Steering control device

Abstract

The present application provides a steering control device including a control circuit configured to control driving of a reaction force motor (21) that generates a steering reaction force applied to a steering wheel (11) with which power transmission to a steering wheel (15) of a vehicle is separated. When a power source of the vehicle is turned on, the control circuit requests a vehicle control device (60) to stop running of the vehicle while the vehicle control device (60) exchanges information in a manner that does not follow a predetermined pattern.

Description

Technical Field

[0001] This invention relates to a steering control device. Background Technology

[0002] There exists a so-called steer-by-wire system in which the power transmission between the steering wheel and the steering wheels is separated (see, for example, Japanese Unexamined Patent Application Publication No. 2006-321434 A). This steering system includes a reaction force mechanism and a steering mechanism. The reaction force mechanism has a reaction force motor, which is the source of generating a steering reaction force applied to the steering shaft; the steering mechanism has a steering motor, which is the source of generating a steering force for turning the steering wheels. When the vehicle is in motion, the steering system's control unit generates a steering reaction force by controlling the power supply to the reaction force motor, and turns the steering wheels by controlling the power supply to the steering motor. Summary of the Invention

[0003] Vehicles are required to have enhanced crime prevention capabilities. Steering systems installed on vehicles are also required to have enhanced crime prevention capabilities.

[0004] According to one aspect of the invention, a steering control device includes: a control circuit configured to control the drive of a reaction force motor that generates a steering reaction force applied to a steering wheel, wherein power transmission between the steering wheel and the vehicle's steering wheels is separated. When the vehicle power is turned on, the control circuit requests the vehicle control device, which controls the vehicle's movement, to stop the vehicle's movement when exchanging information with the vehicle control device in a manner that does not follow a predetermined pattern.

[0005] There is a problem that the information exchanged between the steering control unit and the vehicle control unit can be forged due to fraudulent activities. In this regard, the above configuration can suppress vehicle movement when the control circuit and the vehicle control unit exchange information in a manner that does not follow a predetermined pattern. Therefore, crime prevention performance is improved.

[0006] In the above aspects, when the preparatory process, which is triggered by turning on the vehicle power, is completed, the control circuit can allow the vehicle control device to switch the vehicle to a drivable state and then to a normal control state. In the normal control state, when the vehicle control device recognizes that the vehicle is in a drivable state, reaction force control is executed to generate steering reaction force by the reaction force motor.

[0007] With the above configuration, once the preparation process for reaction force control is complete, the steering control unit allows the vehicle control unit to turn the vehicle into a drivable state. In other words, the vehicle control unit waits until the steering control unit allows the vehicle to turn into a drivable state before proceeding. For this reason, the vehicle can only move after the steering control unit's preparation process is complete. Therefore, the driver can begin driving the vehicle in a safer state.

[0008] In the above configuration, when the vehicle control device recognizes that the vehicle is in a drivable state, the control circuit can request the vehicle control device to stop the vehicle from moving, even if the vehicle control device is not allowed to switch the vehicle to a drivable state.

[0009] When a vehicle is identified as drivable, but the steering control does not allow the vehicle control to transition to a drivable state, the authorization to the vehicle control could be forged, for example, through fraudulent impersonation. In this regard, with the above configuration, when the authorization to the vehicle control could be forged, the vehicle control is requested to stop the vehicle's movement. By stopping the vehicle in response to a request from the steering control, crime prevention performance is improved.

[0010] In the above configuration, the preparation process may include: under the premise that the steering range of the steering wheel is limited to less than 360°, operating the steering wheel to the first operating end, and then operating the steering wheel in the opposite direction to the second operating end, in order to learn the midpoint learning process of the steering wheel's neutral steering position; and the steering wheel rotation position correction process to make the steering wheel rotation position synchronized with the steering wheel's rotation position.

[0011] For example, when the vehicle begins to move but the steering control is in the middle of performing midpoint learning or steering angle synchronization processing, the driver may find it difficult to turn the steering wheel in the intended direction. This is because the steering wheel is in an automatic rotation state during midpoint learning or steering angle synchronization processing. In this regard, with the above configuration, the steering control allows the vehicle control to bring the vehicle to a drivable state once the preparatory processing for reaction force control is complete. For this reason, the vehicle can only move after the preparatory processing of the steering control has been completed. Therefore, the driver can begin driving the vehicle in a safer state. There is no discomfort for the driver.

[0012] In the above aspects, the vehicle control unit can control the starting of the powertrain, including the drive source for driving the vehicle. With the above configuration, when the vehicle control unit controls the starting of the vehicle's powertrain, the vehicle can be brought into a drivable state.

[0013] Through the aforementioned steering control devices, crime prevention performance can be further improved. Attached Figure Description

[0014] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and in the drawings:

[0015] Figure 1 This is a configuration diagram of a steer-by-wire device according to an embodiment equipped with a steering control device;

[0016] Figure 2 This is a block diagram of the reaction force control device and the steering control device according to the implementation method;

[0017] Figure 3 This is a time diagram showing a comparative example of the activation sequences in the reaction force control device and the vehicle control device;

[0018] Figure 4 This is a flowchart illustrating the process by which the reaction force control device, according to an embodiment, determines the start permission of the vehicle's powertrain.

