Steering control device

Abstract

A steering control device (1) has a processing circuit (1A) that controls a reaction force motor (12) and a turning motor (31). The processing circuit can select a steering control mode from a normal mode and a play mode. The normal mode is a mode that is selected when actually causing a vehicle to travel. The play mode is a mode that is selected when performing simulated traveling using the vehicle or when a vehicle is used to perform an operation of a simulated vehicle. When the play mode is selected as the steering control mode, the processing circuit causes the steering control mode to transition from the play mode to the normal mode when it is detected that the vehicle is traveling, or when a sign that the vehicle starts traveling is detected.

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] International Publication No. 2024 / 069692

[0004] The automobile described in Patent Document 1 has the following concerns: When the entertainment mode is selected, the steering wheels of the automobile will not steer even if the steering wheel is operated. Furthermore, the selected mode continues until the automobile's main switch is turned off. Therefore, if the automobile starts moving for any reason while the entertainment mode is selected, there is a risk that the steering wheels will not be able to steer.

[0005] A steering control device according to one aspect of the present disclosure has a processing circuit configured to control a reaction force motor that generates a reaction force applied to a vehicle's control element and a steering motor that generates a steering force applied to a steering shaft, from which power transmission is separated to the control element. The processing circuit is configured to allow selection of a steering control mode from a normal mode and a play mode. The normal mode is selected when the vehicle is actually driven and controls the steering motor so that the steering wheels turn according to the operation state of the control element. The play mode is selected when the vehicle is used for simulated driving or when the vehicle is used to operate a simulated vehicle and controls the steering motor so that the steering wheels do not turn regardless of the operation state of the control element. When the play mode is selected as the steering control mode, the processing circuit is configured to transition the steering control mode from the play mode to the normal mode when it is detected that the vehicle is moving or when an indication that the vehicle is about to start moving is detected.

[0006] Figure 1 is a configuration diagram of a steering system equipped with a steering control device according to one embodiment. Figure 2 is a transition diagram showing the transition of steering control modes of the steering control device according to one embodiment. Figure 3 is a transition diagram showing the transition of steering control modes of the steering control device according to one embodiment.

[0007] A steering control device according to one 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 mechanism 4 is a mechanism that steers the steering wheels 6 of the vehicle 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.

[0008] 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.

[0009] 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.

[0010] 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.

[0011] As the steering shaft 22 moves axially, the steering angle θ of the steering wheel 6 changes. ｗThis 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.

[0012] The steering control device 1 has a processing circuit 1A that includes one of the following three configurations A1, A2, and A3: A1. One or more processors that operate according to a computer program which is software. The processor includes a CPU (Central Processing Unit) and memory.

[0013] A2. One or more dedicated circuits, such as application-specific integrated circuits (ASICs), that perform at least some of the various processes. The ASIC may include a CPU and memory. A3. A circuit that combines configurations A1 and A2.

[0014] Memory is a medium readable by a computer that stores programs describing 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.

[0015] The processing circuit 1A acquires the detection results from the on-board sensors. The sensors include a vehicle speed sensor 41, a torque sensor 42, a first rotation angle sensor 43, and a second rotation angle sensor 44. The vehicle speed sensor 41 detects the vehicle speed V. The vehicle speed V is a state variable that reflects the driving state of the vehicle.

[0016] The torque sensor 42 is provided 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 measures the steering torque T applied to the steering shaft 11. ｈ It detects steering torque T. ｈis calculated based on the amount of torsion of the torsion bar 42a provided on the steering shaft 11. The steering torque T ｈ is a state variable that reflects the steering state of the steering wheel 5.

[0017] The first rotation angle sensor 43 is provided on the reaction force motor 12. The first rotation angle sensor 43 detects the rotation angle θ ａ of the reaction force motor 12. The second rotation angle sensor 44 is provided on the steering motor 31. The second rotation angle sensor 44 detects the rotation angle θ ｂ of the steering motor 31.

[0018] The processing circuit 1A executes reaction force control. The reaction force control is control for generating a steering reaction force corresponding to the steering torque T ｈ in the reaction force motor 12. The processing circuit 1A uses, for example, the vehicle speed V detected by the vehicle speed sensor 41, the steering torque T ｈ detected by the torque sensor 42, and the rotation angle θ ａ of the reaction force motor 12 detected by the first rotation angle sensor 43 to control the operation of the reaction force motor 12. The processing circuit 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 ｈ in the reaction force motor 12.

[0019] The processing circuit 1A executes steering control. The steering control is control for steering the steered wheels 6 according to the steering state of the steering wheel 5. The processing circuit 1A uses, for example, the rotation angle θ ｂ of the steering motor 31 detected by the second rotation angle sensor 44 to control the operation of the steering motor 31. The processing circuit 1A 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.

