Steering system

Abstract

To provide a steering system that can execute control suitable for the case where an operation member is used in a game.SOLUTION: The steering system is a steer-by-wire type steering system that comprises an operation device 2 including an operation member 20 and a reaction force applying device 25 that applies operation reaction force to the operation member 20, a turning device 3 that turns wheels in accordance with supplied currents for turning, and a controller 4 that controls the turning device 3 and the reaction force applying device 25, on the basis of an operation signal relating to movement of the operation member 20 received from the operation device 2, which is configured to be switchable between a normal mode in which wheels 11 and 12 are turned based on the operation signal and a virtual mode in which a virtual moving body 8a created as a video is steered based on the operation signal. The controller 4 is configured to set the currents for turning to current values at which the wheels 11 and 12 are not turned without depending on the operation signal, in the virtual mode.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a steering system.

Background Art

[0002] Recently, in a steer-by-wire type steering system in which an operation member and a steering device are mechanically separated, a steering system has been developed that is configured to allow a user to play a game using the operation member, for example, while the electric vehicle is charging. For example, Japanese Patent Application Laid-Open No. 2022-1925 discloses a vehicle that can switch an operation target by an operation unit of a steering device between a vehicle and a virtual moving body in a game. That is, such a steering system is configured to be able to switch between a normal mode in which the vehicle is an operation target and a game mode in which a virtual moving body is an operation target.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a steer-by-wire type steering system, when an operation member is operated by a user, a reaction force applying device is configured to apply an operation reaction force to the operation member according to the operation of the operation member. However, since the vehicle is not actually running in the game mode, if the same control as the normal mode is applied to the game mode, control that is not suitable for the situation may be performed.

[0005] An object of the present invention is to provide a steering system capable of executing control suitable for using an operation member in a game.

Means for Solving the Problems

[0006] A steering system of the present invention includes an operation device including an operation member for a user to operate the steering wheel and a reaction force applying device that applies an operation reaction force to the operation member, a steering device that is mechanically separated from the operation device and steers wheels in response to a steering current supplied thereto, and a controller that controls the steering device and the reaction force applying device based on an operation signal related to the movement of the operation member received from the operation device. The steering system is a steer-by-wire steering system that is switchable between a normal mode in which the wheels are steered based on the operation signal and a virtual mode in which a virtual moving object created as a video is steered based on the operation signal. In the virtual mode, the controller is configured to set the steering current to a current value that does not cause the wheels to turn regardless of the operation signal. [Effects of the Invention]

[0007] According to the present invention, in the virtual mode, the steering current supplied to the steering device is set to a current value (e.g., 0) at which the wheels do not turn. This prevents unnecessary steering of the wheels due to the operation of the operating member, thereby reducing tire deterioration and power consumption. In other words, according to the present invention, it is possible to execute control suitable for use of the operating member in a game. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a configuration diagram of a steering system according to an embodiment of the present invention; [Figure 2] 3A and 3B are conceptual diagrams for explaining steering control and reaction force control according to the present embodiment. [Figure 3] FIG. 4 is a conceptual diagram for explaining reaction force control according to the present embodiment. [Figure 4] 10A and 10B are conceptual diagrams for explaining the difference in operation reaction force when the vehicle is moving and when the vehicle is stopped in this embodiment. [Figure 5] 4 is a flowchart showing a flow of changing a control mode according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] A steering system 1 according to one embodiment of the present invention will be described in detail below with reference to the drawings. In addition to the following examples, the present invention can be implemented in various forms with various modifications and improvements based on the knowledge of those skilled in the art. As an example, the steering system 1 according to this embodiment is mounted on an electric vehicle. In-vehicle communication is performed using, for example, CAN (car area network or controllable area network), FlexRay, Ethernet, or the like.

[0010] 1, the steering system 1 includes an operation device 2, a steering device 3, and a controller 4. The operation device 2 of this embodiment includes an operation member 20, a steering shaft 21, a steering column 22, an operation amount sensor 23, an operation torque sensor 24, and a reaction force imparting device 25.

[0011] The operating member 20 is a handle member for steering operation by the user. The operating member 20 is, for example, a steering wheel. The shape of the operating member 20 is not limited to a circular shape like a steering wheel, but may be a polygonal shape such as a square shape. The operating member 20 can also be called a steering operating member. The operating member 20 is fixed to the tip of a steering shaft 21. The operating member 20 and the steering shaft 21 are rotatably held to an instrument panel reinforcement by a steering column 22.

[0012] The operation amount sensor 23 is a sensor that detects the operation amount (operation angle) of the operation member 20. The operation torque sensor 24 is a sensor that detects the operation torque of the operation member 20. The operation torque can also be said to be the operation force applied to the operation member 20 by the user. The operation torque sensor 24 detects the amount of twist of a torsion bar 27 incorporated in the steering shaft 21, for example.

