Steering control device

Abstract

A steering control device (1) includes a reaction force control device (1A) and a turning control device (1B). A reaction force motor (12) is controlled. The turning control device controls a turning motor (31). The reaction force control device can select a normal mode or a play mode as a steering control mode. The normal mode is selected when a vehicle is run, and the play mode is selected when simulated driving or the like is performed using the vehicle. When vehicle power is on, the reaction force control device executes, as part of processing in the normal mode, preparation processing including midpoint learning processing for learning a neutral position of an operation element. A transition condition from the normal mode to the play mode includes that the midpoint learning processing has been completed.

Description

Steering control system

[0001] This disclosure relates to a steering control device.

[0002] Conventionally, automobiles that allow for entertainment inside the vehicle have been proposed. For example, the automobile described in Patent Document 1 has a driving mode and an entertainment mode. The driving mode is the mode for driving the automobile. The entertainment mode includes a game mode for enjoying games and a radio control mode for enjoying radio-controlled devices. The user of the automobile selects either the driving mode or the entertainment mode when starting the automobile.

[0003] Automobiles are equipped with a steering system that separates power transmission between the steering wheel and the steering wheels, a system known as steer-by-wire. The steering system has a reaction motor and a steering motor. The reaction motor generates the steering reaction force applied to the steering shaft. The steering motor generates the steering force that turns the steering wheels. The steering system controller controls the reaction motor and the steering motor according to the steering state of the steering wheel.

[0004] When the car user selects a driving mode, the controller controls the steering motor so that the steering wheels turn according to the steering wheel's position. When the car user selects an entertainment mode, the controller controls the steering motor so that the steering wheels do not turn regardless of the steering wheel's position. The car user can feel the steering feedback through the steering wheel according to the content of the entertainment activity.

[0005] International Publication No. 2024 / 069692

[0006] The steering system controller needs to transition between steering control modes appropriately depending on the vehicle's mode.

[0007] A steering control device according to one aspect of the present disclosure includes a reaction force control device configured to control a reaction force motor that generates a reaction force applied to a vehicle's control element, and a steering control device configured to control a steering motor that generates a steering force applied to a steering shaft from which power transmission to the control element is separated. The reaction force control device is configured to allow selection of a normal mode and a play mode as steering control modes. The normal mode is the mode selected when the vehicle is actually driven. The play mode is the mode selected when the vehicle is used for simulated driving or when the vehicle is used to operate a simulated vehicle. The reaction force control device is configured to perform a preparation process, including a midpoint learning process for learning the neutral position of the control element, as part of the processing in the normal mode when the vehicle power is turned on. The transition condition from the normal mode to the play mode includes the completion of the midpoint learning process.

[0008] Figure 1 is a configuration diagram of a steering device equipped with a steering control device according to the first embodiment. Figure 2 is a flowchart showing the state transitions of the reaction force control device in Figure 1. Figure 3 is a flowchart showing the state transitions of the steering control device in Figure 1. Figure 4 is a flowchart showing the state transitions of the reaction force control device according to the second embodiment. Figure 5 is a flowchart showing the state transitions of the steering control device according to the second embodiment. Figure 6 is a flowchart showing the state transitions of the reaction force control device according to the third embodiment. Figure 7 is a flowchart showing the state transitions of the steering control device according to the third embodiment.

[0009] <First Embodiment> The steering control device according to the first embodiment will be described. As shown in Figure 1, the steering control device 1 controls a steer-by-wire type steering device 2. The steering device 2 has a steering mechanism 3 and a steering mechanism 4. The steering mechanism 3 is a mechanism that is steered by the driver via the steering wheel 5. The steering wheel is the vehicle's control element. The steering mechanism 4 is a mechanism that steers the vehicle's steering wheels 6 in response to the steering of the steering wheel 5. The steering control device 1 controls the steering mechanism 3 and the steering mechanism 4.

[0010] The steering control device 1 includes a reaction force control device 1A and a steering control device 1B. The reaction force control device 1A controls the steering mechanism 3, and the steering control device 1B controls the steering mechanism 4. The reaction force control device 1A and the steering control device 1B exchange information with each other via a communication line. The reaction force control device 1A and the steering control device 1B operate in coordination based on the information exchanged with each other.

[0011] However, depending on the product specifications, the reaction force control device 1A and the steering control device 1B may be integrated into a single steering control device 1. In this case, the reaction force control device 1A corresponds to the reaction force control unit, and the steering control device 1B corresponds to the steering control unit.

[0012] The steering mechanism 3 includes a steering shaft 11, a reaction motor 12, and a reduction gear 13. The steering wheel 5 is rotatably connected to the steering shaft 11. The reaction motor 12 is the source of the steering reaction force applied to the steering shaft 11. The steering reaction force is a force in the opposite direction to the steering direction of the steering wheel 5. The reaction motor 12 is, for example, a three-phase brushless motor. The reduction gear 13 reduces the rotation of the reaction motor 12 and transmits the reduced rotation to the steering shaft 11.

[0013] The steering mechanism 4 includes a pinion shaft 21, a steering shaft 22, and a housing 23. The housing 23 rotatably supports the pinion shaft 21. The housing 23 also reciprocates the steering shaft 22. Power transmission between the steering shaft 22 and the steering wheel 5 is isolated. The pinion shaft 21 is positioned to intersect the steering shaft 22. The pinion teeth 21a of the pinion shaft 21 mesh with the rack teeth 22a of the steering shaft 22. Tie rods 25 are connected to both ends of the steering shaft 22 via rack ends 24, which are ball joints. The ends of the tie rods 25 are connected to knuckles (not shown) to which the steering wheel 6 is assembled.

[0014] The steering mechanism 4 comprises a steering motor 31, a transmission mechanism 32, and a conversion mechanism 33. The steering motor 31 is the source of the steering force applied to the steering shaft 22. The steering force is the force used to steer the steering wheel 6. The steering motor 31 is, for example, a three-phase brushless motor. The transmission mechanism 32 is, for example, a belt drive mechanism. The transmission mechanism 32 transmits the rotation of the steering motor 31 to the conversion mechanism 33. The conversion mechanism 33 is, for example, a ball screw mechanism. The conversion mechanism 33 converts the rotation transmitted via the transmission mechanism 32 into axial motion of the steering shaft 22.

