Steering control device

Abstract

A steering control device (50) controls a motor (21) that drives a steering device (10) that steers a steering wheel (12) of a vehicle. The steering control device (50) executes feedback control that causes an actual angle (θp) to follow a target rotation angle (θp_med *) of a shaft (23) that rotates in conjunction with a turning operation of the steering wheel (12), and on the basis of a state variable (θp_med *) of the vehicle, an estimated value (ζ) of a human body motion index indicating movement of a human body that affects the ride comfort or discomfort of the occupant of the vehicle is calculated, on the basis of the estimated value (ζ) of the human body motion index, whether or not the human body motion index (ζ) has reached a degree to be suppressed is determined, and, when it is determined that the human body motion index is to be suppressed, the target rotation angle (θp_med *) is corrected so as to suppress the human body motion index.

Description

Steering control device

[0001] The present disclosure relates to a steering control device.

[0002] Conventionally, technologies for maintaining passenger comfort in vehicle motion control have been known. For example, a control device described in Patent Document 1 uses a human body behavior model to simulate posture control of a seated passenger when lateral acceleration is applied to the vehicle. The control device performs feedforward control of the input of lateral acceleration in order to suppress swaying of the passenger's head, taking into account the dynamic characteristics between the vehicle and the passenger obtained through the simulation. The human body behavior model is a model of human body behavior as an equivalent double inverted pendulum.

[0003] Japanese Patent Application Laid-Open No. 2021-062821

[0004] The human body behavior model has modeling errors. The modeling errors are errors that exist between the model and the actual object. Therefore, when the human body behavior model is directly used for vehicle control, as in Patent Document 1, the modeling errors may affect the control for suppressing the swaying of the occupant's head. It is therefore necessary to ensure more appropriate comfort for the occupant.

[0005] A steering control device according to one aspect of the present disclosure is configured to control a motor that drives a steering device that steers steered wheels of a vehicle. The steering control device includes: an angle feedback control unit configured to execute feedback control to make an actual angle follow a target rotation angle of a shaft that rotates in conjunction with the steering operation of the steered wheels; an estimation processing unit configured to calculate an estimated value of a human body motion index that indicates human body motion that affects the ride comfort or discomfort of an occupant of the vehicle based on state variables of the vehicle; a determination processing unit configured to determine whether the human body motion index has reached a level that should be suppressed based on the estimated value of the human body motion index calculated by the estimation processing unit; and a correction processing unit configured to correct the target rotation angle so that the human body motion index is suppressed when the determination processing unit determines that the human body motion index has reached a level that should be suppressed.

[0006] Fig. 1 is a configuration diagram of an electric power steering device equipped with a steering control device according to one embodiment. Fig. 2 is a block diagram of the motor and steering control device in Fig. 1. Fig. 3 is a block diagram of the command value calculation unit in Fig. 2. Fig. 4 is a block diagram of the jerk suppression processing unit in Fig. 3.

[0007] A steering control device according to one embodiment will be described. The steering control device controls, for example, an electric power steering device (hereinafter referred to as "EPS 10") of a vehicle. The EPS 10 is a type of steering device for a vehicle.

[0008] 1 , the EPS 10 mechanically couples power transmission between a steering wheel 11 and steered wheels 12. The EPS 10 has a steering shaft 13, a first pinion shaft 14, and a steered shaft 15.

[0009] A first end of the steering shaft 13 is connected to the steering wheel 11. A second end of the steering shaft 13 is connected to a first pinion shaft 14. The steered shaft 15 extends in the vehicle width direction. Both ends of the steered shaft 15 are connected to the steered wheels 12 via tie rods 16. The first pinion shaft 14 is arranged so as to intersect with the steered shaft 15. Pinion teeth 14a of the first pinion shaft 14 are meshed with first rack teeth 15a of the steered shaft 15. The steered shaft 15 moves linearly in conjunction with the rotation of the steering wheel 11. The linear movement of the steered shaft 15 is transmitted to the steered wheels 12 via the tie rods 16. As a result, the steered angle θ of the steered wheels 12 is ｗ changes.

[0010] EPS 10 includes a motor 21 and a reduction gear 22. Motor 21 generates assist torque. The assist torque is a force that assists the driver in steering steering wheel 11 and acts in the same direction as the driver's operation of steering wheel 11. Motor 21 is, for example, a three-phase brushless motor. Motor 21 is connected to second pinion shaft 23 via reduction gear 22. Pinion teeth 23a of second pinion shaft 23 mesh with second rack teeth 15b of steered shaft 15. The rotation of motor 21 is reduced by reduction gear 22. The reduced rotational force of motor 21 is transmitted to steered shaft 15 via second pinion shaft 23 as assist torque. Therefore, steered shaft 15 moves in the vehicle width direction in response to the rotation of motor 21. Second pinion shaft 23 is a shaft that rotates in conjunction with the steering operation of steered wheels 12.

