JP4648229B2 - Vehicle operation support device - Google Patents

Description

  The present invention relates to a vehicle operation support device that supports a collision avoidance operation performed by a driver to avoid a collision with an obstacle when the vehicle is traveling.

  In a power steering control device that controls an assist force for steering of a vehicle according to a running state, compared to an assist force given for steering in a target steering angle direction, the steering force in a direction opposite to the target steering angle direction Patent Document 1 below discloses that the assist force given in this way is set to be small so that steering in the direction opposite to the target steering angle direction is prevented so that the vehicle does not deviate from the road.

Also, when the vehicle is approaching the limit of understeer turning and there is a risk that the behavior of the vehicle will be disturbed if the steering wheel is further increased, the increase of the assist torque is prohibited or the assist torque is decreased. Japanese Patent Application Laid-Open Publication No. 2004-259542 discloses that the vehicle is approaching the turning limit and suppresses the increase in steering wheel to prevent the vehicle behavior from being disturbed.
JP 2000-72021 A JP 2004-352031 A

  By the way, in a vehicle operation support device that assists the steering operation of the driver by operating the steering actuator, the steering actuator is operated when the driver suddenly operates the steering wheel and the collision is avoided because the vehicle is likely to contact an obstacle. If excessive assist is performed, the steering wheel may become too light, causing disturbance in vehicle behavior, or making the driver feel uncomfortable.

  The present invention has been made in view of the above circumstances, and in a vehicle operation support device that assists a driver's steering operation, when the vehicle is about to contact an obstacle, the steering wheel becomes too light with excessive assistance. The purpose is to prevent.

  In order to achieve the above object, according to the first aspect of the present invention, in a vehicle operation support device that supports a collision avoidance operation performed by a driver to avoid a collision with an obstacle when the vehicle is running, Reference yaw rate calculation means for calculating a reference yaw rate, collision avoidance operation determination means for determining a collision avoidance operation by a driver, obstacle detection means for detecting an obstacle with which the host vehicle may collide, and collision avoidance operation determination When the means determines the collision avoidance operation by the driver, the avoidance exercise amount calculation means for calculating the avoidance exercise amount necessary for avoiding the obstacle detected by the obstacle detection means, and the reference yaw rate calculated by the reference yaw rate calculation means The normative yaw rate correcting means for correcting with the avoiding momentum calculated by the avoiding momentum calculating means, and the And a target assist current calculating means for calculating a target assist current to be supplied to the steering actuator, and a collision avoidance operation determining means in accordance with a steering torque input to the steering wheel by the driver when the collision avoidance operation is determined by the driver. There is proposed a vehicle operation support device comprising target assist current regulating means for regulating an upper limit value of the target assist current calculated by the target assist current calculating means.

  According to the second aspect of the present invention, in the vehicle operation support device that supports the collision avoidance operation performed by the driver to avoid the collision with the obstacle when the vehicle is traveling, the collision that determines the collision avoidance operation by the driver. The avoidance operation determination means, the obstacle detection means for detecting an obstacle with which the host vehicle may collide, and the obstacle detection means detected when the collision avoidance operation determination means determined the collision avoidance operation by the driver. Avoidance exercise amount calculating means for calculating an avoidance exercise amount necessary for avoiding the obstacle, target assist current calculation means for calculating a target assist current to be supplied to the steering actuator based on the avoidance exercise amount calculated by the avoidance exercise amount calculation means, When the collision avoidance operation determination means determines the collision avoidance operation by the driver, the driver enters the steering wheel. Vehicle operation supporting device being characterized in that a target assist electric current regulating means for regulating the upper limit of the target assist current calculated by the target assist current calculation means in accordance with the steering torque is proposed.

  According to the third aspect of the present invention, in addition to the configuration of the first or second aspect, the target assist current regulating means is configured such that the direction of the steering torque input by the driver to the steering wheel is the direction of the target assist current. A vehicle operation support device is proposed in which the upper limit value of the target assist current is set lower in the same direction as in the case of the reverse direction.

