JP2020011585A - Steering control device - Google Patents

Abstract

To provide a steering control device that can prevent steering feeling from deteriorating when a failure occurs in a pump.SOLUTION: A microcomputer 61 of a steering control device 1 includes a torque command value calculation unit 71 configured to calculate a torque command value T* and controls a motor 41 so that motor torque output from the motor 41 becomes the torque command value T*. Further, the microcomputer 61 includes a failure determination unit 81 configured to determine a failure of a pump on the basis of a steering torque Th and a discharge pressure Pd of the pump. In addition, when a failure occurs in the pump, the torque command value calculation unit 71 calculates the torque command value T* so that the motor torque to rotate a steering shaft in a direction to assist steering operation increases compared to a case where no failure occurs.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a steering control device.

  2. Description of the Related Art Conventionally, as a steering device for a vehicle, a hydraulic actuator that applies an assisting force to assist a steering operation by a hydraulic pressure of hydraulic oil discharged from a pump, and an electric actuator that applies a motor torque to rotate a steering shaft connected to a steering wheel. There is one provided with an actuator (for example, Patent Document 1).

JP 2005-254843A

  By the way, when an abnormality occurs in the pump, a failure in boosting the discharge pressure of the pump may not occur sufficiently. As a result, the assist force applied by the hydraulic actuator in accordance with the steering operation is reduced, and there is a possibility that the steering feeling is reduced.

  An object of the present invention is to provide a steering control device capable of suppressing a decrease in steering feeling when an abnormality occurs in a pump.

  A steering control device that solves the above-mentioned problem has a pump and a hydraulic cylinder that is operated by hydraulic pressure of hydraulic oil discharged from the pump, and a steering mechanism is operated by a steering mechanism according to rotation of a steering shaft to which a steering wheel is connected. A torque command value for calculating a torque command value, with a steering device having a hydraulic actuator for providing an assisting force for assisting the motor and an electric actuator for providing a motor torque for rotating the steering shaft having a motor as a control target. A calculating unit for controlling the motor so that the motor torque output from the motor becomes the torque command value, wherein a steering torque input to the steering wheel and a discharge pressure of the pump or the Determining an abnormality of the pump based on a value indicating a steering amount of the steering mechanism. An abnormality determining unit, wherein the torque command value calculating unit is configured to, when an abnormality occurs in the pump, increase a motor torque for rotating the steering shaft in a direction to assist a steering operation more than when no abnormality occurs. The torque command value is calculated so that is increased.

  According to the above configuration, when an abnormality occurs in the pump, in addition to the rotation of the steering shaft by the steering operation (steering torque), the motor torque for rotating the steering shaft in a direction to assist the steering operation is increased. As the command value increases, the steering shaft rotates more. As a result, the assist force applied from the hydraulic actuator to the steering mechanism increases, and a decrease in steering feeling can be suppressed.

  According to the present invention, it is possible to suppress a decrease in steering feeling when an abnormality occurs in the pump.

The schematic block diagram of a steering device. FIG. 2 is a block diagram of the steering control device according to the first embodiment. 4 is a graph showing a relationship between a steering torque and a discharge pressure of a pump. FIG. 6 is a block diagram of a microcomputer according to a second embodiment.

(1st Embodiment)
Hereinafter, a first embodiment of a steering control device will be described with reference to the drawings.
As shown in FIG. 1, a steering device 2 to be controlled by a steering control device 1 includes a steering mechanism 5 that turns a steered wheel 4 based on an operation of a steering wheel 3 by a driver, and a steering operation performed by the steering mechanism 5. A hydraulic actuator 6 for providing an assisting force for assisting, and an electric actuator 7 for applying a motor torque to the steering mechanism 5 are provided.

  The steering mechanism 5 includes a steering shaft 11 to which the steering wheel 3 is fixed, and a rack shaft 12 that reciprocates in the axial direction according to the rotation of the steering shaft 11. 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 3 side.

