JP2020069864A - Steering control device - Google Patents

Abstract

To provide a steering control device capable of suppressing inappropriate adjustment of a road surface reaction force transmitted to a steering wheel.SOLUTION: A foundation reaction force calculation part 82 includes a current axial force calculation part 83 which calculates a current axial force Fer, an angle axial force calculation part 84 which calculates an angle axial force Fib, and a distribution axial force calculation part 85 which calculates a distribution axial force in which the current axial force Fer, the angle axial force Fib and a sensor axial force Fse are distributed with predetermined ratios as a reaction force component Fir. The distribution axial force calculation part 85 adds a value obtained by multiplying the angle axial force Fib by an angle distribution gain, a value obtained by multiplying the current axial force Fer by a current distribution gain and a value obtained by multiplying the sensor axial force Fse by a sensor distribution gain, and thereby calculates a reaction force component Fir. Regarding each of the distribution gains, when a state quantity that is a foundation to calculate the axial force is abnormal, the distribution gain by which the axial force on the basis of the abnormal state quantity is multiplied is set to be small compared to the case where there is no abnormality.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a steering control device.

  BACKGROUND ART Conventionally, as a vehicle steering device, an electric power steering device (EPS) is known in which an assist mechanism using a motor as a drive source applies an assist force for assisting the steering operation to the steering mechanism. There is a steering control device that controls the EPS as described above that calculates an assist command value so that a larger assist force is applied to the steering mechanism based on an increase in the steering torque input to the steering mechanism (for example, , Patent Document 1).

  By the way, in the EPS, the road surface reaction force, which is the force that the steered wheels receive from the road surface, is transmitted to the steering wheel via the steering mechanism. Then, the driver can grasp the road surface information such as the friction coefficient (μ) and the unevenness of the road surface from the magnitude and change of the road surface reaction force transmitted to the steering wheel. As described above, although the road surface reaction force can transmit road surface information to the driver, for example, vibration and the like which are not necessary for grasping the road surface reaction force are also transmitted to the steering wheel, which may lead to deterioration of steering feeling. There is.

  Therefore, for example, in Patent Document 2, the first assist component based on the steering torque and the second assist component based on the execution of the angle feedback control that causes the rotation angle of the rotating shaft that can be converted to the turning angle of the steered wheels to follow the target rotation angle A steering control device that calculates an assist command value based on an assist component is disclosed. By applying an assisting force including such a second assist component to the steering mechanism, the actual turning angle follows the target turning angle, so that the vibration transmitted from the turning wheels to the steering wheel, etc. It can be suppressed, and the steering feeling can be improved.

  Further, the steering control device uses a model (steering model) that represents the relationship between the torque and the rotation angle of the rotating shaft that rotates with the rotation of the steering wheel when calculating the target rotation angle. Then, the steering control device detects the axial force acting on the steered shaft as a force against the steering operation according to the road reaction force by the axial force sensor, and the axial force, the steering torque, and the first assist component are detected. The input torque is calculated based on, and the rotation angle when the input torque is input to the model is calculated as the target rotation angle. As a result, the target rotation angle, that is, the second assist component, changes due to the change in the axial force according to the road surface condition. Therefore, by adding the axial force to the calculation of the input torque as in Patent Document 2, it is possible to improve the steering feeling while transmitting the road surface information to the driver through the change of the second assist component (assist command value). it can.

JP, 2011-111080, A JP, 2014-943, A

  However, in the configuration of Patent Document 2, for example, when an abnormality occurs in the axial force sensor, the axial force does not become a value that accurately reflects the road surface reaction force, and the assist command value calculated using the axial force. Also becomes an abnormal value. Therefore, there is a possibility that the road reaction force transmitted to the steering wheel cannot be properly adjusted through the change of the assist command value.

  It should be noted that such a problem is not limited to the configuration in which the assist command value is calculated using the second assist component based on the execution of the angle feedback control, but similarly occurs when the axial force is used as the basis for calculating the assist command value. obtain. Further, not only when the axial force is detected by the axial force sensor, but also when the axial force is estimated based on various state quantities acquired by the steering control device, when abnormality occurs in these various state quantities, etc. Can have similar problems.

  An object of the present invention is to provide a steering control device that can prevent inappropriate adjustment of a road surface reaction force transmitted to a steering wheel.

  A steering control device that solves the above-described problem is directed to a steering device that applies an assist force for assisting a steering operation to a steering mechanism by an assist mechanism that uses a motor as a drive source, and a first assist component based on a steering torque. And a foundation for calculating a basic reaction force including at least one of a plurality of types of axial forces acting on the steered shaft to which the steered wheels are coupled and a tire force acting on the steered wheels. A reaction force calculation unit, and a target rotation angle calculation unit that calculates a target rotation angle that is a target of the rotation angle of the rotary shaft that can be converted into the turning angle of the steered wheels using the reaction force component based on the basic reaction force. A second assist component calculation unit that calculates a second assist component by executing angle feedback control based on the rotation angle and the target rotation angle, and the first assist component and the second assist component. Which controls the operation of the motor so as to generate an assist force corresponding to an assist command value based on the above, wherein the basic reaction force calculation unit is one of the acquired plurality of types of axial force and the tire force. Is abnormal, compared to the case where any of the plurality of types of axial force and the tire force is not abnormal, the basic reaction force so that the contribution rate of the abnormal force to the basic reaction force becomes low. Calculate

  A steering control device for solving the above-mentioned problems is directed to a steering device that applies an assisting force for assisting a steering operation to a steering mechanism by an assist mechanism using a motor as a drive source, and a steering torque to be input to the steering mechanism. A torque command value calculation unit that calculates a torque command value that is a target value of the first assist component calculation unit that calculates a first assist component by executing torque feedback control based on the steering torque and the torque command value. Based on the basic reaction force, a basic reaction force calculation unit that calculates a basic reaction force including at least one of a plurality of types of axial forces that act on the steered shaft to which the steering wheel is coupled and a tire force that acts on the steered wheel. A target rotation angle calculation unit that calculates a target rotation angle that is a target of the rotation angle of the rotation shaft that can be converted into the steered angle of the steered wheels using the reaction force component and the first assist component. , A second assist component calculator that calculates a second assist component by executing angle feedback control based on the rotation angle and the target rotation angle, and an assist force corresponding to an assist command value based on the second assist component is generated. The operation of the motor is controlled so as to occur, the basic reaction force calculation unit, when any of the acquired axial force and tire force of the plurality of types is abnormal, the plurality of types. The basic reaction force is calculated so that the contribution rate of the abnormal force to the basic reaction force is lower than that in the case where either the axial force of 1 or the tire force is not abnormal.