[0011] The EPS 10 has a control device 50. The control device 50 is an example of a steering control device and has a processing circuit including 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 a memory.

[0012] A2: One or more dedicated hardware circuits such as an application specific integrated circuit (ASIC) that executes at least some of the various processes. A3: A hardware circuit that combines the two configurations A1 and A2.

[0013] 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 a RAM (Random Access Memory) and a ROM (Read Only Memory). The CPU executes the program stored in the memory at a predetermined calculation cycle to perform various controls.

[0014] The control device 50 controls the motor 21 based on the detection results of sensors mounted on the vehicle. The sensors include a torque sensor 51, a vehicle speed sensor 52, and a rotation angle sensor 53. The torque sensor 51 detects the steering torque T ｈ Detects the steering torque T ｈ is the torque applied to the steering shaft 13 through the rotation of the steering wheel 11. The vehicle speed sensor 52 detects the vehicle speed V. The rotation angle sensor 53 is provided on the motor 21. The rotation angle sensor 53 detects the rotation angle θ of the motor 21. ｍ Detect.

[0015] The control device 50 detects the rotation angle θ ｍ The control device 50 performs vector control of the motor 21 using the steering torque T ｈ The control device 50 controls the motor 21 to supply electric power so as to generate an assist torque corresponding to the steering torque T ｈ and vehicle speed V detected by vehicle speed sensor 52. The target assist torque is a target value of the assist torque generated by motor 21. Control device 50 controls the power supply to motor 21 so that the actual assist torque applied to steered shaft 15 matches the target assist torque.

[0016] In order to further improve the safety or convenience of the vehicle, a vehicle may be equipped with a driving assistance system that realizes various driving assistance functions or an automatic driving system that realizes an automatic driving function in which the system takes over driving. In this case, the vehicle is equipped with a host control device 500 that controls the control devices of the various on-board systems. The host control device 500 determines the optimal control method based on the state of the vehicle and issues individual control commands to each on-board control device according to the determined control method.

[0017] The host control device 500 intervenes in the steering control by the control device 50. The host control device 500 switches the driving assistance function or the automatic driving function between on and off through the operation of a switch (not shown) provided in the driver's seat or the like. When the driving assistance function or the automatic driving function is on, the host control device 500 issues, for example, a command angle θ for causing the vehicle to travel on a target lane. ＊ Calculate the command angle θ ＊ is the pinion angle θ required to make the vehicle travel along the lane depending on the vehicle's driving state. ｐ The target value of the command angle θ ＊ is the current pinion angle θ ｐ or the current target pinion angle θ ｐ ＊ Alternatively, an alternative angle may be used.

[0018] <Configuration of control device 50> Next, a detailed description will be given of the configuration of the control device 50. As shown in Fig. 2, the control device 50 controls the power supply to the motor 21. The control device 50 has a pinion angle calculation unit 61, a command value calculation unit 62, and a power supply control unit 63.

[0019] The pinion angle calculation unit 61 calculates the rotation angle θ of the motor 21 detected by the rotation angle sensor 53. ｍ Based on this, the pinion angle θ ｐ Calculate the pinion angle θ ｐ is the rotation angle of the second pinion shaft 23. The pinion angle calculation unit 61 calculates, for example, the rotation angle θ ｍ is divided by the reduction ratio of the reduction mechanism 22 to obtain the pinion angle θ ｐ Calculate the following.

[0020] The command value calculation unit 62 calculates the steering torque T ｈ and the vehicle speed V detected by the vehicle speed sensor 52, the assist command value T ＊ Assist command value T ＊ indicates the target value of the torque to be generated by the motor 21. ｈ The larger the absolute value of and the slower the vehicle speed V, the greater the assist command value T ＊The absolute value of becomes larger.

[0021] The power supply control unit 63 determines the assist command value T ＊ That is, the power supply control unit 63 supplies the motor 21 with electric power according to the assist command value T ＊ The current command value is a target value of the current to be supplied to the motor 21, and indicates the amount of current required for the motor 21 to generate a target assist torque.

[0022] The current control unit 63 detects the current I supplied to the motor 21 through the current sensor 64. ｍ The current sensor 64 is provided on the power supply path between the current control unit 63 and the motor 21. The current control unit 63 detects the current I ｍ That is, the current control unit 63 executes the feedback control of the current command value and the current I ｍ１ The deviation between the value of the assist command value T and the calculated deviation is eliminated by controlling the power supply to the motor 21. ＊ A torque corresponding to the

[0023] <Configuration of Command Value Calculation Unit 62> Next, a description will be given of the configuration of the command value calculation unit 62. As shown in Fig. 3, the command value calculation unit 62 has a first adder 71, an axial force calculation unit 72, a target steering torque calculation unit 73, a torque feedback control unit 74, a target angle calculation unit 75, an angle feedback control unit 76, and a second adder 77.

