steering torque is generated on the opposite side of the first embodiment. As shown in FIG. 22, since the C value is set to a value less than 1, the lateral force offset amount is set in a range not exceeding the previous value and in accordance with the magnitude of the steering torque to the opposite side. can do.
  • FIG. 24 is a schematic diagram showing a state when curves having a relatively large curvature continue in the steering control device of the first embodiment.
  • FIG. 25 is a time chart when the state shown in FIG. 24 has elapsed in the steering control device of the first embodiment.
  • the road surface changes in a scene where a curve having a relatively large curvature continues or in a high-speed traveling state.
  • white line recognition does not catch up and there is a deviation from vehicle behavior, that is, white line recognition is delayed.
  • the driver visually recognizes the road shape and performs steering, and the driver recognition is faster than the recognition by the camera 17, so it may be difficult to assist the operation based on the driver recognition by the camera recognition. is there.
  • the driver recognition and the camera recognition are matched to some extent, and even if the appropriate steering assist is made, if the camera recognition is delayed for the next curve, It is assumed that the curve direction recognized by the driver is opposite to the curve direction recognized by the camera 17. At this time, if the driver has already started steering in anticipation of the next curve situation, the curvature of the curve recognized on the camera 17 side is the opposite side, so if the lateral force offset amount remains set, the driver will When steering to the side, an extremely large reaction force is applied, which may hinder steering, which makes the driver feel uncomfortable.
  • the lateral force offset amount is set according to the opposite steering torque.
  • the lateral force offset amount is not particularly limited, and the latch flag is set to 1. It is set. Then, as shown in the zone (2), the camera 17 side does not recognize that the curve direction has been reversed yet, and calculates the lateral force offset amount in a state where it is recognized as the right curve. On the other hand, the driver steers the steering wheel 6 to the opposite side while being aware of the state of the next curve. Then, the latch flag is reset to 0.
  • the lateral force offset amount is set on the right side, when steering to the left side, the steering reaction force becomes very large, making it difficult for the driver to steer to the opposite side. In order to avoid this phenomenon, the C value is set according to the magnitude of the opposite side steering torque, and the lateral force offset amount is reduced. As a result, the steering torque on the opposite side is suppressed, so that the driver can steer to the opposite side.
  • the steering angle of the driver exceeds a predetermined value, it can be determined that the intention of steering to the opposite side is certain, so the A value is switched to A2, which is larger than A1, and a smaller C value is calculated. . As a result, the lateral force offset amount becomes a smaller value, and the uncomfortable feeling can be further reduced.
  • Example 1 has the following effects.
  • Steering unit 2 that steers left and right front wheels 5FL and 5FR (steering wheels) and steering unit 1 that is mechanically separated and receives steering input from the driver, and coordinates that use self-aligning torque and steering reaction force as coordinate axes
  • a steering reaction force characteristic that sets a steering reaction force that becomes a larger steering reaction force as the self-aligning torque is larger, and applies a steering reaction force to the steering unit 1 based on the steering reaction force characteristic
  • a curvature calculation unit 34a that detects the curvature of the white line, and a lateral force that calculates a larger offset amount as the detected curvature is larger and offsets the steering reaction force characteristic on the coordinates in the same sign direction as the self-aligning torque by the offset amount
  • An offset unit 34 offset unit
  • a steering torque estimation unit 342 opposite side steering torque detection unit
  • the offset amount reducing means is large steering torque on the opposite side (the offset amount reducing means). That is, even when the lateral force offset amount is calculated with a delay in recognition of the camera 17, the curvature recognized by the camera 17 is steered toward the curve direction recognized by the driver. In the state where the steering torque on the side opposite to the curve direction is generated, the lateral reaction offset amount can be reduced to reduce the steering reaction force, and a large reaction force is generated when the driver steers to the opposite side. A sense of incongruity caused by the occurrence can be avoided.
  • An A value setting unit 342 (opposite steering angle determination means) is provided for determining whether or not the steering angle is steered beyond a predetermined steering angle on the side opposite to the curve direction of the curvature detected by the camera 17.
  • the limiter 347 greatly reduces the lateral force offset amount by setting A2 larger than A1 set when the steering angle is steered beyond the predetermined steering angle. Therefore, when the driver's steering intention is clear, the driver's uncomfortable feeling can be reduced by further reducing the lateral force offset amount.
  • the lateral force offset amount can be reduced to reduce the steering reaction force, and a large reaction force is generated when the driver steers to the opposite side. A sense of incongruity caused by the occurrence can be avoided.
  • a steering reaction force characteristic is set, which becomes a larger steering reaction force as the self-aligning torque is larger, and based on the steering reaction force characteristic,
  • the steering reaction force characteristic on the coordinates is offset in the same sign direction as the self-aligning torque.
  • SBW controller 4 that reduces the lateral force offset amount as the steering torque on the side opposite to the curve direction of the curvature detected by the camera 17 increases. Equipped with. That is, even when the lateral force offset amount is calculated with a delay in recognition of the camera 17, the curvature recognized by the camera 17 is steered toward the curve direction recognized by the driver. In the state where the steering torque on the side opposite to the curve direction is generated, the lateral reaction offset amount can be reduced to reduce the steering reaction force, and a large reaction force is generated when the driver steers to the opposite side. A sense of incongruity caused by the occurrence can be avoided.

Abstract

The present invention comprises: a steering unit (1) which receives steering input from a driver, said input being mechanically detached from a turning unit (2) which turns a left and a right front wheel (5FL, 5FR) (turning wheels); a steering reaction force control unit (20) which sets a steering reaction force characteristic to coordinates, of which the coordinate axes are self-aligning torque and the steering reaction force, so that the greater the self-aligning torque, the greater the steering reaction force, and said control unit applies the steering reaction force to the steering unit (1) on the basis of the steering reaction force characteristic; a curvature calculation unit (34a) which calculates curvature of a white line; a lateral force offset unit (34) (offset means) which calculates an offset amount that is greater the greater the detected curvature, and which offsets the steering reaction force characteristic at the coordinates only by the offset amount in the same coding direction as the self-aligning torque; a steering torque inference unit (341) (opposite side steering torque detection means) which detects steering torque at the opposite side of a curve direction of the detected curvature; a limiter processing unit (34e) (offset amount reduction means) which reduces the lateral force offset amount as the steering torque at the opposite side of the curve direction of the detected curvature increases.

Description

操舵制御装置Steering control device
 本発明は、操舵制御装置に関する。 The present invention relates to a steering control device.
 特許文献1には、カーブでのスムーズな通過を目的とし、セルフアライニングトルクに応じてステアリングホイールに付与する操舵反力を旋回中は曲率が大きいほど小さくする技術が開示されている。 Patent Document 1 discloses a technique for reducing the steering reaction force applied to the steering wheel according to the self-aligning torque as the curvature increases with the aim of smooth passage on a curve.
特開平11-78938号公報Japanese Patent Laid-Open No. 11-78938
 しかしながら、上記従来技術にあっては、セルフアライニングトルクに対する操舵反力特性が変化するため、ドライバに違和感を与えるという問題が有った。
  本発明の目的は、ドライバに与える違和感を軽減可能な操舵制御装置を提供することにある。
However, the conventional technology has a problem in that the steering reaction force characteristic with respect to the self-aligning torque changes, which causes the driver to feel uncomfortable.
The objective of this invention is providing the steering control apparatus which can reduce the discomfort given to a driver.
 本発明では、曲率が大きいほど大きなオフセット量を算出し、セルフアライニングトルクと操舵反力を座標軸とする座標上に、セルフアライニングトルクが大きいほど大きな操舵反力となる操舵反力特性を設定し、座標上で当該操舵反力特性をセルフアライニングトルクと同一符号方向へオフセット量だけオフセットする。 In the present invention, a larger offset amount is calculated as the curvature is larger, and a steering reaction force characteristic is set on a coordinate having the self-aligning torque and the steering reaction force as coordinate axes, and a larger steering reaction force as the self-aligning torque is larger. Then, on the coordinates, the steering reaction force characteristic is offset by an offset amount in the same sign direction as the self-aligning torque.
 よって、操舵反力特性を維持した状態で操舵反力を変更することができ、ドライバに与える違和感を軽減できる。 Therefore, the steering reaction force can be changed while maintaining the steering reaction force characteristic, and the uncomfortable feeling given to the driver can be reduced.
実施例1の車両の操舵系を示すシステム図である。1 is a system diagram illustrating a vehicle steering system according to a first embodiment. 転舵制御部19の制御ブロック図である。3 is a control block diagram of a turning control unit 19. FIG. 操舵反力制御部20の制御ブロック図である。3 is a control block diagram of a steering reaction force control unit 20. FIG. 外乱抑制指令転舵角演算部32の制御ブロック図である。4 is a control block diagram of a disturbance suppression command turning angle calculation unit 32. FIG. ヨー角に応じた反発力演算部37の制御ブロック図である。FIG. 6 is a control block diagram of a repulsive force calculation unit 37 according to a yaw angle. 横位置に応じた反発力演算部38の制御ブロック図である。It is a control block diagram of the repulsive force calculation unit 38 according to the lateral position. ヨー角F/B制御および横位置F/B制御の制御領域を示す図である。It is a figure which shows the control area | region of yaw angle F / B control and lateral position F / B control. 高速道路の直線路を走行中の車両が単発的な横風を受けた場合のヨー角変化を示すタイムチャートである。It is a time chart which shows a yaw angle change when the vehicle which is driving | running | working the straight road of a highway receives a single crosswind. 高速道路の直線路を走行中の車両が連続的な横風を受けた場合に横位置F/B制御を実施しないときのヨー角変化および横位置変化を示すタイムチャートである。6 is a time chart showing yaw angle change and lateral position change when lateral position F / B control is not performed when a vehicle traveling on a straight road on a highway receives continuous lateral wind. 高速道路の直線路を走行中の車両が連続的な横風を受けた場合に横位置F/B制御を実施したときのヨー角変化および横位置変化を示すタイムチャートである。6 is a time chart showing a yaw angle change and a lateral position change when lateral position F / B control is performed when a vehicle traveling on a straight road on a highway receives continuous lateral wind. 横力オフセット部34の制御ブロック図である。4 is a control block diagram of a lateral force offset unit 34. FIG. セルフアライニングトルクに応じた操舵反力トルクを表す操舵反力特性がセルフアライニングトルクと同一方向へオフセットした状態を示す図である。It is a figure which shows the state which the steering reaction force characteristic showing the steering reaction force torque according to the self aligning torque offset in the same direction as the self aligning torque. ステアリングホイールの操舵角とドライバの操舵トルクとの関係を示す特性図である。FIG. 6 is a characteristic diagram showing a relationship between a steering angle of a steering wheel and a steering torque of a driver. セルフアライニングトルクに応じた操舵反力トルクを表す操舵反力特性をセルフアライニングトルクと同一方向へオフセットすることにより、ステアリングホイールの操舵角とドライバの操舵トルクとの関係を示す特性が変化した状態を示す図である。By offsetting the steering reaction force characteristic representing the steering reaction torque according to the self-aligning torque in the same direction as the self-aligning torque, the characteristic indicating the relationship between the steering angle of the steering wheel and the steering torque of the driver has changed. It is a figure which shows a state. 操舵反力トルクオフセット部36の制御ブロック図である。4 is a control block diagram of a steering reaction force torque offset unit 36. FIG. 逸脱余裕時間に応じた反力演算部39の制御ブロック図である。FIG. 5 is a control block diagram of a reaction force calculation unit 39 corresponding to a departure allowance time. 横位置に応じた反力演算部40の制御ブロック図である。It is a control block diagram of the reaction force calculation unit 40 according to the lateral position. セルフアライニングトルクに応じた操舵反力トルクを表す操舵反力特性が操舵反力トルクの絶対値が大きくなる方向へオフセットした状態を示す図である。It is a figure which shows the state which the steering reaction force characteristic showing the steering reaction force torque according to a self-aligning torque offset in the direction where the absolute value of a steering reaction force torque becomes large. ステアリングホイールの操舵角とドライバの操舵トルクとの関係を示す特性図である。FIG. 6 is a characteristic diagram showing a relationship between a steering angle of a steering wheel and a steering torque of a driver. セルフアライニングトルクに応じた操舵反力トルクを表す操舵反力特性を操舵反力トルクの絶対値が大きくなる方向へオフセットすることにより、ステアリングホイールの操舵角とドライバの操舵トルクとの関係を示す特性が変化した状態を示す図である。The relationship between the steering angle of the steering wheel and the steering torque of the driver is shown by offsetting the steering reaction force characteristic representing the steering reaction force torque according to the self-aligning torque in the direction in which the absolute value of the steering reaction force torque increases. It is a figure which shows the state from which the characteristic changed. 実施例1の横力オフセット部におけるリミッタ処理部内の制御構成を表すブロック図である。FIG. 3 is a block diagram illustrating a control configuration in a limiter processing unit in a lateral force offset unit according to the first embodiment. 実施例1の反対側に操舵トルクが生じた場合における横力オフセット量の前回値と今回値との関係を表す概略図である。It is the schematic showing the relationship between the last value and lateral value of lateral force offset amount in case steering torque arises on the opposite side of Example 1. 実施例1のB値設定マップである。3 is a B value setting map according to the first embodiment. 実施例1の操舵制御装置において、比較的大きな曲率を有するカーブが連続する際の状態を表す概略図である。In the steering control apparatus of Example 1, it is the schematic showing the state at the time of the curve which has a comparatively big curvature continuing. 実施例1の操舵制御装置において図24に示す状態を経過した場合におけるタイムチャートである。FIG. 25 is a time chart when the state shown in FIG. 24 has elapsed in the steering control device of the first embodiment. FIG.
1 操舵部
2 転舵部
3 バックアップクラッチ
4 SBWコントローラ
5FL,5FR 左右前輪
6 ステアリングホイール
7 コラムシャフト
8 反力モータ
9 操舵角センサ
11 ピニオンシャフト
12 ステアリングギア
13 転舵モータ
14 転舵角センサ
15 ラックギア
16 ラック
17 カメラ
18 車速センサ
19 転舵制御部
19a 加算器
20 操舵反力制御部
20a 減算器
20b 加算器
20c 加算器
21 映像処理部
22 電流ドライバ
23 電流ドライバ
24 ナビゲーションシステム
31 指令転舵角演算部
32 外乱抑制指令転舵角演算部
32a ヨー角演算部
32b 曲率演算部
32c 横位置演算部
32d 加算器
32e 目標ヨーモーメント演算部
32f 目標ヨー加速度演算部
32g 目標ヨーレイト演算部
32h 指令転舵角演算部
32i リミッタ処理部
33 横力演算部
34 横力オフセット部
34a 曲率演算部
34b 上下限リミッタ
34c SATゲイン演算部
34d 乗算器
34e リミッタ処理部
35 SAT演算部
36 操舵反力トルクオフセット部
36a ヨー角演算部
36b 横位置演算部
36c 反力選択部
36d リミッタ処理部
37 ヨー角に応じた反発力演算部
37a 上下限リミッタ
37b ヨー角F/Bゲイン乗算部
37c 車速補正ゲイン乗算部
37d 曲率補正ゲイン乗算部
37e 乗算器
38 横位置に応じた反発力演算部
38a 減算器
38b 上下限リミッタ
38c 距離補正ゲイン乗算部
38d 横位置F/Bゲイン乗算部
38e 車速補正ゲイン乗算部
38f 曲率補正ゲイン乗算部
38g 乗算器
39 逸脱余裕時間に応じ反力演算部
39a 乗算器
39b 除算器
39c 除算器
39d 逸脱余裕時間選択部
39e 逸脱余裕時間に応じた反力演算部
40 横位置に応じた反力演算部
40a 減算器
40b 減算器
40c 横位置偏差選択部
40d 横位置偏差に応じた反力演算部
1 Steering part
2 Steering part
3 Backup clutch
4 SBW controller
5FL, 5FR Front left and right wheels
6 Steering wheel
7 Column shaft
8 Reaction force motor
9 Steering angle sensor
11 Pinion shaft
12 Steering gear
13 Steering motor
14 Steering angle sensor
15 Rack gear
16 racks
17 Camera
18 Vehicle speed sensor
19 Steering control unit
19a Adder
20 Steering reaction force controller
20a subtractor
20b adder
20c adder
21 Video processor
22 Current driver
23 Current driver
24 Navigation system
31 Command turning angle calculator
32 Disturbance suppression command turning angle calculator
32a Yaw angle calculator
32b Curvature calculator
32c Horizontal position calculator
32d adder
32e Target yaw moment calculator
32f Target yaw acceleration calculator
32g target yaw rate calculator
32h Command turning angle calculator
32i limiter processor
33 Lateral force calculator
34 Lateral force offset
34a Curvature calculator
34b Upper / lower limiter
34c SAT gain calculator
34d multiplier
34e Limiter processing section
35 SAT calculator
36 Steering reaction torque offset part
36a Yaw angle calculator
36b Horizontal position calculator
36c Reaction force selector
36d limiter processing section
37 Repulsive force calculation unit according to yaw angle
37a Upper / Lower Limiter
37b Yaw angle F / B gain multiplier
37c Vehicle speed correction gain multiplier
37d Curvature correction gain multiplier
37e multiplier
38 Repulsive force calculation unit according to lateral position
38a subtractor
38b Upper / Lower Limiter
38c Distance correction gain multiplier
38d Horizontal position F / B gain multiplier
38e Vehicle speed correction gain multiplier
38f Curvature correction gain multiplier
38g multiplier
39 Reaction force calculation section according to deviation margin time
39a multiplier
39b Divider
39c divider
39d Deviation margin time selector
39e Reaction force calculation unit according to deviation margin time
40 Reaction force calculation unit according to lateral position
40a subtractor
40b subtractor
40c Horizontal position deviation selector
40d Reaction force calculation unit according to lateral position deviation
 〔実施例1〕
  [システム構成]
  図1は、実施例1の車両の操舵系を示すシステム図である。
  実施例1の操舵装置は、操舵部1、転舵部2、バックアップクラッチ3、SBWコントローラ4を主要な構成とし、ドライバの操舵入力を受ける操舵部1と、左右前輪(転舵輪)5FL,5FRを転舵する転舵部2とが機械的に切り離されたステアバイワイヤ(SBW)システムを採用している。
[Example 1]
[System configuration]
FIG. 1 is a system diagram illustrating a vehicle steering system according to the first embodiment.
