Steering control device

Abstract

To provide a steering control device which can enhance the crime prevention property.SOLUTION: A reaction force control device 40 permits a vehicle control device 60 to shift a vehicle into a state where the vehicle can travel when execution of preparation processing executed with the turn-on of a vehicle power source as a trigger is complete. Then, the reaction force control device 40 shifts to a normal control state being the state of executing reaction force control of generating the steering reaction force in a reaction force motor when it is recognized that the vehicle can travel via the vehicle control device 60. The reaction force control device 40 requests the vehicle control device to stop the travel of the vehicle (time T9) when it is recognized that the vehicle can travel via the vehicle control device 60 (time T8) regardless of such a state that the vehicle control device 60 is not permitted to shift the vehicle into the state where the vehicle can travel.SELECTED DRAWING: Figure 7

Description

Technical Field

[0001] The present invention relates to a steering control device.

Background Art

[0002] Conventionally, there is a so-called steer-by-wire type steering device in which the power transmission between the steering wheel and the steered wheels is separated (see, for example, Patent Document 1). This steering device includes a reaction force mechanism having a reaction force motor that is a source of the steering reaction force applied to the steering shaft, and a steering mechanism having a steering motor that is a source of the steering force for steering the steered wheels. When the vehicle is running, the control device of the steering device generates a steering reaction force through power supply control for the reaction force motor and steers the steered wheels through power supply control for the steering motor.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] Higher security performance is required for vehicles. It is also required to enhance the security performance of the steering device mounted on the vehicle.

Means for Solving the Problems

[0005] The steering control device capable of solving the above problems has a control circuit that controls the drive of a reaction force motor that generates a steering reaction force applied to a steering wheel in which the power transmission to the steered wheels of the vehicle is separated. When the vehicle power supply is turned on, the control circuit requests the vehicle control device to stop the running of the vehicle when information exchange not following a defined pattern occurs between the control circuit and the vehicle control device that controls the running of the vehicle.

[0006] There is a concern that information exchanged between the steering control device and the vehicle control device may be falsified through some kind of fraudulent activity. In this regard, according to the above configuration, when information is exchanged between the control circuit and the vehicle control device that does not follow a predetermined pattern, the vehicle can be prevented from traveling. This improves crime prevention.

[0007] In the above-mentioned steering control device, when the execution of the preparatory processing, which is executed in response to the vehicle power being turned on, is completed, the control circuit may allow the vehicle control device to transition the vehicle to a state in which it can be driven, and when it is recognized via the vehicle control device that the vehicle is in a state in which it can be driven, the control circuit may transition to a normal control state in which reaction force control is executed to generate a steering reaction force in the reaction force motor.

[0008] According to the above configuration, when the preparation process for the reaction force control is completed, the steering control device permits the vehicle control device to transition the vehicle to a state in which the vehicle can be driven. That is, the vehicle control device transitions the vehicle to a state in which the vehicle can be driven after the steering control device permits the transition of the vehicle to a state in which the vehicle can be driven. Therefore, the vehicle can only travel after the preparation process for the steering control device is completed. Therefore, the vehicle can start traveling in a safer state for the driver.

[0009] In the above-mentioned steering control device, when the control circuit recognizes via the vehicle control device that the vehicle is in a state in which it can be driven, even though the control circuit has not permitted the vehicle control device to transition the vehicle to a state in which it can be driven, the control circuit may request the vehicle control device to stop the driving of the vehicle.

[0010] Even though the steering control device does not permit the vehicle control device to transition the vehicle to a drivable state, when it is recognized that the vehicle is in a drivable state, there is a risk that the permission for the vehicle control device has been forged by an illegal act such as impersonation. In this regard, according to the above configuration, when there is a risk that the permission for the vehicle control device has been forged, the vehicle control device is requested to stop the running of the vehicle. By the vehicle control device stopping the running of the vehicle in response to a request from the steering control device, the security is enhanced.

[0011] In the above steering control device, the preparation process may include a midpoint learning process of learning the steering neutral position of the steering wheel by operating the steering wheel to a first operating end and then reversely operating it to a second operating end on the premise that the steering range of the steering wheel is restricted to less than 360°, and a rudder angle synchronization process of correcting the rotational position of the steering wheel so that the rotational position of the steering wheel becomes a rotational position corresponding to the steering position of the steered wheels.

[0012] For example, if the vehicle starts running even though the steering control device is in the middle of executing the midpoint learning process or the rudder angle synchronization process, the driver may have difficulty steering the steering wheel in the intended steering direction. This is because the steering wheel is in a state of automatic rotation during the execution of the midpoint learning process or the rudder angle synchronization process. In this regard, according to the above configuration, when the preparation process of the reaction force control is completed, the steering control device permits the vehicle control device to transition the vehicle to a drivable state. Therefore, the vehicle can only run after the preparation process of the steering control device is completed. Accordingly, the vehicle can start running in a safer state for the driver and does not give the driver a sense of discomfort.

