JP6955197B2 - Steering control device - Google Patents

Description

The present invention relates to a steering control device.

Conventionally, there is a steering device in which an actuator using a motor as a drive source assists the driver in steering operation. As such a steering device, a first torque component based on the steering torque and a second torque component based on the rotation angle feedback control that makes the rotation angle of the rotation shaft that can be converted into the steering angle of the steering wheel follow the rotation angle command value. It is known that the torque command value is calculated by adding them together, and the motor is controlled so that the motor torque indicated by the torque command value is output.

For example, in the electric power steering device of Patent Document 1, the pinion angle command value, which is the rotation angle command value, is calculated based on the ideal model of the pinion angle with respect to the input torque, and the second torque component is calculated by executing the rotation angle feedback control. .. This ideal model is a model of the steering mechanism using the spring component, the viscous component, and the inertial component of the steering mechanism, and the steering angle generated by steering by the input torque is a natural feeling of the driver. It is set to be in line with. By including the second torque component obtained through the rotation angle feedback control in the torque command value, the actual steering angle follows the target steering angle corresponding to the rotation angle command value. The steering wheel is steered according to the driver's intention by the operation. As a result, the steering characteristics indicated by the relationship between the steering angle and the steering reaction force felt by the driver can be made excellent by accurately reflecting the steering intention of the driver.

Further, for example, in the electric power steering device of Patent Document 2, a value obtained by subtracting a reaction force component corresponding to the steering angle from the first torque component based on the steering torque is calculated as the final first torque component. By subtracting the reaction force component from the first torque component in this way, the output motor torque is reduced, so that a steering feeling corresponding to the reaction force component can be given to the driver. Then, in the same document, the reaction force component is provided with a hysteresis component for a change in the steering angle, and the reaction force component is calculated according to the steering state, steering angle, etc. of whether the steering is cut-in steering or turning-back steering. Therefore, a suitable steering feeling is created according to the steering operation, and excellent steering characteristics are realized.

International Publication No. 2012/133590 Japanese Unexamined Patent Publication No. 2015-63291 Japanese Unexamined Patent Publication No. 9-221053

By the way, in recent years, a steering control device that executes control for assisting a driver's driving has been put into practical use, and as such driving support control, for example, as described in Patent Document 3, a vehicle travels. There is a lane keep assist control that keeps the driving lane inside. However, in the steering control device that realizes excellent steering characteristics by adding various compensation components to the first torque component (basic component) based on the steering torque as in Patent Documents 1 and 2, the driving support control is also performed. It is hard to say that the configuration to be executed has been sufficiently developed, and there has been a demand for the development of a technology capable of effectively executing driving support control while realizing excellent steering characteristics.

An object of the present invention is to provide a steering control device capable of effectively executing driving support control while realizing excellent steering characteristics.

The steering control device that solves the above problems targets a steering device to which a motor torque for reciprocating the steering shaft of the steering mechanism is applied by an actuator that uses a motor as a drive source, and the steering torque transmitted to the steering mechanism. The first torque component calculation unit that calculates the first torque component based on, and the basic rotation angle component of the rotation shaft that can be converted into the steering angle of the steering wheel based on the steering torque and the first torque component. A rotation angle command value that is a target of the rotation angle of the rotation shaft based on the rotation angle component calculation unit, the basic rotation angle component, and the operation support rotation angle component input from the operation support control device provided externally. A rotation angle command value calculation unit that calculates the above, and a second torque component calculation unit that executes rotation angle feedback control based on the rotation angle command value to calculate the second torque component, and the first torque component The operation of the actuator is controlled based on the torque command value based on the value obtained by adding the second torque components, and the basic rotation angle component is used when the driving support control by the driving support control device is prioritized. The calculation is made so that the ratio of the change in the steering reaction force to the change in the rotation angle is larger than that in the non-priority state in which the driving support control is not prioritized.

Here, when the steering control device that calculates the second torque component based on the rotation angle feedback control executes the driving support control, the operation for providing the driving support to the basic rotation angle component based on the steering torque and the first torque component. It is conceivable to add the support rotation angle components to calculate the rotation angle command value of the rotation angle feedback control. However, since the basic rotation angle component is calculated so as to realize excellent steering characteristics, it cannot always be said that high responsiveness can be realized. Then, when the driving support control is executed, the steering torque transmitted to the steering mechanism changes by driving the motor based on the driving support rotation angle component regardless of whether or not the driver operates the steering. That is, the basic rotation angle component for realizing the steering characteristic excellent in the rotation angle command value is included. As a result, the operation of the actuator is controlled so as to realize excellent steering characteristics, which may affect the followability of the actual rotation angle with respect to the driving support rotation angle component.

Based on this point, in the above configuration, the basic rotation angle component is calculated so that the ratio of the change in the steering reaction force to the change in the rotation angle is larger when the driving support control is prioritized than when the driving support control is not prioritized. That is, the steering characteristic indicated by the relationship between the rotation angle and the steering reaction force shows high rigidity when the driving support control is prioritized, so that high responsiveness to the steering by the driving support control can be realized. In other words, the fact that the ratio of the change in the steering reaction force to the change in the rotation angle becomes large as the steering characteristic means that even if a large steering torque is input, a small basic rotation angle component is calculated, and the second torque component. The ratio of the basic rotation angle component to the total becomes small. As a result, the amount of control for achieving excellent steering characteristics is reduced, so that the influence on the followability of the actual rotation angle with respect to the driving support rotation angle component can be reduced, and a high response to steering by driving support control can be achieved. Can realize sex. Further, by making the steering characteristics show high rigidity when the driving support control is prioritized, excellent steering characteristics can be realized when the driving support control is not prioritized.