The steering device according to the first embodiment mainly includes a steering unit 1, a steering unit 2, a backup clutch 3, and an SBW controller 4, a steering unit 1 that receives a steering input from a driver, and left and right front wheels (steered wheels) 5FL, 5FR. A steer-by-wire (SBW) system in which the steering unit 2 that steers the vehicle is mechanically separated is employed.
 操舵部1は、ステアリングホイール6、コラムシャフト7、反力モータ8および操舵角センサ9を備える。
  コラムシャフト7は、ステアリングホイール6と一体に回転する。
  反力モータ8は、例えば、ブラシレスモータであり、出力軸がコラムシャフト7と同軸の同軸モータであり、SBWコントローラ4からの指令に応じて、コラムシャフト7に操舵反力トルクを出力する。
  操舵角センサ9は、コラムシャフト7の絶対回転角、すなわち、ステアリングホイール6の操舵角を検出する。
The steering unit 1 includes a steering wheel 6, a column shaft 7, a reaction force motor 8, and a steering angle sensor 9.
The column shaft 7 rotates integrally with the steering wheel 6.
The reaction force motor 8 is, for example, a brushless motor, the output shaft of which is a coaxial motor coaxial with the column shaft 7, and outputs a steering reaction force torque to the column shaft 7 in response to a command from the SBW controller 4.
The steering angle sensor 9 detects the absolute rotation angle of the column shaft 7, that is, the steering angle of the steering wheel 6.
 転舵部2は、ピニオンシャフト11、ステアリングギア12、転舵モータ13、および転舵角センサ14を備える。
  ステアリングギア12は、ラック&ピニオン式のステアリングギアであり、ピニオンシャフト11の回転に応じて前輪5L,5Rを転舵する。
  転舵モータ13は、例えば、ブラシレスモータであり、出力軸が図外の減速機を介してラックギア15と接続され、SBWコントローラ4からの指令に応じて、ラック16に前輪5を転舵するための転舵トルクを出力する。
  転舵角センサ14は、転舵モータ13の絶対回転角を検出する。ここで、転舵モータ13の回転角と前輪5の転舵角とは常に一意に定まる相関関係があるため、転舵モータ13の回転角から前輪5の転舵角を検出できる。以下では特に記載しない限り、前輪5の転舵角は転舵モータ13の回転角から算出されたものとする。
  バックアップクラッチ3は、操舵部1のコラムシャフト7と転舵部2のピニオンシャフト11との間に設けられ、解放により操舵部1と転舵部2とを機械的に切り離し、締結により操舵部1と転舵部2とを機械的に接続する。
The steered portion 2 includes a pinion shaft 11, a steering gear 12, a steered motor 13, and a steered angle sensor 14.
The steering gear 12 is a rack and pinion type steering gear, and steers the front wheels 5L and 5R according to the rotation of the pinion shaft 11.
The steered motor 13 is, for example, a brushless motor, whose output shaft is connected to the rack gear 15 via a reduction gear (not shown), and steers the front wheels 5 to the rack 16 in response to a command from the SBW controller 4. The steering torque is output.
The turning angle sensor 14 detects the absolute rotation angle of the turning motor 13. Here, since the rotation angle of the steered motor 13 and the steered angle of the front wheels 5 always have a unique correlation, the steered angle of the front wheels 5 can be detected from the rotational angle of the steered motor 13. In the following description, it is assumed that the turning angle of the front wheels 5 is calculated from the rotation angle of the turning motor 13 unless otherwise specified.
The backup clutch 3 is provided between the column shaft 7 of the steering unit 1 and the pinion shaft 11 of the steering unit 2, and mechanically separates the steering unit 1 and the steering unit 2 by release, and the steering unit 1 by fastening. And the steering unit 2 are mechanically connected.
 SBWコントローラ4には、上記操舵角センサ9および転舵角センサ14に加え、カメラ17により撮影された自車前方の走行路の映像および車速センサ18により検出された車速(車体速)が入力される。
  SBWコントローラ4は、前輪5FL,5FRの転舵角を制御する転舵制御部19と、コラムシャフト7に付与する操舵反力トルクを制御する操舵反力制御部(操舵反力制御手段,コントローラ)20と、映像処理部21とを有する。
  転舵制御部19は、各入力情報に基づいて指令転舵角を生成し、生成した指令転舵角を電流ドライバ22へ出力する。
  電流ドライバ22は、転舵角センサ14により検出される実転舵角を指令転舵角と一致させる角度フィードバックにより転舵モータ13への指令電流を制御する。
  操舵反力制御部20は、各入力情報に基づいて指令操舵反力トルクを生成し、生成した指令操舵反力トルクを電流ドライバ23へ出力する。
  電流ドライバ23は、反力モータ8の電流値から推定される実操舵反力トルクを指令操舵反力トルクと一致させるトルクフィードバックにより反力モータ8への指令電流を制御する。
  映像処理部21は、カメラ17により撮影された自車前方の走行路の映像からエッジ抽出等の画像処理によって走行車線左右の白線(走行路区分線)を認識する。
  加えて、SBWコントローラ4は、SBWシステムのフェール時、バックアップクラッチ3を締結して操舵部1と転舵部2とを機械的に連結し、ステアリングホイール6の操舵によるラック16の軸方向移動を可能とする。このとき、転舵モータ13のアシストトルクによりドライバの操舵力を補助する電動パワーステアリングシステム相当の制御を行ってもよい。
  上記SBWシステムにおいて、各センサ、各コントローラ、各モータを複数設けた冗長系としてもよい。また、転舵制御部19と操舵反力制御部20を別体としてもよい。
In addition to the steering angle sensor 9 and the turning angle sensor 14, the SBW controller 4 is input with the image of the traveling road ahead of the vehicle photographed by the camera 17 and the vehicle speed (vehicle speed) detected by the vehicle speed sensor 18. The
The SBW controller 4 includes a steering control unit 19 that controls the steering angle of the front wheels 5FL and 5FR, and a steering reaction force control unit that controls the steering reaction force torque applied to the column shaft 7 (steering reaction force control means, controller). 20 and a video processing unit 21.
The turning control unit 19 generates a command turning angle based on each input information, and outputs the generated command turning angle to the current driver 22.
The current driver 22 controls the command current to the steered motor 13 by angle feedback that matches the actual steered angle detected by the steered angle sensor 14 with the commanded steered angle.
The steering reaction force control unit 20 generates a command steering reaction force torque based on each input information, and outputs the generated command steering reaction force torque to the current driver 23.
The current driver 23 controls the command current to the reaction force motor 8 by torque feedback that matches the actual steering reaction force torque estimated from the current value of the reaction force motor 8 with the command steering reaction force torque.
The video processing unit 21 recognizes the white lines (traveling line dividing lines) on the left and right of the traveling lane by image processing such as edge extraction from the image of the traveling path ahead of the host vehicle taken by the camera 17.
In addition, when the SBW system fails, the SBW controller 4 engages the backup clutch 3 to mechanically connect the steering unit 1 and the steered unit 2 to move the rack 16 in the axial direction by steering the steering wheel 6. Make it possible. At this time, control equivalent to an electric power steering system that assists the steering force of the driver by the assist torque of the steering motor 13 may be performed.
In the SBW system, a redundant system including a plurality of sensors, controllers, and motors may be used. Further, the steering control unit 19 and the steering reaction force control unit 20 may be separated.
 実施例1では、ドライバの修正操舵量の低減および操舵負担の軽減を狙いとし、スタビリティ制御および修正操舵低減制御を実施する。
  スタビリティ制御は、外乱(横風、路面凹凸、轍、路面カント等)に対する車両の安定性向上を目的とし、2つのフィードバック(F/B)制御を行う。
  1.ヨー角F/B制御
  白線と自車進行方向とのなす角度であるヨー角に応じて転舵角を補正し、外乱により発生したヨー角を減少させる。
  2.横位置F/B制御
  白線までの距離(横位置)に応じて転舵角を補正し、外乱により発生したヨー角の積分値である横位置変化を減少させる。
In the first embodiment, stability control and corrected steering reduction control are performed with the aim of reducing the driver's corrected steering amount and reducing the steering burden.
Stability control performs two feedback (F / B) controls for the purpose of improving vehicle stability against disturbances (crosswind, road surface unevenness, dredging, road surface cant, etc.).
1. Yaw angle F / B control The steering angle is corrected according to the yaw angle, which is the angle between the white line and the direction of travel of the vehicle, and the yaw angle generated by the disturbance is reduced.
2. Lateral position F / B control The steering angle is corrected according to the distance to the white line (lateral position), and the lateral position change, which is the integrated value of the yaw angle caused by the disturbance, is reduced.
 修正操舵低減制御は、ドライバの操舵入力に対する車両の安定性向上を目的とし、3つの反力オフセット制御を行う。
  1.横位置に応じた反力オフセット制御
  横位置に応じてセルフアライニングトルクに応じた操舵反力特性を操舵反力の絶対値が大きくなる方向へオフセットし、ドライバが操舵角中立位置をまたぐ修正操舵を行ったときに操舵トルクの符号が反転するのを抑制する。
  2.逸脱余裕時間に応じた反力オフセット制御
  逸脱余裕時間(白線への到達時間)に応じてセルフアライニングトルクに応じた操舵反力特性を操舵反力の絶対値が大きくなる方向へオフセットし、ドライバが操舵角中立位置をまたぐ修正操舵を行ったときに操舵トルクの符号が反転するのを抑制する。
  3.曲率に応じた反力オフセット制御
  白線の曲率に応じてセルフアライニングトルクに応じた操舵反力特性をセルフアライニングトルクと同一符号方向へオフセットし、旋回時におけるドライバの保舵力を低減すると共に保舵力変化に対する保舵角変化を抑制する。
The corrected steering reduction control performs three reaction force offset controls for the purpose of improving the stability of the vehicle with respect to the driver's steering input.
1. Reaction force offset control according to the lateral position The steering reaction force characteristic according to the self-aligning torque is offset according to the lateral position in the direction in which the absolute value of the steering reaction force increases, and the driver crosses the steering angle neutral position. It is possible to prevent the sign of the steering torque from being reversed when corrective steering is performed.
2. Reaction force offset control according to the deviation margin time Offset the steering reaction force characteristic according to the self-aligning torque in the direction in which the absolute value of the steering reaction force increases according to the deviation margin time (time to reach the white line). When the driver performs corrective steering across the steering angle neutral position, the sign of the steering torque is prevented from being reversed.
3. Reaction force offset control according to the curvature The steering reaction force characteristic according to the self-aligning torque is offset in the same sign direction as the self-aligning torque according to the curvature of the white line to reduce the driver's steering force during turning. In addition, the steering angle change with respect to the steering force change is suppressed.
 [転舵制御部]
  図2は、転舵制御部19の制御ブロック図である。
  SBW指令転舵角演算部31は、操舵角と車速とに基づいてSBW指令転舵角を演算する。
  外乱抑制指令転舵角演算部32は、車速と白線情報とに基づき、スタビリティ制御においてSBW指令転舵角を補正するための外乱抑制指令転舵角を演算する。外乱抑制指令転舵角演算部32の詳細については後述する。
  加算器19aは、SBW指令転舵角と外乱抑制指令転舵角とを加算した値を最終的な指令転舵角として電流ドライバ22へ出力する。
[Steering control unit]
FIG. 2 is a control block diagram of the steering control unit 19.
The SBW command turning angle calculation unit 31 calculates the SBW command turning angle based on the steering angle and the vehicle speed.
The disturbance suppression command turning angle calculation unit 32 calculates a disturbance suppression command turning angle for correcting the SBW command turning angle in the stability control based on the vehicle speed and the white line information. Details of the disturbance suppression command turning angle calculation unit 32 will be described later.
The adder 19a outputs a value obtained by adding the SBW command turning angle and the disturbance suppression command turning angle to the current driver 22 as a final command turning angle.
 [操舵反力制御部]
  図3は、操舵反力制御部20の制御ブロック図である。
  横力演算部33は、操舵角と車速とに基づき、あらかじめ実験等により求めたコンベンショナルな操舵装置における車速毎の操舵角とタイヤ横力との関係を表す操舵角-横力変換マップを参照してタイヤ横力を演算する。操舵角-横力変換マップは、操舵角が大きいほどタイヤ横力が大きく、かつ、操舵角が小さいときは大きいときよりも操舵角の変化量に対するタイヤ横力の変化量が大きく、かつ、車速が高いほどタイヤ横力が小さくなる特性を有する。
  横力オフセット部(オフセット手段)34は、車速と白線情報とに基づき、曲率に応じた反力オフセット制御において操舵反力特性をオフセットするための横力オフセット量を演算する。横力オフセット部34の詳細については後述する。
  減算器20aは、タイヤ横力から横力オフセット量を減算する。
  SAT演算部35は、車速と横力オフセット量によるオフセット後のタイヤ横力とに基づき、あらかじめ実験等により求めたコンベンショナルな操舵装置におけるタイヤ横力と操舵反力トルクとの関係を表す横力-操舵反力トルク変換マップを参照してタイヤ横力によって発生する操舵反力トルクを演算する。タイヤ横力-操舵反力トルク変換マップは、タイヤ横力が大きいほど操舵反力トルクが大きく、タイヤ横力が小さいときは大きいときよりもタイヤ横力の変化量に対する操舵反力トルクの変化量が大きく、かつ、車速が高いほど操舵反力トルクが小さくなる特性を有する。この特性は、コンベンショナルな操舵装置において、路面反力によって発生する車輪が直進状態に戻ろうとするセルフアライニングトルクによってステアリングホイールに発生する反力を模擬したものである。
[Steering reaction force control unit]
FIG. 3 is a control block diagram of the steering reaction force control unit 20.
The lateral force calculation unit 33 refers to a steering angle-lateral force conversion map that represents the relationship between the steering angle for each vehicle speed and the tire lateral force in a conventional steering device that has been obtained in advance through experiments or the like based on the steering angle and the vehicle speed. To calculate the tire lateral force. In the steering angle-lateral force conversion map, the larger the steering angle, the greater the tire lateral force, and when the steering angle is small, the amount of change in the tire lateral force relative to the amount of change in the steering angle is greater than when the steering angle is large. The tire has a characteristic that the tire lateral force decreases as the value increases.
The lateral force offset unit (offset means) 34 calculates a lateral force offset amount for offsetting the steering reaction force characteristic in the reaction force offset control according to the curvature based on the vehicle speed and the white line information. Details of the lateral force offset unit 34 will be described later.
The subtractor 20a subtracts the lateral force offset amount from the tire lateral force.
The SAT calculation unit 35 is a lateral force that represents the relationship between the tire lateral force and the steering reaction force torque in the conventional steering system, which is obtained in advance through experiments or the like based on the vehicle speed and the tire lateral force after offset based on the lateral force offset amount. The steering reaction force torque generated by the tire lateral force is calculated with reference to the steering reaction force torque conversion map. The tire lateral force-steering reaction torque conversion map shows that the larger the tire lateral force is, the larger the steering reaction torque becomes. When the tire lateral force is small, the amount of change in the steering reaction torque with respect to the amount of change in the tire lateral force is larger than when the tire lateral force is large. And the steering reaction torque decreases as the vehicle speed increases. This characteristic simulates the reaction force generated in the steering wheel by the self-aligning torque in which the wheel generated by the road surface reaction force returns to the straight traveling state in the conventional steering device.
 加算器20bは、操舵反力トルクとステアリング特性に応じた操舵反力トルク成分(ばね項、粘性項、慣性項)を加算する。ばね項は操舵角に比例する成分であり、操舵角に所定のゲインを乗じて算出する。粘性項は操舵角速度に比例する成分であり操舵角速度に所定のゲインを乗じて算出する。慣性項は操舵角加速度に比例する成分であり、操舵角加速度に所定のゲインを乗じて算出する。
  操舵反力トルクオフセット部36は、車速と自車前方の走行路の映像とに基づき、横位置または逸脱余裕時間に応じた反力オフセット制御において操舵反力特性をオフセットするための操舵反力トルクオフセット量を演算する。操舵反力トルクオフセット部36の詳細については後述する。
  加算器20cは、ステアリング特性に応じた操舵反力トルク成分を加算した後の操舵反力トルクと操舵トルクオフセット量とを加算した値を最終的な指令操舵反力トルクとして電流ドライバ23へ出力する。
The adder 20b adds the steering reaction force torque and the steering reaction force torque component (spring term, viscosity term, inertia term) corresponding to the steering characteristics. The spring term is a component proportional to the steering angle, and is calculated by multiplying the steering angle by a predetermined gain. The viscosity term is a component proportional to the steering angular velocity, and is calculated by multiplying the steering angular velocity by a predetermined gain. The inertia term is a component proportional to the steering angular acceleration, and is calculated by multiplying the steering angular acceleration by a predetermined gain.
