Steering system

Abstract

The goal is to ensure that the reaction force is controlled effectively. [Solution] This steering system is a steer-by-wire type equipped with a reaction force device and a steering device. In this steering system, the reaction force is controlled based on the steering angle deviation, which is the difference between the target steering angle and the actual steering angle. Furthermore, the steering angle deviation is a value that has undergone phase adjustment. As a result, the delay in the effect of changes in the steering angle deviation on the reaction force can be suppressed, and the driver can be properly informed of the steering state of the wheels through the reaction force applied to the steering control member. This allows for effective control of the reaction force.

Description

Technical Field

[0006] , ,

[0005] , , , ,

[0001] The present invention relates to a steering system provided in a vehicle.

Background Art

[0002] Patent Document 1 describes a steer-by-wire type steering system including a reaction force device and a steering device. In the reaction force device of this steering system, the reaction force motor is controlled so that the target value of the operating torque, which is the reaction force torque, is realized. Further, the operating torque is obtained based on the steering angle deviation, which is the difference between the target steering angle and the actual steering angle, and the target value of the operating torque is determined by performing a phase advance process on the obtained operating torque.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem of the present invention is to enable good control of the reaction force.

Means for Solving the Problems

[0005] This steering system is of a steer-by-wire type including a reaction force device and a steering device. In this steering system, the reaction force is controlled based on the phase-adjusted deviation, which is the steering angle deviation subjected to phase adjustment. As a result, it is possible to suppress the influence delay of the change in the steering angle deviation on the reaction force, and it is possible to properly inform the driver of the steering state of the wheels through the reaction force applied to the steering operation member. Thus, good control of the reaction force can be achieved. <000003​​As described above, in the steering system described in Patent Document 1, the operating torque is obtained based on the steering angle deviation, and the target value of the operating torque is determined by performing phase lead compensation on the obtained operating torque. In contrast, in the steering system according to the present invention, the target value of the reaction force is determined based on the phase-adjusted deviation. Thus, in the steering system according to the present invention, since the target value of the reaction force is determined based on the phase-adjusted steering angle deviation, it is possible to quickly reflect changes in the steering angle deviation in the target value of the reaction force compared to the steering system described in Patent Document 1, and to effectively suppress the delay in the change of the target value of the reaction force in response to changes in the steering angle deviation. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram conceptually illustrates a steering system according to one embodiment of the present invention. [Figure 2] This diagram conceptually shows the steering angle control unit and its surrounding area, which are key components of the steering system described above. [Figure 3] This diagram conceptually shows the reaction force control unit and its surrounding area, which are part of the steering system described above. [Figure 4] This diagram conceptually shows the steering drive circuit for the steering system described above. [Modes for carrying out the invention]

[0008] A steering system, which is one embodiment of the present invention, will be described below with reference to the drawings.

[0009] This steering system includes a reaction force device 10 and a steering device 12. The reaction force device 10 and the steering device 12 are mechanically independent of each other, in other words, mechanically isolated. This steering system is of the steer-by-wire type.

[0010] The reaction force device 10 includes a steering control member 20, a reaction force transmission mechanism 22, a reaction force actuator 26, etc. The reaction force device 10 transmits the reaction force to the driver via the steering control member 20. The steering control member 20 is operable by the driver and can be a rotatable steering wheel, a joystick that can move back and forth linearly or curved, etc. In this embodiment, a rotatable steering wheel is used as the steering control member 20.

[0011] An input shaft 24 is connected to the steering wheel 20, and a reaction force transmission mechanism 22 is provided on the input shaft 24. The reaction force transmission mechanism 22 can, for example, have multiple gears. A reaction force actuator 26 is connected to the reaction force transmission mechanism 22. The reaction force actuator 26 includes a reaction force motor, but may also include a reduction gear in addition to the reaction force motor. The reaction force torque, which is the output torque of the reaction force actuator 26, is transmitted to the input shaft 24 via multiple gears and then to the steering wheel 20. An operating angle sensor 28, which acts as an operating amount sensor, is attached to the input shaft 24. The operating angle sensor 28 detects the amount of operation of the steering operating member, that is, the amount of operation from the neutral position, and in this embodiment, it detects the operating angle, which is the rotation angle of the steering wheel 20 from the neutral position.