[0015] As the steering shaft 22 moves axially, the steering angle θ of the steering wheel 6 changes. ｗ This is changed. The pinion teeth 21a of the pinion shaft 21 mesh with the rack teeth 22a of the steering shaft 22, and therefore rotate in conjunction with the movement of the steering shaft 22. The pinion shaft 21 is a shaft that rotates in conjunction with the steering action of the steering wheel 6.

[0016] The reaction force control device 1A and the steering control device 1B each have a processing circuit that includes one of the following three configurations A1, A2, and A3. The processing circuit of the reaction force control device 1A is the first processing circuit, and the processing circuit of the steering control device 1B is the second processing circuit.

[0017] A1. One or more processors that operate according to a computer program, which is software. A processor includes a CPU (Central Processing Unit) and memory. A2. One or more dedicated circuits, such as application-specific integrated circuits (ASICs), that perform at least some of the various processes. An ASIC may include a CPU and memory.

[0018] A3. A circuit combining configurations A1 and A2. Memory is a medium readable by a computer and stores programs that describe processes or instructions for the computer. In this embodiment, the computer is the CPU. Memory includes RAM (Random Access Memory) and ROM (Read Only Memory). The CPU performs various controls by executing the programs stored in memory at predetermined calculation cycles.

[0019] The reaction force control device 1A and the steering control device 1B each acquire detection results from on-board sensors. The reaction force control device 1A acquires detection results from, for example, the vehicle speed sensor 41, the torque sensor 42, and the first rotation angle sensor 43. The steering control device 1B acquires detection results from, for example, the second rotation angle sensor 44.

[0020] The vehicle speed sensor 41 detects the vehicle speed V. The vehicle speed V is a state variable that reflects the vehicle's driving state. The torque sensor 42 is installed on the steering shaft 11. The torque sensor 42 is located on the steering wheel 5 side of the steering shaft 11 relative to the connection portion of the reduction gear 13. The torque sensor 42 detects the steering torque T applied to the steering shaft 11. ｈ It detects steering torque T. ｈ This is calculated based on the amount of twist of the torsion bar 42a provided on the steering shaft 11. Steering torque T ｈ This is a state variable that reflects the steering state of the steering wheel 5.

[0021] The first rotation angle sensor 43 is provided on the reaction motor 12. The first rotation angle sensor 43 measures the rotation angle θ of the reaction motor 12. ａ The second rotation angle sensor 44 is provided on the steering motor 31. The second rotation angle sensor 44 detects the rotation angle θ of the steering motor 31. ｂ Detects.

[0022] The reaction force control device 1A performs reaction force control. The reaction force control controls the steering torque T ｈIt is control to generate a steering reaction force corresponding to in the reaction force motor 12. The reaction force control device 1A, for example, uses the vehicle speed V detected by the vehicle speed sensor 41, the steering torque T detected by the torque sensor 42 ｈ , and the rotation angle θ of the reaction force motor 12 detected by the first rotation angle sensor to control the operation of the reaction force motor 12. The reaction force control device 1A controls the power supply to the reaction force motor 12 so as to generate a steering reaction force corresponding to the steering torque T ａ in the reaction force motor 12. ｈ

[0023] The steering control device 1B executes steering control. The steering control is control to steer the steered wheels 6 according to the steering state of the steering wheel 5. The steering control device 1B, for example, controls the operation of the steering motor 31. The steering control device 1B uses the rotation angle θ of the steering motor 31 detected by the second rotation angle sensor 44 to control the operation of the steering motor 31. The steering control device 1B controls the power supply to the steering motor 31 so that the steered wheels 6 are steered according to the steering state of the steering wheel 5. ｂ

[0024] The reaction force control device 1A is interconnected with the vehicle control device 52 via the in-vehicle network 51. The vehicle control device 52 has a processing circuit including any one of the previous three configurations A1, A2, A3, similar to the reaction force control device 1A. The in-vehicle network is, for example, a CAN (Controller Area Network). The reaction force control device 1A and the vehicle control device 52 exchange information with each other via the in-vehicle network 51. The reaction force control device 1A controls the drive of the reaction force motor 12 based on the information exchanged with the vehicle control device 52.

[0025] ​​The vehicle control device 52 controls various devices mounted on the vehicle. These devices include, for example, a powertrain, a braking system, and a display device. The powertrain includes a vehicle drive source and a power transmission mechanism. The drive source is, for example, at least one of an engine and a motor. The power transmission mechanism is a mechanism that transmits the power generated by the drive source to the drive wheels. The braking system generates a braking force to decelerate or stop the moving vehicle. The display device is a display installed in the passenger compartment. The display device may be a touch panel. By touching the display on the touch panel screen, it is possible to input data or instruct the operation of on-board equipment. The display device is both an input device and an output device.

[0026] When the vehicle power is turned on, the vehicle control device 52 starts executing a predetermined startup preparation. The startup preparation includes, for example, an initial check of the vehicle control device 52 and the processing required to start the vehicle's powertrain. The initial check is an initial inspection performed when the vehicle power is turned on, and includes, for example, hardware checks, CPU initialization, and initialization of variables or flags. After the execution of the initial check is completed, the vehicle control device 52 starts the powertrain startup process. The startup process is mainly the process of starting the drive source for the vehicle. When the execution of the powertrain startup process is completed, the vehicle control device 52 turns on the ready flag.

[0027] The Ready flag indicates whether the vehicle is ready to drive, including the completion of the powertrain start-up process. When the Ready flag is turned on, the vehicle is ready to drive. When the Ready flag is turned off, the vehicle is not ready to drive.

[0028] In addition to the first function of controlling the actual vehicle's driving, the vehicle control device 52 has a second function of controlling the driving of a virtual vehicle. For example, after turning on the vehicle's power, the user of the vehicle can select either the first function or the second function by operating a selection switch. The selection switch may be a mechanical switch provided in the vehicle interior or a virtual switch displayed on the screen of a display device such as a touch panel.

[0029] When the second function is selected, the vehicle control device 52 can perform various simulations using the actual vehicle. The simulations include, for example, simulations for educational training or virtual driving experiences such as driving simulators, and simulations for entertainment such as racing games using virtual vehicles. The virtual vehicle may be, for example, a virtual vehicle displayed on the screen of a display device. The vehicle control device 52 controls the driving of the virtual vehicle displayed on the screen according to the operations of various devices such as the steering wheel 5, the accelerator pedal, and the brake pedal.