The steering reaction force torque offset unit 36 is a steering reaction force torque for offsetting the steering reaction force characteristic in the reaction force offset control according to the lateral position or the deviation margin time based on the vehicle speed and the image of the traveling road ahead of the host vehicle. Calculate the offset amount. Details of the steering reaction torque offset unit 36 will be described later.
The adder 20c outputs a value obtained by adding the steering reaction force torque after adding the steering reaction force torque component corresponding to the steering characteristics and the steering torque offset amount to the current driver 23 as a final command steering reaction force torque. .
 [外乱抑制指令転舵角演算部]
  図4は、外乱抑制指令転舵角演算部32の制御ブロック図である。
  ヨー角演算部32aは、前方注視点での白線と自車進行方向とのなす角度であるヨー角を演算する。前方注視点でのヨー角は、所定時間(例えば、0.5秒)後の白線と自車進行方向とのなす角度とする。カメラ17により撮影された走行路の映像に基づいてヨー角を演算することで、簡単かつ高精度にヨー角を検出できる。
  曲率演算部32bは、前方注視点での白線の曲率を演算する。
  横位置演算部32cは、前方注視点先での白線までの距離を演算する。
  ヨー角に応じた反発力演算部37は、ヨー角と曲率と車速とに基づき、ヨー角F/B制御において外乱により発生したヨー角を減らすための車両の反発力を演算する。ヨー角に応じた反発力演算部37の詳細については後述する。
[Disturbance suppression command turning angle calculator]
FIG. 4 is a control block diagram of the disturbance suppression command turning angle calculation unit 32.
The yaw angle calculator 32a calculates a yaw angle that is an angle formed by the white line at the forward gazing point and the traveling direction of the host vehicle. The yaw angle at the forward gazing point is an angle formed by the white line after a predetermined time (for example, 0.5 seconds) and the traveling direction of the vehicle. By calculating the yaw angle based on the image of the travel path taken by the camera 17, the yaw angle can be detected easily and with high accuracy.
The curvature calculation unit 32b calculates the curvature of the white line at the forward gazing point.
The lateral position calculation unit 32c calculates the distance to the white line at the front gazing point.
Based on the yaw angle, the curvature, and the vehicle speed, the repulsive force calculation unit 37 corresponding to the yaw angle calculates the vehicle repulsive force for reducing the yaw angle generated by the disturbance in the yaw angle F / B control. Details of the repulsive force calculation unit 37 according to the yaw angle will be described later.
 横位置に応じた反発力演算部38は、ヨー角と曲率と車速と前方注視点での白線までの距離とに基づき、横位置F/B制御において外乱により発生した横位置変化を減らすための車両の反発力を演算する。横位置に応じた反発力演算部38の詳細については後述する。
  加算器32dは、ヨー角に応じた反発力と横位置に応じた反発力とを加算し、横方向反発力を演算する。
  目標ヨーモーメント演算部32eは、横方向反発力、ホイールベース(車軸間距離)、後輪軸重および前輪軸重に基づいて目標ヨーモーメントを演算する。具体的には、横方向反発力に対し、車両重量(前輪軸重+後輪軸重)に対する後輪軸重の割合と、ホイールベースとを乗じた値を目標ヨーモーメントとする。
  目標ヨー加速度演算部32fは、目標ヨーモーメントにヨー慣性モーメント係数を乗じて目標ヨー加速度を演算する。
  目標ヨーレイト演算部32gは、目標ヨー加速度に車頭時間を乗じて目標ヨーレイトを演算する。
Based on the yaw angle, curvature, vehicle speed, and distance to the white line at the front gazing point, the repulsive force calculation unit 38 according to the lateral position is used to reduce lateral position changes caused by disturbances in lateral position F / B control. Calculate the repulsive force of the vehicle. Details of the repulsive force calculation unit 38 according to the lateral position will be described later.
The adder 32d adds the repulsive force according to the yaw angle and the repulsive force according to the lateral position, and calculates the lateral repulsive force.
The target yaw moment calculator 32e calculates a target yaw moment based on the lateral repulsive force, the wheel base (distance between the axles), the rear wheel axle weight, and the front wheel axle weight. Specifically, a value obtained by multiplying the lateral repulsive force by the ratio of the rear wheel axle weight to the vehicle weight (front wheel axle weight + rear wheel axle weight) and the wheel base is set as the target yaw moment.
The target yaw acceleration calculation unit 32f multiplies the target yaw moment by the yaw inertia moment coefficient to calculate the target yaw acceleration.
The target yaw rate calculation unit 32g calculates the target yaw rate by multiplying the target yaw acceleration by the vehicle head time.
 指令転舵角演算部32hは、目標ヨーレイトφ*、ホイールベースWHEEL_BASE、車速Vおよび車両の特性速度vChに基づき、下記の式を参照して外乱抑制指令転舵角δst *を演算する。ここで、車両の特性速度Vchとは、既知の"アッカーマン方程式"の中のパラメータであり、車両のセルフステアリング特性を表すものである。
  δst * = (φ*×WHEEL_BASE×(1+(V/vCh)2)×180)/(V×M_PI)
  なお、M_PIは所定の係数である。
  リミッタ処理部32iは、外乱抑制指令転舵角δst *の最大値および変化率の上限を制限する。最大値は、コンベンショナルな操舵装置(操舵部と転舵部とが機械的に接続された)において、ステアリングホイール6の操舵角が中立位置付近の遊びの角度範囲(例えば、左右3°)にあるときの当該遊びの範囲に対応する前輪5FL,5FRの転舵角範囲(例えば、左右0.2°)とする。
The command turning angle calculation unit 32h calculates a disturbance suppression command turning angle δ st * with reference to the following formula based on the target yaw rate φ * , the wheel base WHEEL_BASE, the vehicle speed V, and the vehicle characteristic speed vCh. Here, the vehicle characteristic speed V ch is a parameter in the known “Ackermann equation” and represents the self-steering characteristic of the vehicle.
δ st * = (φ * × WHEEL_BASE × (1+ (V / vCh) 2 ) × 180) / (V × M_PI)
M_PI is a predetermined coefficient.
The limiter processing unit 32i limits the maximum value of the disturbance suppression command turning angle δ st * and the upper limit of the change rate. The maximum value is in a play angle range (for example, 3 ° to the left and right) of the steering wheel 6 near the neutral position in a conventional steering device (the steering unit and the steering unit are mechanically connected). The turning angle range of the front wheels 5FL and 5FR corresponding to the range of play at that time (for example, right and left 0.2 °).
 図5は、ヨー角に応じた反発力演算部37の制御ブロック図である。
  上下限リミッタ37aは、ヨー角に上下限リミッタ処理を施す。上下限リミッタは、ヨー角が正の値の場合(白線と自車進行方向の延長線とが交差するときのヨー角を正とする。)には、外乱を抑制可能な所定値以上、かつ、車両が振動的となる値およびドライバの操舵によって発生する値未満の値(例えば、1°)とし、ヨー角が負の場合には0とする。
  ヨー角F/Bゲイン乗算部37bは、リミッタ処理後のヨー角にヨー角F/Bゲインを乗じる。ヨー角F/Bゲインは、制御量不足を回避しつつ応答性を確保できる所定値以上、かつ、車両が振動的になる値およびドライバが操舵角と転舵角との中立ずれを感じる値未満とする。
FIG. 5 is a control block diagram of the repulsive force calculation unit 37 according to the yaw angle.
The upper / lower limiter 37a performs upper / lower limiter processing on the yaw angle. When the yaw angle is a positive value (the yaw angle when the white line and the extension line in the traveling direction of the vehicle intersect is positive), the upper / lower limiter is greater than or equal to a predetermined value capable of suppressing disturbance, and A value that is less than a value that causes the vehicle to vibrate and a value that is generated by the steering of the driver (for example, 1 °), and 0 if the yaw angle is negative.
The yaw angle F / B gain multiplication unit 37b multiplies the yaw angle after the limiter process by the yaw angle F / B gain. The yaw angle F / B gain is equal to or greater than a predetermined value that can ensure responsiveness while avoiding insufficient control amount, and less than the value at which the vehicle vibrates and the driver feels the neutral deviation between the steering angle and the turning angle. And
 車速補正ゲイン乗算部37cは、車速に車速補正ゲインを乗じる。車速補正ゲインは、0~70km/hの範囲で最大値をとり、70~130km/hの範囲で徐々に減少し、130km/h以上の範囲で最小値(0)となる特性とする。
  曲率補正ゲイン乗算部37dは、曲率に曲率補正ゲインを乗じる。曲率補正ゲインは、曲率が大きいほど小さくなる特性とし、上限および下限(0)を設定する。
  乗算器37eは、ヨー角F/Bゲイン乗算部37b、車速補正ゲイン乗算部37cおよび曲率補正ゲイン乗算部37dの各出力を乗じてヨー角に応じた反発力を求める。
The vehicle speed correction gain multiplication unit 37c multiplies the vehicle speed by the vehicle speed correction gain. The vehicle speed correction gain has a maximum value in the range of 0 to 70 km / h, a gradual decrease in the range of 70 to 130 km / h, and a minimum value (0) in the range of 130 km / h or higher.
The curvature correction gain multiplication unit 37d multiplies the curvature by the curvature correction gain. The curvature correction gain has a characteristic that decreases as the curvature increases, and an upper limit and a lower limit (0) are set.
The multiplier 37e multiplies the outputs of the yaw angle F / B gain multiplication unit 37b, the vehicle speed correction gain multiplication unit 37c, and the curvature correction gain multiplication unit 37d to obtain a repulsive force according to the yaw angle.
 図6は、横位置に応じた反発力演算部38の制御ブロック図である。
  減算器38aは、あらかじめ設定された横位置閾値(例えば、90cm)から前方注視点先での白線までの距離を減じて横位置偏差を求める。
  上下限リミッタ38bは、横位置偏差に上下限リミッタ処理を施す。上下限リミッタは、横位置偏差が正の値の場合には所定の正の値をとり、横位置偏差が負の値の場合には0とする。
  距離補正ゲイン乗算部38cは、前方注視点先での白線までの距離に距離補正ゲインを乗じる。距離補正ゲインは、白線までの距離が所定値以下である場合は最大値をとり、所定値を超える場合は距離が長くなるほど小さくなる特性とし、下限を設定する。
FIG. 6 is a control block diagram of the repulsive force calculation unit 38 according to the lateral position.
The subtractor 38a obtains the lateral position deviation by subtracting the distance from the preset lateral position threshold (for example, 90 cm) to the white line at the front gazing point.
The upper / lower limiter 38b performs upper / lower limiter processing on the lateral position deviation. The upper / lower limiter takes a predetermined positive value when the lateral position deviation is a positive value, and is 0 when the lateral position deviation is a negative value.
The distance correction gain multiplication unit 38c multiplies the distance to the white line at the front gaze point by the distance correction gain. The distance correction gain takes a maximum value when the distance to the white line is equal to or smaller than a predetermined value, and when the distance exceeds the predetermined value, the distance correction gain has a characteristic that becomes smaller as the distance becomes longer, and a lower limit is set.
 横位置F/Bゲイン乗算部38dは、距離補正ゲイン乗算部38cによる補正後の白線までの距離に横位置F/Bゲインを乗じる。横位置F/Bゲインは、制御量不足を回避しつつ応答性を確保できる所定値以上、かつ、車両が振動的になる値およびドライバが中立ずれを感じる値未満とし、さらに、ヨー角F/Bゲイン演算部37bのヨー角F/Bゲインよりも小さな値に設定する。
  車速補正ゲイン乗算部38eは、車速に車速補正ゲインを乗じる。車速補正ゲインは、0~70km/hの範囲で最大値をとり、70~130km/hの範囲で徐々に減少し、130km/h以上の範囲で最小値(0)となる特性とする。
  曲率補正ゲイン乗算部38fは、曲率に曲率補正ゲインを乗じる。曲率補正ゲインは、曲率が大きいほど小さくなる特性とし、上限および下限(0)を設定する。
  乗算器38gは、横位置F/Bゲイン乗算部38d、車速補正ゲイン乗算部38eおよび曲率補正ゲイン乗算部38fの各出力を乗じて横位置に応じた反発力を求める。
The horizontal position F / B gain multiplication unit 38d multiplies the distance to the white line corrected by the distance correction gain multiplication unit 38c by the horizontal position F / B gain. The lateral position F / B gain is set to a value that is equal to or greater than a predetermined value that can ensure responsiveness while avoiding a shortage of control amount, and that is less than a value that makes the vehicle vibrate and a value that the driver feels neutral deviation. A value smaller than the yaw angle F / B gain of the B gain calculation unit 37b is set.
The vehicle speed correction gain multiplication unit 38e multiplies the vehicle speed by the vehicle speed correction gain. The vehicle speed correction gain has a maximum value in the range of 0 to 70 km / h, a gradual decrease in the range of 70 to 130 km / h, and a minimum value (0) in the range of 130 km / h or higher.
The curvature correction gain multiplication unit 38f multiplies the curvature by the curvature correction gain. The curvature correction gain has a characteristic that decreases as the curvature increases, and an upper limit and a lower limit (0) are set.
The multiplier 38g multiplies each output of the lateral position F / B gain multiplication unit 38d, the vehicle speed correction gain multiplication unit 38e, and the curvature correction gain multiplication unit 38f to obtain a repulsive force according to the lateral position.
 [スタビリティ制御作用]
  実施例1では、スタビリティ制御として、外乱により発生したヨー角を減少させるヨー角F/B制御と、外乱により発生したヨー角の積分値である横位置変化を減少させる横位置F/B制御を実施する。ヨー角F/B制御は、ヨー角が発生した場合、横位置にかかわらず実施し、横位置F/B制御は、白線までの距離が所定の横位置閾値(90cm)以下となった場合に実施する。すなわち、走行車線中央付近は横位置F/B制御の不感帯となる。両F/B制御の制御領域を図7に示す。φはヨー角である。
[Stability control action]
In the first embodiment, as the stability control, the yaw angle F / B control for reducing the yaw angle caused by the disturbance and the lateral position F / B control for reducing the lateral position change that is an integral value of the yaw angle caused by the disturbance. To implement. The yaw angle F / B control is performed regardless of the lateral position when the yaw angle occurs.The lateral position F / B control is performed when the distance to the white line is equal to or less than the predetermined lateral position threshold (90 cm). carry out. That is, the vicinity of the center of the traveling lane is a dead zone for lateral position F / B control. The control area of both F / B controls is shown in FIG. φ is the yaw angle.
 図8は、高速道路の直線路を走行中の車両が単発的な横風を受けた場合のヨー角変化を示すタイムチャートであり、車両は走行車線の中央付近を走行しているものとする。車両が単発的な横風を受けてヨー角が発生すると、ヨー角F/B制御では、ヨー角に応じた反発力を演算し、当該反発力を得るための外乱抑制指令転舵角を求め、操舵角と車速とに基づくSBW指令転舵角を補正する。
  車両を走行車線に沿って走行させる場合、特に直線路では、白線の方向と自車進行方向とは一致しているため、ヨー角はゼロとなる。つまり、実施例1のヨー角F/B制御では、発生したヨー角を外乱によるものとみなし、ヨー角を減少させることにより、特に直進時において外乱に対する車両の安定性向上を図ることができ、ドライバの修正操舵量を低減できる。
FIG. 8 is a time chart showing a change in yaw angle when a vehicle traveling on a straight road on a highway receives a single crosswind, and it is assumed that the vehicle is traveling near the center of the traveling lane. When the vehicle receives a single crosswind and a yaw angle occurs, the yaw angle F / B control calculates the repulsive force according to the yaw angle, finds the disturbance suppression command turning angle to obtain the repulsive force, The SBW command turning angle based on the steering angle and the vehicle speed is corrected.
When the vehicle travels along the traveling lane, the yaw angle is zero because the direction of the white line and the traveling direction of the vehicle coincide with each other, particularly on a straight road. In other words, in the yaw angle F / B control of the first embodiment, the generated yaw angle is considered to be due to disturbance, and by reducing the yaw angle, the stability of the vehicle against disturbance can be improved particularly during straight running. The driver's correction steering amount can be reduced.
