Steering control device, steering control method, and steer-by-wire system

Abstract

A steering control device, a steering control method, and a steering-by-wire system according to the present invention, in a steering-by-wire system having a first actuator for applying a torque to a steering operation input member and a second actuator for applying a steering force to a wheel, when the system is turned on, the steering force is applied to the wheel by the first actuator, and the steering force is applied to the wheel by the second actuator. When the amount of deviation of the steering angle of the wheel with respect to the operation position of the steering operation input member is equal to or greater than a permissible amount, the first actuator is controlled so that the amount of deviation becomes smaller when the vehicle speed is equal to or less than a threshold value. When the vehicle speed is greater than the threshold value, the second actuator is controlled so that the deviation amount becomes smaller. As a result, it is possible to suppress adverse effects on vehicle maintenance and vehicle travel by control that matches the operation position and the steering angle.

Description

Technical Field

[0001] The invention relates to a steering control device, a steering control method and a wire-controlled steering system. Background Art

[0002] The steering device disclosed in Patent Document 1 includes a motor that applies a virtual steering reaction force to a steering wheel.

[0003] Furthermore, when the ignition switch of the steering device is off, if there is a deviation between the steering angle of the steering wheel and the rotational position of the steering wheel, the ECU drives the motor to apply a motor driving force to the steering wheel in a direction opposite to the rotational direction of the steering wheel.

[0004] Thereby, the steering wheel rotates so that the rotational position thereof coincides with the steering angle of the steered wheel.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: (Japanese) Patent Publication No. 2006-321434 Summary of the invention

[0008] Technical problem to be solved by the invention

[0009] However, in a vehicle equipped with a steer-by-wire system, there may be a situation where the steering angle of the wheel deviates from the operating position of a steering input component such as a steering wheel. As a positioning control to reduce the deviation, there is a control for moving the operating position of the steering input component to a position corresponding to the steering angle of the wheel, and conversely, a control for moving the steering angle of the wheel to an angle corresponding to the operating position of the steering input component.

[0010] However, if the two positioning controls are not differentiated according to the vehicle speed condition in the positioning control when the steer-by-wire system is turned on, the vehicle maintenance work may be affected and the vehicle behavior may be unexpected to the driver of the vehicle.

[0011] The present invention is made in view of previous actual situations, and aims to provide a steering control device, a steering control method and a wire-controlled steering system that can suppress the adverse effects of controlling the operating position of a steering operation input component to be consistent with the steering angle of a wheel on vehicle maintenance and vehicle driving.

[0012] Technical solutions for solving technical problems

[0013] In one embodiment of the present invention, in a steer-by-wire system having a first actuator for applying torque to a steering operation input component and a second actuator for applying steering force to wheels of a vehicle, when the system is turned on, if the deviation of the steering angle of the wheel relative to the operating position of the steering operation input component is greater than an allowable amount, a control signal is output to the first actuator in such a manner as to reduce the deviation when the vehicle speed is below a threshold value, and a control signal is output to the second actuator in such a manner as to reduce the deviation when the vehicle speed is greater than the threshold value.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to suppress the adverse effects of the control for matching the operation position of the steering input member with the steering angle of the wheels on vehicle maintenance and vehicle travel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of a vehicle equipped with a steer-by-wire system.

[0017] Figure 2 This is a diagram showing state transitions in positioning control.

[0018] Figure 3 1 and 2 are diagrams showing the transition of the control state of the reaction motor and the transition of the control state of the steering motor.

[0019] Figure 4 This is a flowchart showing the flow of control of the steer-by-wire system.

[0020] Figure 5 It is a diagram showing a state of alignment performed by the first alignment control.

[0021] Figure 6 It is a diagram showing a state of alignment performed by the first alignment control.

[0022] Figure 7 It is a diagram showing a state of positioning performed by the second positioning control.

[0023] Figure 8 It is a diagram showing a state of positioning performed by the second positioning control.

[0024] Fig. 9 It is a diagram showing a state of positioning performed by the second positioning control when the vehicle starts.

[0025] Fig.10 This is a diagram showing a situation where the positioning is performed manually.

[0026] Fig.11 This is a flowchart showing the processing contents in the alignment mode.

[0027] Fig.12 : is a line graph showing the relationship between the speed limit and the vehicle speed in the second positioning control.

[0028] Fig.13 This is a flowchart showing the processing contents in the alignment mode for distinguishing between the parking state and the running state based on the accelerator operation amount.

[0029] Fig.14 This is a diagram showing a steer-by-wire system in which a steering operation input device includes a steering control device.

[0030] Fig.15 The diagram shows a steer-by-wire system in which a steering device includes a steering control device. DETAILED DESCRIPTION

[0031] Hereinafter, embodiments of a steering control device, a steering control method, and a steer-by-wire system according to the present invention will be described with reference to the accompanying drawings.

[0032] Figure 1 1 is a schematic diagram showing one embodiment of a vehicle 100 equipped with a steer-by-wire system 200 .

[0033] The vehicle 100 is a four-wheeled vehicle including a pair of left and right front wheels 101 , 102 and a pair of left and right rear wheels 103 , 104 .

[0034] The steer-by-wire system 200 includes a steering operation input device 300 that inputs a steering operation of the driver of the vehicle 100 via a steering wheel 310 , a steering device 400 that includes a steering actuator that applies a steering force to the wheels (front wheels 101 , 102 ) of the vehicle 100 , and a steering control device 500 .

[0035] Furthermore, in the steer-by-wire system 200 , the steering operation input device 300 and the steering device 400 are mechanically separated.

[0036] In other words, in the steer-by-wire system 200 , the steering wheel 310 and the front wheels 101 , 102 are mechanically separated.

[0037] The steering input device 300 includes a steering wheel 310 , a steering shaft 320 , a reaction force motor 330 , and an operation angle sensor 340 .

[0038] The steering wheel 310 is a steering operation input member operated by a driver of the vehicle 100 .

[0039] The reaction force motor 330 is a reaction force actuator (first actuator) provided to pseudo-apply a steering reaction torque to the steering wheel 310 .

[0040] That is, the steering operation input device 300 is a device that inputs the driver's steering operation via the steering wheel 310 , and includes a reaction force motor 330 that applies a steering reaction torque to the steering wheel 310 .

[0041] The operation angle sensor 340 detects the rotation angle of the steering shaft 320 as the operation angle θ (in other words, the operation position) of the steering wheel 310 .

[0042] Specifically, the operation angle sensor 340 detects the neutral position of the steering wheel 310 as the operation angle θ=0 degrees.

[0043] Furthermore, for example, when the steering wheel 310 is operated to the left from the neutral position, the operation angle sensor 340 detects the operation angle θ as a positive angle, and detects the operation angle θ as a negative angle when the steering wheel 310 is operated to the right from the neutral position.

[0044] The steering device 400 includes a steering motor 410 as a steering actuator (second actuator), a steering mechanism 420 that changes the steering angle δ of the front wheels 101 , 102 by the steering torque generated by the steering motor 410 , and a steering angle sensor 430 that detects the steering angle δ of the front wheels 101 , 102 .

[0045] The steering mechanism 420 is a mechanism that changes the steering angle δ of the front wheels 101 and 102 by converting the rotational motion of the steering motor 410 into the linear motion of a rack bar using a rack and pinion system, for example.

[0046] The steering angle sensor 430 is a sensor that detects the steering angle δ of the front wheels 101 and 102 by detecting the rotational position of the steering motor 410 or the position of the rack bar of the steering mechanism 420 .

