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

Abstract

The present invention pertains to a steering control device, a steering control method, and a steer-by-wire system. In one embodiment thereof, the steer-by-wire system has a first actuator that applies torque to a steering operation input member and a second actuator that applies steering force to wheels. If a deviation amount of the steering angle of the wheels relative to the operation position of the steering operation input member is not less than an acceptable amount when the system has been turned on, the first actuator is controlled such that the deviation amount decreases when the vehicle speed is not more than a threshold, and the second actuator is controlled such that the deviation amount decreases when the vehicle speed is more than the threshold. Therefore, it is possible to prevent control for adjustment of the operation position and the steering angle from adversely affecting on vehicle maintenance or vehicle travel.

Description

[Technical Field]

[0001] The present invention relates to a steering control device, a steering control method, and a steer-by-wire system. [Background technology]

[0002] The steering device of Patent Document 1 includes a motor that applies a virtual steering reaction force to the steering wheel. When the ignition switch is off, the steering device causes the ECU to drive the motor when there is a discrepancy between the steering angle of the steered wheels and the rotational position of the steering wheel, and the motor's driving force is applied to the steering wheel in the opposite direction to the rotational direction of the steering wheel. This causes the steering wheel to rotate so that its rotational position coincides with the steering angle of the steered wheels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-321434 Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle equipped with a steer-by-wire system, the steering angle of the wheels may deviate from the operating position of a steering operation input member such as a steering wheel. Positioning control to reduce such deviation includes control to move the operating position of the steering operation input member to a position that corresponds to the steering angle of the wheels, and conversely, control to move the steering angle of the wheels to an angle that corresponds to the operating position of the steering operation input member. However, when the steer-by-wire system is turned on, if the two alignment controls are not separated according to the vehicle speed conditions, it may interfere with vehicle maintenance work or cause the vehicle to behave in a way that is unintended by the driver.

[0005] The present invention has been made in consideration of the conventional situation, and an object of the present invention is to provide a steering control device, a steering control method, and a steer-by-wire system that can prevent control that matches the operation position of a steering operation input member with the steering angle of the wheels from adversely affecting vehicle maintenance and vehicle running. [Means for solving the problem]

[0006] In one aspect, the present invention provides a steer-by-wire system having a first actuator that applies torque to a steering operation input member and a second actuator that applies a steering force to wheels of a vehicle, wherein when the system is turned on, if the amount of deviation of the steering angle of the wheels from the operating position of the steering operation input member is equal to or greater than an allowable amount, a control signal is output to the first actuator to reduce the amount of deviation if the vehicle speed is equal to or less than a threshold, and a control signal is output to the second actuator to reduce the amount of deviation if the vehicle speed is greater than the threshold. [Effects of the Invention]

[0007] According to the present invention, it is possible to prevent the control for matching the operation position of the steering operation input member with the steering angle of the wheels from adversely affecting vehicle maintenance and vehicle running. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with a steer-by-wire system. [Figure 2] FIG. 10 is a diagram showing state transitions in alignment control. [Figure 3] 10A and 10B are diagrams illustrating transitions of the control state of a reaction motor and transitions of the control state of a steering motor. [Figure 4] 3 is a flowchart showing a control flow of the steer-by-wire system. [Figure 5] FIG. 10 is a diagram showing the state of alignment by the first alignment control. [Figure 6]FIG. 10 is a diagram showing the state of alignment by the first alignment control. [Figure 7] FIG. 10 is a diagram showing the state of alignment by the second alignment control. [Figure 8] FIG. 10 is a diagram showing the state of alignment by the second alignment control. [Figure 9] 10A and 10B are diagrams illustrating alignment by the second alignment control when the vehicle starts moving. [Figure 10] FIG. 10 is a diagram showing manual alignment. [Figure 11] 10 is a flowchart showing processing contents in a position adjustment mode. [Figure 12] FIG. 10 is a diagram showing the correlation between the speed limit and the vehicle speed in the second positioning control. [Figure 13] 10 is a flowchart showing the processing contents in a positioning mode in which a vehicle is judged to be in a stopped state or a moving state based on an accelerator operation amount. [Figure 14] FIG. 1 is a diagram showing a steer-by-wire system in which a steering operation input device includes a steering control device. [Figure 15] FIG. 1 illustrates a steer-by-wire system in which the steering device is equipped with a steering control device. DETAILED DESCRIPTION OF THE INVENTION

[0009] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 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 drawings. FIG. 1 is a schematic diagram showing an embodiment of a vehicle 100 equipped with a steer-by-wire system 200. As shown in FIG. The vehicle 100 is a four-wheeled automobile equipped with a pair of left and right front wheels 101, 102 and a pair of left and right rear wheels 103, 104.

[0010] The steer-by-wire system 200 includes a steering operation input device 300 to which the steering operation of the driver of the vehicle 100 is input via a steering wheel 310, a steering device 400 equipped with 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. In the steer-by-wire system 200, the steering operation input device 300 and the steering device 400 are mechanically separated. In other words, in the steer-by-wire system 200, the steering wheel 310 and the front wheels 101, 102 are mechanically separated.

[0011] The steering operation input device 300 includes a steering wheel 310 , a steering shaft 320 , a reaction force motor 330 , and an operation angle sensor 340 . The steering wheel 310 is a steering operation input member operated by the driver of the vehicle 100.

[0012] Reaction motor 330 is a reaction actuator (first actuator) provided to impart a steering reaction torque to steering wheel 310 in a pseudo manner. That is, the steering operation input device 300 is a device into which the driver's steering operation is input via the steering wheel 310, and has a reaction motor 330 that applies a steering reaction torque to the steering wheel 310.

[0013] The operation angle sensor 340 detects the rotation angle of the steering shaft 320 as an operation angle θ of the steering wheel 310 (in other words, the operation position). Specifically, the steering angle sensor 340 detects the neutral position of the steering wheel 310 as an steering angle θ=0 degrees. 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 when the steering wheel 310 is operated to the right from the neutral position, the operation angle sensor 340 detects the operation angle θ as a negative angle.

[0014] 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 using 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. The steering mechanism 420 is a mechanism that changes the steering angle δ of the front wheels 101, 102 by converting the rotational motion of the steering motor 410 into the linear motion of a rack bar using, for example, a rack and pinion system.