[0030] The vehicle control device 52 generates steering mode information according to whether the first function or the second function is selected. The steering mode information is a command to the steering control device 1 and indicates which of the first function or the second function is selected. The steering mode information may be, for example, a flag, The vehicle control device 52 sets the value of the steering mode information to "0" when the first function is selected. The vehicle control device 52 sets the value of the steering mode information to "1" when the second function is selected.

[0031] The reaction force control device 1A takes in the steering mode information generated by the vehicle control device 52 via the in-vehicle network 51. The steering control device 1B takes in the steering mode information from the reaction force control device 1A via, for example, a communication line. However, depending on the product specifications, the steering control device 1B may take in the steering mode information from the vehicle control device 52 via the in-vehicle network 51.

[0032] The reaction force control device 1A switches the steering control mode according to the steering mode information. The steering control mode includes, for example, a normal mode and a play mode. The normal mode is the steering control mode selected when the first function of the vehicle control device 52 is selected, that is, when the vehicle is actually driven. When the steering control mode is the normal mode, the reaction force control device 1A performs normal reaction force control, and the steering control device 1B performs normal steering control. That is, in the normal mode, the reaction force control device 1A applies a steering torque T to the steering wheel 5. ｈ This mode controls the reaction force motor 12 so that a steering reaction force is applied accordingly. When the steering control mode is the normal mode, the steering control device 1B controls the steering motor 31 so that the steering wheels 6 turn according to the steering state of the steering wheel 5. Steering torque T ｈ A corresponding steering reaction force is applied to the steering wheel 5, making it possible to provide the vehicle user with a suitable sense of feedback. The steering wheels 6 steer according to the steering state of the steering wheel 5.

[0033] The play mode is a steering control mode selected when the second function of the vehicle control device 52 is selected, that is, when the vehicle is not actually driven. Specifically, the play mode is a steering control mode selected, for example, when performing simulated driving using the vehicle, or when operating a simulated vehicle using the vehicle. When the steering control mode is play mode, the reaction force control device 1A performs reaction force control, and the steering control device 1B does not perform steering control. The steering wheel 5 is operated, for example, according to the content displayed on the display device screen.

[0034] The steering wheel 5 has a steering torque T ｈSteering reaction force corresponding thereto is applied. For this reason, a user of the vehicle can feel, for example, the steering reaction force corresponding to the display content on the screen of the display device as a tactile sensation via the steering wheel 5. Not executing the steering control means, for example, forcibly limiting the current supplied to the steering motor 31 to "0 A" regardless of the steering state of the steering wheel 5. For this reason, the steered wheels 6 do not steer regardless of the steering state of the steering wheel 5. The play mode is also a mode in which the steering motor 31 is controlled so that the steered wheels 6 do not steer regardless of the operation state of the steering wheel 5.

[0035] <State Transition of Reaction Force Control Device 1A> Next, the state transition of the reaction force control device 1A will be described. The vehicle is in a stopped state.

[0036] As shown in FIG. 2, the reaction force control device 1A starts up when the vehicle power supply is turned on (step S101). Turning on or off the vehicle power supply also means, for example, turning on or off the start switch provided in the driver's seat. The start switch is operated when starting or stopping the driving source for the vehicle to travel, and is, for example, an ignition switch or a power switch.

[0037] After starting up, the reaction force control device 1A transitions in order to an initial check state (step S102), a steering angle midpoint learning process state (step S103), and a steering angle synchronization process state (step S104). The initial check, the steering angle midpoint learning process, and the steering angle synchronization process are processes in the normal mode and are a series of preparatory processes required to start executing the reaction force control for generating the steering reaction force in the reaction force motor 12.

[0038] The initial check state is a control state in which the reaction force control device 1A performs an initial check. The initial check is an initial inspection performed when the vehicle power is turned on, and includes, for example, hardware checks, CPU initialization, and initialization of variables or flags. In the initial check state, the reaction force control device 1A limits the current supplied to the reaction force motor 12 to "0A". After the completion of the initial check, the reaction force control device 1A transitions to the steering angle midpoint learning processing state (step S103).

[0039] The steering angle midpoint learning processing state is a control state in which the reaction force control device 1A executes the steering angle midpoint learning processing. The steering angle midpoint learning processing is a process of learning the steering neutral position of the steering wheel 5. The steering device 2 has, for example, a stopper mechanism. The stopper mechanism controls the steering angle θ of the steering wheel 5. ｓ This mechanism restricts the rotation of the steering wheel 5 in order to set limits. The stopper mechanism restricts the steering range of the steering wheel 5 to less than 360°, for example. The reaction force control device 1A controls the reaction force motor 12 to move the steering wheel 5 to a first operating end and then reverse it to a second operating end.

[0040] Subsequently, the reaction force control device 1A controls the rotation angle θ of the reaction force motor 12 at the start and end of the steering wheel 5's reversal operation. ａ Based on the steering angle θ ｓ Calculate the midpoint of the steering angle θ. ｓ The midpoint corresponds to the motor midpoint, which is the rotational position of the reaction force motor 12 when the steering wheel 5 is in the steering neutral position. The reaction force control device 1A controls the steering angle θ. ｓ The midpoint or motor midpoint is stored in memory as the steering neutral position of the steering wheel 5. ｓ The midpoint or motor midpoint is information regarding the steering neutral position.

[0041] However, the reaction force control device 1A learns the steering neutral position of the steering wheel 5 if the information regarding the steering neutral position stored in memory is lost. The reaction force control device 1A performs a midpoint learning process, for example, when the vehicle power is turned on for the first time after a new battery has been installed in the vehicle. This is because when the battery is removed from the vehicle during battery replacement work, the power supply to the reaction force control device 1A is cut off, causing the information regarding the steering neutral position stored in the memory of the reaction force control device 1A to be lost. By obtaining information regarding the steering neutral position through the execution of the midpoint learning process, the reaction force control device 1A determines the rotation angle θ of the reaction force motor 12. ａ Based on this, the steering angle θ is set relative to the steering neutral position. ｓ It becomes possible to calculate the steering angle θ. ｓ This is a state variable that reflects the steering state of the steering wheel 5.

[0042] When the reaction force control device 1A performs the steering angle midpoint learning process, it limits the current supplied to the reaction force motor 12 to below the rated current. The rated current is the limit of the current that the manufacturer guarantees to ensure the safe use of electrical products such as motors.

[0043] The reaction force control device 1A transitions from the rudder angle midpoint learning processing state to the rudder angle synchronization processing state when the first transition condition is met (step S104). The first transition condition is met, for example, when both of the following two conditions B1 and B2 are satisfied.

