Steering control device

Abstract

To provide a steering control device capable of appropriately steering a steering wheel according to a steering state of a steering wheel.SOLUTION: A steering control device includes: a first processing section (63E, 63F, 63G); a second processing section (63H); a third processing section (63J, 63K, 63 L); and a fourth processing section (63 N). The first processing section calculates a torque command value corresponding to a deviation between a target pinion angle and a pinion angle. The second processing section calculates a compensation value for compensating for the viscosity of a steering mechanism on the basis of a deviation between a target pinion angular velocity and a pinion angular velocity. The third processing section restricts each of variation ranges of the torque command value and the compensation value on the basis of limit values determined for each of the torque command value and the compensation value. The fourth processing section subtracts a compensation value after limit processing from a torque command value after limit processing and calculates a steering torque command value. The third processing section varies the limit value according to a traveling state of a vehicle.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a steering control device. [Background technology]

[0002] Conventionally, there exists an electric power steering device that assists steering wheel operation by applying motor torque as an assist force to a steering shaft. The control device of the electric power steering device calculates a current command value for the motor based on the steering torque detected by a torque sensor. The control device controls the power supply to the motor based on the current command value. As a result, the motor generates torque corresponding to the steering torque.

[0003] In recent years, there has been a so-called steer-by-wire steering device in which power transmission between the steering wheel and the steered wheels is separated. The steering device has a reaction motor that generates a steering reaction force applied to the steering shaft, and a steering motor that generates a steering force for turning the steered wheels. A control device for the steering device generates the steering reaction force by controlling the power supply to the reaction motor, and steers the steered wheels by controlling the power supply to the steering motor.

[0004] For example, the steering device of Patent Document 1 is capable of executing emergency avoidance assist control. The steering device control device controls a motor based on information provided by a higher-level control device. When there is a risk of the vehicle colliding with an obstacle present in the vehicle's traveling direction, the higher-level control device calculates a target steering angle for moving the vehicle in a direction away from the obstacle. The steering device control device executes feedback control so that the actual steering angle matches the target steering angle.

[0005] When executing emergency avoidance assist control, the steering device control device sets the value of the feedback gain to a value greater than the feedback gain during normal driving, for example. This is because emergency avoidance assist control requires higher responsiveness than control during normal driving. The feedback control is PID control, and includes proportional control, integral control, and differential control. The feedback gain includes a proportional gain, an integral gain, and a differential gain.

[0006] The steering device control device calculates the deviation between the target steering angle calculated by the higher-level control device and the actual steering angle. The control device calculates the steering angle of the steered wheels based on the rotation angle of the motor detected by the rotation angle sensor. The control device calculates a current command value for the motor by adding together a value obtained by multiplying the proportionally processed deviation by a proportional gain, a value obtained by multiplying the integrated deviation by an integral gain, and a value obtained by multiplying the differentiated deviation by a differential gain. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-82915 Summary of the Invention [Problem to be solved by the invention]

[0008] A steering device control device may be configured to perform various types of compensation control on a current command value in order to achieve a better steering feel. One example of compensation control is damping control. For example, the control device calculates a compensation value for compensating for the viscosity of the steering device based on the steering speed, and corrects the current command value using the calculated compensation value.

[0009] The steering device control device may be configured to set limit values ​​for limiting the range of change of each value calculated through the execution of proportional control, integral control, derivative control, and damping control. The limit values ​​include upper and lower limit values ​​for each value. If an excessive value exceeding the limit value is calculated through the execution of each control, the control device limits the calculated excessive value to an appropriate value equal to or less than the limit value.

[0010] However, depending on the limit values ​​for each value, the following concerns may arise. For example, when an emergency avoidance operation is performed via the steering wheel, the value calculated through the execution of proportional control or integral control and the compensation value calculated through the execution of damping control may cancel each other out. This may result in a concern that the steered wheels may not be steered appropriately. Therefore, it is necessary to steer the steered wheels appropriately depending on the steering state of the steering wheel. [Means for solving the problem]

[0011] A steering control device that can solve the above problem is a steering motor that generates a steering force for steering the steered wheels of a vehicle, the steering control device calculates a target angle of a rotating body that rotates in conjunction with the operation of the steered wheels in accordance with the steering state of the steering wheel, and calculates a steering torque command value for the steering motor by executing feedback control that causes an actual angle of the rotating body to follow the target angle. The steering control device has a first processing unit that calculates a torque command value in accordance with a deviation between the target angle and the actual angle, a second processing unit that calculates a compensation value for the torque command value based on the target angular velocity or the actual angular velocity of the rotating body, the compensation value acting in an opposite direction to the torque command value, a third processing unit that performs limiting processing to limit ranges of change of the torque command value and the compensation value based on limit values ​​set for each of the torque command value and the compensation value, and a fourth processing unit that calculates the turning torque command value using the torque command value after the limiting processing has been performed and the compensation value after the limiting processing has been performed. The third processing unit increases the limit values ​​set for the torque command value and the compensation value individually in accordance with the running state of the vehicle.

[0012] For example, if the limit value is set to a fixed value, the torque command value and the compensation value may be limited to the same value depending on the running state of the vehicle, which may result in the torque command value and the compensation value canceling each other out.

[0013] According to the above configuration, the limit values ​​set for the torque command value and the compensation value are increased individually in accordance with the vehicle's running state. By expanding the ranges of change for the torque command value and the compensation value in accordance with the vehicle's running state, it is possible to prevent the torque command value and the compensation value from being limited to the same value, and thus to prevent the torque command value and the compensation value from canceling each other out. Therefore, the steered wheels can be steered appropriately in accordance with the steering state of the steering wheel.

[0014] In the above-described steering control device, the third processing unit may increase the limit value when a value of a vehicle state variable that reflects a traveling state of the vehicle exceeds a determined threshold value.

[0015] According to this configuration, when the value of the vehicle state variable reflecting the vehicle's running state exceeds a predetermined threshold, the limit values ​​set for the torque command value and the compensation value are increased. By expanding the range of change of the torque command value and the range of change of the compensation value, the torque command value and the compensation value are prevented from being limited to the same value. This prevents the torque command value and the compensation value from canceling each other out. Therefore, the steered wheels can be appropriately steered according to the steering state of the steering wheel.

[0016] In the above-described steering control device, the third processing unit may be configured to increase the limit values ​​defined for the torque command value and the compensation value to the same value when the value of the vehicle state variable exceeds the threshold value.

[0017] According to this configuration, when the value of the vehicle state variable exceeds the threshold value, the limit values ​​set for the torque command value and the compensation value are increased to the same value. This expands the range of change for the torque command value and the compensation value. Since the torque command value and the compensation value are prevented from being limited to the same value, it is possible to prevent the torque command value and the compensation value from canceling each other out. Therefore, the steered wheels can be steered appropriately according to the steering state of the steering wheel.

[0018] In the above-described steering control device, the third processing unit may be configured to increase the limit values ​​defined for the torque command value and the compensation value to values ​​different from each other when the value of the vehicle state variable exceeds the threshold value.

[0019] According to this configuration, when the value of the vehicle state variable exceeds the threshold value, the limit values ​​set for the torque command value and the compensation value are increased to different values. This expands the ranges of change for the torque command value and the compensation value. Since the torque command value and the compensation value are prevented from being limited to the same value, it is possible to prevent the torque command value and the compensation value from canceling each other out. Therefore, the steered wheels can be appropriately steered according to the steering state of the steering wheel.

[0020] In the above-described steering control device, the limit value for the torque command value may be greater than the limit value for the compensation value. According to this configuration, when the value of the vehicle state variable exceeds the threshold value, the torque command value can be reflected more in the turning torque command value.

[0021] In the above-described steering control device, the third processing unit may be configured to increase the limit value as the value of the vehicle state variable increases when the value of the vehicle state variable exceeds the threshold value.

[0022] According to this configuration, the limit value can be increased appropriately in accordance with the value of the vehicle state variable. In the above-mentioned steering control device, the value of the vehicle state variable may be a value of vehicle speed detected by an on-board sensor, a value of yaw rate, a value of the ratio between the target angle and the actual angle, or a value of the ratio between the target angular velocity and the actual angular velocity. These values ​​reflect the running state of the vehicle.

[0023] In the above-described steering control device, the third processing unit may determine that there is a risk of an emergency avoidance operation being performed via the steering wheel when the value of the vehicle state variable exceeds the threshold value.

