Steering control device and steering control method

Abstract

A steering control device (1) comprises: a target steering correspondence value computation unit (2) that computes a target steering correspondence value (θp*) such that a ratio (α) of the change in a steering angle (θi) with respect to the change in the control input of an operating member (11) is greater than 1; a control signal generation unit (64) that generates a control signal for activating a steering unit (5); and a mode switching unit (63) that switches control modes for activating the steering unit (5). The mode switching unit (63) executes an operation determination process for determining whether an operating condition for detecting a valid operation of the operating member (11) by a driver is met while an automated driving control mode is active and a mode switching process that switches to a manual driving control mode if the operating condition is met. The operation determination process includes a process for determining as invalid an operation not intended by the driver.

Description

[Technical Field]

[0001] The present disclosure relates to a steering control device and a steering control method. [Background technology]

[0002] Conventionally, there is a steer-by-wire steering device in which the power transmission path between an operation unit to which a steering wheel is connected and a steering unit that steers the steered wheels is separated. For example, as described in Patent Document 1, a steering control device that controls such a steering device changes the angle ratio of the steering angle of the steered wheels to the steering angle of the steering wheel depending on the driving conditions of the vehicle.

[0003] Patent Document 2 discloses a vehicle that employs a joystick in addition to or instead of a steering wheel as an operating member operated by the driver. When a joystick is used as the operating member, it is possible to reduce the amount of operation required to steer the steered wheels compared to when a steering wheel is used as the operating member, thereby improving convenience for the driver. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-30837 [Patent Document 2] Japanese Patent Application Publication No. 8-34353 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, when a joystick is used as an operating member, reducing the amount of operation required to steer the steered wheels increases the amount of change in the steering angle relative to the amount of change in the operation. In other words, even a small amount of joystick operation results in a large change in the steering angle of the steered wheels. Therefore, even if the amount of joystick operation is small, the operation must be validated. In this case, for example, if the driver touches the joystick unintentionally, there is a possibility that the driver's unintended operation will be validated. This problem is not limited to cases where a joystick is used as an operating member, but can similarly occur in any steering device in which the amount of change in the steering angle relative to the amount of change in the operation member increases. [Means for solving the problem]

[0006] One aspect of the present disclosure provides a steering control device for controlling a steering device of a vehicle. The steering device has a structure in which a power transmission path is separated between an operation unit having an operation member and a steering unit configured to steer steered wheels. The steering control device includes: a target steering corresponding value calculation unit configured to calculate a target steering corresponding value, which is a target value of a convertible value that can be converted into a steering angle of the steered wheels based on operation of the operation member, and to calculate the target steering corresponding value so that the ratio of a change in the steering angle to a change in operation amount of the operation member is greater than 1; a control signal generation unit configured to generate a control signal for operating the steering unit based on the target steering corresponding value; and a mode switching unit that switches a control mode for operating the steering unit between an automatic driving control mode and a manual driving control mode. The vehicle includes an external control device that outputs automatic driving instructions to realize automatic driving that automatically changes the direction of travel of the vehicle. The automatic driving control mode is a mode in which the automatic driving instructions are reflected in control for operating the steering unit. The manual driving control mode is a mode in which the automatic driving instruction is not reflected in the control for operating the steering unit. The mode switching unit is configured to execute an operation determination process to determine whether an operation condition for detecting a valid operation by the driver of the operating member is satisfied during the automatic driving control mode, and a mode switching process to switch from the automatic driving control mode to the manual driving control mode when the operation condition is satisfied. The operation determination process includes a process to determine that an operation unintended by the driver is invalid.

[0007] Another aspect of the present disclosure provides a steering control method for controlling a steering device of a vehicle. The steering device has a structure in which a power transmission path is separated between an operation unit having an operation member and a steering unit configured to steer steered wheels. The steering control method includes: calculating a target steering correspondence value, which is a target value of a convertible value that can be converted into a steering angle of the steered wheels based on operation of the operation member; calculating the target steering correspondence value so that a ratio of a change in the steering angle to a change in operation amount of the operation member is greater than 1; generating a control signal for operating the steering unit based on the target steering correspondence value; and switching a control mode for operating the steering unit to an automatic driving control mode or a manual driving control mode. The vehicle is equipped with an external control device that outputs automatic driving instructions to realize automatic driving that automatically changes the direction of travel of the vehicle. The automatic driving control mode is a mode in which the automatic driving instructions are reflected in control for operating the steering unit. The manual driving control mode is a mode in which the automatic driving instructions are not reflected in the control of operating the steering unit. Switching the control mode includes executing an operation determination process to determine whether an operation condition for detecting a valid operation by the driver of the operating member is satisfied during the automatic driving control mode, and a mode switching process to switch from the automatic driving control mode to the manual driving control mode if the operation condition is satisfied. The operation determination process includes determining that an operation unintended by the driver is invalid. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic configuration diagram of a steering device of a first embodiment and a steering control device that controls the steering device. [Figure 2] FIG. 2 is a block diagram of the steering control device of FIG. 1. [Figure 3] 3 is a flowchart showing an example of a processing procedure for switching the control mode by operating the operation lever by the mode switching unit of FIG. 2 in the first embodiment. [Figure 4]3 is a flowchart showing an example of a processing procedure for switching the control mode by voice input by the mode switching unit of FIG. 2; [Figure 5] 10 is a flowchart showing an example of a processing procedure for mode switching processing by a mode switching unit of FIG. 2 according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] (First embodiment) A first embodiment of the steering control device will be described below with reference to the drawings. (Overall composition) As shown in Fig. 1, a steering control device 1 controls a steer-by-wire steering device 2. The steering device 2 changes the traveling direction of the vehicle by steering steered wheels 3 in response to an operation by the driver. The steering device 2 includes an operation unit 4 that is operated by the driver, and a steering unit 5 that steers the steered wheels 3. The steering device 2 has a structure in which the power transmission paths between the operation unit 4 and the steering unit 5 are mechanically separated.

[0010] The operation unit 4 includes an operating lever 11 operated by the driver and a base 12 that supports the operating lever 11 so that it can tilt. In this embodiment, the base 12 supports the operating lever 11 so that it can tilt laterally, i.e., in the left-right direction, of the vehicle, and the operating lever 11 tilts in the left-right direction when operated by the driver. In other words, the amount of operation by the driver is represented by the tilt angle of the operating lever 11 (hereinafter referred to as the lever tilt angle θl). In other embodiments, the base 12 may support the operating lever 11 so that it can tilt in the front-rear direction of the vehicle.