[0044] B1. The steering angle midpoint learning process is complete. That is, information regarding the steering neutral position is stored in memory. B2. The steering mode information indicates that the first function of the vehicle control device 52 has been selected. That is, the value of the steering mode information is "0". A value of "0" for the steering mode information indicates that it is requested to switch the steering control mode to normal mode.

[0045] The steering angle synchronization processing state is a control state in which the reaction force control device 1A performs steering angle synchronization processing. Steering angle synchronization processing is a normal mode process that corrects the rotational position of the steering wheel 5. When the rotational position of the steering wheel 5 is different from the rotational position corresponding to the steering position of the steering wheel 6, the reaction force control device 1A drives the reaction force motor 12 so that the rotational position of the steering wheel 5 becomes the rotational position corresponding to the steering position of the steering wheel 6. In the steering angle synchronization processing state, the reaction force control device 1A limits the current supplied to the reaction force motor 12 to the rated current or less.

[0046] When the steering angle synchronization process is completed, the reaction force control device 1A transitions to the powertrain start-up waiting state (step S105). The powertrain start-up waiting state is a control state in which the reaction force control device 1A is waiting for the powertrain start-up process to be completed. Waiting for the powertrain to start is a normal mode process. Depending on the starting state of the vehicle's powertrain, the reaction force control device 1A determines whether it is possible to transition from the powertrain start-up waiting state to the SBW (Steer-By-Wire) control state. The SBW control state is a control state in which reaction force control is executed to generate steering reaction force in the reaction force motor 12. In the powertrain start-up waiting state, the reaction force control device 1A limits the current supplied to the reaction force motor 12 to the rated current or less.

[0047] The reaction force control device 1A receives the ready flag set by the vehicle control device 52. When the ready flag is not on, the reaction force control device 1A determines that the powertrain start process is not complete and maintains the powertrain start waiting state. When the ready flag is on, the reaction force control device 1A determines that the powertrain start process is complete and transitions from the powertrain start waiting state to the SBW control state (step S106). SBW control is the normal mode of processing. In the SBW control state, the reaction force control device 1A controls the drive of the reaction force motor 12 according to the steering state of the steering wheel 5. In the SBW control state, the reaction force control device 1A limits the current supplied to the reaction force motor 12 to the rated current or less.

[0048] If the second transition condition is met in the steering angle synchronization processing state, the powertrain start waiting state, or the SBW control state, the reaction force control device 1A transitions to the stop state (step S107). The stop state is a control state in which the reaction force control device 1A stops processing related to SBW control. In the stop state, the reaction force control device 1A limits the current supplied to the reaction force motor 12 to "0A".

[0049] The second transition condition is met, for example, when any of the following three main conditions C1, C2, and C3 are satisfied: C1. An abnormality in the steering system is detected. The steering system includes a steering control device 1 and a steering device 2.

[0050] C2. The vehicle's power supply is turned off. C3. The following two subconditions C31 and C32 are all met. C31. The vehicle is stopped and the vehicle's shift range is in the parking range. The parking range is the shift range used when parking.

[0051] C32. The steering mode information indicates that the second function of the vehicle control device 52 has been selected. That is, the value of the steering mode information is "1". A value of "1" for the steering mode information indicates that it is requested to switch the steering control mode to play mode.

[0052] The reaction force control device 1A determines, for example, that the vehicle is stopped if the vehicle speed V is below a vehicle speed threshold. The vehicle speed threshold is a criterion for determining whether the vehicle is stopped or not. The reaction force control device 1A also detects the shift range, for example, using a shift position sensor installed in the vehicle.

[0053] If the main condition C3 constituting the second transition condition is met while the system is stopped, the reaction force control device 1A is restarted. If either of the main conditions C1 or C2 constituting the second transition condition is met while the system is stopped, the reaction force control device 1A is maintained in the stopped state without being restarted.

[0054] Furthermore, if the third transition condition is met in the steering angle midpoint learning processing state, the reaction force control device 1A transitions the steering control mode to play mode (step S108). The third transition condition is met when both of the following two conditions D1 and D2 are satisfied.

[0055] D1. The steering angle midpoint learning process is completed. That is, information regarding the steering neutral position is stored in memory. D2. The steering mode information indicates that the second function of the vehicle control device 52 has been selected. That is, the value of the steering mode information is "1". A value of "1" for the steering mode information indicates that it is requested to switch the steering control mode to play mode.

[0056] If the steering mode information value is "1" at the start of the steering angle midpoint learning process, the reaction force control device 1A transitions the steering control mode to play mode after the completion of the steering angle midpoint learning process. If the steering mode information value is "0" at the start of the steering angle midpoint learning process, the reaction force control device 1A transitions the steering control mode to play mode if the steering mode information value switches to "1" before transitioning from the steering angle midpoint learning process to the steering angle synchronization process. When the steering control mode is play mode, the reaction force control device 1A limits the current supplied to the reaction force motor 12 to the rated current or less.

[0057] When the steering control mode is in play mode and the fourth transition condition is met, the reaction force control device 1A transitions from play mode (S108) to the rudder angle midpoint learning processing state (S103). The fourth transition condition is met when both of the following two conditions E1 and E2 are satisfied.

[0058] E1. The vehicle is stopped and the vehicle's shift range is in the parking range. The parking range is the shift range used when parking. E2. The steering mode information indicates that the first function of the vehicle control device 52 has been selected. That is, the value of the steering mode information is "0". A value of "0" for the steering mode information indicates that it is required to switch the steering control mode to the normal mode.

[0059] When the steering control mode is in play mode and the fifth transition condition is met, the reaction force control device 1A transitions from play mode to a stopped state (step S107). The stopped state is a control state in which the reaction force control device 1A has stopped processing related to play mode. The fifth transition condition is met when either of the following two conditions F1 or F2 is satisfied.

[0060] F1. An abnormality in the steering system is detected. The steering system includes steering control device 1 and steering device 2. F2. The vehicle power is turned off.

[0061] <State transitions of steering control device 1B> Next, the state transitions of the steering control device 1B will be explained. The vehicle is in a stationary state.

[0062] As shown in Figure 3, the steering control device 1B starts up when the vehicle power is turned on (step S201). After starting up, the steering control device 1B transitions in the same order as the reaction force control device 1A: initial check state (step S202), steering angle midpoint learning state (step S203), and steering angle synchronization state (step S204). The initial check, steering angle midpoint learning state, and steering angle synchronization state are a series of preparatory processes required to start the execution of steering control that generates steering force in the steering motor 31.