[0019] Figure 5 This is a time diagram showing the first mode of the activation sequence in the reaction force control device and the vehicle control device according to the embodiments;

[0020] Figure 6 This is a flowchart illustrating the process of determining a vehicle stop request by the reaction force control device according to an embodiment; and

[0021] Figure 7 This is a time diagram showing the second mode of the activation sequence in the reaction force control device and vehicle control device according to the embodiment. Detailed Implementation

[0022] The following describes a first embodiment in which the steering control device is implemented as a steer-by-wire device. For example... Figure 1 As shown, the vehicle's steering system 10 has a steering shaft 12 connected to the steering wheel 11. The steering system 10 also has a steering shaft 12 along the vehicle's width direction ( Figure 1 A steering shaft 13 extends in the left-right direction. Both ends of the steering shaft 13 are connected to the steering wheels 15 via tie rods 14. With the linear movement of the steering shaft 13, the steering angle θ of the steering wheels 15... w Change. Steering shaft 12 and steering shaft 13 constitute the vehicle's steering mechanism. Figure 1 Only the steering wheel 15 on one side is shown.

[0023] The steering system 10 includes a reaction force motor 21 and a reduction gear 22. The reaction force motor 21 is the source of the steering reaction force. The steering reaction force is a force acting in the opposite direction to the direction in which the driver operates the steering wheel 11. The rotation shaft of the reaction force motor 21 is connected to the steering shaft 12 via the reduction gear 22. The torque of the reaction force motor 21 is applied to the steering shaft 12 as the steering reaction force. By applying the steering reaction force to the steering wheel 11, the driver can be given an appropriate sense of response.

[0024] The reaction motor 21 is, for example, a three-phase brushless motor. The reaction motor 21 has a first system winding group N11 and a second system winding group N12. The first system winding group N11 and the second system winding group N12 are wound around a common stator (not shown). The first system winding group N11 and the second system winding group N12 have the same electrical characteristics.

[0025] The steering system 10 includes a steering motor 31 and a reduction gear 32. The steering motor 31 is the source of steering force. The steering force is the power used to turn the steering wheel 15. The rotation shaft of the steering motor 31 is connected to a pinion shaft 33 via the reduction gear 32. The pinion teeth 33a of the pinion shaft 33 mesh with the rack teeth of the steering shaft 13. The torque of the steering motor 31 is applied to the steering shaft 13 as a steering force via the pinion shaft 33. As the steering motor 31 rotates, the steering shaft 13 moves in the vehicle width direction.

[0026] The steering motor 31 is, for example, a three-phase brushless motor. The steering motor 31 has a first system winding group N21 and a second system winding group N22. The first system winding group N21 and the second system winding group N22 are wound around a common stator (not shown). The first system winding group N21 and the second system winding group N22 have the same electrical characteristics.

[0027] The steering system 10 includes a reaction force control device 40. The reaction force control device 40 controls the drive of the reaction force motor 21, which is the control target. The reaction force control device 40 performs reaction force control so that the reaction force motor 21 generates a steering reaction force according to the steering torque Th. The reaction force control device 40 calculates the target steering reaction force based on the steering torque Th detected by the torque sensor 23, which is mounted on the steering shaft 12. The reaction force control device 40 controls the power supply to the reaction force motor 21 so that the actual steering reaction force applied to the steering shaft 12 matches the target steering reaction force. The reaction force control device 40 independently controls the power supply to the winding assembly of each of the two systems in the reaction force motor 21.

[0028] The reaction force control device 40 has a first system circuit 41 and a second system circuit 42. The first system circuit 41 controls the power supply to the winding group N11 of the first system in the reaction force motor 21 based on the steering torque Th detected by the torque sensor 23. The second system circuit 42 controls the power supply to the winding group N12 of the second system in the reaction force motor 21 based on the steering torque Th detected by the torque sensor 23.

[0029] The reaction force control device 40 and the in-vehicle control device 60 are interconnected via an in-vehicle network 61. The in-vehicle network 61 is, for example, a Controller Area Network (CAN). The reaction force control device 40 and the in-vehicle control device 60 exchange information with each other via the in-vehicle network 61. The vehicle control device 60 controls the movement of the vehicle. Specifically, the vehicle control device 60 controls, for example, the vehicle's powertrain. The powertrain includes a drive source for the vehicle's movement and a power transmission mechanism. The drive source for movement includes, for example, an engine or a motor. The power transmission mechanism is a mechanism that transmits the power generated by the drive source for movement to the drive wheels. The reaction force control device 40 controls the drive of the reaction force motor 21 based on the information exchanged with the vehicle control device 60.

[0030] The steering device 10 includes a steering control device 50. The steering control device 50 controls the drive of the steering motor 31, which is the control target. The steering control device 50 performs steering control so that the steering motor 31 generates a steering force to turn the steering wheels 15 according to the steering state. The steering control device 50 uses the steering angle θ detected by the steering angle sensor 24. s The travel Xw of the steering shaft 13 is detected by the travel sensor 34. Travel Xw is the displacement of the steering shaft 13 with reference to the neutral position, and reflects the steering angle θ. w The state variables are: The steering angle sensor 24 is positioned between the torque sensor 23 and the reduction gear 22 on the steering shaft 12. The stroke sensor 34 is positioned near the steering shaft 13.