[0047] Specifically, the steering angle sensor 430 detects the neutral position of the front wheels 101 , 102 as the steering angle δ=0 degrees.

[0048] Furthermore, the steering angle sensor 430 detects the steering angle δ as a positive angle when the front wheels 101 , 102 are steered leftward from the neutral position, and detects the steering angle δ as a negative angle when the front wheels 101 , 102 are steered rightward from the neutral position, for example.

[0049] It should be noted that the neutral position of the front wheels 101 and 102 is a position where the front wheels 101 and 102 are not turned to either the left or right and the vehicle 100 is moving straight ahead.

[0050] The neutral position of the steering wheel 310 is a position where the steering wheel 310 is not operated to either the left or right direction and the front wheels 101 and 102 are in the neutral position.

[0051] The steering control device 500 is an electronic control device including an MCU (Micro Controller Unit) 510 , and controls the operation of the steer-by-wire system 200 .

[0052] It should be noted that MCU510 can be renamed as a microcomputer, a processor, a processing device, a computing device, etc.

[0053] Furthermore, the MCU 510 obtains a control signal for the reaction force motor 330 and a control signal for the steering motor 410 by performing calculation processing on various signals obtained from the outside, and outputs the obtained control signals.

[0054] That is, the MCU 510 has a function as a control unit that outputs control signals to the reaction force motor 330 and the steering motor 410 , in other words, has a function as a control unit that executes a steering control method.

[0055] Here, the steering control device 500 may include a pre-driver, an inverter, and the like for controlling energization of the reaction force motor 330 and energization of the steering motor 410 .

[0056] Furthermore, it is possible to provide a system including a drive circuit including a pre-driver and an inverter, etc., separately from the steering control device 500 .

[0057] The vehicle 100 includes a start switch 650 such as a power switch or an ignition switch for starting various systems of the vehicle 100 , and the steering control device 500 obtains an on / off signal of the start switch 650 .

[0058] The system activated by the start switch 650 includes the steer-by-wire system 200. Then, the steer-by-wire system 200 is powered on and activated by turning on the start switch 650, and enters the system ON state.

[0059] Furthermore, the vehicle 100 includes wheel speed sensors 621 to 624 for detecting wheel speeds WS1 to WS4 which are the rotation speeds of the wheels 101 to 104 , respectively.

[0060] MCU510 obtains the signals output by the wheel speed sensors 621~624 indicating the physical quantities related to the wheel speeds WS1~WS4 (or the signals indicating the physical quantities related to the vehicle speed VS obtained based on the outputs of the wheel speed sensors 621~624), the signals output by the operating angle sensor 340 indicating the physical quantities related to the operating angle θ, the signals output by the steering angle sensor 430 indicating the physical quantities related to the steering angle δ, etc.

[0061] Furthermore, MCU 510 calculates steering angle command value δtg which is a target value of steering angle δ based on information on operation angle θ of steering wheel 310 .

[0062] Furthermore, the MCU 510 obtains a control signal based on a deviation between the steering angle δ detected by the steering angle sensor 430 and the steering angle command value δtg, and outputs the obtained control signal to the steering motor 410 .

[0063] Then, the MCU 510 calculates a reaction torque command value TRtg which is a target value of the reaction torque TR based on information such as the vehicle speed VS obtained from the wheel speeds WS1 to WS4 and the operation angle θ of the steering wheel 310 .

[0064] It should be noted that the MCU 510 can obtain wheel speed WS1 to WS4 signals from the wheel speed sensors 621 to 624 to obtain the vehicle speed VS, and other electronic control devices can obtain information on the vehicle speed VS obtained based on the wheel speed WS1 to WS4 signals via the vehicle network.

[0065] Furthermore, the MCU 510 outputs a control signal based on the reaction torque command value TRtg to the reaction motor 330 .

[0066] In this way, the MCU 510 controls the operation of the steer-by-wire system 200 by controlling the steering force applied to the front wheels 101 , 102 and the reaction torque applied to the steering wheel 310 .

[0067] However, in steer-by-wire system 200 , steering wheel 310 and front wheels 101 , 102 are mechanically separated, so there is a case where the operation position of steering wheel 310 and steering angle δ of front wheels 101 , 102 are statically deviated.

[0068] Therefore, when the system is turned on, if the deviation AD of the steering angle δ of the front wheels 101 and 102 relative to the operating angle θ of the steering wheel 310 is greater than the allowable amount TD, in order to reduce the deviation AD, the MCU510 implements a positioning control that actively changes the operating angle θ or the steering angle δ through the actuator.

[0069] It should be noted that the deviation amount AD is an error between the actual steering angle δ and the steering angle command value δtg uniquely determined based on the operation angle θ of the steering wheel 310 .

[0070] Furthermore, when the MCU 510 actively changes the operation angle θ during the positioning control, the reaction motor 330 generates a rotational driving force for rotating the steering wheel 310 to a position corresponding to the steering angle δ.

[0071] By performing this positioning control and performing the positioning, the steering angle δ is controlled to correspond to the operation position of the steering wheel 310 , thereby improving the steering operability of the driver.

[0072] Here, the MCU 510 determines which of the operation angle θ and the steering angle δ is to be actively changed in the positioning control based on the physical quantity related to the vehicle speed VS.

[0073] In other words, MCU510 switches to implement, according to the physical quantity related to the vehicle speed VS, either a positioning control (hereinafter referred to as the first positioning control) for actively changing the position of the steering wheel 310 through the reaction motor 330 or a positioning control (hereinafter referred to as the second positioning control) for actively changing the steering angle δ of the front wheels 101 and 102 through the steering motor 410.

[0074] Hereinafter, the reason why the MCU 510 switches between the first positioning control and the second positioning control according to the condition of the vehicle speed VS will be described.

[0075] Here, it is assumed that the second positioning control is performed to actively change the steering angle δ (in other words, the orientation of the tires) while the vehicle 100 is parked.

[0076] For example, when the vehicle 100 is parked in a repair shop and maintenance work is being performed on the suspension or tires of the front wheels 101 and 102, the start switch 650 such as the ignition switch IGN-SW is turned on and the system is started. If the second positioning control is started at this time, the maintenance work may not be performed smoothly and safely due to unexpected changes in the orientation of the tires.

[0077] Furthermore, when the user of vehicle 100 turns on the start switch 650 to start the positioning control while vehicle 100 is parked, the tire orientation may unexpectedly change, causing the tire to interfere with a movable object located near the steering wheels, i.e., the front wheels 101, 102, resulting in unexpected movement of the movable object or the movable object being sandwiched between a fixed object such as a wall and the tire.

[0078] Concerns when the second positioning control is performed when the vehicle 100 is parked can be avoided by adopting the first positioning control that actively changes the position of the steering wheel 310 .

[0079] However, if the vehicle 100 starts with the steering wheel 310 being steered by the driver before the alignment by the first alignment control is completed, the first alignment control wants to make the operating position of the steering wheel 310 consistent with the steering angle δ. Therefore, the vehicle 100 moves in a state where the operating position of the steering wheel 310 deviates from the steering angle δ, which may cause the vehicle to behave in a manner unexpected by the driver.

[0080] Therefore, the steering control device 500 uses the first positioning control and the second positioning control separately according to the condition of the vehicle speed VS, thereby suppressing the positioning control when the system is turned on from causing adverse effects on vehicle maintenance and vehicle driving.