[0020] The processing circuit 1A is interconnected with the vehicle control device 52 via the in-vehicle network 51. The vehicle control device 52, like the steering control device 1, has a processing circuit that includes one of the three configurations A1, A2, and A3 described above. The in-vehicle network is, for example, a CAN (Controller Area Network). The steering control device 1 and the vehicle control device 52 exchange information with each other via the in-vehicle network. Based on the information exchanged with the vehicle control device 52, the processing circuit 1A controls the driving of the reaction force motor 12 and the steering motor 31.

[0021] The vehicle control device 52 controls various devices mounted on the vehicle. These devices include, for example, a drive source, a braking system, and a display device. The drive source is, for example, at least one of an engine and a motor. The braking system generates 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.

[0022] The vehicle control device 52 has a first function for controlling the actual movement of a vehicle, as well as a second function for controlling the movement of a simulated vehicle. The vehicle user can select either the first or second function by operating a selection switch after, for example, turning on the vehicle's power. The selection switch may be a mechanical switch located inside the vehicle cabin, or it may be a virtual switch displayed on a touch panel screen.

[0023] When the second function is selected, the vehicle control device 52 can perform various simulations using an actual vehicle. These simulations include, for example, simulations for educational training or simulated driving experience, such as driving simulators, and simulations for entertainment purposes, such as racing games using simulated vehicles. The simulated vehicle may be, for example, a virtual vehicle displayed on the screen of a display device. The vehicle control device 52 controls the movement of the virtual vehicle displayed on the screen in response to the operation of various devices such as the steering wheel 5, accelerator pedal, and brake pedal.

[0024] The vehicle control device 52 generates steering mode information SMI depending on whether the first function or the second function is selected. The steering mode information SMI is a command to the processing circuit 1A indicating whether the first function or the second function is selected. The steering mode information SMI may be, for example, a flag. If the first function is selected, the vehicle control device 52 sets the value of the steering mode information SMI to "0". If the second function is selected, the vehicle control device 52 sets the value of the steering mode information SMI to "2".

[0025] The processing circuit 1A receives steering mode information SMI generated by the vehicle control device 52. The processing circuit 1A switches the steering control mode according to the steering mode information SMI. The steering control mode is selected from, for example, normal mode and play mode.

[0026] 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 processing circuit 1A performs normal reaction force control and steering control. In other words, the normal mode is also a mode in which the steering motor 31 is controlled so that the steering wheels 6 turn according to the steering state of the steering wheel 5. For this reason, the steering wheel 5 has a steering torque T ｈA steering reaction force is applied accordingly. This makes it possible to give the vehicle user a moderate sense of feedback. The steering wheel 6 steers according to the steering state of the steering wheel 5.

[0027] 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 processing circuit 1A performs reaction force control, but does not perform steering control. The steering wheel 5 is operated, for example, according to the content displayed on the display device screen.

[0028] The steering wheel 5 has a steering torque T ｈ A steering reaction force is applied accordingly. As a result, the vehicle user can feel a steering reaction force corresponding to the content displayed on the display screen, for example, as a tactile sensation through the steering wheel 5. Not performing steering control means, for example, forcibly limiting the current supplied to the steering motor 31 to "0" regardless of the steering state of the steering wheel 5. As a result, the steering wheels 6 do not steer regardless of the steering state of the steering wheel 5. Play mode is also a mode in which the steering motor 31 is controlled so that the steering wheels 6 do not steer regardless of the operating state of the steering wheel 5.

[0029] <First example of steering control mode transition> Next, a first example of steering control mode transition will be described. As shown in Figure 2, the processing circuit 1A starts up when the vehicle's power is turned on and selects a steering control mode. The processing circuit 1A selects a steering control mode based on the steering mode information SMI generated by the vehicle control device 52.

[0030] If the steering mode information SMI is "0", that is, if the first function of the vehicle control device 52 is selected, the processing circuit 1A transitions the steering control mode to the normal mode.

[0031] If the steering mode information SMI is "1", that is, if the second function of the vehicle control device 52 is selected, the processing circuit 1A transitions the steering control mode to play mode.

[0032] When the steering control mode is in normal mode, the processing circuit 1A terminates processing when the first termination condition is met. The first termination condition is, for example, that either of the two main conditions B1 and B2 is met.

[0033] B1. The vehicle's power is turned off. B2. All three subconditions B21, B22, and B23 are met. B21. The steering mode information SMI indicates that the second function of the vehicle control device 52 has been selected. That is, the value of the steering mode information SMI is "1".

[0034] B22. The vehicle is stationary. Processing circuit 1A determines that the vehicle is stationary if the vehicle speed V is less than the vehicle speed threshold. The vehicle speed threshold is the criterion for determining whether the vehicle is moving or not.