The steering control device includes an input torque calculation unit that calculates an input torque transmitted to the rotation shaft based on the addition value of the steering torque and the first torque component, and the basic rotation angle component calculation unit is the input. The basic rotation angle component is calculated based on the ideal model of the rotation angle with respect to torque, and the ideal model is a normal ideal model used when the driving support control is not prioritized and a priority of the driving support control. The normal ideal model and the driving support ideal model include a spring term based on a rotation angle, a viscosity term based on a rotation angle velocity, and each control output of the spring term and the viscosity term. The spring component and the viscous component are expressed by including an inertial term based on the value obtained by subtracting the input torque from the input torque, and the spring coefficient constituting the spring term of the driving support ideal model is the spring term of the normal ideal model. It is preferable that the spring coefficient is set to be larger than the spring coefficient constituting the above.

According to the above configuration, the basic rotation angle component is calculated based on the driving support ideal model having a large spring term coefficient when the driving support control is prioritized, that is, the basic rotation angle component is calculated based on the ideal model having a large spring component. As a result, the feeling of rigidity is enhanced, and therefore, steering characteristics with high rigidity can be suitably realized.

In the steering control device, a reaction force component calculation unit that calculates a reaction force component with respect to the first torque component based on the rotation angle, and a reaction force gain calculation unit that calculates a reaction force gain multiplied by the reaction force component are provided. It is preferable that the reaction force gain is calculated to a larger value when the driving support control is prioritized than when the driving support control is not prioritized.

According to the above configuration, since the gain multiplied by the reaction force component is increased when the driving support control is prioritized, the first torque component input to the basic rotation angle component calculation unit is reduced, so that a small basic rotation angle component is reduced. It is calculated. That is, since the feeling of rigidity is enhanced by increasing the friction component, it is possible to preferably realize steering characteristics with high rigidity.

In the steering control device, the reaction force component calculation unit increases the reaction force component as the rotation angle increases, and the rate of change of the reaction force component with respect to the change in the rotation angle increases as the rotation angle increases. The reaction force component is calculated so that the absolute value becomes small, and it is preferable to calculate the reaction force component based on the difference between the operation support rotation angle component and the rotation angle.

According to the above configuration, when the driving support control is prioritized, the reaction force component is calculated so as to change significantly with respect to the change in the difference. As a result, the feeling of rigidity corresponding to the initial friction component is enhanced, so that steering characteristics with high rigidity can be suitably realized.

In the steering control device, when the driving support control is prioritized and the difference between the driving support rotation angle component and the rotation angle is equal to or greater than the threshold value, the basic rotation angle component is the threshold value. It is preferable that the calculation is made so that the ratio of the change in the steering reaction force to the change in the angle of rotation is larger than in the case where the value is less than.

According to the above configuration, when the difference between the driving support rotation angle component and the actual rotation angle becomes large, that is, when the steering is delayed due to the execution of the driving support control, the steering characteristics with higher rigidity are obtained. Since the basic rotation angle component is calculated so as to be, higher responsiveness can be realized for steering by driving support control.

According to the present invention, driving support control can be effectively executed while realizing excellent steering characteristics.

Schematic configuration diagram of the electric power steering device. The block diagram of the steering control device of 1st Embodiment. The graph which shows the steering torque, the basic assist component, and the assist gradient. The graph which shows the optimization of the phase compensation control based on the assist gradient. (A) is a graph showing the relationship between the pinion angle reaction force component at the time of cut-back steering, and (b) is a graph showing the relationship between the pinion angle and the reaction force component at the time of turn-back steering. A graph showing the relationship between the pinion angle and the reaction force component when sine steering is performed. The block diagram of the pinion angle command value calculation part of 1st Embodiment. (A) is a graph showing steering characteristics when sign steering is performed when driving support control is not prioritized, and (b) is a graph showing steering characteristics when sign steering is performed when driving support control is prioritized. The block diagram of the steering control device of the 2nd Embodiment. A graph showing the relationship between the difference between the pinion angle and the driving support pinion angle component and the reaction force gain (spring constant). The block diagram of the pinion angle command value calculation part of 2nd Embodiment.

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

The steering mechanism 4 is inserted into the steering shaft 11 to which the steering wheel 2 is fixed, the rack shaft 12 as a steering shaft that reciprocates in the axial direction according to the rotation of the steering shaft 11, and the rack shaft 12 that can reciprocate. It is provided with a substantially cylindrical rack housing 13. The steering shaft 11 is configured by connecting a column shaft 14, an intermediate shaft 15, and a pinion shaft 16 in this order from the steering wheel 2 side.

The rack shaft 12 and the pinion shaft 16 are arranged in the rack housing 13 at a predetermined crossing angle, and the rack teeth 12a formed on the rack shaft 12 and the pinion teeth 16a formed on the pinion shaft 16 are meshed with each other. As a result, the rack and pinion mechanism 17 is configured. Further, both ends of the rack shaft 12 are connected to a knuckle (not shown) to which the steering wheel 3 is assembled via a tie rod 18. Therefore, in EPS 1, the rotation of the steering shaft 11 accompanying the steering operation is converted into the axial movement of the rack shaft 12 by the rack and pinion mechanism 17, and this axial movement is transmitted to the knuckle via the tie rod 18. The steering angle of the steering wheel 3, that is, the traveling direction of the vehicle is changed.

The EPS actuator 5 includes a motor 21 as 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 reciprocating motion of the rack shaft 12. I have. Then, the EPS actuator 5 transmits the rotation of the motor 21 to the conversion mechanism 23 via the transmission mechanism 22, and the conversion mechanism 23 converts the rotation into the reciprocating motion of the rack shaft 12 to apply an assist force to the steering mechanism 4. .. The motor 21 of the present embodiment employs, for example, a three-phase brushless motor, the transmission mechanism 22 employs, for example, a belt mechanism composed of a pair of pulleys and a belt, and the conversion mechanism 23 employs, for example, a ball screw. The mechanism is adopted.