[0013] The reaction force applying device 25 is a device that applies an operating reaction force to the operating member 20. The reaction force applying device 25 includes a reaction force motor 26 which is an electric motor. The reaction force applying device 25 uses the reaction force motor 26 supported by the steering column 22 as a power source, and applies an operating reaction force for steering operation to the operating member 20 via the steering shaft 21. The reaction force applying device 25 has a general structure including a speed reducer and the like. A rotation angle sensor 26a is provided on the reaction force motor 26.

[0014] The steering device 3 is a device that steers the wheels 11, 12 (front wheels or steered wheels). The steering device 3 is mechanically separated from the operating device 2. The steering device 3 includes a steering motor 35 which is an electric motor as a drive source, and a current sensor 351 that detects the current value of the steering current input to the steering motor 35. More specifically, the steering device 3 includes a steering rod 31, a housing 32, a rod moving mechanism 33, a steering motor 35, a current sensor 351, a rotation angle sensor 352, and a steering angle sensor 36.

[0015] The steering rod 31 is a member whose both ends are respectively connected to the left and right steering knuckles 90 via tie rods 34. The housing 32 is a member that supports the steering rod 31 so as to be movable left and right and is fixedly held by the vehicle body.

[0016] The rod moving mechanism 33 is a mechanism for moving the steering rod 31 left and right using the steering motor 35 as a drive source. The steering motor 35 is an electric motor that steers the wheels 11, 12. The rod moving mechanism 33 mainly consists of a ball screw mechanism composed of a ball groove screwed onto the steering rod 31 and a nut that engages with the ball groove via bearing balls and is rotated by the steering motor 35. Since it has a general structure, a detailed description of the rod moving mechanism 33 will be omitted.

[0017] The current sensor 351 is a sensor that detects the current value of the control current (i.e., the steering current) input to the steering motor 35. The rotation angle sensor 352 is a sensor that detects the rotation angle of the steering motor 35. The steering angle sensor 36 is a sensor that detects the steering angle (steering amount) of the wheels 11 and 12. The steering angle sensor 36 detects the amount of movement of the steering rod 31 to the left and right from the neutral position.

[0018] The controller 4 is configured to control the steering device 3 and the reaction force applying device 25 based on the operation signal regarding the operation of the operation member 20 received from the operation device 2. The controller 4 is configured to receive a steering angle signal regarding the steering angle of the wheels 11 and 12 from the steering device 3, that is, the detection value of the steering angle sensor 36. It can be said that the controller 4 controls the steering device 3 and the reaction force applying device 25 based on the operation signal and the steering angle signal.

[0019] The controller 4 is a computer including one or more processors 41 and one or more memories 42. The computer can also be referred to as an electronic control unit (ECU). The controller 4 is communicably connected to the operation device 2 and the steering device 3. The operation device 2 and the steering device 3 are electrically connected via the controller. That is, the steering system 1 is a steer-by-wire type steering system that converts the mechanical operation of the operation member 20 by the user into an electrical signal and transmits the electrical signal to the steering device 3 mechanically separated from the operation member 20 to steer the vehicle. Note that the controller 4 may be composed of two or more communicably connected computers. For example, the controller 4 may be composed of the controller (computer) of the operation device 2 and the controller (computer) of the steering device 3.

[0020] (Control Mode) The steering system 1 is configured to be switchable between a normal mode in which the wheels 11, 12 are steered based on an operation signal and a virtual mode in which a virtual moving object 8a created as an image is steered based on the operation signal. In other words, the steering system 1 has at least two control modes set therein. The normal mode is a control mode for steering a vehicle based on the operation of the operation member 20. The virtual mode is a control mode in which, for example, a virtual moving object 8a (e.g., an image of a vehicle) represented as an image in a game is operated with the operation member 20. The virtual moving object 8a is created as an image that can be viewed inside the vehicle. The normal mode can also be referred to as, for example, a first mode, a main mode, or a real mode. The virtual mode can also be referred to as, for example, a second mode, a sub mode, or a game mode.

[0021] A display device 80 is disposed inside the vehicle. Examples of the display device 80 include an instrument panel display, a navigation system display, a windshield onto which images and the like are projected, a mobile device display, AR glasses, or a head-mounted display. The game console 8 may be disposed inside the vehicle, or may be disposed outside the vehicle by being connected to the vehicle via wireless communication. The game console 8 can be considered a computer equipped with one or more processors and one or more memories. The game console 8 and the controller 4 are connected so that only predetermined information can be communicated.