[0011] In the illustrated example, the operation unit 4 is equipped with a tilt angle sensor 13 that detects the lever tilt angle θl. The lever tilt angle θl is detected as a positive value when the operating lever 11 is tilted to the right and a negative value when the operating lever 11 is tilted to the left, but the opposite may also be true.

[0012] The operation unit 4 also includes a reaction force mechanism 12a that applies an operation reaction force, which is a force that resists the operation of the operation lever 11 by the driver. For example, the reaction force mechanism 12a is configured with a motor and / or a spring that generates an operation reaction force to be applied to the operation lever 11. When no force is applied to the operation lever 11 by the driver, the reaction force mechanism 12a applies an operation reaction force to maintain the operation lever 11 in a straight-ahead position. The straight-ahead position is a position corresponding to the vehicle's straight-ahead state. Furthermore, when the driver applies force to the operation lever 11 and the operation lever 11 no longer coincides with the straight-ahead position, and then the force is no longer applied, the reaction force mechanism 12a applies an operation reaction force to return the operation lever 11 to the straight-ahead position.

[0013] Furthermore, the operation unit 4 is equipped with an operation disable switch 14 that is operated by the driver. As will be described later, the operation disable switch 14 is used to disable any operation of the operation lever 11 by the driver. Disabling any operation of the operation lever 11 means that when the driver operates the operation lever 11, the operation is not reflected in the control of the steering device 2. The operation disable switch 14 outputs operation disable switch information Ss indicating the on / off state of the operation disable switch 14 to the steering control device 1. The operation disable switch 14 in this embodiment is a type of switch that continuously switches between on and off states when pressed once by the driver. The operation disable switch 14 is disposed on the operation lever 11, for example, but is not limited to this, and may be disposed in any position where the driver can operate it, such as on the base 12 or near the driver's seat. In the following description, "lever operation" means operation of the operation lever 11 by the driver.

[0014] The steering unit 5 includes a pinion shaft 21, a rack shaft 22 connected to the pinion shaft 21, a rack housing 23 that accommodates the rack shaft 22 so that it can reciprocate, and a rack-and-pinion mechanism 24 that has the pinion shaft 21 and the rack shaft 22. The rack-and-pinion mechanism 24 is configured such that pinion teeth 21a formed on the pinion shaft 21 mesh with rack teeth 22a formed on the rack shaft 22. As a result, the pinion shaft 21 rotates in response to the reciprocating motion of the rack shaft 22. Tie rods 26 are connected to both ends of the rack shaft 22 via ball joints 25. The ends of the tie rods 26 are connected to a knuckle (not shown) to which the steered wheels 3 are assembled.

[0015] Furthermore, steering unit 5 is equipped with steering actuator 31 that applies a steering force to rack shaft 22 that steers steerable wheels 3. In the example shown, steering actuator 31 is equipped with steering motor 32 and a power transmission mechanism 33 that transmits the torque of steering motor 32 to rack shaft 22. Power transmission mechanism 33 is equipped with a belt mechanism 34 and a ball screw mechanism 35. Steering actuator 31 transmits the rotation of steering motor 32 to ball screw mechanism 35 via belt mechanism 34, and applies the steering force to steerable wheels 3 by converting it into reciprocating motion of rack shaft 22 by ball screw mechanism 35.

[0016] In the steering device 2 configured in this manner, a steering force is applied from the steering actuator 31 in response to the lever operation. This causes the rack shaft 22 to reciprocate, changing the steering angle θi of the steered wheels 3. In other words, the steering actuator 31 steers the steered wheels 3 in response to the lever operation.

[0017] Steering control device 1 is connected to steering motor 32, and controls the operation of steering motor 32. Detection results of various sensors are input to steering control device 1. The various sensors include, for example, inclination angle sensor 13 mentioned above, vehicle speed sensor 41, and rotation angle sensor 42. Vehicle speed sensor 41 detects vehicle speed V, which is the traveling speed of the vehicle. Rotation angle sensor 42 detects rotation angle θt of the rotation shaft of steering motor 32 as a relative angle within a range of 360°. Operation disable switch information Ss of operation disable switch 14 is also input to steering control device 1. The detection results of these various sensors are examples of state variables. Steering control device 1 then controls the operation of steering motor 32 based on the input state variables.

[0018] Furthermore, the steering control device 1 is connected to an automatic driving control device 44 via an in-vehicle network 43 such as a CAN. The automatic driving control device 44 is an external control device provided separately from the steering control device 1 in a vehicle equipped with the steering device 2. The automatic driving control device 44 controls the operation of the steering unit 5 to automatically change the direction of travel of the vehicle. The automatic driving control device 44 determines the optimal control method based on the state of the vehicle at any given time. The automatic driving control device 44 controls the operation of the steering unit 5 in accordance with the required control method. For example, the automatic driving control device 44 instructs a change in the steering angle θi of the steered wheels 3 so as to take over driving while the vehicle is traveling.

[0019] The automatic driving control device 44 calculates an automatic driving control amount θad as a control amount for instructing a change in the steering angle θi of the steered wheels 3. The automatic driving control amount θad corresponds to an automatic driving instruction defined by an angle. The automatic driving control device 44 is connected to various detection devices (not shown) for detecting the state of the vehicle. For example, the various detection devices include a camera and a sensor for lane recognition. The automatic driving control device 44 calculates an automatic driving control amount θad for the automatic driving to be realized based on the state of the vehicle detected by the above detection devices. The automatic driving control amount θad is a control amount for instructing a change in the steering angle θi of the steered wheels 3 to change the traveling direction of the vehicle regardless of lever operation. The automatic driving control amount θad is output to the steering control device 1. The automatic driving control device 44 determines whether to realize automatic driving based on a request from the driver, for example, via a switch operation (not shown). The automatic driving control device 44 may be configured to output the automatic driving control amount θad to the steering control device 1 when automatic driving is to be realized based on the driver's request. The automatic driving control device 44 may calculate the automatic driving control amount θad regardless of whether automatic driving is realized or not. The automatic driving control device 44 configured in this manner does not need to output the automatic driving control amount θad to the steering control device 1 when automatic driving is not realized.

[0020] Furthermore, a voice input device 45 that detects voices from the driver is connected to the steering control device 1. The voice input device 45 is used to cancel automatic driving while the automatic driving is being realized. The voice input device 45 is a request means separate from the switch operation described above for canceling automatic driving while the automatic driving is being realized. A detection signal Sem indicating the detection result of the voices from the driver is output from the voice input device 45 to the steering control device 1. The voice input device 45 in this embodiment is placed on the operation lever 11, for example, but is not limited to this, and may be placed in any position where the voices of the driver can be detected, such as on the base 12 or near the driver's seat.