The steering control device 6 is connected to a vehicle speed sensor 31 that detects the vehicle speed V of the vehicle and a torque sensor 32 that detects the steering torque Th applied to the steering shaft 11 by the driver's steering. In the present embodiment, the torsion bar 24 is provided in the middle of the pinion shaft 16, and the torque sensor 32 detects the steering torque Th based on the twist of the torsion bar 24. Further, the steering control device 6 is connected to a rotation angle sensor 33 that detects the motor angle θm, which is the rotation angle of the motor 21. 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 the other direction (left in this embodiment). do.

Further, the steering control device 6 is communicably connected to the driving support control device 42 provided outside the steering control device 6 via the in-vehicle network 41. As the driving support control, the driving support control device 42 of the present embodiment executes, for example, lane keeping control that assists the driver's steering operation so as to maintain the traveling lane in which the vehicle is traveling and facilitate the driving. The driving support control device 42 calculates an ideal steering angle at which the vehicle can maintain driving in the lane based on the image data captured by the camera 43 when the lane keep control is executed, and this ideal steering angle is calculated. The driving support pinion angle component θp_adas * as the driving support rotation angle component according to the deviation between the steering angle and the actual steering angle of the steering wheel 3 is calculated. Further, the driving support control device 42 is connected to an operation switch 44 for executing driving support control provided near the driver's seat of the vehicle. The driving support control device 42 executes lane keep control as driving support control according to the on / off of the operation switch 44, and gives priority to the driving support pinion angle component θp_adas * and the driving support control for realizing the driving support. The indicated priority signal Spr is output to the steering control device 6.

Then, the steering control device 6 supplies the drive power to the motor 21 based on the signal indicating each state amount input from each of these sensors and the signal input from the driving support control device 42 via the in-vehicle network 41. This controls the operation of the EPS actuator 5. That is, the steering control device 6 executes assist control for applying an assist force to the steering mechanism 4 based on each signal.

As shown in FIG. 2, the steering control device 6 includes a microcomputer 51 that outputs a motor control signal, and a drive circuit 52 that supplies drive power to the motor 21 based on the motor control signal. The drive circuit 52 of the present embodiment employs a well-known PWM inverter having a plurality of switching elements (for example, FETs and the like). Each control block shown below is realized by a computer program executed by the microcomputer 51, and detects each state quantity in a predetermined sampling cycle (detection cycle). The microcomputer 51 executes each calculation process shown in each of the following control blocks at a predetermined calculation cycle to generate a motor control signal. Then, when the motor control signal is output to the drive circuit 52, the drive power corresponding to the motor control signal is supplied to the motor 21, and the operation of the EPS actuator 5 is controlled.

Specifically, the vehicle speed V, steering torque Th, motor angle θm, driving support pinion angle component θp_adas *, and priority signal Spr are input to the microcomputer 51. Further, each phase current value I of the motor 21 detected by the current sensor 54 provided on the connection line 53 between the drive circuit 52 and the motor coil of each phase is input to the microcomputer 51. In FIG. 2, for convenience of explanation, the connection line of each phase and the current sensor 54 of each phase are shown together as one. Then, the microcomputer 51 outputs a motor control signal 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 * as the torque command value, and a current command that calculates the current command values Id * and Iq * corresponding to the assist command value Ta *. It includes a value calculation unit 62 and a motor control signal generation unit 63 that generates a motor control signal based on current command values Id * and Iq *. Further, the microcomputer 51 includes a pinion angle calculation unit 64 that calculates (detects) the rotation angle (pinion angle θp) of the portion of the pinion shaft 16 on the steering wheel 3 side of the torsion bar 24 based on the motor angle θm. There is. In the pinion angle calculation unit 64, the motor 21 is mechanically connected to the steering shaft 11 via the transmission mechanism 22, the conversion mechanism 23, the rack shaft 12, and the rack and pinion mechanism 17, and the motor angle θm and the steering shaft The pinion angle θp is calculated from the motor angle θm by utilizing the fact that there is a correlation with the rotation angle of 11.

As will be described later, the assist command value calculation unit 61 executes the first assist component Ta1 * as the first torque component based on the steering torque Th and the rotation angle feedback control that causes the pinion angle θp to follow the pinion angle command value θp *. Based on the added value of the second assist component Ta2 * as the second torque component based on the above, the motor torque generated in the motor 21, that is, the assist command value Ta * corresponding to the target assist force is calculated.

The current command value calculation unit 62 calculates the current command values Id * and Iq *, which are the target values of the drive current of the motor 21, based on the assist command value Ta *. In the present embodiment, the current command value calculation unit 62 calculates the q-axis current command value Iq * on the q-axis in the d / q coordinate system, and outputs the q-axis current command value Iq * to the motor control signal generation unit 63. do. The d-axis current command value Id * on the d-axis is set to zero, and the current command value calculation unit 62 also outputs the d-axis current command value Id * to the motor control signal generation unit 63.