  A steering control device for solving the above-mentioned problems is directed to a steering shaft to which a steered wheel is connected, by controlling a steering device that applies an assist force for assisting a steering operation to a steering mechanism by an assist mechanism using a motor as a drive source. Using a basic reaction force calculation unit that calculates a basic reaction force including at least one of a plurality of types of axial force that acts on the steering wheel and a tire force that acts on the steered wheels, and a reaction force component based on the basic reaction force. A torque command value calculation unit that calculates a torque command value that is a target value of the steering torque to be input to the steering mechanism, and an assist command that calculates an assist command value by executing the torque feedback control based on the steering torque and the torque command value. A basic value calculation unit for controlling the operation of the motor so that an assist force corresponding to the assist command value is generated. In the case where any of the plurality of types of axial force and the tire force acquired is abnormal, compared to the case where any of the plurality of types of axial force and the tire force is not abnormal, the abnormal force The basic reaction force is calculated so that the contribution rate to the basic reaction force becomes low.

  According to each of the above configurations, the assist command value changes according to a change in the basic reaction force (reaction force component) according to the road surface condition. In the above configuration, when either the axial force or the tire force is abnormal, the influence (contribution) of the abnormal axial force or the tire force on the value of the basic reaction force becomes small. Force) can be suppressed from becoming an abnormal value. Therefore, even if the road surface reaction force transmitted to the steering wheel is adjusted by changing the assist command value, it is possible to prevent the adjustment from being inappropriate.

  In the steering control device, the basic reaction force calculation unit, when any of the plurality of types of the acquired axial force and the tire force is abnormal, the contribution ratio of the abnormal force to the basic reaction force is It is preferable to calculate the basic reaction force so as to be zero.

  According to the above configuration, since the influence of the abnormal axial force or the tire force on the value of the basic reaction force is eliminated, it is possible to preferably suppress the assist command value from becoming an abnormal value. Therefore, it is possible to preferably suppress inappropriate adjustment of the road surface reaction force transmitted to the steering wheel.

  In the steering control device, the basic reaction force calculation unit, when any of the acquired plurality of types of axial force and the tire force is abnormal, one of the plurality of types of axial force and the tire force. It is preferable to calculate the basic reaction force so that the contribution rate of the force other than the abnormal force to the basic reaction force is higher than that in the case where is not abnormal.

  According to the above configuration, it is possible to suppress a change in the magnitude of the assist command value before and after an abnormality occurs in any of a plurality of types of axial force and tire force, and reduce the driver's feeling of discomfort.

  According to the present invention, it is possible to prevent inappropriate adjustment of the road surface reaction force transmitted to the steering wheel.

1 is a schematic configuration diagram of an electric power steering device according to a first embodiment. The block diagram of the steering control device of a 1st embodiment. 3 is a block diagram of a reaction force component calculation unit according to the first embodiment. FIG. The block diagram of the reaction force component calculation part of 2nd Embodiment. The block diagram of the assist command value operation part of a 3rd embodiment. The block diagram of the steering control device of a 4th embodiment.

(First embodiment)
Hereinafter, a first embodiment of the steering control device will be described with reference to the drawings.
As shown in FIG. 1, an electric power steering device (EPS) 1 as a steering device to be controlled includes a steering mechanism 4 that steers steered wheels 3 based on an operation of a steering wheel 2 by a driver. . The EPS 1 also includes an assist mechanism 5 that applies an assist force to the steering mechanism 4 to assist the steering operation, and a steering control device 6 that controls the operation of the assist mechanism 5.

  The steering mechanism 4 includes a steering shaft 11 to which the steering wheel 2 is fixed, a rack shaft 12 as a steering shaft connected to the steering shaft 11, and a cylindrical rack housing into which the rack shaft 12 is reciprocally inserted. 13 and a rack and pinion mechanism 14 that converts the rotation of the steering shaft 11 into the reciprocating motion of the rack shaft 12. The steering shaft 11 is configured by connecting a column shaft 15, an intermediate shaft 16, and a pinion shaft 17 in order from the side where the steering wheel 2 is located.

  The rack shaft 12 and the pinion shaft 17 are arranged in the rack housing 13 with a predetermined crossing angle. The rack and pinion mechanism 14 is configured by meshing rack teeth 12a formed on the rack shaft 12 and pinion teeth 17a formed on the pinion shaft 17. Further, tie rods 19 are rotatably connected to both ends of the rack shaft 12 via rack ends 18 formed of ball joints provided at the shaft ends thereof. The tip of the tie rod 19 is connected to a knuckle (not shown) to which the steered wheels 3 are attached. Therefore, in the EPS 1, the rotation of the steering shaft 11 associated with the steering operation is converted into the axial movement of the rack shaft 12 by the rack and pinion mechanism 14, and this axial movement is transmitted to the knuckle through the tie rods 19. The steered angle of the steered wheels 3, that is, the traveling direction of the vehicle is changed.

  The assist mechanism 5 includes a motor 21 that is a drive source, a transmission mechanism 22 that transmits the rotation of the motor 21, and a conversion mechanism 23 that converts the rotation transmitted via the transmission mechanism 22 into the reciprocating motion of the rack shaft 12. I have it. Then, the assist mechanism 5 transmits the rotation of the motor 21 to the conversion mechanism 23 via the transmission mechanism 22 and converts the rotation of the rack shaft 12 into reciprocation by the conversion mechanism 23, thereby applying an assist force to the steering mechanism 4. .. A three-phase brushless motor is adopted as the motor 21 of this embodiment, a belt mechanism is adopted as the transmission mechanism 22, and a ball screw mechanism is adopted as the conversion mechanism 23.