[0031] Steering control device 50 is based on steering angle θ detected by steering angle sensor 24 s The target steering angle of the steering wheel 15 is calculated. The steering control unit 50 calculates the steering angle θ based on the travel Xw of the steering shaft 13 detected by the travel sensor 34. w The steering control unit 50 controls the power supply to the steering motor 31 to adjust the steering angle θ calculated based on the travel Xw. w Matching the target steering angle. The steering control unit 50 independently controls the power supply to the winding group of each of the two systems in the steering motor 31.

[0032] The steering control device 50 has a first system circuit 51 and a second system circuit 52. The first system circuit 51 is based on the steering angle θ detected by the steering angle sensor 24. s The power supply to the winding group N21 of the first system in the steering motor 31 is controlled by the travel Xw of the steering shaft 13 detected by the travel sensor 34. The second system circuit 52 is based on the steering angle θ detected by the steering angle sensor 24. s The power supply to the winding group N22 of the second system in the steering motor 31 is controlled by the travel Xw of the steering shaft 13 detected by the travel sensor 34.

[0033] By integrating the reaction force control device 40 and the reaction force motor 21, a so-called electromechanical integrated reaction force actuator can be configured. Furthermore, by integrating the steering control device 50 and the steering motor 31, a so-called electromechanical integrated steering actuator can be configured. The reaction force control device 40 and the steering control device 50 constitute the steering control device.

[0034] Reaction force control device

[0035] Next, the configuration of the reaction force control device will be described in detail. For example... Figure 2 As shown, the reaction force control device 40 has a first system circuit 41 and a second system circuit 42. The first system circuit 41 has a first reaction force control circuit 41A and a motor drive circuit 41B. The second system circuit 42 has a second reaction force control circuit 42A and a motor drive circuit 42B.

[0036] The first reaction force control circuit 41A comprises processing circuitry including: 1. one or more processors operating according to a computer program (software); 2. one or more dedicated hardware circuits, such as application-specific integrated circuits (ASICs), that execute at least some of various types of processing; and 3. combinations thereof. The processor includes a central processing unit (CPU). The processor also includes memory, such as random access memory (RAM) and read-only memory (ROM). The memory stores program code or commands configured to cause the CPU to perform processing. Memory, i.e., non-transitory computer-readable medium, includes any available medium that can be accessed by a general-purpose computer or a special-purpose computer.

[0037] The first reaction force control circuit 41A calculates the target steering reaction force to be generated in the reaction force motor 21 based on the steering torque Th detected by the torque sensor 23, and calculates a first current command value for the winding group N11 of the first system based on the calculated target steering reaction force value. However, the first current command value is set to half (50%) of the current amount (100%) required for the reaction force motor 21 to generate the target steering reaction force. The first reaction force control circuit 41A performs current feedback control, wherein the actual current value supplied to the winding group N11 of the first system follows the first current command value to generate a drive signal (PWM signal) for the motor drive circuit 41B.

[0038] The motor drive circuit 41B is a PWM inverter, in which three pins corresponding to the three phases (U, V, W) are connected in parallel, and switching elements, such as two field-effect transistors (FETs), are connected in series as the pins of the basic unit. The motor drive circuit 41B switches the switching elements of each phase based on a drive signal generated by the first reaction force control circuit 41A to convert DC power supplied from the battery into three-phase AC power. The three-phase AC power generated by the motor drive circuit 41B is supplied to the winding group N11 of the first system of the reaction force motor 21 via the power supply path of each phase (e.g., a busbar or cable). Therefore, the winding group N11 of the first system generates torque according to the first current command value.

[0039] The second reaction force control circuit 42A has essentially the same configuration as the first reaction force control circuit 41A. The second reaction force control circuit 42A calculates the target steering reaction force to be generated in the reaction force motor 21 based on the steering torque Th detected by the torque sensor 23, and calculates a second current command value for the winding group N12 of the second system based on the calculated target steering reaction force value. However, the second current command value is set to half (50%) of the current required for the reaction force motor 21 to generate the target steering reaction force. The second reaction force control circuit 42A performs current feedback control, wherein the actual current supplied to the winding group N12 of the second system follows the second current command value to generate the drive signal for the motor drive circuit 42B.

[0040] Motor drive circuit 42B has essentially the same configuration as motor drive circuit 41B. Motor drive circuit 42B converts DC power supplied from the battery into three-phase AC power based on a drive signal generated by the second reaction force control circuit 42A. The three-phase AC power generated by motor drive circuit 42B is supplied to the winding group N12 of the second system of reaction force motor 21 via the power supply path of each phase (e.g., busbar or cable). Therefore, the winding group N12 of the second system generates torque according to the second current command value. The reaction force motor 21 generates a total torque produced by the torque produced by the winding group N11 of the first system and the torque produced by the winding group N12 of the second system.