[0015] The steering angle sensor 430 is a sensor that detects the rotational position of the steering motor 410 or the position of the rack bar of the steering mechanism 420 to detect the steering angle δ of the front wheels 101 and 102 . Specifically, the steering angle sensor 430 detects the neutral position of the front wheels 101, 102 as a steering angle δ=0 degrees. The steering angle sensor 430 detects the steering angle δ as a positive angle when the front wheels 101, 102 are steered to the left from the neutral position, and detects the steering angle δ as a negative angle when the front wheels 101, 102 are steered to the right from the neutral position.

[0016] The neutral position of the front wheels 101, 102 is a position where the front wheels 101, 102 are not steered to either the left or right, and the vehicle 100 is traveling straight ahead. 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 and the front wheels 101, 102 are in a neutral position.

[0017] The steering control device 500 is an electronic control device that includes an MCU (Micro Controller Unit) 510 and controls the operation of the steer-by-wire system 200. The MCU 510 can also be referred to as a microcomputer, a processor, a processing unit, an arithmetic unit, or the like.

[0018] Then, the MCU 510 performs arithmetic processing on various signals acquired from the outside to determine a control signal for the reaction force motor 330 and a control signal for the steering motor 410, and outputs the determined control signals. 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, a function as a control unit that executes a steering control method.

[0019] Here, the steering control device 500 can include a pre-driver, an inverter, and the like for controlling the energization of the reaction force motor 330 and the energization of the steering motor 410. In addition to the steering control device 500, the system may be provided with a drive circuit including a pre-driver, an inverter, and the like.

[0020] The vehicle 100 is provided with an activation switch 650 that activates various systems of the vehicle 100, such as a power switch or an ignition switch, and the steering control device 500 acquires an on / off signal of the activation switch 650. The systems activated by activation switch 650 include steer-by-wire system 200. When activation switch 650 is turned on, steer-by-wire system 200 is powered on and activated, entering a system-on state. The vehicle 100 also includes wheel speed sensors 621-624 that detect wheel speeds WS1-WS4, which are the rotational speeds of the wheels 101-104, respectively.

[0021] The MCU 510 acquires signals indicating physical quantities related to the wheel speeds WS1-WS4 output by the wheel speed sensors 621-624 (or signals indicating physical quantities related to the vehicle speed VS calculated from the outputs of the wheel speed sensors 621-624), signals indicating physical quantities related to the steering angle θ output by the steering angle sensor 340, and signals indicating physical quantities related to the steering angle δ output by the steering angle sensor 430. Then, MCU 510 calculates a steering angle command value δtg, which is a target value of steering angle δ, based on information about the operation angle θ of steering wheel 310. Furthermore, MCU 510 determines a control signal based on the deviation between the steering angle δ detected by steering angle sensor 430 and steering angle command value δtg, and outputs the determined control signal to steering motor 410.

[0022] Furthermore, MCU 510 calculates a reaction torque command value TRtg, which is a target value of reaction torque TR, based on information such as vehicle speed VS determined from wheel speeds WS1-WS4 and operation angle θ of steering wheel 310. In addition, the MCU 510 can obtain the vehicle speed VS by acquiring the signals of the wheel speeds WS1-WS4 from the wheel speed sensors 621-624, and can also obtain information on the vehicle speed VS that other electronic control devices have calculated based on the signals of the wheel speeds WS1-WS4 via the in-vehicle network.

[0023] Then, the MCU 510 outputs a control signal based on the reaction torque command value TRtg to the reaction motor 330. In this way, MCU 510 controls the operation of steer-by-wire system 200 by controlling the steering force applied to front wheels 101, 102 and the reaction torque applied to steering wheel 310.

[0024] In steer-by-wire system 200, because steering wheel 310 and front wheels 101, 102 are mechanically separated, there may be a static misalignment between the operating position of steering wheel 310 and the steering angle δ of front wheels 101, 102. Therefore, when the system is turned on, if the deviation AD of the steering angle δ of the front wheels 101, 102 relative to the operating angle θ of the steering wheel 310 is equal to or greater than the allowable amount TD, the MCU 510 performs alignment control to actively change the operating angle θ or the steering angle δ using an actuator so as to reduce the deviation AD.

[0025] The deviation amount AD is an error between the actual steering angle δ and the steering angle command value δtg, which is uniquely determined based on the operation angle θ of the steering wheel 310. Furthermore, when actively changing the operation angle θ in the positioning control, the MCU 510 causes the reaction force motor 330 to generate a rotational driving force that rotates the steering wheel 310 to a position that corresponds to the steering angle δ.

[0026] By carrying out such alignment control, after alignment, the steering angle δ is controlled to correspond to the operation position of the steering wheel 310, improving the steering operability by the driver. Here, the MCU 510 determines whether to actively change the operation angle θ or the steering angle δ in the alignment control, depending on the physical quantity related to the vehicle speed VS. In other words, the MCU 510 switches between performing alignment control (hereinafter referred to as first alignment control) that actively changes the position of the steering wheel 310 using the reaction force motor 330, and performing alignment control (hereinafter referred to as second alignment control) that actively changes the steering angle δ of the front wheels 101, 102 using the steering motor 410, depending on a physical quantity related to the vehicle speed VS.

[0027] The reason why the MCU 510 switches between the first positioning control and the second positioning control depending on the condition of the vehicle speed VS will be explained below. Here, it is assumed that the second alignment control is performed to actively change the steering angle δ (in other words, the direction of the tires) while the vehicle 100 is stopped.

[0028] For example, when the vehicle 100 is parked in a maintenance workshop and maintenance work is being performed on the suspension or tires of the front wheels 101, 102, if a start switch 650 such as an ignition switch IGN-SW is turned on to turn the system on and start the second alignment control, the orientation of the tires may change unexpectedly, making it impossible to proceed with the maintenance work smoothly and safely. Furthermore, when the user of vehicle 100 parks vehicle 100 and the start switch 650 is turned on to start alignment control, the direction of the tires may change inadvertently, causing movable objects located near the front wheels 101, 102, which are the steered wheels, to interfere with the tires, resulting in unexpected movement of the movable objects or the movable objects becoming pinched between the tires and a fixed object such as a wall.

[0029] Concerns that arise when the second alignment control is performed while the vehicle 100 is stopped can be avoided by employing the first alignment control, which actively changes the position of the steering wheel 310. However, if the vehicle 100 starts with the steering wheel 310 being held by the driver before the alignment by the first alignment control is completed, the first alignment control attempts to align the operating position of the steering wheel 310 with the steering angle δ, which may cause the vehicle 100 to move forward with the operating position of the steering wheel 310 misaligned with the steering angle δ, resulting in vehicle behavior that is not intended by the driver.