[0022] In the virtual mode, the game machine 8 displays a virtual moving object 8a on the display device 80. The controller 4 and / or the CAN transmits an operation signal or the like (for example, operation information that can be read from the operation signal) to the game machine 8. The game machine 8 creates a display image of the virtual moving object 8a on the display device 80 based on information received from the vehicle side (for example, the CAN), and displays on the display device 80 a situation in which the virtual moving object 8a is being steered. That is, in the virtual mode, the user can steer the virtual moving object 8a displayed on the display device 80 by operating the operation member 20.

[0023] Based on the user's operation (instruction), the controller 4 switches between the normal mode and the virtual mode. For example, when the user performs a button operation to select the virtual mode on the mode selection means (such as an operation panel) provided on the vehicle, the controller 4 checks that the predetermined conditions are satisfied and then switches the control mode of the vehicle from the normal mode to the virtual mode. Similarly, the controller 4 switches the control mode from the virtual mode to the normal mode based on the operation of the operation panel or the like by the user. When the user selects the virtual mode and the predetermined conditions are satisfied, the controller 4 turns on the change permission flag. When the user does not select the virtual mode or the predetermined conditions are not satisfied, the change permission flag remains off. The virtual mode is a control mode assumed for the user to play a game using the operation member 20 when the vehicle is in a stopped state, such as during charging of the battery of an electric vehicle.

[0024] (Details of the normal mode) In the normal mode, the controller 4 controls the steering motor 35 based on the detected value of the operation amount sensor 23 (the operation amount or operation angle of the operation member 20). The controller 4 calculates the target steering angle from the detected value of the operation amount sensor 23 and sets the current value of the steering current based on the difference between the target steering angle and the actual steering angle (the detected value of the steering angle sensor 36). The controller 4 supplies the set steering current to the steering motor 35.

[0025] In the normal mode, the controller 4 sets the operation reaction force on the operation member 20 based on the detected values of the operation amount sensor 23 and the operation torque sensor 24, and controls the reaction force motor 26. The controller 4 supplies a control current (hereinafter also referred to as the reaction force current) corresponding to the set operation reaction force to the reaction force motor 26. In the normal mode, the controller 4 sets the operation reaction force of the operation member 20 so as to simulate, for example, a power steering type steering system (hereinafter also referred to as a mechanically connected system) in which the operation member 20 and the steering device 3 are mechanically connected.

[0026] To explain an example of the calculation by the controller 4, as shown in FIG. 2, in the steering control, the deviation term P is calculated by multiplying the angle difference, which is the difference between the target steering angle St and the actual steering angle Sa, by a predetermined deviation term gain Gp. Also, the speed term D is calculated by multiplying the speed difference, which is the difference between the target steering angular velocity Vt, which is the value obtained by differentiating the target steering angle St with respect to time, and the actual steering angular velocity Va, which is the value obtained by differentiating the actual steering angle Sa with respect to time, by a predetermined speed term gain Gd. Further, the damping term M is calculated by multiplying the above speed difference by a damping term gain Gm.

[0027] The damping term M is subtracted from the sum of the deviation term P and the speed term D, and the steering torque command value Ts is calculated. The deviation term P is a calculation term that increases the steering torque as the angle difference increases. The speed term D is a calculation term that increases the steering torque as the speed difference increases. The damping term M is a calculation term for suppressing sudden changes in the steering torque. The steering torque command value Ts is converted into a steering current command value by current feedback control, and the steering current Is corresponding to the steering current command value is supplied to the steering motor 35.

[0028] In the above calculation, as the calculation terms, other calculation terms (such as an integral term) used in known feedback control may be used. The speed term D can also be said to be a differential term. The deviation term P corresponds to the first term, the speed term D corresponds to the second term, and the damping term M corresponds to the third term. The deviation term gain Gp corresponds to the first gain, the speed term gain Gd corresponds to the second gain, and the damping term gain Gm corresponds to the third gain.

[0029] In reaction force control, a compensation torque value Tc set based on an angular difference is added to a reaction force control amount set based on a detected value of an operation amount sensor 23 or the like, and a reaction force torque command value Tr is calculated. The compensation torque value Tc is set to increase as the angular difference increases. The control for setting the compensation torque value Tc is referred to as deviation compensation control CD. The compensation torque value Tc is set to inform the user of the magnitude of the angular difference, that is, the follow-up deficiency of the steering motor 35 with respect to the target steering angle. The compensation torque value Tc is set from the viewpoints of providing information to the user and suppressing operation. The reaction force control amount will be described later. The reaction force torque command value Tr is converted into a reaction force current command value by current feedback control FB, and a reaction force current Ir corresponding to the reaction force current command value is supplied to the reaction force motor 26.