[0013] In the above steering control device, the vehicle control device may control the start of a power train including a driving source for running the vehicle. According to the above configuration, by controlling the start of the power train of the vehicle through the vehicle control device, the vehicle can be transitioned to a state where it can travel.

Effect of the Invention

[0014] According to the steering control device of the present invention, the crime prevention performance can be further enhanced.

Brief Description of the Drawings

[0015]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Mode for Carrying Out the Invention

[0016] Hereinafter, a first embodiment in which the steering control device is embodied in a steer-by-wire type steering device will be described. As shown in Fig. 1, the steering device 10 of the vehicle has a steering shaft 12 connected to the steering wheel 11. Further, the steering device 10 has a steering shaft 13 extending along the vehicle width direction (the left - right direction in Fig. 1). At both ends of the steering shaft 13, steering wheels 15 are respectively connected via tie rods 14. When the steering shaft 13 moves linearly, the steering angle θw of the steering wheels 15 is changed. The steering shaft 12 and the steering shaft 13 constitute the steering mechanism of the vehicle. Note that in Fig. 1, only one - side steering wheel 15 is illustrated.

[0017] The steering device 10 has a reaction force motor 21 and a speed reduction mechanism 22. The reaction force motor 21 is a source of the steering reaction force. The steering reaction force refers to the force acting in the direction opposite to the operation direction of the steering wheel 11 by the driver. The rotating shaft of the reaction force motor 21 is connected to the steering shaft 12 via the speed reduction mechanism 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, it is possible to give an appropriate sense of resistance to the driver.

[0018] The reaction force motor 21 is, for example, a three - phase brushless motor. The reaction force 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 electrical characteristics of the first - system winding group N11 and the second - system winding group N12 are equivalent.

[0019] The steering device 10 has a steering motor 31 and a speed reduction mechanism 32. The steering motor 31 is a source of the steering force. The steering force refers to the power for steering the steering wheels 15. The rotating shaft of the steering motor 31 is connected to a pinion shaft 33 via the speed reduction mechanism 32. The pinion teeth 33a of the pinion shaft 33 are meshed with the rack teeth 13b of the steering shaft 13. The torque of the steering motor 31 is applied to the steering shaft 13 as the steering force via the pinion shaft 33. In response to the rotation of the steering motor 31, the steering shaft 13 moves along the vehicle width direction.

[0020] 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 electrical characteristics of the first system winding group N21 and the second system winding group N22 are equivalent.

[0021] The steering device 10 has 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 executes reaction force control for generating a steering reaction force corresponding to the steering torque Th in the reaction force motor 21. The reaction force control device 40 calculates a target steering reaction force based on the steering torque Th detected through the torque sensor 23. The torque sensor 23 is provided on the steering shaft 12. The reaction force control device 40 controls the power supply to the reaction force motor 21 so as to match the actual steering reaction force applied to the steering shaft 12 with the target steering reaction force. The reaction force control device 40 independently controls the power supply to the two system winding groups in the reaction force motor 21 for each system.

[0022] 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 first system winding group N11 in the reaction force motor 21 according to the steering torque Th detected through the torque sensor 23. The second system circuit 42 controls the power supply to the second system winding group N12 in the reaction force motor 21 according to the steering torque Th detected through the torque sensor 23.

[0023] The reaction force control device 40 and the in-vehicle vehicle control device 60 are interconnected via an in-vehicle network 61. The in-vehicle network 61 is, for example, a CAN (Controller Area Network). The reaction force control device 40 and the in-vehicle vehicle control device 60 exchange information with each other via the in-vehicle network 61. The vehicle control device 60 controls the running of the vehicle. Specifically, the vehicle control device 60 controls, for example, the power train of the vehicle. The power train includes a driving source for vehicle running and a power transmission mechanism. The driving source for vehicle running includes, for example, an engine or a motor. The power transmission mechanism is a mechanism for transmitting the power generated by the driving source for vehicle running to the drive wheels. The reaction force control device 40 controls the driving of the reaction force motor 21 based on the information exchanged with the vehicle control device 60.

[0024] The steering device 10 has a steering control device 50. The steering control device 50 controls the driving of the steering motor 31 which is the control target. The steering control device 50 executes a steering control for generating a steering force for steering the steered wheels 15 in accordance with the steering state in the steering motor 31. The steering control device 50 takes in the steering angle θs detected through the steering angle sensor 24 and the stroke Xw of the steering shaft 13 detected through the stroke sensor 34. The stroke Xw is a displacement amount based on the neutral position of the steering shaft 13 and is a state variable in which the steering angle θw is reflected. The steering angle sensor 24 is provided between the torque sensor 23 of the steering shaft 12 and the speed reduction mechanism 22. The stroke sensor 34 is provided in the vicinity of the steering shaft 13.