[0024] The first adder 71 calculates the steering torque T detected through the torque sensor 51. ｈ and the first assist torque T calculated by the torque feedback control unit 74. １ ＊ By adding these, the input torque T ｉｎ ＊ Calculate the input torque T ｉｎ ＊ is the torque applied to the steering shaft 13.

[0025] The axial force calculation unit 72 calculates, for example, the vehicle speed V detected by the vehicle speed sensor 52 and the current I of the motor 21 detected by the current sensor 64.ｍ１ and the pinion angle θ calculated by the pinion angle calculation unit 61. ｐ The axial force calculation unit 72 takes in the vehicle speed V and the current I of the motor 21. ｍ and pinion angle θ ｐ Based on the above, the axial force acting on the steered shaft 15 is calculated, and the calculated axial force is converted into a torque applied to the steering shaft 13, thereby obtaining a torque conversion value T ａｆ Calculate the following.

[0026] The target steering torque calculation unit 73 calculates the input torque T ｉｎ ＊ and the torque conversion value T calculated by the axial force calculation unit 72. ａｆ The target steering torque calculation unit 73 takes in the input torque T ｉｎ ＊ and torque equivalent value T ａｆ Based on this, the target steering torque T ｈ ＊ The target steering torque T ｈ ＊ is the steering torque T applied to the steering wheel 11 ｈ The target value of the input torque T ｉｎ ＊ The larger the absolute value of the target steering torque T ｈ ＊ The absolute value of becomes larger.

[0027] The torque feedback control unit 74 receives the steering torque T detected through the torque sensor 51. ｈ and the target steering torque T calculated by the target steering torque calculation unit 73. ｈ ＊ The torque feedback control unit 74 receives the steering torque T detected through the torque sensor 51. ｈ is the target steering torque T ｈ ＊ The steering torque T ｈ By executing the feedback control of the first assist torque T １ ＊ Calculate the following.

[0028] The target angle calculation unit 75 calculates the target angle based on the vehicle speed V detected by the vehicle speed sensor 52 and the steering torque T detected by the torque sensor 51. ｈ and the torque conversion value T calculated by the axial force calculation unit 72. ａｆ and the first assist torque T calculated by the torque feedback control unit 74. １ ＊ The target angle calculation unit 75 takes in the vehicle window V, steering torque T ｈ , torque equivalent value T ａｆ , and the first assist torque T １ ＊ Based on this, the target pinion angle θ ｐ ＊ Calculate the target pinion angle θ ｐ ＊ is the target value of the rotation angle of the pinion shaft 23.

[0029] The target angle calculation unit 75 calculates the target pinion angle θ using a model expressed by the following equation (A), for example. ｐ ＊ The model calculates the first assist torque T １ ＊ The ideal pinion angle θ when a torque corresponding to ｐ This is a model of the above.

[0030] T １ ＊ = J θ ｐ ＊ ''+C・θ ｐ ＊ '+K・θ ｐ ＊ ...(A) where "J" is an inertia coefficient that models the moment of inertia of the EPS 10. "C" is a viscosity coefficient that models the friction of the EPS 10. "K" is a spring coefficient that models the specifications of the suspension and wheel alignment of the vehicle on which the EPS 10 is mounted, assuming them as springs. The inertia coefficient J, viscosity coefficient C, and spring coefficient K are values ​​that correspond to the vehicle speed V detected by the vehicle speed sensor 52. "θ ｐ ＊ '' is the target pinion angle θ ｐ ＊is the second time derivative of θ ｐ ＊ ' is the target pinion angle θ ｐ ＊ The symbol "·" in equation (A) indicates multiplication.

[0031] The angle feedback control unit 76 controls the target pinion angle θ calculated by the target angle calculation unit 75. ｐ ＊ and the pinion angle θ calculated by the pinion angle calculation unit 61. ｐ The angle feedback control unit 76 receives the pinion angle θ calculated by the pinion angle calculation unit 61. ｐ is the target pinion angle θ ｐ ＊ The pinion angle θ ｐ By executing the feedback control of the second assist torque T ２ ＊ Calculate the following.

[0032] The second adder 77 calculates the first assist torque T １ ＊ and the second assist torque T calculated by the angle feedback control unit 76. ２ ＊ By adding the above, the assist command value T ＊ Assist command value T ＊ The motor 21 is supplied with a current according to the assist command value T ＊ A torque corresponding to the

[0033] <Regarding Occupant's Head Swing> Occupant's head jerk may increase due to steering of the steering wheel 11 by the driver or steering intervention by the host control device 500. Jerk is the rate of change of acceleration with respect to time, i.e., the time derivative of acceleration. Jerk is one of the indicators of human body movement that affects the ride comfort or discomfort of vehicle occupants. In the following description, an indicator of human body movement is referred to as a human body movement indicator. For example, when a vehicle travels on a curved road, centrifugal force causes the occupant's head or upper body to swing, resulting in significant lateral movement of the head. The lateral direction refers to the left or right of the vehicle's traveling direction. For this reason, jerk due to lateral movement of the head is likely to increase. If the jerk due to lateral movement of the head is large, the occupant may feel discomfort. Therefore, in this embodiment, the command value calculation unit 62 has the following configuration.