[0030] To explain an example of the calculation of the reaction force control amount, the reaction force control amount is a value including a separately calculated virtual axial force value Fv. The virtual axial force value Fv is calculated based on, for example, a current axial force value Fi and an angular axial force value Fa as shown in FIG. 3. The current axial force value Fi is an operation reaction force set based on the change in the steering current. For example, when the vehicle travels on an uneven road surface, a change in the actual steering angle Sa may cause an angular difference, and a change may appear in the steering current. This is because the steering load changes according to the road surface conditions. The current axial force value Fi is set (calculated) in response to such a change in the steering current in order to inform the user of the road surface conditions. By changing the operation reaction force in response to the change in the steering current, the user can grasp the road surface conditions. The current axial force value Fi can be said to be a component of feedback control, and the angular axial force value Fa can be said to be a component of feedforward control.

[0031] The angular axial force value Fa is calculated by the sum of the first axial force value Fa1 and the second axial force value Fa2. The first axial force value Fa1 is calculated by multiplying the vehicle speed gain Gs set according to the vehicle speed and the target steering angle St. The vehicle speed gain Gs is set to increase as the vehicle speed increases. The first axial force value Fa1 increases as the vehicle speed increases and also increases as the target steering angle St increases. The first axial force value Fa1 can be said to represent, for example, a force that simulates the self-aligning torque felt by a user who operates an operating member in a mechanically connected system.

[0032] The first axial force value Fa1 is calculated based on the vehicle speed and the target steering angle St. The first axial force value Fa1 can be said to be a value corresponding to the operating reaction force when the vehicle speed is higher than a predetermined speed (predetermined speed ≥ 0). The first axial force value Fa1 can also be said to be a value representing the operating reaction force during vehicle travel. The second axial force value Fa2 is a value for expressing the angular hysteresis in the stopped state. The second axial force value Fa2 can be said to be a value corresponding to the operating reaction force when the vehicle speed is below a predetermined speed (predetermined speed ≥ 0). The second axial force value Fa2 can also be said to be a value representing the operating reaction force in a very low-speed driving state or a stopped state. The second axial force value Fa2 can also be said to be a value for calculating the operating reaction force peculiar to stopping.

[0033] When the vehicle with a mechanically connected system is in a stopped state and the user operates the operating member 2, due to the frictional force between the tire and the road surface, a relatively large operating force is required at the initial stage of operating the operating member 20. Also, in this state, the operating member 20 once operated is difficult to return to the central position due to the frictional force. The second axial force value Fa2 is a value for simulating such a phenomenon at the time of stopping in a mechanically connected system with the operating reaction force. As shown in FIG. 4, in the normal mode, in order to simulate a mechanically connected system, the reaction force control is designed such that the relationship between the operating reaction force and the operating angle of the operating member 20 is different between when the vehicle is stopped (when parked) and when the vehicle is traveling. The second axial force value Fa2 may be calculated, for example, when the vehicle speed is below a predetermined speed.

[0034] The virtual axial force value Fv is calculated by mixing the current axial force value Fi and the angle axial force value Fa, as shown in the following equation (1). This mixing ratio R is calculated, for example, based on the vehicle speed and the actual steering angle Sa (0≦R≦1). The vehicle speed is calculated, for example, based on the detection value of a wheel speed sensor provided on each wheel. Fv=Fi×R+Fa×(1-R) ·····(1) The mixing ratio R is set, for example, so that the ratio of the current axial force value Fi in the virtual axial force value Fv increases as the calculation value Cr, which is calculated (or set) based on the vehicle speed and the actual steering angle Sa, increases. The mixing ratio R corresponds to a first ratio, and the ratio (1-R) corresponds to a second ratio. The sum of the first ratio and the second ratio is 1. In this way, the virtual axial force value Fv is a value obtained by mixing the current axial force value Fi and the angle axial force value Fa based on the mixing ratio R corresponding to the calculation value Cr. It can also be said that the virtual axial force value Fv is calculated based on the vehicle speed, the detection value of the steering angle sensor 36, the detection value of the operation amount sensor 23, and the detection value of the current sensor 351. The reaction force current Ir is set based on the sum of the reaction force control amount including the virtual axial force value Fv and the compensation torque value Tc.

[0035] (Virtual mode details) In the virtual mode, controller 4 sets the steering current to a current value at which wheels 11, 12 do not turn, regardless of the operation signal (regardless of the operation of operation member 20). It can also be said that controller 4 sets the absolute value of the steering current to a predetermined value or less. As an example, in the virtual mode, controller 4 sets the steering current to 0 regardless of the operation signal. In other words, in the virtual mode, controller 4 is configured not to supply a steering current to steering motor 35, as a general rule. As a result, steering motor 35 does not operate in response to an operation signal, and wheels 11, 12 are not steered. The current value of the steering current at which wheels 11, 12 do not turn (also referred to as the predetermined current value) can be calculated in advance by experiments, simulations, etc., assuming, for example, driving on a typical paved or unpaved road.