  A torque sensor 41 that detects a steering torque Th applied to the steering shaft 11 by the steering of the driver is connected to the steering control device 6. A left front wheel sensor 42l and a right front wheel sensor 42r provided on a hub unit 42 that rotatably supports the steered wheels 3 via a drive shaft (not shown) are connected to the steering control device 6. The left front wheel sensor 42l and the right front wheel sensor 42r detect the wheel speeds Vl and Vr of the steered wheels 3. The steering control device 6 of the present embodiment detects the average value of the wheel speeds Vl and Vr as the vehicle speed V. Further, the steering control device 6 is connected to a rotation sensor 43 that detects a motor angle θm of the motor 21 with a relative angle within a range of 360 °. The steering torque Th and the motor angle θm are detected as positive values when steering in one direction (right in this embodiment) and negative values when steering in another direction (left in this embodiment). To do. Further, the steering control device 6 is connected with an axial force sensor 45 that acquires a sensor axial force Fse that is a detected value of the axial force acting on the rack shaft 12. As the axial force sensor 45, for example, a sensor that detects the axial force based on the pressure change according to the stroke of the rack shaft 12 can be adopted. The steering control device 6 acquires the sensor axial force Fse in the torque dimension (N · m). Then, the steering control device 6 supplies drive power to the motor 21 based on each state amount input from each of these sensors, thereby operating the assist mechanism 5, that is, reciprocating the rack shaft 12 in the steering mechanism 4. Controls the assisting force applied in order to do so.

Next, the configuration of the steering control device 6 will be described.
As shown in FIG. 2, the steering control device 6 includes a microcomputer 51 that outputs a motor control signal Sm, and a drive circuit 52 that supplies drive power to the motor 21 based on the motor control signal Sm. A well-known PWM inverter having a plurality of switching elements (for example, FETs) is adopted in the drive circuit 52 of the present embodiment. The motor control signal Sm output from the microcomputer 51 defines the on / off state of each switching element. As a result, each switching element is turned on / off in response to the motor control signal Sm, and the energization pattern to the motor coil of each phase is switched, so that the DC power of the vehicle-mounted power supply 53 is converted to the three-phase drive power and the motor 21 is driven. Is output to. Each control block described below is realized by a computer program executed by the microcomputer 51, detects each state quantity at a predetermined sampling cycle (detection cycle), and performs the following operations at predetermined calculation cycles. Each arithmetic process shown in the control block is executed.

  The vehicle speed V, the steering torque Th, the motor angle θm, and the sensor axial force Fse are input to the microcomputer 51. In addition, the phase current values Iu, Iv, Iw of the motor 21 detected by the current sensor 55 provided on the connection line 54 between the drive circuit 52 and the motor coils of each phase are input to the microcomputer 51. .. Note that, in FIG. 2, for convenience of description, the connection line 54 of each phase and the current sensor 55 of each phase are collectively shown as one. Then, the microcomputer 51 outputs a motor control signal Sm based on each of these state quantities.

More specifically, the microcomputer 51 includes an assist command value calculation unit 61 that calculates the assist command value Ta * and a motor control signal calculation unit 63 that calculates the motor control signal Sm.
As will be described later, the assist command value calculation unit 61 has a first assist component Ta1 based on the steering torque Th and a second assist component Ta2 based on execution of angle feedback control that causes the pinion angle θp to follow the target pinion angle θp *. The assist command value Ta * corresponding to the assist force to be applied by the steering mechanism 4 is calculated based on the added value of.

  The motor control signal calculator 63 calculates target current values Id * and Iq *, which are target values of the drive current supplied to the motor 21, based on the assist command value Ta *. The target current values Id * and Iq * indicate the target current value on the d-axis and the target current value on the q-axis in the d / q coordinate system, respectively. The motor control signal calculation unit 63 calculates the q-axis target current value Iq * having a larger absolute value as the absolute value of the assist command value Ta * increases. The d-axis target current value Id * is basically zero. Then, the motor control signal calculation unit 63 executes current feedback control in the d / q coordinate system based on the target current values Id *, Iq *, the phase current values Iu, Iv, Iw, and the motor angle θm of the motor 21. By doing so, a control signal is generated.

  Specifically, the motor control signal calculation unit 63 maps the phase current values Iu, Iv, and Iw on the d / q coordinates based on the motor angle θm, so that the actual current of the motor 21 in the d / q coordinate system. A d-axis current value Id and a q-axis current value Iq, which are values, are calculated. Then, the motor control signal calculation unit 63 causes the d-axis and the d-axis current value Id to follow the d-axis target current value Id * and the q-axis current value Iq to follow the q-axis target current value Iq *. A target voltage value is calculated based on each current deviation on the q-axis, and a motor control signal Sm having a duty ratio based on the target voltage value is calculated. The q-axis current value Iq calculated in the process of generating the motor control signal Sm is output to the assist command value calculation unit 61.

  The motor control signal Sm calculated in this way is output to the drive circuit 52. As a result, the motor 21 is supplied with drive power from the drive circuit 52 according to the motor control signal Sm. Then, the motor 21 applies the assist force indicated by the assist command value Ta * to the steering mechanism 4.

Next, the configuration of the assist command value calculation unit 61 will be described.
The steering torque Th, the vehicle speed V, the motor angle θm, the sensor axial force Fse, and the q-axis current value Iq are input to the assist command value calculation unit 61. The assist command value calculator 61 calculates the assist command value Ta * based on these state quantities.

  Specifically, the assist command value calculation unit 61 calculates the first assist component calculation unit 71 that calculates the first assist component Ta1, the reaction force component calculation unit 72 that calculates the reaction force component Fir, and the target pinion angle θp *. The target pinion angle calculation unit 73 and the pinion angle calculation unit 74 that calculates the pinion angle θp are provided. Further, the assist command value calculation unit 61 calculates the second assist component Ta2 by executing the angle feedback control that causes the actual pinion angle θp to follow the target pinion angle θp *. Section) 75 and. Then, the assist command value calculation unit 61 calculates the assist command value Ta * based on the first assist component Ta1 and the second assist component Ta2.

  More specifically, the steering torque Th and the vehicle speed V are input to the first assist component calculator 71. The first assist component calculator 71 calculates the first assist component Ta1 which is a force for assisting the steering operation based on these state quantities. Specifically, the first assist component calculator 71 calculates the first assist component Ta1 having a larger absolute value as the absolute value of the steering torque Th increases and the vehicle speed V decreases. The first assist component Ta1 calculated in this way is output to the target pinion angle calculation unit 73 and the adder 76.