[0035] B23. The transmission's shift range is the parking range. The parking range is the shift range used when parking. When the steering control mode is play mode, the processing circuit 1A terminates processing when the second termination condition is met. The second termination condition is, for example, that either of the two main conditions C1 or C2 is met.

[0036] C1. The vehicle is stationary. C2. Both subconditions C21 and C22 are met. C21. The steering mode information SMI indicates that the first function of the vehicle control device 52 has been selected. That is, the value of the steering mode information SMI is "0".

[0037] Completion of the execution of rudder angle synchronization processing. The rudder angle synchronization processing is control for automatically adjusting the rotational position of the steering wheel 5, and is control for synchronizing the positional relationship between the steering wheel 5 and the steering wheel 6 to the original positional relationship according to a predetermined rudder angle ratio. The processing circuit 1A executes the rudder angle synchronization processing, for example, when the power supply of the vehicle is turned on. The processing circuit 1A also executes the rudder angle synchronization processing when the steering mode information SMI switches from indicating that the second function of the vehicle control device 52 is selected to indicating that the first function is selected.

[0038] When the steering control mode is the play mode, the processing circuit 1A transitions the steering control mode from the play mode to the normal mode when the mode transition condition is satisfied. The mode transition condition is, for example, that at least one of two main conditions D1 and D2 is satisfied.

[0039] D1. The vehicle speed V is equal to or higher than the vehicle speed threshold. When the vehicle speed V is equal to or higher than the vehicle speed threshold, the processing circuit 1A determines that the vehicle is traveling. D2. The shift range of the transmission is the drive range. The drive range is the shift range when the vehicle is moving forward. The switching of the shift range to the drive range is one of the signs that the vehicle is about to start traveling.

[0040] <Second transition example of the steering control mode> Next, a second transition example of the steering control mode will be described. The second transition example is an example of the case where the steering control mode is transitioned from the normal mode to the play mode.

[0041] As shown in FIG. 3, when the steering control mode is transitioned from the normal mode to the play mode, the user of the vehicle first selects the second function of the vehicle control device 52 by operating the selection switch. The second function is a function for performing simulation, that is, running control of a virtual vehicle.

[0042] Next, the vehicle user stops the vehicle and switches the transmission's shift range to the parking range. As a result, all three subconditions B21, B22, and B23 are met, and the first termination condition is satisfied. Therefore, the processing circuit 1A terminates processing in normal mode.

[0043] Since the vehicle's power is not turned off, the processing circuit 1A remains running. Also, the second function of the vehicle control device 52 has already been selected by the vehicle's user. Therefore, the steering mode information SMI indicates that the second function of the vehicle control device 52 has been selected. Consequently, the processing circuit 1A selects play mode as the steering control mode.

[0044] <Effects of the Embodiment> According to this embodiment, the following effects are achieved. (1) The processing circuit 1A controls a reaction force motor 12 that generates a reaction force applied to the vehicle's control element, and a steering motor 31 that generates a steering force applied to the steering shaft 22, which is separated from the control element by power transmission. The processing circuit 1A can select a steering control mode from a normal mode and a play mode. The control element is, for example, a steering wheel 5.

[0045] The normal mode is selected when the vehicle is actually driven, and controls the steering motor 31 so that the steering wheels 6 turn according to the operation state of the control panel. The play mode is selected when performing simulated driving using the vehicle, or when operating a simulated vehicle using the vehicle, and controls the steering motor so that the steering wheels 6 do not turn regardless of the operation state of the control panel.

[0046] When play mode is selected as the steering control mode, the processing circuit 1A transitions the steering control mode from play mode to the normal mode when it detects that the vehicle is moving or when it detects signs that the vehicle is about to start moving. With this configuration, the steering control mode is appropriately switched according to the state of the vehicle. Therefore, even if the vehicle starts moving unintentionally while play mode is selected, the steering wheels 6 can be appropriately steered according to the steering state of the steering wheel 5.

[0047] (2) The processing circuit 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 SMI. When the normal mode is selected as the steering control mode, the processing circuit 1A transitions the steering control mode to play mode only when the vehicle is in a state where it cannot move, and when the command requests the selection of play mode as the steering control mode. With this configuration, it is possible to suppress the transition of the steering control mode from normal mode to play mode when the vehicle is in a state where it can move, or when the vehicle is moving. As a result, the steering wheels 6 can be appropriately steered according to the steering state of the steering wheel 5.