[0012] The steering device 12 steers the left and right steering wheels. The left and right steering wheels can be, for example, the left and right front wheels FW1 and FW2. In this embodiment, the steering device 12 is a rack and pinion type and includes a steering actuator 30, a steering force transmission mechanism 32, an output shaft 33 which is the steering output shaft, a pinion gear 34, a rack bar 35, etc. The steering actuator 30 includes a steering motor, but may also include a reduction gear in addition to the steering motor. The rack bar 35 is provided extending in the width direction of the vehicle as its axial direction. The pinion gear 34 is screwed onto the rack bar 35.

[0013] The steering force transmission mechanism 32 transmits the driving force of the steering actuator 30 to the output shaft 33, causing the output shaft 33 to rotate in accordance with the rotation of the steering actuator 30. The steering force transmission mechanism 32 can, for example, have various gears (e.g., a planetary gear mechanism). The driving force of the steering actuator 30 is transmitted to the steering wheels FW1 and FW2 via the steering force transmission mechanism 32, the output shaft 33, the pinion gear 34, and the rack bar 35. The rotation of the pinion gear 34 displaces the rack bar 35 in the axial direction, and the steering wheels FW1 and FW2 steer left and right in accordance with the axial displacement of the rack bar 35. A steering angle sensor 38 is attached to the output shaft 33. The steering angle sensor 38 detects the rotation angle of the output shaft 33 from the neutral position. Based on the rotation angle of the output shaft 33, the actual steering angle δm, which is the actual steering angle of the left and right steering wheels FW1 and FW2, can be obtained.

[0014] The steering angle sensor can be configured to detect the displacement of the rack bar 35 from its neutral position. The neutral position is the position when the vehicle is in a straight line.

[0015] Furthermore, in the steering force transmission mechanism 32, the meshing configuration of the various gears can be appropriately changed, allowing the rotation transmitted from the steering actuator 30 to be appropriately decelerated and transmitted to the steering output shaft 33. This makes it possible to continuously change the steering gear ratio when steering the steering wheels FW1 and FW2. The steering gear ratio is the transmission ratio of the operating angle of the steering wheel 20 to the steering wheels (steering angle / operating angle).

[0016] This steering system is equipped with a computer-based control device 39. The control device 39 includes a reaction force control unit 40, a steering angle control unit 42, etc. The reaction force control unit 40 and the steering angle control unit 42 are connected to each other so as to be able to communicate via an L-CAN (Local Controller area Network) 44, which serves as a means of communication.

[0017] The reaction force control unit 40 controls the reaction force actuator 26. The reaction force control unit 40 is connected to the reaction force actuator 26 via a drive circuit (sometimes referred to as the operating-side drive circuit) 52, as well as to an operating angle sensor 28, a current sensor 54, and the like. The current sensor 54 is provided in the drive circuit 52 and detects the current flowing through the reaction force actuator 26. The reaction force actuator 26 is controlled so that the reaction force torque (operating torque) corresponding to the reaction force applied to the steering wheel 20 approaches the target value of the operating torque. Hereinafter, the target value of the operating torque will be referred to as the target operating torque.

[0018] The steering angle control unit 42 controls the steering actuator 30. The steering actuator 30 is connected to the steering angle control unit 42 via a steering drive circuit 62, which is a drive circuit, and the steering angle sensor 38, current sensor 64, vehicle speed sensor 74, etc. are also connected to the steering angle control unit 42. The current sensor 64 detects the actual current, which is the current flowing through the steering actuator 30. The vehicle speed sensor 74 detects the vehicle's speed. The steering actuator 30 is controlled so that the actual steering angle δm of the steering wheels FW1 and FW2 approaches the target steering angle δt, which is the target value of the steering angle. The target steering angle δt is the target steering angle in the steering control of the steering wheels FW1 and FW2, and can also be called the steering control target steering angle δt. The target steering angle δt will be described later.

[0019] Note that the steering angle and rudder angle are expressed with the neutral position set to "0," and one of the left-right rotation angles is represented as a positive value, while the other is represented as a negative value.