  According to the configuration of claim 1, when the driver performs the collision avoidance operation with the obstacle, the avoidance momentum necessary for the vehicle to avoid the obstacle is calculated, and the reference yaw rate corrected by the avoidance momentum and the actual yaw rate are calculated. A target assist current to be supplied to the steering actuator is calculated based on the deviation from the yaw rate, and this target assist current is supplied to the steering actuator to assist the driver's collision avoidance operation. When the collision avoidance operation by the driver is determined, the upper limit value of the target assist current is regulated according to the steering torque input by the driver to the steering wheel, so that the steering wheel is prevented from becoming too light due to excessive assist. In addition to eliminating the driver's uncomfortable feeling due to the deterioration of the steering feeling, it is possible to prevent disturbance of the vehicle behavior due to excessive assist.

  According to the configuration of claim 2, when the driver performs the collision avoidance operation with the obstacle, the avoidance momentum necessary for the own vehicle to avoid the obstacle is calculated and supplied to the steering actuator based on the avoidance momentum. A target assist current is calculated, and this target assist current is supplied to the steering actuator to assist the driver's collision avoidance operation. When the collision avoidance operation by the driver is determined, the upper limit value of the target assist current is regulated according to the steering torque input by the driver to the steering wheel, so that the steering wheel is prevented from becoming too light due to excessive assist. In addition to eliminating the driver's uncomfortable feeling due to the deterioration of the steering feeling, it is possible to prevent disturbance of the vehicle behavior due to excessive assist.

  According to the configuration of the third aspect, when the direction of the steering torque input by the driver to the steering wheel is the same direction as the direction of the target assist current, the upper limit value of the target assist current becomes low, so the target assist current is excessive. Therefore, the steering wheel can be prevented from becoming too light, and the steering wheel can be prevented from being overcut. In addition, when the direction of the steering torque input to the steering wheel by the driver is opposite to the direction of the target assist current, the upper limit value of the target assist current becomes high. It is possible to prevent the incision from being prevented and prevent the steering wheel from being overcut.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below based on examples of the present invention shown in the accompanying drawings.

  1 to 5 show a first embodiment of the present invention. FIG. 1 is a diagram showing the overall configuration of an automobile equipped with an operation support device, FIG. 2 is a diagram showing the configuration of a steering device, and FIG. FIG. 4 is an explanatory diagram of the target lateral movement distance, and FIG. 5 is a graph showing the relationship between the steering torque and the maximum value of the correction current.

  As shown in FIGS. 1 and 2, the four-wheeled vehicle equipped with the operation support device of the present embodiment has left and right front wheels WFL, WFR as drive wheels to which the driving force of the engine E is transmitted via a transmission T. The left and right rear wheels WRL and WRR are driven wheels that rotate as the vehicle travels.

  The rotation of the steering wheel 11 is transmitted to the rack 15 via the steering shaft 12, the connecting shaft 13 and the pinion 14, and the reciprocation of the rack 15 is transmitted to the left and right front wheels WFL, WFR via the left and right tie rods 16, 16. The The power steering device 17 provided in the steering device includes a drive gear 19 provided on the output shaft of the steering actuator 18, a driven gear 20 that meshes with the drive gear 19, a screw shaft 21 that is integrated with the driven gear 20, And a nut 22 engaged with the screw shaft 21 and connected to the rack 15. Therefore, when the steering actuator 18 is driven, the driving force is transmitted to the left and right front wheels WFL, WFR via the drive gear 19, the driven gear 20, the screw shaft 21, the nut 22, the rack 15, and the left and right tie rods 16,16. be able to.

  The electronic control unit U emits electromagnetic waves such as millimeter waves toward the front of the vehicle body, and based on the reflected waves, the relative distance between the obstacle and the vehicle, the relative speed between the obstacle and the vehicle, A radar device Sa that detects the offset distance from the host vehicle and the lateral width of the obstacle, a wheel speed sensor Sb that detects the rotational speeds of the front wheels WFL, WFR and the rear wheels WRL, WRR, and a steering angle δ of the steering wheel 11 The steering angle sensor Sc to be detected, the steering torque sensor Sd to detect the steering torque T input to the steering wheel 11, and the yaw rate sensor Se to detect the actual yaw rate γ of the vehicle are connected.