[0063] The initial check state is a control state in which the steering control device 1B performs an initial check. The initial check is an initial inspection performed when the vehicle power is turned on, and includes, for example, hardware checks, CPU initialization, and initialization of variables or flags. In the initial check state, the steering control device 1B limits the current supplied to the steering motor 31 to "0A". After the completion of the initial check, the steering control device 1B transitions to the steering angle midpoint learning processing state (step S203).

[0064] The steering angle midpoint learning processing state is a control state in which the steering control device 1B executes the steering angle midpoint learning processing. The steering angle midpoint learning processing is a process for learning the steering neutral position of the steering wheel 6. The steering control device 1B controls the steering motor 31 to move the steering shaft 22 to a first operating end, and then reverses its movement to a second operating end. The first operating end is the position where the first end of the steering shaft 22 abuts against the first end of the housing 23 that houses the steering shaft 22. The second operating end is the position where the second end of the steering shaft 22 abuts against the second end of the housing 23 that houses the steering shaft 22.

[0065] Subsequently, the steering control device 1B controls the rotation angle θ of the steering motor 31 at the start and end of the reversal operation of the steering shaft 22. ｂ Based on the steering angle θ ｗ Calculate the midpoint of the steering angle θ. ｗ The midpoint corresponds to the motor midpoint, which is the rotational position of the steering motor 31 when the steering wheel 6 is in the steering neutral position. The steering control device 1B controls the steering angle θ ｗ The midpoint or motor midpoint is stored in memory as the steering neutral position of the steering wheel 6. ｗ The midpoint or motor midpoint is information regarding the steering neutral position.

[0066] However, the steering control device 1B learns the steering neutral position of the steering wheel 5 if the information regarding the steering neutral position stored in memory is lost. The steering control device 1B performs a midpoint learning process, for example, when the vehicle power is turned on for the first time after a new battery has been installed in the vehicle. While the steering control device 1B is performing the midpoint learning process, it limits the current supplied to the steering motor 31 to the rated current or less, and after the midpoint learning process is completed, it limits the current supplied to the steering motor 31 to "0A". The steering control device 1B does not perform the midpoint learning process if information regarding the steering neutral position is stored in memory. That is, the steering control device 1B limits the current supplied to the steering motor 31 to "0A".

[0067] The steering control device 1B transitions from the steering angle midpoint learning processing state to the steering angle synchronization processing state if the first transition condition described above is met, that is, if both of the two conditions B1 and B2 described above are met (step S204). However, if at least one of the two conditions B1 and B2 is not met, the steering control device 1B maintains the steering angle midpoint learning processing state.

[0068] The steering angle synchronization processing state is a control state in which the steering control device 1B performs steering angle synchronization processing. As part of the steering angle synchronization processing, the steering control device 1B limits the current supplied to the steering motor 31 to "0A". Therefore, the steering wheels 6 are maintained in a non-steered state. Steering angle synchronization processing is a process that corrects the rotational position of the steering wheel 5 to the rotational position corresponding to the steering position of the steering wheels 6. When the steering angle synchronization processing by the reaction force control device 1A is completed, the steering control device 1B transitions to the powertrain start waiting state (step S205). The powertrain start waiting state is a control state in which the steering control device 1B is waiting for the powertrain start processing to be completed.

[0069] The steering control device 1B receives a ready flag set by the vehicle control device 52 from the reaction force control device 1A. When the ready flag is not on, the steering control device 1A determines that the powertrain start process is not complete and maintains the powertrain start waiting state. When the ready flag is on, the steering control device 1B determines that the powertrain start process is complete and transitions from the powertrain start waiting state to the SBW control state (step S206). In the SBW control state, the steering control device 1B controls the drive of the steering motor 31 according to the steering state of the steering wheel 5. However, in the SBW control state, the steering control device 1B limits the current supplied to the steering motor 31 to the rated current or less.

[0070] If the second transition condition is met during the steering angle synchronization processing state, the powertrain start waiting state, or the SBW control state, that is, if any of the three main conditions C1 to C3 is met, the steering control device 1B transitions to a stopped state (step S207). The stopped state is a control state in which the steering control device 1B has stopped processing related to SBW control. In the stopped state, the steering control device 1B limits the current supplied to the steering motor 31 to "0A".

[0071] If the main condition C3 constituting the second transition condition is met while the vehicle is stopped, the steering control device 1B is restarted. If either of the main conditions C1 or C2 constituting the second transition condition is met while the vehicle is stopped, the steering control device 1B is maintained in the stopped state without being restarted.

[0072] <Transition Patterns Between Normal Mode and Play Mode> Next, we will explain the transition patterns between Normal Mode and Play Mode. Examples of transition patterns include the first to third transition patterns.

[0073] <First Transition Pattern> The first transition pattern is one in which, after the reaction force control device 1A is activated, the vehicle transitions to play mode without transitioning to the SBW control state. The first transition pattern is also the pattern in which the vehicle's second function is selected by the vehicle user between the time the vehicle power is turned on and before the vehicle transitions to the steering angle synchronization processing state. When the second function is selected, the vehicle control device 52 sets the value of the steering mode information to "1". The second function is a function that performs simulations using the vehicle.

[0074] In this case, the reaction force control device 1A and the steering control device 1B operate in normal mode after startup until the steering angle midpoint learning process is completed. After this, once the steering angle midpoint learning process is completed, the third transition condition described above is met, and the reaction force control device 1A transitions from normal mode to play mode. The third transition condition includes the two conditions D1 and D2 described above. When the steering control mode is play mode, the reaction force control device 1A limits the current supplied to the reaction force motor 12 to the rated current or less.

[0075] After the steering angle midpoint learning process is completed, the steering control device 1B is maintained in the steering angle midpoint learning process state. This is because the first transition condition is not met. Specifically, of the two conditions B1 and B2 that constitute the first transition condition, one condition B1 is met, and the other condition B2 is not met. For this reason, the steering control device 1B is maintained in the steering angle midpoint learning process state. After the midpoint learning process is completed, the steering control device 1B limits the current supplied to the steering motor 31 to "0A".