[0020] In this steering system, the steering states of the steered wheels FW1 and FW2 are transmitted to the driver as reaction forces via the steering wheel 20. The steering states of the steered wheels FW1 and FW2 are determined by the states of the steered wheels FW1 and FW2, the state of the steering device 12, and the like. The states of the steered wheels FW1 and FW2 include the state of the road surface with which the steered wheels FW1 and FW2 are in contact, the state of the road, and the like. For example, when the friction coefficient of the road surface with which the steered wheels FW1 and FW2 are in contact is low, and neither of the steered wheels FW1 and FW2 hits an obstacle such as a curb, and the steering device 12 is normal, etc., it is considered that the actual steering angle δm follows the target steering angle δt for steering well. This is because when the friction coefficient is low, the steered wheels FW1 and FW2 are easier to steer than when it is high. In this case, it is considered that the steering control deviation Da, which is the deviation between the actual steering angle δm and the target steering angle δt for steering, is small. Therefore, in order to inform the driver of the steering states of the steered wheels FW1 and FW2, it is considered that there is little need to apply a large reaction force. Hereinafter, a state in which the actual steering angle δm follows the target steering angle δt for steering well may be simply referred to as a state with good followability.

[0021] On the other hand, for example, when the friction coefficient of the road surface with which the steered wheels FW1 and FW2 are in contact is high, it is considered that the steered wheels FW1 and FW2 are difficult to steer following the target steering angle δt for steering. Also, when at least one of the steered wheels FW1 and FW2 hits an obstacle such as a curb, or when the steering device 12 is in an abnormal state and there is an abnormality in the control of the steering angle, it is considered that the steered wheels FW1 and FW2 become difficult to steer following the target steering angle δt for steering. In these cases, the followability is poor, and the steering control deviation Da tends to be large. Therefore, it is desirable to apply a large reaction force to inform the driver of the steering states of the steered wheels FW1 and FW2.

[0022] In a conventional steering system, a steering angle conversion value, which is a value obtained by converting the actual steering angle δm, which is the steering angle detected by the steering angle sensor 38, into a steering angle, is acquired, and a steering side deviation, which is the difference between the steering angle (which can be referred to as the steering angle) detected by the operation angle sensor 28 and the steering angle conversion value, is acquired. Then, a target operation torque is acquired according to the steering side deviation, and the reaction force actuator 26 is controlled. Therefore, it was possible to transmit the steering state of the steering wheels FW1 and FW2 to the driver well. However, since the process for obtaining the steering angle conversion value is complicated, it has been desired to perform reaction force control without using the steering angle conversion value.

[0023] On the other hand, it is conceivable that a target operation torque is acquired based on a steering control deviation Da, which is the difference between the target steering angle δt for steering and the actual steering angle δm, and reaction force control is performed. However, the reaction force is delayed with respect to the operation of the driver's steering wheel 20, and it has been difficult to promptly transmit the steering state of the steering wheels FW1 and FW2 to the driver.

[0024] That is, in the steering control unit 42, a target steering angle δt for steering is acquired based on the control operation angle θ acquired in the reaction force control unit 40, the steering actuator 30 is controlled, and the steering wheels FW1 and FW2 are steered. Therefore, the deviation between the target steering angle δt for steering and the actual steering angle δm detected by the steering angle sensor 38 is usually delayed with respect to the operation of the steering wheel 20. Thus, when the control of the reaction force actuator 26 based on the steering control deviation Da is delayed with respect to the operation of the steering wheel 20, it becomes difficult to transmit the steering state of the steering wheels FW1 and FW2 to the driver well (promptly).

[0025] Therefore, in this embodiment, the target operating torque is determined based on the phase-adjusted deviation Ds, which is the steering angle deviation after phase adjustment, and the reaction force actuator 26 is controlled accordingly. As a result, lag is suppressed, and the steering state of the steering wheels FW1 and FW2 can be quickly transmitted to the driver via the steering wheel 20. In this embodiment, phase adjustment mainly refers to adjustments that suppress lag. For example, this includes advancing the phase, performing phase advance compensation, and considering the differential value. Determining the target operating torque by obtaining the phase-adjusted deviation Ds and controlling the reaction force actuator 26 in this manner is called deviation compensation control. Alternatively, obtaining the target operating torque by obtaining the phase-adjusted deviation Ds can also be called deviation compensation control.