  Note that a laser radar can be employed in place of the radar device Sa composed of a millimeter wave radar.

  The electronic control unit U controls the operation of the steering actuator 18 based on signals from the radar device Sa and signals from the wheel speed sensor Sb..., Steering angle sensor Sc, steering torque sensor Sd, and yaw rate sensor Se.

  As shown in FIG. 3, the electronic control unit U includes a reference yaw rate calculation means M1, a collision avoidance operation determination means M2, an obstacle detection means M3, an avoidance exercise amount calculation means M4, a reference yaw rate correction means M5, a target Assist steering angle calculating means M6, target assist current calculating means M7, target assist current regulating means M8, and target current calculating means M9 are provided.

  Next, the normal operation in which the driver does not perform the obstacle avoidance operation will be described.

  The reference yaw rate calculation means M1 calculates a reference yaw rate γt based on the steering angle δ detected by the steering angle sensor Sc and the vehicle speed V calculated from the output of the wheel speed sensor Sb. The target assist steering angle calculation means M6 calculates a target assist steering angle based on the deviation between the actual yaw rate γ detected by the yaw rate sensor Se and the standard yaw rate γt. When the actual yaw rate γ is larger than the reference yaw rate γt, the vehicle is in an oversteer state, and when the actual yaw rate γ is smaller than the reference yaw rate γt, the vehicle is in an understeer state. This corresponds to the steering angle added by the power steering device 17 to the steering angle δ at which the driver actually operates the steering wheel 11 in order to eliminate the steer state and the understeer state. The target assist current calculation means M7 converts the target assist steering angle calculated by the target assist steering angle calculation means M6 into a target assist current that is supplied to the steering actuator 18.

  The target current calculation means M9 calculates a target current to be supplied to the steering actuator 18 based on, for example, the steering torque T detected by the steering torque sensor Sd and the vehicle speed V calculated from the output of the wheel speed sensor Sb. . Then, the steering actuator 18 is driven based on the current value obtained by adding the target assist current converted by the target assist current calculating means M7 to the target current calculated by the target current calculating means M9. Thus, when the vehicle is in an oversteer tendency, the steering wheel 11 is lightened in the direction of turning back, and when the vehicle is in an understeer tendency, the ease of turning the steering wheel 11 is suppressed to assist the driver's steering operation. it can.

  Next, the operation at the time of avoidance in which the driver performs an obstacle avoidance operation will be described.

  The collision avoidance operation determination means M2 determines whether or not the driver has performed an operation for avoiding the obstacle O based on the steering angle δ of the steering wheel 11 detected by the steering angle sensor Sc. Specifically, the steering angular velocity dδ / dt obtained by time differentiation of the steering angle δ is equal to or higher than a predetermined value (for example, 0.85 rad / sec), or the steering angle δ output from the steering angle sensor Sc is a predetermined value (for example, 0.3 rad). At this time, it is determined that the driver has performed an operation for avoiding the obstacle.

  As shown in FIG. 4, in addition to the relative speed and relative distance between the obstacle O and the own vehicle, the radar device Sa has a lateral width w of the obstacle O and a deviation of the center of the obstacle O from the center line of the own vehicle. That is, the offset distance Do is detected.

The obstacle detection means M3 determines the obstacle O on the predicted course of the host vehicle based on the detection result by the radar device Sa. When the collision avoidance operation determination means M2 determines the avoidance operation by the driver, the avoidance exercise amount calculation means M4 determines whether the avoidance exercise amount calculation means M4 uses the width W of the obstacle O, the known width W of the host vehicle, and the predetermined margin α. The avoidance momentum (target lateral movement distance) Dt necessary for the vehicle to avoid the obstacle O is
Dt = (w / 2) + (W / 2) + α-Do
Calculated by

  It is most difficult to avoid a collision between the own vehicle and the obstacle O when the center of the obstacle O is on the center line of the own vehicle, that is, when the obstacle O is directly in front of the own vehicle. Even in this case, if the vehicle moves in the lateral direction by the target lateral movement distance Dt, it can pass through the obstacle O with a margin corresponding to the margin α.