 従来、横風等の外乱による車両挙動への影響を抑制するものとして、コンベンショナルな操舵装置では、外乱抑制のための転舵トルクを操舵系に付与するものが知られており、SBWシステムでは、外乱抑制のための転舵を促す操舵反力成分をステアリングホイールに付与するものが知られている。ところが、これら従来の操舵装置では、操舵反力の変動が生じるため、ドライバに違和感を与えてしまう。
  これに対し、実施例1のヨー角F/B制御を含むスタビリティ制御では、ステアリングホイール6と前輪5L,5Rとが機械的に切り離されたSBWシステムの特徴である、ステアリングホイール6と前輪5L,5Rとを互いに独立して制御可能な点に着目し、操舵角と車速とに応じたSBW指令転舵角とヨー角に応じた外乱抑制指令転舵角とを加算した指令転舵角に基づいて前輪5L,5Rの転舵角を制御する一方、操舵角と車速とに基づいてタイヤ横力を推定し、推定したタイヤ横力と車速とに応じた指令操舵反力に基づいて操舵反力を制御する。
  すなわち、外乱抑制分の転舵角を直接前輪5L,5Rに与えるため、外乱抑制のための転舵を促す操舵反力成分の付与が不要となる。さらに、操舵角から推定したタイヤ横力に応じた操舵反力を付与することで、外乱抑制のための転舵によって生じるタイヤ横力の変動が操舵反力に反映されないため、ドライバに与える違和感を軽減できる。従来のSBWシステムでは、センサにより検出したラック軸力や転舵角からタイヤ横力を推定し、推定したタイヤ横力に応じた操舵反力を付与している。このため、外乱抑制のための転舵によって生じるタイヤ横力の変動が操舵反力に必ず反映されてしまい、ドライバの違和感となる。実施例1では、ドライバの操舵によって生じたタイヤ横力のみが操舵反力に反映され、外乱抑制のための転舵によって操舵反力が変動しないため、ドライバに与える違和感を軽減できる。
Conventionally, in order to suppress the influence on the vehicle behavior due to disturbances such as crosswinds, it is known that conventional steering devices give steering torque to the steering system to suppress disturbances. There is known one that imparts a steering reaction force component that promotes turning for suppression to a steering wheel. However, in these conventional steering devices, the steering reaction force fluctuates, which makes the driver feel uncomfortable.
On the other hand, in the stability control including the yaw angle F / B control of the first embodiment, the steering wheel 6 and the front wheel 5L, which are the characteristics of the SBW system in which the steering wheel 6 and the front wheels 5L and 5R are mechanically separated, are provided. , 5R can be controlled independently of each other, and the command turning angle is obtained by adding the SBW command turning angle according to the steering angle and the vehicle speed and the disturbance suppression command turning angle according to the yaw angle. Based on this, the steering angle of the front wheels 5L, 5R is controlled, while the tire lateral force is estimated based on the steering angle and the vehicle speed, and the steering reaction force is determined based on the commanded steering reaction force according to the estimated tire lateral force and the vehicle speed. Control power.
That is, since the turning angle corresponding to the disturbance suppression is directly given to the front wheels 5L and 5R, it is not necessary to provide a steering reaction force component that prompts the steering for disturbance suppression. Furthermore, by applying a steering reaction force according to the tire lateral force estimated from the steering angle, the fluctuation of the tire lateral force caused by the steering for suppressing the disturbance is not reflected in the steering reaction force, so the driver feels uncomfortable. Can be reduced. In the conventional SBW system, a tire lateral force is estimated from a rack axial force and a turning angle detected by a sensor, and a steering reaction force corresponding to the estimated tire lateral force is applied. For this reason, the fluctuation of the tire lateral force generated by the steering for suppressing the disturbance is always reflected in the steering reaction force, which makes the driver feel uncomfortable. In the first embodiment, only the tire lateral force generated by the driver's steering is reflected in the steering reaction force, and the steering reaction force does not fluctuate due to the steering for suppressing the disturbance. Therefore, the uncomfortable feeling given to the driver can be reduced.
 ここで、外乱抑制分の転舵角を直接前輪5L,5Rに与える場合、操舵角と転舵角との中立ずれが問題となるが、実施例1では、外乱抑制指令転舵角を、コンベンショナルな操舵装置において、ステアリングホイール6が操舵角中立位置付近の遊びの角度範囲(左右3°)にあるときの当該遊びの範囲に対応する前輪5FL,5FRの転舵角範囲(左右0.2°)に設定している。外乱によるヨー角の発生は、旋回時よりも直進時に顕著であり、直進時、操舵角は操舵角中立位置付近に位置している。つまり、ヨー角F/B制御による転舵角の補正は、操舵角中立位置付近で実施されることはほとんどであるため、外乱抑制指令転舵角の付与に伴う操舵角と転舵角との中立ずれ量をステアリングの遊びの範囲に抑えることで、中立ずれに伴う違和感を抑制できる。
  また、外乱抑制指令転舵角を左右0.2°の範囲に制限しているため、スタビリティ制御中であってもドライバは操舵入力によって車両の進行方向を所望の方向に変化させることができる。つまり、ドライバの操舵入力によって生じる転舵角の変化量に対し、外乱抑制指令転舵角による転舵角の補正量が微小であるため、ドライバの操舵を妨げることなく外乱に対する車両の安定性向上を実現できる。
Here, when the turning angle for disturbance suppression is directly given to the front wheels 5L and 5R, the neutral deviation between the steering angle and the turning angle becomes a problem. However, in the first embodiment, the disturbance suppression command turning angle is changed to conventional. When the steering wheel 6 is in the play angle range near the steering angle neutral position (left and right 3 °), the steering angle range of the front wheels 5FL and 5FR corresponding to the play range (left and right 0.2 °) It is set. The generation of the yaw angle due to disturbance is more conspicuous when traveling straight than when turning, and the steering angle is located near the steering angle neutral position when traveling straight. In other words, the correction of the turning angle by the yaw angle F / B control is almost always performed near the steering angle neutral position, so the steering angle and the turning angle associated with the provision of the disturbance suppression command turning angle By suppressing the amount of neutral deviation within the range of steering play, it is possible to suppress a sense of incongruity associated with neutral deviation.
Further, since the disturbance suppression command turning angle is limited to a range of 0.2 ° to the left and right, the driver can change the traveling direction of the vehicle to a desired direction by the steering input even during the stability control. In other words, the amount of correction of the turning angle based on the disturbance suppression command turning angle is very small with respect to the amount of change in the turning angle caused by the driver's steering input. Can be realized.
 従来、車両の横方向運動を制御するものとして、車両の走行車線逸脱傾向が検出されると車両に逸脱を回避するヨーモーメントを付与する車線逸脱防止制御や、車両が走行車線の中央付近を走行するよう車両にヨーモーメントを付与するレーンキープ制御が公知である。ところが、車線逸脱防止制御では、制御介入の閾値を持った制御であり、走行車線の中央付近では制御が作動しないため、外乱に対する車両の安定性を確保できない。また、ドライバが車両を走行車線の端に寄せたい場合でも閾値によって制御介入がなされるため、ドライバに煩わしさを与えてしまう。一方、レーンキープ制御では、目標位置(目標ライン)を持った制御であり、外乱に対する車両の安定性を確保できるものの、目標ラインから外れたラインを走行させることはできない。加えて、ドライバがステアリングホイールの把持力を小さくすると手放し状態との判定により制御が解除されるため、ドライバは常にステアリングホイールを一定以上の力で把持しておく必要が有り、ドライバの操舵負荷が大きい。
  これに対し、実施例1のヨー角F/B制御は、制御介入の閾値を持たないため、シームレスな制御により常に外乱に対する安定性を確保できる。さらに、目標位置を持たないため、ドライバは車両を好きなラインで走行させることができる。加えて、ステアリングホイール6を軽く持っている場合でも制御が解除されることはないため、ドライバの操舵負荷を小さくできる。
Conventionally, as control of the lateral movement of the vehicle, lane departure prevention control that gives the vehicle a yaw moment that avoids departure when a vehicle traveling lane departure tendency is detected, or the vehicle travels near the center of the traveling lane. Lane keeping control for imparting a yaw moment to a vehicle is known. However, the lane departure prevention control is a control having a threshold for control intervention, and the control does not operate in the vicinity of the center of the traveling lane, so the stability of the vehicle against disturbance cannot be ensured. Further, even when the driver wants to bring the vehicle to the end of the traveling lane, control intervention is performed according to the threshold value, which causes trouble for the driver. On the other hand, in the lane keep control, the control has a target position (target line), and although the stability of the vehicle against disturbance can be ensured, a line deviating from the target line cannot be driven. In addition, if the driver reduces the gripping force of the steering wheel, the control is canceled by determining that the steering wheel is released, so the driver must always grip the steering wheel with a certain force or more, and the driver's steering load is reduced. large.
On the other hand, since the yaw angle F / B control of the first embodiment does not have a threshold value for control intervention, it is possible to always ensure stability against disturbance by seamless control. Furthermore, since it does not have a target position, the driver can drive the vehicle along a favorite line. In addition, even when the steering wheel 6 is held lightly, the control is not released, and the steering load on the driver can be reduced.
 図9は、高速道路の直線路を走行中の車両が連続的な横風を受けた場合に横位置F/B制御を実施しないときのヨー角変化および横位置変化を示すタイムチャートであり、車両は走行車線の中央付近を走行しているものとする。車両が連続的な横風を受けてヨー角が発生すると、ヨー角F/B制御によってヨー角は低減されるものの、車両は連続的な外乱を受けて横流れしている。ヨー角F/B制御は、ヨー角を減少させるものであって、ヨー角ゼロの場合は転舵角の補正を行わないため、外乱により発生したヨー角の積分値である横位置変化を直接的に減少させることはできないからである。なお、ヨー角に応じた反発力を大きな値とすることで、横位置変化を間接的に抑制する(ヨー角の積分値の増加を抑制する)ことは可能であるが、外乱抑制指令転舵角の最大値はドライバに違和感を与えないよう、左右0.2°に制限されていることから、ヨー角F/B制御のみで車両の横流れを効果的に抑制することは難しい。さらに、ヨー角に応じた反発力を求めるためのヨー角F/Bゲインは、ドライバがヨー角変化に気付く前にヨー角を収束させる必要が有るため、出来るだけ大きな値としているのに対し、そのままでは車両が振動的となるため、ヨー角F/Bゲインに乗じるヨー角を上下限リミッタ37aによって上限(1°)以下に制限している。すなわち、ヨー角に応じた反発力は実際のヨー角よりも小さなヨー角に対応した反発力であるため、この点からもヨー角F/B制御のみで車両の横流れを効果的に抑制するのは困難であることがわかる。 FIG. 9 is a time chart showing the yaw angle change and the lateral position change when the lateral position F / B control is not performed when the vehicle traveling on the straight road of the expressway receives continuous lateral wind. Is driving near the center of the driving lane. When the vehicle receives a continuous crosswind and generates a yaw angle, the yaw angle is reduced by the yaw angle F / B control, but the vehicle is subjected to a continuous disturbance and flows laterally. The yaw angle F / B control reduces the yaw angle, and when the yaw angle is zero, the turning angle is not corrected, so the lateral position change, which is the integrated value of the yaw angle caused by the disturbance, is directly detected. This is because it cannot be reduced. In addition, it is possible to indirectly suppress the lateral position change (suppress the increase in the integral value of the yaw angle) by making the repulsive force according to the yaw angle a large value, but disturbance suppression command steering Since the maximum value of the angle is limited to 0.2 ° left and right so as not to give the driver a sense of incongruity, it is difficult to effectively suppress the lateral flow of the vehicle only by the yaw angle F / B control. Furthermore, the yaw angle F / B gain for determining the repulsive force according to the yaw angle needs to converge the yaw angle before the driver notices the yaw angle change. Since the vehicle becomes vibrating as it is, the yaw angle multiplied by the yaw angle F / B gain is limited to the upper limit (1 °) or less by the upper / lower limiter 37a. In other words, the repulsive force according to the yaw angle is a repulsive force corresponding to a yaw angle smaller than the actual yaw angle. From this point, the lateral flow of the vehicle can be effectively suppressed only by the yaw angle F / B control. Proves difficult.
 そこで、実施例1のスタビリティ制御では、横位置F/B制御を導入し、定常的な外乱によって車両が横流れするのを抑制している。図10は、高速道路の直線路を走行中の車両が連続的な横風を受けた場合に横位置F/B制御を実施したときのヨー角変化および横位置変化を示すタイムチャートであり、横位置F/B制御では、走行車線中央付近を走行中の車両が連続的な横風を受けて横流れし、白線までの距離が横位置閾値以下になると、横位置変化(≒ヨー角積分値)に応じた反発力を演算する。外乱抑制指令転舵角演算部32では、横位置に応じた反発力とヨー角に応じた反発力とを加算した横方向反発力に基づく外乱抑制指令転舵角を演算し、SBW指令転舵角を補正する。すなわち、横位置F/B制御では、横位置に応じた外乱抑制指令転舵角によってSBW指令転舵角を補正するため、定常的な外乱による横位置変化を直接的に減少させることが可能であり、車両の横流れを抑制できる。言い換えると、ヨー角F/B制御を行う車両の走行位置を、横位置F/B制御の不感帯である走行車線中央付近に戻すことができる。 Therefore, in the stability control of the first embodiment, the lateral position F / B control is introduced to suppress the lateral flow of the vehicle due to the steady disturbance. FIG. 10 is a time chart showing changes in yaw angle and lateral position when lateral position F / B control is performed when a vehicle traveling on a straight road on a highway receives continuous lateral wind. In position F / B control, when the vehicle running near the center of the lane is subjected to continuous crosswinds and flows laterally, and the distance to the white line is less than the lateral position threshold, the lateral position changes (≈ yaw angle integral value). The corresponding repulsive force is calculated. The disturbance suppression command turning angle calculation unit 32 calculates the disturbance suppression command turning angle based on the lateral repulsive force that is the sum of the repulsive force according to the lateral position and the repulsive force according to the yaw angle. Correct the corners. That is, in the lateral position F / B control, the SBW command turning angle is corrected by the disturbance suppression command turning angle according to the lateral position, so it is possible to directly reduce the lateral position change due to steady disturbance. Yes, the lateral flow of the vehicle can be suppressed. In other words, the travel position of the vehicle that performs the yaw angle F / B control can be returned to the vicinity of the center of the travel lane, which is the dead zone of the lateral position F / B control.
 以上のように、実施例1のスタビリティ制御は、過渡的な外乱によるヨー角変化をヨー角F/B制御により減少させ、定常的な外乱によるヨー角積分値(横位置変化)を横位置F/B制御により減少させることで、過渡的および定常的な外乱に対する車両の安定性を共に向上できる。
  さらに、実施例1のスタビリティ制御は、制御(外乱抑制指令転舵角の付与)によって生じる車両挙動をドライバに気付かれない程度、かつ、ドライバの操舵によって発生する車両挙動変化を妨げない程度に制限し、かつ、制御によって生じるセルフアライニングトルクの変化を操舵反力に反映させないため、ドライバにスタビリティ制御中であることを意識させることなく実施可能である。これにより、あたかも外乱に対する安定性に優れた車体諸元を持つ車両の振る舞いを模擬できる。
  なお、横位置F/B制御において横位置に応じた反発力を求めるための横位置F/Bゲインは、ヨー角F/Bゲインよりも小さな値に設定している。上述したように、ヨー角F/B制御は、過渡的な外乱によるヨー角の変化をドライバが感じる前にヨー角を収束させる必要上、高応答性が求められるのに対し、横位置F/B制御は、横位置変化が増加するのを止めることが求められること、およびヨー角積分値の蓄積によって横位置が変化するのに時間が掛かることから、ヨー角F/B制御ほどの応答性は必要としていないからである。加えて、仮に横位置F/Bゲインを大きくすると、外乱の大小によって制御量が大きく変動し、ドライバに違和感を与えるからである。
As described above, the stability control of the first embodiment reduces the yaw angle change due to the transient disturbance by the yaw angle F / B control, and the yaw angle integral value (lateral position change) due to the steady disturbance is changed to the horizontal position. Reduction by F / B control can improve both vehicle stability against transient and steady disturbances.
Further, the stability control of the first embodiment is such that the driver is not aware of the vehicle behavior caused by the control (giving the disturbance suppression command turning angle) and does not disturb the vehicle behavior change caused by the driver's steering. This is possible without limiting the driver to be aware that the stability control is being performed because the change in the self-aligning torque caused by the control is not reflected in the steering reaction force. As a result, it is possible to simulate the behavior of a vehicle having body specifications that are excellent in stability against disturbance.
In the lateral position F / B control, the lateral position F / B gain for obtaining the repulsive force according to the lateral position is set to a value smaller than the yaw angle F / B gain. As described above, the yaw angle F / B control is required to converge the yaw angle before the driver feels a change in yaw angle due to a transient disturbance. B control is required to stop increasing the lateral position change, and it takes time for the lateral position to change due to the accumulation of the yaw angle integral value. Is not necessary. In addition, if the lateral position F / B gain is increased, the control amount fluctuates greatly depending on the magnitude of the disturbance, giving the driver a sense of incongruity.
 [横力オフセット部]
  図11は、横力オフセット部34の制御ブロック図である。
  曲率演算部(曲率検出手段,センサ)34aは、前方注視点での白線の曲率を演算する。
  上下限リミッタ34bは、車速に上下限リミッタ処理を施す。
  SATゲイン演算部34cは、リミッタ処理後の車速に基づき、車速に応じたSATゲインを演算する。SATゲインは、車速が高いほど大きなゲインとなる特性とし、上限を設定する。
  乗算器34dは、SATゲインに曲率を乗じて横力オフセット量を求める。
  リミッタ処理部34eは、横力オフセット量の最大値および変化率の上限を制限する。例えば、最大値は1,000N、変化率の上限は600N/sとする。尚、リミッタ処理部34eにおける横力オフセット量の制限については後で詳細に説明する。
[Side force offset part]
FIG. 11 is a control block diagram of the lateral force offset unit 34.