[0030] Therefore, the steering control device 500 selectively uses the first alignment control and the second alignment control depending on the vehicle speed VS, thereby preventing the alignment control when the system is turned on from adversely affecting vehicle maintenance or vehicle driving. In other words, when the vehicle 100 is being serviced at a service workshop or when the vehicle 100 is parked, the vehicle 100 is in a stopped state.

[0031] If alignment is performed using the first alignment control while the vehicle is stopped, the direction of the tires will not be changed, which will prevent interference with maintenance work on the suspension, etc., and will also prevent movable objects near the vehicle 100 from being pushed or pinched by the tires while the vehicle is parked. On the other hand, if alignment is performed using the second alignment control while the vehicle 100 is running after starting, the steering angle δ is aligned with the operating angle θ (in other words, the direction of the tires is aligned with the operating position of the steering wheel 310), thereby preventing the vehicle 100 from traveling in a direction unintended by the driver.

[0032] Therefore, when the steering control device 500 performs the alignment control when the system is turned on, it compares the vehicle speed VS with a threshold value VSTH for determining whether to switch over to the alignment control. 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.

[0033] Here, the threshold value VSTH is set to 0 km / h or an extremely low vehicle speed. Therefore, when the vehicle speed VS is equal to or less than the threshold value VSTH, the vehicle 100 is in a stopped state, and when the vehicle speed VS is higher than the threshold value VSTH, the vehicle 100 is in a traveling state. In other words, when the steering control device 500 is turned on, it performs first alignment control when the vehicle 100 is stopped and the vehicle speed VS is below the threshold value VSTH, and it performs second alignment control when the vehicle 100 is moving and the vehicle speed VS is higher than the threshold value VSTH.

[0034] FIG. 2 is a diagram showing state transitions during alignment control by the steering control device 500. 3 shows the control states of the steering operation input device 300 and the steering device 400 in each state shown in FIG. The control states in Figure 2 include a first state which is a non-control state in the initial stage after startup, a second state in which first alignment control is implemented, a third state in which normal steering control is implemented, and a fourth state in which second alignment control is implemented.

[0035] When the activation switch 650 is turned on to turn on the steer-by-wire system 200, that is, in the initial state immediately after the steering control device 500 is activated, the steering control device 500 is in the first state. The first state is a state in which drive control of the reaction force motor 330 and the steering motor 410 is stopped, in other words, a state in which the reaction force motor 330 and the steering motor 410 are not controlled.

[0036] In the first state, the steering control device 500 determines the deviation AD [deg] of the steering angle δ of the front wheels 101, 102 from the steering angle command value δtg based on the operation angle θ of the steering wheel 310, and compares the determined deviation AD with the allowable amount TD. Then, the steering control device 500 transitions to the second state when the deviation amount AD is equal to or greater than the allowable amount TD and the vehicle 100 is in a stopped state where the vehicle speed VS is equal to or less than the threshold value VSTH. The deviation amount AD is the absolute value of the deviation angle.

[0037] The second state is a state in which the first alignment control is performed. Here, the steering control device 500 controls the rotational driving force that the reaction force motor 330 applies to the steering wheel 310 so that the operation angle θ of the steering wheel 310 changes to a position that corresponds to the steering angle δ of the front wheels 101, 102. Furthermore, the steering control device 500 keeps the steering motor 410 in a drive-stop state (in other words, in a non-controlled state) during the first alignment control.

[0038] In addition, 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 alignment control. In detail, the steering control device 500 limits the rotational torque applied by the reaction motor 330 to such an extent that the driver can operate the steering wheel 310 against the rotational torque applied by the reaction motor 330. In addition, the steering control device 500 limits the rotation speed of the steering wheel 310 to a level that prevents the driver's hands from interfering with the steering wheel 310 and causing a shock to the driver when the steering wheel 310 automatically rotates.

[0039] In addition, when the steering control device 500 is performing the first alignment control, it activates a warning device 640 provided in the vehicle 100 to notify the driver of the vehicle 100 that the alignment control is being performed (or that there is a minor abnormality in the steer-by-wire system 200). The warning device 640 is a warning lamp, a liquid crystal display device, a voice guidance device, or the like.

[0040] The warning issued by the warning device 640 allows the driver to recognize that alignment control is being performed, and prevents the driver from panicking even if the steering wheel 310 starts to rotate automatically. Furthermore, if the driver delays the start operation of the vehicle 100 due to the warning from the warning device 640, this will contribute to completing the alignment while the vehicle is stopped.

[0041] In this way, if the first alignment control is performed while the vehicle 100 is stopped, the operating angle θ of the steering wheel 310 is changed while the steering angle δ of the front wheels 101, 102 is maintained. Therefore, even if the alignment control is performed during suspension maintenance at a maintenance shop, the steering angle δ of the front wheels 101, 102 will not move inadvertently, and the maintenance work can be carried out smoothly and safely. Furthermore, even if alignment is performed while the user of the vehicle 100 is parking the vehicle 100, the steering angle δ of the front wheels 101, 102 does not move, so it is possible to avoid movable objects located near the front wheels 101, 102 interfering with the tires.

[0042] On the other hand, if the steering control device 500 determines in the first state that the deviation amount AD is less than the allowable amount TD, that is, if 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 that requires corrective action has occurred, it transitions to the third state regardless of the condition of the vehicle speed VS (in other words, whether the vehicle 100 is stopped or moving).

[0043] The third state is a normal steering state in which the reaction force motor 330 and the steering motor 410 are normally controlled. In other words, in the third state, the steering control device 500 controls the reaction force motor 330 so that it generates a pseudo steering reaction force, and also controls the steering motor 410 so 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.

[0044] Furthermore, when the steering control device 500 performs the first alignment control in the second state and the deviation amount AD becomes less than the allowable amount TD, that is, when alignment by the first alignment control is completed, the steering control device 500 transitions to the third state and performs normal control of the reaction force motor 330 and the steering motor 410. In this way, when the steering control device 500 performs the first alignment control while the vehicle 100 is stopped and the deviation amount AD falls below the allowable amount TD, the steering control device 500 applies a steering reaction torque to the steering wheel 310 using the reaction motor 330, and transitions to a normal steering control state in which a steering force based on the operating angle θ, which is operation information of the steering wheel 310, is applied to the front wheels 101, 102 using the steering motor 410.