[0024] With this configuration, it is possible to determine whether or not an emergency avoidance maneuver is likely to be performed via the steering wheel by comparing the vehicle state variable with the threshold value. When an emergency avoidance maneuver is performed, it is required to appropriately steer the steered wheels in accordance with the steering state of the steering wheel.

[0025] In the above-described steering control device, the third processing unit may have a gradual change processing unit that, when changing the limit value, performs gradual change processing on the limit value to gradually change the limit value over time.

[0026] With this configuration, sudden changes in the limit value are suppressed, and therefore sudden changes in the torque command value and compensation value, and ultimately in the steering torque command value, are suppressed, thereby suppressing sudden changes in the steering force generated by the steering motor.

[0027] In the above-described turning control device, the torque command value may include a first torque command value that is proportional to the deviation calculated by performing a proportional operation on the deviation, and a second torque command value that is proportional to an integral value of the deviation calculated by performing an integral operation on the deviation. In this case, the third processing unit may limit a range of change of the sum of the first torque command value and the second torque command value based on the limit value set for the sum.

[0028] According to this configuration, the limit values ​​set for the sum of the first torque command value and the second torque command value and the compensation value are increased in accordance with the vehicle's running state. By expanding the range of change for the sum and the compensation value, the sum and the compensation value are prevented from being limited to the same value. This prevents the sum and the compensation value from canceling each other out. Therefore, the steered wheels can be steered appropriately in accordance with the steering state of the steering wheel.

[0029] In the above-described turning control device, the torque command value may include a first torque command value that is proportional to the deviation calculated by performing a proportional operation on the deviation, and a second torque command value that is proportional to an integral value of the deviation calculated by performing an integral operation on the deviation. In this case, the third processing unit may limit change ranges of the first torque command value and the second torque command value based on the limit values ​​determined for each of the first torque command value and the second torque command value.

[0030] According to this configuration, the limit values ​​set for each of the first torque command value, the second torque command value, and the compensation value are increased in accordance with the vehicle's running state. By expanding the range of change of the first torque command value, the range of change of the second torque command value, and the range of change of the compensation value, respectively, the first torque command value, the second torque command value, and the compensation value are prevented from being limited to the same value. This prevents the first torque command value and the compensation value from canceling each other out, or the second torque command value and the compensation value from canceling each other out. Therefore, the steered wheels can be appropriately steered in accordance with the steering state of the steering wheel. [Effects of the Invention]

[0031] According to the steering control device of the present invention, the steered wheels can be steered appropriately in accordance with the steering state of the steering wheel. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is a configuration diagram of a steering device in which a first embodiment of a steering control device is mounted. [Figure 2] 1 is a block diagram of a reaction force control device and a steering control device according to a first embodiment. [Figure 3] FIG. 2 is a block diagram of a pinion angle feedback control unit according to the first embodiment. [Figure 4] FIG. 2 is a block diagram of first to third guard processing units according to the first embodiment. [Figure 5] 10 is a graph showing a change over time in a torque command value according to a comparative example. [Figure 6] 5 is a graph showing a first example of a change over time in a torque command value according to the first embodiment. [Figure 7] 10 is a graph showing a second example of a change over time in a torque command value according to the first embodiment. [Figure 8] FIG. 10 is a block diagram of a pinion angle feedback control unit according to a second embodiment. [Figure 9] 10 is a graph showing a first map used by a setting unit according to the third embodiment. [Figure 10] 10 is a graph showing a second map used by a setting unit according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0033] A first embodiment of the steering control device will be described below. <Overall structure> As shown in FIG. 1, the control object of steering control device 1 is steer-by-wire steering device 2. Steering device 2 has steering mechanism 3 and steering mechanism 4. Steering mechanism 3 is a mechanical part that is steered by a driver via steering wheel 5. Steering mechanism 4 is a mechanical part that steers steerable wheels 6 of the vehicle in response to steering of steering wheel 5. Steering control device 1 includes reaction force control device 1A and steering control device 1B. The control object of reaction force control device 1A is steering mechanism 3. Reaction force control device 1A performs reaction force control. The control object of steering control device 1B is steering mechanism 4. Steering control device 1B performs steering control.

[0034] The steering mechanism 3 has a steering shaft 11, a reaction motor 12, and a reducer 13. The steering wheel 5 is connected to the steering shaft 11 so as to be rotatable integrally therewith. The reaction motor 12 is a source of a steering reaction force applied to the steering shaft 11. The steering reaction force is a force in the opposite direction to the steering direction of the steering wheel 5. The reaction motor 12 is, for example, a three-phase brushless motor. The reducer 13 decelerates the rotation of the reaction motor 12 and transmits the decelerated rotation to the steering shaft 11.

[0035] The steering mechanism 4 has a pinion shaft 21, a steered shaft 22, and a housing 23. The housing 23 rotatably supports the pinion shaft 21. The housing 23 also accommodates the steered shaft 22 so that it can reciprocate. The pinion shaft 21 is arranged to intersect with the steered shaft 22. Pinion teeth 21a of the pinion shaft 21 mesh with rack teeth 22a of the steered shaft 22. Tie rods 25 are connected to both ends of the steered shaft 22 via rack ends 24 made up of ball joints. The ends of the tie rods 25 are connected to knuckles (not shown) to which the steered wheels 6 are assembled.

[0036] The steering mechanism 4 comprises a steering motor 31, a transmission mechanism 32, and a conversion mechanism 33. The steering motor 31 is a source of the steering force applied to the steering shaft 22. The steering force is a force for steering the steered wheels 6. The steering motor 31 is, for example, a three-phase brushless motor. The transmission mechanism 32 is, for example, a belt transmission mechanism. The transmission mechanism 32 transmits the rotation of the steering motor 31 to the conversion mechanism 33. The conversion mechanism 33 is, for example, a ball screw mechanism. The conversion mechanism 33 converts the rotation transmitted via the transmission mechanism 32 into axial movement of the steering shaft 22.

[0037] The steered shaft 22 moves in the axial direction, and the steered angle θ of the steered wheels 6 wThe pinion teeth 21a of the pinion shaft 21 mesh with the rack teeth 22a of the steered shaft 22, and therefore rotate in conjunction with the movement of the steered shaft 22. The pinion shaft 21 is a rotating body that rotates in conjunction with the steering operation of the steered wheels 6.

[0038] The reaction force control device 1A controls the operation of the reaction force motor 12. The reaction force control device 1A has a processing circuit including any one of the following three components A1, A2, and A3. A1. One or more processors that operate according to a computer program, which is software. The processor includes a CPU (central processing unit) and memory.

[0039] A2. One or more dedicated hardware circuits, such as an application specific integrated circuit (ASIC), that perform at least some of the processing. The ASIC includes a CPU and memory.

[0040] A3. A hardware circuit that combines configurations A1 and A2. The memory is a computer-readable medium that stores a program that describes processes or instructions for the computer. In this embodiment, the computer is a CPU. The memory includes RAM (random access memory) and ROM (read only memory). The CPU executes the program stored in the memory at a predetermined calculation cycle to perform various controls.

[0041] The reaction force control device 1A receives detection results from sensors mounted on the vehicle, including a vehicle speed sensor 41, a torque sensor 42, and a rotation angle sensor 43. The vehicle speed sensor 41 detects the vehicle speed V. The vehicle speed V is a vehicle state quantity that reflects the traveling state of the vehicle. The torque sensor 42 is provided on the steering shaft 11. The torque sensor 42 is located on the steering wheel 5 side of the connecting portion of the steering shaft 11 with the reducer 13. The torque sensor 42 detects the steering torque Th applied to the steering shaft 11. The steering torque Th is calculated based on the amount of twist of a torsion bar 42a provided on the steering shaft 11. The rotation angle sensor 43 is provided on the reaction force motor 12. The rotation angle sensor 43 detects the rotation angle θ of the reaction force motor 12. a Detect.

[0042] Steering torque Th and rotation angle θ of reaction motor 12 a is, for example, a positive value when the steering wheel 5 is steered to the right, and is a negative value when the steering wheel 5 is steered to the left.

[0043] The reaction force control device 1A controls the operation of the reaction force motor 12 using the detection results of the vehicle speed sensor 41, the torque sensor 42, and the rotation angle sensor 43. The reaction force control device 1A controls the power supply to the reaction force motor 12 so that the reaction force motor 12 generates a steering reaction force corresponding to the steering torque Th.

[0044] The steering control device 1B controls the operation of the steering motor 31. Like the reaction force control device 1A, the steering control device 1B has a processing circuit including any one of the three components A1, A2, A3 described above.