  The rack shaft 12 and the pinion shaft 16 are arranged 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. The pinion mechanism 17 is configured. A tie rod 18 is connected to both ends of the rack shaft 12, and a tip of the tie rod 18 is connected to a knuckle (not shown) to which the steered wheels 4 are attached. Therefore, in the steering device 2, 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. Accordingly, the steered angle of the steered wheels 4, that is, the traveling direction of the vehicle is changed.

  The hydraulic actuator 6 controls a pump 21 serving as a hydraulic pressure supply source, a reservoir tank 22 storing hydraulic oil, a hydraulic cylinder 23 for providing an assist force based on hydraulic pressure, and a supply / discharge of hydraulic oil to / from the hydraulic cylinder 23. The control valve 24 includes a control valve 24 to be controlled, and oil passages L1 to L5 that connect the pump 21, the reservoir tank 22, the hydraulic cylinder 23, and the control valve 24 to each other. Note that an engine-driven pump driven by rotation of a crankshaft of an internal combustion engine (engine) 31 is employed as the pump 21.

  The hydraulic cylinder 23 includes a cylindrical cylinder tube 32 through which the rack shaft 12 is inserted so as to be able to reciprocate, and a piston 35 that partitions the inside of the cylinder tube 32 into a first hydraulic chamber 33 and a second hydraulic chamber 34. I have. The piston 35 is fixed to the rack shaft 12 so as to be axially movable integrally with the rack shaft 12.

  The control valve 24 is configured as a known rotary valve that controls the supply and discharge of hydraulic oil to the first and second hydraulic chambers 33 and 34 of the hydraulic cylinder 23 in conjunction with the steering operation. Specifically, the control valve 24 is provided with a supply port 36, a discharge port 37, and first and second supply / discharge ports 38 and 39. The supply port 36 is connected to the pump 21 via a supply oil passage L1, and the discharge port 37 is connected to the reservoir tank 22 via a discharge oil passage L2. The first supply / discharge port 38 is connected to the first hydraulic chamber 33 via a first supply / discharge oil passage L3, and the second supply / discharge port 39 is connected to the second hydraulic chamber 34 via a second supply / discharge oil passage L4. It is connected to the. Note that the pump 21 and the reservoir tank 22 are connected to each other via a suction oil passage L5.

  The electric actuator 7 includes a motor 41 as a drive source, and a speed reduction mechanism 42 such as a worm and wheel connected to the motor 41 and connected to the column shaft 14. Then, the electric actuator 7 transmits the motor torque output from the motor 41 to the column shaft 14 (the steering shaft 11) by decelerating the motor torque by the speed reduction mechanism 42. Note that a three-phase brushless motor is employed as the motor 41 of the present embodiment.

  In the steering device 2 configured as described above, the operating oil sent from the pump 21 is supplied to the control valve 24 via the supply oil passage L1. The hydraulic oil supplied to the control valve 24 is supplied to one of the first and second oil supply / discharge passages L3 and L4 in response to rotation of the steering shaft 11 by a driver's steering operation. It is supplied to one of the second hydraulic chambers 33 and 34. At this time, hydraulic oil is discharged from the other of the first and second hydraulic chambers 33, 34, and the hydraulic oil is supplied to the other of the first and second supply / discharge oil passages L3, L4, the control valve 24, and the discharge oil passage L2. It is discharged to the reservoir tank 22 through the reservoir tank 22. As a result, a hydraulic pressure difference is generated between the first hydraulic chamber 33 and the second hydraulic chamber 34, and an axial pressing force acting on the piston 35 and the rack shaft 12 assists the steering mechanism 5 on the basis of the hydraulic pressure difference. This is applied as a force to assist the steering operation. In the steering device 2, an axial pressing force is similarly generated in the hydraulic cylinder 23 in accordance with the rotation of the steering shaft 11 by the motor torque applied from the electric actuator 7, and the rack shaft 12 is rotated by the pressing force. By moving in the direction, the traveling direction of the vehicle can be changed. The pressing force generated by the hydraulic cylinder 23 increases as the amount of rotation of the steering shaft 11 from the neutral position increases.