[0021] (Steering control device 1) The configuration of the steering control device 1 will be described in detail below. As shown in FIG. 2, the steering control device 1 includes a microcomputer 51 that outputs a control signal Mt, and a drive circuit 52 that supplies power to the steering motor 32 based on the control signal Mt.

[0022] The microcomputer 51, which is a processing circuit, can be configured as (1) one or more processors that operate according to a computer program (software), (2) one or more dedicated hardware circuits such as an application-specific integrated circuit (ASIC) that executes at least some of the various processes, or (3) a combination thereof. The processor includes a CPU and memory such as RAM and ROM, and the memory stores program code or instructions configured to cause the CPU to execute processes. Memory, i.e., non-transitory computer-readable medium, includes any available medium that can be accessed by a general-purpose or dedicated computer. Various controls by the microcomputer 51 are performed by the CPU executing programs stored in the memory at predetermined calculation cycles.

[0023] A typical PWM inverter having a plurality of switching elements such as FETs, IGBTs, etc. is employed for the drive circuit 52. The control signal Mt is a gate on / off signal that defines the on / off state of each switching element.

[0024] When microcomputer 51 outputs control signal Mt to drive circuit 52, power according to control signal Mt is supplied from the on-board power supply to steering motor 32. This causes steering motor 32 to rotate and, as described above, a steering force is applied to steered wheels 3. In this way, steering control device 1 controls the motor torque generated by steering motor 32 through the supply of power to steering motor 32, and steers steered wheels 3.

[0025] (Microcomputer 51) The configuration of the microcomputer 51 will be described in detail below. The microcomputer 51 outputs a control signal Mt by having each of the following control blocks execute calculation processing at each predetermined calculation cycle. The microcomputer 51 receives the vehicle speed V, lever tilt angle θl, rotation angle θt, operation disable switch information Ss, detection signal Sem, and automatic driving control amount θad. The microcomputer 51 generates and outputs the control signal Mt based on these state variables.

[0026] In detail, microcomputer 51 includes a steering response angle calculation unit 61 that calculates the steering response angle θp, a target steering response angle calculation unit 62 that calculates a target steering response angle θp* that is a target value of the steering response angle θp, a mode switching unit 63 that switches the control mode to determine whether or not automatic driving is realized, and a control signal generation unit 64 that generates a control signal Mt.

[0027] Rotation angle θt of steering motor 32 is input to steering response angle calculation unit 61. For example, steering response angle calculation unit 61 counts the number of rotations of steering motor 32 from the midpoint and calculates an integrated angle by integrating rotation angle θt with the midpoint set as zero degrees. Then, steering response angle calculation unit 61 calculates steering response angle θp by multiplying this integrated angle by a conversion coefficient based on the reduction ratio of belt mechanism 34, the lead of ball screw mechanism 35, and the rotational speed ratio of rack and pinion mechanism 24. In other words, steering response angle θp corresponds to the pinion angle, which is the rotation angle of pinion shaft 21, and the midpoint is the rotation angle of pinion shaft 21 when the vehicle is traveling straight. As described above, pinion shaft 21 rotates in response to the reciprocating motion of rack shaft 22, and therefore the rotation angle of pinion shaft 21, i.e., steering corresponding angle θp, corresponds to a steering corresponding value that is an actual value of a convertible value that can be converted into steering angle θi of steered wheels 3, and steering corresponding angle calculation unit 61 corresponds to a steering corresponding value calculation unit. The steering corresponding angle θp calculated by steering corresponding angle calculation unit 61 is output to control signal generation unit 64 via subtractor 65.

[0028] Vehicle speed V and lever inclination angle θl are input to target turning corresponding angle calculation unit 62. Target turning corresponding angle calculation unit 62 calculates target turning corresponding angle θp*, which is a target value of turning corresponding angle θp, based on these state variables. Target turning corresponding angle calculation unit 62 calculates target turning corresponding angle θp* so as to change the angle ratio α of the turning angle θi of steered wheels 3 to the lever inclination angle θl of operation lever 11. The angle ratio α is a value obtained by dividing the turning angle θi by the lever inclination angle θl (α=θi / θl). The angle ratio α is set to be greater than 1, and is set so that the absolute value of the target turning corresponding angle θp* increases as the absolute value of the lever inclination angle θl increases. Note that angle ratio α may be a value obtained by dividing the target turning corresponding angle θp* by the lever inclination angle θl. This is because the steering angle θi is a state variable obtained as a result of control by the target steering-corresponding angle θp*, and so has a correlation with the target steering-corresponding angle θp*. Also, the angle ratio α is set so that the absolute value of the target steering-corresponding angle θp* increases as the vehicle speed V decreases. In this embodiment, the target steering-corresponding angle θp* corresponds to a target steering-corresponding value that is a target value of a convertible value that can be converted into the steering angle θi of the steered wheels 3, and target steering-corresponding angle calculation unit 62 corresponds to a target steering-corresponding value calculation unit. The calculation process of the target steering-corresponding angle θp* by target steering-corresponding angle calculation unit 62 will be described later. The target steering-corresponding angle θp* is output to the control signal generation unit 64 via a subtractor 65 and an adder 66.

[0029] The lever tilt angle θl, the operation invalidation switch information Ss, the detection signal Sem, and the automatic driving control amount θad are input to the mode switching unit 63. Based on these state variables, the mode switching unit 63 determines whether or not automatic driving based on the automatic driving control amount θad is to be realized.

[0030] When mode switching unit 63 determines that automatic driving should be realized, it switches the control mode to automatic driving control mode. In automatic driving control mode, steering unit 5 is controlled so that the automatic driving control amount θad is reflected in the steering angle θi. When switching to automatic driving control mode, the automatic driving control amount θad is output to adder 66. In this case, adder 66 receives input of target steering corresponding angle θp* and automatic driving control amount θad. Adder 66 adds the target steering corresponding angle θp* and the automatic driving control amount θad to calculate target steering corresponding angle θpg* as a target value for the automatic driving control mode.

[0031] On the other hand, when mode switching unit 63 determines that automatic driving will not be achieved, it switches the control mode to manual driving control mode. In manual driving control mode, steering unit 5 is controlled so that the automatic driving control amount θad is not reflected in the steering angle θi. When switching to manual driving control mode, the automatic driving control amount θad is not output to adder 66. In this case, adder 66 inputs target steering corresponding angle θp*. Adder 66 uses target steering corresponding angle θp* as is to calculate target steering corresponding angle θpg* as a target value for the manual driving control mode. Target steering corresponding angle θpg* calculated by adder 66 is output to subtractor 65. Subtractor 65 calculates deviation Δθp by subtracting steering corresponding angle θp from target steering corresponding angle θpg*, and outputs the deviation Δθp to control signal generation unit 64.