[0045] In addition, when the steering control device 500 is in the second state and performing the first alignment control, if it detects the vehicle 100 starting to move before the alignment by the first alignment control is completed, that is, before the deviation amount AD becomes less than the allowable amount TD, it transitions to the fourth state. Note that detection of the vehicle 100 starting to move means detection of a vehicle speed VS higher than the threshold value VSTH, in other words, detection of the transition of the vehicle 100 from a stopped state to a moving state, or detection of input of a vehicle speed signal.

[0046] The fourth state is a state in which the second alignment control is performed. 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. Furthermore, the steering control device 500 causes the reaction motor 330 to generate a pseudo steering reaction force during the second alignment control in the fourth state.

[0047] 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. Therefore, when the vehicle 100 starts moving with the driver keeping the steering wheel 310 steered, the steering angle δ of the front wheels 101, 102 is changed to match the position of the steering wheel 310, thereby preventing the vehicle from behaving in a way that is not intended by the driver.

[0048] Furthermore, in the second positioning control, the steering control device 500 applies a reaction torque to the steering wheel 310 using the reaction motor 330, thereby preventing the position of the steering wheel 310 from moving unnecessarily, thereby stabilizing the maneuverability when the vehicle 100 starts moving. Here, the steering control device 500 activates the warning device 640 when the second alignment control is being performed, in the same way as when the first alignment control is being performed.

[0049] Then, when the second alignment control is performed in the fourth state and the deviation amount AD becomes less than the allowable amount TD, that is, when alignment by the second alignment control is completed, the steering control device 500 transitions to the third state and performs normal control of the reaction force motor 330 and the steering motor 410. In other words, when the steering control device 500 performs the second alignment control while the vehicle 100 is running and the deviation amount AD falls below the allowable amount TD, the steering control device 500 applies a reaction torque to the steering wheel 310 using the reaction motor 330, and transitions to a normal steering control state in which a steering force based on the operating angle θ of the steering wheel 310 is applied to the front wheels 101, 102 using the steering motor 410.

[0050] Furthermore, when the steering control device 500 determines in the first state (more specifically, the non-control state at the beginning after startup) that the deviation amount AD is equal to or greater than the allowable amount TD and that the vehicle speed VS is greater than the threshold value VSTH and the vehicle 100 is in a traveling state, it transitions to the fourth state and performs the second alignment control. That is, when the vehicle 100 is moving at an early stage after startup, the steering control device 500 immediately performs the second alignment control without performing the first alignment control.

[0051] FIG. 4 is a flowchart showing the flow of control of the steer-by-wire system 200 by the steering control device 500, including the alignment control described with reference to FIGS. The flowchart in FIG. 4 is divided into control processing for the steering operation input device 300 and control processing for the steering device 400, and each control processing includes an initial processing, a positioning mode, a normal running mode, and an end mode.

[0052] When a start switch 650 such as an ignition switch IGN-SW is turned on to turn on the system, the steering control device 500 executes initial processing for each of the steering operation input device 300 and the steering device 400. Thereafter, the steering control device 500 shifts to the alignment mode, and transitions to any one of the above-mentioned first state, second state, third state, and fourth state according to the conditions of the deviation amount AD and the vehicle speed VS.

[0053] As mentioned above, the first state is an initial non-control state after startup, the second state is a state in which the first alignment control is performed, the third state is a state in which normal steering control is performed upon completion of alignment, and the fourth state is a state in which the second alignment control is performed. The steering operation input device 300 is in a non-control state in the first state, but in the second state is in a position control state in which the reaction force motor 330 is controlled so that the operation angle θ corresponds to the steering angle δ. Furthermore, in the third and fourth states, 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.

[0054] On the other hand, the steering device 400 is in a non-controlled state in the first and second states, but in the third and fourth states, it is in a position-controlled state in which the steering motor 410 is controlled so that the steering angle δ corresponds to the operating angle θ. Furthermore, in the alignment mode, the steering control device 500 activates the warning device 640, for example, turns on the warning lamp, in states other than the third state.

[0055] Although the steering control device 500 does not perform alignment control in the first state, since this is a branching point as to whether or not alignment is to be performed, the warning device 640 is activated in the first state, and continues to be activated when the state transitions from the first state to the second state or the fourth state. Then, when the steering control device 500 completes alignment in the second or fourth state and transitions to the third state, or when it transitions from the first state to the third state, it transitions to normal driving mode and stops the operation of the warning device 640. Thereafter, when the start switch 650 such as the ignition switch IGN-SW is turned off, the steering control device 500 transitions to a termination mode, performs a predetermined termination process, and then shuts off.

[0056] 5 and 6 show examples of how the steering angle δ and the operation angle θ change during the first alignment control. FIG. 5 shows how the steering angle δ of the front wheels 101, 102 is shifted to the left from the straight ahead position (in other words, the neutral position), while the steering angle θ of the steering wheel 310 is near the neutral position, and how the first positioning control is used to align the steering angle θ to the steering angle δ.

[0057] In this case, when the ignition switch IGN-SW serving as the start switch 650 is turned on to turn the system on, the steering control device 500 rotates the steering wheel 310 counterclockwise using the reaction force motor 330, and moves the operating angle θ of the steering wheel 310 to a position rotated to the left of the neutral position, which is a position corresponding to the steering angle δ. While the steering wheel 310 is being rotated by the rotational driving force of the reaction force motor 330, the steering control device 500 keeps the steering motor 410 in a non-controlled state and keeps the steering angle δ at the initial angle. In addition, while the steering control device 500 is performing alignment using the first alignment control, in other words, while it is actively changing the operating angle θ of the steering wheel 310, it activates a warning device 640 such as a warning lamp to warn the driver of the vehicle 100 that alignment is in progress.

[0058] FIG. 6 shows how the first positioning control is used to align the operating angle θ to the steering angle δ when the steering angle δ of the front wheels 101, 102 is near the straight-ahead position, while the operating angle θ of the steering wheel 310 is shifted to the left from the neutral position. In this case, when the ignition switch IGN-SW serving as the start switch 650 is turned on to turn the system on, the steering control device 500 rotates the steering wheel 310 clockwise using the reaction force motor 330, and moves the operating angle θ of the steering wheel 310 to the neutral position, which is a position corresponding to the steering angle δ.

[0059] Again, during alignment, the steering control device 500 keeps the steering motor 410 in an uncontrolled state to keep the steering angle δ at the original angle, that is, the neutral position, and also activates the warning device 640. Since the first alignment control is performed when the vehicle 100 is stopped, the orientation of the front wheels 101, 102 does not change inadvertently when the vehicle 100 is stopped, and even if the system is turned on during maintenance work or when there is a movable object near the front wheels 101, 102, adverse effects on the maintenance work or the movable object are prevented.