[0041] Depending on the product specifications, there may be a master-slave relationship between the first system circuit 41 and the second system circuit 42 of the reaction force control device 40. For example, in this case, the first system circuit 41 can act as the master circuit, and the second system circuit 42 can act as the slave circuit. Furthermore, depending on the product specifications, the first system circuit 41 and the second system circuit 42 can have an equal relationship.

[0042] Steering control unit

[0043] Next, the configuration of the steering control device 50 will be described in detail. For example... Figure 2 As shown, the steering control device 50 has a first system circuit 51 and a second system circuit 52. The first system circuit 51 has a first steering control circuit 51A and a motor drive circuit 51B. The second system circuit 52 has a second steering control circuit 52A and a motor drive circuit 52B.

[0044] The first steering control circuit 51A has essentially the same configuration as the first reaction force control circuit 41A. The first steering control circuit 51A is based on the steering angle θ detected by the steering angle sensor 24. s The target steering angle of the steering wheel 15 is calculated. The steering control unit 50 calculates the steering angle θ based on the travel Xw of the steering shaft 13 detected by the travel sensor 34. w The first steering control circuit 51A executes the steering angle θ calculated based on the travel Xw. w The target steering force to be generated in the steering motor 31 is calculated using angle feedback control following the target steering angle, and a third current command value for the winding group N21 of the first system of the steering motor 31 is calculated based on the calculated target steering force value. However, the third current command value is set to half (50%) of the current required for the steering motor 31 to generate the target steering force. The first steering control circuit 51A executes current feedback control, in which the actual current supplied to the winding group N21 of the first system follows the third current command value, to generate a drive signal for the motor drive circuit 51B.

[0045] Motor drive circuit 51B has essentially the same configuration as motor drive circuit 41B. Based on the drive signal generated by the first steering control circuit 51A, motor drive circuit 51B converts DC power supplied from the battery into three-phase AC power. The three-phase AC power generated by motor drive circuit 51B is supplied to the winding group N21 of the first system of steering motor 31 through the power supply path of each phase (e.g., busbar or cable). Therefore, the winding group N21 of the first system generates torque according to the third current command value.

[0046] The second steering control circuit 52A has essentially the same configuration as the first reaction force control circuit 41A. The second steering control circuit 52A is based on the steering angle θ detected by the steering angle sensor 24. s The target steering angle of the steering wheel 15 is calculated. The steering control unit 50 calculates the steering angle θ based on the travel Xw of the steering shaft 13 detected by the travel sensor 34. w The second steering control circuit 52A executes the steering angle θ calculated based on the stroke Xw. w The angle feedback control, following the target steering angle, calculates the target steering force to be generated in the steering motor 31, and calculates a fourth current command value for the winding group N22 of the second system of the steering motor 31 based on the calculated target steering force value. However, the fourth current command value is set to half (50%) of the current required for the steering motor 31 to generate the target steering force. The second steering control circuit 52A performs current feedback control, in which the actual current supplied to the winding group N22 of the second system follows the fourth current command value, to generate a drive signal for the motor drive circuit 52B.

[0047] Motor drive circuit 52B has essentially the same configuration as motor drive circuit 41B. Based on the drive signal generated by the second steering control circuit 52A, motor drive circuit 52B converts DC power supplied from the battery into three-phase AC power. The three-phase AC power generated by motor drive circuit 52B is supplied to the winding group N22 of the second system of steering motor 31 through the power supply path of each phase (e.g., busbar or cable). Therefore, the winding group N22 of the second system generates torque according to the fourth current command value. Steering motor 31 generates a total torque consisting of the torque generated by the winding group N21 of the first system and the torque generated by the winding group N22 of the second system.

[0048] Depending on the product specifications, there may be a master-slave relationship between the first system circuit 51 and the second system circuit 52 of the steering control device 50. For example, in this case, the first system circuit 51 can act as the master circuit, and the second system circuit 52 can act as the slave circuit. Furthermore, depending on the product specifications, the first system circuit 51 and the second system circuit 52 can have an equal relationship.

[0049] Communication path

[0050] Next, the communication paths within the reaction force control device 40 and the steering control device 50, as well as the communication path between the reaction force control device 40 and the steering control device 50, will be described.

[0051] like Figure 2 As shown, the first reaction force control circuit 41A and the second reaction force control circuit 42A exchange information with each other via communication line L1. This information includes abnormal information from the first reaction force control circuit 41A, the second reaction force control circuit 42A, or the motor drive circuits 41B and 42B. The information also includes flag values ​​indicating various states. The first reaction force control circuit 41A and the second reaction force control circuit 42A cooperate based on the information exchanged to control the drive of the reaction force motor 21.

[0052] The first steering control circuit 51A and the second steering control circuit 52A exchange information with each other via communication line L2. This information includes abnormal information from the first steering control circuit 51A and the second steering control circuit 52A, or from the motor drive circuits 51B and 52B. The information also includes flag values ​​indicating various states. The first steering control circuit 51A and the second steering control circuit 52A cooperate based on the information exchanged to control the drive of the steering motor 31.

[0053] The first reaction force control circuit 41A and the first steering control circuit 51A exchange information with each other via communication line L3. This information includes abnormal information from the first reaction force control circuit 41A, the first steering control circuit 51A, and the motor drive circuits 41B and 51B. The information also includes flag values ​​indicating various states. The first reaction force control circuit 41A and the first steering control circuit 51A operate cooperatively based on the information exchanged.

