Vehicle steering device and vehicle steering device adjustment method

Abstract

To provide a vehicle steering device and an adjustment method for a vehicle steering device that can absorb a relative displacement between a steering angle and a turning angle.SOLUTION: A vehicle steering device includes: a reaction force motor that applies a steering reaction force to a handle; a turning motor that turns turning wheels in accordance with steering of the handle; and a control unit that controls the reaction force motor and the turning motor. The control unit controls the reaction force motor so as to steer the handle toward the right and thereby acquires the right side maximum steering angle, controls the reaction force motor so as to steer the handle toward the left and thereby acquires the left side maximum steering angle, and determines a middle point between the right side maximum steering angle and the left side maximum steering angle as a neutral position.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a vehicle steering system and a method for adjusting a vehicle steering system. [Background technology]

[0002] One vehicle steering system is a steer-by-wire (SBW) system in which a steering reaction force generating device (FFA: Force Feedback Actuator, steering mechanism) that is used by the driver to steer the vehicle and a tire steering device (RWA: Road Wheel Actuator, steering mechanism) that steers the vehicle are mechanically separated. In such an SBW system, the steering mechanism and the steering mechanism are electrically connected via a control unit (ECU: Electronic Control Unit), and the absolute angle of the steering angle sensor on the FFA side and the absolute angle of the steering angle sensor on the RWA side are synchronized to convert the driver's steering operation into tire movement.

[0003] In such a SBW vehicle steering system, if an abnormality occurs in the ECU, it may become impossible to determine the relative positions of the steering shaft and the wheel steering shaft.In order to resynchronize the angles of the steering shaft and the wheel steering shaft when the relative positions of the steering shaft and the wheel steering shaft become unknown, a technology has been disclosed in which the motor torque generated at the winding or loosening end of the power supply cable is detected to locate the motor rotation end, and the steering is automatically neutralized by returning the motor by a predetermined amount from this rotation limit (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-58745 Summary of the Invention [Problem to be solved by the invention]

[0005] However, with the technology disclosed in the above-mentioned prior art, there is a possibility that the power supply cable may break if excessive torque is applied to the power supply cable. Furthermore, if the neutral position is set by returning one rotation end by a predetermined amount, there is a possibility that a difference between the left and right rotation ends may occur due to product variations or product deterioration. Furthermore, if the driver touches the steering wheel during the neutral position setting process and the torque threshold is exceeded, this may be mistaken for the rotation end, causing the calculated neutral position to deviate from the actual neutral position, resulting in a relative discrepancy between the steering angle and the turning angle.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a method for detecting the neutral position of a steering wheel that is not easily affected by product variations and component deterioration, a vehicle running device equipped with said detection method, a vehicle steering device that can absorb the relative deviation between the steering angle and the turning angle, and a method for adjusting a vehicle steering device. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, a vehicle steering device according to one embodiment of the present invention comprises a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, wherein the control unit controls the reaction motor to steer the steering wheel to the right to obtain a maximum right-side steering angle, and controls the reaction motor to steer the steering wheel to the left to obtain a maximum left-side steering angle, and sets the midpoint between the maximum right-side steering angle and the maximum left-side steering angle as the neutral position of the steering wheel.

[0008] According to the above configuration, the neutral position of the steering wheel is corrected, and the relative deviation between the current steering angle position and the current turning angle position due to some physical force acting on the steering wheel can be absorbed.

[0009] As a desirable aspect of the vehicle steering device, it is preferable that the control unit acquires the right maximum steering angle or the left maximum steering angle when it detects any one of the following: the steering torque of the steering wheel has become equal to or greater than a predetermined torque threshold; the current value of the reaction force motor has become equal to or greater than a predetermined current threshold; and the angular velocity of the reaction force motor has become equal to or less than a predetermined angular velocity threshold.

[0010] As a result, if any one of the steering torque, the current value of the reaction force motor, and the angular velocity of the reaction force motor is normal, the steering wheel position correction process can be executed.

[0011] As a desirable aspect of the vehicle steering device, after acquiring the right maximum steering angle and the left maximum steering angle, it is preferable that the control unit controls the reaction motor until the current position of the steering wheel becomes equal to or greater than a predetermined target steering angle.

[0012] As a desirable aspect of the vehicle steering device, after acquiring the right maximum steering angle and the left maximum steering angle, it is preferable that the control unit controls the reaction motor until the current position of the steering wheel falls within a predetermined angle range including a predetermined target steering angle.

[0013] In order to achieve the above object, a vehicle steering device according to one aspect of the present invention includes a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, wherein the steering motor is controlled to steer the steered wheels to the right to obtain a right-side maximum steering angle, and the steering motor is controlled to steer the steered wheels to the left to obtain a left-side maximum steering angle, and the midpoint between the right-side maximum steering angle and the left-side maximum steering angle is set as a neutral position for the steered wheels.

[0014] According to the above configuration, the neutral position of the steered wheels is corrected, and the relative deviation between the current steering angle position and the current turning angle position due to some physical force acting on the steered wheels can be absorbed.

[0015] As a desirable aspect of the vehicle steering device, it is preferable that the control unit acquires the right maximum steering angle or the left maximum steering angle when it detects either that the current value of the steering motor has become equal to or greater than a predetermined current threshold, or that the angular velocity of the steering motor has become equal to or less than a predetermined angular velocity threshold.

[0016] As a result, if either the current value of the steering motor or the angular velocity of the steering motor is normal, the steered wheel position correction process can be executed.

[0017] As a desirable aspect of the vehicle steering device, after acquiring the right maximum steering angle and the left maximum steering angle, it is preferable that the control unit controls the steering motor until the current position of the steered wheels becomes equal to or greater than a predetermined target steering angle.

[0018] As a desirable aspect of the vehicle steering device, after acquiring the right maximum steering angle and the left maximum steering angle, it is preferable that the control unit controls the steering motor until the current position of the steered wheels falls within a predetermined angle range including a predetermined target steering angle.

[0019] In order to achieve the above object, a vehicle steering device according to one aspect of the present invention includes a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, wherein the control unit controls the reaction motor to steer the steering wheel rightward to obtain a maximum right steering angle, controls the reaction motor to steer the steering wheel leftward to obtain a maximum left steering angle, sets a midpoint between the maximum right steering angle and the maximum left steering angle as a neutral position of the steering wheel, controls the steering motor to steer the steered wheels rightward to obtain a maximum right steering angle, controls the steering motor to steer the steered wheels leftward to obtain a maximum left steering angle, and sets a midpoint between the maximum right steering angle and the maximum left steering angle as a neutral position of the steered wheels.

[0020] According to the above configuration, the neutral positions of the steering wheel and steered wheels are corrected, and the relative deviation between the current steering angle position and the current turning angle position due to some physical force acting on the steering wheel or steered wheels can be absorbed.

[0021] As a desirable aspect of the vehicle steering device, it is preferable that the control unit acquires the right maximum steering angle or the left maximum steering angle when it detects any one of the following: the steering torque of the steering wheel has become equal to or greater than a predetermined torque threshold; the current value of the reaction force motor has become equal to or greater than a predetermined current threshold; and the angular velocity of the reaction force motor has become equal to or less than a predetermined angular velocity threshold.

[0022] As a result, if any one of the steering torque, the current value of the reaction force motor, and the angular velocity of the reaction force motor is normal, the steering wheel position correction process can be executed.

[0023] As a desirable aspect of the vehicle steering device, it is preferable that the right maximum steering angle or the left maximum steering angle is acquired when it is detected that either the current value of the steering motor has become equal to or greater than a predetermined current threshold, or the angular velocity of the steering motor has become equal to or less than a predetermined angular velocity threshold.

[0024] As a result, if either the current value of the steering motor or the angular velocity of the steering motor is normal, the steering wheel position correction process can be executed.

[0025] As a desirable aspect of the vehicle steering device, after acquiring the right maximum steering angle and the left maximum steering angle, it is preferable that the control unit controls the reaction motor until the current position of the steering wheel becomes equal to or greater than a predetermined target steering angle.

[0026] As a desirable aspect of the vehicle steering device, after acquiring the right maximum steering angle and the left maximum steering angle, it is preferable that the control unit controls the reaction motor until the current position of the steering wheel falls within a predetermined angle range including a predetermined target steering angle.

[0027] As a desirable aspect of the vehicle steering device, after acquiring the right maximum steering angle and the left maximum steering angle, it is preferable that the control unit controls the steering motor until the current position of the steered wheels becomes equal to or greater than a predetermined target steering angle.

[0028] As a desirable aspect of the vehicle steering device, after acquiring the right maximum steering angle and the left maximum steering angle, it is preferable that the control unit controls the steering motor until the current position of the steered wheels falls within a predetermined angle range including a predetermined target steering angle.

[0029] In order to achieve the above-mentioned object, one embodiment of the present invention provides a method for adjusting a vehicle steering device, which includes a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, and includes a first step of controlling the reaction motor to steer the steering wheel to the right to obtain a maximum right-side steering angle, a second step of controlling the reaction motor to steer the steering wheel to the left to obtain a maximum left-side steering angle, and a third step of setting the midpoint between the maximum right-side steering angle and the maximum left-side steering angle as the neutral position of the steering wheel.

[0030] This corrects the neutral position of the steering wheel, and absorbs any relative deviation between the current steering angle position and the current turning angle position due to some physical force acting on the steering wheel.

[0031] As a desirable aspect of the method for adjusting a vehicle steering system, it is preferable that in the first step, the right maximum steering angle is acquired when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, and that in the second step, the left maximum steering angle is acquired when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold.

[0032] As a result, if any one of the steering torque, the current value of the reaction force motor, and the angular velocity of the reaction force motor is normal, the steering wheel position correction process can be executed.

[0033] As a preferred aspect of the method for adjusting a vehicle steering system, in the first step, the reaction force motor is driven at a first angular velocity, and after detecting any one of the following: that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold value, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold value, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold value, the reaction force motor is driven at a second angular velocity slower than the first angular velocity, and when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold value, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold value, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold value, the left maximum It is preferable that, after acquiring a steering angle, in the second step, the reaction force motor is driven at a first angular velocity and it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, and then the reaction force motor is driven at a second angular velocity slower than the first angular velocity and the left maximum steering angle is acquired when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold.

[0034] As a desirable aspect of the method for adjusting a steering device for a vehicle, it is preferable that the method further comprises a fourth step of controlling the reaction force motor after obtaining the right maximum steering angle and the left maximum steering angle, until the current position of the steering wheel becomes equal to or greater than a predetermined target steering angle.

[0035] As a desirable aspect of the method for adjusting a vehicle steering device, it is preferable that the method further comprises a fourth step of controlling the reaction motor after obtaining the right maximum steering angle and the left maximum steering angle until the current position of the steering wheel falls within a predetermined angle range including a predetermined target steering angle.

[0036] This suppresses the rebound that occurs at the maximum steering angle on the physical right side of the steering wheel or the maximum steering angle on the physical left side of the steering wheel, thereby improving the accuracy of obtaining the maximum steering angle on the right side of the steering wheel or the maximum steering angle on the left side of the steering wheel while shortening the time required for steering wheel position correction processing.

[0037] In order to achieve the above-mentioned object, one embodiment of the present invention provides a method for adjusting a vehicle steering device including a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, and includes a first step of controlling the steering motor to steer the steered wheels to the right to obtain a maximum right-side steering angle, a second step of controlling the steering motor to steer the steered wheels to the left to obtain a maximum left-side steering angle, and a third step of setting the midpoint between the maximum right-side steering angle and the maximum left-side steering angle as a neutral position of the steered wheels.