[0076] Therefore, when the steering control mode transitions to play mode, the reaction force motor 12 generates a steering reaction force according to the steering state of the steering wheel 5, while the steering motor 31 does not generate a steering force regardless of the steering state of the steering wheel 5. In other words, the steering wheel 5 is subjected to a steering reaction force according to its steering state. However, the steering wheels 6 are not steered regardless of the steering state of the steering wheel 5.

[0077] <Second Transition Pattern> The second transition pattern is a pattern in which the reaction force control device 1A transitions from the steering angle synchronization processing state, the powertrain start waiting state, or the SBW control state to the play mode. The second transition pattern is also a pattern in which the vehicle user selects a second function of the vehicle while in the steering angle synchronization processing state, the powertrain start waiting state, or the SBW control state. The second function is a function that performs a simulation using the vehicle. When the second function is selected, the vehicle control device 52 sets the value of the steering mode information to "1".

[0078] When the reaction force control device 1A is in the steering angle synchronization processing state, the powertrain start waiting state, or the SBW control state, and the vehicle is stopped and the vehicle's shift range is in the parking range, the second transition condition described above is met. Specifically, the main condition C3 that constitutes the second transition condition is met. For this reason, the reaction force control device 1A and the steering control device 1B stop processing related to SBW control. However, if the main condition C3 is met, the reaction force control device 1A and the steering control device 1B restart.

[0079] Since the vehicle's power is not turned off, the steering mode information value is maintained as "1". "1" indicates that the second function of the vehicle control device 52 has been selected. Information regarding the steering neutral position and steering neutral position is also stored in memory. Because the third transition condition described above is met, the reaction force control device 1A, after restarting, goes through the initial check state and the steering angle midpoint learning processing state before transitioning to play mode. The steering control device 1B does not satisfy the first transition condition described above, specifically condition B2 which constitutes the first transition condition, and therefore maintains the steering angle midpoint learning processing state.

[0080] <Third Transition Pattern> The third transition pattern is a pattern in which the vehicle transitions from play mode to normal mode. The third transition pattern is also a pattern in which the vehicle user selects the first function of the vehicle when the steering control mode has transitioned to play mode. When the first function is selected, the vehicle control device 52 sets the value of the steering mode information to "0". The first function is a function that controls the actual driving of the vehicle.

[0081] If the steering control mode is play mode, and the vehicle is stopped and the vehicle's shift range is in the parking range, then the fourth transition condition described above is met. Specifically, both conditions E1 and E2 that constitute the fourth transition condition are met. Therefore, the reaction force control device 1A transitions from play mode to normal mode. Specifically, the reaction force control device 1A transitions to the steering angle midpoint learning processing state (S103).

[0082] Since the vehicle's power is not turned off, the memory is maintained with information regarding the steering neutral position and information regarding the steering neutral position stored. Because the first transition condition described above is met, the reaction force control device 1A transitions to the SBW control state (S106) via the steering angle synchronization processing state (S104) and the powertrain start state (S105). Also, because the first transition condition described above is met, the steering control device 1B transitions to the SBW control state (S206) via the steering angle synchronization processing state (S204) and the powertrain start state (S205).

[0083] <Effects of the First Embodiment> The first embodiment provides the following effects: (1-1) The reaction force control device 1A can select between a normal mode and a play mode as the steering control mode. When the vehicle power is turned on, the reaction force control device 1A performs a preparatory process, which includes a midpoint learning process to learn the steering neutral position of the steering wheel 5, as part of the processing for the normal mode. The transition condition from the normal mode to the play mode includes the completion of the steering midpoint learning process. This transition condition corresponds to condition D1 which constitutes the third transition condition.

[0084] With this configuration, when the steering control mode transitions from normal mode to play mode, it transitions to play mode via a steering angle midpoint learning processing state (S103). That is, it transitions to play mode with information regarding the steering neutral position of the steering wheel 5 stored in memory. Therefore, the steering control mode can be transitioned from normal mode to play mode in an appropriate state where the learning of the steering neutral position of the steering wheel 5 is complete. Consequently, depending on the steering state of the steering wheel 5, for example, simulated driving using a vehicle or driving of a simulated vehicle can be appropriately controlled.

[0085] (1-2) The reaction force control device 1A selects a steering control mode based on a command from the vehicle control device 52 mounted on the vehicle. The command is, for example, steering mode information. The transition conditions from normal mode to play mode further include that the command requests the selection of play mode as the steering control mode, and that the vehicle is stopped. These transition conditions correspond to the two subconditions C31 and C32 that constitute the main condition C3 of the second transition condition.

[0086] This configuration prevents the steering control mode from transitioning from normal mode to play mode while the vehicle is in motion. When the steering control mode is in normal mode, if the second transition condition is met, the steering control mode transitions to play mode. This transition to play mode occurs when the vehicle is stationary, making it safe.

[0087] (1-3) The reaction force control device 1A selects a steering control mode based on a command from the vehicle control device 52 mounted on the vehicle. The command is, for example, steering mode information. The transition conditions from play mode to normal mode include the command requesting the selection of normal mode as the steering control mode and the vehicle being stopped. These transition conditions correspond to the two conditions E1 and E2 that constitute the fourth transition condition.

[0088] This configuration prevents the steering control mode from transitioning from play mode to normal mode while the vehicle is in motion. When the steering control mode is in play mode, if the fourth transition condition is met, the steering control mode transitions to normal mode. This transition to normal mode occurs when the vehicle is stationary, ensuring safety.

[0089] (1-4) When the conditions for transitioning from play mode to normal mode are met, the reaction force control device 1A transitions from play mode to midpoint learning processing. With this configuration, the reaction force motor 12 can be controlled in an appropriate state where the learning of the steering neutral position of the steering wheel 5 is complete. Therefore, the vehicle can be operated appropriately according to the steering state of the steering wheel 5.

[0090] (1-5) The reaction force control device 1A determines that the vehicle is stopped if the vehicle speed V is below the vehicle speed threshold. With this configuration, it is possible to appropriately determine whether the vehicle is stopped based on the vehicle speed V.

[0091] (1-6) When the steering control mode is in play mode, if the fifth transition conditions (F1, F2) are met, the reaction force control device 1A stops processing. Processing includes processing related to play mode. The fifth transition conditions include the detection of an abnormality in the steering system (F1) and the turning off of the vehicle power supply (F2). Therefore, if an abnormality in the steering system is detected or the vehicle power supply is turned off, the reaction force control device 1A can seamlessly stop processing.