[0054] The second reaction force control circuit 42A and the second steering control circuit 52A exchange information with each other via communication line L4. This information includes abnormal information from the second reaction force control circuit 42A and the second steering control circuit 52A, or from the motor drive circuits 42B and 52B. The information also includes flag values ​​indicating various states. The second reaction force control circuit 42A and the second steering control circuit 52A operate cooperatively based on the information exchanged.

[0055] Example of comparing activation sequences

[0056] Next, a comparative example of the activation sequence of the reaction force control device 40 and the vehicle control device 60 will be described. The activation sequence is a series of processes executed with the vehicle power supply as a trigger. During periods when the vehicle power supply is off, the reaction force control device 40 and the vehicle control device 60 remain in a stopped state. For example, the switching on or off of the vehicle power supply also means the switching on or off of an activation switch located in the driver's seat. The activation switch operates when the drive source for driving the vehicle starts or stops, and is, for example, an ignition switch or a power switch.

[0057] First, a comparative example of the activation sequence of the vehicle control device 60 will be described. For example... Figure 3 As shown in the timeline, when the vehicle power is turned on (time point T1), the vehicle control unit 60 begins to execute the predetermined activation preparation. Activation preparation includes initial checks performed by the vehicle control unit 60 and the processing required to start the vehicle powertrain. After activation preparation is completed, the vehicle control unit 60 starts the powertrain (the main drive source for driving). When the powertrain start-up processing is completed (time point T2), the vehicle control unit 60 activates the preparation completion signal S1, regardless of the state of the reaction force control device 40.

[0058] The preparation completion signal S1 indicates whether the vehicle is ready to move, including whether the powertrain startup process is complete, and whether the vehicle is in a drivable state. The fact that the preparation completion signal S1 is open indicates that the vehicle is in a drivable state. The fact that the preparation completion signal S1 is closed indicates that the vehicle is not in a drivable state. The preparation completion signal S1 is sent as an electrical signal to the reaction force control device 40.

[0059] Next, a comparative example of the activation sequence of the reaction force control device 40 will be described. For example... Figure 3 As shown in the timeline, when the vehicle power is turned on (time point T1), the reaction force control device 40 is activated, sequentially performing initial checks, midpoint learning processing, and steering angle synchronization processing, before transitioning to an auxiliary start-up waiting state. The initial checks, midpoint learning processing, and steering angle synchronization processing are a series of preparatory processes required to begin executing the reaction force control that enables the reaction force motor 21 to generate steering reaction force.

[0060] The initial checks are initial tests performed triggered by the switching on of the vehicle's power supply, including, for example, hardware checks, central processing unit (CPU) initialization, and initialization of variables or flags.

[0061] The midpoint learning process is used to learn the steering neutral position of the steering wheel 11. The steering mechanism 10 has a stop mechanism that restricts the rotation of the steering wheel 11 to limit the steering angle of the steering wheel 11. For example, the stop mechanism limits the steering range of the steering wheel 11 to less than 360°. The reaction force control device 40 controls the reaction force motor 21 to operate the steering wheel 11 to a first operating end, and then reverses the operation to a second operating end. Afterwards, the reaction force control device 40 calculates the midpoint of the steering angle based on the rotation angle of the reaction force motor 21 at the end and beginning of the reverse operation of the steering wheel 11. The midpoint of the steering angle corresponds to the motor midpoint, which is the rotational position of the reaction force motor 21 when the steering wheel 11 is positioned in the steering neutral position. The reaction force control device 40 stores the midpoint of the steering angle or the motor midpoint as the steering neutral position of the steering wheel 11.

[0062] However, when a new battery is attached and the vehicle is powered on for the first time, the reaction force control unit 40 learns the steering wheel 11's neutral steering position. This is because the information related to the steering neutral position stored in the reaction force control unit 40 is lost due to, for example, the fact that power is not supplied to the reaction force control unit 40 when the battery is removed from the vehicle for battery replacement work.

[0063] The steering angle synchronization process is used to correct the rotational position of the steering wheel 11. When the rotational position of the steering wheel 11 is different from the rotational position corresponding to the steering position of the steering wheel 15, the reaction force control device 40 drives the reaction force motor 21 so that the rotational position of the steering wheel 11 is the rotational position corresponding to the steering position of the steering wheel 15.

[0064] The auxiliary start-up waiting state is a state where confirmation is received regarding the completion of the powertrain start-up process executed by the vehicle control unit 60 after the preparation process has been completed. The reaction force control unit 40 determines whether to transition from the auxiliary start-up waiting state to the normal control state based on the powertrain start-up state of the vehicle. When the vehicle control unit 60 does not activate the preparation completion signal S1, the reaction force control unit 40 determines that the execution of the vehicle's powertrain start-up process has not yet been completed and maintains the auxiliary start-up waiting state. When the vehicle control unit 60 activates the preparation completion signal S1, the reaction force control unit 40 determines that the execution of the vehicle's powertrain start-up process has been completed (time point T3), and the reaction force control unit 40 transitions from the auxiliary start-up waiting state to the normal control state. The normal control state is a state in which reaction force control is performed to generate steering reaction force in the reaction force motor 21. In the normal control state, the reaction force control unit 40 controls the drive of the reaction force motor 21 according to the steering state of the steering wheel 11.