[0032] Deviation Δθp is input to control signal generating section 64. Control signal generating section 64 generates control signal Mt based on this state variable. Control signal generating section 64 calculates the target steering torque by executing F / B calculation based on deviation Δθp. As an example, a PID control calculation is used for the F / B calculation, but this is not limitative and a PI control calculation or the like may also be used. Then, the F / B control section uses any well-known technology to generate control signal Mt that causes steering motor 32 to generate the target steering torque.

[0033] (Mode switching unit 63) The control mode switching process performed by the mode switching unit 63 will now be described in detail. During the automatic driving control mode, the mode switching unit 63 executes an operation determination process to determine whether an operation condition for detecting a valid lever operation is satisfied. As will be described later, the operation condition is a condition for determining whether the automatic driving control mode should be cancelled and switched to the manual driving control mode. The operation condition is set from the viewpoint of being able to detect that the lever operation is an operation intentionally performed by the driver. In other words, if the operation condition is not satisfied, the lever operation is detected as an operation unintentional by the driver. An operation unintentional by the driver that is detected as an operation for which the operation condition is not satisfied is determined to be invalid so as not to be included in the determination process from the viewpoint of determining whether the automatic driving control mode should be cancelled and switched to the manual driving control mode.

[0034] When the automatic driving control amount θad is input from the automatic driving control device 44, the mode switching unit 63 executes a process of switching the control mode to the automatic driving control mode. When the automatic driving control amount θad is no longer input or an operation condition is met during the automatic driving control mode, the mode switching unit 63 cancels the automatic driving control mode and switches the control mode to the manual driving control mode. Note that the mode switching unit 63 also switches the control mode to the manual driving control mode and cancels the automatic driving control mode when the voice input device 45 detects a voice input by the driver to cancel automatic driving during the automatic driving control mode.

[0035] Mode switching unit 63 outputs the automatic driving control amount θad during the automatic driving control mode. In this embodiment, switching to the automatic driving control mode means switching to a state in which the automatic driving control amount θad is output. As a result, steering control device 1 controls the operation of steering motor 32 using target steering-related angle θpg* in which the automatic driving control amount θad is reflected. In other words, the automatic driving control mode is a mode in which the automatic driving control amount θad for achieving automatic driving is reflected in the control for operating steering unit 5.

[0036] On the other hand, mode switching unit 63 does not output the automatic driving control amount θad during the manual driving control mode. In this embodiment, switching to the manual driving control mode means switching to a state in which the automatic driving control amount θad is not output. As a result, steering control device 1 controls the operation of steering motor 32 using target steering-related angle θpg* in which the automatic driving control amount θad is not reflected. In other words, the manual driving control mode is a mode in which the automatic driving control amount θad for achieving automatic driving is not reflected in the control for operating steering unit 5.

[0037] (Operating conditions) The mode switching unit 63 determines that the operation condition is met when the following condition is met: (a1) The operation invalidation switch 14 is in the OFF state.

[0038] (a2) It is not determined that the specific operation is one in which the change in the lever tilt angle θl of the operating lever 11 is instantaneously stopped. (a3) The lever inclination angle θl of the operating lever 11 has changed.

[0039] As shown in (a1), the operation conditions include conditions based on the on / off state of the operation disable switch 14. The conditions based on the on / off state of the operation disable switch 14 include an disable condition that is established when the operation disable switch 14 is in the on state. In other words, while the operation disable switch 14 is in the off state, i.e., while the disable condition is not established, the mode switching unit 63 determines that the lever operation is valid and is in an operation allowable state in which the operation condition is established. As shown in (a2) and (a3), the operation conditions include conditions based on the change in the lever tilt angle θl of the operating lever 11.

[0040] On the other hand, the mode switching unit 63 determines that the operation condition is not met when at least one of the above conditions is not met. That is, with respect to the condition (a1), the mode switching unit 63 performs processing so that the operation condition is not met by determining that the lever operation is invalid while the operation invalid switch 14 is in the on state, i.e., while the invalid condition is met, the mode switching unit 63 performs processing so that the operation condition is not met. In this embodiment, while the invalid condition is met, the mode switching unit 63 is in an operation invalid state in which the lever operation is determined to be invalid. Furthermore, with respect to the condition (a2), even if the invalid condition is not met, if the mode switching unit 63 determines that the lever operation is a specific operation, the mode switching unit 63 performs processing so that the operation condition is not met by determining that the operation is invalid. In this embodiment, the specific operation is an example of an operation unintended by the driver.

[0041] (Regarding specific operations) The mode switching unit 63 determines that the lever operation is a specific operation when the following condition is met:

[0042] (b1) The result of smoothing the time-series data Dt, which is the result of continuously detecting the value of the lever tilt angle θl, which is the operation amount of the operating lever 11, is equal to or greater than the change threshold value Lth. The sampling time is defined as a predetermined unit time going back from the present to the past. The time series data Dt is data obtained by continuously detecting the values of the lever tilt angle θl during the sampling time. In this embodiment, the leveling method is to calculate a moving average of the values of the lever tilt angle θl during the sampling time. The change threshold Lth is a value within a range that determines whether the change in the lever tilt angle θl of the operating lever 11 appears to settle out instantaneously. An instantaneous settlement is, for example, a change that occurs in a peak-like manner.

[0043] (b2) The operating speed ωl of the operating lever 11 is equal to or greater than the speed threshold ωlth. The speed threshold ωlth is a value within a range in which it can be determined that the driver has unintentionally touched the operation lever 11. The mode switching unit 63 of this embodiment calculates the operation speed ωl by differentiating the lever tilt angle θl. In other embodiments, a speed sensor may be provided in the operation unit 4, and the operation speed ωl may be detected from the speed sensor.

[0044] As in (b1), determining whether an operation is a specific operation includes a condition based on the result of comparing the magnitude of the result of smoothing time-series data obtained by continuously detecting the value of the lever tilt angle θl with a threshold value. As in (b2), determining whether an operation is a specific operation includes a condition based on the result of comparing the magnitude of an operation amount parameter indicating the change in the operation amount of the operating lever 11 with a threshold value.

[0045] (Regarding the process of switching control modes by operating the control lever) An example of a processing procedure in which the mode switching unit 63 switches the control mode by operating the lever while in the automatic driving control mode will be described with reference to the flowchart shown in FIG.