[0038] This corrects the neutral position of the steered wheels, and absorbs any relative deviation between the current steering angle position and the current turning angle position due to some physical force acting on the steering wheel.

[0039] As a desirable aspect of the method for adjusting a vehicle steering system, it is preferable that in the first step, the right maximum steering angle is obtained when it is detected that either a current value of the steering motor has become equal to or greater than a predetermined current threshold or that the angular velocity of the steering motor has become equal to or less than a predetermined angular velocity threshold, and that in the second step, the left maximum steering angle is obtained when it is detected that either a current value of the steering motor has become equal to or greater than a predetermined current threshold or that the angular velocity of the steering motor has become equal to or less than a predetermined angular velocity threshold.

[0040] As a result, if either the current value of the steering motor or the angular velocity of the steering motor is normal, the steering wheel position correction process can be executed.

[0041] As a desirable aspect of the method for adjusting a vehicle steering device, it is preferable that the method further comprises a fourth step of controlling the steering motor until the current position of the steered wheels becomes equal to or greater than a predetermined target steering angle after obtaining the right maximum steering angle and the left maximum steering angle.

[0042] As a desirable aspect of the method for adjusting a vehicle steering device, it is preferable that the method further comprises a fourth step of controlling the steering motor after obtaining the right maximum steering angle and the left maximum steering angle until the current position of the steered wheels falls within a predetermined angle range including a predetermined target steering angle.

[0043] In order to achieve the above object, a method for adjusting a vehicle steering system according to one aspect of the present invention is a method for adjusting a vehicle steering system including a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, the method including a first step of controlling the reaction motor to steer the steering wheel rightward to obtain a maximum rightward steering angle, and a second step of controlling the reaction motor to steer the steering wheel leftward to obtain a maximum rightward steering angle. a third step of setting the midpoint between the right maximum steering angle and the left maximum steering angle as the neutral position of the steering wheel; a fourth step of controlling the steering motor to steer the steered wheels to the right to obtain the right maximum steering angle; a fifth step of controlling the steering motor to steer the steered wheels to the left to obtain the left maximum steering angle; and a sixth step of setting the midpoint between the right maximum steering angle and the left maximum steering angle as the neutral position of the steered wheels.

[0044] This corrects the neutral positions of the steering wheel and steered wheels, and absorbs any relative deviation between the current steering angle position and the current turning angle position due to some physical force acting on the steering wheel or steered wheels.

[0045] As a desirable aspect of the method for adjusting a vehicle steering system, it is preferable that in the first step, the right maximum steering angle is acquired when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, and that in the second step, the left maximum steering angle is acquired when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold.

[0046] As a result, if any one of the steering torque, the current value of the reaction force motor, and the angular velocity of the reaction force motor is normal, the steering wheel position correction process can be executed.

[0047] As a preferred aspect of the method for adjusting a vehicle steering system, in the first step, the reaction force motor is driven at a first angular velocity, and after detecting any one of the following: that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold value, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold value, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold value, the reaction force motor is driven at a second angular velocity slower than the first angular velocity, and when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold value, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold value, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold value, the left maximum It is preferable that, after acquiring a steering angle, in the second step, the reaction force motor is driven at a first angular velocity and it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, and then the reaction force motor is driven at a second angular velocity slower than the first angular velocity and the left maximum steering angle is acquired when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold.

[0048] This suppresses the rebound that occurs at the maximum steering angle on the physical right side of the steering wheel or the maximum steering angle on the physical left side of the steering wheel, thereby improving the accuracy of obtaining the maximum steering angle on the right side of the steering wheel or the maximum steering angle on the left side of the steering wheel while shortening the time required for steering wheel position correction processing.

[0049] As a desirable aspect of the method for adjusting a vehicle steering system, it is preferable that in the fourth step, the right maximum steering angle is acquired when it is detected that either a current value of the steering motor has become equal to or greater than a predetermined current threshold or that an angular velocity of the steering motor has become equal to or less than a predetermined angular velocity threshold, and that in the fifth step, the left maximum steering angle is acquired when it is detected that either a current value of the steering motor has become equal to or greater than a predetermined current threshold or that an angular velocity of the steering motor has become equal to or less than a predetermined angular velocity threshold.

[0050] As a result, if either the current value of the steering motor or the angular velocity of the steering motor is normal, the steering wheel position correction process can be executed.

[0051] As a desirable aspect of the method for adjusting a vehicle steering system, it is preferable that the method further comprises a seventh step of controlling the reaction force motor after obtaining the right maximum steering angle and the left maximum steering angle until the current position of the steering wheel becomes equal to or greater than a predetermined target steering angle, and an eighth step of controlling the steering motor after obtaining the right maximum steering angle and the left maximum steering angle until the current position of the steered wheels becomes equal to or greater than a predetermined target steering angle.

[0052] As a desirable aspect of the method for adjusting a vehicle steering system, it is preferable that the method further comprises a seventh step of controlling the reaction motor after obtaining the right maximum steering angle and the left maximum steering angle, until the current position of the steering wheel falls within a predetermined angle range including a predetermined target steering angle, and an eighth step of controlling the steering motor after obtaining the right maximum steering angle and the left maximum steering angle, until the current position of the steered wheels falls within a predetermined angle range including the predetermined target steering angle. [Effects of the Invention]

[0053] According to the present invention, it is possible to provide a vehicle steering system and a method for adjusting a vehicle steering system that can absorb the relative difference between the steering angle and the turning angle. [Brief explanation of the drawings]

[0054] [Figure 1] FIG. 1 is a diagram showing the overall configuration of a steer-by-wire type vehicle steering device. [Figure 2] FIG. 2 is a schematic diagram showing the hardware configuration of a control unit that controls the SBW system. [Figure 3] FIG. 3 is a diagram showing the relationship between the steering angle and the turning angle in the SBW system. [Figure 4] FIG. 4 is a flowchart illustrating an example of the handle position correction process according to the first embodiment. [Figure 5] FIG. 5 is a flowchart illustrating an example of the right maximum steering angle acquisition process according to the first embodiment. [Figure 6] FIG. 6 is a flowchart illustrating an example of the left maximum steering angle acquisition process according to the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating the operation of the steering wheel position correction process according to the first embodiment. [Figure 8] FIG. 8 is a flowchart illustrating an example of a right maximum steering angle acquisition process according to the first modification of the first embodiment. [Figure 9] FIG. 9 is a flowchart illustrating an example of a left maximum steering angle acquisition process according to the first modification of the first embodiment. [Figure 10] FIG. 10 is a diagram illustrating the operation of the steering wheel position correction process according to the first modification of the first embodiment. [Figure 11] FIG. 11 is a flowchart illustrating an example of a right maximum steering angle acquisition process according to the second modification of the first embodiment. [Figure 12] FIG. 12 is a flowchart illustrating an example of a left maximum steering angle acquisition process according to the second modification of the first embodiment. [Figure 13] FIG. 13 is a diagram illustrating the operation of the steering wheel position correction process according to the second modification of the first embodiment. [Figure 14] FIG. 14 is a flowchart illustrating an example of a right maximum steering angle acquisition process according to the third modification of the first embodiment. [Figure 15]FIG. 15 is a flowchart illustrating an example of a left maximum steering angle acquisition process according to the third modification of the first embodiment. [Figure 16A] FIG. 16A is a diagram showing a specific example in which the drive speed of the reaction force motor is relatively high in the steering wheel position correction process. [Figure 16B] FIG. 16B is a diagram showing a specific example in which the drive speed of the reaction force motor is relatively high in the steering wheel position correction process. [Figure 17A] FIG. 17A is a diagram showing a specific example in which the drive speed of the reaction force motor is relatively slow in the steering wheel position correction process. [Figure 17B] FIG. 17B is a diagram showing a specific example in which the drive speed of the reaction force motor is relatively slow in the steering wheel position correction process. [Figure 18] FIG. 18 is a flowchart illustrating an example of a right maximum steering angle acquisition process according to the fourth modification of the first embodiment. [Figure 19] FIG. 19 is a flowchart illustrating an example of a left maximum steering angle acquisition process according to the fourth modification of the first embodiment. [Figure 20] FIG. 20 is a flowchart illustrating an example of a right maximum steering angle acquisition process according to the fifth modification of the first embodiment. [Figure 21] FIG. 21 is a flowchart illustrating an example of a left maximum steering angle acquisition process according to the fifth modification of the first embodiment. [Figure 22] FIG. 22 is a flowchart illustrating an example of a right maximum steering angle acquisition process according to the sixth modification of the first embodiment. [Figure 23] FIG. 23 is a flowchart illustrating an example of a left maximum steering angle acquisition process according to the sixth modification of the first embodiment. [Figure 24] FIG. 24 is a flowchart illustrating an example of a right maximum steering angle acquisition process according to the seventh modification of the first embodiment. [Figure 25] FIG. 25 is a flowchart illustrating an example of a left maximum steering angle acquisition process according to the seventh modification of the first embodiment. [Figure 26] FIG. 26 is a flowchart illustrating an example of a steered wheel position correction process according to the second embodiment. [Figure 27] FIG. 27 is a flowchart showing an example of the right maximum steering angle acquisition process according to the second embodiment. [Figure 28] FIG. 28 is a flowchart showing an example of the left maximum steering angle acquisition process according to the second embodiment. [Figure 29] FIG. 29 is a diagram illustrating the operation of the steered wheel position correction process according to the second embodiment. [Figure 30] FIG. 30 is a flowchart showing an example of a right maximum steering angle acquisition process according to the first modification of the second embodiment. [Figure 31] FIG. 31 is a flowchart showing an example of the left maximum steering angle acquisition process according to the first modification of the second embodiment. [Figure 32] FIG. 32 is a diagram illustrating the operation of the steered wheel position correction process according to the first modification of the second embodiment. [Figure 33] FIG. 33 is a flowchart showing an example of a right maximum steering angle acquisition process according to the second modification of the second embodiment. [Figure 34] FIG. 34 is a flowchart showing an example of a left maximum steering angle acquisition process according to the second modification of the second embodiment. [Figure 35] FIG. 35 is a flowchart illustrating an example of the position correction process according to the third embodiment. [Figure 36] FIG. 36 is a flowchart illustrating an example of the position correction process according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0055] Hereinafter, modes for carrying out the invention (hereinafter referred to as embodiments) will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments. Furthermore, the components in the following embodiments include those that can be easily imagined by a person skilled in the art, those that are substantially the same, and those that are within the so-called equivalent range. Furthermore, the components disclosed in the following embodiments can be combined as appropriate.

[0056] Fig. 1 is a diagram showing the overall configuration of a steer-by-wire type vehicle steering device. The steer-by-wire (SBW) type vehicle steering device (hereinafter also referred to as "SBW system") shown in Fig. 1 is a system that transmits the operation of a steering wheel 1 to a steering mechanism consisting of steered wheels 8L, 8R, etc., by means of an electric signal. As shown in Fig. 1, the SBW system includes a reaction force device 60 and a drive device 70, and a control unit (hereinafter also referred to as "ECU") 50 controls both devices.

[0057] The reaction force device 60 includes a torque sensor 10 that detects the steering torque Ts of the steering wheel 1, a steering angle sensor 14 that detects the steering angle θh, a speed reduction mechanism 3, an angle sensor 74, a reaction force motor 61, etc. Each of these components is provided on the column shaft 2 of the steering wheel 1.

[0058] The reaction force device 60 detects the steering angle θh using the steering angle sensor 14, and simultaneously transmits the vehicle's motion state transmitted from the steered wheels 8L, 8R to the driver as a reaction torque. The reaction torque is generated by a reaction force motor 61. The torque sensor 10 detects the steering torque Ts. In addition, an angle sensor 74 detects the motor angle θhm of the reaction force motor 61.