[0034] 3, the command value calculation unit 62 has a jerk suppression processing unit 80. The jerk suppression processing unit 80 is provided in the command value calculation unit 62 on a calculation path between the target angle calculation unit 75 and the angle feedback control unit 76.

[0035] 4, the jerk suppression processing unit 80 includes an arbitration processing unit 80A, an estimation processing unit 80B, a determination processing unit 80C, and a correction processing unit 80D. The arbitration processing unit 80A calculates the target pinion angle θ calculated by the target angle calculation unit 75. ｐ ＊ and a command angle θ calculated by the upper control device 500. ＊ The arbitration processing unit 80A takes in the target pinion angle θ ｐ ＊ and command angle θ ＊ Command angle θ ＊ is the current pinion angle θ ｐ When the additional angle is the additional angle to be added to the current target pinion angle θ ｐ ＊ command angle θ ＊ By adding the above, the target pinion angle after arbitration θ ｐ_ｍｅｄ ＊ Calculate the command angle θ＊ is the current pinion angle θ ｐ When the command angle θ is a substitute angle that replaces the command angle θ ＊ The target pinion angle θ after arbitration ｐ_ｍｅｄ ＊ When the driving assistance function or the automatic driving function is turned off, that is, when the upper control device 500 sets the command angle θ ＊ When is not calculated, the current pinion angle θ ｐ The target pinion angle θ after arbitration ｐ_ｍｅｄ ＊ Set as.

[0036] The estimation processing unit 80B estimates the target pinion angle θ after arbitration calculated by the arbitration processing unit 80A. ｐ_ｍｅｄ ＊ Target pinion angle θ ｐ_ｍｅｄ ＊ is one of the state variables of the vehicle. The estimation processing unit 80B estimates the post-arbitration target pinion angle θ ｐ_ｍｅｄ ＊ The estimated jerk value ζ is calculated using a human body behavior model based on the target pinion angle θ after arbitration. ｐ_ｍｅｄ ＊ The human body behavior model is, for example, a model in which the behavior of a passenger seated in a vehicle seat is modeled as an equivalent double inverted pendulum.

[0037] The determination processing unit 80C receives the estimated jerk value ζ calculated by the estimation processing unit 80B. Based on the estimated jerk value ζ, the determination processing unit 80C determines whether the jerk caused by the lateral movement of the occupant's head has reached a level that requires suppression. The determination processing unit 80C compares the estimated jerk value ζ with a threshold value. The threshold value is set based on a jerk that is considered to be likely to cause discomfort to the occupant.

[0038] The determination processing unit 80C determines that the jerk has not reached a level that should be suppressed when the jerk estimated value ζ is less than a threshold value. The determination processing unit 80C determines that the jerk has reached a level that should be suppressed when the jerk estimated value ζ is equal to or greater than a threshold value. The determination processing unit 80C switches the filter function of the correction processing unit 80D between on and off depending on the determination result of whether the jerk has reached a level that should be suppressed.

[0039] For example, the determination processing unit 80C sets a coefficient α for the correction processing unit 80D depending on the determination result of whether the jerk has reached a level that should be suppressed. When the determination processing unit 80C determines that the jerk has not reached a level that should be suppressed, the determination processing unit 80C sets the coefficient α to "0." When the determination processing unit 80C determines that the jerk has reached a level that should be suppressed, the determination processing unit 80C sets the coefficient α to "1."

[0040] The correction processing unit 80D calculates the target pinion angle θ after arbitration calculated by the arbitration processing unit 80A. ｐ_ｍｅｄ ＊ and a coefficient α set by the determination processing unit 80C. The correction processing unit 80D calculates the adjusted target pinion angle θ ｐ_ｍｅｄ ＊ The correction processing unit 80D has a filter for signal processing. The correction processing unit 80D corrects the adjusted target pinion angle θ ｐ_ｍｅｄ ＊ The filtering process is performed on the target pinion angle θ after arbitration. ｐ_ｍｅｄ ＊ This is a process for removing frequency components that are thought to be likely to shake the occupant's head.

[0041] The correction processing unit 80D switches the filter function between ON and OFF based on the coefficient α. That is, the correction processing unit 80D calculates the final target pinion angle θ based on the following equation (1). ｐ_ｆｉｎ ＊ Determine the final target pinion angle θ ｐ_ｆｉｎ ＊ is the pinion angle θ ｐ is the final target pinion angle used for feedback control.