[0081] That is, a state in which the vehicle 100 is being maintained in a repair shop and a state in which the vehicle 100 is parked are both considered to be the parked state of the vehicle 100 .

[0082] Furthermore, if the first alignment control is used to align the vehicle 100 in the parked state, the orientation of the tires does not change, thereby preventing hindrance to maintenance work on the suspension, etc., and preventing movable objects present next to the vehicle 100 from being crushed or caught by the tires during parking.

[0083] On the other hand, if the second alignment control is used to align the vehicle 100 while it is in the driving state after it starts, as long as the alignment is based on the second control mode, the steering angle δ can be made consistent with the operating angle θ (in other words, the orientation of the tire is made consistent with the operating position of the steering wheel 310), thereby preventing the vehicle 100 from moving in a direction unexpected by the driver.

[0084] Therefore, when the steering control device 500 performs the positioning control when the system is turned on, the vehicle speed VS is compared with the threshold value VSTH for distinguishing and determining the positioning control.

[0085] Furthermore, the steering control device 500 selects the first positioning control when the vehicle speed VS is equal to or lower than the threshold value VSTH, and selects the second positioning control when the vehicle speed VS is higher than the threshold value VSTH.

[0086] Here, the threshold VSTH is set to 0 km / h or an extremely low vehicle speed. Therefore, a state where the vehicle speed VS is equal to or lower than the threshold VSTH corresponds to a stopped state of the vehicle 100, and a state where the vehicle speed VS is higher than the threshold VSTH corresponds to a running state of the vehicle 100.

[0087] That is, when the system is turned on, the steering control device 500 performs the first positioning control when the vehicle 100 is parked and the vehicle speed VS is equal to or lower than the threshold VSTH, and performs the second positioning control when the vehicle 100 is running and the vehicle speed VS is higher than the threshold VSTH.

[0088] Figure 2 1 is a diagram showing state transitions in the positioning control performed by the steering control device 500 .

[0089] and, Figure 3 It means Figure 2 The control states of the steering operation input device 300 and the steering device 400 in each state are shown.

[0090] Figure 2 The control state includes a first state which is a non-control state at an early stage after startup, a second state in which a first positioning control is implemented, a third state in which a normal steering control is implemented, and a fourth state in which a second positioning control is implemented.

[0091] When the start switch 650 is turned on and the steer-by-wire system 200 is turned on, that is, in the initial state immediately after the steering control device 500 is started, the steering control device 500 is in the first state.

[0092] The first state is a state in which the drive control of the reaction force motor 330 and the steering motor 410 is stopped, in other words, a non-control state of the reaction force motor 330 and the steering motor 410 .

[0093] In the first state, the steering control device 500 obtains a deviation AD [deg] between the steering angle δ of the front wheels 101 , 102 and the steering angle command value δtg based on the operation angle θ of the steering wheel 310 , and compares the obtained deviation AD with the allowable amount TD.

[0094] Then, when the vehicle 100 is in the stopped state where the deviation amount AD is equal to or greater than the allowable amount TD and the vehicle speed VS is equal to or less than the threshold value VSTH, the steering control device 500 transitions to the second state.

[0095] It should be noted that the deviation amount AD is the absolute value of the deviation angle.

[0096] The second state is a state in which the first positioning control is performed.

[0097] Here, the steering control device 500 controls the rotational driving force applied to the steering wheel 310 by the reaction motor 330 so that the operation angle θ of the steering wheel 310 changes to a position corresponding to the steering angle δ of the front wheels 101 , 102 .

[0098] Furthermore, the steering control device 500 keeps the steering motor 410 in the drive stop state (in other words, the non-control state) during the first positioning control.

[0099] It should be noted that the steering control device 500 limits the torque applied to the steering wheel 310 by the reaction force motor 330 and the rotation speed of the steering wheel 310 in the first positioning control.

[0100] Specifically, the steering control device 500 limits the rotation torque applied by the reaction force motor 330 to a degree that the driver can operate the steering wheel 310 against the rotation torque applied by the reaction force motor 330 .

[0101] Furthermore, the steering control device 500 limits the rotation speed of the steering wheel 310 to a level that does not cause the steering wheel 310 to automatically rotate and interfere with the driver's hands or the like, thereby preventing the driver from receiving an impact.

[0102] Furthermore, when the first positioning control is executed, the steering control device 500 activates the warning device 640 provided in the vehicle 100 to notify the driver of the vehicle 100 of the execution of the positioning control (or a minor abnormality of the steer-by-wire system 200 ).

[0103] The warning device 640 is a warning light, a liquid crystal display device, a sound guidance device, etc.

[0104] The warning by the warning device 640 allows the driver to recognize that the positioning control is being performed, and can suppress panic even if the steering wheel 310 starts to rotate automatically.

[0105] Furthermore, if the driver postpones the start operation of the vehicle 100 due to the warning issued by the warning device 640, it helps to complete the alignment in the parking state.

[0106] In this way, if the first positioning control is implemented when the vehicle 100 is parked, the operating angle θ of the steering wheel 310 is changed while maintaining the steering angle δ of the front wheels 101 and 102. Therefore, even if the positioning control is performed during maintenance of the driving system in a repair shop, the steering angle δ of the front wheels 101 and 102 will not change unexpectedly, and maintenance operations can be carried out smoothly and safely.

[0107] Furthermore, when the user of the vehicle 100 parks the vehicle 100 , even if the vehicle 100 is aligned, the steering angle δ of the front wheels 101 , 102 does not change, so that interference between the tires and movable objects near the front wheels 101 , 102 can be avoided.

[0108] On the other hand, when the steering control device 500 determines in the first state that the deviation AD is less than the allowable amount TD, that is, when the steering angle δ of the front wheels 101, 102 is an angle corresponding to the operating angle θ of the steering wheel 310 and no deviation requiring corrective action is generated, the device changes to the third state regardless of the vehicle speed VS (in other words, regardless of whether the vehicle 100 is parked or moving).

[0109] The third state is a normal steering state in which normal control of the reaction force motor 330 and the steering motor 410 is performed.

[0110] That is, in the third state, the steering control device 500 controls the reaction force motor 330 in such a manner as to simulate the generation of a steering reaction force through the reaction force motor 330 , and controls the steering motor 410 in such a manner that the steering angle δ of the front wheels 101 , 102 becomes an angle corresponding to the operating angle θ of the steering wheel 310 .

[0111] Furthermore, the steering control device 500 performs the first alignment control in the second state, and when the deviation amount AD becomes smaller than the allowable amount TD, that is, when the alignment performed by the first alignment control is completed, it changes to the third state and performs normal control of the reaction force motor 330 and the steering motor 410.

[0112] In this way, the steering control device 500 implements the first positioning control when the vehicle 100 is in a parked state and when the deviation AD is lower than the allowable amount TD, it transitions to a normal steering control state. In the normal steering control state, a steering reaction torque is applied to the steering wheel 310 through the reaction motor 330, and a steering force based on the operation information of the steering wheel 310, i.e., the operation angle θ, is applied to the front wheels 101 and 102 through the steering motor 410.

[0113] Furthermore, when the steering control device 500 detects the start of the vehicle 100 while the first positioning control is being executed in the second state and before the positioning by the first positioning control is completed, that is, before the deviation AD falls below the allowable amount TD, the steering control device 500 transitions to the fourth state.