[0059] Drive device 70 includes steering motor 71, gear 72, angle sensor 73, etc. The driving force generated by steering motor 71 passes through gear 72, pinion rack mechanism 5, tie rods 6a, 6b, and is further coupled to steered wheels 8L, 8R via hub units 7a, 7b.

[0060] Drive device 70 drives steering motor 71 in accordance with the steering of steering wheel 1 by the driver, and the resulting driving force is applied to pinion rack mechanism 5 via gear 72, and then via tie rods 6a and 6b to steer steered wheels 8L, 8R. An angle sensor 73 is disposed near pinion rack mechanism 5 and detects the steering angle θt of steered wheels 8L, 8R. In order to cooperatively control reaction force device 60 and drive device 70, ECU 50 generates a voltage control command value Vref1 for driving and controlling reaction force motor 61 and a voltage control command value Vref2 for driving and controlling steering motor 71 based on information such as steering angle θh and steering angle θt output from both devices, as well as vehicle speed Vs from vehicle speed sensor 12.

[0061] Angle sensor 73 may be configured to detect motor angle θtm of steering motor 71 instead of steering angle θt. In this case, motor angle θtm, which is the detected value of angle sensor 73, may be converted into steering angle θt and used for subsequent control.

[0062] ECU 50 is supplied with power from battery 13 and also receives an ignition key signal via ignition key 11. ECU 50 calculates a current command value based on steering torque Ts detected by torque sensor 10, vehicle speed Vs detected by vehicle speed sensor 12, etc., and controls the currents supplied to reaction force motor 61 and steering motor 71.

[0063] An in-vehicle network such as a Controller Area Network (CAN) 40 that transmits and receives various types of vehicle information is connected to the ECU 50. In addition, a non-CAN 41 that transmits and receives communications other than the CAN 40, analog / digital signals, radio waves, etc. can also be connected to the ECU 50.

[0064] The ECU 50 is mainly composed of a CPU (including an MCU, an MPU, etc.) Figure 2 is a schematic diagram showing the hardware configuration of an ECU that controls the SBW system.

[0065] The control computer 1100 constituting the ECU 50 includes a CPU (Central Processing Unit) 1001, a ROM (Read Only Memory) 1002, a RAM (Random Access Memory) 1003, an EEPROM (Electrically Erasable Programmable ROM) 1004, an interface (I / F) 1005, an A / D (Analog / Digital) converter 1006, a PWM (Pulse Width Modulation) controller 1007, etc., which are connected to a bus.

[0066] The CPU 1001 is a processing device that executes a computer program for controlling the SBW system (hereinafter referred to as a control program) to control the SBW system.

[0067] The ROM 1002 stores a control program for controlling the SBW system. The RAM 1003 is used as a work memory for running the control program. The EEPROM 1004 stores control data and the like input and output by the control program. The control data is used by the control computer program loaded in the RAM 1003 after power is applied to the ECU 30, and is overwritten in the EEPROM 1004 at a predetermined timing.

[0068] The ROM 1002, RAM 1003, EEPROM 1004, etc. are storage devices that store information and are storage devices (primary storage devices) that the CPU 1001 can directly access.

[0069] An A / D converter 1006 receives signals such as the steering torque Ts and steering angle θh and converts them into digital signals.

[0070] The interface 1005 is connected to the CAN 40. The interface 1005 is for receiving a signal of the vehicle speed V (vehicle speed pulse) from the vehicle speed sensor 12.

[0071] The PWM controller 1007 outputs PWM control signals for each of the UVW phases based on current command values ​​for the reaction force motor 61 and the steering motor 71 .

[0072] In the SBW system described above, the reaction force device 60 and the drive device 70 are mechanically separated. Therefore, the ECU 50 controls the steering angle θh and the turning angle θt so that they have a predetermined relationship. Specifically, the ECU 50 controls the steering angle θh_cen so that the center position (hereinafter also referred to as the "neutral position") of the steering wheel 1 coincides with the neutral position θt_cen of the steered wheels 8L, 8R. Figure 3 is a diagram showing the relationship between the steering angle and the turning angle in the SBW system.

[0073] As shown in FIG. 3, when the neutral position θh_cen of the steering wheel 1 and the neutral position θt_cen of the steered wheels 8L and 8R coincide, the position of the right steering end of the steering wheel 1 coincides with the position of the right steering end of the steered wheels 8L and 8R, and the position of the left steering end of the steering wheel 1 coincides with the position of the left steering end of the steered wheels 8L and 8R. The position of the right steering end of the steering wheel 1 is defined by the right maximum steering angle θh_R_end. The position of the left steering end of the steering wheel 1 is defined by the left maximum steering angle θh_L_end. The position of the right steering end of the steered wheels 8L and 8R is defined by the right maximum steering angle θt_R_end. The position of the left steering end of the steered wheels 8L and 8R is defined by the left maximum steering angle θt_L_end.

[0074] (Embodiment 1) The relationship between the steering angle θh and the motor angle θhm of the reaction force motor 61 is shown in the following equation (1): In equation (1), k1 is a coefficient given by the gear ratio of the reduction mechanism 3.

[0075] θh=k1×θhm (1)

[0076] 1 cannot detect the steering angle θh, the ECU 50 obtains the current position of the steering wheel 1 by the above equation (1) using the motor angle θhm of the reaction force motor 61 detected by the angle sensor 74. Specifically, while the vehicle is traveling, the ECU 50 calculates the current position θh_abs by accumulating the time change Δθh of the steering angle θh with respect to the previous value of the steering angle θh, and stores the calculated position in the EEPROM 1004 sequentially.

[0077] In this case, for example, if some kind of physical external force acts on the steering wheel 1 while the vehicle is stopped, a deviation may occur between the current position θh_abs of the steering wheel 1 stored in the EEPROM 1004 while the vehicle is moving, and an error may occur when processing to obtain the current position of the steering wheel 1 is started. Furthermore, errors may accumulate while the vehicle is moving, causing the neutral position θh_cen of the steering wheel 1 to shift.

[0078] Fig. 4 is a flowchart showing an example of a steering wheel position correction process according to the first embodiment. Fig. 5 is a flowchart showing an example of a right maximum steering angle acquisition process according to the first embodiment. Fig. 6 is a flowchart showing an example of a left maximum steering angle acquisition process according to the first embodiment. Fig. 7 is a diagram for explaining the operation of the steering wheel position correction process according to the first embodiment. Here, an example will be described in which the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end are acquired using the steering torque Ts detected by the torque sensor 10.

[0079] 4 can be performed, for example, at the time of starting up the ECU 50. The timing of performing the steering wheel position correction process is not limited to the time of starting up the ECU 50, and may be, for example, before the ECU 50 is stopped.

[0080] Since it is cumbersome to perform the position correction process each time the ECU 50 is started or stopped, it is desirable that the steering wheel position correction process be performed by operating a button or touch panel (not shown) when the driver recognizes a discrepancy between the steering wheel 1 and the steering angle θt.

[0081] First, the ECU 50 initializes the counter value N of the number of times the steering wheel position correction process is performed (N = 0) (step S11). The maximum value Nth of the number of times the steering wheel position correction process is performed is preset to, for example, 3.

[0082] Subsequently, the ECU 50 adds 1 to the counter value N of the number of times the steering wheel position correction process is performed (N = N + 1) (step S12), and executes the right maximum steering angle acquisition process shown in FIG. 5 (step S13).

[0083] As shown in FIG. 7, in step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the right (step S131, (1) in FIG. 7), and determines whether or not the absolute value |Ts| of the steering torque Ts is greater than or equal to a preset torque threshold value Tth (|Ts| ≥ Tth) (step S132).

[0084] If the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts| < Tth) (step S132; No), the process returns to step S131.

[0085] When the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold value Tth (|Ts| ≥ Tth) (step S132; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the right maximum steering angle θh_R_end in the EEPROM 1004 (step S133), and returns to the steering wheel position correction process shown in FIG. 4.

[0086] Subsequently, the ECU 50 executes the left maximum steering angle acquisition process shown in FIG. 6 (step S14).

[0087] As shown in FIG. 7, in step S14 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the left (step S141, (2) in FIG. 7), and determines whether or not the absolute value |Ts| of the steering torque Ts is greater than or equal to the torque threshold value Tth (|Ts| ≥ Tth) (step S142).

[0088] When the maximum steering angle θh_R_end is reached, it contacts a rotation stopper that mechanically restricts the rotation of the column shaft 2 of the steering wheel 1, and the rotation of the column shaft 2 is restricted. By continuously supplying current to the reaction motor 2 while the rotation of the column shaft 2 is restricted, the steering torque Ts increases.

[0089] When the absolute value |Ts| of the steering torque Ts is less than the torque threshold Tth (|Ts| < Tth) (step S142; No), the process returns to the process of step S141.

[0090] When the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold Tth (|Ts| ≥ Tth) (step S142; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the left maximum steering angle θh_L_end in the EEPROM 1004 (step S143), and returns to the steering wheel position correction process shown in FIG. 4.

[0091] The ECU 50 determines whether the absolute value (|θh_R_end - θh_L_end|) of the difference between the right maximum steering angle θh_R_end obtained in step S13 and the left maximum steering angle θh_L_end obtained in step S14 is greater than or equal to the threshold θhth (|θh_R_end - θh_L_end| ≥ θhth) (step S15). The threshold θhth is preset based on the physical movable range of the steering wheel 1. The threshold θhth is defined by, for example, the following equation (2). In the following equation (2), θh_R_end(real) represents the physical right maximum steering angle of the steering wheel 1, and θh_L_end(real) represents the physical left maximum steering angle of the steering wheel 1.

[0092] θhth < |θh_R_end(real) - θh_L_end(real)| ··· (2)

[0093] Here, when the absolute value of the difference between the right maximum steering angle θh_R_end obtained in step S13 and the left maximum steering angle θh_L_end obtained in step S14 is less than the threshold value θhth (|θh_R_end - θh_L_end| < θhth) (step S15; No), it is considered that some physical external force has acted on the steering wheel 1 while the reaction motor 61 is being driven (step S131 or step S141), and the absolute value |Ts| of the steering torque Ts has become equal to or greater than the torque threshold value Tth (step S132; Yes or step S142; Yes). In this case, the process proceeds to step S16, and it is determined whether the counter value N of the number of times of performing the steering wheel position correction process is equal to or greater than the maximum value Nth of the number of times of performing the steering wheel position correction process (N ≧ Nth) (step S16). If N < Nth (step S16; No), the process returns to the process of step S12, and the above-described process is retried. If N ≧ Nth (step S16; Yes), the steering wheel position correction process is interrupted.

[0094] When the absolute value (|θh_R_end - θh_L_end|) of the difference between the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end is equal to or greater than the threshold value θhth (|θh_R_end - θh_L_end| ≧ θhth) (step S15; Yes), the right maximum steering angle θh_R_end obtained in step S13 and the left maximum steering angle θh_L_end obtained in step S14 can be respectively determined to be the physical right maximum steering angle of the steering wheel 1 and the physical left maximum steering angle of the steering wheel 1 that have been obtained. That is, the midpoint between the right maximum steering angle θh_R_end obtained in step S13 and the left maximum steering angle θh_L_end obtained in step S14 can be regarded as the neutral position θh_cen of the steering wheel 1. The ECU 50 calculates the neutral position θh_cen of the steering wheel 1 using the following formula (3) (step S17).