  The steering torque Th, the vehicle speed V, the sensor axial force Fse, and the target pinion angle θp * are input to the reaction force component calculation unit 72. The reaction force component calculation unit 72 calculates a reaction force component Fir, which is a force against the steering operation, based on these state quantities, as described later, and outputs it to the target pinion angle calculation unit 73.

  The steering torque Th, the vehicle speed V, the first assist component Ta1 and the reaction force component Fir are input to the target pinion angle calculation unit 73. The target pinion angle calculation unit 73 calculates the target pinion angle θp * as the target rotation angle of the pinion shaft 17, which is the rotation shaft that can be converted into the turning angle of the steered wheels 3, based on these state quantities. Specifically, the target pinion angle calculation unit 73 associates the input torque Tin *, which is a value obtained by adding the steering torque Th to the first assist component Ta1 and subtracting the reaction force component Fir, with the target pinion angle θp *. The target pinion angle θp * is calculated using the model (steering model) formula.

Tin * = C ・ θp * '＋ J ・ θhp''… (1)
This model formula defines the relationship between the torque and the rotation angle of the rotating shaft that rotates with the rotation of the steering wheel 2. Then, this model formula is expressed using a viscosity coefficient C that models the friction and the like of the EPS 1 and an inertia coefficient J that models the inertia of the EPS 1. The viscosity coefficient C and the inertia coefficient J are variably set according to the vehicle speed V. The target pinion angle θp * calculated in this way is output to the subtractor 77 and the reaction force component calculation unit 72.

  The motor angle θm is input to the pinion angle calculation unit 74. The pinion angle calculation unit 74 calculates a pinion angle θp indicating a rotation angle (steering angle) of the pinion shaft 17 based on the motor angle θm. Specifically, the pinion angle calculation unit 74 integrates (counts) the number of rotations of the motor 21 with the pinion angle θp when the rack shaft 12 is in the neutral position where the vehicle goes straight, as an origin (zero degree), The pinion angle θp is calculated as an absolute angle including a range exceeding 360 ° based on the rotation speed and the motor angle θm. The pinion angle θp calculated in this way is output to the subtractor 77.

  In the subtracter 77, the angle F / B control unit 75 receives an angle deviation Δθ obtained by subtracting the pinion angle θp from the target pinion angle θp *. The angle F / B control unit 75 calculates a second assist component Ta2, which is a force for assisting the steering operation, as a control amount for feedback-controlling the pinion angle θp to the target pinion angle θp * based on the angle deviation Δθ. Specifically, the second assist component Ta2 calculates the sum of the respective output values of the proportional element, the integral element, and the derivative element that receive the angular deviation Δθ as the basic reaction torque. The second assist component Ta2 calculated in this way is output to the adder 76.

  Then, the assist command value calculation unit 61 calculates, in the adder 76, a value obtained by adding the second assist component Ta2 to the first assist component Ta1 as the assist command value Ta *, and outputs it to the motor control signal calculation unit 63.

Next, the configuration of the reaction force component calculator 72 will be described.
The vehicle speed V, the sensor axial force Fse, the q-axis current value Iq, and the target pinion angle θp * are input to the reaction force component calculation unit 72. The reaction force component calculation unit 72 calculates the reaction force component Fir according to the axial force acting on the rack shaft 12 based on these state quantities and outputs it to the target pinion angle calculation unit 73.

  As shown in FIG. 3, the reaction force component calculation unit 72 includes an abnormality determination unit 81 that determines whether each input state quantity (signal) is abnormal, and a reaction force component Fir based on each state quantity. And a basic reaction force calculation unit 82 that calculates a basic reaction force.

  The vehicle speed V, the sensor axial force Fse, the q-axis current value Iq, and the target pinion angle θp * are input to the abnormality determination unit 81. The abnormality determination unit 81 receives an input by a method such as determining that there is an abnormality when, for example, each state quantity has an unacceptable value, or the amount of change from the previous value exceeds a preset threshold value. It is determined whether or not each state quantity is abnormal. Then, the abnormality determination unit 81 directly inputs the vehicle speed V, the sensor axial force Fse, the q-axis current value Iq, and the target pinion angle θp * together with the determination signal Sde indicating the determination result of the abnormality determination as the basic reaction force calculation unit 82. Output to.

  The basic reaction force calculation unit 82 includes a current axial force calculation unit 83 that calculates a current axial force (road surface axial force) Fer, and an angle axial force calculation unit 84 that calculates an angular axial force (ideal axial force) Fib. There is. The current axial force Fer and the angular axial force Fib are calculated in the torque dimension (N · m). Further, the basic reaction force calculation unit 82 reflects the axial force applied to the steered wheels 3 from the road surface (road surface information transmitted from the road surface), the current axial force Fer, the angular axial force Fib, and the sensor axis. A distribution axial force calculation unit 85 for calculating a distribution axial force obtained by distributing the force Fse at a predetermined ratio as a reaction force component Fir (basic reaction force) is provided.

  The q-axis current value Iq is input to the current axial force calculation unit 83. The current axial force calculation unit 83 is the estimated value of the axial force acting on the steered wheels 3 (transmitted force transmitted to the steered wheels 3), and the current axial force Fer in which the road surface information is reflected is the q-axis current value Iq. Calculate based on. Specifically, the current axial force calculator 83 balances the torque applied from the motor 21 to the rack shaft 12 and the steering torque Th with the torque corresponding to the force applied to the steered wheels 3 from the road surface. The calculation is performed such that the larger the absolute value of the shaft current value Iq, the larger the absolute value of the current axial force Fer. The current axial force Fer calculated in this way is output to the distributed axial force calculation unit 85.

  The target pinion angle θp * and the vehicle speed V are input to the angular axial force calculation unit 84. The angular axial force calculation unit 84 sets the angular axial force Fib, which is an ideal value of the axial force acting on the steered wheels 3 (transmitted force transmitted to the steered wheels 3) and does not reflect road surface information, to the target pinion angle θp *. Calculate based on Specifically, the angular axial force calculation unit 84 performs calculation so that the absolute value of the angular axial force Fib increases as the absolute value of the target pinion angle θp * increases. Further, the angular axial force calculation unit 84 performs calculation so that the absolute value of the angular axial force Fib increases as the vehicle speed V increases. The angular axial force Fib calculated in this way is output to the distributed axial force calculating unit 85.