[0114] It should be noted that the detection of the start of the vehicle 100 is the detection of the vehicle speed VS being higher than the threshold value VSTH, in other words, the detection of the transition from the parking state to the running state of the vehicle 100 or the detection of the vehicle speed signal input.

[0115] The fourth state is a state in which the second positioning control is performed.

[0116] Here, the steering control device 500 controls the steering force applied by the steering motor 410 to the front wheels 101 , 102 so that the steering angle δ of the front wheels 101 , 102 quickly changes to an angle corresponding to the operation angle θ of the steering wheel 310 .

[0117] Furthermore, the steering control device 500 simulates the generation of a steering reaction force by the reaction force motor 330 in the second positioning control in the fourth state.

[0118] That is, when the vehicle 100 starts moving during the first positioning control, the steering control device 500 switches the positioning control from the first positioning control to the second positioning control.

[0119] Therefore, when the vehicle 100 starts moving while the driver is steering the steering wheel 310 , the steering angle δ of the front wheels 101 , 102 is changed to match the position of the steering wheel 310 , thereby suppressing the occurrence of vehicle behavior unexpected by the driver.

[0120] Furthermore, the steering control device 500 applies a reaction torque to the steering wheel 310 by the reaction motor 330 during the second positioning control, so that it is possible to suppress the position of the steering wheel 310 from randomly moving, and stabilize the maneuverability of the vehicle 100 when starting.

[0121] Here, when the steering control device 500 performs the second positioning control, the steering control device 500 also operates the warning device 640 in the same manner as when the first positioning control is performed.

[0122] When the deviation amount AD is smaller than the allowable amount TD by performing the second positioning control in the fourth state, that is, when the positioning by the second positioning control is completed, the steering control device 500 shifts to the third state and performs normal control of the reaction force motor 330 and the steering motor 410 .

[0123] That is, when the deviation AD is lower than the allowable amount TD by implementing the second positioning control under the driving state of the vehicle 100, the steering control device 500 transitions to the normal steering control state, in which a reaction torque is applied to the steering wheel 310 by the reaction motor 330, and a steering force based on the operating angle θ of the steering wheel 310 is applied to the front wheels 101 and 102 by the steering motor 410.

[0124] When the steering control device 500 determines in the first state (specifically, the initial non-control state after startup) that the deviation amount AD is greater than the allowable amount TD and the vehicle 100 is in a running state where the vehicle speed VS is greater than the threshold VSTH, it transitions to the fourth state and implements the second positioning control.

[0125] That is, when the vehicle 100 is moving at an early stage after startup, the steering control device 500 does not perform the first positioning control but directly performs the second positioning control.

[0126] Figure 4 It means that it contains Figure 2 and Figure 3 This is a flowchart illustrating the flow of control of the steer-by-wire system 200 by the steering control device 500 including the positioning control.

[0127] Figure 4 The flowchart separately describes the control process of the steering operation input device 300 and the control process of the steering device 400, and each control process includes an initial process, a positioning mode, a normal driving mode, and an end mode.

[0128] When the start switch 650 such as the ignition switch IGN-SW is turned on and the system is started, the steering control device 500 executes initial processing for each of the steering operation input device 300 and the steering device 400 .

[0129] Then, the steering control device 500 enters the alignment mode, and transitions to any one of the first state, the second state, the third state, and the fourth state according to the conditions of the deviation amount AD and the vehicle speed VS.

[0130] As described above, the first state is a non-control state at the beginning after startup, the second state is a state in which the first alignment control is implemented, the third state is a state in which normal steering control is implemented due to completion of alignment, and the fourth state is a state in which the second alignment control is implemented.

[0131] Furthermore, the steering operation input device 300 is in the non-control state in the first state, but is in the position control state in which the reaction force motor 330 is controlled so as to have the operation angle θ corresponding to the steering angle δ in the second state.

[0132] In addition, the steering operation input device 300 is in a torque control state in which a steering reaction torque is applied to the steering wheel 310 by the reaction motor in the third state and the fourth state.

[0133] On the other hand, the steering device 400 is in the non-controlled state in the first and second states, but is in the position controlled state in which the steering motor 410 is controlled so as to obtain the steering angle δ corresponding to the operation angle θ in the third and fourth states.

[0134] Furthermore, in the alignment mode, the steering control device 500 operates the warning device 640 , such as lighting of the warning light, in any state other than the third state.

[0135] It should be noted that the steering control device 500 does not implement positioning control in the first state, but since it is at a branch point as to whether to implement positioning, the warning device 640 is operated in the first state, and continues to operate when changing from the first state to the second state or the fourth state.

[0136] Furthermore, when the steering control device 500 completes the alignment in the second state or the fourth state and changes to the third state, or changes from the first state to the third state, the steering control device 500 enters the normal driving mode and stops the operation of the warning device 640.

[0137] Then, when the start switch 650 such as the ignition switch IGN-SW is turned off, the steering control device 500 enters the end mode, performs a predetermined end process, and then turns off.

[0138] Figure 5 and Figure 6 The following are examples of how the steering angle δ and the operation angle θ change during the first positioning control.

[0139] Figure 5The figure shows a situation where the steering angle δ of the front wheels 101, 102 deviates to the left from the straight-ahead position (in other words, the neutral position) and the operating angle θ of the steering wheel 310 is near the neutral position, and the operating angle θ is made consistent with the steering angle δ by the first alignment control.

[0140] In this case, when the ignition switch IGN-SW serving as the start switch 650 is turned on and the system is turned on, the steering control device 500 uses the reaction motor 330 to rotate the steering wheel 310 in the counterclockwise direction, so that the operating angle θ of the steering wheel 310 moves to a position corresponding to the steering angle δ, that is, a position rotated to the left compared to the neutral position.

[0141] While the steering wheel 310 is being rotated by the rotational driving force of the reaction motor 330 , the steering control device 500 keeps the steering motor 410 in a non-control state and keeps the steering angle δ at the original angle.

[0142] Furthermore, while the first alignment control is being performed, in other words, while the operation angle θ of the steering wheel 310 is actively changed, the steering control device 500 operates the warning device 640 such as a warning light to warn the driver of the vehicle 100 that the alignment is in progress.

[0143] Figure 6 The figure shows a situation where the steering angle δ of the front wheels 101 and 102 is near the straight-ahead position and the operating angle θ of the steering wheel 310 deviates to the left from the neutral position, and the operating angle θ is made consistent with the steering angle δ by the first alignment control.

[0144] In this case, when the ignition switch IGN-SW as the start switch 650 is turned on and the system is turned on, the steering control device 500 uses the reaction motor 330 to rotate the steering wheel 310 in the clockwise direction, so that the operating angle θ of the steering wheel 310 moves to a position corresponding to the steering angle δ, that is, a neutral position.

[0145] Here, the steering control device 500 also keeps the steering motor 410 in the non-control state during the positioning period, keeps the steering angle δ at the initial angle, that is, at the neutral position, and activates the warning device 640 .

[0146] The first positioning control is implemented when the vehicle 100 is parked, so the direction of the front wheels 101, 102 will not change unexpectedly when the vehicle 100 is parked. Even if the system is turned on during maintenance work or when there are movable objects near the front wheels 101, 102, it can suppress adverse effects on the maintenance work and the movable objects.

[0147] on the other hand, Figure 7 and Figure 8The following are examples of how the steering angle δ and the operation angle θ change during the second positioning control.