[0042] θ ｐ_ｆｉｎ ＊ = θ ｐ_ｍｅｄ ＊ (1-α) + θ ｐ_ｆｉｌ ＊ ・α … (1) However, "θ ｐ_ｆｉｌ ＊ " is the target pinion angle θ after arbitration ｐ_ｍｅｄ ＊ is the corrected target pinion angle obtained by filtering the target pinion angle. The symbol "·" in equation (1) indicates multiplication.

[0043] When the coefficient α is “0”, that is, when the jerk has not reached the level at which it should be suppressed, the correction processing unit 80D calculates the target pinion angle θ after mediation. ｐ_ｍｅｄ ＊ The final target pinion angle θ ｐ_ｆｉｎ ＊ The target pinion angle θ after filtering is set as follows: ｐ_ｆｉｌ ＊ Not using it 100% means turning off the filter function.

[0044] When the coefficient α is “1”, that is, when the jerk has reached a level at which it should be suppressed, the correction processing unit 80D calculates the target pinion angle θ after filtering. ｐ_ｆｉｌ ＊ The final target pinion angle θ ｐ_ｆｉｎ ＊ The target pinion angle θ after filtering is set as follows: ｐ_ｆｉｌ ＊ Using 100% of the bandwidth means turning on the filter function.

[0045] The angle feedback control unit 76 calculates the final target pinion angle θ ｐ_ｆｉｎ ＊ Using the pinion angle θ ｐ The feedback control is performed as follows. <Effects of the embodiment> The present embodiment has the following effects.

[0046] (1) When the determination processing unit 80C determines that the human body motion index that affects the ride comfort or discomfort of the vehicle occupants has reached a level that should be suppressed, the correction processing unit 80D adjusts the adjusted target pinion angle θ so that the human body motion index is suppressed. ｐ_ｍｅｄ＊ By correcting the final target pinion angle θ ｐ_ｆｉｎ ＊ Therefore, the final target pinion angle θ ｐ_ｆｉｎ ＊ Based on the pinion angle θ ｐ By carrying out the feedback control, the human body motion index that affects the ride comfort or discomfort of the vehicle occupants is suppressed. Therefore, the discomfort of the occupants is reduced, and more appropriate comfort can be ensured for the occupants. The ride comfort of the vehicle is also ensured.

[0047] (2) The human body motion index is, for example, jerk caused by lateral movement of the head of a vehicle occupant. Jerk is one of the human body motion indexes that affect the ride comfort or discomfort of a vehicle occupant. By suppressing the jerk caused by lateral movement of the head of a vehicle occupant, the discomfort of the occupant is reduced, thereby ensuring more appropriate comfort for the occupant.

[0048] (3) The estimation processing unit 80C calculates an estimated value of a human body motion index that affects the riding comfort or discomfort of the vehicle occupants based on the state variables of the vehicle. The state variables are the adjusted target pinion angle θ ｐ_ｍｅｄ ＊ The estimated human body motion index is the estimated jerk value ζ. The jerk caused by the lateral movement of the occupant's head is affected by the turning motion of the vehicle. Therefore, the target pinion angle θ after adjustment ｐ_ｍｅｄ ＊ It is preferable to calculate the jerk estimate ζ based on:

[0049] (4) The correction processing unit 80D calculates the adjusted target pinion angle θ ｐ_ｍｅｄ ＊ By filtering the final target pinion angle θ ｐ_ｆｉｎ ＊ The filtering process calculates the target pinion angle θ after arbitration. ｐ_ｍｅｄ ＊ This is a process for removing frequency components that are likely to shake the occupant's head from the final target pinion angle θ ｐ_ｆｉｎ ＊ Based on the pinion angle θ ｐBy performing the feedback control, the jerk caused by the lateral movement of the occupant's head is appropriately suppressed.

[0050] (5) The estimation processing unit 80B calculates an estimated value of the human body motion index using a human body behavior model that models the behavior of an occupant seated in a vehicle seat. The estimated value of the human body motion index is, for example, an estimated jerk value ζ. By using the human body behavior model, the estimated value of the human body motion index can be easily obtained.

[0051] (6) The human body behavior model is used to calculate an estimated value of a human body motion index, which is used to determine whether a human body motion index that affects the ride comfort or discomfort of vehicle occupants has reached a level that requires suppression. The human body motion index is a jerk caused by the lateral movement of the occupant's head, and the estimated value of the human body motion index is a jerk estimated value ζ. Therefore, unlike when the human body behavior model is directly used for steering control, modeling errors do not affect the process of suppressing a human body motion index that affects the ride comfort or discomfort of vehicle occupants.