The motor control signal generation unit 63 generates a motor control signal by executing current feedback control that causes each phase current value I of the motor 21 to follow the current command values Id * and Iq *, and outputs the motor control signal to the drive circuit 52. .. Specifically, in addition to the d-axis current command value Id * and the q-axis current command value Iq *, each phase current value I and the motor angle θm are input to the motor control signal generation unit 63. The motor control signal generation unit 63 maps each phase current value I on the d / q coordinates based on the motor angle θm, so that the d-axis current value which is the actual current value of the motor 21 in the d / q coordinate system. And the q-axis current value is calculated. Then, the motor control signal generation unit 63 is based on each deviation so that the d-axis current value follows the d-axis current command value Id * and the q-axis current value follows the q-axis current command value Iq *. A motor control signal is generated by performing current feedback control. When this motor control signal is output to the drive circuit 52, drive power corresponding to the motor control signal is supplied to the motor 21, and the motor torque corresponding to the assist command value Ta * from the motor 21 (EPS actuator 5) is the assist force. Is given to the steering shaft 11.

Next, the calculation of the assist command value Ta * will be described in detail.
The assist command value calculation unit 61 has the basic assist component calculation unit 71 that calculates the basic assist component Tas *, which is the basic component of the assist command value Ta * (first assist component Ta1 *), and the phase that delays the phase of the steering torque Th. The compensation control unit 72 is provided. The basic assist component calculation unit 71 calculates the basic assist component Tas * based on the steering torque Th ′ and the vehicle speed V after the phase compensation by the phase compensation control unit 72.

As shown in FIG. 3, the basic assist component calculation unit 71 calculates the basic assist component Tas *, which has a larger absolute value as the absolute value of the steering torque Th'is larger and the vehicle speed V is smaller. In particular, in the relationship between the steering torque Th'and the basic assist component Tas *, the larger the steering torque Th', the greater the ratio of the change in the basic assist component Tas * to the change in the steering torque Th'. .. That is, the basic assist component calculation unit 71 calculates the basic assist component Tas * so that the larger the steering torque Th', the larger the assist gradient Rag represented by the slopes of the tangents L1 and L2.

As shown in FIG. 2, the basic assist component calculation unit 71 outputs the assist gradient Rag according to the steering torque Th ′ and the vehicle speed V to the phase compensation control unit 72. The phase compensation control unit 72 changes the characteristics (filter coefficient) of the phase compensation control based on the assist gradient Rag.

Specifically, as shown in FIG. 4, the phase compensation control unit 72 changes the phase compensation characteristics so as to reduce the gain according to the increase in the assist gradient Rag. By changing the characteristics of the phase compensation in this way, the generation of vibration is suppressed by the execution of the current feedback control by the motor control signal generation unit 63, and the responsiveness of the current control is improved while ensuring the stability of the control. Therefore, a good steering feeling is realized.

As shown in FIG. 2, the assist command value calculation unit 61 includes a reaction force component calculation unit 73 that calculates a reaction force component Tc * with respect to the steering torque Th (first assist component Ta1 *) transmitted to the steering shaft 11. ing. The reaction force component calculation unit 73 calculates the reaction force component Tc * based on the pinion angle θp, the vehicle speed V, and the driving support pinion angle component θp_adas *.

As shown in FIG. 5A, the reaction force component calculation unit 73 increases the reaction force component Tc * as the pinion angle θp increases during cut steering, and changes in the reaction force component Tc * with respect to the pinion angle θp. The reaction force component Tc * is calculated so that the absolute value of the rate becomes small. Further, as shown in FIG. 5B, the reaction force component calculation unit 73 calculates the reaction force component Tc * so that the reaction force component Tc * increases in proportion to the pinion angle θp at the time of turning back steering. ..

Then, the reaction force component calculation unit 73 changes the origin position of the pinion angle θp of the map shown in FIG. 5 based on the change in the steering direction and the steering state of whether the steering is turning or turning back. Calculate the reaction force component Tc *. As a result, as shown in FIG. 6, when the steering wheel 2 is sine-steered by repeatedly performing cut-in steering and turn-back steering at a constant frequency, the reaction force component calculation unit 73 responds to a change in the pinion angle θp. The reaction force component Tc * having a hysteresis characteristic is calculated. For details on the calculation of the reaction force component Tc * having such a hysteresis characteristic, refer to, for example, Patent Document 2 above.

As shown in FIG. 2, the assist command value calculation unit 61 includes a reaction force gain calculation unit 74 that calculates a reaction force gain G multiplied by a reaction force component Tc * based on the vehicle speed V. For example, the reaction force gain calculation unit 74 calculates the reaction force component Tc * such that the absolute value becomes smaller as the vehicle speed V increases, that is, the reaction force component Tc * becomes smaller. The reaction force gain G calculated by the reaction force gain calculation unit 74 is input to the multiplier 75. Then, the multiplier 75 multiplies the reaction force component Tc * by the reaction force gain G to calculate the final reaction force component Tc **.

The basic assist component Tas * and the final reaction force component Tc ** are input to the subtractor 76, respectively. Then, the subtractor 76 (assist command value calculation unit 61) subtracts the reaction force component Tc ** from the basic assist component Tas * to calculate the first assist component Ta1 *. As a result, the assist command value Ta * and the q-axis current command value Iq * are reduced by the amount of the reaction force component Tc ** subtracted from the basic assist component Tas *. That is, the assist force applied to the steering mechanism 4 is reduced by the amount of the reaction force component Tc **. As a result, the steering torque Th required for operating the steering wheel 2 increases, and a steering feeling corresponding to the reaction force component Tc ** is given to the driver as friction.

The assist command value calculation unit 61 calculates the pinion angle command value θp * based on the first assist component Ta1 *, the steering torque Th, the driving support pinion angle component θp_adas *, and the priority signal Spr. It has. The pinion angle command value θp * is calculated as a rotation angle command value of the rotation shaft that can be converted into the steering angle of the steering wheel 3.