[0060] On the other hand, FIGS. 7 and 8 show examples of how the steering angle δ and the operation angle θ change during the second alignment control. FIG. 7 shows how the steering angle δ of the front wheels 101, 102 is shifted to the left from the straight ahead position (in other words, the neutral position), while the operating angle θ of the steering wheel 310 is near the neutral position, and how the steering angle δ is adjusted to the operating angle θ by the second positioning control. 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 to the neutral position.

[0061] FIG. 8 also shows how the second positioning control is used to align the steering angle θ to the steering angle δ when the steering angle δ of the front wheels 101, 102 is near the straight-ahead position, while the steering angle θ of the steering wheel 310 is shifted to the left from the neutral position. 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 shifted to the left that corresponds to the operating angle θ of the steering wheel 310.

[0062] As shown in Figures 7 and 8, the second alignment control actively changes the steering angle δ of the front wheels 101, 102, and therefore, if performed while the vehicle is stopped, it may have an adverse effect on maintenance work on the front wheels 101, 102 or on movable objects located near the front wheels 101, 102. However, the steering control device 500 performs the first alignment control when the vehicle 100 is stopped, and switches to the second alignment control when the vehicle is moving, thereby preventing the alignment control when the vehicle is stopped from adversely affecting maintenance work or movable objects located near the front wheels 101, 102. Furthermore, the steering control device 500 performs second alignment control while the vehicle 100 is running, and quickly corrects the steering angle δ to match the operating angle θ of the steering wheel 310, thereby preventing vehicle behavior that is not intended by the driver.

[0063] FIG. 9 shows how the steering angle δ is changed by the second alignment control when the vehicle 100 starts from a state in which there is a deviation AD between the operating angle θ and the steering angle δ and the steering wheel 310 is held steered by the driver. Here, the steering wheel 310 is in a substantially neutral position, whereas the front wheels 101 and 102 are steered to the left of their straight ahead positions.

[0064] Therefore, the steering control device 500 transitions to the second alignment control, i.e., the fourth state, upon the start of the vehicle 100, i.e., the transition from a stopped state to a running state, and controls the steering force of the steering motor 410 so as to quickly change the steering angle δ of the front wheels 101, 102 to a straight-ahead position. This prevents the vehicle 100 from turning left against the driver's intention to keep the steering wheel 310 in the neutral position and drive the vehicle 100 straight.

[0065] Meanwhile, in the first alignment control, as described above, the steering control device 500 limits the rotational torque applied by the reaction motor 330 to such an extent that the driver can operate the steering wheel 310 against the rotational torque applied by the reaction motor 330. Therefore, in the first alignment control, the driver is allowed to intervene in changing the operation angle θ, and the driver can manually perform alignment.

[0066] FIG. 10 shows manual alignment in the second state in which the first alignment control is performed. FIG. 10 shows manual alignment from a state in which the steering wheel 310 is near the neutral position, while the steering angle δ of the front wheels 101, 102 is pointing to the left of the neutral position.

[0067] When the vehicle 100 is stopped, the first alignment control is performed and the reaction motor 330 applies a rotational driving force to the steering wheel 310. At this time, the driver can manually align the steering wheel 310 by turning the steering wheel 310 to the left. Here, when the alignment is complete, the operation of the warning device 640 is stopped (for example, the warning lamp is turned off), so that the driver can recognize that the alignment is complete, and can stop rotating the steering wheel 310 when the operating angle θ corresponding to the steering angle δ is reached.

[0068] Furthermore, when alignment is completed and the system transitions from state 2, in which the first alignment control is implemented, to state 3, in which normal control is restored, the reaction force motor 330 generates a reaction force to the driver's operation of the steering wheel 310, thereby limiting excessive steering operation by the driver. Furthermore, if the vehicle 100 starts moving during manual alignment, the system transitions to the fourth state, i.e., the second alignment control, and the steering motor 410 generates a steering force to align the steering angle δ of the front wheels 101, 102 with the operating angle θ of the steering wheel 310.

[0069] As described above, the steering control device 500 can transition from the second state (first alignment control) to the fourth state (second alignment control) based on the vehicle speed VS, and can also transition from the second state (first alignment control) to the fourth state (second alignment control) based on a change in the shift position (in other words, the driving mode) of the automatic transmission that constitutes the power transmission system of the vehicle 100. When the driver starts the vehicle 100 from a stopped state (specifically, moving forward or backward), the driver performs a shift operation to change the shift position of the automatic transmission from parking P or neutral N to a driving range such as drive D or reverse R.

[0070] Therefore, when a shift operation is performed to change from parking P or neutral N to drive D or reverse R, etc., the steering control device 500 regards such shift operation as preparation for departure, and transitions from the second state (first alignment control) to the fourth state (second alignment control) without waiting for actual departure. As a result, when the vehicle 100 starts moving during the first alignment control, the start timing of the second alignment control, which aligns the steering angle δ with the operating angle θ, is advanced, thereby hastening the correction of the deviation and more stably preventing the occurrence of vehicle behavior unintended by the driver.

[0071] Furthermore, the steering control device 500 can include the duration of the first alignment control as a condition for transitioning from the second state (first alignment control) to the fourth state (second alignment control). For example, the maximum time required for alignment using the first alignment control can be estimated from the expected maximum amount of deviation, and if the first alignment control continues beyond this maximum time, it can be estimated that some kind of abnormality is preventing alignment that actively moves the operating position of the steering wheel 310.

[0072] Therefore, when the duration of the first alignment control exceeds the set time, the steering control device 500 determines that alignment by the first alignment control is impossible, and transitions to the fourth state (second alignment control). This prevents the reaction force motor 330 and its drive circuit from overheating due to the reaction force motor 330 continuing to generate a rotational drive force even though alignment by the first alignment control is not possible. Furthermore, even if alignment by the first alignment control is not possible, the deviation amount AD can be reduced by the time the vehicle 100 starts moving, thereby preventing the vehicle from behaving in a manner unintended by the driver.

[0073] The flowchart in Figure 11 shows the processing flow in the alignment mode when switching the shift position of the automatic transmission 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). When the steering control device 500 is started by turning on the system based on the start switch 650 being turned on, first, in step S701, it is determined whether or not the deviation amount AD is equal to or greater than the allowable amount TD.

[0074] Here, if the deviation amount AD is less than the allowable amount TD and is not so large that alignment processing is required, the steering control device 500 proceeds to step S702. The steering control device 500 performs normal control of the reaction force motor 330 and the steering motor 410 in step S702. 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.