Next, the electrical configuration of the present embodiment will be described.
The steering control device 1 is connected to the electric actuator 7 (motor 41) and controls the operation thereof. The steering control device 1 includes a central processing unit (CPU) and a memory (not shown), and various controls are executed by the CPU executing a program stored in the memory at each predetermined calculation cycle.

  A vehicle speed sensor 51 for detecting the vehicle speed V of the vehicle and a torque sensor 52 for detecting a steering torque Th applied to the steering shaft 11 are connected to the steering control device 1. The torque sensor 52 is provided closer to the steering wheel 3 than the column shaft 14 is connected to the electric actuator 7 (deceleration mechanism 42), and detects the steering torque Th based on the torsion of the torsion bar 53. The steering control device 1 is connected to a rotation angle sensor 54 that detects the rotation angle θm of the motor 41 as a relative angle within a range of 360 °. The steering torque Th and the rotation angle θm are detected as positive values when steering in one direction (right in the present embodiment) and negative values when steering in the other direction (left in the present embodiment). I do. Further, the steering control device 1 is connected with a pressure sensor 55 for detecting the discharge pressure Pd of the pump 21 and a notification unit 56 such as a warning light or a speaker for notifying any abnormality or the like. The upper-level ECU (not shown) controls the pressure sensor 55 so that the internal combustion engine 31 does not stop due to an increase in the discharge pressure Pd of the pump 21 when, for example, a steering operation is performed during idling of the vehicle. Used to control operation. That is, the pressure sensor 55 is a sensor used for performing so-called idle-up control.

  Further, the steering control device 1 is connected to a driving support control device 57 provided outside the steering control device 1. The driving support control device 57 of the present embodiment executes, as the driving support control, for example, lane departure prevention support control that supports the driver's steering operation so that the vehicle can easily travel while maintaining the traveling lane. . The driving support control device 57 calculates an ideal turning angle at which the vehicle can keep traveling in the lane based on the image data captured by the camera 58 when the lane departure prevention support control is executed. A driving support command value Tad * is calculated in accordance with the deviation between the actual turning angle of the steered wheels 4 and the actual turning angle. The driving support command value Tad * of the present embodiment is a component indicating the target value of the motor torque output by the motor 41. The driving support control device 57 is connected to an operation switch 59 for performing driving support control provided near the driver's seat or the like of the vehicle. Execute the support control. Then, the driving support control device 57 outputs the driving support command value Tad * to the steering control device 1 when the driving support control is executed.

  The steering control device 1 supplies drive power to the motor 41 based on a signal indicating each state quantity input from each of these sensors and a signal input from the driving support control device 57, thereby operating the electric actuator 7 Control.

Next, the configuration of the steering control device 1 will be described.
As shown in FIG. 2, the steering control device 1 includes a microcomputer 61 that outputs a control signal, and a drive circuit 62 that supplies drive power to the motor 41 based on the control signal. The drive circuit 62 of the present embodiment employs a well-known PWM inverter having a plurality of switching elements (for example, FETs). The control signal output from the microcomputer 61 defines the on / off state of each switching element. Thereby, each switching element is turned on / off in response to the control signal, and the energization pattern for each phase of the motor coil is switched, so that three-phase drive power is output to the motor 41.

  The microcomputer 61 receives the vehicle speed V, the steering torque Th, the rotation angle θm, and the driving support command value Tad *. Further, the microcomputer 61 receives respective phase current values Iu, Iv, Iw of the motor 41 detected by a current sensor 64 provided on a connection line 63 between the drive circuit 62 and the motor coil of each phase. . In FIG. 2, the connection line 63 of each phase and the current sensor 64 of each phase are collectively shown for convenience of explanation. Then, the microcomputer 61 outputs a control signal based on each of these state quantities.