[0036] An example of the process of setting the steering current to a predetermined current value will be described assuming that the predetermined current value is set to 0. In the virtual mode, the controller 4 sets the steering torque command value Ts to 0 regardless of the values of the deviation term P, the speed term D, and the attenuation term M. As a result, the steering current command value also becomes 0, and the steering current Is is also set to 0 (see Figure 2). As another example, the controller 4 may set the values of the deviation term P, the speed term D, and the attenuation term M to 0 in the virtual mode. Also, as another example, the controller 4 may set the values of the deviation term gain Gp, the speed term gain Gd, and the attenuation term gain Gm to 0 in the virtual mode. Also, as another example, the controller 4 may set the steering current command value to 0 in the virtual mode. By these processes, the steering current Is can also be set to 0. When the predetermined value is a value other than 0, from the viewpoint of ease of calculation, it is preferable for the controller 4 to set the steering torque command value Ts or the steering current command value to a value corresponding to the predetermined current value.

[0037] Also, as another example, in the virtual mode, the controller 4 may set the target steering angle to a predetermined angle (constant value) regardless of the operation signal (the operation amount or operation angle of the operation member 20). According to this, each calculation term P, D, M is not output, and the steering torque command value Ts is also not output. That is, even with this configuration, the steering current Is can be set to 0. When the target steering angular velocity is not calculated based on the target steering angle, the controller 4 sets the target steering angle to a predetermined angle and sets the target steering angular velocity to 0 in the virtual mode.

[0038] When the control mode switches from the normal mode to the virtual mode and the controller 4 sets the steering torque command value Ts to 0, the controller 4 may gradually decrease the steering torque command value Ts from the value at the time of switching to 0. That is, the controller 4 may gradually decrease the steering torque command value Ts from the value in the normal mode immediately before the control mode switch to 0. As a means for gradual decrease, for example, a rate limit, that is, a temporal slope constraint, may be used, or a filter process that delays the phase of the signal may be used.

[0039] In the reaction force control of the virtual mode, the controller 4 sets the compensation torque value Tc to a predetermined torque value regardless of the angle difference. This makes it possible to control the compensation torque value Tc, which is a component that is not suitable for the virtual mode, to an appropriate value. As an example, the predetermined torque value in this embodiment is 0. In other words, in the virtual mode, the controller 4 sets the compensation torque value Tc to 0 regardless of the angle difference.

[0040] Furthermore, in the reaction force control in the virtual mode, the controller 4 sets the calculated value Cr and the second axial force value Fa2 to 0 (see FIG. 3). By setting the calculated value Cr to 0, it is possible to eliminate the component of the current axial force value Fi from the virtual axial force value Fv. The current axial force value Fi is a value that is valid when the vehicle is traveling, that is, a value for the normal mode, and therefore is unnecessary in the virtual mode as is. Eliminating this component suppresses the application of unnecessary operation reaction forces. In the virtual mode, the controller 4 may, for example, set the vehicle speed to 0 so that the calculated value Cr becomes 0.

[0041] The second axial force value Fa2 is a value for indicating the difference between the operation reaction force when the vehicle is stopped and when the vehicle is moving, as shown in FIG. 4. In virtual mode, in most cases, the operation reaction force when the vehicle is stopped is unnecessary. Therefore, when the controller 4 sets the second axial force value Fa2 to 0 in virtual mode, the angle axial force value Fa is calculated without the second axial force value Fa2. When the calculated value Cr is 0 and the second axial force value Fa2 is also 0, the virtual axial force value Fv becomes a value mainly composed of the first axial force value Fa1 (it can also be said to be a value including only the first axial force value Fa1). In other words, the steering system 1 can output an operation reaction force appropriate for the virtual mode.

[0042] In the virtual mode, the controller 4 uses a preset non-zero value (also referred to as a predetermined speed) as the vehicle speed used in the calculation of the first axial force value Fa1. The controller 4 may vary this predetermined speed according to the operation amount of the accelerator operation member 71 or the operation amount of the brake operation member 72. The controller 4 is configured to receive an accelerator signal related to the operation of the accelerator operation member 71 for accelerator operation provided in the vehicle and a brake signal related to the operation of the brake operation member 72 for brake operation provided in the vehicle. The accelerator signal corresponds to, for example, the detection value of a sensor (not shown) that detects the operation amount of the accelerator operation member 71. The brake signal corresponds to, for example, the detection value of a sensor (not shown) that detects the operation amount of the brake operation member 72.