The curvature calculation unit (curvature detection means, sensor) 34a calculates the curvature of the white line at the front gazing point.
The upper / lower limiter 34b performs upper / lower limiter processing on the vehicle speed.
The SAT gain calculation unit 34c calculates the SAT gain according to the vehicle speed based on the vehicle speed after the limiter process. The SAT gain has a characteristic that increases as the vehicle speed increases, and an upper limit is set.
The multiplier 34d obtains the lateral force offset amount by multiplying the SAT gain by the curvature.
The limiter processing unit 34e limits the maximum value of the lateral force offset amount and the upper limit of the change rate. For example, the maximum value is 1,000 N, and the upper limit of the change rate is 600 N / s. The limitation on the lateral force offset amount in the limiter processing unit 34e will be described later in detail.
 [曲率に応じた反力オフセット制御作用]
  曲率に応じた反力オフセット制御は、白線の曲率が大きいほど大きな横力オフセット量を求め、タイヤ横力から減算する。これにより、SAT演算部35で演算されるタイヤ横力に応じた操舵反力トルク、すなわち、セルフアライニングトルクに応じた操舵反力トルクを表す操舵反力特性は、図12に示すように、白線の曲率が大きくなるほど、セルフアライニングトルクと同一符号方向へオフセットされる。なお、図12は右カーブの場合であり、左カーブの場合は図12と反対方向にオフセットされる。
[Reaction force offset control according to curvature]
The reaction force offset control according to the curvature obtains a larger lateral force offset amount as the curvature of the white line is larger, and subtracts it from the tire lateral force. Thereby, the steering reaction force torque corresponding to the tire lateral force calculated by the SAT calculation unit 35, that is, the steering reaction force characteristic indicating the steering reaction force torque corresponding to the self-aligning torque, is shown in FIG. As the curvature of the white line increases, the self-aligning torque is offset in the same sign direction. Note that FIG. 12 shows the case of the right curve, and the case of the left curve is offset in the opposite direction to FIG.
 従来、操舵部と転舵部とが機械的に切り離されたSBWシステムでは、コンベンショナルな操舵装置におけるセルフアライニングトルクに応じた操舵反力を模擬する操舵反力特性を設定し、当該操舵反力特性に基づいてステアリングホイールに操舵反力を付与しており、このとき、ステアリングホイールの操舵角とドライバの操舵トルクとの関係は、図13に示すような特性Aとなる。すなわち、操舵角の絶対値が大きいほど操舵トルクの絶対値は大きくなり、操舵角の絶対値が小さいときは大きいときよりも操舵角の変化量に対する操舵トルクの変化量が大きくなる。 Conventionally, in the SBW system in which the steering unit and the steering unit are mechanically separated, a steering reaction force characteristic that simulates the steering reaction force according to the self-aligning torque in the conventional steering device is set, and the steering reaction force A steering reaction force is applied to the steering wheel based on the characteristics. At this time, the relationship between the steering angle of the steering wheel and the steering torque of the driver is a characteristic A as shown in FIG. That is, the larger the absolute value of the steering angle, the larger the absolute value of the steering torque. When the absolute value of the steering angle is small, the amount of change of the steering torque with respect to the amount of change of the steering angle becomes larger than when the absolute value of the steering angle is large.
 ここで、旋回中にドライバが進路修正のために保舵トルクを変化させる場合を考える。図13において、ドライバが保舵トルクT1で操舵角θ1を保持した状態から、保舵トルクをT2まで減少させると、操舵角はθ2となり、操舵角の減少によって前輪5L,5Rの転舵角は小さくなる。このとき、上述したSBWシステムにおける操舵反力特性により、カーブの曲率が大きいほど保舵トルクの変化に対して操舵角は大きく変動する。つまり、カーブの曲率が大きいほど操舵トルクに対する車両の感度が高くなるため、進路修正が困難であるという問題があった。 Here, consider the case where the driver changes the steering torque to correct the course during turning. In FIG. 13, when the driver maintains the steering angle θ 1 with the steering torque T 1 and reduces the steering torque to T 2 , the steering angle becomes θ 2 , and the front wheels 5L and 5R are reduced by the reduction of the steering angle. The turning angle becomes smaller. At this time, due to the steering reaction force characteristic in the SBW system described above, the steering angle fluctuates more greatly with respect to the change in the holding torque as the curvature of the curve increases. In other words, the greater the curvature of the curve, the higher the sensitivity of the vehicle to the steering torque, making it difficult to correct the course.
 これに対し、実施例1の曲率に応じた反力オフセット制御では、白線の曲率が大きいほどセルフアライニングトルクに応じた操舵反力トルクを表す操舵反力特性をセルフアライニングトルクと同一符号方向へオフセットすることで、操舵角と操舵トルクとの関係を表す特性は、図14に示すように操舵角と同一符号方向へオフセットされ、特性Aから特性Bへと変化する。これにより、白線の曲率が大きいほど保舵トルクの変化量に対する操舵角の変化量が小さくなるため、ドライバが保舵トルクをT4まで減少させ、保舵トルクの減少量ΔT3-4が図13に示した従来技術の減少量ΔT1-2と同一の場合であったとしても、操舵角の減少量Δθ1-4は従来技術の減少量Δθ1-2よりも小さくなる。つまり、カーブの曲率が大きいほど保舵トルクの変化に対する操舵角の変動を小さくでき、操舵トルクに対する車両の感度を低くできるため、車両の挙動変化を緩やかとなり、ドライバによる進路修正の容易化を図ることができる。また、操舵角θを維持するための保舵トルクT3(<T1)を従来技術よりも小さくできるため、旋回時におけるドライバの操舵負担を軽減できる。 On the other hand, in the reaction force offset control according to the curvature of the first embodiment, the steering reaction force characteristic representing the steering reaction force torque corresponding to the self-aligning torque becomes the same sign direction as the self-aligning torque as the curvature of the white line is larger. As shown in FIG. 14, the characteristic representing the relationship between the steering angle and the steering torque is offset in the same sign direction as the steering angle, and changes from characteristic A to characteristic B. Thus, since the amount of change in the steering angle with respect to the change amount of the higher steering holding torque is larger curvature of the white line is reduced, the driver reduces the fixed steering torque to T 4, the reduction amount [Delta] T 3-4 of steering holding torque Figure Even if it is the same as the decrease amount ΔT 1-2 of the prior art shown in FIG. 13, the decrease amount Δθ 1-4 of the steering angle is smaller than the decrease amount Δθ 1-2 of the prior art. In other words, the greater the curvature of the curve, the smaller the fluctuation of the steering angle with respect to the change in the steering torque and the lower the sensitivity of the vehicle to the steering torque, so that the behavior change of the vehicle becomes gradual and the course correction by the driver is facilitated. be able to. Further, since the steering torque T 3 (<T 1 ) for maintaining the steering angle θ 1 can be made smaller than that of the prior art, the driver's steering burden during turning can be reduced.
 従来、旋回時におけるドライバの操舵負担軽減を目的とし、白線の曲率が大きいほど操舵反力特性の傾きを小さくする技術は知られているが、当該従来技術では、曲率が大きいほど保舵トルクの変化に対する操舵角の変動が大きくなるため、操舵トルクに対する車両の感度が高くなってしまう。つまり、操舵反力特性を白線の曲率に応じてセルフアライニングトルクと同一方向へオフセットすることで、旋回時におけるドライバの操舵負担軽減と進路修正の容易化との両立を実現できる。 Conventionally, a technique for reducing the slope of the steering reaction force characteristic as the curvature of the white line is large is known for the purpose of reducing the driver's steering burden during turning, but in the conventional technique, the steering torque is reduced as the curvature increases. Since the variation of the steering angle with respect to the change becomes large, the sensitivity of the vehicle to the steering torque becomes high. That is, by offsetting the steering reaction force characteristic in the same direction as the self-aligning torque according to the curvature of the white line, it is possible to realize both reduction of the driver's steering burden during turning and ease of course correction.
 [操舵反力トルクオフセット部]
  図15は、操舵反力トルクオフセット部36の制御ブロック図である。
  ヨー角演算部36aは、前方注視点でのヨー角を演算する。カメラ17により撮影された走行路の映像に基づいてヨー角を演算することで、簡単かつ高精度にヨー角を検出できる。
  横位置演算部36bは、前方注視点での左右白線に対する横位置および現在位置での左右白線に対する横位置をそれぞれ演算する。ここで、横位置演算部36bは、自車が白線を越えて隣の走行車線に移った場合、すなわち、レーンチェンジが行われた場合、現在位置での左右白線に対する横位置を入れ替える。つまり、白線到達前の左白線に対する横位置を白線到達後の右白線に対する横位置とし、白線到達前の右白線に対する横位置を白線到達後の左白線に対する横位置とする。なお、車線幅が異なる走行車線にレーンチェンジした場合には、レーンチェンジ後の走行車線の車線幅W2をレーンチェンジ前の走行車線の車線幅W1で除した値W2/W1を入れ替えた横位置に乗じて横位置を補正する。ここで、各走行車線の車線幅情報は、ナビゲーションシステム24から取得する。
  逸脱余裕時間に応じた反力演算部39は、車速とヨー角と前方注視点での左右白線に対する横位置とに基づき、逸脱余裕時間に応じた反力を演算する。逸脱余裕時間に応じた反力演算部39の詳細については後述する。
  横位置に応じた反力演算部40は、現在位置での左右白線に対する横位置に基づき、横位置に応じた反力を演算する。横位置に応じた反力演算部40の詳細については後述する。
  反力選択部36cは、逸脱余裕時間に応じた反力と横位置に応じた反力のうち絶対値が大きな方を操舵反力トルクオフセット量として選択する。
  リミッタ処理部36dは、操舵反力トルクオフセット量の最大値および変化率の上限を制限する。例えば、最大値は2Nm、変化率の上限は10Nm/sとする。
[Steering reaction force torque offset part]
FIG. 15 is a control block diagram of the steering reaction force torque offset unit 36.
The yaw angle calculator 36a calculates the yaw angle at the forward gazing point. By calculating the yaw angle based on the image of the travel path taken by the camera 17, the yaw angle can be detected easily and with high accuracy.
The horizontal position calculation unit 36b calculates a horizontal position with respect to the left and right white lines at the forward gazing point and a horizontal position with respect to the left and right white lines at the current position. Here, when the own vehicle moves over the white line and moves to the adjacent traveling lane, that is, when a lane change is performed, the horizontal position calculation unit 36b switches the horizontal position with respect to the left and right white lines at the current position. That is, the horizontal position with respect to the left white line before reaching the white line is set as the horizontal position with respect to the right white line after reaching the white line, and the horizontal position with respect to the right white line before reaching the white line is set as the horizontal position with respect to the left white line after reaching the white line. If a lane change is made to a lane with a different lane width, the value W 2 / W 1 obtained by dividing the lane width W 2 of the lane after the lane change by the lane width W 1 of the lane before the lane change is replaced. The horizontal position is corrected by multiplying the horizontal position. Here, the lane width information of each traveling lane is acquired from the navigation system 24.
The reaction force calculation unit 39 corresponding to the departure allowance time calculates the reaction force corresponding to the departure allowance time based on the vehicle speed, the yaw angle, and the lateral position with respect to the left and right white lines at the front gazing point. Details of the reaction force calculation unit 39 according to the departure allowance time will be described later.
The reaction force calculation unit 40 according to the lateral position calculates a reaction force according to the lateral position based on the lateral position with respect to the left and right white lines at the current position. Details of the reaction force calculation unit 40 according to the lateral position will be described later.
The reaction force selection unit 36c selects, as the steering reaction force torque offset amount, the larger absolute value among the reaction force according to the departure allowance time and the reaction force according to the lateral position.
The limiter processing unit 36d limits the maximum value of the steering reaction force torque offset amount and the upper limit of the change rate. For example, the maximum value is 2 Nm, and the upper limit of the change rate is 10 Nm / s.
 図16は、逸脱余裕時間に応じた反力演算部39の制御ブロック図である。
  乗算器39aは、ヨー角に車速を乗じて車両の横速度を求める。
  除算器39bは、前方注視点での左白線に対する横位置を横速度で除して左白線に対する逸脱余裕時間を求める。
  除算器39cは、前方注視点での右白線に対する横位置を横速度で除して右白線に対する逸脱余裕時間を求める。
  逸脱余裕時間選択部39dは、左右白線に対する逸脱余裕時間のうち短い方を逸脱余裕時間として選択する。
  逸脱余裕時間に応じた反力演算部39eは、逸脱余裕時間に基づき、逸脱余裕時間に応じた反力を演算する。逸脱余裕時間に応じた反力は、逸脱余裕時間に反比例(逸脱余裕時間の逆数に比例)し、3秒以上でほぼゼロとなる特性を有する。
FIG. 16 is a control block diagram of the reaction force calculation unit 39 according to the departure allowance time.
The multiplier 39a obtains the lateral speed of the vehicle by multiplying the yaw angle by the vehicle speed.
The divider 39b divides the lateral position with respect to the left white line at the forward gazing point by the lateral speed to obtain a deviation margin time with respect to the left white line.
The divider 39c divides the lateral position with respect to the right white line at the forward gazing point by the lateral speed to obtain a deviation margin time with respect to the right white line.
The deviation margin time selection unit 39d selects the shorter of the deviation margin times for the left and right white lines as the deviation margin time.
The reaction force calculator 39e according to the departure allowance time calculates a reaction force according to the departure allowance time based on the departure allowance time. The reaction force according to the deviation margin time is inversely proportional to the deviation margin time (proportional to the reciprocal of the deviation margin time), and has a characteristic of almost zero after 3 seconds.
 図17は、横位置に応じた反力演算部40の制御ブロック図である。
  減算器40aは、あらかじめ設定された目標左横位置(例えば、90cm)から左車線に対する横位置を減じて左車線に対する横位置偏差を求める。
  減算器40bは、あらかじめ設定された目標右横位置(例えば、90cm)から右車線に対する横位置を減じて右車線に対する横位置偏差を求める。
  横位置偏差選択部40cは、左右車線に対する横位置偏差のうち大きな方を横位置偏差として選択する。
  横位置偏差に応じた反力演算部40dは、横位置偏差に基づき、横位置に応じた反力を演算する。横位置に応じた反力は、横位置偏差が大きいほど大きくなる特性とし、上限を設定する。
FIG. 17 is a control block diagram of the reaction force calculation unit 40 according to the lateral position.
The subtractor 40a obtains a lateral position deviation with respect to the left lane by subtracting the lateral position with respect to the left lane from a preset target left lateral position (for example, 90 cm).
The subtractor 40b subtracts the lateral position with respect to the right lane from a preset target right lateral position (for example, 90 cm) to obtain a lateral position deviation with respect to the right lane.
The lateral position deviation selection unit 40c selects the larger one of the lateral position deviations with respect to the left and right lanes as the lateral position deviation.
The reaction force calculation unit 40d according to the lateral position deviation calculates a reaction force according to the lateral position based on the lateral position deviation. The reaction force according to the lateral position has a characteristic that increases as the lateral position deviation increases, and an upper limit is set.
 [横位置に応じた反力オフセット制御作用]
  横位置に応じた反力オフセット制御は、横位置に応じた反力を操舵反力トルクオフセット量として操舵反力トルクに加算する。これにより、セルフアライニングトルクに応じた操舵反力トルクを表す操舵反力特性は、図18に示すように、白線までの距離が短くなるほど操舵反力トルクの絶対値が大きくなる方向へオフセットされる。なお、図18は右車線に近い場合であり、左車線に近い場合は図18と反対方向にオフセットされる。
[Reaction force offset control action according to lateral position]
In the reaction force offset control according to the lateral position, the reaction force according to the lateral position is added to the steering reaction force torque as a steering reaction force torque offset amount. As a result, the steering reaction force characteristic representing the steering reaction force torque corresponding to the self-aligning torque is offset in a direction in which the absolute value of the steering reaction force torque increases as the distance to the white line decreases, as shown in FIG. The FIG. 18 shows a case where the vehicle is close to the right lane. When the vehicle is close to the left lane, the vehicle is offset in the opposite direction to FIG.