[0065] exist Figure 3In the timeline diagram, as an example, the vehicle control unit 60 activates the preparation completion signal S1 during the midpoint learning process. However, when the vehicle is in a drivable state, the vehicle can drive regardless of the state of the reaction force control unit 40, even if the reaction force control unit 40 is in the middle of performing the preparation process. In this case, the following problem exists.

[0066] For example, when the vehicle starts moving but the reaction force control device 40 is in the middle of performing midpoint learning processing, the driver may find it difficult to steer the steering wheel 11 in the expected steering direction. This is because the steering wheel 11 is in an automatic rotation state during the midpoint learning process.

[0067] When the vehicle begins to move but the reaction force control device 40 is in the middle of performing rudder angle synchronization processing, the driver may find it difficult to steer the steering wheel 11 in the intended steering direction. This is because the steering wheel 11 is in an automatic rotation state during rudder angle synchronization processing. This is also because the rotational position of the steering wheel 11 during rudder angle synchronization processing differs from the original rotational position corresponding to the steering position of the steering wheel 15. Therefore, the reaction force control device 40 is configured to perform the following processing.

[0068] Startup license confirmation process

[0069] The reaction force control device 40 uses the connection of the vehicle power supply as a trigger to execute the start permission determination process. The start permission determination process determines whether the vehicle control device 60 is permitted to start the powertrain. According to the program stored in the reaction force control device 40, the start permission determination process is executed at predetermined control cycles.

[0070] like Figure 4 As shown in the flowchart, the reaction force control device 40 determines whether the preparation process for reaction force control is completed (step S101). The preparation process is the process of starting to perform the preparations required for reaction force control, and includes initial checks, midpoint learning processes, and rudder angle synchronization processes.

[0071] When it is determined that the preparation process is complete (step S101 is "Yes"), the reaction force control device 40 opens the start permission signal S2 (step S102) and ends the process. When it is determined that the preparation process is not complete (step S101 is "No"), the reaction force control device 40 closes the start permission signal S2 (step S103) and ends the process.

[0072] The start permission signal S2 indicates whether the vehicle control unit 60 is permitted to start the powertrain. Opening the start permission signal S2 indicates that the vehicle control unit 60 is permitted to start the powertrain. Closing the start permission signal S2 indicates that the vehicle control unit 60 is not permitted to start the powertrain. The start permission signal S2 is sent to the vehicle control unit 60 as an electrical signal.

[0073] First mode of activation sequence

[0074] Next, the first mode of activation sequence will be described. For example... Figure 5 As shown in the timeline, when the vehicle power is turned on (time point T1), the reaction force control device 40 is activated to sequentially perform initial checks, midpoint learning processing, and rudder angle synchronization processing. When the preparation process, including initial checks, midpoint learning processing, and rudder angle synchronization processing, is completed, the reaction force control device 40 transitions to an auxiliary start-up waiting state and activates the start-up permission signal S2. The auxiliary start-up waiting state indicates that the reaction force control is ready and can transition to the normal control state.

[0075] When the vehicle power is turned on (time point T1), the vehicle control unit 60 begins to perform the predetermined activation preparation. After the activation preparation is completed (time point T4), the vehicle control unit 60 transitions to the start permission waiting state. The start permission waiting state is the state of waiting for the reaction force control device 40 to allow the powertrain to start, that is, the state of waiting for the start permission signal S2 to be opened.

[0076] When the vehicle control unit 60 detects that the start permission signal S2 has been opened while the start permission waiting state is in effect (at time T5), it starts the vehicle's powertrain. When the powertrain start process is completed, the vehicle control unit 60 opens the preparation completion signal S1.

[0077] When the signal S1 indicating completion of the assisted start waiting state is detected (time point T6), the reaction force control device 40 switches to the normal control state (time point T8). The reaction force control device 40 controls the drive of the reaction force motor 21 according to the steering state of the steering wheel 11.

[0078] In this way, when the reaction force control device 40 has not completed its preparation for reaction force control, even if the vehicle control device 60 has completed its activation preparation, the vehicle control device 60 will wait until the preparation is complete before starting the vehicle's powertrain. For this reason, the vehicle can only be driven after the reaction force control device 40 has transitioned to an auxiliary start-up waiting state where reaction force control can be performed. Therefore, even if the reaction force control device 40 is in the middle of performing preparation, the vehicle is prevented from being in a drivable state. Furthermore, the vehicle can be started and driven in a state that is safer for the driver, i.e., when the vehicle can steer in the direction the driver intends.

[0079] Anti-impersonation measures

[0080] In the first mode of the activation sequence, there is a problem: a third party impersonating the reaction force control device 40 or the vehicle control device 60 may forge the activation of the start authorization signal S2 by the reaction force control device 40 or the activation of the preparation completion signal S1 by the vehicle control device 60. In this case, the vehicle may transition to a drivable state before the reaction force control device 40 transitions to an auxiliary start-waiting state where reaction force control can be performed. Therefore, the reaction force control device 40 is configured to perform the following process.