[0045] The steering control device 1B takes in the detection results of sensors mounted on the vehicle. The sensors include a rotation angle sensor 44. The rotation angle sensor 44 is provided in the steering motor 31. The rotation angle sensor 44 detects a rotation angle θ of the steering motor 31. b The rotation angle θ of the steering motor 31 is detected. b is, for example, a positive value when the steering wheel 5 is steered to the right, and is a negative value when the steering wheel 5 is steered to the left.

[0046] The steering control device 1B uses the detection result of the rotation angle sensor 44 to control the operation of the steering motor 31. The steering control device 1B controls the supply of power to the steering motor 31 so that the steered wheels 6 are turned in accordance with the steering state of the steering wheel 5.

[0047] <Configuration of reaction force control device 1A> Next, the configuration of the reaction force control device 1A will be described. As shown in FIG. 2, the reaction force control device 1A includes a steering angle calculation unit 51, a reaction force torque command value calculation unit 52, and an energization control unit 53.

[0048] The steering angle calculation unit 51 calculates the rotation angle θ of the reaction force motor 12 detected through the rotation angle sensor 43. a Based on this, the steering angle θ of the steering wheel 5 s Calculate the following. The reaction torque command value calculation unit 52 calculates the reaction torque command value T based on the steering torque Th and the vehicle speed V. * Calculate the reaction torque command value T * is a target value of the steering reaction force to be generated by the reaction force motor 12. The steering reaction force is a torque in the direction opposite to the steering direction of the steering wheel 5. The larger the absolute value of the steering torque Th is and the slower the vehicle speed V is, the greater the reaction torque command value T * The absolute value of is larger.

[0049] The power supply control unit 53 determines the reaction torque command value T * Specifically, the power supply control unit 53 supplies the reaction force motor 12 with power according to the reaction force torque command value T * The current control unit 53 calculates a current command value for the reaction force motor 12 based on the current I generated in the power supply path through a current sensor 54 provided in the power supply path for the reaction force motor 12. a Detect the value of the current I a The value of is the value of the current supplied to the reaction motor 12. The current control unit 53 calculates the current command value and the current I a The deviation from the value of the reaction torque command value T is calculated, and the power supply to the reaction motor 12 is controlled so as to eliminate the deviation. *A torque corresponding to the

[0050] <Configuration of steering control device 1B> Next, the configuration of the steering control device 1B will be described. As shown in FIG. 2, the steering control device 1B has a pinion angle calculation unit 61, a target pinion angle calculation unit 62, a pinion angle feedback control unit 63, and an energization control unit 64.

[0051] The pinion angle calculation unit 61 calculates the rotation angle θ of the steering motor 31 detected through the rotation angle sensor 43. b Based on this, the pinion angle θ p Calculate the pinion angle θ p is the rotation angle of pinion shaft 21. Steering motor 31 and pinion shaft 21 are linked via transmission mechanism 32, conversion mechanism 33, and steering shaft 22. Therefore, the rotation angle θ of steering motor 31 b and pinion angle θ p By utilizing this correlation, the rotation angle θ of the steering motor 31 is b From pinion angle θ p The pinion shaft 21 is meshed with the steering shaft 22. Therefore, the pinion angle θ p There is also a correlation between the pinion angle θ and the amount of movement of the steering shaft 22. p is the steering angle θ of the steered wheels 6 w This is a value that reflects the

[0052] The target pinion angle calculation unit 62 calculates the steering angle θ calculated by the steering angle calculation unit 51. s Based on the target pinion angle θ p * The target pinion angle calculation unit 62 calculates the target pinion angle θ so as to realize a steering angle ratio set according to product specifications, etc. p * The steering angle ratio is calculated by the steering angle θ s steering angle θ w is the ratio of

[0053] The target pinion angle calculation unit 62 sets a steering angle ratio according to the vehicle running state, such as the vehicle speed V, and calculates the target pinion angle θ according to the set steering angle ratio. p * As the vehicle speed V decreases, the target pinion angle calculation unit 62 calculates the steering angle θ s steering angle θ w The target pinion angle θ p * As the vehicle speed V increases, the target pinion angle calculation unit 62 calculates the steering angle θ s steering angle θ w The target pinion angle θ p * The target pinion angle calculation unit 62 calculates the steering angle θ s The correction angle for the steering angle θ is calculated. s By adding to the target pinion angle θ according to the steering angle ratio p * Calculate the following.

[0054] Depending on the product specifications, the target pinion angle calculation unit 62 may calculate the target pinion angle θ so that the steering angle ratio becomes "1:1" regardless of the running state of the vehicle. p * The following may be calculated.

[0055] The pinion angle feedback control unit 63 receives the target pinion angle θ calculated by the target pinion angle calculation unit 62. p * , and the pinion angle θ calculated by the pinion angle calculation unit 61 p The pinion angle feedback control unit 63 receives the pinion angle θ p is the target pinion angle θ p * The pinion angle θ p Through the feedback control of the steering torque command value T p * Calculate the steering torque command value T p *is a command value for the torque generated by the steering motor 31, and is a target value of the steering force.

[0056] The power supply control unit 64 controls the steering torque command value T p * Specifically, the power supply control unit 64 supplies the steering motor 31 with electric power according to the steering torque command value T p * The current control unit 64 calculates a current command value for the steering motor 31 based on the current I generated in the power supply path through a current sensor 65 provided in the power supply path for the steering motor 31. b Detect the value of the current I b The value of is the value of the current supplied to the steering motor 31. The current control unit 64 calculates the current command value and the current I b The deviation from the value of the steering torque command value T is calculated and the power supply to the steering motor 31 is controlled so as to eliminate the deviation. p * A torque corresponding to the

[0057] <Configuration of pinion angle feedback control unit 63> Next, the configuration of the pinion angle feedback control unit 63 will be described. As shown in FIG. 3, the pinion angle feedback control unit 63 has a first subtractor 63A, a first differentiator 63B, a second differentiator 63C, and a second subtractor 63D.

[0058] The first subtractor 63A subtracts the target pinion angle θ calculated by the target pinion angle calculation unit 62. p * and the pinion angle θ calculated by the pinion angle calculation unit 61. p The first subtractor 63A takes in the angle deviation Δθ p Calculate the angle deviation Δθ p is the target pinion angle θ p * and pinion angle θ p This is the difference between

[0059] The first differentiator 63B is a differential amplifier for the target pinion angle θ calculated by the target pinion angle calculation unit 62. p * By differentiating the target pinion angular velocity ω p * Calculate the following. The second differentiator 63C is a pinion angle θ calculated by the pinion angle calculation unit 61. p By differentiating the pinion angular velocity ω p Calculate the following.

[0060] The second subtractor 63D subtracts the target pinion angular velocity ω calculated by the first differentiator 63B. p * The pinion angular velocity ω is calculated by the second differentiator 63C. p The second subtractor 63D takes in the angular velocity deviation Δω p Calculate the angular velocity deviation Δω p is the target pinion angular velocity ω p * and pinion angular velocity ω p This is the difference between

[0061] The pinion angle feedback control section 63 has a proportional control section 63E, an integral control section 63F, a differential control section 63G, and a damping control section 63H. The proportional control unit 63E subtracts the angle deviation Δθ calculated by the first subtractor 63A. p By performing a proportional operation on p The first torque command value T is proportional to p1 The proportional control section 63E calculates the angle deviation Δθ p is multiplied by the proportional gain to obtain the first torque command value T p1 The proportional gain is a constant that is tuned to achieve the desired control characteristics.

[0062] The integral control unit 63F subtracts the angle deviation Δθ calculated by the first subtractor 63A. p By performing an integral operation on p The second torque command value T is proportional to the integral value of p2The integral control unit 63F calculates the angle deviation Δθ p is integrated over time and multiplied by the integral gain to obtain the second torque command value T p2 The integral gain is a constant that is tuned to achieve the desired control characteristics.

[0063] The differential control unit 63G calculates the angular velocity deviation Δω calculated by the second subtractor 63D. p By performing a differential operation on p The third torque command value T is proportional to the differential value of p3 The differential control unit 63G calculates the angular velocity deviation Δω p is differentiated with respect to time, and the differentiated value is multiplied by the differential gain to obtain the third torque command value T p3 The differential gain is a constant that is tuned to achieve the desired control characteristics.