[0046] As shown in the figure, the mode switching unit 63 determines whether or not the automatic driving control mode is in effect (step 101), and if it determines that the automatic driving control mode is not in effect because the automatic driving control amount θad is not input (step 101: NO), the processing is terminated.

[0047] On the other hand, when the mode switching unit 63 determines that the automatic driving control mode is in effect because the automatic driving control amount θad has been input (step 101: YES), it acquires operation invalid switch information Ss (step 102). Subsequently, the mode switching unit 63 determines whether or not the invalid condition is met based on the operation invalid switch information Ss (step 103). In step 103, the mode switching unit 63 determines whether or not the operation invalid switch 14 is in the on state based on the operation invalid switch information Ss.

[0048] When the mode switching unit 63 determines that the invalid condition is satisfied because the operation invalid switch information Ss indicates the on state (step 103: YES), the mode switching unit 63 ends the processing. In this case, the mode switching unit 63 determines that the lever operation is invalid because the invalid condition is satisfied.

[0049] On the other hand, if the mode switching unit 63 determines that the invalid condition is not met because the operation invalid switch information Ss indicates an OFF state (step 103: NO), it acquires the lever tilt angle θl (step 104). Next, the mode switching unit 63 analyzes the time-series data Dt of the acquired value of the lever tilt angle θl (step 105). In step 105, the mode switching unit 63 calculates a moving average during the sampling time based on the time-series data Dt. Next, the mode switching unit 63 determines whether or not a specific operation has been detected (step 106). In step 106, the mode switching unit 63 determines whether or not the value of the moving average obtained based on the time-series data Dt is equal to or greater than a change threshold Lth. Also in step 106, the mode switching unit 63 calculates the operation speed ωl and determines whether or not the operation speed ωl is equal to or greater than a speed threshold ωlth.

[0050] When the mode switching unit 63 determines that the conditions (b1) and (b2) are satisfied because the value of the moving average obtained based on the time-series data Dt is equal to or greater than the change threshold Lth and the operation speed ωl is equal to or greater than the speed threshold ωlth, that is, that the operation is a specific operation (step 106: YES), the mode switching unit 63 ends the processing. In this case, the mode switching unit 63 determines that the lever operation that is determined to be a specific operation even though the invalid condition is not satisfied is invalid.

[0051] On the other hand, when the mode switching unit 63 determines that the condition (b1) or (b2) is not satisfied because the value of the moving average obtained based on the time-series data Dt is less than the change threshold Lth or the operation speed ωl is less than the speed threshold ωlth, i.e., that the operation is not a specific operation (step 106: NO), the mode switching unit 63 determines whether the operation condition is satisfied (step 107). In step 107, the mode switching unit 63 determines whether the lever tilt angle θl has changed based on the lever tilt angle θl acquired in step 104. In this case, the mode switching unit 63 determines whether the current value of the lever tilt angle θl acquired in the current cycle has changed from the previous value of the lever tilt angle θl acquired in the immediately preceding cycle (one cycle ago). Note that when the mode switching unit 63 reaches step 107, both the condition (a1) that the invalid condition is not satisfied (step 103: NO) and the condition (a2) that the lever operation is not a specific operation (step 106: NO) are satisfied.

[0052] When the mode switching unit 63 determines that the condition (a3) is not met because the lever tilt angle θl has not changed, that is, the operation condition is not met (step 107: NO), the process ends.

[0053] On the other hand, if the mode switching unit 63 determines that the condition (a3) is met because the lever tilt angle θl has changed, that is, that the operation condition is met (step 107: YES), it cancels the automatic driving control mode and switches the control mode to the manual driving control mode (step 108). In step 108, the mode switching unit 63 performs processing so that the automatic driving control amount θad will not be output thereafter, regardless of whether the automatic driving control amount θad has been input. The processing of step 107 corresponds to the operation determination processing, and the processing of step 108 corresponds to the mode switching processing.

[0054] (Processing for switching control modes via voice input) An example of a processing procedure in which the mode switching unit 63 switches the control mode in response to a voice input while in the automatic driving control mode will be described with reference to the flowchart shown in FIG.

[0055] As shown in the figure, the mode switching unit 63 determines whether or not voice input by the driver has been detected (step 111), and if it determines that voice input has not been detected because the detection signal Sem has not been input (step 111: NO), it terminates the processing.

[0056] On the other hand, when the mode switching unit 63 determines that a voice input has been detected based on the input of the detection signal Sem (YES in step 111), it determines whether or not the automatic driving control mode is in effect (step 112). Subsequently, when the mode switching unit 63 determines that the automatic driving control mode is not in effect based on the absence of an input of the automatic driving control amount θad (NO in step 112), it ends the processing.

[0057] On the other hand, when the mode switching unit 63 determines that the automatic driving control mode is active because the automatic driving control amount θad is input (step 112: YES), it cancels the automatic driving control mode and switches the control mode to the manual driving control mode (step 113). In step 113, the mode switching unit 63 switches the control mode from the automatic driving control mode to the manual driving mode regardless of whether the conditions (a1) to (a3) are met.

[0058] Next, the operation and effects of this embodiment will be described. (1-1) The mode switching unit 63 executes an operation determination process to determine whether an operation condition for detecting a valid lever operation during the automatic driving control mode is satisfied. The operation determination process includes a process for determining that a specific operation is invalid so that the operation condition is not satisfied by a lever operation unintentional by the driver. This prevents the driver from unintentionally touching the operating lever 11 and making the lever operation unintentional by the driver effective. This is particularly effective in a steering device 2 configured so that the angle ratio α is greater than 1. Therefore, switching from the automatic driving control mode to the manual driving control mode due to a lever operation unintentional by the driver during the automatic driving control mode is prevented.

[0059] (1-2) The operation determination process includes a process for determining whether the invalidation condition is satisfied. As a result, the operation determination process can determine that the lever operation is invalid if the invalidation condition is satisfied. Therefore, it is possible to easily realize a configuration for determining that an unintended lever operation by the driver is invalid.

[0060] (1-3) The operation determination process includes a process for determining that a specific operation, which is a momentary operation by the driver, is invalid. A momentary operation may have occurred due to the driver unintentionally touching the operating lever 11, etc. This is effective in appropriately detecting unintentional operations among the lever operations by the driver.

[0061] (1-4) The mode switching unit 63 detects a specific operation based on the result of comparing the magnitude of the change threshold Lth with the result of smoothing the time-series data Dt, which is the result of continuously detecting the lever tilt angle θl, which is the operation amount of the operating lever 11. This is effective in appropriately detecting a momentary operation as a specific operation.