[0043] In the virtual mode, the controller 4 may change the vehicle speed used in the calculation of the first axial force value Fa1 based on the accelerator signal and / or the brake signal. Thereby, the user's accelerator operation and / or brake operation can be reflected in the game. That is, even when the controller 4 cannot receive information regarding the speed of the virtual moving body 8a from the game machine 8, the controller 4 can set an operation reaction force corresponding to the accelerator operation or the brake operation. Note that in the virtual mode, the controller 4 may set the second axial force value Fa2 to 0 only when it is receiving the accelerator signal (0 < operation amount). The controller 4 may set the second axial force value Fa2 to the same value as in the normal mode only when it is receiving the brake signal (0 < operation amount).

[0044] In the virtual mode, when the controller 4 can receive information regarding the speed of the virtual moving body 8a from the game machine 8, it may calculate the first axial force value Fa1 and the first ratio R (calculated value Cr) based on the speed information. Further, in this configuration, when the controller 4 receives information that the speed of the virtual moving body 8a is 0, it may set the value of the second axial force value Fa2 to the same value as in the normal mode. Also, when the controller 4 can receive information regarding the lateral acceleration and yaw rate of the virtual moving body 8a from the game machine 8, it may calculate the virtual axial force value Fv based on the information.

[0045] As an example of changing the control mode, as shown in FIG. 5, the controller 4 receives a change permission flag at a predetermined timing (S11). The predetermined timing may be, for example, periodic (regular), or may be after a user performs a change operation from the normal mode to the virtual mode. When the change permission flag is on (S12: Yes), the controller 4 sets the control mode to the virtual mode and sets the steering torque command value Ts and the compensation torque value Tc to 0 (S13). At this time, the controller 4 sets the first ratio R and the second axial force value Fa2 to 0. When the change permission flag is off (S12: No), the controller 4 sets the control mode to the normal mode and sets the steering torque command value Ts and the compensation torque value Tc according to the operation signal (S14). Further, the controller 4 calculates the first ratio R and the second axial force value Fa2 in the normal mode.

[0046] According to the present embodiment, in the virtual mode, the steering current Is supplied to the steering device 3 is set to a current value (for example, 0) at which the wheels 11 and 12 do not steer. Therefore, unnecessary steering of the wheels 11 and 12 due to the operation of the operation member 20 is suppressed, and deterioration of the tires and an increase in power consumption are suppressed. That is, according to the present embodiment, it is possible to execute control suitable for using the operation member 20 in a game.

[0047] In a situation where the wheels 11 and 12 are not steered, the compensation torque value Tc for informing the user of insufficient follow-up to the target steering angle becomes unnecessary. According to the present embodiment, the compensation torque value Tc included in the operation reaction force in the normal mode is set to 0 in the virtual mode. Thereby, unnecessary components in the virtual mode can be eliminated from the operation reaction force, and output of an operation reaction force not expected in the game is avoided. That is, according to the present embodiment, it is possible to execute control suitable for using the operation member 20 in a game.

[0048] Furthermore, the controller 4 of this embodiment sets the first ratio R and the second axial force value Fa2 to 0. This sets an operation reaction force that is more appropriate for the virtual mode. The game machine 8 may function as, for example, a simulator for driving training. The technology of the present disclosure may also be applied to moving bodies other than electric vehicles. For example, the accelerator operation member 71 and / or the brake operation member 72 may be provided on the operation member 20.

[0049] (1st form) An example configuration of the present disclosure will be described below. A steering system 1 of a first embodiment of the present disclosure includes an operation device 2 including an operation member 20 for a user to operate the steering wheel and a reaction force applying device 25 that applies an operation reaction force to the operation member 20; a steering device 3 that is mechanically separated from the operation device 2 and steers the wheels in response to a supplied steering current; and a controller 4 that controls the steering device 3 and the reaction force applying device 25 based on an operation signal related to the operation of the operation member 20 received from the operation device 2. The steering system 1 is a steer-by-wire steering system that is switchable between a normal mode in which the wheels 11, 12 are steered based on the operation signal and a virtual mode in which a virtual moving object 8a created as a video is steered based on the operation signal. In the virtual mode, the controller 4 is configured to set the steering current to a current value at which the wheels 11, 12 do not turn regardless of the operation signal.

[0050] (2nd form) In the steering system 1 of the second embodiment of the present disclosure, in the configuration of the first embodiment, the controller 4 is configured to set the steering current to 0 in the virtual mode regardless of the operation signal.

[0051] (3rd form) In the steering system 1 of the third embodiment of the present disclosure, in the configuration of the second embodiment, the controller 4 uses a plurality of calculation terms P, D, M and a plurality of gains Gp, Gd, Gm in calculating the current value of the steering current Is. In the virtual mode, the controller 4 sets each of the calculation terms P, D, M to 0, or sets each of the gains Gp, Gd, Gm to 0.