  The normative yaw rate correcting means M5 corrects the normative yaw rate γt calculated by the normative yaw rate calculating means M1 by the avoiding exercise amount Dt calculated by the avoiding exercise amount calculating means M4. As a result, the standard yaw rate γt calculated from the steering angle δ and the vehicle speed V is corrected so as to increase as it becomes difficult for the vehicle to avoid the obstacle O. Thus, when the driver performs a steering operation for avoiding a collision with the obstacle O, the steering operation can be assisted by the power steering device 17 to effectively avoid the collision.

  The target assist current regulating means M8 is a correction current which is a current converted value of the target assist steering angle based on the steering torque T detected by the steering torque sensor Sd when the collision avoidance operation determining means M2 determines the avoidance operation by the driver. Regulate the maximum value of.

  As shown in FIG. 5, when the direction of the steering torque T input to the steering wheel 11 by the driver and the direction of the assist current calculated by the target assist current calculation means M7 are the same direction, the maximum value of the correction current is a low value. Regulated by On the other hand, when the direction of the steering torque T input by the driver to the steering wheel 11 is opposite to the direction of the assist current calculated by the target assist current calculation means M7, the maximum value of the correction current is restricted to a high value.

  That is, when the steering torque T is greater than T1 (> 0), the maximum value of the correction current is a constant value of Imax1, and when the steering torque T is less than T2 (<0), the maximum value of the correction current is Imax2 (> Imax1) is a constant value, and when the steering torque T is T2 or more and T1 or less, the maximum value of the correction current linearly decreases from Imax2 to Imax1.

  Thus, when the direction of the steering torque T input by the driver to the steering wheel 11 and the direction of the assist current calculated by the target assist current calculation means M7 are the same direction, the steering assist force generated by the power steering device 17 is excessive. It is possible to prevent the steering wheel 11 from becoming too light. On the other hand, when the direction of the steering torque T input by the driver to the steering wheel 11 and the direction of the assist current calculated by the target assist current calculation means M7 are opposite directions, a sufficient steering resistance force is generated in the power steering device 17. Thus, it is possible to avoid the problem that the steering wheel 11 is not returned due to insufficient steering resistance.

  As a result, the disturbance of the vehicle behavior due to the excessive assist of the power steering device 17 can be prevented, and the uncomfortable feeling of the driver due to the deterioration of the steering feeling can be solved. Further, since the steering wheel 11 becomes heavy, it is possible to notify the driver that the steering is not appropriate and prompt the driver to switch back, thereby avoiding obstacles and stabilizing vehicle behavior.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In the first embodiment described above, as shown in FIG. 3, when the collision avoidance operation determination means M2 determines an avoidance operation by the driver, the avoidance momentum calculation means M4 avoids the obstacle O detected by the obstacle detection means M3. The avoidance exercise amount Dt necessary for the calculation is calculated, and the reference yaw rate correction means M5 corrects the reference yaw rate γt calculated by the reference yaw rate calculation means M1 with the avoidance exercise amount Dt. The target assist steering angle calculation means M6 calculates a target assist steering angle based on the deviation between the actual yaw rate γ and the reference yaw rate γt, and the target assist current calculation means M7 supplies the target assist steering angle to the steering actuator 18. Convert to assist current.

  On the other hand, the second embodiment does not include the normative yaw rate calculating means M1, normative yaw rate correcting means M5 and target assist steering angle calculating means M6 of the first embodiment as shown in FIG. Based on the avoidance exercise amount Dt calculated by M4, the target assist current calculation means M7 directly calculates the target assist current. Thereafter, the target assist current regulating means M8 regulates the maximum value of the correction current, which is the current converted value of the target assist steering angle, based on the steering torque T when the avoidance operation by the driver is determined. This is the same as in the first embodiment.