[0025] The steering control device 50 calculates the target steering angle of the steered wheels 15 based on the steering angle θs detected through the steering angle sensor 24. The steering control device 50 calculates the steering angle θw based on the stroke Xw of the steering shaft 13 detected through the stroke sensor 34. The steering control device 50 controls the power supply to the steering motor 31 so as to match the steering angle θw calculated based on the stroke Xw with the target steering angle. The steering control device 50 independently controls the power supply to the two winding groups in the steering motor 31 for each system.

[0026] The steering control device 50 has a first system circuit 51 and a second system circuit 52. The first system circuit 51 controls the power supply to the winding group N21 of the first system in the steering motor 31 based on the steering angle θs detected through the steering angle sensor 24 and the stroke Xw of the steering shaft 13 detected through the stroke sensor 34. The second system circuit 52 controls the power supply to the winding group N22 of the second system in the steering motor 31 based on the steering angle θs detected through the steering angle sensor 24 and the stroke Xw of the steering shaft 13 detected through the stroke sensor 34.

[0027] Note that a so-called mechatronic reaction actuator may be configured by integrally providing the reaction control device 40 and the reaction motor 21. Further, a so-called mechatronic steering actuator may be configured by integrally providing the steering control device 50 and the steering motor 31. The reaction control device 40 and the steering control device 50 constitute a steering control device.

[0028] <Reaction control device> Next, the configuration of the reaction control device will be described in detail. As shown in FIG. 2, the reaction control device 40 has a first system circuit 41 and a second system circuit 42. The first system circuit 41 has a first reaction control circuit 41A and a motor drive circuit 41B. The second system circuit 42 has a second reaction control circuit 42A and a motor drive circuit 42B.

[0029] The first reaction force control circuit 41A is constituted by a processing circuit including: 1. one or more processors operating according to a computer program (software); 2. one or more dedicated hardware circuits such as an application specific integrated circuit (ASIC) that executes at least some of various processes; 3. a combination thereof. The processor includes a CPU (central processing unit). The processor also includes memories such as a RAM (random-access memory) and a ROM (read-only memory). The memory stores program codes or instructions configured to cause the CPU to execute processes. The memory, that is, the non-transitory computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer.

[0030] The first reaction force control circuit 41A calculates a target steering reaction force to be generated in the reaction force motor 21 based on the steering torque Th detected through the torque sensor 23, and calculates a first current command value for the first winding group N11 according to the value of the calculated target steering reaction force. However, the first current command value is set to a value that is half (50%) of the amount of current (100%) required to generate the target steering reaction force in the reaction force motor 21. The first reaction force control circuit 41A generates a drive signal (PWM signal) for the motor drive circuit 41B by executing current feedback control to make the value of the actual current supplied to the first winding group N11 follow the first current command value.

[0031] The motor drive circuit 41B is a PWM inverter in which three legs corresponding to each of the three phases (U, V, W) are connected in parallel, with switching elements such as two field-effect transistors (FETs) connected in series as a leg that is the basic unit. The motor drive circuit 41B converts the DC power supplied from the battery into three-phase AC power by switching the switching elements of each phase based on the drive signal generated by the first reaction force control circuit 41A. The three-phase AC power generated by the motor drive circuit 41B is supplied to the first winding group N11 of the reaction force motor 21 via the power supply path of each phase consisting of a bus bar or a cable or the like. Thereby, the first winding group N11 generates torque corresponding to the first current command value.

[0032] The second reaction force control circuit 42A basically has 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 through the torque sensor 23, and calculates the second current command value for the second winding group N12 according to the value of the calculated target steering reaction force. However, the second current command value is set to a value that is half (50%) of the amount of current required to generate the target steering reaction force in the reaction force motor 21. The second reaction force control circuit 42A generates a drive signal for the motor drive circuit 42B by performing current feedback control that causes the value of the actual current supplied to the second winding group N12 to follow the second current command value.

[0033] The motor drive circuit 42B basically has the same configuration as the motor drive circuit 41B. The motor drive circuit 42B converts the DC power supplied from the battery into three-phase AC power based on the drive signal generated by the second reaction force control circuit 42A. The three-phase AC power generated by the motor drive circuit 42B is supplied to the second winding group N12 of the reaction force motor 21 via the power supply path for each phase consisting of a bus bar or a cable or the like. As a result, the second winding group N12 generates torque corresponding to the second current command value. The reaction force motor 21 generates a total torque of the torque generated by the first winding group N11 and the torque generated by the second winding group N12.

[0034] Note that 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. In this case, for example, the first system circuit 41 may function as a master and the second system circuit 42 may function as a slave. Also, depending on the product specifications, the first system circuit 41 and the second system circuit 42 may have an equal relationship.

[0035] <Steering control device> Next, the configuration of the steering control device 50 will be described in detail. As shown in FIG. 2, 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.