[0081] Determine the processing of vehicle stop requests

[0082] The reaction force control device 40 uses the connection of the vehicle's power supply as a trigger to perform a stop request determination process on the vehicle. The stop request determination process determines whether it is necessary to request the vehicle control device 60 to stop the starting of the vehicle's powertrain. According to the program stored in the reaction force control device 40, the stop request determination process is executed at predetermined control cycles.

[0083] like Figure 6 As shown in the flowchart, the reaction force control device 40 determines whether it is necessary to request the vehicle control device 60 to stop the starting of the vehicle's powertrain (step S201).

[0084] The reaction force control device 40 determines whether it is necessary to request the vehicle control device 60 to stop the starting of the vehicle's powertrain based on whether predetermined conditions are met. The determination conditions are used to determine whether the reaction force control device 40's opening of the start permission signal S2 or the vehicle control device 60's opening of the preparation completion signal S1 has been forged.

[0085] The determining conditions include, for example, the following two conditions A1 and A2. When both conditions A1 and A2 are met, the reaction force control device 40 determines that it is necessary to request the vehicle control device 60 to stop the starting of the vehicle's powertrain. Furthermore, when either condition A1 or A2 is not met, the reaction force control device 40 determines that it is not necessary to request the vehicle control device 60 to stop the starting of the vehicle's powertrain.

[0086] A1: Start permission signal S2 is closed. A2: Readiness complete signal S1 is open. The determining conditions are set based on the following viewpoint. That is, for example, when the vehicle control device 60 opens the readiness complete signal S1 but the reaction force control device 40 does not open the start permission signal S2, a third party impersonating the reaction force control device 40 may forge the opening of the start permission signal S2.

[0087] When it is determined that the vehicle control device 60 needs to be requested to stop the start of the vehicle's powertrain (step S201 is "Yes"), the reaction force control device 40 opens the vehicle stop request signal S3 (step S202) and ends the process.

[0088] When it is determined that there is no need to request the vehicle control device 60 to stop the start of the vehicle's powertrain (step S201 is "No"), the reaction force control device 40 shuts off the vehicle stop request signal S3 (step S203) and ends the process.

[0089] The vehicle stop request signal S3 indicates whether the vehicle control unit 60 is requested to stop the operation of the powertrain. The fact that the vehicle stop request signal S3 is on indicates that the vehicle control unit 60 has been requested to stop the operation of the powertrain. The fact that the vehicle stop request signal S3 is off indicates that the vehicle control unit 60 has not been requested to stop the operation of the powertrain. The vehicle stop request signal S3 is sent to the vehicle control unit 60 as an electrical signal.

[0090] Second mode of activation sequence

[0091] Next, the second mode of the activation sequence will be described. As an example, the case where a fake start permission signal S2 is opened during the midpoint learning process, which is part of the preparation process of the reaction force control device 40, is investigated. Furthermore, preparation for activating the vehicle control device 60 is completed before the midpoint learning process of the reaction force control device 40 is completed.

[0092] like Figure 7As shown in the timeline, when the vehicle power is turned on (time point T1), the reaction force control device 40 is activated to begin performing an initial check. After the initial check is completed normally, the reaction force control device 40 begins performing a midpoint learning process. For example, when a fake start permission signal S2 is opened during the midpoint learning process (time point T7), the vehicle control device 60 recognizes that the start permission signal S2 has been opened, for example, at the activation preparation completion time point. Therefore, after activation preparation is completed, the vehicle control device 60 immediately starts the vehicle's powertrain without transitioning to a start permission waiting state. When the powertrain starting process is completed, the vehicle control device 60 opens the preparation completion signal S1 (time point T8).

[0093] When it is detected that the preparation completion signal S1 is turned on but midpoint learning processing is in progress, the reaction force control device 40 turns on the vehicle stop request signal S3 (at time T9). This is because a third party impersonating the reaction force control device 40 may forge the opening of the start permission signal S2.

[0094] After the vehicle powertrain is started, when the vehicle stop request signal S3 is detected, the vehicle control unit 60 executes a predetermined process. This predetermined process is, for example, a process for stopping the operation of the powertrain. Therefore, the vehicle is in an inoperable state. Furthermore, it prevents the vehicle from remaining in a drivable state due to fraudulent behavior (e.g., impersonation) even when the reaction force control unit 40 is in the middle of executing a preparation process.

[0095] Effects of this implementation method

[0096] Therefore, according to this embodiment, the following effects can be obtained: (1) When the vehicle power is turned on, the reaction force control device 40 requests the vehicle control device 60 to stop the vehicle's movement when exchanging information with the vehicle control device 60 in a manner that does not follow a predetermined pattern. The information exchange includes, for example, the vehicle control device 60's recognition of the opening of the start permission signal S2 and the reaction force control device 40's recognition of the opening of the preparation completion signal S1. The predetermined pattern includes, for example, the reaction force control device 40 opening the start permission signal S2, and then the vehicle control device 60 opening the preparation completion signal S1 in response to the opening of the start permission signal S2. When this configuration is adopted, there is a possibility that the information exchanged between the reaction force control device 40 and the vehicle control device 60 may be forged due to some kind of fraudulent activity. In this respect, according to this embodiment, when the reaction force control device 40 and the vehicle control device 60 exchange information in a manner that does not follow a predetermined pattern, the vehicle's movement can be suppressed. Therefore, the crime prevention performance is further improved.