  In addition to the determination signal Sde, the current axial force Fer and the angular axial force Fib, the sensor axial force Fse is input to the distributed axial force calculation unit 85. The distribution axial force calculation unit 85 includes a current distribution gain Ger indicating the distribution ratio of the current axial force Fer, an angle distribution gain Gib indicating the distribution ratio of the angular axial force Fib, and a sensor distribution gain indicating the distribution ratio of the sensor axial force Fse. Gse is set in advance by experiments or the like. The current distribution gain Ger, the angle distribution gain Gib, and the sensor distribution gain Gse are variably set according to the vehicle speed V. Then, the distribution axial force calculation unit 85 multiplies the angular axial force Fib by the angle distribution gain Gib, the current axial force Fer by the current distribution gain Ger, and the sensor axial force Fse by the sensor distribution gain Gse. The reaction force component Fir is calculated by adding the calculated values. That is, the basic reaction force calculation unit 82 of the present embodiment acquires three axial forces of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse, and based on these three axial forces, the reaction force component Fir ( Basic reaction force) is calculated.

  In the steering control device 6 configured as above, the target pinion angle θp * is calculated by adding the reaction force component Fir (axial force) to the input torque Tin *, and the target pinion angle θp * is followed by the pinion angle θp. The second assist component Ta2 for causing it to be included in the assist command value Ta *. Therefore, the road surface reaction force transmitted to the steering wheel 2 can be adjusted through the change of the second assist component Ta2 (assist command value Ta *) according to the road surface state, and the vibration and the like are suppressed while transmitting the road surface information to the driver. Therefore, it is possible to improve the steering feeling. However, if an abnormality occurs in the axial force sensor 45, for example, the reaction force component Fir based on the sensor axial force Fse, and by extension, the assist command value Ta * may become an abnormal value.

  In this regard, in the present embodiment, the distribution gains Ger, Gib, and Gse are set to different values according to the determination result indicated by the determination signal Sde. Specifically, when the acquired state quantity is abnormal, the distribution gain by which the axial force based on the abnormal state quantity is multiplied is smaller than that when there is no abnormality, and each state quantity without abnormality is The distribution gain by which the axial force based on is multiplied is set to be large. That is, the basic reaction force calculation unit 82 of the present embodiment determines that the axial force is abnormal when the state quantity for calculating the axial force is abnormal. When the acquired state quantities are abnormal, the distribution gains Ger, Gib, and Gse have a contribution rate to the reaction force component Fir of the axial force (abnormal axial force) based on the abnormal state quantities. It is set so as to become lower and the contribution rate of the axial force (normal axial force) based on each state quantity having no abnormality to the reaction force component Fir becomes higher.

  As an example, the current distribution gain Ger is "0.3" when each state quantity is normal, "0" when the q-axis current value Iq is abnormal, and other than the q-axis current value Iq (target pinion). If at least one of the angle θp *, the vehicle speed V, and the sensor axial force Fse) is abnormal, “0.45” is set. Further, the angle distribution gain Gib is "0.45" when each state quantity is normal, "0" when at least one of the target pinion angle θp * and the vehicle speed V is abnormal, and the target pinion angle θp. When the value other than * and the vehicle speed V (at least one of the q-axis current value Iq and the sensor axial force Fse) is abnormal, "0.6" is set. Further, the sensor distribution gain Gse is “0.7” when each state quantity is normal, “0” when the sensor axial force Fse is abnormal, and other than the sensor axial force Fse (target pinion angle θp * If at least one of the vehicle speed V and the q-axis current value Iq) is abnormal, the value is set to "0.9". The values of the distribution gains Ger, Gib, and Gse can be changed as appropriate, and the sum of them can be set to "1", or can be set to be larger or smaller than "1". Good.

Next, the operation and effect of this embodiment will be described.
(1) If any of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse is abnormal, the basic reaction force calculation unit 82 multiplies the abnormal axial force by the distribution gains Ger and Gib. , Gse to zero, the contribution ratio of the abnormal axial force to the reaction force component Fir (basic reaction force) is set to zero. Specifically, the basic reaction force calculation unit 82, if there is no abnormality in the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse, the current axial force Fer is 30% and the angular axial force Fib is 45%. , The sensor axial force Fse is distributed at a rate of 70% to calculate the reaction force component Fir. Here, assuming that the value of the sensor axial force Fse becomes abnormal, for example, the basic reaction force calculation unit 82 determines that the current axial force Fer is 45%, the angular axial force Fib is 60%, and the sensor axial force Fse is 0%. And the reaction force component Fir is calculated. This eliminates the influence (contribution) of the abnormal axial force on the value of the reaction force component Fir, so that it is possible to preferably suppress the assist command value Ta * from becoming an abnormal value. Therefore, even if the road surface reaction force transmitted to the steering wheel 2 is adjusted by changing the assist command value Ta *, it is possible to preferably prevent the adjustment from being inappropriate.

  (2) When any of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse is abnormal, the basic reaction force calculation unit 82 multiplies the axial force other than the abnormal axial force by a distribution gain. By increasing Ger, Gib, and Gse, the contribution rate of the axial force other than the abnormal axial force to the reaction force component Fir is increased. As a result, the magnitude of the steering reaction force can be prevented from changing before and after an abnormality occurs in any of the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse, and the driver's discomfort is reduced. it can.

(Second embodiment)
Next, a second embodiment of the steering control device will be described with reference to the drawings. For the sake of convenience of explanation, the same components are designated by the same reference numerals as those of the first embodiment, and the description thereof will be omitted.

  As shown in FIG. 4, the target pinion angle θp *, the vehicle speed V, the q-axis current value Iq, and the tire force Ft are input to the reaction force component calculation unit 72 of the present embodiment, but the sensor axial force Fse is not input. The tire force Ft is the load in the vehicle front-rear direction (x direction), the load in the vehicle left-right direction (y direction), the load in the vehicle up-down direction (z direction), x detected by the hub unit 42 (see FIG. 1). It is a value (unit: Newton) based on at least one of the moment about the axis, the moment about the y axis, and the moment about the z axis.