[0036] The first steering control circuit 51A basically has the same configuration as the first reaction force control circuit 41A. The first steering control circuit 51A calculates the target steering angle of the steering wheel 15 based on the steering angle θs detected through the steering angle sensor 24. The steering control device 50 calculates the steering angle θw based on the stroke Xw of the steering shaft 13 detected through the stroke sensor 34. The first steering control circuit 51A calculates the target steering force to be generated in the steering motor 31 by executing angle feedback control to make the steering angle θw calculated based on the stroke Xw follow the target steering angle, and calculates a third current command value for the first winding group N21 of the steering motor 31 according to the value of the calculated target steering force. However, the third current command value is set to a value that is half (50%) of the amount of current required to generate the target steering force in the steering motor 31. The first steering control circuit 51A generates a drive signal for the motor drive circuit 51B by executing current feedback control to make the value of the actual current supplied to the first winding group N21 follow the third current command value.

[0037] The motor drive circuit 51B basically has the same configuration as the motor drive circuit 41B. The motor drive circuit 51B converts the DC power supplied from the battery into three-phase AC power based on the drive signal generated by the first steering control circuit 51A. The three-phase AC power generated by the motor drive circuit 42B is supplied to the first winding group N21 of the steering motor 31 through the power supply path of each phase consisting of a bus bar or a cable. As a result, the first winding group N21 generates torque according to the third current command value.

[0038] The second steering control circuit 52A basically has the same configuration as the first reaction force control circuit 41A. The second steering control circuit 52A calculates the target steering angle of the steering wheel 15 based on the steering angle θs detected through the steering angle sensor 24. The steering control device 50 calculates the steering angle θw based on the stroke Xw of the steering shaft 13 detected through the stroke sensor 34. The second steering control circuit 52A calculates the target steering force to be generated in the steering motor 31 by executing angle feedback control to make the steering angle θw calculated based on the stroke Xw follow the target steering angle, and calculates the fourth current command value for the second winding group N22 of the steering motor 31 according to the value of the calculated target steering force. However, the fourth current command value is set to half (50%) of the amount of current required to generate the target steering force in the steering motor 31. The second steering control circuit 52A generates a drive signal for the motor drive circuit 52B by executing current feedback control to make the value of the actual current supplied to the second winding group N22 follow the fourth current command value.

[0039] The motor drive circuit 52B basically has the same configuration as the motor drive circuit 41B. The motor drive circuit 51B converts the DC power supplied from the battery into three-phase AC power based on the drive signal generated by the second steering control circuit 52A. The three-phase AC power generated by the motor drive circuit 52B is supplied to the second winding group N22 of the steering motor 31 through the power supply path of each phase composed of a bus bar or a cable or the like. Thereby, the second winding group N22 generates torque corresponding to the fourth current command value. The steering motor 31 generates a total torque of the torque generated by the first winding group N21 and the torque generated by the second winding group N22.

[0040] Note that 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. In this case, for example, the first system circuit 51 may function as the master and the second system circuit 52 may function as the slave. Also, depending on the product specifications, the first system circuit 51 and the second system circuit 52 may have an equal relationship.

[0041] <Communication path> Next, the communication paths inside 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.

[0042] As shown in FIG. 2, the first reaction force control circuit 41A and the second reaction force control circuit 42A exchange information with each other via the communication line L1. The information includes abnormality information of the first reaction force control circuit 41A, the second reaction force control circuit 42A, or the motor drive circuits 41B and 42B. Further, the information includes the values of flags indicating various states. The first reaction force control circuit 41A and the second reaction force control circuit 42A cooperate to control the drive of the reaction force motor 21 based on the information exchanged between them.

[0043] The first steering control circuit 51A and the second steering control circuit 52A exchange information with each other via the communication line L2. The information includes abnormality information of the first steering control circuit 51A, the second steering control circuit 52A, or the motor drive circuits 51B and 52B. Further, the information includes the values of flags indicating various states. The first steering control circuit 51A and the second steering control circuit 52A cooperate to control the drive of the steering motor 31 based on the information exchanged between them.

[0044] The first reaction force control circuit 41A and the first steering control circuit 51A exchange information with each other via the communication line L3. The information includes abnormality information of the first reaction force control circuit 41A, the first steering control circuit 51A, and the motor drive circuits 41B and 51B. Further, the information includes the values of flags indicating various states. The first reaction force control circuit 41A and the first steering control circuit 51A operate in cooperation based on the information exchanged between them.

[0045] The second reaction force control circuit 42A and the second turning control circuit 52A exchange information with each other via the communication line L4. The information includes abnormality information of the second reaction force control circuit 42A, the second turning control circuit 52A, or the motor drive circuits 42B, 52B. The information also includes flag values ​​indicating various states. The second reaction force control circuit 42A and the second turning control circuit 52A operate in cooperation with each other based on the information exchanged between them.