[0095] θh_cen = θh_L_end + (θh_R_end - θh_L_end) / 2 ··· (3)

[0096] Here, the neutral position θh_cen of the steering wheel 1 may be offset to "0." In this case, the right maximum steering angle θh_R_end is a value obtained by offsetting the value acquired in step S13 by the neutral position θh_cen calculated by the above equation (3), and the left maximum steering angle θh_L_end is a value obtained by offsetting the value acquired in step S14 by the neutral position θh_cen calculated by the above equation (3).

[0097] Next, the ECU 50 calculates the target steering angle θh_tp (step S18). The target steering angle θh_tp may be, for example, the neutral position θh_cen of the steering wheel 1 or a predetermined position corresponding to the current position θt_abs of the steering angle θt.

[0098] As shown in Fig. 7, the ECU 50 drives the reaction force motor 61 to steer the steering wheel 1 to the right (step S19, (3) in Fig. 7) until the current position θh_abs of the steering wheel 1 becomes equal to or greater than the target steering angle θh_tp (step S20; Yes). When the current position θh_abs of the steering wheel 1 becomes equal to or greater than the target steering angle θh_tp, the driving of the reaction force motor 61 is stopped, so that the current position θh_abs and the target steering angle θh_tp can be made to match. In other words, the steering wheel 1 can be moved to the position of the target steering angle θh_tp.

[0099] Note that instead of driving the reaction force motor 61 so as to steer the steering wheel 1 to the right until the current position θh_abs of the steering wheel 1 becomes equal to or greater than the target steering angle θh_tp, the reaction force motor 61 may be driven so as to steer the steering wheel 1 to the right until the current position θh_abs of the steering wheel 1 becomes a value within a predetermined angle range including the target steering angle θh_tp. For example, if the target steering angle θh_tp calculated from the current position θt_abs of the steering angle θt is 60°, the reaction force motor 61 may be steered so as to steer the steering wheel 1 to the right until the current position θh_abs of the steering wheel 1 falls within a range of 60±1°.

[0100] In short, the steering wheel 1 may be driven until it reaches a position substantially coinciding with the target steering angle θh_tp.

[0101] When the current position θh_abs of the steering wheel 1 becomes equal to or greater than the target steering angle θh_tp (step S20; Yes), the ECU 50 ends the steering wheel position correction process.

[0102] (Modification Example 1) FIG. 8 is a flowchart showing an example of the right maximum steering angle acquisition process according to Modification Example 1 of Embodiment 1. FIG. 9 is a flowchart showing an example of the left maximum steering angle acquisition process according to Modification Example 1 of Embodiment 1. FIG. 10 is a diagram for explaining the operation in the steering wheel position correction process according to Modification Example 1 of Embodiment 1.

[0103] The torque sensor 10 may be configured as a component in the same package as the steering angle sensor 14. For example, when the steering angle θh cannot be detected by the steering angle sensor 14 shown in FIG. 1, there is a possibility that the steering torque Ts cannot be detected by the torque sensor 10 at the same time. Here, an example of obtaining the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end using the current value Imr of the reaction force motor 61 (see FIG. 1) will be described.

[0104] After the process of step S12 shown in FIG. 4, the ECU 50 executes the right maximum steering angle acquisition process shown in FIG. 8 (step S13).

[0105] As shown in FIG. 10, the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 in the right direction in step S13 shown in FIG. 4 (step S131, (1) in FIG. 10), and determines whether or not the absolute value |Imr| of the current value Imr of the reaction force motor 61 is equal to or greater than a preset current threshold Imrth (|Imr|≧Imrth) (step S132a).

[0106] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold Imrth (|Imr|<Imrth) (step S132a; No), the process returns to step S131.

[0107] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes equal to or greater than the current threshold value Imrth (|Imr| ≥ Imrth) (step S132a; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the right maximum steering angle θh_R_end in the EEPROM 1004 (step S133), and returns to the steering wheel position correction process shown in FIG. 4.

[0108] Subsequently, the ECU 50 executes the left maximum steering angle acquisition process shown in FIG. 9 (step S14).

[0109] As shown in FIG. 10, in step S14 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 in the left direction (step S141, (2) in FIG. 10), and determines whether or not the absolute value |Imr| of the current value Imr of the reaction force motor 61 is equal to or greater than the current threshold value Imrth (|Imr| ≥ Imrth) (step S142a).

[0110] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold value Imrth (|Imr| < Imrth) (step S142a; No), the process returns to step S141.

[0111] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes equal to or greater than the current threshold value Imrth (|Imr| ≥ Imrth) (step S142a; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the left maximum steering angle θh_L_end in the EEPROM 1004 (step S143), and returns to the steering wheel position correction process shown in FIG. 4.

[0112] (Modification 2) Fig. 11 is a flowchart showing an example of a right maximum steering angle acquisition process according to Modification 2 of Embodiment 1. Fig. 12 is a flowchart showing an example of a left maximum steering angle acquisition process according to Modification 2 of Embodiment 1. Fig. 13 is a diagram illustrating the operation of the steering wheel position correction process according to Modification 2 of Embodiment 1. Here, an example will be described in which the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end are acquired using the angular velocity ωr of the reaction force motor 61. The angular velocity ωr of the reaction force motor 61 is obtained by time differentiating the motor angle θhm of the reaction force motor 61 detected by the angle sensor 74.

[0113] After the process of step S12 shown in FIG. 4, the ECU 50 executes a right maximum steering angle acquisition process shown in FIG. 11 (step S13).

[0114] As shown in FIG. 13, in step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the right (step S131, (1) in FIG. 13), and determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is equal to or less than a preset angular velocity threshold value ωrth (|ωr|≦ωrth) (step S132b).

[0115] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold ωrth (|ωr|>ωrth) (step S132b; No), the process returns to step S131.

[0116] When the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes equal to or less than the angular velocity threshold ωrth (step S132b; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time in the EEPROM 1004 as the maximum right steering angle θh_R_end (step S133), and returns to the steering wheel position correction processing shown in Figure 4.

[0117] Next, the ECU 50 executes a left maximum steering angle acquisition process shown in FIG. 12 (step S14).

[0118] As shown in FIG. 13, in step S14 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the right (step S141, (2) in FIG. 13), and determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is equal to or less than the angular velocity threshold value ωrth (|ωr|≦ωrth) (step S142b).

[0119] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold value ωrth (|ωr|>ωrth) (step S142b; No), the process returns to step S141.

[0120] When the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes equal to or less than the angular velocity threshold ωrth (step S142b; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time in the EEPROM 1004 as the maximum left steering angle θh_L_end (step S143), and returns to the steering wheel position correction processing shown in Figure 4.

[0121] (Variation 3) Fig. 14 is a flowchart showing an example of a right maximum steering angle acquisition process according to Modification 3 of Embodiment 1. Fig. 15 is a flowchart showing an example of a left maximum steering angle acquisition process according to Modification 3 of Embodiment 1. Here, an example will be described in which the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end are acquired using the steering torque Ts detected by the torque sensor 10, the current value Imr of the reaction force motor 61, and the angular velocity ωr of the reaction force motor 61.

[0122] After the process of step S12 shown in FIG. 4, the ECU 50 executes a right maximum steering angle acquisition process shown in FIG. 14 (step S13).

[0123] In step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the right (step S131), and determines whether the absolute value |Ts| of the steering torque Ts is equal to or greater than the torque threshold value Tth (|Ts|≧Tth) (step S132).

[0124] If the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts| < Tth) (step S132; No), then subsequently, the ECU 50 determines whether the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold value Imrth (|Imr| ≥ Imrth) (step S132a).

[0125] If the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold value Imrth (|Imr| < Imrth) (step S132a; No), then subsequently, the ECU 50 determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is less than or equal to the angular velocity threshold value ωrth (|ωr| ≤ ωrth) (step S132b).

[0126] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold value ωrth (|ωr| > ωrth) (step S132b; No), the process returns to step S131.

[0127] When the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold value Tth (|Ts| ≥ Tth) (step S132; Yes), the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold value Imrth (|Imr| ≥ Imrth) (step S132a; Yes), or the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes less than or equal to the angular velocity threshold value ωrth (|ωr| ≤ ωrth) (step S132b; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the right maximum steering angle θh_R_end in the EEPROM 1004 (step S133), and returns to the steering wheel position correction process shown in FIG. 4.

[0128] Subsequently, the ECU 50 executes the left maximum steering angle acquisition process shown in FIG. 15 (step S14).

[0129] In step S14 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 in the left direction (step S141), and determines whether or not the absolute value |Ts| of the steering torque Ts is greater than or equal to the torque threshold value Tth (|Ts|≥Tth) (step S142).

[0130] If the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts|<Tth) (step S142; No), then subsequently, the ECU 50 determines whether or not the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold value Imrth (|Imr|≥Imrth) (step S142a).

[0131] If the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold value Imrth (|Imr|<Imrth) (step S142a; No), then subsequently, the ECU 50 determines whether or not the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is less than or equal to the angular velocity threshold value ωrth (|ωr|≤ωrth) (step S142b).

[0132] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold value ωrth (|ωr|>ωrth) (step S142b; No), the process returns to step S141.

[0133] When the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold value Tth (|Ts|≥Tth) (step S142; Yes), when the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold value Imrth (|Imr|≥Imrth) (step S142a; Yes), or when the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes less than or equal to the angular velocity threshold value ωrth (step S142b; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the left maximum steering angle θh_L_end in the EEPROM 1004 (step S143), and returns to the steering wheel position correction process shown in FIG. 4.

[0134] As a result, if any one of the steering torque Ts detected by the torque sensor 10, the current value Imr of the reaction force motor 61, and the angular velocity ωr of the reaction force motor 61 is normal, the steering wheel position correction process can be executed.

[0135] (Variation 4) Figures 16A and 16B are diagrams showing a specific example when the drive speed of the reaction force motor is relatively fast in the steering wheel position correction process. Figures 17A and 17B are diagrams showing a specific example when the drive speed of the reaction force motor is relatively slow in the steering wheel position correction process. Figures 16A and 17A show the time change in the angular velocity ωr of the reaction force motor 61, and Figures 16B and 17B show the time change in the steering angle θh obtained from the motor angle θhm of the reaction force motor 61 using the above equation (1).

[0136] As shown in Figures 16A and 16B, in the above-mentioned steering wheel position correction process, if the driving speed of the reaction force motor 61 is relatively fast, at time t_end, a bounce will occur in the physical right maximum steering angle θh_R_end(real) of the steering wheel 1 or the physical left maximum steering angle θh_L_end(real) of the steering wheel 1, which may reduce the accuracy of the right maximum steering angle θh_R_end of the steering wheel 1 or the left maximum steering angle θh_L_end of the steering wheel 1 obtained in the steering wheel position correction process. Specifically, for example, when the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end are obtained using the steering torque Ts detected by the torque sensor 10 as described in embodiment 1, if there is a time lag Δt from the point at time t_end when the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold Tth (|Ts|≧Tth) (step S132; Yes) to the actual acquisition of the current position θh_abs of the steering angle θh, it is possible that a value far removed from the physical right maximum steering angle θh_R_end(real) of the steering wheel 1 or the physical left maximum steering angle θh_L_end(real) of the steering wheel 1 will be acquired as the right maximum steering angle θh_R_end of the steering wheel 1 or the left maximum steering angle θh_L_end of the steering wheel 1.

[0137] On the other hand, as shown in FIGS. 17A and 17B, when the driving speed of the reaction force motor 61 is relatively slow, at time t_end, the bounce occurring at the physical right maximum steering angle θh_R_end(real) of the steering wheel 1 or the physical left maximum steering angle θh_L_end(real) of the steering wheel 1 can be suppressed, and the acquisition accuracy of the right maximum steering angle θh_R_end of the steering wheel 1 or the left maximum steering angle θh_L_end of the steering wheel 1 can be improved. On the other hand, when the driving speed of the reaction force motor 61 is reduced, the time required for the steering wheel position correction process becomes longer.