[0062] (1-5) The mode switching unit 63 detects a specific operation based on the result of comparing the operation speed ωl, which indicates the change in the amount of operation of the operating lever 11, with the speed threshold ωlth. This is effective in appropriately detecting a momentary operation as a specific operation.

[0063] (Another embodiment of the first embodiment) Here, another embodiment of the steering control device of the first embodiment will be described. The mode switching unit 63 of this embodiment is configured to include a process for measuring, when detecting a specific operation, an operation time Ts during which the operating lever 11 does not match the straight-ahead position, instead of the time-series data Dt of each of the above embodiments.

[0064] Specifically, the mode switching unit 63 calculates the operation time Ts as processing corresponding to step 105. Furthermore, the mode switching unit 63 determines whether the operation time Ts is less than a time threshold Tth as processing corresponding to step 106.

[0065] The mode switching unit 63 can determine that a specific operation has been detected when the operation time Ts is less than the time threshold Tth (step 106: YES). On the other hand, the mode switching unit 63 can determine that a specific operation has not been detected when the operation time Ts is equal to or greater than the time threshold Tth (step 106: NO).

[0066] According to this embodiment, it is effective in appropriately detecting a momentary operation as a specific operation, which is the same as the above-mentioned effect (1-4). (Second embodiment) Next, a second embodiment of the steering control device will be described with reference to the drawings. For the sake of convenience, the same components as those in the first embodiment will be assigned the same reference numerals as those in the first embodiment, and the description thereof will be omitted.

[0067] As shown by the two-dot chain line in Fig. 1, the operation unit 4 is provided with a pressure sensor 15 that detects the driver's grip of the operation lever 11, instead of the operation invalidation switch 14 of the first embodiment. As will be described later, the pressure sensor 15 is used to validate the lever operation. In this embodiment, the lever operation is validated when the pressure sensor 15 detects the driver's grip of the operation lever 11.

[0068] As shown in parentheses in FIG. 2 , the pressure sensor 15 outputs pressure sensor information Sst indicating the on / off state of the pressure sensor 15 to the steering control device 1, instead of the operation invalidation switch information Ss of the first embodiment. The pressure sensor 15 of this embodiment is a sensor that detects the on / off state depending on whether the driver grips the control lever 11 and touches the detection unit of the pressure sensor 15. The pressure sensor 15 detects the on state when the driver grips the control lever 11 and touches the detection unit of the pressure sensor 15. The on state of the pressure sensor 15 can detect that the lever operation is intended by the driver when there is a lever operation. On the other hand, the pressure sensor 15 detects the off state when the driver does not grip the control lever 11 and does not touch the detection unit of the pressure sensor 15. The off state of the pressure sensor 15 can detect that the lever operation is not intended by the driver when there is a lever operation. The pressure sensor 15 is disposed, for example, on the control lever 11.

[0069] (Operating conditions) The operating conditions of this embodiment include (a1r) instead of (a1) in the first embodiment. The operating conditions of this embodiment include (a2) and (a3) in the first embodiment. That is, the operating conditions of this embodiment are (a1r), (a2), and (a3).

[0070] Specifically, the condition (a1r) is that the pressure sensor 15 is in the ON state. As in (a1r), the operation conditions include conditions based on the ON / OFF state of the pressure sensor 15. The conditions based on the ON / OFF state of the pressure sensor 15 include set conditions that are met when the pressure sensor 15 is in the ON state. In other words, when the pressure sensor 15 is in the ON state, that is, when the set conditions are met, the mode switching unit 63 determines that the lever operation is valid and is in an operation allowable state in which the operation conditions are met.

[0071] On the other hand, the mode switching unit 63 determines that the operation condition is not met when the above condition is not met. That is, with regard to the condition (a1r), when the pressure sensor 15 is in the off state, i.e., when the set state is not met, the mode switching unit 63 determines that the lever operation is invalid, thereby processing so that the operation condition is not met. In this embodiment, when the set condition is not met, it is an operation invalid state in which lever operation unintended by the driver is determined to be invalid. Furthermore, with regard to the condition (a2), when the pressure sensor 15 is in the on state, even if the set condition is met, if the mode switching unit 63 determines that the lever operation is a specific operation, it processes so that the operation condition is not met by determining that the operation is invalid.

[0072] (Regarding the process of switching control modes by operating the control lever) An example of a processing procedure in which the mode switching unit 63 of this embodiment switches the control mode by operating the lever while in the automatic driving control mode will be described with reference to the flowchart shown in FIG.

[0073] As shown in the figure, the mode switching unit 63 determines whether or not the automatic driving control mode is in effect (step 201). In step 201, the mode switching unit 63 performs the same process as in step 101 in Fig. 3. When the mode switching unit 63 determines that the automatic driving control mode is not in effect because the automatic driving control amount θad has not been input (step 201: NO), the mode switching unit 63 ends the process.

[0074] On the other hand, when the mode switching unit 63 determines that the automatic driving control mode is set based on the input of the automatic driving control amount θad (step 201: YES), it acquires pressure sensor information Sst (step 202). Subsequently, the mode switching unit 63 determines whether or not the set condition is met based on the pressure sensor information Sst (step 203). In step 203, the mode switching unit 63 determines whether or not the pressure sensor 15 is in the ON state based on the pressure sensor information Sst.

[0075] When the mode switching unit 63 determines that the set condition is not satisfied because the pressure sensor information Sst indicates the OFF state (step 203: NO), the mode switching unit 63 ends the process. In this case, the mode switching unit 63 determines that the lever operation is invalid because the pressure sensor 15 is in the OFF state.

[0076] On the other hand, if the mode switching unit 63 determines that the set condition is met because the pressure sensor information Sst indicates an ON state (step 203: YES), it acquires the lever tilt angle θl (step 204). Next, the mode switching unit 63 analyzes the acquired time-series data Dt of the lever tilt angle θl (step 205). In step 205, the mode switching unit 63 performs the same process as in step 105 of FIG. 3.

[0077] Next, the mode switching unit 63 determines whether or not a specific operation has been detected (step 206). In step 206, the mode switching unit 63 performs the same process as in step 106 in Fig. 3. If the mode switching unit 63 determines that the operation is a specific operation (step 206: YES), the mode switching unit 63 ends the process. In this case, the mode switching unit 63 determines that the lever operation, for which the set condition is met but which is determined to be a specific operation, is invalid.