[0026] The deviation compensation control will be explained below based on Figure 2-4.

[0027] As shown in Figure 3, the reaction force control unit 40 receives input such as the operating angle θm detected by the operating angle sensor 28, and the control operating angle θ is obtained based on the detected operating angle θm. For example, the control operating angle θm can be obtained by limiting the output of the operating angle θm detected by the operating angle sensor 28. Output limiting can be used, for example, to suppress sudden changes in the detected value θm or to exclude abnormal values. The control operating angle θ is supplied to the steering control unit 42 via the L-CAN 44.

[0028] As shown in Figure 2, the steering angle control unit 42 receives input such as the control operation angle θ, vehicle speed v, and actual steering angle δm. The steering angle control unit 42 acquires the target steering angle δt, which is used for steering angle control of the steering wheels FW1 and FW2, based on the control operation angle θ, vehicle speed v, etc., and controls the steering actuator 30 based on the target steering angle δt.

[0029] Furthermore, in the steering angle control unit 42, the phase-adjusted target steering angle δh is obtained by performing a phase adjustment on the target steering angle δt, and the phase-adjusted actual steering angle δmh is obtained by performing a phase adjustment on the actual steering angle δm. Then, the steering angle deviation Ds is obtained based on the phase-adjusted target steering angle δh and the phase-adjusted actual steering angle δmh. The steering angle deviation Ds is an example of a phase-adjusted deviation, which is a steering angle deviation that has undergone phase adjustment. The phase-adjusted deviation Ds is supplied to the reaction force control unit 40.

[0030] In VG (Variable gear ratio) determination B1, the steering gear ratio is obtained based on the vehicle speed v, and the target steering angle is provisionally obtained based on the control operation angle θ and the steering gear ratio. This VG determination B1 is referred to as process B1, and the target steering angle provisionally obtained in process B1 is referred to as the first provisional target steering angle δ1.

[0031] The steering gear ratio is set so that, for example, the steering wheels FW1 and FW2 turn quickly when the vehicle speed v is low, and slowly when the vehicle speed v is high. For example, the steering gear ratio can be set to be larger when the vehicle speed v is low than when it is high. The steering gear ratio is set so that abrupt changes in response to changes in vehicle speed v are suppressed.

[0032] In LPF processing B2, a cutoff frequency is obtained based on at least one of the vehicle speed v and the control angle θ, and an LPF (Low-Pass Filter) process determined by the cutoff frequency is performed on the first provisional target steering angle δ1. The value after LPF processing is called the second provisional target steering angle δ2. The cutoff frequency is obtained based on at least one of the vehicle speed v and the control angle θ. For example, when the vehicle speed v is large, the cutoff frequency is lower than when it is small, and when the absolute value of the control angle θ is large, the cutoff frequency is lower than when it is small.

[0033] In output compensation B3, the output is limited for the second provisional target steering angle δ2, and the third provisional target steering angle δ3 is obtained. For example, if the absolute value of the control operation angle θ becomes large while the vehicle is stopped (e.g., when turning the steering wheel while stationary), it may be difficult for the steering device 12 to achieve the target steering angle obtained for that operation angle. Therefore, if the absolute value of the operation angle becomes larger than the set value while the vehicle is stopped, the target steering angle is limited. For example, the absolute value of the target steering angle can be limited to a value corresponding to the set value of the operation angle, or it can be limited to a value obtained by multiplying the target steering angle by a setting ratio γ less than 1. However, there is little need to limit the target steering angle while the vehicle is in motion. Therefore, in output compensation B3, the target steering angle is adjusted so that the change in the target steering angle between when the vehicle is stopped and when it is in motion is mitigated.

[0034] In β control B4 (processing B4), the third provisional target steering angle δ3 is corrected based on the difference between the steering angle and the vehicle's direction of travel, and the fourth provisional target steering angle δ4 is obtained. For example, when straddling brakes, the steering angle is almost zero, and even if the driver wants to drive straight, the vehicle will turn towards the high-μ side due to the difference in road surface μ on the left and right sides. Therefore, it is desirable to steer the steering wheels towards the low-μ side. Taking this into consideration, the third provisional target steering angle δ3 is corrected. The same applies when the driver applies counter-steering when the vehicle is in an oversteer state.