[0138] FIG. 18 is a flowchart showing an example of the right maximum steering angle acquisition process according to Modification 4 of Embodiment 1. FIG. 19 is a flowchart showing an example of the left maximum steering angle acquisition process according to Modification 4 of Embodiment 1. Here, an example of acquiring the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end using the steering torque Ts detected by the torque sensor 10 will be described.

[0139] After the process of step S12 shown in FIG. 4, the ECU 50 executes the right maximum steering angle acquisition process shown in FIG. 18 (step S13).

[0140] In step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at the first angular velocity ωr1 so as to steer the steering wheel 1 in the right direction (step S131a), and determines whether the absolute value |Ts| of the steering torque Ts is greater than or equal to the torque threshold value Tth (|Ts|≧Tth) (step S132).

[0141] When the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts|<Tth) (step S132; No), the process returns to step S131a.

[0142] When the absolute value |Ts| of the steering torque Ts becomes equal to or greater than the torque threshold value Tth (|Ts| ≥ Tth) (Step S132; Yes), the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the left until a predetermined time T elapses (Step S135) (Step S134).

[0143] When the predetermined time T elapses (Step S135; Yes), in Step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at a second angular velocity ωr2 that is relatively slower than the first angular velocity ωr1 so as to steer the steering wheel 1 to the right (Step S136), and determines whether or not the absolute value |Ts| of the steering torque Ts is equal to or greater than the torque threshold value Tth (|Ts| ≥ Tth) (Step S137).

[0144] When the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts| < Tth) (Step S137; No), the process returns to the process of Step S136.

[0145] When the absolute value |Ts| of the steering torque Ts becomes equal to or greater than the torque threshold value Tth (|Ts| ≥ Tth) (Step S137; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the right maximum steering angle θh_R_end in the EEPROM 1004 (Step S133), and returns to the steering wheel position correction process shown in FIG. 4.[[ID=​​​​​​​​​​​

[0149] When the absolute value |Ts| of the steering torque Ts becomes equal to or greater than the torque threshold value Tth (|Ts| ≥ Tth) (step S142; Yes), the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 in the right direction until a predetermined time T elapses (step S145) (step S144).

[0150] When the predetermined time T elapses (step S145; Yes), the ECU 50 drives the reaction force motor 61 at a second angular velocity ωr2 that is relatively slower than the first angular velocity ωr1 so as to steer the steering wheel 1 in the left direction in step S14 shown in FIG. 4 (step S146), and determines whether the absolute value |Ts| of the steering torque Ts is equal to or greater than the torque threshold value Tth (|Ts| ≥ Tth) (step S147).

[0151] When the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts| < Tth) (step S147; No), the process returns to the process of step S146.

[0152] When the absolute value |Ts| of the steering torque Ts becomes equal to or greater than the torque threshold value Tth (|Ts| ≥ Tth) (step S147; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the left maximum steering angle θh_L_end in the EEPROM 1004 (step S143), and returns to the steering wheel position correction process shown in FIG. 4.

[0153] Thereby, it is possible to suppress the backlash that occurs at the physical right maximum steering angle θh_R_end (real) of the steering wheel 1 or the physical left maximum steering angle θh_L_end (real) of the steering wheel 1, improve the acquisition accuracy of the right maximum steering angle θh_R_end or the left maximum steering angle θh_L_end of the steering wheel 1, and shorten the time required for the steering wheel position correction process.

[0154] (Modification 5) FIG. 20 is a flowchart showing an example of the right maximum steering angle acquisition process according to Modification 5 of Embodiment 1. FIG. 21 is a flowchart showing an example of the left maximum steering angle acquisition process according to Modification 5 of Embodiment 1. Here, an example of acquiring the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end using the current value Imr (see FIG. 1) of the reaction force motor 61 will be described.

[0155] After the process of step S12 shown in FIG. 4, the ECU 50 executes the right maximum steering angle acquisition process shown in FIG. 20 (step S13).

[0156] In step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at the first angular velocity ωr1 so as to steer the steering wheel 1 in the right direction (step S131a), and determines whether the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold Imrth (|Imr|≧Imrth) (step S132a).

[0157] If the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold Imrth (|Imr|<Imrth) (step S132a; No), the process returns to step S131a.

[0158] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold Imrth (|Imr|≧Imrth) (step S132a; Yes), the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 in the left direction until a predetermined time T elapses (step S135) (step S134).

[0159] When the predetermined time T elapses (step S135; Yes), in step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at a second angular velocity ωr2 that is relatively slower than the first angular velocity ωr1 so as to steer the steering wheel 1 in the right direction (step S136), and determines whether the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold Imrth (|Imr|≧Imrth) (step S137a).

[0160] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold Imrth (|Imr| < Imrth) (step S137a; No), the process returns to the process of step S136.

[0161] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold Imrth (|Imr| ≥ Imrth) (step S137a; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the right maximum steering angle θh_R_end in the EEPROM 1004 (step S133), and returns to the steering wheel position correction process shown in FIG. 4.

[0162] Subsequently, the ECU 50 executes the left maximum steering angle acquisition process shown in FIG. 19 (step S14).

[0163] In step S14 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at the first angular velocity ωr1 so as to steer the steering wheel 1 to the left (step S141a), and determines whether the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold Imrth (|Imr| ≥ Imrth) (step S142a).

[0164] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold Imrth (|Imr| < Imrth) (step S142a; No), the process returns to the process of step S141a.

[0165] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold Imrth (|Imr| ≥ Imrth) (step S142a; Yes), the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the right until a predetermined time T elapses (step S145) (step S144).

[0166] When the specified time T has elapsed (step S145; Yes), the ECU 50 drives the reaction force motor 61 at a second angular velocity ωr2 that is relatively slower than the first angular velocity ωr1 so as to steer the steering wheel 1 in the left direction in step S14 shown in FIG. 4 (step S146), and determines whether or not the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold value Imrth (|Imr|≧Imrth) (step S147a).

[0167] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold value Imrth (|Imr|<Imrth) (step S147a; No), the process returns to the process of step S146.

[0168] When the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold value Imrth (|Imr|≧Imrth) (step S147a; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the left maximum steering angle θh_L_end in the EEPROM 1004 (step S143), and returns to the steering wheel position correction process shown in FIG. 4.

[0169] (Modification 6) FIG. 22 is a flowchart showing an example of a right maximum steering angle acquisition process according to Modification 6 of Embodiment 1. FIG. 23 is a flowchart showing an example of a left maximum steering angle acquisition process according to Modification 6 of Embodiment 1. Here, an example of acquiring the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end using the angular velocity ωr of the reaction force motor 61 will be described.

[0170] After the process of step S12 shown in FIG. 4, the ECU 50 executes the right maximum steering angle acquisition process shown in FIG. 22 (step S13).

[0171] In step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at a first angular velocity ωr1 so as to steer the steering wheel 1 to the right (step S131a), and determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is equal to or less than the angular velocity threshold value ωrth (|ωr|≦ωrth) (step S132b).

[0172] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold ωrth (|ωr|>ωrth) (step S132b; No), the process returns to step S131a.

[0173] When the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes equal to or less than the angular velocity threshold ωrth (step S132b; Yes), the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the left (step S134) until a predetermined time T has elapsed (step S135).

[0174] When the predetermined time T has elapsed (step S135; Yes), in step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at a second angular velocity ωr2 that is relatively slower than the first angular velocity ωr1 so as to steer the steering wheel 1 to the right (step S136), and determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is equal to or less than the angular velocity threshold value ωrth (|ωr|≦ωrth) (step S137b).

[0175] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold ωrth (|ωr|>ωrth) (step S137b; No), the process returns to step S136.

[0176] When the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes equal to or less than the angular velocity threshold ωrth (step S132b; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time in the EEPROM 1004 as the maximum right steering angle θh_R_end (step S133), and returns to the steering wheel position correction processing shown in Figure 4.

[0177] Next, the ECU 50 executes a left maximum steering angle acquisition process shown in FIG. 19 (step S14).

[0178] In step S14 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at a first angular velocity ωr1 so as to steer the steering wheel 1 to the left (step S141a), and determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is equal to or less than the angular velocity threshold value ωrth (|ωr|≦ωrth) (step S142b).

[0179] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold ωrth (|ωr|>ωrth) (step S142b; No), the process returns to step S141a.

[0180] When the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes equal to or less than the angular velocity threshold ωrth (step S142b; Yes), the ECU 50 drives the reaction force motor 61 so as to steer the steering wheel 1 to the right (step S144) until a predetermined time T has elapsed (step S145).

[0181] When the predetermined time T has elapsed (step S145; Yes), in step S14 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at a second angular velocity ωr2 that is relatively slower than the first angular velocity ωr1 so as to steer the steering wheel 1 to the left (step S146), and determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is equal to or less than the angular velocity threshold value ωrth (|ωr|≦ωrth) (step S147b).

[0182] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold value ωrth (|ωr|>ωrth) (step S147b; No), the process returns to step S146.

[0183] When the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes equal to or less than the angular velocity threshold ωrth (step S142b; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the left maximum steering angle θh_L_end in the EEPROM 1004 (step S143), and returns to the steering wheel position correction process shown in FIG. 4.

[0184] (Modification 7) FIG. 24 is a flowchart showing an example of the right maximum steering angle acquisition process according to Modification 7 of Embodiment 1. FIG. 25 is a flowchart showing an example of the left maximum steering angle acquisition process according to Modification 7 of Embodiment 1. Here, an example of acquiring the right maximum steering angle θh_R_end and the left maximum steering angle θh_L_end using the steering torque Ts detected by the torque sensor 10, the current value Imr of the reaction force motor 61, and the angular velocity ωr of the reaction force motor 61 will be described.

[0185] After the process of step S12 shown in FIG. 4, the ECU 50 executes the right maximum steering angle acquisition process shown in FIG. 18 (step S13).

[0186] In step S13 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at the first angular velocity ωr1 so as to steer the steering wheel 1 in the right direction (step S131a), and determines whether or not the absolute value |Ts| of the steering torque Ts is equal to or greater than the torque threshold Tth (|Ts|≧Tth) (step S132).

[0187] If the absolute value |Ts| of the steering torque Ts is less than the torque threshold Tth (|Ts|<Tth) (step S132; No), then subsequently, the ECU 50 determines whether or not the absolute value |Imr| of the current value Imr of the reaction force motor is equal to or greater than the current threshold Imrth (|Imr|≧Imrth) (step S132a).

[0188] If the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold value Imrth (|Imr| < Imrth) (step S132a; No), then subsequently, the ECU 50 determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is less than or equal to the angular velocity threshold value ωrth (|ωr| ≦ ωrth) (step S132b).

[0189] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold value ωrth (|ωr| > ωrth) (step S132b; No), the process returns to step S131a.

[0190] When the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold value Tth (|Ts| ≧ Tth) (step S132; Yes), when the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold value Imrth (|Imr| ≧ Imrth) (step S132a; Yes), or when the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes less than or equal to the angular velocity threshold value ωrth (step S132b; Yes), the ECU 50 drives the reaction force motor 61 to steer the steering wheel 1 to the left until a predetermined time T elapses (step S'135) (step S134).

[0191] When the predetermined time T elapses (step S135; Yes), the ECU 50 drives the reaction force motor 61 at a second angular velocity ωr2 that is relatively slower than the first angular velocity ωr1 to steer the steering wheel 1 to the right in step S13 shown in FIGURE 4 (step S136), and determines whether the absolute value |Ts| of the steering torque Ts is greater than or equal to the torque threshold value Tth (|Ts| ≧ Tth) (step S137).