[0052] (4th form) In steering system 1 of a fourth aspect of the present disclosure, in the configuration of the second aspect, controller 4 is configured to receive a steering angle signal related to the steering angle of wheels 11, 12 from steering device 3. Controller 4 calculates deviation term P based on an angle difference, which is the difference between a target steering angle corresponding to the operation signal and an actual steering angle corresponding to the steering angle signal, and a predetermined deviation term gain Gp. Controller 4 calculates speed term D based on a differential difference (speed difference), which is the difference between a time differential value of the target steering angle and a time differential value of the actual steering angle, and a predetermined speed term gain Gd. Controller 4 calculates damping term M based on the differential difference (speed difference) and a predetermined damping term gain Gm. Controller 4 calculates a steering torque command value Ts corresponding to the steering current based on a value obtained by subtracting damping term M from the sum of deviation term P and speed term D. In the virtual mode, the controller 4 (i) sets the deviation term P, the speed term D, and the damping term M to 0, (ii) sets the deviation term gain Gp, the speed term gain Gd, and the damping term gain Gm to 0, (iii) sets the steering torque command value Ts to 0, or (iv) sets the target steering angle to a predetermined constant value.

[0053] (5th form) In steering system 1 of a fifth aspect of the present disclosure, in one of the configurations of the first to fourth aspects, controller 4 is configured to receive a steering angle signal related to the steering angle of wheels 11, 12 from steering device 3, and to add compensation torque value Tc, which is set to increase as the angle difference, which is the difference between a target steering angle corresponding to the operation signal and an actual steering angle corresponding to the steering angle signal, increases, to a calculated value of operation reaction force calculated based on the operation signal. In virtual mode, controller 4 sets compensation torque value Tc to a predetermined torque value regardless of the angle difference.

[0054] (6th form) In the steering system 1 of the sixth embodiment of the present disclosure, the predetermined torque value is set to zero in the configuration of the fifth embodiment.

[0055] (7th form) In the steering system 1 according to the seventh aspect of the present disclosure, in one configuration among the first to sixth aspects, the steering device 3 includes a current sensor 351 that detects a steering current. When calculating the virtual axial force value Fv included in the operating reaction force, the controller 4 calculates a current axial force value Fi based on the detection value of the current sensor 351. The controller 4 calculates an angular axial force value Fa based on the sum of a first axial force value Fa1 based on the vehicle speed and the target steering angle and a second axial force value Fa2 related to the operating reaction force when the vehicle speed is equal to or lower than a predetermined speed. The controller 4 uses a first ratio R and a second ratio (1 - R) set so that the sum becomes 1, and adds a value obtained by multiplying the current axial force value Fi by the first ratio R and a value obtained by multiplying the angular axial force value Fa by the second ratio (1 - R) to calculate the virtual axial force value Fv. The first ratio R is set based on the vehicle speed and the steering angle signal. In the virtual mode, the controller 4 sets the first ratio R and the second axial force value Fa2 to 0, and sets the vehicle speed used in the calculation of the first axial force value Fa1 to a predetermined value. Setting the vehicle speed to a predetermined value corresponds to setting the vehicle speed gain Gs to a predetermined value.

[0056] (Eighth Aspect) In the steering system 1 according to the eighth aspect of the present disclosure, in one configuration among the first to sixth aspects, the steering device 3 includes a current sensor 351 that detects a steering current. The controller 4 is configured to receive an accelerator signal related to the operation of an accelerator operation member 71 for an accelerator operation provided in the vehicle and a brake signal related to the operation of a brake operation member 72 for a brake operation provided in the vehicle. When calculating the virtual axial force value Fv included in the operation reaction force, the controller 4 calculates a current axial force value Fi based on the detection value of the current sensor 351. The controller 4 calculates an angular axial force value Fa based on the sum of a first axial force value Fa1 based on the vehicle speed and the target steering angle and a second axial force value Fa2 corresponding to the operation reaction force when the vehicle speed is equal to or lower than a predetermined speed. The controller 4 uses a first ratio R and a second ratio (1 - R) set so that the sum becomes 1, multiplies the current axial force value Fi by the first ratio R, adds a value obtained by multiplying the angular axial force value Fa by the second ratio (1 - R), and calculates the virtual axial force value Fv. The first ratio R is set based on the vehicle speed and the steering angle signal. In the virtual mode, the controller 4 sets the vehicle speed used in the calculation of the first axial force value Fa1, the first ratio R (the vehicle speed used in the calculation value Cr), and / or the second axial force value Fa2 based on the accelerator signal or the brake signal.