[0046] <Comparison example of startup sequence> Next, a comparative example of the start-up sequence of the reaction force control device 40 and the vehicle control device 60 will be described. The start-up sequence is a series of processes that are executed when the vehicle power supply is turned on. While the vehicle power supply is turned off, the reaction force control device 40 and the vehicle control device 60 are maintained in a stopped state. Turning the vehicle power supply on or off also means, for example, turning on or off a start switch provided in the driver's seat. The start-up switch is operated when starting or stopping the driving source for running the vehicle, and is, for example, an ignition switch or a power switch.

[0047] First, a comparative example of the start-up sequence of the vehicle control device 60 will be described. As shown in the time chart of FIG. 3, when the vehicle power supply is turned on (time T1), the vehicle control device 60 starts executing a defined startup preparation. The startup preparation includes an initial check of the vehicle control device 60 and processing required to start the vehicle's powertrain. After the startup preparation is completed, the vehicle control device 60 starts the powertrain (mainly the driving source for traveling). When the startup processing of the powertrain is completed, the vehicle control device 60 turns on the preparation completion signal S1 (time T2). The vehicle control device 60 turns on the preparation completion signal S1 regardless of the state of the reaction force control device 40.

[0048] The preparation completion signal S1 is information indicating whether the vehicle is ready to run, including the completion of the start-up process of the power train, and has reached a state where the vehicle can run. When the preparation completion signal S1 is on, it indicates that the vehicle has reached a state where it can run. When the preparation completion signal S1 is off, it indicates that the vehicle has not reached a state where it can run. The preparation completion signal S1 is transmitted to the reaction force control device 40 as an electrical signal.

[0049] Next, a comparative example of the start-up sequence of the reaction force control device 40 will be described. As shown in the time chart of FIG. 3, when the vehicle power supply is turned on (time T1), the reaction force control device 40 starts up and sequentially executes an initial check, a midpoint learning process, and a steering angle synchronization process, and eventually transitions to an assist start waiting state. The initial check, the midpoint learning process, and the steering angle synchronization process are a series of preparatory processes required to start executing reaction force control for generating a steering reaction force in the reaction force motor 21.

[0050] The initial check is an initial inspection executed upon the vehicle power supply being turned on, and includes, for example, a hardware check, initialization of the CPU (Central Processing Unit), and initialization of variables or flags.

[0051] The neutral point learning process is a process for learning the steering neutral position of the steering wheel 11. The steering device 10 has a stopper mechanism that restricts the rotation of the steering wheel 11 in order to provide a limit to the steering angle of the steering wheel 11. The stopper mechanism restricts, for example, the steering range of the steering wheel 11 to less than 360°. The reaction force control device 40 operates the steering wheel 11 to the first operating end and then reverses it to the second operating end through the control of the reaction force motor 21. After that, the reaction force control device 40 calculates the midpoint of the steering angle based on the rotation angles of the reaction force motor 21 at the start and end points 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 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.

[0052] However, the reaction force control device 40 learns the steering neutral position of the steering wheel 11 when the vehicle power is turned on for the first time after a new battery is newly installed. This is because, for example, when the battery is removed from the vehicle due to battery replacement work, the power supply to the reaction force control device 40 is cut off, resulting in the loss of information regarding the steering neutral position stored in the reaction force control device 40.

[0053] The steering angle synchronization process is a process for correcting 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 steered wheels 15, the reaction force control device 40 drives the reaction force motor 21 so that the rotational position of the steering wheel 11 becomes the rotational position corresponding to the steering position of the steered wheels 15.

[0054] The assist start waiting state is a state in which, after the execution of the preparation process is completed, it waits for the completion of the start process of the power train by the vehicle control device 60 to be confirmed. The reaction force control device 40 determines whether it is possible to transition from the assist start waiting state to the normal control state according to the start state of the power train of the vehicle. When the preparation completion signal S1 is not turned on by the vehicle control device 60, the reaction force control device 40 determines that the start process of the power train of the vehicle has not been completed, and maintains the assist start waiting state. When the preparation completion signal S1 is turned on by the vehicle control device 60, the reaction force control device 40 determines that the start process of the power train of the vehicle has been completed (time T3), and transitions from the assist start waiting state to the normal control state. The normal control state is a state in which reaction force control for generating a steering reaction force in the reaction force motor 21 is executed. When in the normal control state, 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.

[0055] In the time chart of FIG. 3, as an example, the vehicle control device 60 turns on the preparation completion signal S1 during the execution of the midpoint learning process. However, when the vehicle becomes capable of running regardless of the state of the reaction force control device 40 in this way, it becomes possible to run the vehicle even though the reaction force control device 40 is in the middle of executing the preparation process. In this case, the following concerns arise.

[0056] For example, when the vehicle starts running even though the reaction force control device 40 is in the middle of executing the midpoint learning process, the driver may have difficulty steering the steering wheel 11 in the intended steering direction. This is because the steering wheel 11 is in a state of automatic rotation during the execution of the midpoint learning process.