  The vehicle speed V, the q-axis current value Iq, the target pinion angle θp *, and the tire force Ft are input to the abnormality determination unit 81 of the present embodiment. Then, the abnormality determination unit 81 determines the abnormality of each state quantity as in the first embodiment, and inputs the vehicle speed V, the q-axis current value Iq, the target pinion angle together with the determination signal Sde indicating the determination result. The θp * and the tire force Ft are directly output to the basic reaction force calculation unit 82.

  The basic reaction force calculation unit 82 of the present embodiment includes a torque conversion unit 91 and an output switching unit 92 in addition to the current axial force calculation unit 83, the angular axial force calculation unit 84, and the distributed axial force calculation unit 85. The current axial force calculation unit 83 and the angular axial force calculation unit 84 respectively calculate the current axial force Fer and the angular axial force Fib, and output them to the distributed axial force calculation unit 85, as in the first embodiment.

  The distribution axial force calculation unit 85 includes a distribution gain calculation unit 101 that calculates the current distribution gain Ger and the angle distribution gain Gib based on the vehicle speed V. The distribution gain calculation unit 101 of the present embodiment includes a map that defines the relationship between the vehicle speed V and the distribution gains Ger and Gib, and calculates the distribution gains Ger and Gib according to the vehicle speed V by referring to the map. To do. When the vehicle speed V is high, the current distribution gain Ger has a larger value than when it is small, and when the vehicle speed V is large, the angle distribution gain Gib has a smaller value than when it is small. In the present embodiment, the value is set so that the sum of the distribution gains Ger and Gib is “1”. The current distribution gain Ger thus calculated is output to the multiplier 102, and the angle distribution gain Gib is output to the multiplier 103.

  The current axial force Fer is input to the multiplier 102, and the angular axial force Fib is input to the multiplier 103. Then, the distributed axial force calculation unit 85 multiplies the current axial force Fer by the current distribution gain Ger in the multiplier 102, multiplies the angular axial force Fib by the angle distribution gain Gib in the multiplier 103, and these in the adder 104. And the distributed axial force Fd is calculated. The distributed axial force Fd calculated in this way is output to the output switching unit 92.

  The tire force Ft is input to the torque conversion unit 91. The torque conversion unit 91 calculates the tire torque Tt around the pinion shaft 17 by multiplying the tire force Ft by a conversion coefficient Kp based on the rotation speed ratio of the rack and pinion mechanism 14. The tire torque Tt calculated in this way is output to the output switching unit 92.

  The determination signal Sde is input to the output switching unit 92 in addition to the distributed axial force Fd and the tire torque Tt. Based on the determination signal Sde, the output switching unit 92 outputs the distributed axial force Fd as the reaction force component Fir when there is no abnormality in each state amount that is the basis of the distributed axial force Fd, and outputs the distributed axial force Fd as a reaction force component Fir. When at least one is abnormal, the tire torque Tt is output as the reaction force component Fir. That is, the basic reaction force calculation unit 82 of the present embodiment acquires three forces of the current axial force Fer, the angular axial force Fib, and the tire force Ft, and the distribution axis based on the current axial force Fer and the angular axial force Fib. The force Fd or the tire torque Tt based on the tire force Ft is output as the reaction force component Fir. Further, the basic reaction force calculation unit 82 switches to the tire torque Tt when there is an abnormality in each state amount that is the basis of the distributed axial force Fd, thereby reducing the contribution rate of the abnormal axial force to the reaction force component Fir. Then, the reaction force component Fir is calculated (zeroed).

As described above, this embodiment has the same operation and effect as the operation and effect of (1) of the first embodiment.
(Third Embodiment)
Next, a third embodiment of the steering control device will be described with reference to the drawings. For the sake of convenience of explanation, the same components are designated by the same reference numerals as those of the first embodiment, and the description thereof will be omitted.

  As shown in FIG. 5, the first assist component calculator 71 of the present embodiment calculates the torque command value Th1 * and the torque command value calculator 111, and calculates the first assist component Ta1 by executing the torque feedback calculation. A torque feedback control unit (hereinafter, torque F / B control unit) 112 is provided.

  Specifically, the torque command value calculation unit 111 is supplied with the drive torque Tc obtained by adding the first assist component Ta1 to the steering torque Th in the adder 113. The torque command value calculation unit 111 calculates a torque command value Th1 *, which is a target value of the steering torque Th that the driver should input for the drive torque Tc, based on the drive torque Tc. Specifically, the torque command value calculation unit 111 calculates a torque command value Th1 * that has a larger absolute value as the drive torque Tc has a larger absolute value.

  The torque F / B control unit 112 receives the torque deviation ΔT1 obtained by subtracting the torque command value Th1 * from the steering torque Th in the subtractor 114. Then, the torque F / B control unit 112 calculates the first assist component Ta1 as a control amount for feedback controlling the steering torque Th to the torque command value Th1 * based on the torque deviation ΔT1. Specifically, the torque F / B control unit 112 calculates, as the first assist component Ta1, the sum of the output values of the proportional element, the integral element, and the derivative element that receive the torque deviation ΔT1 as an input.

  The first assist component Ta1 calculated in this way is output to the target pinion angle calculation unit 73 and the adder 76 as well as to the adder 113 as in the first embodiment. Accordingly, the target pinion angle θp * is calculated in the target pinion angle calculation unit 73, as in the first embodiment. Further, the adder 76 adds the first assist component Ta1 and the second assist component Ta2 to calculate the assist command value Ta *.

  Then, as in the first embodiment, when there is an abnormality in the state quantity, the reaction force component calculation unit 72 responds to the reaction force component Fir (basic reaction force) of the axial force based on the abnormal state quantity. The reaction force component Fir is calculated so that the contribution rate becomes low.

As described above, the present embodiment has the same actions and effects as the actions and effects of (1) and (2) of the first embodiment.
(Fourth Embodiment)
Next, a fourth embodiment of the steering control device will be described with reference to the drawings. For the sake of convenience of explanation, the same components are designated by the same reference numerals as those of the first embodiment, and the description thereof will be omitted.

  As shown in FIG. 6, the assist command value calculation unit 61 of the present embodiment includes a reaction force component calculation unit 72, a pinion angle calculation unit 74, a torque command value calculation unit 121, and a torque F / B control unit 122. The first assist component calculator 71 and the target pinion angle calculator 73 are not provided. The pinion angle calculation unit 74 calculates the pinion angle θp as in the first embodiment.