[0064] The damping control unit 63H calculates the pinion angular velocity ω p The pinion angular velocity ω is taken in. p Based on this, a fourth torque command value T p4 The fourth torque command value T p4 is the pinion angular velocity ω p The fourth torque command value T p4 is the first torque command value T p1 , the second torque command value T p2 , and the third torque command value T p3 The fourth torque command value T p4 is mainly the first torque command value T p1 is the compensation value for

[0065] Fourth torque command value T p4 is converted into the first torque command value T p1 , the second torque command value T p2, and the third torque command value T p3 or the first torque command value T p1 , the second torque command value T p2 , and the third torque command value T p3 Incidentally, the damping control unit 63H is a compensation value that acts in the opposite direction to the sum of the target pinion angular velocity ω p * Based on this, the fourth torque command value T p4 The following may be calculated.

[0066] The pinion angle feedback control unit 63 has a first adder 63I, a first guard processing unit 63J, a second guard processing unit 63K, and a third guard processing unit 63L. The first adder 63I calculates the first torque command value T p1 and the second torque command value T calculated by the integral control unit 63F. p2 The first adder 63I takes in the first torque command value T p1 and the second torque command value T p2 The fifth torque command value T p5 The fifth torque command value T p5 is the first torque command value T p1 and the second torque command value T p2 It is the sum of the above.

[0067] The first guard processing unit 63J calculates the fifth torque command value T p5 , and the vehicle speed V detected by the vehicle speed sensor 41. The first guard processing unit 63J calculates a fifth torque command value T p5 The limit value is calculated based on the fifth torque command value T p5 The first guard processing unit 63J determines the fifth torque command value T based on the upper and lower limits. p5 The first guard processing unit 63J performs a limiting process on the sixth torque command value T p6 Calculate the following.

[0068] The first guard processing unit 63J calculates the fifth torque command value T p5 The first guard processing unit 63J compares the fifth torque command value T p5 exceeds the upper limit, the fifth torque command value T p5 is limited to the upper limit value. The fifth torque command value T p5 is the sixth torque command value T p6 This becomes:

[0069] The first guard processing unit 63J calculates the fifth torque command value T p5 The first guard processing unit 63J compares the fifth torque command value T p5 If is lower than the lower limit, the fifth torque command value T p5 is limited to the lower limit value. The fifth torque command value T p5 is the sixth torque command value T p6 This becomes:

[0070] The fifth torque command value T p5 is within the range between the upper limit value and the lower limit value, the fifth torque command value T calculated by the first adder 63I p5 is the sixth torque command value T p6 This becomes:

[0071] The second guard processing unit 63K calculates the third torque command value T p3 , and the vehicle speed V detected by the vehicle speed sensor 41. The second guard processing unit 63K calculates a third torque command value T p3 The limit value is calculated based on the third torque command value T p3 The second guard processing unit 63K determines the third torque command value T based on the upper and lower limits. p3 The second guard processing unit 63K performs a limiting process on the seventh torque command value T p7 Calculate the following.

[0072] The third guard processing unit 63L calculates the fourth torque command value T p4 , and the vehicle speed V detected by the vehicle speed sensor 41. The third guard processing unit 63L calculates a fourth torque command value T p4 The limit value is calculated based on the fourth torque command value T p4 The third guard processing unit 63L determines the fourth torque command value T based on the upper and lower limits. p4 The third guard processing unit 63L performs a limiting process on the eighth torque command value T p8 Calculate the following.

[0073] The pinion angle feedback control unit 63 has a second adder 63M, a third subtractor 63N, and a fourth guard processing unit 63O. The second adder 63M calculates the sixth torque command value T p6 and the seventh torque command value T calculated by the second guard processing unit 63K. p7 The second adder 63M takes in the sixth torque command value T p6 and the seventh torque command value T p7 The ninth torque command value T p9 Calculate the following.

[0074] The third subtractor 63N subtracts the ninth torque command value T calculated by the second adder 63M. p9 and the eighth torque command value T calculated by the third guard processing unit 63L. p8 The third subtractor 63N takes in the ninth torque command value T p9 to the eighth torque command value T p8 The 10th torque command value T p10 Calculate the following.

[0075] The fourth guard processing unit 63O subtracts the tenth torque command value T p10 The fourth guard processing unit 63O takes in the tenth torque command value Tp10 The limit value is the tenth torque command value T p10 The fourth guard processing unit 63O determines a tenth torque command value T based on the upper and lower limits. p10 Through the execution of the limiting process, fourth guard processing section 63O limits the final steering torque command value T p * Calculate the following.

[0076] In addition, the target pinion angle θ p * corresponds to the target angle of the rotating body that rotates in conjunction with the movement of the steered wheels 6. p corresponds to the actual angle of the rotor. Target pinion angular velocity ω p * corresponds to the target angular velocity of the rotor. p corresponds to the actual angular velocity of the rotating body. Furthermore, proportional control section 63E, integral control section 63F, and differential control section 63G constitute a first processing section. Damping control section 63H constitutes a second processing section. First guard processing section 63J, second guard processing section 63K, and third guard processing section 63L constitute a third processing section. Third subtractor 63N constitutes a fourth processing section.

[0077] <Configuration of the first to third guard processing units 63J, 63K, 63L> Next, a description will be given of the configuration of the first to third guard processing units 63J, 63K, and 63L. The first to third guard processing units 63J, 63K, and 63L basically have the same configuration.

[0078] 4, the first guard processing unit 63J has a setting unit 71. The setting unit 71 has a first determination unit 71A and a first switch 71B. The first determination unit 71A determines whether the vehicle speed V detected by the vehicle speed sensor 41 is equal to or greater than the first vehicle speed threshold V stored in the memory. th1 The first vehicle speed threshold V th1is set based on the vehicle speed at which an emergency avoidance maneuver may be performed via the steering wheel 5. The first vehicle speed threshold V th1 is the vehicle speed in the so-called low speed range, and is set to, for example, 20 km / h. This is because the probability of an emergency avoidance maneuver being performed is low when the vehicle is traveling at an extremely low speed, for example, 5 km / h or less. The low speed range is, for example, a speed range above 0 km / h and below 40 km / h.

[0079] The first determination unit 71A determines whether the vehicle speed V is greater than the first vehicle speed threshold V. th1 The first determination unit 71A determines whether or not there is a risk of an emergency avoidance maneuver being performed based on the comparison result between the vehicle speed V and the first vehicle speed threshold V th1 The first determination unit 71A sets the value of the first flag F1 based on the result of the comparison with the first vehicle speed threshold V. th1 If the vehicle speed V is smaller than the first vehicle speed threshold V, it is determined that there is no risk of an emergency avoidance operation being performed, and the value of the first flag F1 is set to "0." th1 If the difference is greater than 0.05, it is determined that there is a risk of an emergency avoidance maneuver being performed, and the value of the first flag F1 is set to "1."

[0080] The first switch 71B receives as data input a first set value G1 stored in memory and a second set value G2 stored in memory. The first set value G1 is a fixed value, for example, "1." The second set value G2 is a value specific to the first guard processing unit 63J. The second set value G2 is a fixed value that is set to a value greater than "1."

[0081] The first switch 71B receives, as a control input, the value of the first flag F1 set by the first determination unit 71A. The first switch 71B sets the value of the third set value G3 based on the value of the first flag F1. When the value of the first flag F1 is "0," the first switch 71B selects the first set value G1 (here, "1") as the third set value G3. When the value of the first flag F1 is "1," the first switch 71B sets the second set value G2 as the third set value G3.

[0082] The first guard processing unit 63J has a second determination unit 72, a second switch 73, a gradual change processing unit 74, a multiplier 75, a sign inversion processing unit 76, and a limiting processing unit 77. The second determination unit 72 determines whether the vehicle speed V detected by the vehicle speed sensor 41 is equal to or greater than the second vehicle speed threshold V stored in the memory. th2 The second vehicle speed threshold V th2 is set based on the vehicle speed at which an emergency avoidance maneuver may be performed via the steering wheel 5. The second vehicle speed threshold V th2 is set to a vehicle speed in the low speed range. th2 is the first vehicle speed threshold V th1 may be the same value as

[0083] The second determination unit 72 determines the vehicle speed V and the second vehicle speed threshold V th2 The second determination unit 72 determines whether there is a risk of an emergency avoidance maneuver being performed based on the comparison result between the vehicle speed V and the second vehicle speed threshold V th2 The second determination unit 72 sets the value of the second flag F2 based on the result of the comparison with the second vehicle speed threshold V. th2 If the vehicle speed V is smaller than the second vehicle speed threshold V, it is determined that there is no risk of an emergency avoidance operation being performed, and the second determination unit 72 sets the value of the second flag F2 to "0." th2 If the difference is greater than 1, it is determined that there is a risk of an emergency avoidance maneuver being performed, and the value of the second flag F2 is set to "1."