 ここで、従来の操舵反力制御において、ドライバの不意な右方向への切り増し操作により車両の走行位置が右側にずれ、その後ドライバが修正操舵によって走行位置を走行車線中央付近に戻す場合を考える。ドライバが不意な操作を行ったときの操舵角と操舵トルクを、図19の特性A上の点P1の位置とする。特性Aは、図13と同様、コンベンショナルな操舵装置を模擬した操舵反力特性を設定したときの操舵角と操舵トルクとの関係を表す特性とする。この状態から走行位置を走行車線中央付近に戻すためには、前輪を左に転舵させる必要が有るため、ドライバは操舵角中立位置への切り戻し操作に続けて、操舵角中立位置からの切り増し操作を行い、ステアリングホイールを狙った角度θ5に合わせる。このとき、上記従来技術では、操舵角中立位置(操舵角ゼロ点)と操舵トルク中立位置(操舵トルクゼロ点)とが一致しているため、操舵角中立位置までは操舵トルクを減少させ、操舵角中立位置を超えたら操舵トルクを増加させる必要がある。つまり、操舵角中立位置をまたぐ修正操舵を行う場合、操舵トルクの符号が反転し、ドライバが力をコントロールする方向が切り替わると共に、操舵トルク中立位置付近は他の操舵角領域と比較して操舵トルクの変化量に対する操舵角の変化量が著しく小さいため、ドライバの操舵負担が大きく、ステアリングホイールを狙った角度θ5にコントロールすることが困難である。これにより、車両の走行位置がオーバーシュートしやすくなることで、修正操舵量の増大を招くという問題があった。 Here, in the conventional steering reaction force control, a case is considered in which the driving position of the vehicle is shifted to the right side due to the driver's unexpected increase in the right direction, and then the driver returns the driving position to the vicinity of the center of the driving lane by correction steering. . The steering angle and steering torque when the driver performs an unexpected operation are set as the position of point P 1 on the characteristic A in FIG. The characteristic A is a characteristic representing the relationship between the steering angle and the steering torque when the steering reaction force characteristic simulating a conventional steering device is set, as in FIG. In order to return the driving position from this state to the vicinity of the center of the driving lane, it is necessary to steer the front wheels to the left, so the driver switches from the steering angle neutral position to the steering angle neutral position following the switch back operation to the steering angle neutral position. increases do, match the angle θ 5 aimed at the steering wheel. At this time, in the above prior art, since the steering angle neutral position (steering angle zero point) and the steering torque neutral position (steering torque zero point) coincide, the steering torque is reduced to the steering angle neutral position, and the steering angle If the neutral position is exceeded, the steering torque must be increased. In other words, when corrective steering is performed across the steering angle neutral position, the sign of the steering torque is reversed, the direction in which the driver controls the force is switched, and the steering torque near the steering torque neutral position is compared with other steering angle regions. Since the amount of change in the steering angle with respect to the amount of change is extremely small, the driver's steering burden is large, and it is difficult to control the steering wheel to the angle θ 5 . As a result, the traveling position of the vehicle is likely to overshoot, resulting in an increase in the corrected steering amount.
 これに対し、実施例1の横位置に応じた反力オフセット制御では、白線までの距離が短いほどセルフアライニングトルクに応じた操舵反力トルクを操舵反力トルクの絶対値が大きくなる方向へオフセットすることで、操舵角と操舵トルクとの関係を表す特性は、図20に示すように、操舵トルクの絶対値が大きくなる方向へオフセットされ、白線までの距離が短くなるに従い特性Aから特性Cへと連続的に変化する。このとき、操舵角を維持するためには、操舵トルクを増やす必要があり、操舵トルクが一定であれば、ステアリングホイール6が少しずつ操舵角中立位置に戻されるため(点P1→点P2)、ドライバの不意な切り増し操作によって車両の走行位置が右側にずれるのを抑制できる。一方、ドライバが操舵角を維持した場合、操舵角と操舵トルクは点P1から点P3へと移動する。この状態からドライバが修正操舵を行う場合、特性Cでは操舵トルク中立位置が操舵角中立位置よりも切り増し側へオフセットされているため、操舵角中立位置からの切り増し操作時において、操舵トルク中立位置に達するまでの間、操舵トルクの符号は反転しない。よって、ドライバは操舵トルクを減少させ、ステアリングホイール6が狙いの角度となったときにステアリングホイール6の回転を止めるだけで、前輪5L,5Rの転舵角をコントロールできる。つまり、実施例1の横位置に応じた反力オフセット制御は、ドライバが力をコントロールする方向が切り替わりにくいため、ドライバの修正操舵を容易化できる。この結果、車両の走行位置がオーバーシュートしにくくなるため、修正操舵量を低減できる。 In contrast, in the reaction force offset control according to the lateral position of the first embodiment, the steering reaction force torque according to the self-aligning torque is increased in the direction in which the absolute value of the steering reaction force torque increases as the distance to the white line is shorter. The characteristic representing the relationship between the steering angle and the steering torque by the offset is offset from the characteristic A as the distance to the white line becomes shorter as the absolute value of the steering torque is increased as shown in FIG. Changes continuously to C. At this time, in order to maintain the steering angle, it is necessary to increase the steering torque, and if the steering torque is constant, the steering wheel 6 is gradually returned to the steering angle neutral position (point P 1 → point P 2 ), It is possible to prevent the vehicle travel position from shifting to the right side due to the driver's unexpected increase operation. On the other hand, when the driver maintains the steering angle, the steering angle and the steering torque move from the point P 1 to the point P 3 . When the driver performs corrective steering from this state, in the characteristic C, the steering torque neutral position is offset from the steering angle neutral position to the additional side, so the steering torque neutral position is increased when the steering angle is increased from the steering angle neutral position. The sign of the steering torque is not reversed until the position is reached. Therefore, the driver can control the turning angle of the front wheels 5L and 5R only by reducing the steering torque and stopping the rotation of the steering wheel 6 when the steering wheel 6 reaches the target angle. In other words, the reaction force offset control according to the lateral position of the first embodiment can facilitate the driver's correction steering because the direction in which the driver controls the force is difficult to switch. As a result, the travel position of the vehicle is less likely to overshoot, and the correction steering amount can be reduced.
 従来、ドライバの不意な操作によって走行位置がずれるのを抑制することを目的とし、白線に近付くほど操舵反力を大きくする技術は知られているが、当該従来技術では、白線に近づくほどステアリングホイールを重くするだけであって、操舵反力特性における操舵トルク中立位置は常に操舵角中立位置と一致しているため、操舵角中立位置をまたぐ修正操舵では、操舵トルクの符号が反転し、ドライバの操舵負担は軽減されない。つまり、白線までの距離が短いほどセルフアライニングトルクに応じた操舵反力トルクを操舵反力トルクの絶対値が大きくなる方向へオフセットすることで、走行位置のずれ抑制とドライバの操舵負担軽減との両立を実現できる。 Conventionally, a technique for increasing the steering reaction force as it approaches the white line has been known for the purpose of suppressing the shift of the driving position due to an unexpected operation by the driver. Since the steering torque neutral position in the steering reaction force characteristic always coincides with the steering angle neutral position, the sign of the steering torque is reversed in the correction steering across the steering angle neutral position, The steering burden is not reduced. In other words, as the distance to the white line is shorter, the steering reaction force torque corresponding to the self-aligning torque is offset in the direction in which the absolute value of the steering reaction force torque is increased, thereby suppressing the deviation of the driving position and reducing the driver's steering burden. Can be realized.
 また、実施例1の横位置に応じた反力オフセット制御では、白線までの距離が短いほどオフセット量を大きくしているため、操舵トルク中立位置は、白線までの距離が短いほど操舵角中立位置からより離れた位置へオフセットされる。ドライバが車両の走行位置を走行車線中央付近まで戻す修正操舵を行う場合、白線に近いほど操舵角中立位置からの切り増し操作量を多くする必要がある。このとき、操舵角中立位置に対する操舵トルク中立位置のオフセット量が小さいと、ステアリングホイールが狙いの角度となる前に操舵トルクが中立位置を越えて操舵トルクの符号が反転する可能性がある。よって、白線までの距離が短いほどオフセット量を大きくすることで、操舵トルクが中立位置を越えるのを抑制できる。 In the reaction force offset control according to the lateral position of the first embodiment, the offset amount is increased as the distance to the white line is shorter. Therefore, the steering torque neutral position is the steering angle neutral position as the distance to the white line is shorter. Is offset further away from When the driver performs corrective steering to return the vehicle travel position to the vicinity of the center of the travel lane, the closer the white line is, the greater the amount of additional operation from the steering angle neutral position is required. At this time, if the offset amount of the steering torque neutral position with respect to the steering angle neutral position is small, the steering torque may exceed the neutral position and the sign of the steering torque may be reversed before the steering wheel reaches the target angle. Therefore, it is possible to suppress the steering torque from exceeding the neutral position by increasing the offset amount as the distance to the white line is shorter.
 実施例1の横位置に応じた反力オフセット制御において、横位置演算部36bは、自車が白線に到達したとき、現在位置での左右白線に対する横位置を入れ替える。横位置に応じた反力オフセット制御では、自車が走行車線中央付近から遠ざかるほど操舵反力を大きくすることで自車が走行車線中央付近に戻りやすくしている。つまり、ヨー角積分値(横位置変化)を外乱とみなし、車両をヨー角積分値が無くなる方向へ誘導するように操舵反力を制御している。このため、レーンチェンジが行われた場合、ヨー角積分値をリセットする必要がある。仮にヨー角積分値をリセットしない場合、レーンチェンジ後もレーンチェンジ前の走行車線中央付近に車両を戻すための操舵反力が作用し続けるため、ドライバの操作が阻害されるからである。なお、単に積分値をゼロとするのみでは、レーンチェンジ後の走行車線中央付近に車両を誘導することができない。 In the reaction force offset control according to the lateral position of the first embodiment, the lateral position calculation unit 36b switches the lateral position with respect to the left and right white lines at the current position when the host vehicle reaches the white line. In the reaction force offset control according to the lateral position, the host vehicle is more likely to return to the vicinity of the center of the travel lane by increasing the steering reaction force as the host vehicle is further away from the vicinity of the center of the travel lane. In other words, the yaw angle integral value (lateral position change) is regarded as a disturbance, and the steering reaction force is controlled so as to guide the vehicle in a direction in which the yaw angle integral value disappears. For this reason, when a lane change is performed, it is necessary to reset the yaw angle integral value. If the yaw angle integral value is not reset, the steering reaction force for returning the vehicle to the vicinity of the center of the traveling lane before the lane change continues to act even after the lane change, and the driver's operation is hindered. Note that the vehicle cannot be guided near the center of the travel lane after the lane change by simply setting the integral value to zero.
 そこで、実施例1では、自車が白線に到達した場合には、ドライバの意図的な操作とみなせるため、その場合は現在位置での左右白線に対する横位置を入れ替える、換言すると、ヨー角積分値の符号を反転させることにより、自車を誘導する位置をレーンチェンジ前の走行車線中央付近からレーンチェンジ後の走行車線中央付近に切り替え、レーンチェンジ後の走行車線中央付近に自車を誘導するための操舵反力を生成できる。このとき、レーンチェンジ前の走行車線の車線幅W1に対するレーンチェンジ後の走行車線の車線幅W2の比率W2/W1を考慮するため、正確な横位置を設定でき、自車を走行車線中央付近に誘導するための最適なオフセット量を設定できる。 Therefore, in the first embodiment, when the vehicle reaches the white line, it can be regarded as a driver's intentional operation. In this case, the lateral position with respect to the left and right white lines at the current position is switched. In order to guide the vehicle to the center of the lane after the lane change by switching the position where the vehicle is guided from the center of the lane before the lane change to the center of the lane after the lane change. The steering reaction force can be generated. At this time, since the ratio W 2 / W 1 of the lane width W 2 of the lane after the lane change to the lane width W 1 of the lane before the lane change is taken into account, an accurate lateral position can be set and the vehicle is driven You can set an optimal offset for guiding to the vicinity of the lane center.
 [逸脱余裕時間に応じた反力オフセット制御作用]
  逸脱余裕時間に応じた反力オフセット制御は、逸脱余裕時間に応じた反力を操舵反力トルクオフセット量として操舵反力トルクに加算する。これにより、セルフアライニングトルクに応じた操舵反力トルクを表す操舵反力特性は、図18に示したように、逸脱余裕時間が短くなるほど操舵反力トルクの絶対値が大きくなる方向へオフセットされる。なお、図18は右車線に近い場合であり、左車線に近い場合は図18と反対方向にオフセットされる。
[Reaction force offset control action according to deviation margin time]
In the reaction force offset control according to the departure allowance time, the reaction force according to the departure allowance time is added to the steering reaction force torque as the steering reaction force torque offset amount. As a result, the steering reaction force characteristic representing the steering reaction force torque corresponding to the self-aligning torque is offset in a direction in which the absolute value of the steering reaction force torque increases as the deviation margin time decreases, as shown in FIG. The FIG. 18 shows a case where the vehicle is close to the right lane. When the vehicle is close to the left lane, the vehicle is offset in the opposite direction to FIG.
 このため、操舵角と操舵トルクとの関係を表す特性は、図20に示したように、操舵トルクの絶対値が大きくなる方向へオフセットされ、逸脱余裕時間が短くなるに従い特性Aから特性Cへと連続的に変化する。このとき、操舵角を維持するためには、操舵トルクを増やす必要があり、操舵トルクが一定であれば、ステアリングホイール6が少しずつ操舵角中立位置に戻されるため(点P1→点P2)、ドライバの不意な切り増し操作によって車両の走行位置が右側にずれるのを抑制できる。一方、ドライバが操舵角を維持した場合、操舵角と操舵トルクは点P1から点P3へと移動する。この状態からドライバが修正操舵を行う場合、特性Cでは操舵トルク中立位置が操舵角中立位置よりも切り増し側へオフセットされているため、操舵角中立位置からの切り増し操作時において、操舵トルク中立位置に達するまでの間、操舵トルクの符号は反転しない。よって、ドライバは操舵トルクを減少させ、ステアリングホイール6が狙いの角度となったときにステアリングホイール6の回転を止めるだけで、前輪5L,5Rの転舵角をコントロールできる。つまり、実施例1の逸脱余裕時間に応じた反力オフセット制御は、ドライバが力をコントロールする方向が切り替わりにくいため、ドライバの修正操舵を容易化できる。この結果、車両の走行位置がオーバーシュートしにくくなるため、修正操舵量を低減できる。 Therefore, the characteristic representing the relationship between the steering angle and the steering torque is offset in the direction in which the absolute value of the steering torque increases as shown in FIG. 20, and from characteristic A to characteristic C as the deviation margin time becomes shorter. And change continuously. At this time, in order to maintain the steering angle, it is necessary to increase the steering torque, and if the steering torque is constant, the steering wheel 6 is gradually returned to the steering angle neutral position (point P 1 → point P 2 ), It is possible to prevent the vehicle travel position from shifting to the right side due to the driver's unexpected increase operation. On the other hand, when the driver maintains the steering angle, the steering angle and the steering torque move from the point P 1 to the point P 3 . When the driver performs corrective steering from this state, in the characteristic C, the steering torque neutral position is offset from the steering angle neutral position to the additional side, so the steering torque neutral position is increased when the steering angle is increased from the steering angle neutral position. The sign of the steering torque is not reversed until the position is reached. Therefore, the driver can control the turning angle of the front wheels 5L and 5R only by reducing the steering torque and stopping the rotation of the steering wheel 6 when the steering wheel 6 reaches the target angle. That is, the reaction force offset control according to the departure allowance time according to the first embodiment can facilitate the driver's correction steering because the direction in which the driver controls the force is difficult to switch. As a result, the travel position of the vehicle is less likely to overshoot, and the correction steering amount can be reduced.
 また、実施例1の逸脱余裕時間に応じた反力オフセット制御では、逸脱余裕時間が短いほどオフセット量を大きくしているため、操舵トルク中立位置は、逸脱余裕時間が短いほど操舵角中立位置からより離れた位置へオフセットされる。ドライバが車両の走行位置を走行車線中央付近まで戻す修正操舵を行う場合、逸脱余裕時間が短いほど白線に近い可能性が高く、白線に近いほど操舵角中立位置からの切り増し操作量を多くする必要がある。このとき、操舵角中立位置に対する操舵トルク中立位置のオフセット量が小さいと、ステアリングホイールが狙いの角度となる前に操舵トルクが中立位置を越えて操舵トルクの符号が反転する可能性がある。よって、白線までの距離が短いほどオフセット量を大きくすることで、操舵トルクが中立位置を越えるのを抑制できる。 In the reaction force offset control according to the departure allowance time of the first embodiment, the offset amount is increased as the departure allowance time is shorter. Therefore, the steering torque neutral position is changed from the steering angle neutral position as the departure allowance time is shorter. Offset to a more distant position. When the driver performs corrective steering to return the vehicle travel position to near the center of the travel lane, the shorter the deviation margin time, the closer to the white line, and the closer to the white line, the greater the amount of operation to increase from the steering angle neutral position. There is a need. At this time, if the offset amount of the steering torque neutral position with respect to the steering angle neutral position is small, the steering torque may exceed the neutral position and the sign of the steering torque may be reversed before the steering wheel reaches the target angle. Therefore, it is possible to suppress the steering torque from exceeding the neutral position by increasing the offset amount as the distance to the white line is shorter.