[0048] (3) The processing circuit 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 SMI. When play mode is selected as the steering control mode, the processing circuit 1A performs steering angle synchronization processing if the command requests that the normal mode be selected as the steering control mode. After the execution of the steering angle synchronization processing is completed, the processing circuit 1A terminates the processing in play mode. The steering angle synchronization processing is a process that corrects the operating position of the control unit so that the operating position of the control unit corresponds to the steering position of the steering wheel. The control unit is, for example, the steering wheel 5. With this configuration, after the operating position of the control unit and the steering position of the steering wheel 6 are matched, the processing in play mode can be terminated appropriately.

[0049] (4) The processing circuit 1A determines that the vehicle is moving if the vehicle speed V is equal to or greater than the vehicle speed threshold. With this configuration, it is possible to appropriately determine whether the vehicle is moving based on the vehicle speed V.

[0050] (5) An indication that the vehicle is about to start moving is that the vehicle's shift range has been switched to a shift range that allows the vehicle to move. The shift range that allows the vehicle to move is, for example, the drive range. As this configuration shows, the state of the shift range is suitable for determining whether the vehicle is about to start moving.

[0051] <Other Embodiments> This embodiment may be implemented with the following modifications: - When the steering control mode makes an emergency transition from play mode to normal mode, the steering angle synchronization process is not performed. For this reason, if the vehicle is equipped with an automatic driving system, the processing circuit 1A may control the steering mechanism 4 to move the vehicle, for example, to the shoulder of the road. An automatic driving system is a vehicle system that realizes an automatic driving function in which the system takes over the driving of the vehicle. After this, the processing circuit 1A may, for example, perform the steering angle synchronization process when the vehicle is stopped and the steering wheel 5 has not been steered for a set time or longer. Once the execution of the steering angle synchronization process is complete, the processing circuit 1A controls the steering mechanism 4 so that the steering wheels 6 are synchronized with the steering state of the steering wheel 5.

[0052] - 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.

[0053] - 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.

[0054] The main condition D2 constituting the mode transition condition may be that the transmission's shift range is switched to a shift range other than the parking range. Shift ranges other than the parking range include, for example, the drive range, reverse range, or neutral range. The reverse range is the shift range used when moving the vehicle in reverse. The neutral range is the shift range in which power transmission between the vehicle's drive source and the drive wheels is interrupted.

[0055] The parking and neutral ranges are shift ranges in which the vehicle cannot be driven by the power source. However, when the shift range is in the neutral range, the vehicle may move if an external force is applied to it. The reverse and drive ranges are shift ranges in which the vehicle can be driven by the power source.

[0056] The main condition D2 constituting the mode transition condition may be the release of the parking brake provided on the vehicle. The parking brake is not used for braking or stopping the vehicle, but rather for keeping the wheels still when parked or stopped. The parking brake is released when the vehicle starts moving. In other words, the release of the parking brake is one of the signs that the vehicle is about to start moving. The state of the parking brake is suitable for determining whether the vehicle will start moving or not.

[0057] 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 having a processing circuit configured to control a reaction force motor that generates a reaction force applied to a vehicle's control element and a steering motor that generates a steering force applied to a steering shaft from which power transmission to the control element is separated, wherein the processing circuit is configured to allow selection of a steering control mode from a normal mode and a play mode, wherein the normal mode is selected when the vehicle is actually driven and controls the steering motor so that the steering wheels turn according to the operating state of the control element, wherein the play mode is selected when the vehicle is used for simulated driving or when the vehicle is used for operating a simulated vehicle and controls the steering motor so that the steering wheels do not turn regardless of the operating state of the control element, wherein the processing circuit is configured to transition the steering control mode from the play mode to the normal mode when the vehicle is detected to be in motion or when an indication that the vehicle is about to start moving is detected.

2. The steering control device according to claim 1, wherein the processing circuit is configured to select the steering control mode based on a command from a vehicle control device mounted on the vehicle, and the processing circuit is configured to transition the steering control mode to the play mode only when the vehicle is in a state where it cannot move, when the normal mode is selected as the steering control mode and the command requests the selection of the play mode as the steering control mode.

3. The steering control device according to claim 1, wherein the processing circuit is configured to select the steering control mode based on a command from a vehicle control device mounted on the vehicle, and when the play mode is selected as the steering control mode, the processing circuit is configured to perform steering angle synchronization processing when the command requests the selection of the normal mode as the steering control mode, and to terminate the processing in play mode after the completion of the steering angle synchronization processing, and the steering angle synchronization processing is a process of correcting the operating position of the operator so that the operating position of the operator corresponds to the steering position of the steering wheel.

4. The steering control device according to any one of claims 1 to 3, wherein the processing circuit is configured to determine that the vehicle is moving when the vehicle speed is equal to or greater than a vehicle speed threshold.

5. The steering control device according to any one of claims 1 to 3, wherein the warning sign is that the shift range of the vehicle has been switched to a shift range that allows the vehicle to be driven, or that the parking brake provided on the vehicle has been released.

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