[0084] The second switch 73 receives as data input the third set value G3 set by the first switch 71B and the fourth set value G4 stored in memory. The fourth set value G4 is a fixed value, for example, "1."

[0085] The second switch 73 receives, as a control input, the value of the second flag F2 set by the second determination unit 72. The second switch 73 sets a fifth set value G5 based on the value of the second flag F2. When the value of the second flag F2 is "0," the second switch 73 selects the fourth set value G4 (here, "1") as the fifth set value G5. When the value of the second flag F2 is "1," the second switch 73 selects the third set value G3 as the fifth set value G5.

[0086] The gradual change processing unit 74 receives the fifth set value G5 selected by the second switch 73. The gradual change processing unit 74 calculates a sixth set value G6 by performing gradual change processing on the fifth set value G5 over time. The gradual change processing is processing for gradually changing the fifth set value G5. The gradual change processing unit 74 is configured to, for example, perform so-called time change amount guard processing, which limits the amount of change in the fifth set value G5 per unit time to a predetermined limit value. The sixth set value G6 is ultimately set to the fifth set value G5. Incidentally, a low-pass filter may be used as the gradual change processing unit 74.

[0087] The multiplier 75 multiplies the basic limit value T pth and the sixth set value G6 calculated by the gradual change processing unit 74. pth is the fifth torque command value T p5 is set to, for example, the rated torque of the steering motor 31. pth is stored in memory as a default value. The multiplier 75 multiplies the basic limit value T pth is multiplied by a sixth set value G6 calculated by the gradual change processing unit 74 to obtain the upper limit value T pUL Calculate the following.

[0088] The sign inversion processing unit 76 converts the upper limit value T pUL The sign inversion processing unit 76 takes in the upper limit value T pUL By inverting the sign of pLL Calculate the following.

[0089] The limiting unit 77 multiplies the upper limit T pUL and the lower limit value T calculated by the sign inversion processing unit 76. pLL The limiting processing unit 77 takes in the upper limit value T pUL and the lower limit T pLL and the fifth torque command value T p5 Perform the restriction process.

[0090] The limiting processing unit 77 limits the fifth torque command value T p5 and upper limit T pUL The limiting processor 77 compares the fifth torque command value T p5 is the upper limit T pUL If it exceeds the fifth torque command value T p5 The upper limit T pUL The upper limit T pUL The fifth torque command value T p5 is the sixth torque command value T p6 This becomes:

[0091] The limiting processing unit 77 limits the fifth torque command value T p5 and the lower limit T pLL The limiting processor 77 compares the fifth torque command value T p5 is the lower limit T pLL If the torque command value is less than the fifth torque command value T p5 Lower limit T pLL The lower limit T pLL The fifth torque command value T p5 is the sixth torque command value T p6 This becomes:

[0092] The limiting processing unit 77 limits the fifth torque command value T p5 is the upper limit T pUL and the lower limit TpLL If the fifth torque command value T p5 The fifth torque command value T calculated by the first adder 63I is not limited. p5 However, the sixth torque command value T p6 This becomes:

[0093] <Limit value setting pattern> Upper limit T pUL and the lower limit T pLL The setting patterns are as follows: When the value of the second flag F2 is "0", the fourth set value G4 is set as the fifth set value G5. The fourth set value G4 is, for example, "1". Therefore, the fifth set value G5 is set to "1". The fifth set value G5 is set as the sixth set value G6 via the gradual change processing unit 74. Since the fifth set value G5 is "1", the sixth set value G6 will eventually become "1". The basic limit value T stored in the memory pth However, the upper limit T pUL Also, the upper limit T pUL The sign of is inverted, and the lower limit T pLL The third set value G3 is set to the upper limit T pUL is not used in the calculation of

[0094] When the value of the second flag F2 is "1", the third set value G3 is set as the fifth set value G5. When the value of the first flag F1 is "0", the first set value G1 is set as the third set value G3. The first set value G1 is, for example, "1". Therefore, the fifth set value G5 is set to "1". The fifth set value G5 is set as the sixth set value G6 via the gradual change processing unit 74. Since the fifth set value G5 is "1", the sixth set value G6 will eventually become "1". That is, the basic limit value T stored in the memory pth However, the upper limit T pUL Also, the upper limit T pUL The sign of is inverted, and the lower limit T pLL is set.

[0095] When the value of the second flag F2 is "1", the third set value G3 is set as the fifth set value G5. When the value of the first flag F1 is "1", the second set value G2 is set as the third set value G3. The second set value G2 is a value greater than the first set value G1. Therefore, the third set value G3 is a value greater than the first set value G1. Here, since the first set value G1 is "1", the third set value G3 is a value greater than "1". In other words, the third set value G3 having a value greater than "1" is set as the fifth set value G5. The fifth set value G5 is set as the sixth set value G6 via the gradual change processing unit 74.

[0096] Since the fifth set value G5 has a value greater than "1", the sixth set value G6 will eventually become a value greater than "1". pth The upper limit value T obtained by multiplying the sixth set value G6 by pUL is the basic limit value T pth The upper limit T pUL The sign of is inverted, and the lower limit T pLL is set. Lower limit T pLL The absolute value of the basic limit value T pth Therefore, the absolute value of the basic restriction value T pth is the upper limit T pUL Compared to when it is used as the fifth torque command value T p5 The range of change is expanded.

[0097] The second guard processing unit 63K and the third guard processing unit 63L basically have the same configuration as the first guard processing unit 63J. As indicated by the parenthesized symbols in FIG. 4, the second guard processing unit 63K uses a seventh setting value G7 instead of the second setting value G2. The seventh setting value G7 is a value specific to the second guard processing unit 63K. The seventh setting value G7 is a fixed value, and is set to a value greater than "1", for example. The basic limit value T pth is the third torque command value T p3 It is also a fundamental limit for

[0098] Therefore, when the value of the second flag F2 is "0", and when the value of the second flag F2 is "1" and the value of the first flag F1 is "0", the basic limit value T pth is the upper limit T pUL The upper limit T pUL The sign of is inverted, and the lower limit T pLL When the value of the second flag F2 is "1" and the value of the first flag F1 is "1", the basic limit value T pth is the upper limit T pUL Compared to when the third torque command value T p3 The range of change is expanded.

[0099] As indicated by the parenthesized symbols in FIG. 4, the third guard processing unit 63L uses an eighth set value G8 instead of the second set value G2. The eighth set value G8 is a value specific to the third guard processing unit 63L. The eighth set value G8 is a fixed value, and is set to a value greater than "1", for example. The basic limit value T pth is the fourth torque command value T p4 It is also a fundamental limit for

[0100] Therefore, when the value of the second flag F2 is "0", and when the value of the second flag F2 is "1" and the value of the first flag F1 is "0", the basic limit value T pth is the upper limit T pUL The upper limit T pUL The sign of is inverted, and the lower limit T pLL When the value of the second flag F2 is "1" and the value of the first flag F1 is "1", the basic limit value T pth is the upper limit T pUL Compared to when it is used as the fourth torque command value T p4 The range of change is expanded.

[0101] <Operation of the First Embodiment> Next, the operation of the first embodiment will be described. As a comparative example, the first guard processing unit 63J, the second guard processing unit 63K, and the third guard processing unit 63L set the basic limit value T pth In this case, for example, when an emergency avoidance operation is performed via the steering wheel 5, the following concerns arise. However, in this case, the fourth torque command value T p4 and the fifth torque command value T p5 Focus on the relationship between.

[0102] As shown in the graph of FIG. 5, the fourth torque command value T p4 and the fifth torque command value T calculated by the first adder 63I. p5 The absolute value of increases over time, and eventually reaches the basic restriction value T pth For example, the fifth torque command value T p5 The gradient of the absolute value of the fourth torque command value T p4 The slope is the rate of change of the absolute value of the torque command value with respect to time. Therefore, the fourth torque command value T p4 The absolute value of the fifth torque command value T p5 The absolute value of the basic restriction value T pth (time T1).

[0103] Fourth torque command value T p4 The absolute value of the basic limit value T pth After reaching the fifth torque command value T p5 and the fourth torque command value T p4 The absolute value of both is the basic limit value T pth That is, the fourth torque command value T p4 and the fifth torque command value T p5 The absolute value of the fourth torque command value T p4 is the value subtracted by the third subtractor 63N. Therefore, the fourth torque command value T p4 The absolute value of the basic limit value T pth After reaching the fourth torque command value T p4and the fifth torque command value T p5 Therefore, there is a concern that the steered wheels 6 may not be able to be steered appropriately in response to an emergency avoidance operation via the steering wheel 5.