[0078] On the other hand, if the mode switching unit 63 determines that the operation is not a specific operation (step 206: NO), it determines whether or not the operation condition is met (step 207). In step 207, the mode switching unit 63 performs the same process as step 107 in Fig. 3. If the mode switching unit 63 determines that the operation condition is not met (step 207: NO), it ends the process.

[0079] On the other hand, if the mode switching unit 63 determines that the operation condition is met (step 207: YES), it cancels the automatic driving control mode and switches the control mode to the manual driving control mode (step 208). In step 208, the mode switching unit 63 performs the same process as in step 108 in FIG. 3.

[0080] According to this embodiment, the following actions and effects are achieved. (2-1) The operation determination process includes a process for determining whether a set condition is met. As a result, if the set condition is not met, the operation determination process can determine that the lever operation is invalid. Therefore, it is possible to easily realize a configuration for determining that an unintended lever operation by the driver is invalid.

[0081] (Other embodiments) The above-described embodiments can be modified as follows: The above-described embodiments and the following modifications can be combined with each other within the scope of technical compatibility.

[0082] In the first embodiment, the configuration of the operation invalidation switch 14 may be omitted. In this case, the process of step 103 in the process of FIG. In the first embodiment, the configuration of the pressure sensor 15 in the second embodiment may be added. In this case, in the process of Fig. 3, a process corresponding to step 203 in Fig. 5 may be added before or after the process of step 103.

[0083] In the first embodiment, the type of the operation invalidating switch 14 can be changed as appropriate, for example, to a touch sensor type. In the first embodiment, the processing procedure by the mode switching unit 63 is not limited to the procedures shown in Figures 3 and 4, and can be modified as appropriate. For example, the processing of step 101 in Figure 3 may be configured to be executed after the processing of step 107: YES. This also applies to the second embodiment. In other words, the processing of step 201 in Figure 5 may be configured to be executed after the processing of step 207: YES.

[0084] In the first embodiment, the processing of step 106 in Fig. 3 may be deleted from the processing by the mode switching unit 63. This also applies to the second embodiment. In other words, the processing of step 206 in Fig. 5 may be deleted.

[0085] In the second embodiment, the pressure sensor 15 may be omitted. In this case, the process of step 203 in the process of FIG. In the second embodiment, the type of the pressure sensor 15 can be changed as appropriate, for example, to a type in which the on / off state is switched depending on whether the operating lever 11 is gripped and pressed.

[0086] In each of the above embodiments, when detecting a specific operation, the mode switching unit 63 may use other elements instead of the operation speed ωl, or may use a combination of other elements. Possible other elements include, for example, the operation acceleration, which is the amount of change in the operation speed ωl, the steering response angle θp, or the steering speed, which is the amount of change in the steering response angle θp. Furthermore, the other element may be the driver's operating force on the operating lever 11. For example, the operating lever 11 may be equipped with a torque sensor that detects the driver's operating force on the operating lever 11.

[0087] In each of the above embodiments, the mode switching unit 63 may determine that a specific operation has been detected when either the condition (b1) or (b2) is met. In each of the above embodiments, when detecting a specific operation, the mode switching unit 63 may select only the condition (b1) and delete the condition (b2), or may select only the condition (b2) and delete the condition (b1).

[0088] In each of the above embodiments, when detecting a specific operation, the mode switching unit 63 may use either the time series data Dt or the operation time Ts, which is the time during which the operating lever 11 is in a state that does not match the straight-ahead position.

[0089] In each of the above embodiments, the change threshold value Lth may be varied depending on the operation to be detected as a specific operation. For example, an operation that lengthens or shortens the time period during which the change in the driver's lever operation settles down can be detected as a specific operation. The same applies to the time threshold value Tth or the speed threshold value ωlth.

[0090] In each of the above embodiments, the change threshold Lth may be changed in accordance with the vehicle running state, such as the vehicle speed V. This also applies to the time threshold Tth or the speed threshold ωlth. In each of the above embodiments, the automatic driving control device 44 may generate a torque control amount having a torque dimension as the automatic driving control amount θad. In this case, the torque control amount having a torque dimension may be converted into a value having an angle dimension, and then reflected in the steering angle θi.

[0091] In each of the above embodiments, the autonomous driving function can be realized not only as a function to take over driving while the vehicle is traveling, but also as a function to provide various driving assistance functions to further improve the comfort of the vehicle. Examples of driving assistance functions include a function to prevent the vehicle from leaving its lane and a function to assist in emergency avoidance.

[0092] In each of the above embodiments, the configuration of the voice input device 45 may be omitted. In this case, the process in FIG. 4 may be omitted. In each of the above embodiments, the emergency request means for canceling the automatic driving can be appropriately changed, for example, by providing a switch operated by the driver instead of the voice input device 45.

[0093] In each of the above embodiments, the steering-corresponding angle calculation unit 61 may be omitted. In this case, for example, the steering-corresponding angle θp, which is the rotation angle, may be input from a sensor that detects the rotation angle of the pinion shaft 21. The sensor may detect the rotation angle of the pinion shaft 21 as an absolute angle exceeding the range of 360°.

[0094] In each of the above embodiments, if the reaction force mechanism 12a is configured by a motor, the lever tilt angle θl may be detected based on the rotation angle of the motor. In the above embodiments, the convertible value that can be converted into the steering angle θi of the steered wheels 3 is the rotation angle of the pinion shaft 21. However, this is not limited to this. For example, the convertible value may be the stroke amount of the rack shaft 22 or the steering angle θi itself.

[0095] In each of the above embodiments, the operating lever 11 is tiltably supported on the base 12, but this is not limiting and, for example, the operating lever 11 may be supported slidably relative to the base 12. In this case, the amount of operation by the driver is represented by the amount of sliding of the operating lever 11. The operating lever 11 may be used to control the driving / braking of the vehicle in addition to controlling the steering angle θi of the steered wheels 3.

[0096] In each of the above embodiments, the operation unit 4 may be provided with a steering wheel operated by the driver as an operation member instead of the operation lever 11. In this case, the operation unit 4 may be provided with a steering wheel in addition to the operation lever 11. The steering device 2 has a linkless structure in which power transmission between the operation unit 4 and the steering unit 5 is separated, but this is not limited to this. If a steering wheel is provided, the steering device 2 may be provided with a structure in which power transmission between the operation unit 4 and the steering unit 5 can be separated by a clutch.