  Thus, according to the second embodiment, the standard yaw rate calculation means M1, the standard yaw rate correction means M5, and the target assist steering angle calculation means M6 are abolished while achieving the same operational effects as the first embodiment described above. Therefore, the structure of the control system can be simplified.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the embodiment, the collision with the obstacle O is avoided at the front wheel steering angle generated by the power steering device 17, but it is generated by giving a difference between the braking force of the left wheel and the braking force of the right wheel. It is also possible to avoid collision with the obstacle O with the yaw moment.

The figure which shows the whole structure of the motor vehicle carrying the operation assistance apparatus which concerns on 1st Example. Diagram showing the configuration of the steering device Block diagram of the control system of the operation support device Illustration of target lateral movement distance Graph showing the relationship between steering torque and maximum correction current Block diagram of the control system of the operation support apparatus according to the second embodiment

Explanation of symbols

M1 reference yaw rate calculation means M2 collision avoidance operation determination means M3 obstacle detection means M4 avoidance movement amount calculation means M5 reference yaw rate correction means M7 target assist current calculation means M8 target assist current restriction means O obstacle T steering torque γ actual yaw rate γt reference yaw rate 11 Steering wheel 18 Steering actuator

Claims (3)

In a vehicle operation support device that supports a collision avoidance operation performed by a driver to avoid a collision with an obstacle (O) when the vehicle is running,
A reference yaw rate calculating means (M1) for calculating a reference yaw rate (γt) of the vehicle;
A collision avoidance operation determination means (M2) for determining a collision avoidance operation by the driver;
An obstacle detection means (M3) for detecting an obstacle (O) with which the host vehicle may collide,
When the collision avoidance operation determination means (M2) determines the collision avoidance operation by the driver, the avoidance exercise amount calculation calculates the avoidance exercise amount necessary to avoid the obstacle (O) detected by the obstacle detection means (M3). Means (M4);
A normative yaw rate correcting means (M5) for correcting the normative yaw rate (γt) calculated by the normative yaw rate calculating means (M1) with the avoiding exercise amount calculated by the avoiding exercise amount calculating means (M4);
Target assist current calculation means (M7) for calculating a target assist current to be supplied to the steering actuator (18) based on the deviation between the corrected standard yaw rate (γt) and the actual yaw rate (γ);
When the collision avoidance operation determination means (M2) determines the collision avoidance operation by the driver, the target calculated by the target assist current calculation means (M7) according to the steering torque (T) input to the steering wheel (11) by the driver Target assist current regulating means (M8) for regulating the upper limit value of the assist current;
A vehicle operation support device comprising: In a vehicle operation support device that supports a collision avoidance operation performed by a driver to avoid a collision with an obstacle (O) when the vehicle is running,
A collision avoidance operation determination means (M2) for determining a collision avoidance operation by the driver;
An obstacle detection means (M3) for detecting an obstacle (O) with which the host vehicle may collide,
When the collision avoidance operation determination means (M2) determines the collision avoidance operation by the driver, the avoidance exercise amount calculation calculates the avoidance exercise amount necessary to avoid the obstacle (O) detected by the obstacle detection means (M3). Means (M4);
Target assist current calculation means (M7) for calculating a target assist current to be supplied to the steering actuator (18) based on the avoidance exercise quantity calculated by the avoidance exercise quantity calculation means (M4);
When the collision avoidance operation determination means (M2) determines the collision avoidance operation by the driver, the target calculated by the target assist current calculation means (M7) according to the steering torque (T) input to the steering wheel (11) by the driver Target assist current regulating means (M8) for regulating the upper limit value of the assist current;
A vehicle operation support device comprising: The target assist current restricting means (M8) is configured so that the direction of the steering torque (T) input to the steering wheel (11) by the driver is the same direction as the direction of the target assist current compared to the reverse direction. The vehicle operation support device according to claim 1, wherein an upper limit value of the assist current is set low.

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