As shown in FIG. 7, the first assist component Ta1 * and the steering torque Th are input to the adder 81 as the input torque calculation unit, respectively. Then, the adder 81 calculates the value obtained by adding the first assist component Ta1 * and the steering torque Th as the input torque Tp * transmitted to the pinion shaft 16. The pinion angle command value calculation unit 77 basically calculates the basic pinion angle component θp_base * as the basic rotation angle component based on the ideal model (input torque / rotation angle model) of the pinion shaft 16 that rotates by the input torque Tp *. The pinion angle component calculation unit 82 is provided. The ideal model is a model that utilizes the fact that the input torque Tp * is expressed by the following equation (1).

Tp * ＝ Jθp_base *'' ＋ Cθp_base *'＋ Kθp_base *… (1)
Here, the inertia coefficient J is a model of the inertia of the EPS, the viscosity coefficient C is a model of the friction of the EPS, and the spring coefficient K is the suspension of the vehicle on which the EPS is mounted. It is a model of specifications such as hole alignment. In this way, the input torque Tp * is the inertial term obtained by multiplying the second-order time derivative θp_base *'' (basic pinion angular acceleration component αp_base *) of the basic pinion angular component θp_base * by the inertial coefficient J, and the basic pinion angular component θp_base *. Table by adding the viscosity term obtained by multiplying the first-order time derivative value θp_base *'(basic pinion angular velocity component ωp_base *) by the viscosity coefficient C, and the spring term obtained by multiplying the basic pinion angular component θp_base * by the spring coefficient K. Will be done. That is, the inertial term is based on the value obtained by subtracting the spring component and the viscous component, which are the control outputs of the spring term and the viscosity term, from the input torque Tp *.

Specifically, the basic pinion angle component calculation unit 82 includes an inertial control calculation unit 83 corresponding to the inertial term, a viscosity control calculation unit 84 corresponding to the viscosity term, and a spring characteristic control calculation unit 85 corresponding to the spring term. The basic pinion angle component calculation unit 82 is provided.

The input torque Tp * is input to the subtractor 86 together with the viscous component Tvi * output from the viscous control calculation unit 84 and the spring component Tsp * output from the spring characteristic control calculation unit 85. The subtractor 86 outputs a value (Tp **) obtained by subtracting the viscous component Tvi * and the spring component Tsp * from the input torque Tp * to the inertial control calculation unit 83. The inertial control calculation unit 83 calculates the basic pinion angular acceleration component αp_base * based on the value Tp ** output from the subtractor 86.

The basic pinion angular acceleration component αp_base * is input to the integrator 87. The integrator 87 calculates the basic pinion angular velocity component ωp_base * by integrating the basic pinion angular acceleration component αp_base *. The basic pinion angular velocity component ωp_base * is input to the viscosity control calculation unit 84 and the integrator 88. The viscosity control calculation unit 84 calculates the viscosity component Tvi * based on the basic pinion angular velocity component ωp_base *, and outputs the viscosity component Tvi * to the subtractor 86 as described above. The integrator 88 calculates the basic pinion angular velocity component θp_base * by integrating the basic pinion angular velocity component ωp_base *. The basic pinion angle component θp_base * is input to the spring characteristic control calculation unit 85 and the adder 89. The spring characteristic control calculation unit 85 calculates the spring component Tsp * based on the basic pinion angle component θp_base *, and outputs the spring component Tsp * to the subtractor 86 as described above.

The basic pinion angle component θp_base * and the driving support pinion angle component θp_adas * output from the driving support control device 42 are input to the adder 89. The adder 89 (pinion angle command value calculation unit 77) calculates a value obtained by adding the basic pinion angle component θp_base * and the driving support pinion angle component θp_adas * as the pinion angle command value θp *. When the driving support control device 42 does not execute the driving support control, the driving support pinion angle component θp_adas * is zero, so that the pinion angle command value θp * is equal to the basic pinion angle component θp_base *.

As shown in FIG. 2, the assist command value calculation unit 61 executes a rotation angle feedback control that causes the pinion angle θp to follow the pinion angle command value θp * output from the pinion angle command value calculation unit 77 to perform a second assist component. A pinion angle F / B control unit 91 is provided as a second torque component calculation unit that calculates Ta2 *. The pinion angle F / B control unit 91 calculates the second assist component Ta2 * by performing a rotation angle feedback control calculation based on the deviation between the pinion angle command value θp * and the pinion angle θp.

The second assist component Ta2 * is input to the adder 92 together with the first assist component Ta1 *. Then, the adder 92 (assist command value calculation unit 61) adds the first and second assist components Ta1 * and Ta2 * to generate an assist command value Ta *, and outputs the assist command value Ta * to the current command value calculation unit 62. ..

By including the second assist component Ta2 * obtained through the rotation angle feedback control in the assist command value Ta *, the steering wheel 3 is steered according to the driver's intention, and the first assist component Ta1 is steered. By subtracting the reaction force component Tc * from *, a suitable steering feeling is created according to the steering operation, and excellent steering characteristics are realized.

Next, a configuration for effectively executing driving support control while realizing excellent steering characteristics will be described.
Here, since the basic pinion angle component θp_base * is calculated so as to realize excellent steering characteristics, it cannot always be said that high responsiveness can be realized. On the other hand, when the driving support control is executed, the motor 21 is driven based on the driving support pinion angle component θp_adas * regardless of the presence or absence of the steering operation by the driver, and is transmitted to the steering mechanism 4 (torque sensor). The steering torque Th (detected by 32) changes. That is, the pinion angle command value θp * includes the basic pinion angle component θp_base * for realizing excellent steering characteristics. As a result, the operation of the EPS actuator 5 is controlled so as to realize excellent steering characteristics, which may affect the followability of the actual pinion angle θp with respect to the driving support pinion angle component θp_adas *. ..