[0192] If the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts| < Tth) (step S137; No), then subsequently, the ECU 50 determines whether the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold value Imrth (|Imr| ≧ Imrth) (step S137a).

[0193] If the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold value Imrth (|Imr| < Imrth) (step S137a; No), then subsequently, the ECU 50 determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is less than or equal to the angular velocity threshold value ωrth (|ωr| ≤ ωrth) (step S137b).

[0194] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold value ωrth (|ωr| > ωrth) (step S137b; No), the process returns to the process of step S136.

[0195] When the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold value Tth (|Ts| ≥ Tth) (step S137; Yes), when the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold value Imrth (|Imr| ≥ Imrth) (step S137a; Yes), or when the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes less than or equal to the angular velocity threshold value ωrth (step S137b; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the right maximum steering angle θh_R_end in the EEPROM 1004 (step S133), and returns to the steering wheel position correction process shown in FIG. 4.

[0196] Subsequently, the ECU 50 executes the left maximum steering angle acquisition process shown in FIG. 19 (step S14).

[0197] In step S14 shown in FIG. 4, the ECU 50 drives the reaction force motor 61 at the first angular velocity ωr1 so as to steer the steering wheel 1 in the left direction (step S141a), and determines whether the absolute value |Ts| of the steering torque Ts is greater than or equal to the torque threshold value Tth (|Ts| ≥ Tth) (step S142).

[0198] If the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts| < Tth) (step S142; No), then subsequently, the ECU 50 determines whether the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold value Imrth (|Imr| ≥ Imrth) (step S142a).

[0199] If the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold value Imrth (|Imr| < Imrth) (step S142a; No), then subsequently, the ECU 50 determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is less than or equal to the angular velocity threshold value ωrth (|ωr| ≤ ωrth) (step S142b).

[0200] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold value ωrth (|ωr| > ωrth) (step S142b; No), the process returns to step S141a.

[0201] If the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold value Tth (|Ts| ≥ Tth) (step S142; Yes), the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold value Imrth (|Imr| ≥ Imrth) (step S142a; Yes), or the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes less than or equal to the angular velocity threshold value ωrth (step S142b; Yes), the ECU 50 drives the reaction force motor 61 to steer the steering wheel 1 to the right direction until a predetermined time T elapses (step S145) (step S144).

[0202] When the predetermined time T elapses (step S145; Yes), the ECU 50 drives the reaction force motor 61 at a second angular velocity ωr2 that is relatively slower than the first angular velocity ωr1 to steer the steering wheel 1 to the left direction in step S14 shown in FIG. 4 (step S146), and determines whether the absolute value |Ts| of the steering torque Ts is greater than or equal to the torque threshold value Tth (|Ts| ≥ Tth) (step S147).

[0203] If the absolute value |Ts| of the steering torque Ts is less than the torque threshold value Tth (|Ts| < Tth) (step S147; No), then subsequently, the ECU 50 determines whether the absolute value |Imr| of the current value Imr of the reaction force motor 61 is greater than or equal to the current threshold value Imrth (|Imr| ≧ Imrth) (step S147a).

[0204] If the absolute value |Imr| of the current value Imr of the reaction force motor 61 is less than the current threshold value Imrth (|Imr| < Imrth) (step S147a; No), then subsequently, the ECU 50 determines whether the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is less than or equal to the angular velocity threshold value ωrth (|ωr| ≦ ωrth) (step S147b).

[0205] If the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 is greater than the angular velocity threshold value ωrth (|ωr| > ωrth) (step S147b; No), the process returns to step S146.

[0206] If the absolute value |Ts| of the steering torque Ts becomes greater than or equal to the torque threshold value Tth (|Ts| ≧ Tth) (step S147; Yes), the absolute value |Imr| of the current value Imr of the reaction force motor 61 becomes greater than or equal to the current threshold value Imrth (|Imr| ≧ Imrth) (step S147a; Yes), or the absolute value |ωr| of the angular velocity ωr of the reaction force motor 61 becomes less than or equal to the angular velocity threshold value ωrth (step S147b; Yes), the ECU 50 stores the current position θh_abs of the steering angle θh at that time as the left maximum steering angle θh_L_end in the EEPROM 1004 (step S143), and returns to the steering wheel position correction process shown in FIG. 4.

[0207] Thereby, if any one of the steering torque Ts detected by the torque sensor 10, the current value Imr of the reaction force motor 61, and the angular velocity ωr of the reaction force motor 61 is normal, the steering wheel position correction process can be executed.

[0208] The steering wheel position correction process according to the first embodiment described above corrects the neutral position θh_cen of the steering wheel 1, and can absorb the relative deviation between the current position θh_abs of the steering angle θh and the current position θt_abs of the turning angle θt, which is caused by some physical force acting on the steering wheel 1.

[0209] (Embodiment 2) In the first embodiment, the description is given of the steering wheel position correction process for correcting the neutral position θt_cen of the steering wheel 1. In the present embodiment, the description is given of the steered wheel position correction process for correcting the neutral position θt_cen of the steered wheels 8L, 8R.

[0210] The relationship between the steering angle θt and the motor angle θtm of the steering motor 71 is shown in the following equation (4): In equation (4), k2 is a coefficient given by the gear ratio of the gear 72.

[0211] θt=k2×θtm (4)

[0212] 1 detects the motor angle θtm of the steering motor 71, ECU 50 obtains the current positions of the steered wheels 8L, 8R using the above equation (4). Specifically, while the vehicle is traveling, ECU 50 calculates the current position θt_abs by adding up the time change Δθt of the steering angle θt to the previous value of the steering angle θt, and stores the calculated position in EEPROM 1004 sequentially.

[0213] In this case, for example, if some kind of physical external force acts on the steerable wheels 8L, 8R while the vehicle is stopped, a deviation may occur between the current positions θt_abs of the steerable wheels 8L, 8R stored in the EEPROM 1004 while the vehicle is running, and an error may occur when the process of obtaining the current positions of the steerable wheels 8L, 8R is started. Also, errors may accumulate while the vehicle is running, causing the neutral position θt_cen of the steerable wheels 8L, 8R to deviate.

[0214] Fig. 26 is a flowchart showing an example of steered wheel position correction processing according to the second embodiment. Fig. 27 is a flowchart showing an example of right maximum steering angle acquisition processing according to the second embodiment. Fig. 28 is a flowchart showing an example of left maximum steering angle acquisition processing according to the second embodiment. Fig. 29 is a diagram for explaining the operation in steered wheel position correction processing according to the second embodiment. Here, an example will be described in which the right maximum steering angle θt_R_end and the left maximum steering angle θt_L_end are acquired using the current value Imd (see Fig. 1) of the steering motor 71.

[0215] The steered wheel position correction process shown in Fig. 26 can be performed, for example, at the time of starting up the ECU 50. The timing of performing the steered wheel position correction process is not limited to the time of starting up the ECU 50, and may be, for example, performed before stopping the ECU 50.

[0216] Since it is cumbersome to perform the position correction process each time the ECU 50 is started or stopped, it is desirable that the steering wheel position correction process be performed by operating a button or touch panel (not shown) when the driver recognizes a discrepancy between the steering wheel 1 and the steering angle θt.

[0217] First, the ECU 50 initializes (N=0) a counter value N of the number of times the steered wheel position correction process is performed (step S21). A maximum value Nth of the number of times the steered wheel position correction process is performed is preset to, for example, 3.

[0218] Next, the ECU 50 increments the counter value N (N=N+1) of the number of times the steered wheel position correction process has been performed (step S22), and executes the right maximum steering angle acquisition process shown in FIG. 27 (step S23).

[0219] As shown in FIG. 29, in step S23 shown in FIG. 26, the ECU 50 drives the steering motor 71 so as to steer the steering wheels 8L and 8R to the right (step S231, (1) in FIG. 29), and determines whether or not the absolute value |Imd| of the current value Imd of the steering motor 71 is greater than or equal to a preset current threshold value Imdth (|Imd|≧Imdth) (step S232).

[0220] When the maximum steering angle θt_R_end or θt_L_end is reached, it abuts against a translational stopper that mechanically restricts the translational movement of the rack bar constituting the pinion rack mechanism 5, and the translational movement of the rack bar is restricted. In a state where the translational movement of the rack bar is restricted, a deviation occurs between the steering angle θt and the target steering angle. Therefore, the ECU 50 increases the current supplied to the steering motor 71 in an attempt to reduce this deviation. That is, by comparing the current value Imd supplied to the steering motor 71 with the current threshold value Imdth, the maximum steering angle θt_R_end or θt_L_end can be detected.

[0221] If the absolute value |Imd| of the current value Imd of the steering motor 71 is less than the current threshold value Imdth (|Imr|<Imdth) (step S232; No), the process returns to the process of step S231.

[0222] When the absolute value |Imd| of the current value Imd of the steering motor 71 becomes greater than or equal to the current threshold value Imdth (|Imd|≧Imdth) (step S232; Yes), the ECU 50 stores the current position θt_abs of the steering angle θt at that time as the right maximum steering angle θt_R_end in the EEPROM 1004 (step S233), and returns to the steering wheel position correction process shown in FIG. 26.

[0223] [[ID=​​​​As shown in FIG. 29, in step S24 shown in FIG. 26, the ECU 50 drives the steering motor 71 so as to steer the steering wheels 8L and 8R to the left (step S241, (2) in FIG. 29), and determines whether or not the absolute value |Imd| of the current value Imd of the steering motor 71 is greater than or equal to the current threshold value Imdth (|Imd|≧Imdth) (step S242).

[0225] When the absolute value |Imd| of the current value Imd of the steering motor 71 is equal to the current threshold value Imdth (|Imd|<Imdth) (step S242; No), the process returns to the process of step S241.

[0226] When the absolute value |Imd| of the current value Imd of the steering motor 71 becomes greater than or equal to the current threshold value Imdth (|Imd|≧Imdth) (step S242; Yes), the ECU 50 stores the current position θt_abs of the steering angle θt at that time as the left maximum steering angle θt_L_end in the EEPROM 1004 (step S243), and returns to the steering wheel position correction process shown in FIG. 26.

[0227] The ECU 50 determines whether or not the absolute value of the difference (|θt_R_end - θt_L_end|) between the right maximum steering angle θt_R_end acquired in step S23 and the left maximum steering angle θt_L_end acquired in step S24 is greater than or equal to the threshold value θtth (|θt_R_end - θt_L_end|≧θtth) (step S25). The threshold value θtth is preset based on the physical movable range of the steering wheels 8L and 8R. The threshold value θtth is defined by, for example, the following formula (5). In the following formula (5), θt_R_end(real) represents the physical right maximum steering angle of the steering wheels 8L and 8R, and θt_L_end(real) represents the physical left maximum steering angle of the steering wheels 8L and 8R.

[0228] θtth < |θt_R_end(real) - θt_L_end(real)| ··· (5)

[0229] Here, when the absolute value of the difference between the right maximum steering angle θt_R_end obtained in step S23 and the left maximum steering angle θt_L_end obtained in step S24 is less than the threshold θtth (|θt_R_end - θt_L_end| < θtth) (step S25; No), while the steering motor 71 is being driven (step S231 or step S241), it is considered that some physical external force has acted on the steering motor 71 and the absolute value |Imd| of the current value Imd of the steering motor 71 has become equal to or greater than the current threshold Imdth (step S232; Yes or step S242; Yes). In this case, the process proceeds to step S26, and it is determined whether the counter value N of the number of executions of the steering wheel position correction process is equal to or greater than the maximum value Nth of the number of executions of the steering wheel position correction process (N ≧ Nth) (step S26). If N < Nth (step S26; No), the process returns to the process of step S22 and the above-described process is retried. If N ≧ Nth (step S26; Yes), the steering wheel position correction process is interrupted.