[0148] Figure 7 The figure shows a situation where the steering angle δ of the front wheels 101, 102 deviates to the left from the straight-ahead position (in other words, the neutral position) and the operating angle θ of the steering wheel 310 is near the neutral position, and the steering angle δ is made consistent with the operating angle θ by the second alignment control.

[0149] In this case, the steering control device 500 controls the steering force generated by the steering motor 410 to change the steering angle δ of the front wheels 101 and 102 to a neutral position.

[0150] and, Figure 8 The figure shows a situation where the steering angle δ of the front wheels 101 and 102 is near the straight-ahead position and the operating angle θ of the steering wheel 310 deviates to the left from the neutral position, and the operating angle θ is made consistent with the steering angle δ by the second alignment control.

[0151] In this case, the steering control device 500 controls the steering force generated by the steering motor 410 to change the steering angle δ of the front wheels 101 , 102 from the neutral position to an angle offset to the left side corresponding to the operation angle θ of the steering wheel 310 .

[0152] like Figure 7 and Figure 8 As shown, the second alignment control actively changes the steering angle δ of the front wheels 101 and 102 . Therefore, when implemented in a parked state, it may have an adverse effect on the maintenance work of the front wheels 101 and 102 and movable objects near the front wheels 101 and 102 .

[0153] However, the steering control device 500 implements the first positioning control when the vehicle 100 is in the parked state, and switches to the second positioning control when it is in the driving state, so that the positioning control in the parked state can prevent the maintenance work and movable objects near the front wheels 101 and 102 from having adverse effects.

[0154] Furthermore, the steering control device 500 performs the second positioning control while the vehicle 100 is traveling, and quickly corrects the steering angle δ to the steering angle θ corresponding to the operation angle θ of the steering wheel 310 , thereby suppressing the occurrence of vehicle behavior that is unexpected by the driver.

[0155] Fig. 9 The diagram shows a state where the steering angle δ is changed by the second position alignment control when the vehicle 100 starts moving from a state where the deviation amount AD is generated between the operation angle θ and the steering angle δ and the driver steers the steering wheel 310 .

[0156] Here, the steering wheel 310 is in a substantially neutral position and the front wheels 101 , 102 are turned to the left compared to the straight ahead position.

[0157] Then, the steering control device 500 changes to the second positioning control, i.e., the fourth state, according to the start of the vehicle 100, i.e., the transition from the parking state to the driving state, so as to control the steering force of the steering motor 410 in such a way that the steering angle δ of the front wheels 101, 102 is quickly changed to the straight-ahead position.

[0158] This can prevent the vehicle 100 from turning left against the driver's intention to keep the steering wheel 310 at the neutral position and move the vehicle 100 straight forward.

[0159] In addition, the steering control device 500 limits the rotation torque of the reaction force motor 330 to a degree that the driver can overcome the rotation torque applied by the reaction force motor 330 and operate the steering wheel 310 as described above during the first positioning control.

[0160] Therefore, in the first positioning control, intervention by the driver in changing the operation angle θ is permitted, and the driver can perform positioning manually.

[0161] Fig.10 It shows the situation where the manual alignment is performed in the second state of implementing the first alignment control.

[0162] Fig.10 The manual positioning is shown starting from a state where the steering wheel 310 is in the vicinity of the neutral position and the steering angle δ of the front wheels 101 and 102 is directed to the left side relative to the neutral position.

[0163] The vehicle 100 is in a stopped state and the first positioning control is performed, and the reaction motor 330 applies a rotational driving force to the steering wheel 310 . However, at this time, the driver operates the steering wheel 310 to the left, thereby enabling manual positioning.

[0164] Here, when the alignment is completed, the warning device 640 is stopped (for example, the warning light is turned off), so that the driver can recognize that the alignment is completed and stop the rotation operation of the steering wheel 310 when the operation angle θ corresponding to the steering angle δ is reached.

[0165] Then, the positioning is completed and the second state in which the first positioning control is implemented is shifted to the third state in which the normal control is restored. Thus, the reaction force motor 330 generates a reaction force to the driver's operation on the steering wheel 310, thereby restricting the driver's excessive steering operation.

[0166] If the vehicle 100 starts during manual positioning, the vehicle 100 switches to the fourth state, that is, the second positioning control, and the steering motor 410 generates a steering force such that the steering angle δ of the front wheels 101 , 102 matches the operation angle θ of the steering wheel 310 .

[0167] In addition, the steering control device 500 can transition from the second state (first position control) to the fourth state (second position control) according to the vehicle speed VS as described above, and can transition from the second state (first position control) to the fourth state (second position control) according to the switching of the gear position (in other words, the driving mode) of the automatic transmission constituting the power transmission system of the vehicle 100.

[0168] When the driver starts vehicle 100 from a stopped state (specifically, moves forward or backward), the driver performs a shift operation to change the gear position of the automatic transmission from a parking range P or a neutral range N to a driving range such as a forward range D or a reverse range R.

[0169] Therefore, when the steering control device 500 performs a shift operation from the parking gear P or the neutral gear N to the forward gear D or the reverse gear R, etc., it regards the shift operation as a preparation for starting, and changes from the second state (first alignment control) to the fourth state (second alignment control) without waiting for the actual start.

[0170] Thus, when the vehicle 100 starts in the middle of the first positioning control, the start timing of the second positioning control to match the steering angle δ with the operation angle θ is advanced, thereby accelerating the correction of the deviation and more stably suppressing the occurrence of vehicle behavior unexpected by the driver.

[0171] Furthermore, the steering control device 500 may include the duration of the first positioning control as a condition for transitioning from the second state (first positioning control) to the fourth state (second positioning control).

[0172] For example, the maximum time required for alignment based on the first alignment control can be estimated based on the assumed maximum deviation amount. If the first alignment control is continued beyond the maximum time, it can be estimated that some abnormality prevents alignment of actively moving the operation position of the steering wheel 310.

[0173] Then, when the duration of the first positioning control exceeds the set time, the steering control device 500 determines that the positioning by the first positioning control cannot be performed, and shifts to the fourth state (second positioning control).

[0174] Thus, although the first positioning control cannot be used for positioning, the reaction force motor 330 is prevented from continuously driving to generate a rotational driving force and causing the reaction force motor 330 or a driving circuit of the reaction force motor 330 to overheat.

[0175] Furthermore, although the first positioning control cannot be performed, the deviation amount AD can be reduced in advance before the vehicle 100 starts, thereby suppressing the occurrence of vehicle behavior that is unexpected by the driver.

[0176] Fig.11 The flowchart shows the process flow in the alignment mode when the shifting of the automatic transmission gear and the duration of the first alignment control are added as conditions for transitioning from the second state (first alignment control) to the fourth state (second alignment control).

[0177] When the steering control device 500 is activated by the system being turned on by turning on the start switch 650 , it is first determined in step S701 whether the deviation amount AD is equal to or larger than the allowable amount TD.

[0178] Here, when the deviation amount AD is smaller than the allowable amount TD and the deviation amount AD is not so large as to require a positioning process, the steering control device 500 proceeds to step S702 .

[0179] The steering control device 500 performs normal control of the reaction force motor 330 and the steering motor 410 in step S702 .

[0180] In other words, the steering control device 500 transitions from the first state (non-control state) to the third state (normal steering control) in step S702.

[0181] On the other hand, when the deviation amount AD is equal to or larger than the allowable amount TD and the positioning control is required, the steering control device 500 proceeds to step S703 .