Description of Signs

[0057] 1... Steering system, 11, 12... Wheels, 2... Operating device, 20... Operating member, 23... Operation amount sensor, 25... Reaction force applying device, 3... Steering device, 35... Steering motor, 351... Current sensor, 4... Controller, 71... Accelerator operation member, 72... Brake operation member, 8a... Virtual moving body.

Claims

1. An operating device including an operating member for a steering operation by a user and a reaction force applying device for applying a reaction force to the operating member, a steering device that is mechanically separated from the operating device and steers wheels according to a supplied steering current, a controller that controls the steering device and the reaction force applying device based on an operation signal regarding the operation of the operating member received from the operating device, A steer-by-wire type steering system including: a normal mode in which the wheels are steered based on the operation signal; and a virtual mode in which a virtual moving body created as an image is steered based on the operation signal, and the normal mode and the virtual mode are switchable, wherein the controller is configured to set the steering current to a current value at which the wheels do not steer regardless of the operation signal in the virtual mode, Steering system.

2. The steering system according to claim 1, wherein the controller is configured to set the steering current to 0 regardless of the operation signal in the virtual mode. The steering system according to claim 1.

3. The controller, uses a plurality of calculation terms and a plurality of gains in calculating the current value of the steering current, and sets each of the calculation terms to 0 or sets each of the gains to 0 in the virtual mode, The steering system according to claim 2.

4. The controller, is configured to receive a steering angle signal regarding the steering angle of the wheels from the steering device, calculates a first term based on an angle difference, which is a difference between a target steering angle corresponding to the operation signal and an actual steering angle corresponding to the steering angle signal, and a predetermined first gain, calculates a second term based on a differential difference, which is a difference between a time derivative value of the target steering angle and a time derivative value of the actual steering angle, and a predetermined second gain, calculates a third term based on the differential difference and a predetermined third gain, calculates a steering torque command value corresponding to the steering current based on a value obtained by subtracting the third term from the sum of the first term and the second term, The controller, in the virtual mode, (i) sets the first term, the second term, and the third term to 0 respectively, (ii) sets the first gain, the second gain, and the third gain to 0 respectively, (iii) sets the steering torque command value to 0, or (iv) sets the target steering angle to a predetermined constant value, The steering system according to claim 2.

5. The controller, Receiving a steering angle signal related to the steering angle of the wheel from the steering device, configured to add a compensation torque value set such that the greater the angle difference, which is the difference between the target steering angle corresponding to the operation signal and the actual steering angle corresponding to the steering angle signal, the greater the compensation torque value becomes with respect to the calculated value of the operation reaction force calculated based on the operation signal, in the virtual mode, setting the compensation torque value to a predetermined torque value regardless of the angle difference, The steering system according to any one of claims 1 to 4.

6. The predetermined torque value is 0, The steering system according to claim 5.

7. The steering device includes a current sensor that detects the steering current, The controller, when calculating the virtual axial force value included in the operation reaction force, calculating a current axial force value based on the detected value of the current sensor, calculating an angular axial force value based on the sum of a first axial force value based on the vehicle speed and the target steering angle and a second axial force value corresponding to the operation reaction force when the vehicle speed is equal to or lower than the predetermined speed, configured to calculate the virtual axial force value by adding a value obtained by multiplying the current axial force value by the first ratio and a value obtained by multiplying the angular axial force value by the second ratio, using the first ratio and the second ratio set such that the sum is 1, The first ratio is set based on the vehicle speed and the steering angle signal, The controller, in the virtual mode, setting the first ratio and the second axial force value to 0, setting the vehicle speed used in the calculation of the first axial force value to a predetermined value, The steering system according to claim 5.

8. The steering device includes a current sensor that detects the steering current, The controller, receiving an accelerator signal related to the operation of an accelerator operation member for accelerator operation provided in the vehicle and a brake signal related to the operation of a brake operation member for brake operation provided in the vehicle, when calculating the virtual axial force value included in the operation reaction force, calculating a current axial force value based on the detected value of the current sensor, calculating an angular axial force value based on the sum of a first axial force value based on the vehicle speed and the target steering angle and a second axial force value corresponding to the operation reaction force when the vehicle speed is equal to or lower than the predetermined speed, configured to calculate the virtual axial force value by adding a value obtained by multiplying the current axial force value by the first ratio and a value obtained by multiplying the angular axial force value by the second ratio, using the first ratio and the second ratio set such that the sum is 1, The first ratio is set based on the vehicle speed and the steering angle signal, The controller, in the virtual mode, sets the vehicle speed, the first ratio, and / or the second axial force value used in the calculation of the first axial force value based on the accelerator signal or the brake signal, The steering system according to claim 5.

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