Based on this point, the microcomputer 51 of the present embodiment has a steering reaction force (or a pinion shaft torque transmitted to the pinion shaft 16) with respect to a change in the pinion angle θp when the driving support control is prioritized as compared with the case where the driving support control is not prioritized. The basic pinion angle component θp_base * is calculated so that the rate of change in Tp) increases. That is, the microcomputer 51 calculates the basic pinion angle component θp_base * so that the steering characteristic indicated by the relationship between the pinion angle θp and the steering reaction force shows high rigidity when the driving support control is prioritized.

Specifically, as shown in FIG. 2, a priority signal Spr is input to the reaction force gain calculation unit 74. The reaction force gain calculation unit 74 determines whether or not the driving support control is prioritized based on the priority signal Spr, and when the driving support control is prioritized, that is, the driving support control device 42 executes the driving support control. When the signal Spr is input, the reaction force gain G having a larger value than when the driving support control is not prioritized is calculated. Specifically, when the driving support control is not prioritized, "Gbase" is used as the reaction force gain G, and when the driving support control is prioritized, "Gadas" having a value larger than "Gbase" is used as the reaction force gain G. As a result, the final reaction force component Tc * output from the multiplier 75 is corrected to be larger than when the driving support control is not prioritized.

Further, when the driving support control is prioritized, the reaction force component calculation unit 73 inputs the driving support pinion angle component θp_adas * from the driving support control device 42. Then, the reaction force component calculation unit 73 calculates the reaction force component Tc * by referring to the map shown in FIG. 5 with the difference Δθp between the driving support pinion angle component θp_adas * and the pinion angle θp as the pinion angle θp. By calculating the reaction force component Tc * based on the difference Δθp in this way, the reaction force component calculation unit 73 calculates the reaction force component Tc * in the region where the absolute value of the pinion angle θp is small during cut steering. That is, the reaction force component Tc * calculated by the reaction force component calculation unit 73 changes significantly with respect to the change of the difference Δθp. When the driving support control is not prioritized, the driving support pinion angle component θp_adas * is not calculated (zero) by the driving support control device 42. Therefore, even when the driving support control is not prioritized, the reaction force component calculation unit 73 causes the driving support pinion angle component θp_adas. The reaction force component Tc * may be calculated based on the difference Δθp between * and the pinion angle θp.

Further, as shown in FIGS. 2 and 7, a priority signal Spr is input to the basic pinion angle component calculation unit 82 (spring characteristic control calculation unit 85). The basic pinion angle component calculation unit 82 determines whether or not the driving support control is prioritized based on the priority signal Spr, and when the driving support control is prioritized, the spring coefficient has a larger value than when the driving support control is not prioritized. Calculate the basic pinion angle component θp_base * using K. Specifically, when the driving support control is not prioritized, "Kbase" is used as the spring coefficient K, and when the driving support control is prioritized, "Kadas" having a value larger than "Kbase" is used as the spring coefficient K. The ideal model in which the spring coefficient K in the above equation (1) is "Kbase" corresponds to the normal ideal model, and the ideal model in which the spring coefficient K is "Kadas" corresponds to the driving support ideal model.

As a result, as shown in FIGS. 8A and 8B, when the steering wheel 2 is sine-steered at a constant frequency, the steering characteristic indicated by the relationship between the pinion angle θp and the steering reaction force is controlled by driving support. When the priority is given, the rigidity becomes higher than when the priority is not given.

As described above, according to the present embodiment, the following effects can be obtained.
(1) As shown in FIG. 8, since the steering characteristics show high rigidity when the driving support control is prioritized, high responsiveness to the steering by the driving support control can be realized. In other words, the fact that the ratio of the change in steering reaction force to the change in pinion angle θp increases as a steering characteristic means that even if a large steering torque Th is input, a small basic pinion angle component θp_base * is calculated. The ratio of the basic pinion angle component θp_base * to the second assist component Ta2 * becomes small. That is, since the amount of control for achieving excellent steering characteristics is small, it is possible to reduce the influence on the followability of the actual pinion angle θp with respect to the driving support pinion angle component θp_adas *. High responsiveness can be achieved. In this way, when the driver support control is prioritized, the driver controls the operation of the EPS actuator 5 based on the basic pinion angle component θp_base *, which is calculated so that the steering characteristics show higher rigidity than when the non-priority is given. The followability of steering by driving support control is prioritized over the steering feeling given to.

Further, by making the steering characteristic show high rigidity only when the driving support control is prioritized, excellent steering characteristics can be realized when the driving support control is not prioritized. In this way, when the driver support control is not prioritized, the operation of the EPS actuator 5 is controlled based on the basic pinion angle component θp_base *, which is calculated so that the steering characteristics are lower than those at the time of priority. The steering feeling given to the driver is prioritized over the followability.

(2) The basic pinion angle component θp_base * is calculated based on the driving support ideal model in which the spring coefficient K is large when the driving support control is prioritized. That is, since the feeling of rigidity is enhanced by calculating the basic pinion angle component θp_base * based on the ideal model having a large spring component, it is possible to preferably realize a steering characteristic with high rigidity.

(3) When the driving support control is prioritized, the value of the reaction force gain G multiplied by the reaction force component Tc * is increased, and the first assist component Ta1 * input to the basic pinion angle component calculation unit 82 is decreased to reduce the value. The basic pinion angle component θp_base * is calculated. That is, since the feeling of rigidity is enhanced by increasing the friction component, it is possible to preferably realize steering characteristics with high rigidity.

(4) Since the reaction force component calculation unit 73 calculates the reaction force component Tc * based on the difference Δθp between the pinion angle θp and the driving support pinion angle component θp_adas *, the reaction force component calculation unit 73 cuts and steers when the driving support control is prioritized. In this case, the reaction force component Tc * is calculated so as to change significantly with respect to the change of the difference Δθp. As a result, the feeling of rigidity corresponding to the initial friction component is enhanced, so that steering characteristics with high rigidity can be suitably realized.