  More specifically, the microcomputer 61 includes a torque command value calculator 71 that calculates a torque command value T * that is a target value of the motor torque output by the motor 41, and current command values Id * and Iq corresponding to the torque command value T *. A current command value calculation unit 72 for calculating * and a control signal output unit 73 for outputting a control signal based on the current command values Id * and Iq * are provided. The current command values Id * and Iq * are target values of the current to be supplied to the motor 41, and indicate the current command values on the d-axis and the q-axis in the d / q coordinate system, respectively.

  More specifically, the torque command value calculator 71 includes a basic command value calculator 75 that calculates a basic command value Tb *, which is a basic component of the torque command value T *. The basic command value calculation unit 75 receives the steering torque Th, the vehicle speed V, and a determination signal S output from an abnormality determination unit 81 described later. Then, when no abnormality occurs in the pump 21, the basic command value calculation unit 75 does not affect the driver's steering operation due to the internal friction of the electric actuator 7 itself based on the steering torque Th. The basic command value Tb * for operating the motor 41 is calculated as described above. The basic command value Tb * calculated in this way is output to the adder 76. The driving support command value Tad * is input to the adder 76 in addition to the basic command value Tb *. Then, the torque command value calculator 71 calculates the torque command value T * by adding the driving support command value Tad * to the basic command value Tb * in the adder 76. That is, when no abnormality has occurred in the pump 21, the torque command value calculation unit 71 according to the present embodiment sets the component that assists the steering operation to substantially zero, and sets the torque command value T for executing the driving support control. * Is calculated.

  The torque command value T * is input to the current command value calculation unit 72. The current command value calculation unit 72 calculates a q-axis current command value Iq * corresponding to the torque command value T * and outputs the same to the control signal output unit 73. In this embodiment, the d-axis current command value Id * is basically fixed to zero.

  The control signal output unit 73 performs current feedback control in the d / q coordinate system based on the current command values Id *, Iq *, the phase current values Iu, Iv, Iw, and the rotation angle θm of the motor 41. , Generate a control signal. More specifically, the control signal output unit 73 maps the phase current values Iu, Iv, Iw on the d / q coordinates based on the rotation angle θm, and thereby outputs the actual current of the motor 41 in the d / q coordinate system. A d-axis current value and a q-axis current value are calculated. Then, the control signal output unit 73 performs current feedback control 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 *. Thus, a control signal is generated. When this control signal is output to the drive circuit 62, drive power according to the control signal is supplied to the motor 41. Thus, the drive of the motor 41 is controlled such that the motor torque output by the motor 41 follows the torque command value corresponding to the q-axis current command value Iq *.

  Here, for example, if an abnormality such as seizure occurs in the pump 21 and it becomes impossible to generate sufficient hydraulic pressure in the pump 21, even if the steering is performed in the same manner as before the occurrence of the abnormality in the pump 21, a sufficient assist force is obtained. The steering feeling is not provided from the actuator 6 to the steering mechanism 5, and the steering feeling is reduced. Based on this point, the steering control device 1 determines whether or not an abnormality has occurred in the pump 21. If an abnormality has occurred, the steering control device 1 assists the steering operation more than when no abnormality has occurred. By calculating the torque command value T * so that the motor torque for rotating the steering shaft 11 in the direction in which the steering shaft 11 rotates, the steering operation of the driver is assisted.