[0075] On the other hand, if the deviation amount AD is equal to or greater than the allowable amount TD and the execution of alignment control is requested, the steering control device 500 proceeds to step S703. In step S703, the steering control device 500 compares the vehicle speed VS with the threshold value VSTH to determine whether the vehicle 100 is in a stopped state or a moving state.

[0076] 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 a stopped state, the process proceeds to step S704. The steering control device 500 performs the first alignment control in step S704. In other words, the steering control device 500 transitions from the first state (non-control state) to the second state (first alignment control) in step S704.

[0077] The steering control device 500 that has transitioned to the second state (first alignment control) determines in the next step S705 whether or not the deviation amount AD has become less than the allowable amount TD, that is, whether or not the alignment has been completed. Then, when the deviation amount AD is less than the allowable amount TD as a result of the first alignment control, the steering control device 500 proceeds to step S702. 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 transitions from the second state (first alignment control) to the third state (normal steering control).

[0078] On the other hand, if the state in which the deviation amount AD is equal to or greater than the allowable amount TD is maintained, the steering control device 500 proceeds to step S706. In step S706, the steering control device 500 determines whether the vehicle speed VS is equal to or less than the threshold value VSTH, thereby determining whether the vehicle 100 has transitioned from a stopped state to a traveling state.

[0079] Here, when it is determined that the vehicle speed VS is higher than the threshold value VSTH and the vehicle 100 has transitioned from a stopped state to a traveling state, the steering control device 500 proceeds to step S709 and performs the second positioning control. In other words, when the steering control device 500 detects that the vehicle 100 has started moving in the second state in which the first alignment control is being performed, it transitions from the second state (first alignment control) to the fourth state (second alignment control).

[0080] Furthermore, if the vehicle speed VS is equal to or less than the threshold value VSTH and it is determined that the vehicle 100 is maintaining a stopped state, the steering control device 500 proceeds to step S707. In step S707, the steering control device 500 acquires a signal from the shift position sensor 630, which detects the shift position (driving mode) of the automatic transmission of the vehicle 100, and determines whether the shift position has been changed from Parking P or Neutral N to Drive D or Reverse R.

[0081] Then, when the steering control device 500 detects a change from Parking P or Neutral N to Drive D or Reverse R, the process proceeds to step S709, where the second alignment control is performed. In other words, when the steering control device 500 detects a change from parking P or neutral N to drive D or reverse R, it transitions from the second state (first alignment control) to the fourth state (second alignment control).

[0082] That is, when a change from Parking P or Neutral N to Drive D or Reverse R is made, there is a high possibility that the driver will start the vehicle 100 afterwards. Therefore, when a change is made from parking P or neutral N to drive D or reverse R, the steering control device 500 estimates the subsequent departure of the vehicle 100, and switches from the first alignment control to the second alignment control without waiting for the actual departure of the vehicle 100.

[0083] On the other hand, if the steering control device 500 does not detect a change from Parking P or Neutral N to Drive D or Reverse R, the process proceeds to step S708. In step S708, the steering control device 500 determines whether or not the duration T1, which is the time during which the first alignment control is continuously performed, is equal to or longer than a predetermined time TTH.

[0084] Then, if the duration T1 is equal to or longer than the predetermined time TTH, that is, if the alignment by the first alignment control has not been completed even after the time when the alignment is expected to be completed has elapsed, the steering control device 500 proceeds to step S709 and performs the second alignment control. As a result, if alignment is not completed even after continuing the first alignment control for a predetermined time TTH, the steering control device 500 will transition from the second state (first alignment control) to the fourth state (second alignment control) even if the stopped state is maintained.

[0085] On the other hand, if the duration T1 is less than the predetermined time TTH, the steering control device 500 returns to step S704 and continues the first positioning control (second state). Moreover, while the second alignment control is being performed, the steering control device 500 determines in step S710 whether or not the deviation amount AD has become less than the allowable amount TD.

[0086] Then, when the deviation amount AD becomes less than the allowable amount TD as a result of the second alignment control, the steering control device 500 proceeds to step S702 and performs normal control of the reaction force motor 330 and the steering motor 410. In other words, when the deviation amount AD becomes less than the allowable amount TD due to the second alignment control, the steering control device 500 transitions from the fourth state (second alignment control) to the third state (normal steering control). On the other hand, if the deviation amount AD remains equal to or greater than the allowable amount TD, the steering control device 500 returns to step S709 and continues the second alignment control.

[0087] Incidentally, in the second alignment control, the steering control device 500 can reduce the driver's discomfort in operation after starting by increasing the rotational speed (operating speed) of the steering motor 410 as the vehicle speed VS increases (in other words, as the physical quantity related to the vehicle speed increases). 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, so that the higher the vehicle speed VS, the faster the rotational speed of the steering motor 410, i.e., the steering speed, and the higher the vehicle speed VS, the more quickly the alignment can be completed.

[0088] FIG. 12 is a diagram showing one aspect of the correlation between the speed limit of the steering motor 410 and the vehicle speed VS in the second positioning control. In the example of the characteristics in FIG. 12, when the vehicle speed VS is in the speed range from 0 km / h to 1 km / h, the speed limit VSL is maintained at the first speed limit VSL1.

[0089] In addition, when the vehicle speed VS is in the range of 1 km / h to 3 km / h, the speed limit VSL gradually increases from a first speed limit VSL1 to a second speed limit VSL2 (VSL2>VSL1) as the vehicle speed VS increases. When the vehicle speed VS is in a speed range of 3 km / h or higher, the speed limit VSL is maintained at the second speed limit VSL2.

[0090] In the second positioning control, the steering control device 500 sets a speed limit VSL according to the detected value of the vehicle speed VS with the characteristics shown in Figure 12, and controls the drive of the steering motor 410 so that the rotational speed of the steering motor 410 does not exceed the speed limit VSL. Here, the steering control device 500 increases the speed limit VSL as the vehicle speed VS increases, thereby preventing squealing caused by a sudden change in the direction of the front wheels 101, 102 at extremely low speeds immediately after starting, and also prevents vehicle behavior that is not intended by the driver from occurring by speeding up the correction of the deviation amount AD when the vehicle speed VS increases.

[0091] Furthermore, the steering control device 500 can switch between the first positioning control and the second positioning control based on the accelerator operation amount, which is a physical quantity correlated with the vehicle speed VS, instead of the vehicle speed VS. 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 moving state.