[0052] (7) If the determination processing unit 80C does not determine that the human body motion index has reached a level that requires suppression, the correction processing unit 80D adjusts the target pinion angle θ after mediation. ｐ_ｍｅｄ ＊ In other words, the correction processing unit 80D turns off the filter function. When the determination processing unit 80C determines that the human body motion index has reached a level at which it should be suppressed, the correction processing unit 80D does not perform filtering on the adjusted target pinion angle θ ｐ_ｍｅｄ ＊ That is, the correction processing unit 80D turns on the filter function. Therefore, if the human body motion index does not reach a level at which it should be suppressed, the adjusted target pinion angle θ ｐ_ｍｅｄ ＊ The original pinion angle θ based on ｐ When the human body motion index reaches a level at which it should be suppressed, the target pinion angle θ after adjustment is adjusted so that the human body motion index that affects the riding comfort or discomfort of the vehicle occupants is suppressed, with emphasis on the riding comfort. ｐ_ｍｅｄ ＊ can be corrected.

[0053] Other Embodiments This embodiment may be modified as follows: The correction processing unit 80D calculates the adjusted target pinion angle θ ｐ_ｍｅｄ ＊ The state where the correction is performed and the target pinion angle θ after adjustment ｐ_ｍｅｄ ＊ When switching between the state where the correction is not performed and the state where the correction is not performed, the target pinion angle θ after adjustment before and after correction ｐ_ｍｅｄ ＊ The target pinion angle θ after arbitration may be smoothly interpolated. ｐ_ｍｅｄ ＊ The state in which the correction is performed is a state in which the filter function is turned on, and the target pinion angle θ after arbitration ｐ_ｍｅｄ ＊ The state in which the correction is not performed is a state in which the filter function is turned off. ｐ_ｍｅｄ ＊ By interpolating the final target pinion angle θ ｐ_ｆｉｎ ＊ Therefore, when the filter function is switched on and off, the discontinuous change in the final target pinion angle θ ｐ_ｆｉｎ ＊ Sudden changes in the

[0054] The determination processing unit 80C may be configured to set the coefficient α in increments of, for example, 0.1 within a range from 0 (0%) to 1 (100%). When switching the filter function of the correction processing unit 80D from off to on, the determination processing unit 80C instantly switches the coefficient α from 0 to 1. Therefore, when the jerk estimation value ζ increases to or exceeds the threshold value, the filter function of the correction processing unit 80D can be immediately turned on. That is, the correction processing unit 80D calculates the post-arbitration target pinion angle θ ｐ_ｍｅｄ ＊ The target pinion angle θ after adjustment from the state without correction ｐ_ｍｅｄ ＊ When transitioning to a state where the correction of the final target pinion angle θ ｐ_ｆｉｎ ＊ The target pinion angle θ after adjustment before correction ｐ_ｍｅｄ ＊ to the corrected target pinion angle θｐ_ｆｉｌ ＊ Immediately switch to

[0055] In contrast, when switching the filter function of the correction processing unit 80D from on to off, the determination processing unit 80C gradually changes the coefficient α from "1" to "0" in increments of "0.1". ｐ_ｆｉｎ ＊ Target pinion angle θ after filtering ｐ_ｆｉｌ ＊ The distribution ratio of the adjusted target pinion angle θ ｐ_ｍｅｄ ＊ The target pinion angle θ after adjustment from the state where the correction is performed ｐ_ｍｅｄ ＊ When transitioning to a state where correction is not performed, the final target pinion angle θ ｐ_ｆｉｎ ＊ The corrected target pinion angle θ ｐ_ｆｉｌ ＊ Target pinion angle θ after adjustment before correction ｐ_ｍｅｄ ＊ Gradually switch to

[0056] Therefore, the final target pinion angle θ ｐ_ｆｉｎ ＊ is the target pinion angle θ after filtering ｐ_ｆｉｌ ＊ Target pinion angle θ after arbitration ｐ_ｍｅｄ ＊ The coefficient α is the filtered target pinion angle θ ｐ_ｆｉｌ ＊ is the final target pinion angle θ ｐ_ｆｉｎ ＊ This indicates the degree to which the

[0057] The behavior of an occupant in response to vehicle motion varies depending on the seat in which the occupant sits. Therefore, multiple human body behavior models may be constructed according to the position of the seat. The seats may include, for example, a driver's seat, a passenger seat, a right rear seat, and a left rear seat. In this case, the estimation processing unit 80B uses multiple human body behavior models to calculate an estimated head jerk value ζ for the occupant sitting in each seat. The determination processing unit 80C determines whether the jerk due to the lateral movement of the occupant's head has reached a level that should be suppressed, based on the largest jerk estimated value ζ among the multiple jerk estimated values ​​ζ calculated based on the multiple human body behavior models. In this way, the jerk of the occupant's head can be appropriately suppressed regardless of the seat in which the occupant sits.