  The vehicle speed V, the sensor axial force Fse, the q-axis current value Iq, and the pinion angle θp are input to the reaction force component calculation unit 72. That is, the pinion angle θp is input to the reaction force component calculation unit 72 of the present embodiment in place of the target pinion angle θp *. Then, the reaction force component calculation unit 72 is similar to the first embodiment except that the angle axial force calculation unit 84 calculates the angular axial force Fib based on the pinion angle θp instead of the target pinion angle θp *. The reaction force component Fir is calculated.

  The torque command value calculation unit 121 calculates a torque command value Th2 * that has a larger absolute value as the absolute value of the reaction force component Fir is larger. The torque F / B control unit 122 receives the torque deviation ΔT2 obtained by subtracting the torque command value Th2 * from the steering torque Th in the subtractor 123. Then, the torque F / B control unit 122 calculates the assist command value Ta * as a control amount for feedback controlling the steering torque Th to the torque command value Th2 * based on the torque deviation ΔT2. Specifically, the torque F / B control unit 122 calculates the sum of the output values of the proportional element, the integral element, and the derivative element that receive the torque deviation ΔT2 as the assist command value Ta *.

  Then, as in the first embodiment, when there is an abnormality in the state quantity, the reaction force component calculation unit 72 responds to the reaction force component Fir (basic reaction force) of the axial force based on the abnormal state quantity. The reaction force component Fir is calculated so that the contribution rate becomes low.

As described above, the present embodiment has the same actions and effects as the actions and effects of (1) and (2) of the first embodiment.
This embodiment can be modified and implemented as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

  In the third embodiment, the assist command value Ta * is calculated by adding the first assist component Ta1 and the second assist component Ta2, but the invention is not limited to this. For example, the second assist component Ta2 is used as it is as an assist command. It may be calculated as the value Ta *.

  In the first, third, and fourth embodiments described above, the reaction force component Fir is calculated based on the current axial force Fer, the angular axial force Fib, and the sensor axial force Fse. Additionally or alternatively, the reaction force component Fir may be calculated using the axial force estimated based on another state quantity. Such other axial forces include, for example, the vehicle state quantity axial force calculated based on the yaw rate and lateral acceleration, the tire axial force calculated based on the tire force Ft, and the like. Similarly, in the second embodiment described above, the distributed axial force Fd may be calculated using another state quantity.

  In the second embodiment, the distributed axial force Fd or the tire torque Tt is output as the reaction force component Fir according to the result of the abnormality determination. However, the configuration for switching the output according to the determination result is not limited to this, and for example, the angular axial force Fib and the current axial force Fer are input to the output switching unit 92, and in normal operation, either the axial axial force Fer or the angular axial force Fib is input. One of them may be output, and the other may be output when the state quantity that is the basis of the one is abnormal.

  In the first, third and fourth embodiments, when any one of the current axial force Fer, the angular axial force Fib and the sensor axial force Fse is abnormal, the distribution gain Ger is multiplied by the abnormal axial force. , Gib, Gse are set to zero, but the distribution gains Ger, Gib, Gse may be set to values larger than zero as long as the distribution gains Ger, Gib, and Gse are smaller than those in the normal case. As a result, the influence of the abnormal axial force on the value of the reaction force component Fir is reduced, so that the assist command value Ta * can be prevented from becoming an abnormal value.

  In the first, third and fourth embodiments, when any of the current axial force Fer, the angular axial force Fib and the sensor axial force Fse is abnormal, the axial force other than the abnormal axial force is multiplied. Although the distribution gains Ger, Gib, Gse to be increased are not limited to this, the distribution gains Ger, Gib, Gse for multiplying the axial force other than the abnormal axial force may not be changed.

  In each of the above-described embodiments, the abnormality determination unit 81 determines an abnormality in the value of each state quantity itself, and when the state quantity for calculating the axial force has an abnormality, it is determined that the axial force is abnormal. However, the present invention is not limited to this, and in addition to or instead of the same determination, for example, an abnormality in the calculation processing (for example, the calculation processing of the current axial force calculation unit 83 that calculates the current axial force Fer based on the q-axis current value Iq) is determined. However, whether or not the axial force is abnormal may be determined based on the determination result, and the method for determining abnormality can be changed as appropriate.

In each of the above embodiments, the current axial force Fer is calculated based on the q-axis current value Iq, but the present invention is not limited to this, and may be calculated based on the q-axis target current value Iq *, for example.
In the first to third embodiments described above, the angular axial force Fib is calculated based on the target pinion angle θp * and the vehicle speed V, but the present invention is not limited to this, and may be calculated based only on the target pinion angle θp *. . Similarly, in the fourth embodiment, the angular axial force Fib may be calculated based on only the pinion angle θp. Furthermore, the angular axial force Fib may be calculated by another method such as adding other parameters such as the steering torque Th and the vehicle speed V.

  In the second embodiment described above, the distribution axial force calculation unit 85 may calculate the distribution gains Ger and Gib in consideration of parameters other than the vehicle speed V. For example, in a vehicle in which a drive mode indicating a control pattern setting state such as an in-vehicle engine can be selected from a plurality of drive modes, the drive mode may be used as a parameter for setting the distribution gains Ger and Gib. In this case, the distribution axial force calculation unit 85 includes a plurality of maps having different tendencies with respect to the vehicle speed V for each drive mode, and by referring to the maps, the distribution gains Ger and Gib can be calculated.

  In each of the above-described embodiments, the reaction force component calculation unit 72 may calculate a value that takes into account a reaction force other than the distributed axial force Fd or the tire torque Tt as the reaction force component Fir. As such a reaction force, for example, when the absolute value of the steering angle of the steering wheel 2 approaches the steering angle threshold value, an end reaction force that is a reaction force against further cutting steering can be adopted. It should be noted that the steering angle threshold is, for example, a virtual rack end set on the neutral position side of a mechanical rack end position where axial movement of the rack shaft 12 is restricted by the rack end 18 coming into contact with the rack housing 13. The pinion angle θp at the position can be used.

  In each of the above-described embodiments, the target pinion is calculated by using the model formula in which the target pinion angle calculation unit 73 uses the spring coefficient K determined by the specifications of the suspension, the wheel alignment, and the like, in which a so-called spring term is added. The angle θp * may be calculated.