  More specifically, the microcomputer 61 includes an abnormality determining unit 81 that determines whether an abnormality has occurred in the pump 21. The steering torque Th and the discharge pressure Pd of the pump 21 are input to the abnormality determination unit 81. The abnormality determination unit 81 determines that an abnormality has occurred in the pump 21 when the discharge pressure Pd is less than the pressure threshold Pdth, even though the absolute value of the steering torque Th is equal to or greater than the first predetermined torque Tth1. The first predetermined torque Tth1 is a value indicating a torque when the driver performs steering with a large force, and is set in advance by an experiment or the like. The pressure threshold value Pdth is sufficiently smaller than the discharge pressure Pd that is generated if the pump 21 is not abnormal when the steering torque Th having the same magnitude as the first predetermined torque Tth1 is input. Etc. are set. When determining that an abnormality has occurred in the pump 21, the abnormality determination unit 81 outputs a determination signal S indicating the abnormality to the basic command value calculation unit 75 and the notification unit 56 (see FIG. 1). I do.

  When the determination signal S indicating that an abnormality has occurred in the pump 21 is input, the basic command value calculation unit 75 determines whether the steering shaft 11 is in the direction of assisting the steering operation based on the steering torque Th and the vehicle speed V. A basic command value Tb * for rotating the rotation is calculated. Specifically, the basic command value calculation unit 75 calculates the basic command value Tb * having a larger absolute value as the steering torque Th is larger and the vehicle speed V is lower, and having the same sign as the steering torque Th. . That is, the basic command value calculation unit 75 of the present embodiment is configured such that the basic command value Tb * is substantially zero when no abnormality occurs in the pump 21, whereas By calculating the basic command value Tb * based on the steering torque Th and the vehicle speed V, the motor torque for rotating the steering shaft 11 in a direction to assist the steering operation is increased. Note that, when the determination signal S indicating that an abnormality has occurred in the pump 21 is input, the notification unit 56 notifies that fact.

Next, steering when an abnormality occurs in the pump 21 will be described.
As shown in FIG. 3, when an abnormality occurs in the pump 21, as shown by a two-dot chain line, even if the absolute value of the steering torque Th increases, no abnormality occurs in the pump 21 shown by the one-dot chain line. In comparison with the case, the discharge pressure Pd of the pump 21 does not increase. In this regard, in the present embodiment, since the motor torque for assisting the steering operation from the electric actuator 7 increases as described above, the discharge pressure Pd increases as shown by the solid line in FIG. As a result, the steering can be performed without the driver inputting a very large steering torque Th, and a decrease in the steering feeling is suppressed. Since the discharge pressure does not increase as much as when the pump 21 does not have any abnormality, the steering torque Th required for turning increases, and in addition, the notification unit 56 supplies the pump 21 with the pump 21 as described above. Since the occurrence of the abnormality is notified, the driver can recognize the abnormality of the pump.

Next, the operation and effect of the present embodiment will be described.
(1) The torque command value calculation unit 71 determines that the motor torque for rotating the steering shaft 11 in the direction to assist the steering operation is higher when the pump 21 has an abnormality than when the abnormality has not occurred in the pump. The torque command value T * is calculated so as to increase. Thus, when an abnormality occurs in the pump 21, in addition to the rotation of the steering shaft 11 due to the steering operation (the steering torque Th), the steering shaft is increased by the torque command value T * so as to increase the motor torque. 11 rotates a lot. As a result, the assist force applied from the hydraulic actuator 6 to the steering mechanism 5 increases, and a decrease in steering feeling can be suppressed.

(2) Since the abnormality determination unit 81 determines the abnormality of the pump 21 based on the steering torque Th and the discharge pressure Pd, it is possible to easily determine whether the pump 21 has an abnormality.
(3) The abnormality determination unit 81 determines the abnormality of the pump 21 based on the discharge pressure Pd detected by the pressure sensor 55 used for performing the idle-up control, so that the configuration of the steering device 2 is complicated. Can be prevented.

  (4) The abnormality determination unit 81 outputs the determination signal S to the notification unit 56. When the determination signal S indicating that an abnormality has occurred in the pump 21 is input, the notification unit 56 notifies that fact. Therefore, the driver can easily recognize that an abnormality has occurred in the pump 21.