[0035] In offset processing B5, abrupt changes in the fourth provisional target steering angle δ4 are suppressed, and the fifth provisional target steering angle δ5 is obtained. For example, if the change in the fourth provisional target steering angle δ4 becomes large, the fifth provisional target steering angle δ5 is determined to be the value before the abrupt change (previous value), and thereafter, it is determined so that the difference between the current value and the previous value gradually decreases.

[0036] In residual current reduction processing B6, residual current reduction processing is performed on the fifth provisional target steering angle δ5, and the sixth provisional target steering angle δ6 is obtained. For example, even if the driver stops operating the steering wheel 20 and takes their hands off the steering wheel 20, if the steering control deviation Da is not zero, current will flow to the steering actuator 30. To suppress this, for example, if it is determined that the vehicle is stopped and the hands are off the steering wheel, the sixth provisional target steering angle δ6 is obtained so as to reduce the current to the steering actuator 30. For example, the steering target steering angle δt, which is the sixth provisional target steering angle δ6, is obtained by correcting it to a value closer to the actual steering angle than the fifth provisional target steering angle δ5, and output to the steering drive circuit 62.

[0037] As shown in Figure 4, angle FB control C1 and current FB control C2 are performed in the steering drive circuit 62. In angle FB control C1, a target steering torque, which is the output of the steering actuator 30, is determined so that the actual steering angle δm approaches the target steering angle δt, and this is output to the current FB control unit C2. In the current FB control unit C2, a target current to the steering actuator 30 is determined so that the target steering torque is output, and the steering actuator 30 is controlled so that the actual current approaches the target current. The actual steering angles δm of the steering wheels FW1 and FW2 are detected by the steering angle sensor 38 and supplied to the steering angle control unit 42.

[0038] In response, the steering angle control unit 42 performs phase adjustment on the target steering angle δt and the actual steering angle δm. Phase adjustment includes processes to advance the phase and processes to suppress the lag. Phase adjustment is sometimes referred to as phase advance compensation. In this embodiment, the lag suppression process B8 and the phase advance filter processes B9 and B10 are executed.

[0039] Delay suppression process B8 is a process that suppresses the delay between the target steering angle δt and the control angle θ. This delay is thought to be caused by the execution of processes B1-B6. Then, a control amount (expressed as steering angle) corresponding to the delay caused by the execution of processes B1-B6 is obtained, and the target steering angle δt is corrected based on this control amount, etc. The corrected target steering angle δt is called the corrected target steering angle δ8.

[0040] In the delay suppression process B8, for example, the delay amount of the target steering angle can be obtained based on two or more of the first provisional target steering angle δ1 to the sixth provisional target steering angle δ6 output from each of processes B1 to B6, and the steering target steering angle δt can be corrected based on the control amount corresponding to the delay amount. Specifically, the control amount can be obtained based on the difference between the first provisional target steering angle δ1 and the sixth provisional target steering angle δ6, and the corrected target steering angle δ8 can be obtained by performing calculations such as adding the control amount to the steering target steering angle δt.

[0041] Furthermore, of the processes B1-B6, the majority of the delay occurs in the LPF process B2. Therefore, a control amount can be obtained based on the difference between the first provisional target steering angle δ1 and the second provisional target steering angle δ2, and the steering target steering angle δt can be corrected. Specifically, the corrected target steering angle δ8 can be obtained by adding the difference between the first provisional target steering angle δ1 and the second provisional target steering angle δ2 to the steering target steering angle δt.

[0042] Furthermore, before the target steering angle δt for steering is acquired, in addition to the LPF processing B2, a processing Bx that increases the delay may also be performed. In such cases, the control variable can be acquired based on the difference between the value after these delay-increasing processing B2 and Bx are performed and the value before these processing B2 and Bx are performed.

[0043] The phase-adjusted target steering angle δh is obtained by performing a phase-lead filtering process B9 on the corrected target steering angle δ8. Phase-lead filtering process B9 is a process that suppresses communication delay. The steering device 12 and the reaction device 10 are connected via L-CAN 44. The phase-lead filter is designed based on the communication delay (delay angle) between them. The phase-adjusted target steering angle δh can be aligned with the phase of the control operating angle θ.