 [横位置および逸脱余裕時間に応じた反力オフセット制御の併用効果]
  操舵反力制御部20では、操舵反力トルクオフセット部36において、逸脱余裕時間に応じた反力と横位置に応じた反力のうち絶対値が大きな方を操舵反力トルクオフセット量として選択し、加算器20cにおいて、操舵反力トルクに操舵反力トルクオフセット量を加算する。これにより、逸脱余裕時間または横位置に応じて操舵反力特性が操舵反力トルクの絶対値が大きくなる方向へオフセットされる。
  逸脱余裕時間に応じた反力オフセット制御では、自車と白線とが平行である場合、すなわち、ヨー角がゼロである場合、逸脱余裕時間に応じた反力はゼロである。このため、自車が白線に近い位置であっても、ヨー角が小さい場合には、僅かな反力しか出すことができない。これに対し、横位置に応じた反力オフセット制御では、白線までの距離に比例して反力(横位置に応じた反力)を生成するため、白線までの距離が短くなるほど大きな反力を出すことができ、自車を走行車線中央付近に戻しやすくすることができる。
[Combination effect of reaction force offset control according to lateral position and deviation margin time]
In the steering reaction force control unit 20, the steering reaction force torque offset unit 36 selects the reaction force corresponding to the deviation margin time and the reaction force corresponding to the lateral position having the larger absolute value as the steering reaction force torque offset amount. The adder 20c adds the steering reaction torque offset amount to the steering reaction torque. As a result, the steering reaction force characteristic is offset in a direction in which the absolute value of the steering reaction force torque is increased in accordance with the departure allowance time or the lateral position.
In the reaction force offset control according to the departure allowance time, when the vehicle and the white line are parallel, that is, when the yaw angle is zero, the reaction force according to the departure allowance time is zero. For this reason, even if the vehicle is near the white line, if the yaw angle is small, only a slight reaction force can be produced. On the other hand, in the reaction force offset control according to the horizontal position, a reaction force (reaction force according to the horizontal position) is generated in proportion to the distance to the white line, so a larger reaction force as the distance to the white line becomes shorter. And the vehicle can be easily returned to the vicinity of the center of the traveling lane.
 一方、横位置に応じた反力オフセット制御では、自車が走行車線中央付近にある場合、横位置に応じた反力はゼロである。このため、走行車線中央付近であっても、ヨー角が大きく、さらに車速が高いとき場合には、短時間で白線まで到達するのに対し、操舵反力を応答良く増大させることが難しい。これに対し、逸脱余裕時間に応じた反力オフセット制御では、逸脱余裕時間に応じて反力(逸脱余裕時間に応じた反力)を生成すること、および当該反力は逸脱余裕時間が3秒以下になると急激に立ち上がる特性であることから、短時間で白線まで到達する場合であっても、操舵反力を応答良く増大させて車線逸脱を抑制できる。
  よって、逸脱余裕時間に応じた反力オフセット制御と横位置に応じた反力オフセット制御を併用することにより、白線までの距離に応じて安定的な反力を付与しつつ、車線逸脱を効果的に抑制できる。このとき、逸脱余裕時間に応じた反力と横位置に応じた反力のうち絶対値が大きな方を用いることで、常に必要とされる最適な操舵反力を付与できる。
On the other hand, in the reaction force offset control according to the lateral position, when the vehicle is near the center of the traveling lane, the reaction force according to the lateral position is zero. For this reason, even in the vicinity of the center of the traveling lane, when the yaw angle is large and the vehicle speed is high, it is difficult to increase the steering reaction force with good response while reaching the white line in a short time. In contrast, in the reaction force offset control according to the departure allowance time, a reaction force (reaction force according to the departure allowance time) is generated according to the departure allowance time, and the reaction force has a departure allowance time of 3 seconds. Since it is a characteristic that suddenly rises below, even if the white line is reached in a short time, the steering reaction force can be increased with good response to suppress lane departure.
Therefore, by using the reaction force offset control according to the departure allowance time and the reaction force offset control according to the lateral position, it is possible to effectively deviate from the lane while giving a stable reaction force according to the distance to the white line. Can be suppressed. At this time, the optimum steering reaction force that is always required can be applied by using the reaction force corresponding to the departure allowance time and the reaction force corresponding to the lateral position having the larger absolute value.
 [横力オフセット部のリミッタ処理について]
 次に、横力オフセット部34におけるリミッタ処理部34eの詳細について説明する。図21は実施例1の横力オフセット部におけるリミッタ処理部内の制御構成を表すブロック図である。リミッタ処理部34eは、曲率が予め設定された所定曲率以上か否かを判定し、所定曲率未満の場合(ほぼ直線もしくは非常に緩やかなカーブから構成される道路)はC値設定部346からオフセットゲインとしてC=1を出力させ、所定曲率以上の場合(カーブ路)はカーブ時である旨の信号を最終リミッタ347に出力する曲率判定部341を有する。操舵トルク推定部342では、舵角と反力モータトルクに基づいてドライバのカーブ方向に対する操舵トルクを推定する。推定された操舵トルクは、B値設定部343及びラッチフラグ判定部345に出力される。
[About limiter processing of lateral force offset part]
Next, details of the limiter processing unit 34e in the lateral force offset unit 34 will be described. FIG. 21 is a block diagram illustrating a control configuration in the limiter processing unit in the lateral force offset unit according to the first embodiment. The limiter processing unit 34e determines whether or not the curvature is equal to or greater than a predetermined curvature set in advance. If the curvature is less than the predetermined curvature (a road composed of a substantially straight line or a very gentle curve), the limiter processing unit 34e is offset from the C value setting unit 346. C = 1 is output as a gain, and when it exceeds a predetermined curvature (curved road), it has a curvature determination unit 341 that outputs a signal to the final limiter 347 that it is a curve time. The steering torque estimation unit 342 estimates the steering torque with respect to the driver's curve direction based on the steering angle and the reaction force motor torque. The estimated steering torque is output to the B value setting unit 343 and the latch flag determination unit 345.
 A値設定部342では、操舵角センサ9により検出された舵角が、カメラ17が認識しているカーブ方向(曲率の方向)と反対方向に所定値以上操舵されているか否かを判断し、所定値未満の場合はA値としてA1を設定し、所定値以上の場合はA値としてA2を設定する。ここで、A2>A1であり、所定値以上の舵角が生じている場合には、横力オフセット量に対して、より積極的にドライバの操舵トルクを反映した制限をかけるものである。 The A value setting unit 342 determines whether or not the steering angle detected by the steering angle sensor 9 is steered by a predetermined value or more in a direction opposite to the curve direction (curvature direction) recognized by the camera 17, If it is less than the predetermined value, A1 is set as the A value, and if it is greater than the predetermined value, A2 is set as the A value. Here, when A2> A1 and a steering angle greater than or equal to a predetermined value occurs, the lateral force offset amount is more positively limited to reflect the driver's steering torque.
 B値設定部343では、カメラ17が認識しているカーブ方向とは反対方向の操舵トルクの大きさに基づいて設定される操舵トルク感応ゲインであり、A値に乗算することでドライバの操舵意図に基づく横力オフセット量を設定する。図23は実施例1のB値設定マップである。反対側の操舵トルクが0のときはB値=1であり、A値がそのまま使用される。そして、反対側の操舵トルクが大きくなるほどB値は1よりも小さな値に設定され、これによりA×BはA値よりも小さな値として補正される。 The B value setting unit 343 is a steering torque sensitivity gain that is set based on the magnitude of the steering torque in the direction opposite to the curve direction recognized by the camera 17, and by multiplying the A value, the driver's steering intention Sets the lateral force offset amount based on. FIG. 23 is a B value setting map according to the first embodiment. When the steering torque on the opposite side is 0, the B value = 1 and the A value is used as it is. As the steering torque on the opposite side increases, the B value is set to a value smaller than 1, thereby correcting A × B as a value smaller than the A value.
 C値設定部344では、A値設定部342で設定されたA値とB値設定部343で設定されたB値とを用いてオフセットゲインであるC値を以下の式より算出される。
C=(1-A)+A×B
ここで、仮にA=0.75とすると、A×Bの値は0.75~0の範囲で変化する。よって、オフセットゲインCは1~0.25の範囲で変化する。これの意味するところは、まず、反対方向の操舵トルクに感応して変更されるべきオフセット量の基本的な割合としてA値が設定されており、この場合、オフセット量の75%は反対方向の操舵トルクに感応する。言い換えると、反対方向の操舵トルクの大きさに係わらずオフセット量の25%は確保する。また、B値は反対方向の操舵トルクが0の場合は1であるため、操舵トルクが生じていない場合は、通常通りC=1の制御が行われる。そして、反対方向の操舵トルクが大きくなると、B値が1よりも小さな値となり、A×Bは小さくなるため、C値は1から徐々に0.25に向けて減少する。
The C value setting unit 344 calculates the C value, which is an offset gain, from the following equation using the A value set by the A value setting unit 342 and the B value set by the B value setting unit 343.
C = (1-A) + A × B
Here, assuming that A = 0.75, the value of A × B changes in the range of 0.75 to 0. Therefore, the offset gain C changes in the range of 1 to 0.25. This means that the A value is set as the basic ratio of the offset amount that should be changed in response to the steering torque in the opposite direction. In this case, 75% of the offset amount is in the opposite direction. Sensitive to steering torque. In other words, 25% of the offset amount is secured regardless of the magnitude of the steering torque in the opposite direction. Further, since the B value is 1 when the steering torque in the opposite direction is 0, the control of C = 1 is performed as usual when the steering torque is not generated. When the steering torque in the opposite direction increases, the B value becomes smaller than 1 and A × B decreases, so the C value gradually decreases from 1 toward 0.25.
 ラッチフラグ判定部345では、曲率と操舵トルク推定部341により推定された操舵トルクに基づいてカメラ17が認識しているカーブ方向と操舵トルクの方向とが一致し、所定値以上の操舵トルクが付与されているか否かを判断し、一致、かつ、所定値以上であればラッチフラグを1にセットし、最終リミッタ347にフラグ情報を出力する。 In the latch flag determination unit 345, the curve direction recognized by the camera 17 based on the curvature and the steering torque estimated by the steering torque estimation unit 341 coincides with the direction of the steering torque, and a steering torque greater than a predetermined value is applied. If it matches and is equal to or greater than a predetermined value, the latch flag is set to 1, and flag information is output to the final limiter 347.
 最終リミッタ347では、最終的なC値を決定し、前回もしくは今回の横力オフセット量に決定されたC値を乗算して最終的な横力オフセット量を出力する。以下、最終リミッタ347で行われる具体的な処理について説明する。 The final limiter 347 determines the final C value, multiplies the previous or current lateral force offset amount by the determined C value, and outputs the final lateral force offset amount. Hereinafter, specific processing performed in the final limiter 347 will be described.
 まず、曲率判定部340の判定結果に基づいて曲率が所定値未満で直線等であると判定された場合は、C値設定部346で設定されたC=1が選択される。そして、通常通り今回の制御周期における横力オフセット量に対してC値が乗算され、最終的な制御量として今回の制御周期における横力オフセット量が出力される。 First, when it is determined that the curvature is less than a predetermined value and is a straight line or the like based on the determination result of the curvature determination unit 340, C = 1 set by the C value setting unit 346 is selected. Then, the lateral force offset amount in the current control cycle is multiplied by the C value as usual, and the lateral force offset amount in the current control cycle is output as the final control amount.
 次に、曲率判定部340の判定結果が所定値以上でカーブ等であると判定された場合は、ラッチフラグ判定部345における判定結果に基づいてラッチフラグが1か否かを判断する。そして、ラッチフラグが1、つまり、カメラ17が認識しているカーブ方向とドライバの操舵トルクの方向とが一致しており、現時点でもカーブ方向と操舵トルク方向とが一致している場合には、やはりC=1が設定されて今回の制御周期における横力オフセット量が出力される。 Next, when it is determined that the determination result of the curvature determination unit 340 is a predetermined value or more and a curve or the like, it is determined whether or not the latch flag is 1 based on the determination result of the latch flag determination unit 345. If the latch flag is 1, that is, the curve direction recognized by the camera 17 matches the steering torque direction of the driver, and the curve direction and the steering torque direction still match at the present time, C = 1 is set and the lateral force offset amount in the current control cycle is output.
 一方、ラッチフラグが1であり、かつ、現時点ではカメラ17が認識しているカーブ方向とドライバの操舵トルクの方向とが不一致の場合には、カーブ方向と反対側の操舵トルクが検出されていることから、まず、ラッチフラグを0にリセットすると共に、横力オフセット量の前回値y1を記憶する。そして、A値設定部342により設定されたA値及びB値設定部343により設定されたB値を用いてC値を算出し、y1にC値を乗算して今回の横力オフセット量を出力する。図22は実施例1の反対側に操舵トルクが生じた場合における横力オフセット量の前回値と今回値との関係を表す概略図である。図22に示すように、C値は1未満の値にセットされるため、前回値を超えない範囲であって、かつ、反対側への操舵トルクの大きさに応じた横力オフセット量を設定することができる。 On the other hand, if the latch flag is 1 and the curve direction currently recognized by the camera 17 does not match the steering torque direction of the driver, the steering torque on the side opposite to the curve direction is detected. First, the latch flag is reset to 0, and the previous value y1 of the lateral force offset amount is stored. The C value is calculated using the A value set by the A value setting unit 342 and the B value set by the B value setting unit 343, and the current lateral force offset amount is output by multiplying the C value by y1. To do. FIG. 22 is a schematic diagram illustrating the relationship between the previous value and the current value of the lateral force offset amount when the steering torque is generated on the opposite side of the first embodiment. As shown in FIG. 22, since the C value is set to a value less than 1, the lateral force offset amount is set in a range not exceeding the previous value and in accordance with the magnitude of the steering torque to the opposite side. can do.
 次に、作用について説明する。図24は実施例1の操舵制御装置において、比較的大きな曲率を有するカーブが連続する際の状態を表す概略図である。また、図25は実施例1の操舵制御装置において図24に示す状態を経過した場合におけるタイムチャートである。実施例1のように、カメラ17の撮像画像から得られた白線情報を用いて操舵を補助するシステムにあっては、比較的曲率の大きなカーブが連続する場面もしくは高速走行状態の場合、路面変化に対して白線認識が追い付かず、車両挙動との乖離が生じる、すなわち白線認識が遅れる場面がある。この場合、ドライバは目視により道路形状を認識して操舵を行っており、このドライバ認識はカメラ17による認識よりも速いため、ドライバ認識に基づく操作に対してカメラ認識による補助が困難となる場合がある。 Next, the operation will be described. FIG. 24 is a schematic diagram showing a state when curves having a relatively large curvature continue in the steering control device of the first embodiment. FIG. 25 is a time chart when the state shown in FIG. 24 has elapsed in the steering control device of the first embodiment. In the system that assists steering using the white line information obtained from the image captured by the camera 17 as in the first embodiment, the road surface changes in a scene where a curve having a relatively large curvature continues or in a high-speed traveling state. On the other hand, there is a scene where white line recognition does not catch up and there is a deviation from vehicle behavior, that is, white line recognition is delayed. In this case, the driver visually recognizes the road shape and performs steering, and the driver recognition is faster than the recognition by the camera 17, so it may be difficult to assist the operation based on the driver recognition by the camera recognition. is there.
 図23に示すように、例えば、最初のカーブではある程度ドライバ認識とカメラ認識とが一致しており、適切な操舵補助ができたとしても、次のカーブに対しては、カメラ認識が遅れると、ドライバの認識するカーブ方向とカメラ17が認識するカーブ方向とは反対となる場面が想定される。このとき、既にドライバが次のカーブ状況を見越して操舵を開始すると、カメラ17側で認識しているカーブの曲率は反対側であるから横力オフセット量が設定されたままであると、ドライバが反対側に操舵する際には、極めて大きな反力が作用してしまい、操舵を妨げるおそれがあり、ドライバにとっては違和感となる。 As shown in FIG. 23, for example, in the first curve, the driver recognition and the camera recognition are matched to some extent, and even if the appropriate steering assist is made, if the camera recognition is delayed for the next curve, It is assumed that the curve direction recognized by the driver is opposite to the curve direction recognized by the camera 17. At this time, if the driver has already started steering in anticipation of the next curve situation, the curvature of the curve recognized on the camera 17 side is the opposite side, so if the lateral force offset amount remains set, the driver will When steering to the side, an extremely large reaction force is applied, which may hinder steering, which makes the driver feel uncomfortable.
 そこで、実施例1では、カーブ方向と反対側の操舵トルクを検出し、カーブ方向と反対側の操舵トルクが所定値以上発生した場合には、反対側の操舵トルクに応じて横力オフセット量を低減することで上記違和感を解消することとした。 Therefore, in the first embodiment, when the steering torque on the opposite side to the curve direction is detected and the steering torque on the opposite side to the curve direction is generated at a predetermined value or more, the lateral force offset amount is set according to the opposite steering torque. By reducing it, the above-mentioned uncomfortable feeling was resolved.