[0092] (1-7) Play mode is separated as a different mode from normal mode. That is, the functionality of play mode can be implemented as an add-on to the existing software executed by the reaction force control device 1A. An add-on is a program that adds new functionality to the software.

[0093] <Second Embodiment> Next, a steering control device according to a second embodiment will be described. This embodiment basically has the same configuration as the first embodiment shown in Figures 1 to 3 above. Therefore, the same reference numerals are used for the same components and components as in the first embodiment, and their detailed descriptions are omitted. In this embodiment, the path for transitioning from the SBW state to the play mode, which is part of the processing in the normal mode, differs from that of the first embodiment. In addition, this embodiment differs from the first embodiment in that the fourth transition conditions (E1, E2) for transitioning from the play mode to the normal mode are omitted.

[0094] As shown in Figure 4, in the SBW control state (S106), the reaction force control device 1A transitions to the stopped state when either of the two main conditions C1 and C2 that constitute the second transition condition is met, and does not transition to the stopped state when the remaining main condition C3 is met. In other words, in this embodiment, the second transition condition when the state of the reaction force control device 1A is the SBW control state includes only the two main conditions C1 and C2, and is met when either of the two main conditions C1 or C2 is satisfied.

[0095] When the sixth transition condition is met in the SBW control state, the reaction force control device 1A transitions to the steering angle midpoint learning state (S103) via the steering angle asynchronous processing state (S109). The steering angle asynchronous processing state is a control state in which steering angle synchronous processing, which corrects the rotational position of the steering wheel 5, is not performed. In the steering angle asynchronous processing state, the reaction force control device 1A limits the current supplied to the reaction force motor 12 to the rated current or less.

[0096] The sixth transition condition is the same as the main condition C3 that constitutes the second transition condition, and is met when the following two conditions G1 and G2 are all satisfied. G1. The vehicle is stopped and the vehicle's shift range is in the parking range.

[0097] G2. The steering mode information indicates that the second function of the vehicle control device 52 has been selected. That is, the value of the steering mode information is "1". A value of "1" for the steering mode information indicates that it is required to switch the steering control mode to play mode.

[0098] When the sixth transition condition is met, the vehicle's power remains on, and therefore the steering mode information value is held at "1". Information regarding the steering neutral position and steering neutral position is also stored in memory. Since the third transition condition is met, the reaction force control device transitions the steering control mode to play mode (S108).

[0099] As shown in Figure 5, in the SBW control state (S206), the steering control device 1B transitions to the stopped state when either of the two main conditions C1 and C2 that constitute the second transition condition is met, and does not transition to the stopped state when the remaining main condition C3 is met. In other words, in this embodiment, the second transition condition when the state of the steering control device 1B is the SBW control state includes only the two main conditions C1 and C2 mentioned above, and is met when either of the two main conditions C1 or C2 is satisfied.

[0100] When the sixth transition condition is met in the SBW control state, the steering control device 1A transitions to the steering angle midpoint learning processing state via the steering angle asynchronous processing state (S208) (S203). The steering angle asynchronous processing state is a control state in which steering angle synchronous processing, which corrects the rotational position of the steering wheel 5, is not performed. In the steering angle asynchronous processing state, the steering control device 1B limits the current supplied to the steering motor 31 to "0A". Since the first transition condition is not met, the steering control device is maintained in the steering angle midpoint learning processing state.

[0101] <Effects of the Second Embodiment> The second embodiment provides the following effects: (2-1) The completion of the midpoint learning process is the first condition. The first condition corresponds to condition D1 which constitutes the third transition condition. The command requests the selection of play mode as the steering control mode, which is the second condition. The command is, for example, steering mode information. The second condition corresponds to sub-condition D32 which constitutes the main condition C3 of the second transition condition. The vehicle being stopped is the third condition. The third condition corresponds to sub-condition D31 which constitutes the main condition C3 of the second transition condition.

[0102] When the steering control mode is in normal mode, the reaction force control device 1A switches from reaction force control to midpoint learning processing when the second and third conditions are met during the execution of reaction force control to generate a reaction force in the reaction force motor 12. Subsequently, when the first and second conditions are met, the reaction force control device 1A transitions to play mode.

[0103] With this configuration, processing transitions from reaction force control to midpoint learning processing, and then the steering control mode transitions from normal mode to play mode. Therefore, when the steering neutral position of the steering wheel 5 has been learned, the steering control mode can be transitioned from the execution state of reaction force control, which is part of the normal mode processing, to play mode.

[0104] (2-2) When the sixth transition conditions (G1, G2) are met in the SBW control state (S106), the steering control mode transitions to play mode (S108) via the rudder angle asynchronous processing state (S109) and the rudder angle midpoint learning processing state (S103). Therefore, compared to the configuration in the first embodiment where the steering control mode is transitioned to play mode by restarting the reaction force control device 1A when the main condition C3 constituting the second transition condition is met in the SBW control state, the steering control mode can be transitioned from normal mode to play mode more quickly.

[0105] (2-3) When the steering control state is in play mode, if the fifth transition conditions (F1, F2) are met, the reaction force control device 1A transitions to a stopped state. The fifth transition conditions include the vehicle power being turned off (F2). Therefore, when the vehicle power is turned off, the steering control mode transitions from play mode to a stopped state. To transition the steering control mode from play mode to normal mode, the vehicle power must be turned on again. If the first transition conditions (B1, B2) are met between the time the reaction force control device 1A is started and the transition to the steering angle synchronization processing state, the steering control mode transitions to normal mode. Therefore, it is possible to suppress the steering control mode from unintentionally transitioning from play mode to normal mode.

[0106] <Third Embodiment> Next, a steering control device according to the third embodiment will be described. This embodiment integrates the first and second embodiments and basically has the same configuration as the second embodiment shown in Figures 4 and 5. Therefore, the same reference numerals are used for the same components and components as in the second embodiment, and their detailed descriptions are omitted. This embodiment differs from the second embodiment in that a fourth transition condition (E1, E2) is set for transitioning from play mode to normal mode.

[0107] As shown in Figure 6, when the steering control mode is in play mode and the fourth transition condition is met, the reaction force control device 1A transitions from play mode (S108) to the rudder angle midpoint learning processing state (S103). The rudder angle midpoint learning processing state is part of the processing in normal mode. The fourth transition condition is met when all of the previous two conditions E1 and E2 are satisfied.