[0097] In each of the above embodiments, steering actuator 31 transmits the rotation of steering motor 32 to ball screw mechanism 35 via belt mechanism 34, but this is not limiting. For example, steering actuator 31 may be configured so that the rotation of steering motor 32 is transmitted to ball screw mechanism 35 via a gear mechanism. Also, steering actuator 31 may be configured so that steering motor 32 directly rotates ball screw mechanism 35. Furthermore, steering unit 5 may be configured to include a second rack-and-pinion mechanism, and steering actuator 31 may be configured so that the rotation of steering motor 32 is converted into reciprocating motion of rack shaft 22 by the second rack-and-pinion mechanism, thereby applying a steering force to steering unit 5.

Claims

1. A steering control device that controls a steering device of a vehicle, the steering device has a structure in which a power transmission path between an operation unit having an operation member and a steering unit configured to steer steered wheels is separated, The steering control device includes: a target steering corresponding value calculation unit configured to calculate a target steering corresponding value, which is a target value of a convertible value that can be converted into a steering angle of the steered wheels, based on the operation of the operating member, and to calculate the target steering corresponding value so that a ratio of a change in the steering angle to a change in the operation amount of the operating member becomes greater than 1; a control signal generating unit configured to generate a control signal for operating the steering unit based on the target steering corresponding value; a mode switching unit that switches a control mode for operating the steering unit between an automatic driving control mode and a manual driving control mode, the vehicle is equipped with an external control device that outputs an instruction for automatic driving to realize automatic driving that automatically changes the traveling direction of the vehicle; the automatic driving control mode is a mode in which the automatic driving instruction is reflected in control for operating the steering unit, The manual driving control mode is a mode in which the instruction for automatic driving is not reflected in the control for operating the steering unit, The mode switching unit an operation determination process for determining whether an operation condition for detecting a valid operation by the driver on the operation member is satisfied during the automatic driving control mode; When the operation condition is satisfied, a mode switching process is executed to switch from the automatic driving control mode to the manual driving control mode, The operation determination process includes: A process of determining whether a mode state condition of the automatic driving control mode is satisfied; a process for determining whether an operation state condition, which is a state in which a valid operation by the driver to the operation member is detected, is satisfied on the condition that at least the mode state condition is satisfied, and determining whether the operation state condition is satisfied or not based on a condition other than the operation by the driver to the operation member; a process of determining that the driver's operation is invalid based on at least the conditions that the mode state condition is satisfied and the operation state condition is not satisfied; and determining that an operation unintended by the driver is invalid, based on at least conditions that the mode state condition is satisfied and the operation state condition is satisfied.

2. The steering control device according to claim 1, the operation state condition is a condition that is established when an invalid condition that is established under a condition other than the operation by the driver of the operation member is not established, The operation determination process includes: a process of determining that the driver's operation is invalid based on at least the conditions that the mode state condition is satisfied and the invalid condition is satisfied, thereby causing the operation state condition to not be satisfied; A steering control device including a process for determining whether the operation condition is satisfied, based on at least the conditions that the mode state condition is satisfied and that the operation state condition is satisfied when the invalid condition is not satisfied.

3. The steering control device according to claim 1 or 2, the operation state condition is a condition that is satisfied when a set condition that is satisfied under a condition separate from the operation of the operation member by the driver is satisfied, The operation determination process includes: a process of determining whether the operation condition is satisfied, based on at least the conditions that the mode state condition is satisfied and that the operation state condition is satisfied when the setting condition is satisfied; A steering control device including a process for determining that the driver's operation is invalid based on at least the conditions that the mode state condition is satisfied and that the operation state condition is not satisfied due to the setting condition not being satisfied.

4. The steering control device according to any one of claims 1 to 3, The operation determination process includes a process of determining that a specific operation that appears in a manner in which the change in the driver's operation subsides instantaneously is invalid, based on at least the conditions that the mode state condition and the operation state condition are satisfied.

5. The steering control device according to claim 4, The operation determination process includes: a process of analyzing time-series data obtained by continuously detecting the operation amount of the operation member; and detecting the specific operation based on a result of analyzing the time-series data.

6. The steering control device according to claim 5, the process of analyzing the time series data includes a process of smoothing the time series data, A steering control device, wherein the process of detecting the specific operation includes a process of detecting the specific operation based on a result of comparing the leveling result with a threshold value.

7. The steering control device according to claim 4, The operation determination process includes: a process of measuring a time during which the operation amount of the operating member does not coincide with a straight driving position, which is a position corresponding to a straight driving state of the vehicle; detecting the specific operation based on the result of measuring the time; A steering control device, wherein the process of detecting the specific operation includes a process of detecting the specific operation based on a result of comparing the result of measuring the time with a threshold value.

8. The steering control device according to any one of claims 5 to 7, A steering control device, wherein the process of detecting the specific operation includes a process of detecting the specific operation based on a result of comparing a magnitude of an operation amount parameter indicating a change state of the operation amount with a threshold value.

9. A steering control method for controlling a steering device of a vehicle, comprising: the steering device has a structure in which a power transmission path between an operation unit having an operation member and a steering unit configured to steer steered wheels is separated, The steering control method includes: calculating a target steering correspondence value, which is a target value of a convertible value that can be converted into a steering angle of the steered wheels, based on the operation of the operating member, and calculating the target steering correspondence value so that a ratio of a change in the steering angle to a change in the operation amount of the operating member becomes greater than 1; generating a control signal for operating the steering unit based on the target steering corresponding value; Switching a control mode for operating the steering unit to an automatic driving control mode or a manual driving control mode, the vehicle is equipped with an external control device that outputs an instruction for automatic driving to realize automatic driving that automatically changes the traveling direction of the vehicle; the automatic driving control mode is a mode in which the automatic driving instruction is reflected in control for operating the steering unit, The manual driving control mode is a mode in which the instruction for automatic driving is not reflected in the control for operating the steering unit, The switching of the control mode includes: an operation determination process for determining whether an operation condition for detecting a valid operation by the driver on the operation member is satisfied during the automatic driving control mode; When the operation condition is satisfied, a mode switching process is executed to switch from the automatic driving control mode to the manual driving control mode, The operation determination process includes: A process of determining whether a mode state condition of the automatic driving control mode is satisfied; a process for determining whether an operation state condition, which is a state in which a valid operation by the driver to the operation member is detected, is satisfied on the condition that at least the mode state condition is satisfied, and determining whether the operation state condition is satisfied or not based on a condition other than the operation by the driver to the operation member; a process of determining that the driver's operation is invalid based on at least the conditions that the mode state condition is satisfied and the operation state condition is not satisfied; and executing a process of determining that an operation unintended by the driver is invalid, based on at least the conditions that the mode state condition is satisfied and the operation state condition is satisfied.

Images