[0182] In step S703 , the steering control device 500 compares the vehicle speed VS with the threshold value VSTH to thereby determine whether the vehicle 100 is in a stopped state or a running state.

[0183] Then, when the steering control device 500 determines that the vehicle speed VS is equal to or less than the threshold value VSTH and the vehicle 100 is in the parked state, the process proceeds to step S704 .

[0184] The steering control device 500 performs the first positioning control in step S704. In other words, the steering control device 500 changes from the first state (non-control state) to the second state (first positioning control) in step S704.

[0185] The steering control device 500 that has shifted to the second state (first alignment control) determines in the next step S705 whether the deviation amount AD has become smaller than the allowable amount TD, that is, whether the alignment has been completed.

[0186] Then, when the deviation amount AD becomes smaller than the allowable amount TD as a result of the first positioning control, the steering control device 500 proceeds to step S702.

[0187] In step S702, the steering control device 500 performs normal control of the reaction force motor 330 and the steering motor 410. In other words, in step S702, the steering control device 500 changes from the second state (first positioning control) to the third state (normal steering control).

[0188] On the other hand, when the deviation amount AD is maintained at or above the allowable amount TD, the steering control device 500 proceeds to step S706.

[0189] In step S706 , the steering control device 500 determines whether the vehicle 100 has transitioned from the parking state to the running state by determining whether the vehicle speed VS is equal to or lower than the threshold value VSTH.

[0190] Here, when the vehicle speed VS is higher than the threshold value VSTH and it is determined that the vehicle 100 has changed from the parking state to the running state, the steering control device 500 proceeds to step S709 and performs the second positioning control.

[0191] In other words, when the steering control device 500 detects that the vehicle 100 has started in the second state in which the first positioning control is being performed, the steering control device 500 changes from the second state (first positioning control) to the fourth state (second positioning control).

[0192] Then, when the steering control device 500 determines that the vehicle 100 is maintained in the parked state because the vehicle speed VS is equal to or lower than the threshold value VSTH, the process proceeds to step S707.

[0193] In step S707 , the steering control device 500 obtains a signal from the shift position sensor 630 that detects the shift position (driving mode) of the automatic transmission of the vehicle 100 , and determines whether the shift position has been changed from the parking position P or the neutral position N to the forward gear D or the reverse gear R.

[0194] Then, when the steering control device 500 detects a change from the parking range P or the neutral range N to the drive range D or the reverse range R, the process proceeds to step S709 to implement the second positioning control.

[0195] In other words, when the steering control device 500 detects a change from the parking range P or the neutral range N to the drive range D or the reverse range R, the steering control device 500 changes from the second state (the first alignment control) to the fourth state (the second alignment control).

[0196] That is, when a change is made from the parking range P or the neutral range N to the drive range D or the reverse range R, there is a high possibility that the driver will start the vehicle 100 thereafter.

[0197] Then, when the shift from the parking range P or the neutral range N to the drive range D or the reverse range R is performed, the steering control device 500 estimates that the vehicle 100 will start thereafter, and switches from the first positioning control to the second positioning control without waiting for the actual start of the vehicle 100 .

[0198] On the other hand, when the steering control device 500 does not detect the change from the parking range P or the neutral range N to the drive range D or the reverse range R, the process proceeds to step S708.

[0199] In step S708 , the steering control device 500 determines whether the duration T1 during which the first positioning control is continuously performed is equal to or longer than a predetermined time TTH.

[0200] Then, when the duration T1 is longer than the predetermined time TTH, that is, when the time expected to complete the alignment has passed but the alignment by the first alignment control has not been completed, the steering control device 500 proceeds to step S709 and performs the second alignment control.

[0201] Thus, when the first alignment control continues for the predetermined time TTH but the alignment is not completed, the steering control device 500 transitions from the second state (first alignment control) to the fourth state (second alignment control) even if the vehicle is kept parked.

[0202] On the other hand, when the duration T1 is shorter than the predetermined time TTH, the steering control device 500 returns to step S704 and continues the first positioning control (second state).

[0203] Furthermore, when the steering control device 500 performs the second positioning control, it is determined in step S710 whether the deviation amount AD becomes smaller than the allowable amount TD.

[0204] Then, when the deviation amount AD becomes smaller than the allowable amount TD due to the second position alignment control, the steering control device 500 proceeds to step S702 to perform normal control of the reaction force motor 330 and the steering motor 410 .

[0205] In other words, when the deviation amount AD becomes smaller than the allowable amount TD due to the second positioning control, the steering control device 500 transitions from the fourth state (second positioning control) to the third state (normal steering control).

[0206] On the other hand, when the deviation amount AD is maintained at or above the allowable amount TD, the steering control device 500 returns to step S709 and continues the second positioning control.

[0207] In the second positioning control, the steering control device 500 increases the rotation speed (operating speed) of the steering motor 410 as the vehicle speed VS is higher (in other words, as the physical quantity related to the vehicle speed is larger), thereby alleviating the driver's feeling of operational abnormality after starting.

[0208] For example, the steering control device 500 changes the speed limit (upper limit speed) in the control of the steering motor 410 in the second alignment control according to the vehicle speed VS. As a result, the higher the vehicle speed VS, the faster the rotation speed of the steering motor 410, i.e., the steering speed, is made. The higher the vehicle speed VS, the faster the alignment can be completed.

[0209] Fig.12 2 is a diagram showing one form of the relationship between the speed limit of the steering motor 410 and the vehicle speed VS in the second positioning control.

[0210] exist Fig.12 In the characteristic example, in the speed range of the vehicle speed VS from 0 km / h to 1 km / h, the speed limit VSL is maintained at the first speed limit VSL1.

[0211] Furthermore, in the speed range of 1 km / h to 3 km / h of the vehicle speed VS, the speed limit VSL gradually increases from the first speed limit VSL1 to the second speed limit VSL2 ( VSL2 > VSL1 ) as the vehicle speed VS increases.

[0212] Then, in the speed range where the vehicle speed VS is 3 km / h or higher, the speed limit VSL is maintained at the second speed limit VSL2.

[0213] The steering control device 500 performs the second alignment control according to Fig.12 The characteristics shown set the speed limit VSL according to the detected value of the vehicle speed VS, and drive control is performed on the steering motor 410 so that the rotation speed of the steering motor 410 does not exceed the speed limit VSL.

[0214] Here, the steering control device 500 makes the speed limit VSL higher as the vehicle speed VS increases, thereby suppressing the generation of noise caused by the sudden change in the direction of the front wheels 101 and 102 in the extremely low speed range just after starting, and speeding up the correction of the deviation amount AD when the vehicle speed VS becomes higher, thereby suppressing the occurrence of vehicle behavior unexpected by the driver.

[0215] Furthermore, the steering control device 500 can switch between the first position control and the second position control according to the accelerator operation amount which is a physical quantity related to the vehicle speed VS instead of the vehicle speed VS.

[0216] In other words, the steering control device 500 can use a physical quantity related to the accelerator operation amount instead of the vehicle speed VS as a state quantity of the vehicle 100 used to determine whether the vehicle 100 is in a stopped state or a running state.

[0217] In this case, the steering control device 500 acquires the physical quantity related to the accelerator operation amount AC directly from the accelerator operation amount sensor 660 that detects the accelerator operation amount AC or acquires the physical quantity related to the accelerator operation amount AC via the in-vehicle network.

[0218] Then, the steering control device 500 compares the acquired accelerator operation amount AC with the threshold value ACTH.