[0058] The human body behavior model is not limited to the estimated jerk value ζ of the occupant's head, and may be any human body behavior model that outputs a human body motion index that affects the ride comfort or discomfort of the vehicle occupant in accordance with the input vehicle state variables. The determination processing unit 80C determines whether the jerk of the occupant's head has reached a level that requires suppression based on the human body motion index. Even in this case, the same effects as those in sections (1) to (7) of this embodiment can be obtained.

[0059] The correction processing unit 80D outputs the final target pinion angle θ ｐ_ｆｉｎ ＊ The target pinion angle after arbitration is θ ｐ_ｍｅｄ ＊ and the target pinion angle θ after filtering ｐ_ｆｉｌ ＊ However, the following may be done. That is, the correction processing unit 80D switches the filter function between on and off without using the above equation (1). The correction processing unit 80D switches the filter coefficient depending on the determination result by the determination processing unit 80C as to whether the jerk has reached a level that requires suppression. The filter coefficient is, for example, a coefficient string that is a collection of multiple coefficients. The frequency characteristics of the filter are determined by the filter coefficient.

[0060] The filter coefficients include a first coefficient sequence and a second coefficient sequence. The first coefficient sequence is a coefficient sequence for calculating a post-arbitration target pinion angle θ ｐ_ｍｅｄ ＊ The second coefficient sequence is a coefficient sequence for normal operation in which no processing is performed to remove frequency components that are thought to be likely to shake the occupant's head from the target pinion angle θ after arbitration. ｐ_ｍｅｄ ＊ This is a coefficient sequence used for correction, which performs processing to remove frequency components that are thought to be likely to shake the occupant's head.

[0061] When the coefficient α is "0", that is, when the jerk has not yet reached the level at which it should be suppressed, the correction processing unit 80D switches the filter coefficient to the first coefficient sequence. Switching the filter coefficient to the first coefficient sequence is equivalent to turning off the filter function. When the coefficient α is "1", that is, when the jerk has reached the level at which it should be suppressed, the correction processing unit 80D switches the filter coefficient to the second coefficient sequence. Switching the filter coefficient to the second coefficient sequence is equivalent to turning on the filter function. Even in this way, it is possible to obtain the same effects as those in sections (1) to (7) of this embodiment.

[0062] The correction processing unit 80D may disable the function of suppressing jerk of the occupant's head based on a command from the higher-level control device 500. The higher-level control device 500 generates a disabling command to disable the determination result of the determination processing unit 80 according to the running state of the vehicle. The determination result to be disabled is a determination result that the jerk has reached a level that requires suppression.

[0063] For example, when there is a risk of the vehicle colliding with an obstacle present in the traveling direction of the vehicle, the upper control device 500 generates a disable command. This is because the execution of emergency avoidance control for avoiding a collision between the vehicle and the obstacle is given priority over suppressing the jerk of the occupant's head. Furthermore, when there is a risk of the vehicle colliding with an obstacle, the upper control device 500 generates a command angle θ for moving the vehicle in a direction away from the obstacle. ＊ Calculate the following.

[0064] The determination processing unit 80 determines that the human body motion index has not reached a level at which it should be suppressed, regardless of the estimated value of the human body motion index that affects the ride comfort or discomfort of the vehicle occupants. Specifically, when the invalidation command is received, the determination processing unit 80C sets the coefficient α to "0" regardless of the estimated jerk value ζ. Therefore, regardless of the estimated jerk value ζ, the command angle θ for emergency avoidance is ＊ Final target pinion angle θ ｐ_ｆｉｎ ＊ Based on this, the pinion angle θ ｐ Therefore, a collision between the vehicle and the obstacle can be appropriately avoided.

[0065] When it is determined that the jerk of the occupant's head has reached a level that requires suppression, the determination processing unit 80C may generate a request signal to the host control device 500 requesting correction of the vehicle trajectory. The request signal includes a human body motion index, such as a jerk estimate value ζ. Based on the human body motion index included in the command from the determination processing unit 80C, the host control device 500 calculates a vehicle trajectory that will suppress the jerk of the occupant's head, and sets a command angle θ for driving the vehicle along the calculated trajectory. ＊ At this time, the host control device 500 calculates the final target pinion angle θ corrected by the correction processing unit 80D. ｐ_ｆｉｎ ＊ The target pinion angle θ ｐ ＊ The trajectory may be calculated taking into consideration the characteristics of the command angle θ ＊ Final target pinion angle θ ｐ_ｆｉｎ ＊ Pinion angle θ based on ｐ By this feedback control, the vehicle travels along the trajectory calculated by the host control device 500. This makes it possible to suppress jerk of the occupant's head.