[0230] When the absolute value of the difference (|θt_R_end - θt_L_end|) between the right maximum steering angle θt_R_end and the left maximum steering angle θt_L_end is equal to or greater than the threshold θtth (|θt_R_end - θt_L_end| ≧ θtth) (step S25; Yes), the right maximum steering angle θt_R_end obtained in step S23 and the left maximum steering angle θt_L_end obtained in step S24 can be respectively determined to be the physical right maximum steering angle of the steering wheels 8L, 8R and the physical left maximum steering angle of the steering wheels 8L, 8R that have been obtained. That is, the midpoint between the right maximum steering angle θt_R_end obtained in step S23 and the left maximum steering angle θt_L_end obtained in step S24 can be regarded as the neutral position θt_cen of the steering wheels 8L, 8R. The ECU 50 calculates the neutral position θt_cen of the steering wheels 8L, 8R using the following formula (6) (step S27).

[0231] θt_cen = θt_L_end + (θt_R_end - θt_L_end) / 2 ··· (6)

[0232] Here, the neutral position θt_cen of the steered wheels 8L, 8R may be offset to 0. In this case, the right maximum steering angle θt_R_end is a value obtained by offsetting the value acquired in step S23 by the neutral position θt_cen calculated by the above equation (6), and the left maximum steering angle θt_L_end is a value obtained by offsetting the value acquired in step S24 by the neutral position θt_cen calculated by the above equation (6).

[0233] Next, the ECU 50 calculates the target steering angle θt_tp (step S28). The target steering angle θt_tp may be, for example, the neutral position θt_cen of the steered wheels 8L, 8R, or a predetermined position corresponding to the current position θh_abs of the steering angle θh.

[0234] As shown in Fig. 29, ECU 50 drives steering motor 71 to steer steered wheels 8L, 8R to the right (step S29, (3) in Fig. 29) until the current position θt_abs of steered wheels 8L, 8R becomes equal to or greater than the target steering angle θt_tp (step S30; Yes). When the current position θt_abs of steered wheels 8L, 8R becomes equal to or greater than the target steering angle θt_tp, driving of steering motor 71 is stopped, so that the current position θt_abs and the target steering angle θt_tp can be made to match. In other words, the steered wheels 8L, 8R can be moved to the position of the target steering angle θt_tp.

[0235] Note that instead of driving the steering motor 71 to steer the steerable wheels 8L, 8R to the right until the current position θt_abs of the steerable wheels 8L, 8R becomes equal to or greater than the target steering angle θt_tp, the steering motor 71 may be driven to steer the steerable wheels 8L, 8R to the right until the current position θt_abs of the steerable wheels 8L, 8R becomes a value within a predetermined angle range including the target steering angle θt_tp. For example, if the target steering angle θt_tp calculated from the current position θh_abs of the steering angle θh is 60°, the steering motor 71 may be driven so that the steerable wheels 8L, 8R are steered to the right until the current position θt_abs of the steerable wheels 8L, 8R becomes within the range of 60±1°.

[0236] In short, the steered wheels 8L, 8R should be driven to a position that substantially matches the target steering angle θt_tp.

[0237] When the current position θt_abs of the steered wheels 8L, 8R becomes equal to or greater than the target steering angle θt_tp (step S30; Yes), the ECU 50 ends the steered wheel position correction process.

[0238] (Variation 1) Fig. 30 is a flowchart showing an example of right maximum steering angle acquisition processing according to Modification 1 of Embodiment 2. Fig. 31 is a flowchart showing an example of left maximum steering angle acquisition processing according to Modification 1 of Embodiment 2. Fig. 32 is a diagram illustrating the operation of steered wheel position correction processing according to Modification 1 of Embodiment 2. Here, an example will be described in which the right maximum steering angle θt_R_end and the left maximum steering angle θt_L_end are acquired using the angular velocity ωd of steering motor 71. The angular velocity ωd of steering motor 71 is obtained by time differentiating the motor angle θtm of steering motor 71 detected by angle sensor 73.

[0239] After the process of step S22 shown in FIG. 26, the ECU 50 executes the right maximum steering angle acquisition process shown in FIG. 30 (step S23).

[0240] As shown in FIG. 32, in step S23 shown in FIG. 26, the ECU 50 drives the steering motor 71 to steer the steered wheels 8L, 8R to the right (step S231, (1) in FIG. 32), and determines whether the absolute value |ωd| of the angular velocity ωd of the steering motor 71 is less than or equal to a predetermined angular velocity threshold value ωdth (|ωd|≦ωdth) (step S232b).

[0241] If the absolute value |ωd| of the angular velocity ωd of the steering motor 71 is greater than the angular velocity threshold value ωdth (|ωd|>ωdth) (step S232b; No), the process returns to step S231.

[0242] When the absolute value |ωd| of the angular velocity ωd of the steering motor 71 becomes equal to or less than the angular velocity threshold value ωdth (step S232b; Yes), the ECU 50 stores the current position θt_abs of the steering angle θt at that time in the EEPROM 1004 as the right maximum steering angle θt_R_end (step S233), and returns to the steered wheel position correction processing shown in FIG. 26.

[0243] Next, the ECU 50 executes a left maximum steering angle acquisition process shown in FIG. 31 (step S24).

[0244] As shown in FIG. 32, in step S24 shown in FIG. 26, the ECU 50 drives the steering motor 71 to steer the steered wheels 8L, 8R to the right (step S241, (2) in FIG. 32), and determines whether the absolute value |ωd| of the angular velocity ωd of the steering motor 71 is less than or equal to the angular velocity threshold value ωdth (|ωd|≦ωdth) (step S242b).

[0245] If the absolute value |ωd| of the angular velocity ωd of the steering motor 71 is greater than the angular velocity threshold value ωdth (|ωd|>ωdth) (step S242b; No), the process returns to step S241.

[0246] When the absolute value |ωd| of the angular velocity ωd of the steering motor 71 becomes equal to or less than the angular velocity threshold value ωdth (step S242b; Yes), the ECU 50 stores the current position θt_abs of the steering angle θt at that time in the EEPROM 1004 as the left maximum steering angle θt_L_end (step S243), and returns to the steered wheel position correction processing shown in FIG. 26.

[0247] (Variation 2) Fig. 33 is a flowchart showing an example of right maximum steering angle acquisition processing according to Modification 2 of Embodiment 2. Fig. 34 is a flowchart showing an example of left maximum steering angle acquisition processing according to Modification 2 of Embodiment 2. Here, an example will be described in which the current value Imd of steering motor 71 and the angular velocity ωd of steering motor 71 are used to acquire the right maximum steering angle θt_R_end and the left maximum steering angle θt_L_end.

[0248] After the process of step S22 shown in FIG. 26, the ECU 50 executes the right maximum steering angle acquisition process shown in FIG. 33 (step S23).

[0249] In step S23 shown in FIG. 26, the ECU 50 drives the steering motor 71 so as to steer the steering wheels 8L and 8R in the right direction (step S231), and determines whether or not the absolute value |Imd| of the current value Imd of the steering motor 71 is greater than or equal to the current threshold Imdth (|Imd|≧Imdth) (step S232a).

[0250] If the absolute value |Imd| of the current value Imd of the steering motor 71 is less than the current threshold Imdth (|Imd|<Imdth) (step S232a; No), then the ECU 50 subsequently determines whether or not the absolute value |ωd| of the angular velocity ωd of the steering motor 71 is less than or equal to the angular velocity threshold ωdth (|ωd|≦ωdth) (step S232b).

[0251] If the absolute value |ωd| of the angular velocity ωd of the steering motor 71 is greater than the angular velocity threshold ωdth (|ωd|>ωdth) (step S232b; No), the process returns to step S231.

[0252] When the absolute value |Imd| of the current value Imd of the steering motor 71 becomes greater than or equal to the current threshold Imdth (|Imd|≧Imdth) (step S232a; Yes), or when the absolute value |ωd| of the angular velocity ωd of the steering motor 71 becomes less than or equal to the angular velocity threshold ωdth (|ωd|≦ωdth) (step S232b; Yes), the ECU 50 stores the current position θt_abs of the steering angle θt at that time as the right maximum steering angle θt_R_end in the EEPROM 1004 (step S233), and returns to the steering wheel position correction process shown in FIG. 26.

[0253] Subsequently, the ECU 50 executes the left maximum steering angle acquisition process shown in FIG. 34 (step S24).

[0254] In step S24 shown in FIG. 26, the ECU 50 drives the steering motor 71 so as to steer the steering wheels 8L and 8R to the left (step S241), and determines whether or not the absolute value |Imd| of the current value Imd of the steering motor 71 is greater than or equal to the current threshold value Imdth (|Imd| ≧ Imdth) (step S242a).

[0255] If the absolute value |Imd| of the current value Imd of the steering motor 71 is less than the current threshold value Imdth (|Imd| < Imdth) (step S242a; No), then subsequently, the ECU 50 determines whether or not the absolute value |ωd| of the angular velocity ωd of the steering motor 71 is less than or equal to the angular velocity threshold value ωdth (|ωd| ≦ ωdth) (step S242b).

[0256] If the absolute value |ωd| of the angular velocity ωd of the steering motor 71 is greater than the angular velocity threshold value ωdth (|ωd| > ωdth) (step S242b; No), the process returns to step S241.

[0257] When the absolute value |Imd| of the current value Imd of the steering motor 71 becomes greater than or equal to the current threshold value Imdth (|Imd| ≧ Imdth) (step S242a; Yes), or when the absolute value |ωd| of the angular velocity ωd of the steering motor 71 becomes less than or equal to the angular velocity threshold value ωdth (|ωd| ≦ ωdth) (step S242b; Yes), the ECU 50 stores the current position θt_abs of the steering angle θt at that time as the left maximum steering angle θt_L_end in the EEPROM 1004 (step S243), and returns to the steering wheel position correction process shown in FIG. 26.

[0258] Thereby, if either one of the current value Imd of the steering motor 71 and the angular velocity ωd of the steering motor 71 is normal, the steering wheel position correction process can be executed.

[0259] The steered wheel position correction process according to the second embodiment described above corrects the neutral position θt_cen of the steered wheels 8L, 8R, and can absorb the relative deviation between the current position θt_abs of the steering angle θt and the current position θh_abs of the steering angle θh caused by some physical force acting on the steered wheels 8L, 8R.

[0260] In addition, if the configuration is equipped with a torque sensor that detects the steering torque of the steered wheels 8L, 8R, it is also possible to obtain the right maximum steering angle θt_R_end and the left maximum steering angle θt_L_end using the steering torque detected by the torque sensor.

[0261] (Embodiment 3) 35 and 36 are flowcharts showing an example of the position correction process according to the third embodiment.

[0262] 35, for example, the steering wheel position correction process (step S2) described in the second embodiment may be executed after the steering wheel position correction process (step S1) described in the first embodiment is executed. Alternatively, without being limited thereto, for example, the steering wheel position correction process (step S1) described in the first embodiment may be executed after the steering wheel position correction process (step S2) described in the second embodiment is executed.

[0263] Also, as shown in FIG. 36, for example, the steering wheel position correction process (step S1) described in the first embodiment and the steered wheel position correction process (step S2) described in the second embodiment may be executed in parallel.