(2nd Embodiment)
Next, a second embodiment of the steering control device will be described with reference to the drawings. Note that the main difference between the present embodiment and the first embodiment is only the determination method by the abnormality determination unit 81. Therefore, for convenience of explanation, the same components are denoted by the same reference numerals as those in the first embodiment, and description thereof is omitted.

  As shown in FIG. 4, the microcomputer 61 of the present embodiment calculates the rotation angle of the steering shaft 11, which is the rotation axis that can be converted into the steering angle of the steered wheels 4, that is, the steering angle θs indicating the steering amount of the steering mechanism 5. A steering angle calculation unit 91 for calculating is provided. The rotation angle θm is input to the steering angle calculation unit 91. The steering angle calculation unit 91 integrates (counts) the rotation speed of the motor 41 with the steering angle θs in the state where the rack shaft 12 is in the neutral position where the vehicle goes straight, as the origin (zero degree). Based on the rotation angle θm and the rotation angle θm, the steering angle θs is calculated as an absolute angle including a range exceeding 360 °. The steering angle θs is a positive value when the rotation angle is in one direction from the neutral position, and is a negative value when the rotation angle is in the other direction, similarly to the rotation angle θm of the motor 41.

  The abnormality determining unit 81 receives the steering torque Th and the steering angle θs. The abnormality determination unit 81 determines that an abnormality has occurred in the pump 21 when the absolute value of the steering angle θs is less than the steering angle threshold value θth even though the absolute value of the steering torque Th is equal to or greater than the second predetermined torque Tth2. Is determined. The second predetermined torque Tth2 is a value indicating a torque when the driver performs steering with a large force, and may be the same as or different from the first predetermined torque Tth1, and is set in advance by an experiment or the like. ing. The steering angle threshold value θth is a value indicating an angle that is sufficiently smaller than the steering angle θs that occurs when a steering torque Th having a magnitude equal to the second predetermined torque Tth2 is input in a state where there is no abnormality in the pump 21. Yes, it is set in advance by experiments or the like. Then, similarly to the first embodiment, when the abnormality determination unit 81 determines that an abnormality has occurred in the pump 21, the abnormality determination unit 81 outputs a determination signal S indicating the abnormality to the basic command value calculation unit 75 and the notification. Output to the unit 56 (see FIG. 1).

Next, the operation and effect of the present embodiment will be described. Note that the present embodiment has the following effects in addition to the functions and effects of (1), (3), and (4) of the first embodiment.
(5) Since the abnormality determination unit 81 determines the abnormality of the pump 21 based on the steering torque Th and the steering angle θs, it is possible to easily determine whether the abnormality has occurred in the pump 21.

This embodiment can be implemented with the following modifications. The present embodiment and the following modifications can be implemented in combination with each other within a technically consistent range.
In the second embodiment, the abnormality determination unit 81 may determine abnormality of the pump 21 based on the steering torque Th and the steering angular velocity ωs obtained by differentiating the steering angle θs. As an example, the abnormality determination unit 81 determines that an abnormality has occurred in the pump 21 when the steering angular velocity ωs is less than the angular velocity threshold ωth, even though the absolute value of the steering torque Th is equal to or greater than the third predetermined torque Tth3. It is possible to determine. The third predetermined torque Tth3 is a value indicating a torque when the driver performs steering with a large force, and may be the same as or different from the second predetermined torque Tth2. Further, the angular velocity threshold value ωth is a value indicating an angular velocity sufficiently smaller than the steering angular velocity ωs generated when the steering torque Th having the same magnitude as the third predetermined torque Tth3 is input in a state where there is no abnormality in the pump 21. .

  In the first embodiment, the abnormality determination unit 81 may perform the abnormality determination of the second embodiment in combination. That is, the abnormality determination unit 81 generates an abnormality in the pump 21 when both the abnormality determination based on the relationship between the steering torque Th and the discharge pressure Pd and the abnormality determination based on the relationship between the steering torque Th and the steering angle θs are established. It may be determined that it has been done. Further, abnormality determination based on the relationship between the steering torque Th and the steering angular velocity ωs may be combined.