[0044] In this embodiment, the actual steering angle δm is also phase-adjusted. The actual steering angle δm is processed in the phase-adjusted filter B10 to obtain the phase-adjusted actual steering angle δmh. The phase-adjusted filter in the phase-adjusted filter B10 is designed based on the communication delay, as in the case described above.

[0045] The processes described above, B8, B9, and B10, can be collectively referred to as phase adjustment and phase lead compensation, or one or more of these processes can be referred to as phase adjustment and phase lead compensation, respectively.

[0046] The difference between the phase-adjusted actual steering angle δmh and the phase-adjusted target steering angle δh is defined as the phase-adjusted deviation Ds, which is the steering angle deviation. The phase-adjusted deviation Ds is supplied to the reaction force device 10 via L-CAN 44. In the deviation compensation target operating torque calculation unit E1 of the reaction force control unit 40, the target operating torque, which is the target value of the reaction force torque, is obtained based on the phase-adjusted deviation Ds. The absolute value of the target operating torque is determined to be larger when the absolute value of the phase-adjusted deviation Ds is large compared to when it is small. As shown in Figure 3, the obtained target operating torque is output to the operating side drive circuit 52. The target operating torque can be called the deviation compensation target operating torque.

[0047] In this embodiment, the target operating torque is determined based on the phase-adjusted deviation Ds. Therefore, the delay in the change of the target operating torque in response to changes in the steering angle deviation can be effectively suppressed, and the steering state of the steering wheels FW1 and FW2 can be effectively transmitted to the driver as a reaction torque. When the steering wheels FW1 and FW2 follow the target steering angle δt determined by the steering wheel 20's operating angle, the driver can obtain a normal (light) steering feel. However, when the steering wheels FW1 and FW2 do not follow the target steering angle δt, the steering state of the steering wheels FW1 and FW2 can be quickly transmitted to the driver via the reaction force applied to the steering wheel 20.

[0048] Furthermore, when the vehicle is in autonomous driving mode, there is little need to communicate the steering state to the driver, because the steering wheel 20 is not being operated by the driver. Therefore, it is considered that there is little need to perform deviation compensation control.

[0049] In the above embodiment, a delay suppression process B8 and a phase lead filter process B9 were performed on the target steering angle δt to obtain a phase-adjusted target steering angle δh, and a phase lead filter process B10 was performed on the actual steering angle δm to obtain a phase-adjusted actual steering angle δmh, thereby obtaining a phase-adjusted deviation Ds. However, it is not necessarily required to perform all of these processes B8, B9, and B10; it is sufficient if at least one of these processes is performed.

[0050] Furthermore, it is possible to obtain a steering control deviation Da, which is the difference between the target steering angle δt and the actual steering angle δm, and then perform phase adjustment to suppress the delay in the steering control deviation Da so that a phase-adjusted deviation is obtained.

[0051] Furthermore, deviation compensation control can be configured to be executed when the steering control deviation Da is greater than a predetermined threshold Dath. This is because, in cases of poor tracking performance, the effects of reaction force control based on phase-adjusted deviation Ds can be greatly benefited.

[0052] Furthermore, the control device 39 can be configured such that the reaction force control unit 40 and the steering angle control unit 42 are integrated into one unit. In other words, reaction force control and steering angle control can be performed in the same control device. In that case, the phase lead filter processing B9 and 10 is not essential. By executing the delay suppression processing B8, the delay in the steering target steering angle δt relative to the operation of the steering wheel 20 can be suppressed.

[0053] Furthermore, the structure of the reaction force device 10 and the steering device 12 is not limited. For example, in the reaction force device 10, the operating angle sensor 28 can detect the operating angle of the steering wheel based on the rotation angle of the reaction force actuator. Alternatively, a torque sensor can be provided on the input shaft 24, and the operating angle can be detected based on the output value of the torque sensor. In the steering device 12, the rotation of the steering actuator can be converted into linear movement of the steering axis via a belt, pulley, and ball screw. Similarly, the steering angle sensor 38 can detect the steering angle based on the rotation angle of the steering actuator.

[0054] Furthermore, the logic for determining the target steering angle δt is not questioned.