[0104] In contrast to this, in this embodiment, when there is a risk that an emergency avoidance operation will be performed via the steering wheel 5, the third to fifth torque command values ​​T p3 ~T p5 When there is a risk of a sudden avoidance maneuver being performed, for example, the first vehicle speed threshold V th1 and a second vehicle speed threshold V th2 This is the case when a vehicle travels at a speed exceeding .

[0105] In this embodiment, the third to fifth torque command values ​​T p3 ~T p5 Two patterns are envisaged to expand the range of variation for each of the above. Either the first or second pattern is adopted depending on the product specifications.

[0106] In the first pattern, the second setting value G2 used by the first guard processing unit 63J, the seventh setting value G7 used by the second guard processing unit 63K, and the eighth setting value G8 used by the third guard processing unit 63L are all set to the same value, except that the second setting value G2, the seventh setting value G7, and the eighth setting value G8 are all set to values ​​greater than "1."

[0107] The second pattern is a pattern in which the second set value G2 used by the first guard processing unit 63J, the seventh set value G7 used by the second guard processing unit 63K, and the eighth set value G8 used by the third guard processing unit 63L are set to different values. However, the second set value G2, the seventh set value G7, and the eighth set value G8 are all set to values ​​greater than "1." Furthermore, of the second set value G2 and the seventh set value G7, at least the second set value G2 is set to a value greater than the eighth set value G8. This is because the first torque command value T calculated by the proportional control unit 63E is p1 The steering torque command value T p * This is to reflect this.

[0108] <First pattern> The operation when the first pattern is adopted will be described. Here, the fourth torque command value T p4 and the fifth torque command value T p5 This is the fifth torque command value T p5 is the first torque command value T calculated by the proportional control section 63E. p1 and the second torque command value T calculated by the integral control unit 63F. p2 and the eighth set value G8 is a value obtained by adding the second set value G2 and the eighth set value G8 together, and the value has a greater effect on the steering performance of the steered wheels 6. In addition, as an example, the second set value G2 and the eighth set value G8 are both set to "3."

[0109] As shown in the graph of FIG. 6, the fourth torque command value T p4 and the fifth torque command value T p5 The limit values ​​for the absolute values ​​of are the basic limit values ​​T pth It is three times the value.

[0110] Fifth torque command value T p5 The absolute value of the fifth torque command value T p5 The absolute value of the basic limit value T pth Eventually, the basic limit T pthThe fifth torque command value T p5 After the absolute value of reaches the limit value, the fifth torque command value T p5 The absolute value of is kept limited to a limit value.

[0111] Fourth torque command value T p4 The absolute value of the fourth torque command value T p4 The absolute value of the basic limit value T pth Eventually, the basic limit T pth The fourth torque command value T p4 After the absolute value of the fourth torque command value T p4 The absolute value of the basic limit value T pth and the basic limit T pth The saturated value is maintained between the limit value and three times the value of the

[0112] In this way, the fourth torque command value T p4 and the fifth torque command value T p5 The limit value for the absolute value of pth This increases the fourth torque command value T p4 and the fifth torque command value T p5 Therefore, the absolute value of the fourth torque command value T p4 and the fifth torque command value T p5 The difference between the absolute value of the fourth torque command value T p4 and the fifth torque command value T p5 The cancellation of these effects is suppressed.

[0113] <Second pattern> The operation when the second pattern is adopted will be described. Here, the fourth torque command value T p4 and the fifth torque command value T p5 As an example, the second set value G2 is set to "5" and the eighth set value G8 is set to "2."

[0114] As shown in the graph of FIG. 7, the fourth torque command value T p4 The limit value for the absolute value of is the basic limit value T pth The fifth torque command value T p5 The limit value for the absolute value of is the basic limit value T pth This is five times the value.

[0115] Fifth torque command value T p5 The absolute value of the fifth torque command value T p5 The absolute value of the basic limit value T pth Eventually, the basic limit T pth The fifth torque command value T p5 After the absolute value of saturates, the fifth torque command value T p5 The absolute value of the basic limit value T pth and the basic limit T pth The saturated value is maintained between the limit value and five times the value of the

[0116] Fourth torque command value T p4 The absolute value of the fourth torque command value T p4 The absolute value of the basic limit value T pth Eventually, the basic limit T pth The fourth torque command value T p4 After the absolute value of the fourth torque command value T p4 The absolute value of the basic limit value T pth and the basic limit T pth The saturated value is maintained between the limit value and twice the value of the

[0117] In this way, the fourth torque command value T p4 and the fifth torque command value T p5 The limit value for the absolute value of pth , and the fourth torque command value T p4 and the fifth torque command value T p5Therefore, the absolute value of the fourth torque command value T p4 and the fifth torque command value T p5 The difference between the absolute value of the fourth torque command value T p4 and the fifth torque command value T p5 The cancellation of these effects is suppressed.

[0118] <Advantages of the First Embodiment> The first embodiment provides the following advantages. (1-1) The fourth torque command value T p4 and the fifth torque command value T p5 For example, if there is a risk of an emergency avoidance operation being performed via the steering wheel 5, the limit values ​​for the fourth torque command value T p4 and the fifth torque command value T p5 The limit value for both is the basic limit value T pth That is, the fourth torque command value T p4 The change range of the fifth torque command value T p5 The range of change of the fourth torque command value T p4 and the fifth torque command value T p5 The fourth torque command value T p4 and the fifth torque command value T p5 The difference between the fourth torque command value T p4 and the fifth torque command value T p5 The fifth torque command value T p5 is the first torque command value T calculated by the proportional control section 63E. p1 and the second torque command value T calculated by the integral control unit 63F. p2 and this value has a greater effect on the steering performance of the steered wheels 6. Therefore, the steered wheels 6 can be steered appropriately in response to an emergency avoidance operation via the steering wheel 5.

[0119] (1-2) Basic limit value T pth When the fifth set value G5, which is multiplied by the torque command value T, is switched between the third set value G3 and the fourth set value G4, the gradual change processing unit 74 executes gradual change processing on the fifth set value G5. p3 The limit value for the fourth torque command value T p4 and the fifth torque command value T p5 Therefore, the sudden change of the limit value for the steering torque command value T p * This in turn suppresses sudden changes in the steering force generated by the steering motor 31.

[0120] (1-3) The vehicle speed V is equal to or exceeds the first vehicle speed threshold V th1 and exceeds the second vehicle speed threshold V th2 When the torque command value T p4 and the fifth torque command value T p5 The limit value for the absolute value of pth The first vehicle speed threshold V th1 and exceeds the second vehicle speed threshold V th2 A state in which the vehicle is traveling at a speed exceeding 1 / 2 is one of the vehicle states in which a sudden avoidance maneuver may be performed. Therefore, the fourth torque command value T p4 The change range of the limit value for the absolute value of and the fifth torque command value T p5 The range of change of the limit value for the absolute value of can be expanded.

[0121] (1-4) When the second pattern for expanding the range of change of the limit value is adopted, the vehicle speed V is greater than the first vehicle speed threshold V th1 and exceeds the second vehicle speed threshold V th2 When the torque command value T p5 The limit value for the fourth torque command value T p4 Therefore, the fifth torque command value T calculated by the first adder 63I is set to a value greater than the limit value for p5, and the first torque command value T calculated by the proportional control section 63E. p1 , and the second torque command value T calculated by the integral control unit 63F. p2 The steering torque command value T p * can be reflected in.

[0122] <Second embodiment> Next, a second embodiment of a steering control device will be described. This embodiment basically has the same configuration as the first embodiment shown in Figures 1, 2 and 4. This embodiment differs from the first embodiment in the configuration of pinion angle feedback control unit 63. Therefore, the same components as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

[0123] 8, the pinion angle feedback control unit 63 has a first subtractor 63A, a first differentiator 63B, a second differentiator 63C, and a second subtractor 63D. The pinion angle feedback control unit 63 also has a proportional control unit 63E, an integral control unit 63F, a differential control unit 63G, and a damping control unit 63H. The pinion angle feedback control unit 63 also has a second guard processing unit 63K and a third guard processing unit 63L.

[0124] In addition to these components, the pinion angle feedback control unit 63 has a fifth guard processing unit 63P, a sixth guard processing unit 63Q, a calculator 63R, and a seventh guard processing unit 63S.

[0125] The fifth guard processing unit 63P and the sixth guard processing unit 63Q have the same configuration as the first adder 63I, the first guard processing unit 63J, the second guard processing unit 63K, and the third guard processing unit 63L shown in Figure 4 above.