In each of the above embodiments, the notification unit 56 may not be provided, and the notification unit 56 may not notify that the pump 21 has failed.
In each of the above embodiments, the driving support command value Tad * may not be input from the driving support control device 57 to the steering control device 1.

  In each of the above embodiments, when no abnormality has occurred in the pump 21, the basic command value calculation unit 75 may calculate the basic command value Tb * based on the steering torque Th and the vehicle speed V. In this configuration, when an abnormality occurs in the pump 21, a basic command value Tb * having an absolute value larger than that when no abnormality occurs in the pump 21 is calculated based on the steering torque Th and the vehicle speed V. become.

  In the above embodiments, when an abnormality occurs in the pump 21, the basic command value calculation unit 75 calculates the basic command value Tb * based on the steering torque Th and the vehicle speed V. However, the present invention is not limited to this. The basic command value Tb * may be calculated based only on the steering torque Th without considering the vehicle speed V, or the basic command value Tb * may be calculated considering other parameters.

Next, technical ideas that can be grasped from the above embodiments and modifications will be additionally described below, together with their effects.
(A) The abnormality determination unit determines that an abnormality has occurred in the pump when the discharge pressure is less than a pressure threshold, even though the absolute value of the steering torque is equal to or greater than a first predetermined torque. Steering control device.

  (B) The abnormality determination unit determines that an abnormality has occurred in the pump when the steering angle of the steering wheel is less than a steering angle threshold value even though the absolute value of the steering torque is equal to or greater than a second predetermined torque. A steering control device that determines that the operation has been performed.

  (C) The abnormality determination unit determines that the pump has failed when the steering angular velocity of the steering wheel is less than the angular velocity threshold value, even though the absolute value of the steering torque is equal to or greater than a third predetermined torque. The steering control device that determines.

  According to each of the above configurations, it is possible to easily determine whether an abnormality has occurred in the pump.

  DESCRIPTION OF SYMBOLS 1 ... Steering control device, 2 ... Steering device, 3 ... Steering wheel, 4 ... Steering wheel, 5 ... Steering mechanism, 6 ... Hydraulic actuator, 7 ... Electric actuator, 11 ... Steering shaft, 12 ... Rack shaft, 21 ... Pump, 23 ... Hydraulic cylinder, 24 ... Control valve, 41 ... Motor, 56 ... Notification unit, 57 ... Drive support control unit, 61 ... Microcomputer, 71 ... Torque command value calculation unit, 81 ... Abnormality judgment unit, 91 ... Steering angle calculation unit , S: determination signal, Pd: discharge pressure, T *: torque command value, Tad *: driving support command value, Tb *: basic command value, Th: steering torque, Tth1: first predetermined torque, Tth2: second predetermined Torque, Tth3: third predetermined torque, θs: steering angle, ωs: steering angular velocity, θth: steering angle threshold, ωth: angular velocity threshold, Pdth: pressure threshold.

Claims (1)

A hydraulic actuator having a pump and a hydraulic cylinder operated by hydraulic pressure of hydraulic oil discharged from the pump, and applying an assist force to a steering mechanism to assist a steering operation in accordance with rotation of a steering shaft to which a steering wheel is connected. When,
A steering device having a motor and an electric actuator for applying a motor torque for rotating the steering shaft is to be controlled,
A steering control device that includes a torque command value calculation unit that calculates a torque command value, and controls the motor so that a motor torque output from the motor becomes the torque command value.
An abnormality determination unit that determines abnormality of the pump based on a steering torque input to the steering wheel and a value indicating a discharge pressure of the pump or a steering amount of the steering mechanism,
The torque command value calculating unit is configured such that, when an abnormality occurs in the pump, the motor torque for rotating the steering shaft in a direction to assist a steering operation becomes larger than when no abnormality occurs. A steering control device that calculates a torque command value.