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

The steering control device 6 of the present embodiment has a difference Δθp when the absolute value of the difference Δθp between the pinion angle θp and the driving support pinion angle component θp_adas * is equal to or greater than the threshold value Δθth when the driving support control is prioritized. The basic pinion angle component θp_base * is calculated so that the ratio of the change in the steering reaction force to the change in the pinion angle θp is larger than that in the case where the absolute value is less than the threshold value Δθth.

As shown in FIG. 9, in addition to the vehicle speed V and the priority signal Spr, the pinion angle θp and the driving support pinion angle component θp_adas * are input to the reaction force gain calculation unit 74. The reaction force gain calculation unit 74 calculates the difference Δθp between the pinion angle θp and the driving support pinion angle component θp_adas *, and the value of the reaction force gain G (Gadas) when the driving support control is prioritized is based on the difference Δθp. Calculate so that it becomes larger.

Specifically, as shown in FIG. 10, when the difference Δθp is less than the threshold value Δθth, the reaction force component calculation unit 73 sets the reaction force gain Gadas to a constant value larger than the reaction force gain Gbase, and the difference Δθp is When the threshold value is Δθth or more, the value of the reaction force gain Gadas is increased at a constant rate as the difference Δθp increases. Then, after the reaction force gain Gadas reaches the upper limit value Glim, the reaction force gain Gadas is maintained at the upper limit value Glim even if the absolute value of the difference Δθp becomes larger than that.

Further, as shown in FIG. 11, in addition to the basic pinion angle component θp_base * and the priority signal Spr, the pinion angle θp and the driving support pinion angle component θp_adas * are input to the spring characteristic control calculation unit 85. The spring characteristic control calculation unit 85 calculates the difference Δθp between the pinion angle θp and the driving support pinion angle component θp_adas *, and the value of the spring coefficient K (Kadas) when the driving support control is prioritized is larger based on the difference Δθp. Change to be. Since the spring characteristic control calculation unit 85 changes the value of the spring coefficient K in the same tendency as the calculation of the reaction force gain G by the reaction force component calculation unit 73, the vertical axis and the horizontal axis of the graph of FIG. 10 are respectively. The reference numerals are given in parentheses, and detailed description thereof will be omitted.

Next, the effect of this embodiment will be described. In this embodiment, the following effects can be obtained in addition to the effects of (1) to (4) of the first embodiment.
(5) When the difference Δθp becomes larger than the threshold value Δθth, that is, when the steering is delayed due to the execution of the driving support control, the value of the reaction force gain G and the spring coefficient K according to the magnitude of the difference Δθp. By increasing the value of, the basic pinion angle component θp_base * is calculated so that the steering characteristics have even higher rigidity. As a result, higher responsiveness to steering by driving support control can be realized.

In addition, each of the above-described embodiments can also be implemented in the following embodiments in which they are appropriately modified.
-In the second embodiment, the increasing tendency of the value of the reaction force gain G and the increasing tendency of the value of the spring coefficient K according to the difference between the driving support pinion angle component θp_adas * and the pinion angle θp may be different. ..

-In the second embodiment, when the absolute value of the difference Δθp between the driving support pinion angle component θp_adas * and the pinion angle θp is equal to or greater than the threshold value Δθth, both the value of the reaction force gain G and the value of the spring coefficient K are both. Is increased according to the difference Δθp, but the present invention is not limited to this, and only one of them may be increased according to the difference Δθp.

-In each of the above embodiments, the reaction force component calculation unit 73 calculates the reaction force component Tc * based on the difference Δθp between the pinion angle θp and the driving support pinion angle component θp_adas *, but the pinion is not limited to this. The reaction force component Tc * may be calculated based only on the angle θp.

-In each of the above embodiments, the reaction force component Tc * may be calculated so that the reaction force component calculation unit 73 does not have a hysteresis characteristic. Further, the calculation may be performed so that the characteristics of the reaction force component Tc * with respect to the pinion angle θp (difference Δθp) are the same during the cut-in steering and the turn-back steering.

-In each of the above embodiments, the basic pinion angle component calculation unit 82 calculates the basic pinion angle component θp_base * using an ideal model, but the present invention is not limited to this, and for example, the basic pinion angle component θp_base * is calculated by map calculation. You may.

-In each of the above embodiments, the reaction force gain G is increased and the spring coefficient K is increased when the driving support control is prioritized, but the present invention is not limited to this, and for example, only one of the reaction force gain G and the spring coefficient K is used. It may be increased. Further, if the basic pinion angle component θp_base * is calculated so that the ratio of the change in the steering reaction force to the change in the pinion angle θp becomes large, parameters other than the reaction force gain G and the spring coefficient K may be changed.

-In each of the above embodiments, the pinion angle θp is used as the rotation angle of the rotation shaft that can be converted into the steering angle of the steering wheel 3, but other angles such as the steering angle of the steering wheel 2 may be used.

-In the above embodiment, the inertia coefficient J, the viscosity coefficient C, and the spring coefficient K may be changed according to the vehicle speed V.
-In each of the above embodiments, the lane keep assist control is executed as the driving support control, but the present invention is not limited to this, and the parking assist control that assists the driver's steering when parking such as entering the garage or the automatic steering is performed. The automatic steering control to be performed may be executed.

-In each of the above embodiments, whether or not the driving support control is prioritized is switched by the operation input to the operation switch 44, but the present invention is not limited to this, and the driving support control device 42, for example, depends on the traveling condition of the vehicle. It may be determined whether or not to give priority to the driving support control, and the priority signal Spr may be output to the steering control device 6 according to the determination result.