[0066] The determination processing unit 80B may calculate the estimated jerk value ζ using a human body behavior model based on the acceleration of the vehicle, for example. The acceleration is one of the state variables of the vehicle. The estimated jerk value ζ is an estimate of the jerk caused by the forward and backward movement of the occupant's head in response to the acceleration of the vehicle. The acceleration is obtained by differentiating the vehicle speed V detected by the vehicle speed sensor 52 with respect to time. The filter coefficient is set to an appropriate value.

[0067] The estimation processing unit 80B may calculate an estimated value of a human body motion index that affects the ride comfort or discomfort of the vehicle occupant without using a human body motion model. For example, the vehicle is equipped with a camera that captures the human body motion of the occupant. The camera generates captured data of the human body motion. The estimation processing unit 80B imports the captured data and calculates an estimated value of a human body motion index that affects the ride comfort or discomfort of the vehicle occupant based on the imported captured data. The human body motion index includes jerk of the occupant's head. The determination processing unit 80C may determine whether the human body motion index has reached a level that should be suppressed based on the estimated value of the human body motion index calculated by the estimation processing unit 80B. The determination processing unit 80C sets a coefficient α for the correction processing unit 80D depending on the determination result of whether the human body motion index has reached a level that should be suppressed. The filter coefficient is set to an appropriate value depending on the human body motion index to be suppressed.

[0068] The control device 50 may be applied to a steer-by-wire steering device. In this steering device, power transmission between the steering wheel 11 and the steered wheels 12 is separated. In this case, the motor 21 functions, for example, as a steering motor that generates a steering force. The steering force is a force for steering the steered wheels 12.

Claims

1. A steering control device configured to control a motor that drives a steering device that steers the steered wheels of a vehicle, comprising: an angle feedback control unit configured to execute feedback control to make an actual angle follow a target rotation angle of a shaft that rotates in conjunction with the steering operation of the steered wheels; an estimation processing unit configured to calculate an estimate of a human body motion index that indicates human body movement that affects the ride comfort or discomfort of an occupant of the vehicle, based on state variables of the vehicle; a judgment processing unit configured to judge whether the human body motion index has reached a level that should be suppressed, based on the estimate of the human body motion index calculated by the estimation processing unit; and a correction processing unit configured to correct the target rotation angle so that the human body motion index is suppressed, when the judgment processing unit judges that the human body motion index has reached a level that should be suppressed.

2. A steering control device as described in claim 1, wherein the estimation processing unit is configured to calculate an estimated value of the human body motion index using a human body behavior model that models the behavior of an occupant seated in a seat of the vehicle.

3. A steering control device as described in claim 2, wherein the human body behavior model includes a plurality of human body behavior models provided according to the position of the seats in the vehicle, the estimated value of the human body movement index includes a plurality of estimated values ​​of the human body movement index calculated using a plurality of the human body behavior models, and the judgment processing unit is configured to judge whether the human body movement index has reached a level at which it should be suppressed based on the largest estimated value of the human body movement index among the plurality of estimated values ​​of the human body movement index.

4. A steering control device as claimed in any one of claims 1 to 3, wherein the human body motion index is a jerk caused by lateral movement of the head of an occupant of the vehicle.

5. A steering control device according to any one of claims 1 to 3, wherein the state variable is a target rotation angle of the shaft.

6. A steering control device according to any one of claims 1 to 3, wherein the correction processing unit is configured to correct the target rotation angle by performing a filter process on the target rotation angle.

7. A steering control device as described in claim 6, wherein the correction processing unit is configured not to perform the filtering process when the judgment processing unit does not determine that the human body motion index has reached a degree that should be suppressed, and to perform the filtering process when the judgment processing unit determines that the human body motion index has reached a degree that should be suppressed.

8. A steering control device as described in claim 6, wherein the correction processing unit is configured to switch the filter coefficients of the filter processing between a first coefficient sequence when the filter processing is not performed and a second coefficient sequence when the filter processing is performed, depending on the judgment result of the judgment processing unit.

9. A steering control device as described in any one of claims 1 to 3, wherein the correction processing unit is configured to smoothly interpolate the target rotation angle before and after correction when switching between a state in which the target rotation angle is corrected and a state in which the target rotation angle is not corrected.

10. A steering control device as described in any one of claims 1 to 3, wherein the correction processing unit is configured to, when transitioning from a state in which the target rotation angle is not corrected to a state in which the target rotation angle is corrected, immediately switch the target rotation angle from the target rotation angle before correction to the target rotation angle after correction, and when transitioning from a state in which the target rotation angle is corrected to a state in which the target rotation angle is not corrected, gradually switch the target rotation angle from the target rotation angle after correction to the target rotation angle before correction.

11. A steering control device as described in any one of claims 1 to 3, wherein the judgment processing unit is configured to judge that the human body motion index has not reached a level at which it should be suppressed, regardless of the estimated value of the human body motion index, when an invalidation command is received from an on-board higher-level control device.

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