[0092] 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 it via an in-vehicle network. Then, the steering control device 500 compares the acquired accelerator operation amount AC with the threshold ACTH. Here, the threshold ACTH is adapted to a value that the accelerator operation amount AC does not exceed when the vehicle 100 is stopped, but exceeds when the vehicle 100 is moving.

[0093] Then, when the physical quantity related to the accelerator operation amount AC is equal to or less than the threshold ACTH and it can be estimated that the vehicle 100 is in a stopped state, the steering control device 500 performs the first alignment control. Furthermore, when the physical quantity related to the accelerator operation amount AC is greater than the threshold ACTH and it can be estimated that the vehicle 100 is in a traveling state, the steering control device 500 performs the second positioning control.

[0094] The flowchart in FIG. 13 shows the flow of processing in the alignment mode, which applies processing for distinguishing between a stopped state and a traveling state based on the accelerator operation amount AC. The flowchart in FIG. 13 differs from the flowchart in FIG. 11 only in the processing content in steps S703A and S706A, and the same processing as in the flowchart in FIG. 11 is performed in each of the other steps. Therefore, the processing contents in steps S703A and S706A will be explained, and explanations of the processing contents in the other steps will be omitted.

[0095] In step S703A, the steering control device 500 determines whether the accelerator operation amount AC is equal to or less than a threshold ACTH. Then, in step S703A, if the steering control device 500 determines that the accelerator operation amount AC is less than or equal to the threshold ACTH and the vehicle 100 is stopped, the process proceeds to step S704, and if the steering control device 500 determines that the accelerator operation amount AC is greater than the threshold ACTH and the vehicle 100 is moving, the process proceeds to step S709.

[0096] Similarly, in step S706A, the steering control device 500 determines whether the accelerator operation amount AC is equal to or less than a threshold ACTH. If the steering control device 500 determines in step S706A that the accelerator operation amount AC is equal to or less than the threshold ACTH, the process proceeds to step S707, and if it determines that the accelerator operation amount AC is greater than the threshold ACTH, the process proceeds to step S709. If the steering control device 500 distinguishes between a stopped state and a moving state based on the accelerator operation amount AC instead of the vehicle speed VS, the response of switching from the first positioning control to the second positioning control when the vehicle 100 starts moving can be improved, and the occurrence of vehicle behavior unintended by the driver can be more stably suppressed.

[0097] The steer-by-wire system 200 shown in FIG. 1 is provided with the steering operation input device 300, the steering device 400, and the steering control device 500 separately, but the steering operation input device 300 or the steering device 400 may be provided integrally with the steering control device 500. In addition, when the steering operation input device 300 or the steering device 400 is integrally equipped with the steering control device 500, it means that the steering operation input device and the steering control device 500, or the steering device 400 and the steering control device 500, form a single unit.

[0098] FIG. 14 shows a steer-by-wire system 200 in which a steering operation input device 300 includes a steering control device 500. The steer-by-wire system 200 shown in FIG. 14 differs from the steer-by-wire system 200 shown in FIG. 1 in that the steering operation input device 300 is equipped with a steering control device 500. However, since the other configurations are the same as those in FIG. 1, detailed explanations of the respective elements will be omitted.

[0099] The steer-by-wire system 200 in FIG. 14 is configured by assembling a steering operation input device 300 equipped with a steering control device 500 and a steering device 400 to a vehicle 100. Then, the steering control device 500 provided in the steering operation input device 300 outputs a control signal for the reaction force motor 330 and a control signal for the steering motor 410 in accordance with the transition between the 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) described above.

[0100] FIG. 15 also shows a steer-by-wire system 200 in which the steering device 400 is equipped with a steering control device 500 . The steer-by-wire system 200 shown in FIG. 15 differs from the steer-by-wire system 200 shown in FIG. 1 in that the steering device 400 is equipped with a steering control device 500. However, since the other configurations are the same as those in FIG. 1, detailed explanations of the individual elements will be omitted.

[0101] The steer-by-wire system 200 in FIG. 15 is configured by assembling a steering device 400 equipped with a steering control device 500 and a steering operation input device 300 to a vehicle 100. Then, the steering control device 500 provided in the steering device 400 outputs a control signal for the reaction force motor 330 and a control signal for the steering motor 410 in accordance with the transition between the 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) described above.

[0102] The technical ideas explained in the above embodiments can be used in appropriate combinations as long as no contradiction occurs. Furthermore, although the contents of the present invention have been specifically described with reference to preferred embodiments, it is obvious that a person skilled in the art can adopt various modified embodiments based on the basic technical idea and teachings of the present invention.

[0103] The trigger for turning on the steer-by-wire system 200 is not limited to turning on the activation switch, but may be, for example, detection of entry into a vehicle, unlocking of doors, or the like. Steer-by-wire system 200 may also include a backup mechanism that can mechanically couple steering wheel 310 and front wheels 101, 102 with a clutch or the like.

[0104] In addition, the steering control device 500 performs both a process of determining whether the vehicle is stopped or running based on the vehicle speed VS, and a process of determining whether the vehicle is stopped or running based on the accelerator operation amount AC, and can transition from the second state (first alignment control) to the fourth state (second alignment control) when a transition to the running state is detected in either of the determination processes. In this case, even if the accelerator operation amount AC is below the threshold ACTH, when the steering control device 500 detects the driving state based on the vehicle speed VS, it transitions from the second state (first alignment control) to the fourth state (second alignment control).

[0105] Conversely, even if the vehicle speed VS is below the threshold value VSTH, when the steering control device 500 detects the driving state based on the accelerator operation amount AC, it transitions from the second state (first alignment control) to the fourth state (second alignment control). According to this configuration, for example, when the vehicle 100 starts moving from a stopped state on a downhill slope by releasing the brakes, the control is transitioned to the second positioning control based on an increase in the vehicle speed VS, thereby preventing the occurrence of vehicle behavior unintended by the driver. Furthermore, when starting by normal accelerator operation, the accelerator operation amount AC increases before the vehicle speed VS increases, so that transition to the fourth state (second alignment control) can be performed responsively when the vehicle 100 starts moving.

[0106] Moreover, the steering control device 500 can transition from the second state (first alignment control) to the fourth state (second alignment control) based on the release of the parking brake. This is because when the parking brake is released, it can be estimated that the vehicle 100 will subsequently start moving, just as if the shift position had been changed from Parking P or Neutral N to Drive D or Reverse R.