[0057] Also, even when the vehicle starts while the reaction force control device 40 is in the middle of executing the rudder angle synchronization process, the driver may have difficulty steering the steering wheel 11 in the intended steering direction. This is because the steering wheel 11 is in a state of automatic rotation during the execution of the rudder angle synchronization process. Also, during the execution of the rudder angle synchronization process, the rotation position of the steering wheel 11 is different from the original rotation position corresponding to the steering position of the steered wheels 15. Therefore, the reaction force control device 40 is configured to execute the following process.

[0058] <Starting Permission Determination Process> When the vehicle power supply is turned on, the reaction force control device 40 executes a starting permission determination process. The starting permission determination process is a process for determining whether to permit the start of the power train to the vehicle control device 60. The starting permission determination process is executed at a predetermined control cycle according to a program stored in the reaction force control device 40.

[0059] As shown in the flowchart of FIG. 4, the reaction force control device 40 determines whether the preparation process for reaction force control has been completed (step S101). The preparation process is a process for preparation required to start executing reaction force control, and includes an initial check, a midpoint learning process, and a rudder angle synchronization process.

[0060] When it is determined that the preparation process has been completed (YES in step S101), the reaction force control device 40 turns on the starting permission signal S2 (step S102) and ends the process. When it is determined that the preparation process has not been completed (NO in step S101), the reaction force control device 40 turns off the starting permission signal S2 (step S103) and ends the process.

[0061] The start permission signal S2 is information indicating whether to permit the start of the power train to the vehicle control device 60. That the start permission signal S2 is on indicates that the vehicle control device 60 permits the start of the power train. That the start permission signal S2 is off indicates that the vehicle control device 60 does not permit the start of the power train. The start permission signal S2 is transmitted to the vehicle control device 60 as an electric signal.

[0062] <The first pattern of the start sequence> Next, the first pattern of the start sequence will be described. As shown in the time chart of FIG. 5, when the vehicle power supply is turned on (time T1), the reaction force control device 40 starts and sequentially executes an initial check, a midpoint learning process, and a rudder angle synchronization process. When the preparation process including the initial check, the midpoint learning process, and the rudder angle synchronization process is completed, the reaction force control device 40 transitions to an assist start waiting state and turns on the start permission signal S2. The assist start waiting state is a state in which the preparation for the reaction force control is complete and it is possible to transition to the normal control state.

[0063] When the vehicle power supply is turned on (time T1), the vehicle control device 60 starts executing predetermined start preparations. After the start preparations are completed, the vehicle control device 60 transitions to a start permission waiting state (time T4). The start permission waiting state is a state waiting for the start of the power train to be permitted by the reaction force control device 40, that is, for the start permission signal S2 to be turned on.

[0064] When the vehicle control device 60 recognizes that the start permission signal S2 has been turned on in the start permission waiting state (time T5), the vehicle control device 60 starts the power train of the vehicle. When the execution of the start process of the power train is completed, the vehicle control device 60 turns on the preparation completion signal S1.

[0065] When the reaction force control device 40 recognizes that the preparation completion signal S1 is on in the assist start waiting state (time T6), it transitions to the normal control state (time 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.

[0066] In this way, when the vehicle control device 60 has completed its own startup preparation, but the preparation process for the reaction force control by the reaction force control device 40 has not been completed, it waits for the completion of the preparation process and then starts the vehicle's power train. For this reason, the vehicle can only run after it has transitioned to the assist start waiting state where the reaction force control device 40 is capable of executing reaction force control. Therefore, it is avoided that the vehicle becomes drivable even though the reaction force control device 40 is in the middle of executing the preparation process. Also, it is possible to start the vehicle in a safer state for the driver, that is, a state where the vehicle can be steered in the direction intended by the driver.

[0067] <Anti - spoofing countermeasure> In the first pattern of the startup sequence, the following is a concern. That is, there is a concern that a third party who has spoofed the reaction force control device 40 or the vehicle control device 60 may fake the turning on of the start permission signal S2 by the reaction force control device 40 or the turning on of the preparation completion signal S1 by the vehicle control device 60. In this case, there is a possibility that the vehicle may transition to a drivable state before the reaction force control device 40 transitions to the assist start waiting state where it is capable of executing reaction force control. Therefore, the reaction force control device 40 is configured to execute the following process.

[0068] <Stop request determination process for the vehicle> When the vehicle power supply is turned on, the reaction force control device 40 executes a stop request determination process for the vehicle. The stop request determination process is a process for determining whether it is necessary to request the vehicle control device 60 to stop the start of the vehicle's power train. The stop request determination process is executed at a predetermined control cycle according to the program stored in the reaction force control device 40.

[0069] As shown in the flowchart of FIG. 6, the reaction force control device 40 determines whether it is necessary to request the vehicle control device 60 to stop the start of the vehicle's power train (step S201).