[0108] Since the vehicle's power is not turned off, the memory is maintained with information regarding the steering neutral position and information regarding the steering neutral position stored. Also, the value of the steering mode information is maintained at "0". Since all of the above two conditions B1 and B2 are met, the first transition condition is satisfied. Therefore, the reaction force control device 1A transitions to the SBW control state (S106) via the steering angle synchronization processing state (S104) and the powertrain start state (S105).

[0109] As shown in Figure 7, since the first transition condition is met, the steering control device 1B transitions to the SBW control state (S206) via the steering angle synchronization processing state (S204) and the powertrain start state (S205). The steering control device 1B basically performs the same processing as in the second embodiment described above.

[0110] <Effects of the Third Embodiment> The third embodiment provides the following effects. (3-1) The steering control device 1 combines the configuration of the first embodiment and the configuration of the second embodiment. Therefore, it can provide the effects described in columns (1-1) to (1-7) of the first embodiment and the effects described in columns (2-1) to (2-3) of the second embodiment.

[0111] <Other Embodiments> The first to third embodiments may be implemented with the following modifications: The third transition condition may include a third condition D3 in addition to the two conditions D1 and D2 mentioned above. Condition D3 is, for example, that the vehicle is stopped.

[0112] - The sub-condition C31 constituting the second transition condition and the condition E1 constituting the fourth transition condition may be either the vehicle being stopped or the vehicle's shift range being the parking range. The vehicle's shift range being the parking range indicates that the vehicle is stopped.

[0113] - In the steering angle synchronization processing state, powertrain start waiting state, or SBW control state, if the main condition C3 constituting the second transition condition is met, the reaction force control device 1A and the steering control device 1B may be prevented from restarting. For example, in the steering angle synchronization processing state, powertrain start waiting state, or SBW control state, if the main condition C3 constituting the second transition condition is met, the reaction force control device 1A may transition to the initial check state (S102) or the steering angle midpoint learning state (S103). The same applies to the steering control device 1B as to the reaction force control device 1A.

[0114] - The reaction force control device 1A and the steering control device 1B may generate an electrical signal indicating an abnormality in the steering system when an abnormality is detected, and transmit the generated electrical signal to the vehicle control device 52. The vehicle control device 52 may perform a specific process when it receives an electrical signal indicating an abnormality in the steering system from at least one of the reaction force control device 1A and the steering control device 1B. The specific process may include, for example, a process to limit the vehicle speed or a process to fix the vehicle's shift range. If the vehicle is equipped with an autonomous driving system, the specific process may be a process to move the vehicle to, for example, the shoulder of the road. The vehicle control device 52 moves the vehicle to, for example, the shoulder of the road by controlling the steering mechanism 4. An autonomous driving system is a vehicle system that realizes an autonomous driving function in which the system takes over the driving of the vehicle.

[0115] - When the vehicle has a wireless communication function and the second function of the vehicle control device 52 is selected, the steering device 2 may be used as follows: The steering device 2 is used for recreational purposes to remotely control a radio-controlled device via wireless communication with the radio-controlled device. The radio-controlled device is a simulated vehicle, including, for example, a radio-controlled car and a drone. The radio-controlled device may be equipped with a camera. Video data captured by the camera is transmitted wirelessly to the vehicle. The vehicle control device 52 displays the received video data on a display device. The vehicle user operates the steering wheel, accelerator pedal, and brake pedal while looking at the screen of the display device.

[0116] - By taking advantage of the fact that the steering mechanism 3 and the steering control mechanism 4 are not mechanically connected, various controls other than the steering wheel can be used. For example, a joystick could be used as a control.

[0117] The steering device 2 may have a clutch. In this case, the steering shaft 11 and the pinion shaft 21 are connected via a clutch. The clutch is, for example, an electromagnetic clutch that intermittently controls power by intermittently energizing the excitation coil. The steering control device 1 performs intermittent control to switch the clutch on and off. When the clutch is disengaged, the power transmission between the steering wheel 5 and the steering wheels 6 is mechanically disconnected. When the clutch is engaged, the power transmission between the steering wheel 5 and the steering wheels 6 is mechanically reconnected.

[0118] The reaction force control device 1A and the reaction force motor 12 may be integrated to form a so-called electromechanically integrated reaction force actuator. Similarly, the steering control device 50 and the steering motor 31 may be integrated to form a so-called electromechanically integrated steering actuator.

[0119] In this specification, "at least one of A and B" means "A only, B only, or both A and B."

Claims

1. A steering control device comprising: a reaction force control device configured to control a reaction force motor that generates a reaction force applied to a vehicle's control element; and a steering control device configured to control a steering motor that generates a steering force applied to a steering shaft from which power transmission is separated, wherein the reaction force control device is configured to allow selection of a normal mode and a play mode as steering control modes, the normal mode being selected when the vehicle is actually driven, the play mode being selected when the vehicle is used for simulated driving or when the vehicle is used for operating a simulated vehicle, the reaction force control device being configured to perform a preparation process, including a midpoint learning process for learning the neutral position of the control element, as part of the processing of the normal mode when the vehicle power is turned on, and the transition condition from the normal mode to the play mode being the completion of the midpoint learning process.

2. The steering control device according to claim 1, wherein the reaction force control device is configured to select the steering control mode based on a command from a vehicle control device mounted on the vehicle, and the transition condition from the normal mode to the play mode further includes: the command requests the selection of the play mode as the steering control mode, and the vehicle is stopped.

3. The steering control device according to claim 2, wherein the first condition is that the midpoint learning process is completed, the second condition is that the command requires the selection of the play mode as the steering control mode, the third condition is that the vehicle is stopped, and the reaction force control device is configured to transition from the reaction force control to the midpoint learning process when the second and third conditions are met during the execution of reaction force control to generate a reaction force in the reaction force motor when the steering control mode is the normal mode, and then transition to the play mode when the first and second conditions are met thereafter.

4. The steering control device according to claim 1, wherein the reaction force control device is configured to select the steering control mode based on a command from a vehicle control device mounted on the vehicle, and the transition condition from the play mode to the normal mode is that the command requests the selection of the normal mode as the steering control mode, and the vehicle is stopped.

5. The steering control device according to claim 4, wherein the reaction force control device is configured to transition from the play mode to the midpoint learning process when the transition condition from the play mode to the normal mode is met.

6. The steering control device according to any one of claims 2 to 5, wherein the reaction force control device is configured to determine that the vehicle is stopped when the vehicle speed is below a vehicle speed threshold.

Images