[0219] Here, threshold value ACTH corresponds to a value that accelerator operation amount AC does not exceed when vehicle 100 is stopped but exceeds when vehicle 100 is running.

[0220] Then, when the physical quantity related to the accelerator operation amount AC is equal to or less than the threshold value ACTH and it can be estimated that the vehicle 100 is in the stopped state, the steering control device 500 performs the first positioning control.

[0221] Furthermore, when the physical quantity related to the accelerator operation amount AC is larger than the threshold value ACTH and it can be estimated that the vehicle 100 is in the running state, the steering control device 500 performs the second positioning control.

[0222] Fig.13 The flowchart shows the flow of processing in the alignment mode to which processing for distinguishing between a parking state and a running state is applied based on the accelerator operation amount AC.

[0223] It should be noted that Fig.13 The flowchart is relative to Fig.11 , only the processing contents in step S703A and step S706A are different, and the same processing is performed in the other steps. Fig.11 The same process as the flowchart.

[0224] Therefore, the processing contents in step S703A and step S706A are described, and the description of the processing contents in other steps is omitted.

[0225] In step S703A, the steering control device 500 determines whether the accelerator operation amount AC is equal to or less than a threshold value ACTH.

[0226] Then, when the steering control device 500 determines in step S703A that the accelerator operation amount AC is below the threshold value ACTH and the vehicle 100 is in a parked state, it enters step S704; when it determines that the accelerator operation amount AC is greater than the threshold value ACTH and the vehicle 100 is in a driving state, it enters step S709.

[0227] Similarly, in step S706A, the steering control device 500 determines whether the accelerator operation amount AC is equal to or less than the threshold value ACTH.

[0228] Then, the steering control device 500 proceeds to step S707 when it is determined in step S706A that the accelerator operation amount AC is equal to or less than the threshold value ACTH, and proceeds to step S709 when it is determined that the accelerator operation amount AC is greater than the threshold value ACTH.

[0229] If the steering control device 500 determines the parking state and the driving state based on the accelerator operation amount AC instead of the vehicle speed VS, it can improve the switching response from the first positioning control to the second positioning control accompanying the start of the vehicle 100, and can more stably suppress the occurrence of vehicle behavior unexpected by the driver.

[0230] in addition, Figure 1 The illustrated steer-by-wire system 200 includes the steering operation input device 300 , the steering device 400 , and the steering control device 500 , respectively. However, the steering operation input device 300 or the steering device 400 may be integrally provided with the steering control device 500 .

[0231] It should be noted that the fact that the steering operation input device 300 or the steering device 400 is integrally provided with the steering control device 500 means that the steering operation input device and the steering control device 500, or the steering device 400 and the steering control device 500, constitute one unit.

[0232] Fig.14 The steer-by-wire system 200 is shown in which the steering operation input device 300 is provided with the steering control device 500 .

[0233] It should be noted that in Fig.14 In the steer-by-wire system 200 shown in FIG. 1 , the steering operation input device 300 includes the steering control device 500. Figure 1 The steer-by-wire system 200 shown is different, but other solutions are similar to Figure 1 The same as above, so the detailed description of each element is omitted.

[0234] Fig.14 The steer-by-wire system 200 is configured by assembling a steering operation input device 300 including a steering control device 500 and a steering device 400 in a vehicle 100 .

[0235] Moreover, the steering control device 500 of the steering operation input device 300 outputs the control signal of the reaction motor 330 and the control signal of the steering motor 410 according to the transition of the aforementioned first state (non-control state in the initial stage after startup), the second state (first alignment control), the third state (normal steering control), and the fourth state (second alignment control).

[0236] and, Fig.15 The steering device 400 is shown as a steer-by-wire system 200 including a steering control device 500 .

[0237] It should be noted that in Fig.15 In the steer-by-wire system 200 shown in FIG. 1 , the steering device 400 includes a steering control device 500. Figure 1 The steer-by-wire system 200 shown is different, but other solutions are similar to Figure 1 The same as above, so the detailed description of each element is omitted.

[0238] Fig.15 The steer-by-wire system 200 is configured by assembling a steering device 400 including a steering control device 500 and a steering operation input device 300 in a vehicle 100 .

[0239] Moreover, the steering control device 500 of the steering device 400 outputs the control signal of the reaction motor 330 and the control signal of the steering motor 410 according to the transition of the aforementioned first state (non-controlled state in the initial stage after startup), the second state (first alignment control), the third state (normal steering control), and the fourth state (second alignment control).

[0240] The technical ideas described in the above embodiments can be used in combination as appropriate unless there is any contradiction.

[0241] Furthermore, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious to those skilled in the art that various modifications can be adopted based on the basic technical concept and teachings of the present invention.

[0242] The trigger for starting the steer-by-wire system 200 is not limited to turning on the start switch, and may be, for example, vehicle occupancy detection, door unlocking, etc.

[0243] Furthermore, the steer-by-wire system 200 may include a backup mechanism capable of mechanically coupling the steering wheel 310 and the front wheels 101 , 102 using a clutch or the like.

[0244] In addition, the steering control device 500 can implement two discrimination processes: a discrimination process of the parking state and the driving state based on the vehicle speed VS and a discrimination process of the parking state and the driving state based on the accelerator operation amount AC. When a transition to the driving state is detected in any discrimination process, the second state (first alignment control) is changed to the fourth state (second alignment control).

[0245] In this case, the steering control device 500 changes from the second state (first position control) to the fourth state (second position control) when the accelerator operation amount AC is equal to or less than the threshold value ACTH but the traveling state is detected based on the vehicle speed VS.

[0246] In contrast, when the vehicle speed VS is equal to or lower than the threshold value VSTH but the running state is detected based on the accelerator operation amount AC, the steering control device 500 shifts from the second state (first position control) to the fourth state (second position control).

[0247] According to the above configuration, when the vehicle 100 starts moving from a stopped state on a downhill slope by releasing the brake, the vehicle 100 is switched to the second positioning control based on the increase in the vehicle speed VS, thereby suppressing the occurrence of vehicle behavior unexpected by the driver.

[0248] Furthermore, when the vehicle 100 starts to move due to a normal accelerator operation, the accelerator operation amount AC increases before the vehicle speed VS increases. Therefore, the transition to the fourth state (second positioning control) can be performed with good response to the start of the vehicle 100 .

[0249] Furthermore, the steering control device 500 may perform a transition from the second state (first positioning control) to the fourth state (second positioning control) based on the release of the parking brake.

[0250] This is because when the parking brake is released, similar to when the gear position is changed from the parking range P or the neutral range N to the drive range D or the reverse range R, it is possible to estimate the subsequent start of the vehicle 100 .

[0251] In addition, the steering control device 500 may be changed from the second state (first alignment control) to the fourth state (second alignment control) when the parking brake is released and the gear is shifted to the forward gear D or the reverse gear R.

[0252] According to the above configuration, the estimation accuracy of the start of the vehicle 100 is increased, and the transition from the second state (first positioning control) to the fourth state (second positioning control) can be performed more appropriately.

[0253] Description of Reference Numerals

[0254] 100…vehicle, 101, 102…front wheels, 200…steer-by-wire system, 300…steering operation input device, 310…steering wheel (steering operation input component), 330…reaction motor (first actuator), 400…steering device, 410…steering motor (second actuator), 500…steering control device, 510…MCU (control unit).