[0126] The fifth guard processing unit 63P is configured to calculate the first torque command value T p1and the vehicle speed V detected by the vehicle speed sensor 41. The fifth guard processing unit 63P calculates the first torque command value T p1 The limit value is calculated based on the first torque command value T p1 The fifth guard processing unit 63P determines the first torque command value T based on the upper and lower limits. p1 The fifth guard processing unit 63P executes a limiting process for the eleventh torque command value T p11 Calculate the following.

[0127] As indicated by the parenthesized symbols in FIG. 4, the fifth guard processing unit 63P uses a ninth setting value G9 instead of the second setting value G2. The ninth setting value G9 is a value specific to the fifth guard processing unit 63P. The ninth setting value G9 is a fixed value, and is set to a value greater than "1", for example. The basic limit value T pth is the first torque command value T p1 It is also a fundamental limit for

[0128] The sixth guard processing unit 63Q calculates the second torque command value T p2 and the vehicle speed V detected by the vehicle speed sensor 41. The sixth guard processing unit 63Q calculates the second torque command value T p2 The limit value is calculated based on the second torque command value T p2 The sixth guard processing unit 63Q determines the second torque command value T based on the upper and lower limits. p2 The sixth guard processing unit 63Q executes the limiting process for the twelfth torque command value T p12 Calculate the following.

[0129] As indicated by the parenthesized symbols in FIG. 4, the sixth guard processing unit 63Q uses a tenth set value G10 instead of the second set value G2. The tenth set value G10 is a value specific to the sixth guard processing unit 63Q. The tenth set value G10 is a fixed value, and is set to a value greater than "1", for example. The basic limit value Tpth is the second torque command value T p2 It is also a fundamental limit for

[0130] The calculator 63R calculates the eleventh torque command value T p11 and the twelfth torque command value T calculated by the sixth guard processing unit 63Q. p12 and the seventh torque command value T calculated by the second guard processing unit 63K. p7 and the eighth torque command value T calculated by the third guard processing unit 63L. p8 The calculator 63R takes in the eleventh torque command value T p11 and the 12th torque command value T p12 and the seventh torque command value T p7 and the eighth torque command value T p8 By subtracting p13 Calculate the following.

[0131] The seventh guard processing unit 63S calculates the thirteenth torque command value T p13 The seventh guard processing unit 63S takes in the thirteenth torque command value T p13 The limit value is the thirteenth torque command value T p13 The seventh guard processing unit 63S determines a thirteenth torque command value T based on the upper and lower limits. p13 Through the execution of the limiting process, the seventh guard processing unit 63S performs limiting processing on the final steering torque command value T p * Calculate the following.

[0132] The fifth guard processing unit 63P and the sixth guard processing unit 63Q constitute a third processing unit, and the computing unit 63R constitutes a fourth processing unit. <Advantages of the second embodiment> The second embodiment has the following advantages in addition to the advantages (1-2), (1-3), and (1-4) of the first embodiment.

[0133] (2-1) The first to fourth torque command values ​​T p1 ~T p4 For example, if there is a risk that an emergency avoidance operation will be performed via the steering wheel 5, the first to fourth torque command values ​​T p1 ~T p4 The limit value for each absolute value is the basic limit value T pth That is, the first to fourth torque command values ​​T p1 ~T p4 As a result, the range of change of each of the first to third torque command values ​​T p1 ~T p3 and the fourth torque command value T p4 Therefore, the absolute values ​​of the first to third torque command values ​​T p1 ~T p3 and the fourth torque command value T p4 The difference between the absolute values ​​of the first to third torque command values ​​T p1 ~T p3 and the fourth torque command value T p4 In particular, the first torque command value T p1 and the fourth torque command value T p4 Since the above-mentioned forces are prevented from cancelling each other out, the steered wheels 6 can be appropriately steered in response to an emergency avoidance operation performed via the steering wheel 5.

[0134] <Third embodiment> Next, a third embodiment of a steering control device will be described. This embodiment basically has the same configuration as the first embodiment shown in Figs. 1, 2 and 4 above. This embodiment differs from the first embodiment in the configuration of setting section 71 in pinion angle feedback control section 63. Therefore, the same components as those in the first embodiment are given the same reference numerals, and detailed description thereof will be omitted. This embodiment may also be applied to the second embodiment shown in Fig. 8 above.

[0135] 4 calculates the third set value G3 using a map stored in memory. <When the first pattern is adopted> Third to fifth torque command values ​​T p3 ~T p5 When the first pattern for expanding the range of change of each of the first guard processing unit 63J, the second guard processing unit 63K, and the third guard processing unit 63L is adopted, the setting unit 71 that each has uses the first map.

[0136] As shown in the graph of FIG. 9, the first map M1 is a map with the horizontal axis representing the vehicle speed V and the vertical axis representing the third set value G3, and defines the relationship between the vehicle speed V and the third set value G3. The first map M1 has the following characteristics. That is, as the value of the vehicle speed V ranges from "0" to the first vehicle speed threshold V th1 A dead band is set in the range from the first vehicle speed threshold V to the third set value G3 of "1". th1 When the vehicle speed V exceeds the predetermined value G3, the third set value G3 increases linearly as the vehicle speed V increases.

[0137] Therefore, when the value of the vehicle speed V is equal to or exceeds the first vehicle speed threshold V th1 After exceeding the third torque command value T p3 and the fourth torque command value T p4 and the fifth torque command value T p5 The limit value of both the basic limit value T pth As the value of the vehicle speed V increases, the third torque command value T p3 limit value, the fourth torque command value T p4 and the fifth torque command value T p5 The limit value of increases.

[0138] Incidentally, when this embodiment is applied to the second embodiment, the setting units 71 of the fifth guard processing unit 63P and the sixth guard processing unit 63Q also use the first map M1 shown in FIG.

[0139] <When the second pattern is adopted> Third to fifth torque command values ​​T p3 ~T p5 When the second pattern for expanding the range of change of each of the first guard processing unit 63J, the second guard processing unit 63K, and the third guard processing unit 63L is adopted, the setting units 71 of the first guard processing unit 63J, the second guard processing unit 63K, and the third guard processing unit 63L each use the second map, but the second maps used by each setting unit 71 have different characteristics.

[0140] As shown in the graph of FIG. 10, the second map M2 is a map with the vehicle speed V on the horizontal axis and the third set value G3 on the vertical axis, and defines the relationship between the vehicle speed V and the third set value G3. The second map M2 used by the setting unit 71 of the first guard processing unit 63J has the following characteristics. That is, as shown by the characteristic line L1, the value of the vehicle speed V changes from "0" to the first vehicle speed threshold V th1 A dead band is set in the range from the first vehicle speed threshold V to the third set value G3 of "1". th1 When the vehicle speed V exceeds the predetermined value G3, the third set value G3 increases linearly as the vehicle speed V increases.

[0141] The second map M2 used by the setting unit 71 of the second guard processing unit 63K has the following characteristics. That is, as shown by the characteristic line L2, the value of the vehicle speed V changes from "0" to the first vehicle speed threshold V th1 A dead band is set in the range from the first vehicle speed threshold V to the third set value G3 of "1". th1 When the vehicle speed V exceeds the first vehicle speed threshold V, the third set value G3 increases linearly as the vehicle speed V increases. th1 The characteristic line L2 after the vehicle speed V exceeds the first vehicle speed threshold V th1 The slope of the characteristic line L1 is smaller than that of the characteristic line L2 after the vehicle speed V has passed the threshold value V. The slope of the characteristic line L1 is the rate of change of the third set value G3 relative to the vehicle speed V.

[0142] The second map M2 used by the setting unit 71 of the third guard processing unit 63L has the following characteristics. That is, as shown by the characteristic line L3, the value of the vehicle speed V changes from "0" to the first vehicle speed threshold V th1 A dead band is set in the range from the first vehicle speed threshold V to the third set value G3 of "1". th1 When the vehicle speed V exceeds the first vehicle speed threshold V, the third set value G3 increases linearly as the vehicle speed V increases. th1 The characteristic line L3 after the vehicle speed V exceeds the first vehicle speed threshold V th1 The slope is even smaller than that of the characteristic line L2 after passing through

[0143] Therefore, when the value of the vehicle speed V is equal to or exceeds the first vehicle speed threshold V th1 After exceeding the third torque command value T p3 and the fourth torque command value T p4 and the fifth torque command value T p5 The limit value of both the basic limit value T pth As the value of the vehicle speed V increases, the third torque command value T p3 limit value, the fourth torque command value T p4 and the fifth torque command value T p5 The limit value of increases.