[0070] The reaction force control device 40 determines whether it is necessary to request the vehicle control device 60 to stop the start of the vehicle's power train based on whether the defined determination conditions are satisfied. The determination conditions are conditions for determining whether the turning on of the start permission signal S2 by the reaction force control device 40 or the turning on of the preparation completion signal S1 by the vehicle control device 60 is disguised.

[0071] The determination conditions include, for example, the following two conditions A1 and A2. When both of the two conditions A1 and A2 are satisfied, the reaction force control device 40 determines that it is necessary to request the vehicle control device 60 to stop the start of the vehicle's power train. Also, when either one of the two conditions A1 and A2 is not satisfied, the reaction force control device 40 determines that it is not necessary to request the vehicle control device 60 to stop the start of the vehicle's power train.

[0072] A1. The start permission signal S2 is off. A2. The preparation completion signal S1 is on. The determination conditions are set based on the following viewpoints. That is, for example, when the preparation completion signal S1 is turned on by the vehicle control device 60 even though the start permission signal S2 is not turned on by the reaction force control device 40, there is a possibility that the turning on of the start permission signal S2 is disguised by a third party pretending to be the reaction force control device 40.

[0073] When it is determined that it is necessary to request the vehicle control device 60 to stop the start of the vehicle's power train (YES in step S201), the reaction force control device 40 turns on the vehicle stop request signal S3 (step S202) and ends the process.

[0074] When it is determined that there is no need to request the vehicle control device 60 to stop the start of the vehicle's power train (NO in step S201), the reaction force control device 40 turns off the vehicle stop request signal S3 (step S203) and ends the process.

[0075] Note that the vehicle stop request signal S3 is information indicating whether to request the vehicle control device 60 to stop the operation of the power train. When the vehicle stop request signal S3 is on, it indicates that the vehicle control device 60 is requested to stop the operation of the power train. When the vehicle stop request signal S3 is off, it indicates that the vehicle control device 60 is not requested to stop the operation of the power train. The vehicle stop request signal S3 is transmitted to the vehicle control device 60 as an electrical signal.

[0076] <Second pattern of the start-up sequence> Next, the second pattern of the start-up sequence will be described. Here, as an example, a case where the turning on of the start permission signal S2 is disguised during the execution of the midpoint learning process, which is one of the preparation processes by the reaction force control device 40, is considered. Also, the start-up preparation of the vehicle control device 60 is completed before the midpoint learning process by the reaction force control device 40 is completed.

[0077] As shown in the time chart of FIG. 7, when the vehicle power supply is turned on (time T1), the reaction force control device 40 starts up and starts executing the initial check. After the initial check by the reaction force control device 40 is normally completed, the midpoint learning process is started. For example, when the turning on of the start permission signal S2 is disguised during the execution of this midpoint learning process (time T7), the vehicle control device 60 recognizes that the start permission signal S2 is already on, for example, at the timing when the start-up preparation is completed. Therefore, after the start-up preparation of the vehicle control device 60 is completed, it immediately starts the vehicle's power train without transitioning to the start permission waiting state. When the execution of the start process of the power train by the vehicle control device 60 is completed, the preparation completion signal S1 is turned on (time T8).

[0078] When the reaction force control device 40 recognizes that the preparation completion signal S1 is on even though the midpoint learning process is in progress, it turns on the vehicle stop request signal S3 (time T9). This is because there is a possibility that the on state of the start permission signal S2 is being forged by a third party posing as the reaction force control device 40.

[0079] After starting the power train of the vehicle, when the vehicle control device 60 recognizes that the vehicle stop request signal S3 is on, it executes a predetermined process. The predetermined process is, for example, a process for stopping the operation of the power train. As a result, the vehicle becomes unable to run. Also, even though the reaction force control device 40 is in the middle of the preparation process, it is suppressed that the vehicle is maintained in a state where it can run due to fraud such as impersonation.

[0080] <Effects of the present embodiment> Therefore, according to the present embodiment, the following effects can be obtained. (1) When the vehicle power is turned on, if information exchange between the reaction force control device 40 and the vehicle control device 60 does not follow a predetermined pattern, the reaction force control device 40 requests the vehicle control device 60 to stop the vehicle from running. The information exchange includes, for example, the vehicle control device 60 recognizing the on state of the start permission signal S2, and the reaction force control device 40 recognizing the preparation completion signal S1. The predetermined pattern includes, for example, after the reaction force control device 40 turns on the start permission signal S2, the vehicle control device 60 turns on the preparation completion signal S1 in response to the on state of this start permission signal S2. When adopting this configuration, there is a concern that the information exchanged between the reaction force control device 40 and the vehicle control device 60 may be forged due to some improper act. In this regard, according to the present embodiment, when information exchange that does not follow the predetermined pattern between the reaction force control device 40 and the vehicle control device 60 occurs, it is possible to suppress the vehicle from running. Therefore, the security is further enhanced.