Claims

1. A steering control device, provided in a vehicle having a steer-by-wire system, the steer-by-wire system comprising a steering operation input device and a steering device, the steering operation input device receiving a driver's steering operation via a steering operation input component and comprising a first actuator applying a torque to the steering operation input component, the steering device comprising a second actuator applying a steering force to a wheel of the vehicle, the steering control device comprising a control unit outputting a control signal to the first actuator and the second actuator, characterized in that: For the control unit, When the system is turned on, a physical quantity related to the vehicle speed, a physical quantity related to the operation position of the steering operation input component, and a physical quantity related to the steering angle of the wheel are obtained. When the deviation of the steering angle from the operating position is greater than the allowable amount, When the physical quantity related to the vehicle speed is equal to or less than a threshold value, a control signal is output to the first actuator so as to reduce the deviation amount. When the physical quantity related to the vehicle speed is larger than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount.

2. The steering control device according to claim 1, wherein: The control unit obtains an on / off signal of a start switch of the vehicle, and regards when the start switch of the vehicle is turned on as when the system is turned on.

3. The steering control device according to claim 1, wherein: For the control unit, By comparing the physical quantity related to the vehicle speed with the threshold value, it is determined whether the vehicle is in a parked state or a running state. outputting a control signal to the first actuator so as to reduce the deviation amount when the vehicle is parked, When the vehicle is in a running state, a control signal is output to the second actuator so as to reduce the deviation amount.

4. The steering control device according to claim 3, wherein: For the control unit, When the deviation amount is less than the allowable amount in a parked state of the vehicle, the first actuator applies a reaction torque to the steering input member, and the second actuator applies a steering force based on operation information input to the steering input device to the wheels.

5. The steering control device according to claim 3, wherein: For the control unit, When a control signal is output to the second actuator so as to reduce the deviation amount in the running state of the vehicle, a reaction torque is applied to the steering operation input member by the first actuator.

6. The steering control device according to claim 5, wherein: For the control unit, When the deviation amount is lower than the allowable amount in the running state of the vehicle, the first actuator applies a reaction torque to the steering input member, and the second actuator applies a steering force based on operation information input to the steering input device to the wheels.

7. The steering control device according to claim 3, wherein: For the control unit, When a control signal is output to the first actuator in a manner that reduces the deviation amount when the vehicle is in a parked state, intervention based on the driver's change of the operating position is allowed, and when the deviation amount is lower than the allowable amount, a reaction torque is applied to the steering operation input component through the first actuator.

8. The steering control device according to claim 3, wherein: For the control unit, When the control signal is output to the first actuator in a manner that reduces the deviation amount in a parked state of the vehicle, when the driving mode of the automatic transmission of the vehicle is changed from a parking gear or a neutral gear to a forward gear or a reverse gear, The state is switched to output a control signal to the second actuator so that the deviation amount becomes smaller.

9. The steering control device according to claim 3, wherein: For the control unit, When a control signal is output to the second actuator so as to reduce the deviation amount in the running state of the vehicle, the operating speed of the second actuator is increased as the physical quantity related to the vehicle speed increases.

10. The steering control device according to claim 1, wherein: For the control unit, When a control signal is output to the first actuator or the second actuator so as to reduce the deviation amount, a warning device provided in the vehicle is activated.

11. The steering control device according to claim 1, wherein: For the control unit, obtaining a physical quantity related to an accelerator operation amount of the vehicle as a physical quantity related to the vehicle speed, outputting a control signal to the first actuator so as to reduce the deviation amount when the physical amount related to the accelerator operation amount is equal to or less than a threshold value, When the physical quantity related to the accelerator operation amount is larger than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount.

12. The steering control device according to claim 1, wherein: For the control unit, When the first actuator is continuously operated for a set time but the deviation amount is not less than the allowable amount, output of the control signal to the first actuator is stopped.

13. The steering control device according to claim 12, wherein: For the control unit, After the output of the control signal to the first actuator is stopped, a control signal is output to the second actuator so as to reduce the deviation amount.

14. The steering control device according to claim 13, wherein: For the control unit, When the control signal is output to the second actuator after the output of the control signal to the first actuator is stopped, a reaction torque is applied to the steering operation input member by the first actuator.

15. A steering control method, executed by a control unit provided in a vehicle having a steer-by-wire system, the steer-by-wire system comprising a steering operation input device and a steering device, the steering operation input device receiving a driver's steering operation via a steering operation input component and comprising a first actuator applying a torque to the steering operation input component, the steering device comprising a second actuator applying a steering force to a wheel of the vehicle, characterized in that: When the system is turned on, obtaining a physical quantity related to the vehicle speed, a physical quantity related to the operation position of the steering operation input member, and a physical quantity related to the steering angle of the wheel, When the deviation of the steering angle from the operating position is greater than the allowable amount, outputting a control signal to the first actuator so as to reduce the deviation amount when the physical quantity related to the vehicle speed is equal to or less than a threshold value, When the physical quantity related to the vehicle speed is larger than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount.

16. A steer-by-wire system, installed on a vehicle, characterized in that: have: a steering operation input device that receives a driver's steering operation via a steering operation input member and includes a first actuator that applies torque to the steering operation input member; a steering device having a second actuator for applying a steering force to a wheel of the vehicle; a control unit that outputs a control signal to the first actuator and the second actuator, For the control unit, When the system is turned on, obtaining a physical quantity related to the vehicle speed, a physical quantity related to the operation position of the steering operation input member, and a physical quantity related to the steering angle of the wheel, When the deviation of the steering angle from the operating position is greater than the allowable amount, outputting a control signal to the first actuator so as to reduce the deviation amount when the physical quantity related to the vehicle speed is equal to or less than a threshold value, When the physical quantity related to the vehicle speed is larger than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount.

17. A steering control device provided in a steering device of a steer-by-wire system, the steer-by-wire system comprising a steering operation input device and the steering device, the steering operation input device receiving a driver's steering operation via a steering operation input component and comprising a first actuator applying a torque to the steering operation input component, the steering device comprising a second actuator applying a steering force to a wheel of a vehicle, characterized in that: The steering control device includes a control unit that outputs control signals to the first actuator and the second actuator. For the control unit, When the system is turned on, obtaining a physical quantity related to the vehicle speed, a physical quantity related to the operation position of the steering operation input member, and a physical quantity related to the steering angle of the wheel, When the deviation of the steering angle from the operating position is greater than the allowable amount, outputting a control signal to the first actuator so as to reduce the deviation amount when the physical quantity related to the vehicle speed is equal to or less than a threshold value, When the physical quantity related to the vehicle speed is larger than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount.

18. A steering control device provided in an operation input device of a steer-by-wire system, the steer-by-wire system comprising the steering operation input device and a steering device, the steering operation input device receiving a driver's steering operation via a steering operation input component and comprising a first actuator applying a torque to the steering operation input component, the steering device comprising a second actuator applying a steering force to a wheel of a vehicle, characterized in that: The steering control device includes a control unit that outputs control signals to the first actuator and the second actuator. For the control unit, When the system is turned on, obtaining a physical quantity related to the vehicle speed, a physical quantity related to the operation position of the steering operation input member, and a physical quantity related to the steering angle of the wheel, When the deviation of the steering angle from the operating position is greater than the allowable amount, outputting a control signal to the first actuator so as to reduce the deviation amount when the physical quantity related to the vehicle speed is equal to or less than a threshold value, When the physical quantity related to the vehicle speed is larger than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount.

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