-In each of the above embodiments, an EPS actuator 5 that applies an assist force to the steering mechanism 4 by converting the rotation of the motor 21 into a reciprocating motion of the rack shaft 12 by the conversion mechanism 23 is adopted, but the present invention is not limited to this. For example, one that applies an assist force to the column shaft 14 or the like via a reduction mechanism such as a worm and wheel may be adopted.

-In each of the above embodiments, EPS1 is adopted as the steering device to be controlled, but the present invention is not limited to this, and for example, a steer-by-wire (SBW) type steering device may be adopted.

1 ... EPS (electric power steering device, steering device), 3 ... steering wheel, 4 ... steering mechanism, 5 ... EPS actuator (actor), 6 ... steering control device, 11 ... steering shaft, 12 ... rack shaft (steering shaft) ), 16 ... Pinion shaft, 21 ... Motor, 24 ... Torque bar, 42 ... Driving support control device, 44 ... Operation switch, 51 ... Microcomputer, 52 ... Drive circuit, 61 ... Assist command value calculation unit, 62 ... Current command value Calculation unit, 63 ... Motor control signal generation unit, 64 ... Pinion angle calculation unit, 71 ... Basic assist component calculation unit, 72 ... Phase compensation control unit, 73 ... Reaction force component calculation unit, 74 ... Reaction force gain calculation unit, 78 ... Pinion angle command value calculation unit (rotation angle command value calculation unit), 81 ... adder (input torque calculation unit), 82 ... basic pinion angle component calculation unit (basic rotation angle component calculation unit), 83 ... inertial control calculation unit , 84 ... Viscous control calculation unit, 85 ... Spring characteristic control calculation unit, 91 ... Pinion angle F / B control unit (second torque component calculation unit), C ... Viscous coefficient, G ... Reaction force gain, Glim ... Upper limit value, J ... inertial coefficient, K ... spring coefficient, V ... vehicle speed, θm ... motor angle, Spr ... priority signal, Th ... steering torque, Ta * ... assist command value (torque command value), Tc *, Tc ** ... reaction force Component, Tp * ... Input torque, Ta1 * ... 1st assist component (1st torque component), Ta2 * ... 2nd assist component (2nd torque component), Tas * ... Basic assist component, Tsp * ... Spring component, Tvi *… Viscous component, Δθth… Threshold, θp… Pinion angle, Δθp… Difference, θp *… Pinion angle command value, θp_adas *… Driving support pinion angle component (driving support rotation angle component), θp_base *… Basic pinion angle component ( Basic rotation angle component).

Claims (5)

The control target is a steering device to which a motor torque that reciprocates the steering shaft of the steering mechanism is applied by an actuator that uses a motor as a drive source.
A first torque component calculation unit that calculates a first torque component based on the steering torque transmitted to the steering mechanism, and
A basic rotation angle component calculation unit that calculates the basic rotation angle component of the rotation shaft that can be converted into the steering angle of the steering wheel based on the steering torque and the first torque component.
A rotation angle command value that calculates a target rotation angle command value of the rotation angle of the rotation axis based on the basic rotation angle component and the operation support rotation angle component input from an externally provided operation support control device. The calculation unit and
It is provided with a second torque component calculation unit that executes rotation angle feedback control based on the rotation angle command value and calculates a second torque component.
A steering control device that controls the operation of the actuator based on a torque command value based on the value obtained by adding the second torque component to the first torque component.
Preferentially when the driving assist control by pre Symbol driving support control device, as compared to the non-priority time not to prioritize the driving support control, the basic rotation angle component, so that the rate of change of the steering reaction force with respect to a change in the rotation angle increases A steering control device that is calculated to show high rigidity with steering characteristics. In the steering control device according to claim 1,
It is provided with an input torque calculation unit that calculates an input torque transmitted to the rotating shaft based on the addition value of the steering torque and the first torque component.
The basic rotation angle component calculation unit calculates the basic rotation angle component based on an ideal model of the rotation angle with respect to the input torque.
The ideal model includes a normal ideal model used when the driving support control is not prioritized and a driving support ideal model used when the driving support control is prioritized.
In the normal ideal model and the operation support ideal model, the spring term based on the rotation angle, the viscosity term based on the rotation angular velocity, and the spring component and the viscosity component which are the control outputs of the spring term and the viscosity term are input torques. Represented including the inertial term based on the value subtracted from
A steering control device in which the spring coefficient constituting the spring term of the driving support ideal model is set to be larger than the spring coefficient constituting the spring term of the normal ideal model. In the steering control device according to claim 1 or 2.
A reaction force component calculation unit that calculates a reaction force component with respect to the first torque component based on the rotation angle, and a reaction force component calculation unit.
It is provided with a reaction force gain calculation unit that calculates the reaction force gain multiplied by the reaction force component.
The steering control device calculates the reaction force gain to a larger value when the driving support control is prioritized than when the driving support control is not prioritized. In the steering control device according to claim 3,
In the reaction force component calculation unit, the reaction force component increases as the rotation angle increases, and the absolute value of the rate of change of the reaction force component with respect to the change in the rotation angle decreases as the rotation angle increases. A steering control device that calculates the reaction force component and calculates the reaction force component based on the difference between the driving support rotation angle component and the rotation angle. In the steering control device according to any one of claims 1 to 4.
When the difference between the driving support rotation angle component and the rotation angle is equal to or more than the threshold value when the driving support control is prioritized, the basic rotation angle component is compared with the case where the difference is less than the threshold value. A steering control device calculated so that the ratio of a change in steering reaction force to a change in the angle of rotation becomes larger.

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