[0097] (2) When the preparation process for reaction force control is completed, the reaction force control device 40 allows the vehicle control device 60 to transition the vehicle to a drivable state. The transition to a drivable state is, for example, the starting of the vehicle powertrain. Permission to the vehicle control device 60 is granted, for example, by the reaction force control device 40 opening the start permission signal S2. The vehicle control device 60 waits until the reaction force control device 40 permits the vehicle to transition to a drivable state before transitioning the vehicle to that state. For this reason, the vehicle can only be driven after the preparation process of the reaction force control device 40 is completed. Therefore, the driver can begin driving the vehicle in a safer state.

[0098] (3) When it is detected that the vehicle is in a drivable state but the reaction force control device 40 does not allow the vehicle control device 60 to switch the vehicle to a drivable state, permission to the vehicle control device 60 may be forged due to fraudulent behavior (e.g., impersonation). Forgery of permission to the vehicle control device 60 may be, for example, forgery of opening the start permission signal S2. The fact that the vehicle is in a drivable state can be identified, for example, by opening the preparation completion signal S1. According to this embodiment, when permission to the vehicle control device 60 may be forged, the vehicle control device 60 is requested to stop the vehicle's movement. For example, the vehicle control device 40 requests to prohibit the vehicle from moving by opening the vehicle stop request signal S3. By stopping the vehicle in response to the request from the reaction force control device 40, the crime prevention performance is improved.

[0099] (4) The preparation process of the reaction force control device 40 includes midpoint learning processing and steering angle synchronization processing. For example, when the vehicle starts moving but the steering control device is in the middle of performing midpoint learning processing or steering angle synchronization processing, the driver may find it difficult to turn the steering wheel 11 in the expected steering direction. This is because the steering wheel 11 rotates automatically during midpoint learning processing or during steering angle synchronization processing. In this respect, according to this embodiment, when the preparation process for reaction force control is completed, the reaction force control device 40 allows the vehicle control device 60 to change the vehicle to a drivable state. For this reason, the vehicle can only be driven after the preparation process of the reaction force control device 40 is completed. Therefore, the driver can start driving the vehicle in a safer state. There is no discomfort for the driver.

[0100] (5) The vehicle control device 60 controls the starting of the powertrain, which includes the drive source for driving the vehicle. Therefore, when the vehicle control device 60 controls the starting of the vehicle's powertrain, the vehicle can be brought into a drivable state.

[0101] Other implementation methods

[0102] This implementation can achieve the following changes: The preparation completion signal S1, the start permission signal S2, and the vehicle stop request signal S3 can be flags.

[0103] In this embodiment, the reaction force motor 21 and the steering motor 31 have two winding groups, but may have only one winding group. In this case, the reaction force control device 40 may have only one of the first system circuit 41 or the second system circuit 42. Furthermore, in this case, the steering control device 50 may have only one of the first system circuit 51 or the second system circuit 52. The first reaction force control circuit 41A or the second reaction force control circuit 42A corresponds to the reaction force control circuit. The first steering control circuit 51A or the second steering control circuit 52A corresponds to the steering control circuit.

Claims

1. A steering control device characterized by A control circuit configured to control driving of a reaction force motor (21) that generates a steering reaction force applied to a steering wheel (11) that is separated from power transmission of a steering wheel (15) of a vehicle, wherein the control circuit requests a vehicle control device (60) that controls running of the vehicle to stop the running of the vehicle when information is exchanged with the vehicle control device (60) in a manner that does not follow a predetermined pattern when the vehicle power source is turned on.

2. The steering control device according to claim 1, characterized by When execution of a preparation process performed as a trigger of the turning on of the vehicle power source is completed, the control circuit allows the vehicle control device (60) to transition the vehicle to a runnable state and to a normal control state in which reaction force control that causes the reaction force motor (21) to generate a steering reaction force is executed when the vehicle is recognized as being in the runnable state via the vehicle control device (60).

3. The steering control device according to claim 2, characterized by When the vehicle is recognized as being in the runnable state via the vehicle control device (60), the control circuit requests the vehicle control device (60) to stop the running of the vehicle even if the vehicle control device is not allowed to transition the vehicle to the runnable state.

4. The turning control device according to claim 2 or 3, characterized by The preparation process includes: a midpoint learning process of operating the steering wheel (11) to a first operation end and then reversely operating the steering wheel (11) to a second operation end to learn a midpoint of a steering neutral position of the steering wheel (11) on a premise that a steering range of the steering wheel (11) is limited to less than 360°; and a rudder angle synchronization process of correcting a rotation position of the steering wheel (11) so that the rotation position of the steering wheel (11) is a rotation position corresponding to a steering position of the steering wheel (15).

5. The turning control device according to any one of claims 1 to 3, characterized by, The vehicle control device (60) controls activation of a powertrain including a drive source for running of the vehicle.

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