[0107] Furthermore, the steering control device 500 can transition from the second state (first alignment control) to the fourth state (second alignment control) when the parking brake is released and the vehicle is shifted into drive D or reverse R. According to this configuration, the accuracy of estimating the start of the vehicle 100 increases, and the transition from the second state (first alignment control) to the fourth state (second alignment control) can be more appropriately performed. [Explanation of symbols]

[0108] 100...vehicle, 101, 102...front wheels, 200...steer-by-wire system, 300...steering operation input device, 310...steering wheel (steering operation input member), 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 operation input device having a first actuator to which a driver's steering operation is input via a steering operation input member and which applies torque to the steering operation input member; a steering device having a second actuator that applies a steering force to wheels of the vehicle; The vehicle is provided with a steer-by-wire system having A steering control device including a control unit that outputs control signals to the first actuator and the second actuator, The control unit When the system is turned on, a physical quantity related to a vehicle speed, a physical quantity related to an operation position of the steering operation input member, and a physical quantity related to a steering angle of the wheels; When the deviation amount of the steering angle from the operation position is equal to or greater than a tolerance, When the physical quantity related to the vehicle speed is equal to or smaller 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 greater than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount. Steering control device.

2. The steering control device according to claim 1, The control unit Acquire an on / off signal of a start switch of the vehicle; The time when the start switch of the vehicle is turned on is defined as the time when the system is turned on. Steering control device.

3. The steering control device according to claim 1, The control unit determining whether the vehicle is in a stopped state or a moving state by comparing the physical quantity related to the vehicle speed with the threshold value; When the vehicle is stopped, a control signal is output to the first actuator so as to reduce the amount of deviation; When the vehicle is in a traveling state, a control signal is output to the second actuator so as to reduce the amount of deviation. Steering control device.

4. The steering control device according to claim 3, The control unit When the deviation amount falls below the allowable amount while the vehicle is stopped, the first actuator applies a reaction torque to the steering operation input member, and the second actuator applies a steering force based on operation information input to the steering operation input device to the wheels. Steering control device.

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

6. The steering control device according to claim 5, The control unit When the deviation amount falls below the allowable amount during the running state of the vehicle, the first actuator applies a reaction torque to the steering operation input member, and the second actuator applies a steering force based on operation information input to the steering operation input device to the wheels. Steering control device.

7. The steering control device according to claim 3, The control unit when a control signal is output to the first actuator so as to reduce the amount of deviation while the vehicle is stopped, a driver is allowed to intervene in changing the operation position; When the deviation amount falls below the allowable amount, a reaction torque is applied to the steering operation input member by the first actuator. Steering control device.

8. The steering control device according to claim 3, The control unit When a control signal is output to the first actuator so as to reduce the deviation amount while the vehicle is stopped, if a driving mode of an automatic transmission of the vehicle is changed from parking or neutral to drive or reverse, switching to a state in which a control signal is output to the second actuator so as to reduce the amount of deviation; Steering control device.

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

10. The steering control device according to claim 1, The control unit activating a warning device provided in the vehicle when a control signal is output to the first actuator or the second actuator so as to reduce the amount of deviation; Steering control device.

11. The steering control device according to claim 1, The control unit a physical quantity related to an accelerator operation amount of the vehicle is acquired as the physical quantity related to the vehicle speed; When the physical quantity related to the accelerator operation amount is equal to or smaller 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 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. Steering control device.

12. The steering control device according to claim 1, The control unit If the deviation amount does not fall below the allowable amount even after the first actuator has been continuously operated for a set time, output of the control signal to the first actuator is stopped. Steering control device.

13. The steering control device according to claim 12, The control unit After stopping the output of the control signal to the first actuator, outputting a control signal to the second actuator so as to reduce the amount of deviation. Steering control device.

14. The steering control device according to claim 13, The control unit applying a reaction torque to the steering operation input member by the first actuator when outputting a control signal to the second actuator after stopping output of the control signal to the first actuator; Steering control device.

15. a steering operation input device having a first actuator to which a driver's steering operation is input via a steering operation input member and which applies torque to the steering operation input member; a steering device having a second actuator that applies a steering force to wheels of the vehicle; A steering control method executed by a control unit provided in the vehicle equipped with a steer-by-wire system having the following: When the system is turned on, a physical quantity related to a vehicle speed, a physical quantity related to an operation position of the steering operation input member, and a physical quantity related to a steering angle of the wheels; When the deviation amount of the steering angle from the operation position is equal to or greater than a tolerance, When the physical quantity related to the vehicle speed is equal to or smaller 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 greater than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount. Steering control method.

16. A steer-by-wire system mounted on a vehicle, comprising: a steering operation input device having a first actuator to which a driver's steering operation is input via a steering operation input member and which applies torque to the steering operation input member; a steering device having a second actuator that applies a steering force to wheels of the vehicle; a control unit that outputs control signals to the first actuator and the second actuator, The control unit When the system is turned on, a physical quantity related to a vehicle speed, a physical quantity related to an operation position of the steering operation input member, and a physical quantity related to a steering angle of the wheels; When the deviation amount of the steering angle from the operation position is equal to or greater than a tolerance, When the physical quantity related to the vehicle speed is equal to or smaller 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 greater than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount. Steer-by-wire system.

17. a steering operation input device having a first actuator to which a driver's steering operation is input via a steering operation input member and which applies torque to the steering operation input member; a steering device having a second actuator that applies a steering force to wheels of the vehicle; A steering control device provided in the steering device of a steer-by-wire system having the steering control device has a control unit that outputs control signals to the first actuator and the second actuator, The control unit When the system is turned on, a physical quantity related to a vehicle speed, a physical quantity related to an operation position of the steering operation input member, and a physical quantity related to a steering angle of the wheels; When the deviation amount of the steering angle from the operation position is equal to or greater than a tolerance, When the physical quantity related to the vehicle speed is equal to or smaller 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 greater than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount. Steering control device.

18. a steering operation input device having a first actuator to which a driver's steering operation is input via a steering operation input member and which applies torque to the steering operation input member; a steering device having a second actuator that applies a steering force to wheels of the vehicle; A steering control device provided in the steering operation input device of a steer-by-wire system having the steering control device has a control unit that outputs control signals to the first actuator and the second actuator, The control unit When the system is turned on, a physical quantity related to a vehicle speed, a physical quantity related to an operation position of the steering operation input member, and a physical quantity related to a steering angle of the wheels; When the deviation amount of the steering angle from the operation position is equal to or greater than a tolerance, When the physical quantity related to the vehicle speed is equal to or smaller 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 greater than the threshold value, a control signal is output to the second actuator so as to reduce the deviation amount. Steering control device.

Images