  In each of the above embodiments, the steering control device 6 controls the EPS 1 of a type in which the assist mechanism 5 applies the assist force to the rack shaft 12 via the transmission mechanism 22 and the conversion mechanism 23, but the present invention is not limited to this. For example, a steering device of a type that applies a motor torque to the column shaft 15 via a reduction mechanism may be a control target.

Next, the technical ideas that can be understood from the above-described embodiments and modifications will be added below.
(A) The steering control device in which the basic reaction force calculation unit calculates the distributed axial force or the tire force, which is the sum of the plurality of types of axial forces at respective individually set distribution ratios, as the basic reaction force.

  DESCRIPTION OF SYMBOLS 1 ... Electric power steering device (EPS), 2 ... Steering wheel, 3 ... Steering wheel, 4 ... Steering mechanism, 5 ... Assist mechanism, 6 ... Steering control device, 11 ... Steering shaft, 12 ... Rack shaft (steering shaft) , 17 ... Pinion shaft (rotating shaft), 21 ... Motor, 51 ... Microcomputer, 61 ... Assist command value calculation unit, 71 ... First assist component calculation unit, 72 ... Reaction force component calculation unit, 73 ... Target pinion angle calculation unit (Target rotation angle calculation unit), 74 ... Pinion angle calculation unit, 75 ... Angle F / B control unit (assist component calculation unit), 81 ... Abnormality determination unit, 82 ... Basic reaction force calculation unit, 83 ... Current axial force calculation .. 84. Angular axial force calculation unit, 85 ... Distributed axial force calculation unit, 91 ... Torque conversion unit, 92 ... Output switching unit, 101 ... Distribution gain calculation unit, 111, 121 ... Torque command value calculation unit, 112, 122 … Tor F / B control unit, Fd ... distributed axial force, Ft ... tire force, Fer ... current axial force, Fib ... angular axial force, Fir ... reaction force component (basic reaction force), Fse ... sensor axial force, Ger ... current distribution Gain, Gib ... Angle distribution gain, Gse ... Sensor distribution gain, Sde ... Judgment signal, Ta * ... Assist command value, Ta1 ... First assist component, Ta2 ... Second assist component, Th ... Steering torque, Th * ... Torque command Value, Tt ... Tire torque, θp ... Pinion angle (rotation angle), θp * ... Target pinion angle (target rotation angle).

Claims (5)

A steering device that applies an assist force for assisting the steering operation to the steering mechanism by an assist mechanism using a motor as a drive source is controlled,
A first assist component calculator that calculates the first assist component based on the steering torque;
A basic reaction force calculation unit that calculates a basic reaction force that includes at least one of a plurality of types of axial forces that act on the steered shaft to which the steered wheels are coupled and a tire force that acts on the steered wheels;
Using a reaction force component based on the basic reaction force, a target rotation angle calculation unit that calculates a target rotation angle that is a target of the rotation angle of the rotating shaft that can be converted into the steered angle of the steered wheels,
A second assist component calculator that calculates a second assist component by executing angle feedback control based on the rotation angle and the target rotation angle,
A steering control device that controls the operation of the motor so that an assist force corresponding to an assist command value based on the first assist component and the second assist component is generated,
The basic reaction force calculation unit, when any of the plurality of types of axial force and the tire force acquired is abnormal, as compared with the case where any of the plurality of types of axial force and the tire force is not abnormal. A steering control device that calculates the basic reaction force so that the contribution ratio of the abnormal force to the basic reaction force becomes low. A steering device that applies an assist force for assisting the steering operation to the steering mechanism by an assist mechanism using a motor as a drive source is controlled,
A torque command value calculation unit that calculates a torque command value that is a target value of the steering torque to be input to the steering mechanism;
A first assist component calculator that calculates a first assist component by executing torque feedback control based on the steering torque and the torque command value;
A basic reaction force calculation unit that calculates a basic reaction force that includes at least one of a plurality of types of axial forces that act on the steered shaft to which the steered wheels are coupled and a tire force that acts on the steered wheels;
A target rotation angle calculation unit that calculates a target rotation angle that is a target of the rotation angle of the rotating shaft that can be converted into the turning angle of the steered wheels by using the reaction force component based on the basic reaction force and the first assist component. ,
A second assist component calculator that calculates a second assist component by executing angle feedback control based on the rotation angle and the target rotation angle,
A steering control device that controls the operation of the motor so that an assist force corresponding to an assist command value based on the second assist component is generated,
The basic reaction force calculation unit, when any of the plurality of types of axial force and the tire force acquired is abnormal, as compared with the case where any of the plurality of types of axial force and the tire force is not abnormal. A steering control device that calculates the basic reaction force so that the contribution ratio of the abnormal force to the basic reaction force becomes low. A steering device that applies an assist force for assisting the steering operation to the steering mechanism by an assist mechanism using a motor as a drive source is controlled,
A basic reaction force calculation unit that calculates a basic reaction force that includes at least one of a plurality of types of axial forces that act on the steered shaft to which the steered wheels are coupled and a tire force that acts on the steered wheels;
Using a reaction force component based on the basic reaction force, a torque command value calculation unit that calculates a torque command value that is a target value of steering torque to be input to the steering mechanism,
An assist command value calculation unit that calculates an assist command value by executing torque feedback control based on the steering torque and the torque command value,
A steering control device for controlling the operation of the motor so that an assist force according to the assist command value is generated,
The basic reaction force calculation unit, when any of the plurality of types of axial force and the tire force acquired is abnormal, as compared with the case where any of the plurality of types of axial force and the tire force is not abnormal. A steering control device that calculates the basic reaction force so that the contribution ratio of the abnormal force to the basic reaction force becomes low. The steering control device according to any one of claims 1 to 3,
The basic reaction force calculation unit, when any of the acquired plurality of types of axial force and the tire force is abnormal, so that the contribution ratio of the abnormal force to the basic reaction force becomes zero. A steering control device that calculates the basic reaction force. The steering control device according to any one of claims 1 to 4,
The basic reaction force calculation unit, when any of the plurality of types of axial force and the tire force acquired is abnormal, as compared with the case where any of the plurality of types of axial force and the tire force is not abnormal. A steering control device that calculates the basic reaction force such that a contribution rate of a force other than the abnormal force to the basic reaction force becomes high.