 図24の(1)のゾーンに示すように、カメラ17が認識しているカーブ方向と操舵トルク方向とが一致している場合には、特に横力オフセット量が制限されず、ラッチフラグが1にセットされている。そして、(2)のゾーンに示すように、カメラ17側では、まだカーブ方向が反対となったとは認識しておらず、右側カーブであると認識した状態で横力オフセット量を算出している一方で、ドライバは次のカーブの状態を意識して反対側にステアリングホイール6を操舵する。すると、ラッチフラグは0にリセットされる。ここで、右側に横力オフセット量が設定されていることから、左側に操舵すると、操舵反力としては非常に大きくなってしまい、ドライバは反対側へ操舵することが困難となる。この現象を回避するために、反対側の操舵トルクの大きさに応じてC値が設定され、横力オフセット量が低減される。これにより反対側の操舵トルクが抑制されるため、ドライバは反対側への操舵が可能となる。 As shown in the zone (1) in FIG. 24, when the curve direction recognized by the camera 17 matches the steering torque direction, the lateral force offset amount is not particularly limited, and the latch flag is set to 1. It is set. Then, as shown in the zone (2), the camera 17 side does not recognize that the curve direction has been reversed yet, and calculates the lateral force offset amount in a state where it is recognized as the right curve. On the other hand, the driver steers the steering wheel 6 to the opposite side while being aware of the state of the next curve. Then, the latch flag is reset to 0. Here, since the lateral force offset amount is set on the right side, when steering to the left side, the steering reaction force becomes very large, making it difficult for the driver to steer to the opposite side. In order to avoid this phenomenon, the C value is set according to the magnitude of the opposite side steering torque, and the lateral force offset amount is reduced. As a result, the steering torque on the opposite side is suppressed, so that the driver can steer to the opposite side.
 このとき、ドライバの操舵角が所定値以上となると、反対側への操舵の意図が確実であると判断できるため、A値としてA1よりも大きなA2に切り替えられ、より小さなC値が演算される。これにより、横力オフセット量は更に小さな値となり、更に違和感が低減できる。
 次に、(3)のゾーンに示すように、カメラ17が認識しているカーブ方向と操舵トルクの方向とが一致した場合には、ラッチフラグが1にセットされ、C値としてC=1が設定されて通常の制御が行われる。
At this time, if the steering angle of the driver exceeds a predetermined value, it can be determined that the intention of steering to the opposite side is certain, so the A value is switched to A2, which is larger than A1, and a smaller C value is calculated. . As a result, the lateral force offset amount becomes a smaller value, and the uncomfortable feeling can be further reduced.
Next, as shown in zone (3), when the curve direction recognized by the camera 17 matches the steering torque direction, the latch flag is set to 1, and C = 1 is set as the C value. Then, normal control is performed.
 以上説明したように、実施例1にあっては以下に列挙する効果を奏する。
  (1)左右前輪5FL,5FR(転舵輪)を転舵する転舵部2と機械的に切り離されドライバの操舵入力を受ける操舵部1と、セルフアライニングトルクと操舵反力を座標軸とする座標上に、セルフアライニングトルクが大きいほど大きな操舵反力となる操舵反力特性を設定し、当該操舵反力特性に基づいて操舵部1に操舵反力を付与する操舵反力制御部20と、白線の曲率を検出する曲率演算部34aと、検出された曲率が大きいほど大きなオフセット量を算出し、座標上で操舵反力特性をセルフアライニングトルクと同一符号方向へオフセット量だけオフセットする横力オフセット部34(オフセット手段)と、カメラ17により検出された曲率のカーブ方向と反対側の操舵トルクを検出する操舵トルク推定部342(反対側操舵トルク検出手段)と、カメラ17により検出されたカーブ方向と反対側の操舵トルクが大きいほど横力オフセット量を低減するリミッタ処理部34e(オフセット量低減手段)を備えた。
 すなわち、カメラ17の認識遅れに伴って遅れて横力オフセット量が算出された場合であっても、ドライバが認識しているカーブ方向に向かって操舵することで、カメラ17が認識している曲率のカーブ方向と反対側の操舵トルクが発生している状態では、横力オフセット量を低減することで、操舵反力を小さくすることができ、ドライバが反対側に操舵する際に大きな反力が発生することによる違和感を回避できる。
As described above, Example 1 has the following effects.
(1) Steering unit 2 that steers left and right front wheels 5FL and 5FR (steering wheels) and steering unit 1 that is mechanically separated and receives steering input from the driver, and coordinates that use self-aligning torque and steering reaction force as coordinate axes Above, a steering reaction force characteristic that sets a steering reaction force that becomes a larger steering reaction force as the self-aligning torque is larger, and applies a steering reaction force to the steering unit 1 based on the steering reaction force characteristic, A curvature calculation unit 34a that detects the curvature of the white line, and a lateral force that calculates a larger offset amount as the detected curvature is larger and offsets the steering reaction force characteristic on the coordinates in the same sign direction as the self-aligning torque by the offset amount An offset unit 34 (offset unit), a steering torque estimation unit 342 (opposite side steering torque detection unit) that detects a steering torque on the side opposite to the curve direction of the curvature detected by the camera 17, and a camera 17 detects the steering torque. Was equipped with the curve direction of the limiter processing unit 34e to reduce the higher lateral force offset amount is large steering torque on the opposite side (the offset amount reducing means).
That is, even when the lateral force offset amount is calculated with a delay in recognition of the camera 17, the curvature recognized by the camera 17 is steered toward the curve direction recognized by the driver. In the state where the steering torque on the side opposite to the curve direction is generated, the lateral reaction offset amount can be reduced to reduce the steering reaction force, and a large reaction force is generated when the driver steers to the opposite side. A sense of incongruity caused by the occurrence can be avoided.
 (2) 操舵角がカメラ17により検出された曲率のカーブ方向と反対側に所定操舵角以上操舵されているか否かを判断するA値設定部342(反対側操舵角判断手段)を設け、最終リミッタ347は、操舵角が所定操舵角以上操舵されている場合は、所定操舵角未満の場合に設定されるA1より大きなA2を設定することで横力オフセット量を大きく低減させることとした。
 よって、ドライバの操舵意図がはっきりした段階では、更に横力オフセット量を低減することでドライバの違和感を低減できる。
(2) An A value setting unit 342 (opposite steering angle determination means) is provided for determining whether or not the steering angle is steered beyond a predetermined steering angle on the side opposite to the curve direction of the curvature detected by the camera 17. The limiter 347 greatly reduces the lateral force offset amount by setting A2 larger than A1 set when the steering angle is steered beyond the predetermined steering angle.
Therefore, when the driver's steering intention is clear, the driver's uncomfortable feeling can be reduced by further reducing the lateral force offset amount.
 (3)操舵反力特性は、セルフアライニングトルクが小さいときは、大きいときよりもセルフアライニングトルクの変化量に対する操舵反力の変化量が大きい。
 これにより、曲率が大きいほど保舵トルクの変化に対する操舵角の変動が小さくなるため、操舵トルクに対する車両の感度が低く抑えられ、旋回中のドライバによる進路修正の容易化を実現できる。また、操舵角を維持するための保舵トルクを小さくできるため、旋回時におけるドライバの操舵負担を軽減できる。
(3) Regarding the steering reaction force characteristic, when the self-aligning torque is small, the change amount of the steering reaction force with respect to the change amount of the self-aligning torque is larger than when the self-aligning torque is large.
As a result, the greater the curvature, the smaller the variation in the steering angle with respect to the change in the steering torque, so that the sensitivity of the vehicle to the steering torque can be kept low, and the course correction by the driver during the turn can be facilitated. Moreover, since the steering torque for maintaining the steering angle can be reduced, the steering burden on the driver during turning can be reduced.
 (4)セルフアライニングトルクと操舵反力を座標軸とする座標上に、セルフアライニングトルクが大きいほど大きな操舵反力となる操舵反力特性を設定し、当該操舵反力特性に基づいて転舵部2と機械的に切り離された操舵部1に操舵反力を付与する際、白線の曲率が大きいほど大きな横力オフセット量を算出し、座標上で操舵反力特性をセルフアライニングトルクと同一符号方向へオフセット量だけオフセットするにあたり、カメラ17により検出された曲率のカーブ方向と反対側の操舵トルクが大きいほど横力オフセット量を低減することとした。
 すなわち、カメラ17の認識遅れに伴って遅れて横力オフセット量が算出された場合であっても、ドライバが認識しているカーブ方向に向かって操舵することで、カメラ17が認識している曲率のカーブ方向と反対側の操舵トルクが発生している状態では、横力オフセット量を低減することで、操舵反力を小さくすることができ、ドライバが反対側に操舵する際に大きな反力が発生することによる違和感を回避できる。
(4) On the coordinates with the self-aligning torque and steering reaction force as the coordinate axes, set the steering reaction force characteristic that becomes a larger steering reaction force as the self-aligning torque becomes larger, and steer based on the steering reaction force characteristic When steering reaction force is applied to the steering unit 1 mechanically separated from the part 2, the larger lateral force offset is calculated as the curvature of the white line is larger, and the steering reaction force characteristic is the same as the self-aligning torque on the coordinates When the offset amount is offset in the sign direction, the lateral force offset amount is reduced as the steering torque on the side opposite to the curve direction of the curvature detected by the camera 17 increases.
That is, even when the lateral force offset amount is calculated with a delay in recognition of the camera 17, the curvature recognized by the camera 17 is steered toward the curve direction recognized by the driver. In the state where the steering torque on the side opposite to the curve direction is generated, the lateral reaction offset amount can be reduced to reduce the steering reaction force, and a large reaction force is generated when the driver steers to the opposite side. A sense of incongruity caused by the occurrence can be avoided.
 (5) 白線の曲率を検出するカメラ17及び曲率演算部34a(センサ)と、カメラ17により検出された曲率のカーブ方向と反対側の操舵トルクを検出する操舵トルク推定部341(センサ)と、セルフアライニングトルクと操舵反力を座標軸とする座標上に、セルフアライニングトルクが大きいほど大きな操舵反力となる操舵反力特性を設定し、当該操舵反力特性に基づいて転舵部2と機械的に切り離された操舵部1に操舵反力を付与する際、白線の曲率が大きいほど大きなオフセット量を算出し、座標上で操舵反力特性をセルフアライニングトルクと同一符号方向へオフセット量だけオフセットするにあたり、カメラ17により検出された曲率のカーブ方向と反対側の操舵トルクが大きいほど横力オフセット量を低減するSBWコントローラ4(コントローラ)と、を備えた。
 すなわち、カメラ17の認識遅れに伴って遅れて横力オフセット量が算出された場合であっても、ドライバが認識しているカーブ方向に向かって操舵することで、カメラ17が認識している曲率のカーブ方向と反対側の操舵トルクが発生している状態では、横力オフセット量を低減することで、操舵反力を小さくすることができ、ドライバが反対側に操舵する際に大きな反力が発生することによる違和感を回避できる。
(5) A camera 17 and a curvature calculation unit 34a (sensor) that detect the curvature of the white line, a steering torque estimation unit 341 (sensor) that detects a steering torque opposite to the curve direction of the curvature detected by the camera 17, On the coordinates with the self-aligning torque and steering reaction force as coordinate axes, a steering reaction force characteristic is set, which becomes a larger steering reaction force as the self-aligning torque is larger, and based on the steering reaction force characteristic, When applying the steering reaction force to the mechanically separated steering unit 1, the larger the white line curvature is, the larger the offset amount is calculated, and the steering reaction force characteristic on the coordinates is offset in the same sign direction as the self-aligning torque. SBW controller 4 (controller) that reduces the lateral force offset amount as the steering torque on the side opposite to the curve direction of the curvature detected by the camera 17 increases. Equipped with.
That is, even when the lateral force offset amount is calculated with a delay in recognition of the camera 17, the curvature recognized by the camera 17 is steered toward the curve direction recognized by the driver. In the state where the steering torque on the side opposite to the curve direction is generated, the lateral reaction offset amount can be reduced to reduce the steering reaction force, and a large reaction force is generated when the driver steers to the opposite side. A sense of incongruity caused by the occurrence can be avoided.

Claims (5)

  1.  転舵輪を転舵する転舵部と機械的に切り離されドライバの操舵入力を受ける操舵部と、
     セルフアライニングトルクと操舵反力を座標軸とする座標上に、セルフアライニングトルクが大きいほど大きな操舵反力となる操舵反力特性を設定し、当該操舵反力特性に基づいて前記操舵部に操舵反力を付与する操舵反力制御手段と、
     白線の曲率を検出する曲率検出手段と、
     前記検出された曲率が大きいほどセルフアライニングトルクと大きなオフセット量を算出し、前記座標上で前記操舵反力特性を前記セルフアライニングトルクと同一符号方向へ前記オフセット量だけオフセットするオフセット手段と、
     前記検出された曲率のカーブ方向と反対側の操舵トルクを検出する反対側操舵トルク検出手段と、
     前記検出された曲率のカーブ方向と反対側の操舵トルクが大きいほど前記オフセット量を低減するオフセット量低減手段と、
     を備えたことを特徴とする操舵制御装置。
    A steering part that is mechanically separated from a steered part that steers steered wheels and receives a steering input of a driver;
    On the coordinates with the self-aligning torque and steering reaction force as coordinate axes, a steering reaction force characteristic is set, which becomes a larger steering reaction force as the self-aligning torque is larger, and the steering unit is steered based on the steering reaction force characteristic. Steering reaction force control means for applying reaction force;
    Curvature detection means for detecting the curvature of the white line;
    An offset means for calculating a self-aligning torque and a large offset amount as the detected curvature is larger, and offsetting the steering reaction force characteristic by the offset amount in the same sign direction as the self-aligning torque on the coordinates;
    An opposite side steering torque detecting means for detecting a steering torque on the opposite side to the curve direction of the detected curvature;
    Offset amount reducing means for reducing the offset amount as the steering torque on the opposite side to the curve direction of the detected curvature is larger;
    A steering control device comprising:
  2.  請求項1に記載の操舵制御装置において、
     操舵角が前記検出された曲率のカーブ方向と反対側に所定操舵角以上操舵されているか否かを判断する反対側操舵角判断手段を設け、
     前記オフセット量低減手段は、操舵角が前記所定操舵角以上操舵されている場合は前記所定操舵角未満の場合に比べて前記オフセット量を大きく低減させることを特徴とする操舵制御装置。
    The steering control device according to claim 1, wherein
    An opposite-side steering angle determination means for determining whether the steering angle is steered by a predetermined steering angle or more on the opposite side to the detected curve direction of the curvature,
    The offset amount reducing means reduces the offset amount largely when the steering angle is steered more than the predetermined steering angle as compared with the case where the steering angle is less than the predetermined steering angle.
  3.  請求項1または2に記載の操舵制御装置において、
     前記操舵反力特性は、セルフアライニングトルクが小さいときは大きいときよりもセルフアライニングトルクの変化量に対する操舵反力の変化量が大きいことを特徴とする操舵制御装置。
    The steering control device according to claim 1 or 2,
    The steering control device according to claim 1, wherein the steering reaction force characteristic has a larger change amount of the steering reaction force with respect to a change amount of the self-aligning torque when the self-aligning torque is small than when the self-aligning torque is large.
  4.  セルフアライニングトルクと操舵反力を座標軸とする座標上に、セルフアライニングトルクが大きいほど大きな操舵反力となる操舵反力特性を設定し、当該操舵反力特性に基づいて転舵部と機械的に切り離された操舵部に操舵反力を付与する際、白線の曲率が大きいほど大きなオフセット量を算出し、前記座標上で前記操舵反力特性を前記セルフアライニングトルクと同一符号方向へ前記オフセット量だけオフセットするにあたり、検出された曲率のカーブ方向と反対側の操舵トルクが大きいほど前記オフセット量を低減することを特徴とする操舵制御装置。 On the coordinates with the self-aligning torque and the steering reaction force as coordinate axes, a steering reaction force characteristic is set that becomes a larger steering reaction force as the self-aligning torque becomes larger. Based on the steering reaction force characteristic, the steering unit and the machine When the steering reaction force is applied to the steered steering part, a larger offset amount is calculated as the curvature of the white line is larger, and the steering reaction force characteristic in the same sign direction as the self-aligning torque is calculated on the coordinates. A steering control device characterized by reducing the offset amount as the steering torque on the side opposite to the detected curve direction of the curvature increases in offsetting the offset amount.
  5.  白線の曲率を検出するセンサと、
     検出された曲率のカーブ方向と反対側の操舵トルクを検出するセンサと、
     セルフアライニングトルクと操舵反力を座標軸とする座標上に、セルフアライニングトルクが大きいほど大きな操舵反力となる操舵反力特性を設定し、当該操舵反力特性に基づいて転舵部と機械的に切り離された操舵部に操舵反力を付与する際、白線の曲率が大きいほど大きなオフセット量を算出し、前記座標上で前記操舵反力特性を前記セルフアライニングトルクと同一符号方向へ前記オフセット量だけオフセットするにあたり、検出された曲率のカーブ方向と反対側の操舵トルクが大きいほど前記オフセット量を低減するコントローラと、
     を備えたことを特徴とする操舵制御装置。
    A sensor for detecting the curvature of the white line;
    A sensor for detecting a steering torque on the opposite side to the curve direction of the detected curvature;
    On the coordinates with the self-aligning torque and the steering reaction force as coordinate axes, a steering reaction force characteristic is set that becomes a larger steering reaction force as the self-aligning torque becomes larger. Based on the steering reaction force characteristic, the steering unit and the machine When the steering reaction force is applied to the steered steering part, a larger offset amount is calculated as the curvature of the white line is larger, and the steering reaction force characteristic in the same sign direction as the self-aligning torque is calculated on the coordinates. A controller that reduces the offset amount as the steering torque on the side opposite to the curve direction of the detected curvature increases when offsetting by the offset amount;
    A steering control device comprising:
PCT/JP2013/076679 2012-10-04 2013-10-01 Steering control device WO2014054627A1 (en)

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