[0081] (2) When the preparatory process for reaction force control is completed, the reaction force control device 40 permits the vehicle control device 60 to transition the vehicle to a drivable state. Transitioning the vehicle to a drivable state is, for example, starting the vehicle's power train. Also, the permission for the vehicle control device 60 is given, for example, by the reaction force control device 40 turning on the start permission signal S2. The vehicle control device 60 waits for permission from the reaction force control device 40 to transition the vehicle to a drivable state and then transitions the vehicle to a drivable state. For this reason, the vehicle can only travel after the preparatory process of the reaction force control device 40 is completed. Therefore, the vehicle can start to travel in a safer state for the driver.

[0082] (3) When it is recognized that the vehicle is in a drivable state even though the reaction force control device 40 has not permitted the vehicle control device 60 to transition the vehicle to a drivable state, there is a possibility that the permission for the vehicle control device 60 has been forged by an improper act such as impersonation. The forgery of the permission for the vehicle control device 60 is, for example, the forgery of the turning on of the start permission signal S2. That the vehicle is in a drivable state can be recognized, for example, by the preparation completion signal S1 being turned on. According to the present embodiment, when there is a possibility that the permission for the vehicle control device 60 has been forged, the vehicle control device 60 is requested to stop the vehicle. The request to prohibit the vehicle from traveling is made, for example, by the reaction force control device 40 turning on the vehicle stop request signal S3. By the vehicle control device 60 stopping the vehicle in response to the request from the reaction force control device 40, the security is enhanced.

[0083] (4) The preparation process of the reaction force control device 40 includes a midpoint learning process and a steering angle synchronization process. For example, if the vehicle starts running while the steering control device is in the middle of executing the midpoint learning process or the steering angle synchronization process, the driver may have difficulty steering the steering wheel 11 in the intended steering direction. This is because the steering wheel 11 rotates automatically during the execution of the midpoint learning process or the steering angle synchronization process. In this regard, according to the present embodiment, when the preparation process of the reaction force control is completed, the reaction force control device 40 permits the vehicle control device 60 to transition the vehicle to a state where it can run. Therefore, the vehicle can only run after the preparation process of the reaction force control device 40 is completed. Accordingly, the driver can start the vehicle in a safer state without giving the driver a sense of discomfort.

[0084] (5) The vehicle control device 60 controls the start of the power train including the driving source for the vehicle to run. Therefore, by controlling the start of the vehicle's power train through the vehicle control device 60, the vehicle can be transitioned to a state where it can run.

[0085] <Other embodiments> Note that the present embodiment may be implemented with the following modifications. · The preparation completion signal S1, the start permission signal S2, and the vehicle stop request signal S3 may be flags.

[0086] · In the present embodiment, the reaction force motor 21 and the steering motor 31 have two sets of winding groups, but they may have one set of winding groups. In this case, the reaction force control device 40 may have only one of the first system circuit 41 and the second system circuit 42. Also, in this case, the steering control device 50 may have only one of the first system circuit 51 and the second system circuit 52. Note that 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.

Explanation of reference numerals

[0087] 11…Steering wheel 15…Steering wheel 21…Reaction motor 40...Reaction force control device (steering control device) 60...Vehicle control device

Claims

1. It has a control circuit for controlling the drive of a reaction force motor that generates a steering reaction force applied to a steering wheel with the power transmission to the steered wheels of the vehicle separated, when the vehicle power supply is turned on, when information exchange not following a defined pattern occurs between the control circuit and a vehicle control device that controls the running of the vehicle, the steering control device that requests the vehicle control device to stop the running of the vehicle.

2. When the execution of the preparation process executed upon the vehicle power supply being turned on is completed, the control circuit permits the vehicle control device to transition the vehicle to a state where it can run, and when it is recognized through the vehicle control device that the vehicle is in a state where it can run, it transitions to a normal control state where it executes reaction force control to generate a steering reaction force in the reaction force motor, according to Claim 1. The steering control device described.

3. When it is recognized through the vehicle control device that the vehicle is in a state where it can run, even though the control circuit has not permitted the vehicle control device to transition the vehicle to a state where it can run, the steering control device according to Claim 2 that requests the vehicle control device to stop the running of the vehicle.

4. Assuming that the steering range of the steering wheel is restricted to less than 360°, the preparation process includes a midpoint learning process of learning the steering neutral position of the steering wheel by operating the steering wheel to a first operating end and then reversely operating it to a second operating end, and a rudder angle synchronization process of correcting the rotational position of the steering wheel so that the rotational position of the steering wheel becomes the rotational position corresponding to the steering position of the steered wheels. The steering control device according to Claim 2 or Claim 3.

5. The vehicle control device controls the start of a power train including a drive source for running the vehicle. The steering control device according to any one of Claims 1 to 4.

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