[0144] Incidentally, when this embodiment is applied to the second embodiment, the second map M2 used by each setting unit 71 of the fifth guard processing unit 63P and the sixth guard processing unit 63Q has characteristics, for example, as shown by the characteristic line L1 in Figure 10.

[0145] <Advantages of the third embodiment> The third embodiment has the following advantages in addition to the advantages (1-1), (1-2), (1-3), and (1-4) of the first embodiment and (2-1) of the second embodiment.

[0146] (3-1) The value of the vehicle speed V is equal to or exceeds the first vehicle speed threshold V th1When the vehicle speed V exceeds the predetermined value, the third torque command value T p3 limit value, the fourth torque command value T p4 and the fifth torque command value T p5 Therefore, the limit value of the third torque command value T p3 limit value, the fourth torque command value T p4 and the fifth torque command value T p5 The higher the vehicle speed V, the more it is required to steer the steered wheels 6 appropriately in response to an emergency avoidance operation via the steering wheel 5.

[0147] <Other embodiments> Each embodiment may be modified as follows. In the second embodiment, the second torque command value T calculated by the integral control unit 63F p2 The sixth guard processing unit 63Q for the second torque command value T p2 In this case, the sixth guard processing unit 63Q may be configured to keep the basic limit value T pth The second torque command value T p2 Limit.

[0148] In the first to third embodiments, a configuration in which fourth guard processing section 63O is omitted may be adopted as pinion angle feedback control section 63. In this case, tenth set value G10 calculated by third subtractor 63N is used as final steering torque command value T p * This becomes:

[0149] In the first to third embodiments, the pinion angle feedback control unit 63 may be configured to omit the differential control unit 63G and the second guard processing unit 63K. In this case, the first differentiator 63B, the second subtractor 63D, and the second adder 63M can be omitted. The third subtractor 63N subtracts the sixth torque command value T calculated by the first guard processing unit 63J. p6 Import.

[0150] In the first to third embodiments, the guard processing units (63J, 63K, 63L, 63P, 63Q) may be configured without the gradual change processing unit 74. In this case, the multiplier 75 receives the fifth set value G5 set by the second switch 73.

[0151] In the first to third embodiments, the first vehicle speed threshold V th1 , and a second vehicle speed threshold V th2 The first vehicle speed threshold V may be changed as needed. th1 , and a second vehicle speed threshold V th2 may be a speed in the medium speed range or a speed in the high speed range. The medium speed range is, for example, a speed range of 40 km / h or more and less than 60 km / h. The high speed range is, for example, a speed range of 60 km / h or more. That is, the first vehicle speed threshold V th1 , and a second vehicle speed threshold V th2 may be set to a speed within the range of 20 km / h or more and 100 km / h or less, for example.

[0152] In the first to third embodiments, the vehicle speed V may be calculated based on the wheel speed detected by a wheel speed sensor. Alternatively, the vehicle speed V may be based on a signal other than the wheel speed. For example, the vehicle speed V may be the vehicle speed detected by a vehicle speed sensor. The vehicle speed is the speed of the vehicle relative to the road surface. When the vehicle speed is used, the influence of tire slippage can be eliminated. Alternatively, the first determination unit 71A shown in FIG. 4 may take in a speed based on the wheel speed, while the second determination unit 72 may take in the vehicle speed.

[0153] In the first to third embodiments, instead of or in addition to the vehicle speed V, each torque command value (T p3 ,T p4 ,T p5 or T p1 ,T p2 ,T p3 ,T p4 ) limit value may be changed. Each of the vehicle state variables B1 to B4 reflects the vehicle's running state. The vehicle's running state includes, for example, the vehicle behavior associated with an emergency avoidance maneuver. As an emergency avoidance maneuver occurs, the values ​​of each of the vehicle state variables B1 to B4 increase. This is because, during an emergency avoidance maneuver, the operation amount and steering speed of the steering wheel 5 increase rapidly. The first determination unit 71A and the second determination unit 72 determine that there is a risk of an emergency avoidance maneuver being performed when, for example, the value of each of the vehicle state variables B1 to B4 exceeds a predetermined threshold value.

[0154] B1. Yaw rate B2.Lateral acceleration B3. Target pinion angle θ p * and the actual pinion angle θ p The ratio of (θ p * / θ p ) B4. Target pinion angular velocity ω p * and the actual pinion angular velocity ω p The ratio of (ω p * / ω p ) The yaw rate is detected, for example, by a yaw rate sensor mounted on the vehicle, and the lateral acceleration is detected by a lateral acceleration sensor mounted on the vehicle. [Explanation of symbols]

[0155] 1B...Steering control device 5...Steering wheel 6...Steering wheel 21...Pinion shaft (rotating body) 31...Steering motor 63E... Proportional control section (first processing section) 63F...Integral control section (first processing section) 63G... Differential control section (first processing section) 63H...Damping control section (second processing section) 63J...First guard processing section (third processing section) 63K...Second guard processing section (third processing section) 63L...Third guard processing section (third processing section) 63N...Third subtractor (fourth processing unit) 63P...Fifth guard processing section (third processing section) 63Q...6th guard processing section (3rd processing section) 63R...Calculator (fourth processing unit) 74...gradually changing processing part

Claims

1. A steering control device that calculates a target angle of a rotating body that rotates in conjunction with the operation of a steered wheel in accordance with a steering state of a steering wheel to control a steering motor that generates a steering force for steering the steered wheels of a vehicle, and calculates a steering torque command value for the steering motor by executing feedback control that causes an actual angle of the rotating body to follow the target angle, a first processing unit that calculates a torque command value according to a deviation between the target angle and the actual angle; a second processing unit that calculates a compensation value for the torque command value based on a target angular velocity or an actual angular velocity of the rotating body, the compensation value acting in a direction opposite to the torque command value; a third processing unit that performs a limiting process to limit a change range of the torque command value and the compensation value based on limit values ​​that are respectively set for the torque command value and the compensation value; a fourth processing unit that calculates the steering torque command value using the torque command value after the limiting process has been performed and the compensation value after the limiting process has been performed, The third processing unit is a steering control device that individually increases the limit values ​​set for the torque command value and the compensation value in accordance with a running state of the vehicle.

2. 2. The steering control device according to claim 1, wherein the third processing unit increases the limit value when a value of a vehicle state variable that reflects the running state of the vehicle exceeds a predetermined threshold value.

3. 3. The steering control device according to claim 2, wherein the third processing unit increases the limit values ​​set for the torque command value and the compensation value to the same value when the value of the vehicle state variable exceeds the threshold value.

4. 3. The steering control device according to claim 2, wherein the third processing unit increases the limit values ​​set for the torque command value and the compensation value to values ​​different from each other when the value of the vehicle state variable exceeds the threshold value.

5. 5. The steering control device according to claim 4, wherein the limit value for the torque command value is greater than the limit value for the compensation value.

6. The turning control device according to any one of claims 2 to 5, wherein the third processing unit increases the limit value as the value of the vehicle state variable increases when the value of the vehicle state variable exceeds the threshold value.

7. The value of the vehicle state variable is a value of a vehicle speed detected by an on-board sensor, a value of a yaw rate, a value of a ratio between the target angle and the actual angle, or a value of a ratio between the target angular velocity and the actual angular velocity.

8. The steering control device according to any one of claims 2 to 5, wherein the third processing unit determines that there is a risk of an emergency avoidance operation being performed via the steering wheel when the value of the vehicle state variable exceeds the threshold value.

9. The steering control device according to any one of claims 1 to 5, wherein the third processing unit has a gradual change processing unit that, when changing the limit value, performs gradual change processing on the limit value to gradually change the limit value over time.

10. the torque command value is a first torque command value proportional to the deviation calculated by performing a proportional calculation on the deviation; a second torque command value proportional to an integral value of the deviation calculated by performing an integral calculation on the deviation, The turning control device according to any one of claims 1 to 5, wherein the third processing unit limits a range of change of the sum of the first torque command value and the second torque command value, based on the limit value determined for the sum.

11. the torque command value is a first torque command value proportional to the deviation calculated by performing a proportional calculation on the deviation; a second torque command value proportional to an integral value of the deviation calculated by performing an integral calculation on the deviation, 6. The steering control device according to claim 1, wherein the third processing unit limits change ranges of the first torque command value and the second torque command value, based on the limit values ​​determined for the first torque command value and the second torque command value, respectively.

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