[0264] The figures used above are conceptual diagrams for qualitatively explaining the present disclosure, and are not intended to be limiting. Furthermore, while the above-described embodiment is an example of a preferred implementation of the present disclosure, the present disclosure is not limited thereto, and various modifications can be made without departing from the spirit and scope of the present disclosure. [Explanation of symbols]

[0265] 1 handle 2 column axis 3 Reduction mechanism 5 Pinion rack mechanism 6a, 6b tie rod 7a, 7b Hub unit 8L,8R steering wheel 10 Torque sensor 11 Ignition key 12 Vehicle speed sensor 13 Battery 14 Steering angle sensor 50 Control Unit (ECU) 60 Reaction Device 61 Reaction motor 70 Drive Unit 71 Steering motor 72 gears 73 Angle Sensor 74 Angle Sensor 1001 CPU 1002 ROM 1003 RAM 1004 EEPROM 1005 Interface 1006 A / D converter 1007 PWM controller 1100 Control computer (MCU) Imd current value (steering motor) Imr Current value (reaction motor) Ts steering torque θh steering angle θh_abs Current position (steering angle) θh_cen Neutral position (handle) θh_L_end Maximum left steering angle θh_R_end Right side maximum steering angle θhm Motor angle (reaction motor) θt Steering angle θt_abs Current position (steering angle) θt_cen Neutral position (steering wheel) θt_L_end Left side maximum steering angle θt_R_end Right side maximum turning angle θtm Motor angle (steering motor) ωd Angular velocity (steering motor) ωr Angular velocity (reaction motor)

Claims

1. a reaction motor that applies a steering reaction force to the steering wheel; a steering motor that steers the steered wheels in response to steering of the steering wheel; a control unit that controls the reaction motor and the steering motor; Equipped with The control unit the reaction force motor is controlled to steer the steering wheel rightward, and when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold value and the current value of the reaction force motor is equal to or greater than a predetermined current threshold value, a right maximum steering angle is acquired; the reaction force motor is controlled to steer the steering wheel leftward, and when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold value and the current value of the reaction force motor is equal to or greater than a predetermined current threshold value, a left maximum steering angle is acquired; when an absolute value of a difference between the right maximum steering angle and the left maximum steering angle is equal to or greater than a first threshold value that is set in advance based on a physical movable range of the steering wheel, the midpoint between the right maximum steering angle and the left maximum steering angle is set as a neutral position of the steering wheel, When the absolute value of the difference between the right maximum steering angle and the left maximum steering angle is less than the first threshold value, the reaction force motor is controlled to steer the steering wheel rightward to obtain the right maximum steering angle again, and the reaction force motor is controlled to steer the steering wheel leftward to obtain the left maximum steering angle again. Vehicle steering device.

2. a reaction motor that applies a steering reaction force to the steering wheel; a steering motor that steers the steered wheels in response to steering of the steering wheel; a control unit that controls the reaction motor and the steering motor; Equipped with the steering motor is controlled to steer the steered wheels to the right, and when it is detected that a current value of the steering motor is equal to or greater than a predetermined current threshold, a right-side maximum steering angle is acquired; the steering motor is controlled to steer the steered wheels to the left, and when it is detected that a current value of the steering motor is equal to or greater than a predetermined current threshold, a left-side maximum steering angle is acquired; when a difference between the right maximum steering angle and the left maximum steering angle is equal to or greater than a second threshold value that is set in advance based on a physical movable range of the steered wheels, a midpoint between the right maximum steering angle and the left maximum steering angle is set as a neutral position of the steered wheels, When the difference between the right maximum steering angle and the left maximum steering angle is less than the second threshold value, the steering motor is controlled to steer the steered wheels to the right, thereby obtaining the right maximum steering angle again, and the steering motor is controlled to steer the steered wheels to the left, thereby obtaining the left maximum steering angle again. Vehicle steering device.

3. a reaction motor that applies a steering reaction force to the steering wheel; a steering motor that steers the steered wheels in response to steering of the steering wheel; a control unit that controls the reaction motor and the steering motor; Equipped with The control unit the reaction force motor is controlled to steer the steering wheel rightward, and when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold value and the current value of the reaction force motor is equal to or greater than a predetermined current threshold value, a right maximum steering angle is acquired; the reaction force motor is controlled to steer the steering wheel leftward, and when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold value and the current value of the reaction force motor is equal to or greater than a predetermined current threshold value, a left maximum steering angle is acquired; when an absolute value of a difference between the right maximum steering angle and the left maximum steering angle is equal to or greater than a first threshold value that is set in advance based on a physical movable range of the steering wheel, the midpoint between the right maximum steering angle and the left maximum steering angle is set as a neutral position of the steering wheel, when the absolute value of the difference between the right maximum steering angle and the left maximum steering angle is less than the first threshold value, the reaction force motor is controlled to steer the steering wheel to the right, thereby obtaining the right maximum steering angle again, and the reaction force motor is controlled to steer the steering wheel to the left, thereby obtaining the left maximum steering angle again; the steering motor is controlled to steer the steered wheels to the right, and when it is detected that a current value of the steering motor is equal to or greater than a predetermined current threshold, a right-side maximum steering angle is acquired; the steering motor is controlled to steer the steered wheels to the left, and when it is detected that a current value of the steering motor is equal to or greater than a predetermined current threshold, a left-side maximum steering angle is acquired; when a difference between the right maximum steering angle and the left maximum steering angle is equal to or greater than a second threshold value that is set in advance based on a physical movable range of the steered wheels, a midpoint between the right maximum steering angle and the left maximum steering angle is set as a neutral position of the steered wheels, When the difference between the right maximum steering angle and the left maximum steering angle is less than the second threshold value, the steering motor is controlled to steer the steered wheels to the right, thereby obtaining the right maximum steering angle again, and the steering motor is controlled to steer the steered wheels to the left, thereby obtaining the left maximum steering angle again. Vehicle steering device.

4. A method for adjusting a vehicle steering device including a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, a first step of controlling the reaction motor to steer the steering wheel rightward to obtain a maximum rightward steering angle; a second step of controlling the reaction motor to steer the steering wheel leftward to obtain a maximum left steering angle; a third step of setting a midpoint between the right maximum steering angle and the left maximum steering angle as a neutral position of the steering wheel; and In the first step, when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, or that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the right maximum steering angle is acquired; In the second step, when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, or the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the left maximum steering angle is acquired; in the first step, the reaction force motor is driven at a first angular velocity, and after detecting any one of the following: the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the reaction force motor is driven at a second angular velocity slower than the first angular velocity, and when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the right maximum steering angle is acquired; In the second step, the reaction force motor is driven at a first angular velocity, and after detecting any one of the following: the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the reaction force motor is driven at a second angular velocity slower than the first angular velocity, and the left maximum steering angle is acquired when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold. A method for adjusting a steering system for a vehicle.

5. a fourth step of controlling the reaction motor after acquiring the right maximum steering angle and the left maximum steering angle until the current position of the steering wheel becomes equal to or greater than a predetermined target steering angle; 5. The method for adjusting a steering system for a vehicle according to claim 4.

6. a fourth step of controlling the reaction motor after acquiring the right maximum steering angle and the left maximum steering angle until the current position of the steering wheel is within a predetermined angle range including a predetermined target steering angle; 5. The method for adjusting a steering system for a vehicle according to claim 4.

7. A method for adjusting a vehicle steering device including a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, a first step of controlling the reaction motor to steer the steering wheel rightward to obtain a maximum rightward steering angle; a second step of controlling the reaction motor to steer the steering wheel leftward to obtain a maximum left steering angle; a third step of setting a midpoint between the right maximum steering angle and the left maximum steering angle as a neutral position of the steering wheel; and In the first step, when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold and the current value of the reaction force motor is equal to or greater than a predetermined current threshold, the right maximum steering angle is acquired; In the second step, when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold and the current value of the reaction force motor is equal to or greater than a predetermined current threshold, the left maximum steering angle is acquired; In the third step, when an absolute value of a difference between the right maximum steering angle and the left maximum steering angle is equal to or greater than a first threshold value that is set in advance based on a physical movable range of the steering wheel, a midpoint between the right maximum steering angle and the left maximum steering angle is set as a neutral position of the steering wheel, If the absolute value of the difference between the right maximum steering angle and the left maximum steering angle is less than the first threshold value in the third step, the process returns to the first step and the second step. A method for adjusting a steering system for a vehicle.

8. A method for adjusting a vehicle steering device including a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, a first step of controlling the steering motor to steer the steered wheels to the right, thereby obtaining a maximum right-side steering angle; a second step of controlling the steering motor to steer the steered wheels to the left to obtain a maximum left steering angle; a third step of setting a midpoint between the right maximum steering angle and the left maximum steering angle as a neutral position of the steered wheels; and In the first step, when it is detected that the current value of the steering motor is equal to or greater than a predetermined current threshold, the right maximum steering angle is acquired; In the second step, when it is detected that the current value of the steering motor is equal to or greater than a predetermined current threshold, the left maximum steering angle is acquired; in the third step, when a difference between the right maximum steering angle and the left maximum steering angle is equal to or greater than a second threshold value that is set in advance based on a physical movable range of the steered wheels, a midpoint between the right maximum steering angle and the left maximum steering angle is set as a neutral position of the steered wheels; In the third step, when the difference between the right maximum steering angle and the left maximum steering angle is less than the second threshold value, the process returns to the first step and the second step. A method for adjusting a steering system for a vehicle.

9. A method for adjusting a vehicle steering device including a reaction motor that applies a steering reaction force to a steering wheel, a steering motor that steers steered wheels in response to steering of the steering wheel, and a control unit that controls the reaction motor and the steering motor, a first step of controlling the reaction motor to steer the steering wheel rightward to obtain a maximum rightward steering angle; a second step of controlling the reaction motor to steer the steering wheel leftward to obtain a maximum left steering angle; a third step of setting a midpoint between the right maximum steering angle and the left maximum steering angle as a neutral position of the steering wheel; a fourth step of controlling the steering motor to steer the steered wheels to the right to obtain a maximum right-side steering angle; a fifth step of controlling the steering motor to steer the steered wheels to the left to obtain a maximum left steering angle; a sixth step of setting a midpoint between the right maximum steering angle and the left maximum steering angle as a neutral position of the steered wheels; and In the first step, when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, that the current value of the reaction force motor is equal to or greater than a predetermined current threshold, or that the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the right maximum steering angle is acquired; In the second step, when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, or the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the left maximum steering angle is acquired; in the first step, the reaction force motor is driven at a first angular velocity, and after detecting any one of the following: the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the reaction force motor is driven at a second angular velocity slower than the first angular velocity, and when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the right maximum steering angle is acquired; In the second step, the reaction force motor is driven at a first angular velocity, and after detecting any one of the following: the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold, the reaction force motor is driven at a second angular velocity slower than the first angular velocity, and the left maximum steering angle is acquired when it is detected that the steering torque of the steering wheel is equal to or greater than a predetermined torque threshold, the current value of the reaction force motor is equal to or greater than a predetermined current threshold, and the angular velocity of the reaction force motor is equal to or less than a predetermined angular velocity threshold. A method for adjusting a steering system for a vehicle.

10. In the fourth step, when it is detected that either a current value of the steering motor is equal to or greater than a predetermined current threshold or an angular velocity of the steering motor is equal to or less than a predetermined angular velocity threshold, the right maximum steering angle is acquired; In the fifth step, when it is detected that the current value of the steering motor is equal to or greater than a predetermined current threshold and the angular velocity of the steering motor is equal to or less than a predetermined angular velocity threshold, the left maximum steering angle is acquired.

10. The method for adjusting a vehicle steering system according to claim 9.

Images