[0055] Furthermore, the present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0056] 10: Reaction force device 12: Steering device 28: Operating angle sensor 30: Reaction force actuator 38: Steering angle sensor 40: Reaction force control unit 42: Steering angle control unit 74: Vehicle speed sensor Patentable invention

[0057] (1) A steer-by-wire steering system installed in a vehicle, A steering device for steering the wheels of the aforementioned vehicle, A reaction force device that applies a reaction force to a steering control member that can be operated by the driver, A control device for controlling the reaction force and Includes, A steering system in which the control device controls the reaction force based on a phase-adjusted deviation, which is the difference between the actual steering angle of the wheel and the target steering angle, which is the target value of the steering angle for the wheel, with the phase adjusted.

[0058] The phase-adjusted deviation can be, for example, the deviation obtained by performing phase adjustment on at least one of the actual steering angle and the target steering angle, and then using that phase-adjusted actual steering angle and target steering angle. Alternatively, the phase-adjusted deviation can be the value obtained by performing phase adjustment on the deviation between the actual steering angle before phase adjustment and the target steering angle before phase adjustment.

[0059] (2) The steering system according to item (1), wherein the control device performs a phase adjustment with respect to the target steering angle and acquires the phase-adjusted deviation in accordance with the phase of operation of the steering control member.

[0060] The phase of operation corresponds to the phase of the operating angle, which is the angle of rotation from the neutral position, when the steering control member is a rotary type such as a steering wheel. When the steering control member is a joystick or similar that moves back and forth in a generally linear or curved manner, the displacement from the neutral position corresponds to the phase.

[0061] (3) The control device includes a steering angle control unit that controls the steering device to control the steering angle of the wheels, and a reaction force control unit that controls the reaction force device to control the reaction force, The steering angle control unit and the reaction force control unit are connected to each other via a connection unit so as to be able to communicate with each other. The steering system according to (1) or (2), wherein the control device acquires the phase-adjusted deviation, which has undergone phase lead processing based on the communication delay via the connection.

[0062] For example, a phase-lead filter can be designed based on the phase angle of the communication delay at the connection point.

[0063] (4) The steering system according to any one of (1) to (3), wherein the control device obtains a target steering angle, which is a target steering angle, by performing at least one operation on the amount of operation of the steering operating member, and obtains a phase-adjusted target steering angle by performing phase adjustment on the target steering angle based on the delay that occurs in one or more of the at least one operations, and obtains the phase-adjusted deviation.

[0064] For example, in the steering control unit, the target steering angle is obtained by performing at least one process on the amount of operation of the steering control member, and in the control unit, the phase adjustment is performed based on the delay that occurs in one or more of the at least one processes to obtain the phase-adjusted target steering angle, which is the target steering angle, and the phase-adjusted deviation is obtained based on the phase-adjusted target steering angle.

Claims

1. A steer-by-wire steering system installed in a vehicle, A steering device for steering the wheels of the aforementioned vehicle, A reaction force device that applies a reaction force to a steering control member that can be operated by the driver, A control device for controlling the reaction force and Includes, A steering system in which the control device controls the reaction force based on a phase-adjusted deviation, which is the difference between the actual steering angle of the wheel and the target steering angle, which is the target value of the steering angle for the wheel, with the phase adjusted.

2. The steering system according to claim 1, wherein the control device performs a phase adjustment with respect to the target steering angle and acquires the phase-adjusted deviation in accordance with the phase of operation of the steering control member.

3. The control device includes a steering angle control unit that controls the steering device to control the steering angle of the wheels, and a reaction force control unit that controls the reaction force device to control the reaction force, The steering angle control unit and the reaction force control unit are connected via a connection unit so as to be able to communicate with each other. The steering system according to claim 1 or 2, wherein the control device acquires the phase-adjusted deviation, which has undergone phase lead processing based on the communication delay via the connection part.

4. The steering system according to claim 1 or 2, wherein the control device obtains a target steering angle, which is a target steering angle, by performing at least one process on the amount of operation of the steering operating member, and obtains a phase-adjusted target steering angle by performing a phase adjustment on the target steering angle based on a delay occurring in one or more of the at least one processes, and obtains the phase-adjusted deviation.

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