Steering control device and steering control method

Abstract

The invention relates to a steering control device and a steering control method. A steering control device (1) is applied to a vehicle steering system (2) for steering the travel of a vehicle. A steering control device (1) includes a rudder angle control unit (50, 60) that performs control with reference to a rudder angle variable obtained with respect to steering. A rudder angle control unit (50, 60) executes a control information setting process that sets control information that is a value indicating linear movement of a vehicle and that is a reference for a rudder angle variable. In the control information setting process, the rudder angle control units (50, 60) enable steering control for the travel of the vehicle by completing the setting of the control information after the power source of the vehicle steering system (2) is turned on.

Description

Technical Field

[0001] The present disclosure relates to a steering control device and a steering control method. Background Art

[0002] For example, Japanese Unexamined Patent Application Publication No. 2021-195084 describes a steer-by-wire type steering device equipped in a vehicle. The steer-by-wire type steering device includes a dynamic power transmission path cut off between a steering wheel of the vehicle and a steering wheel of the vehicle. The vehicle includes a reaction force control unit and a steering control unit for controlling the steer-by-wire type steering device. The reaction force control unit is configured to perform a steering angle midpoint setting process for obtaining a neutral position of the steering wheel.

[0003] The above-mentioned steering angle midpoint setting process is a process for enabling control of the steering control device, etc. while the vehicle is running. For example, in the case where the reaction force control unit has a condition in which the steering angle midpoint setting process cannot be completed, it is impossible to achieve control of the steering control device, etc. while the vehicle is running. Summary of the invention

[0004] In one aspect of the present disclosure, a steering control device is applied to a vehicle steering system for steering the travel of a vehicle. The steering control device includes a steering angle control unit configured to perform control with reference to a steering angle variable obtained with respect to the steering. The steering angle control unit is configured to perform a control information setting process of setting control information, which is a value indicating the straight-line movement of the vehicle and is a reference of the steering angle variable. In the control information setting process, the steering angle control unit completes the setting of the control information after the power source of the vehicle steering system is turned on, so that the control of steering the travel of the vehicle can be performed. The steering angle control unit includes a control circuit configured to control the steering angle variable in coordination with each other. The control circuit is configured to be able to steer the travel of the vehicle under the condition that the setting of the control information has been completed in all the control circuits in the control circuit in the execution of the control information setting process. The control information setting process includes the following coordination process: in the case where the setting of the control information has been completed in the first control circuit group in the control circuit and the setting of the control information has not been completed in the second control circuit group in the control circuit, coordination is performed so that all the control circuits in the control circuit can complete the setting of the control information.

[0005] In the above configuration, even in the case where there is a control circuit in which the setting of the control information has not been completed, the coordination process is performed so that the setting of the control information can be completed in all the control circuits in the control circuit. Thus, for example, the occurrence of a situation in which the setting of the control information in all the control circuits in the control circuit cannot be completed and the event is endlessly repeated can be suppressed. Therefore, the extension of the period after the power source of the vehicle steering system is turned on and before the control of the steering operation for the travel of the vehicle is enabled can be suppressed.

[0006] In the above-mentioned steering control device, the coordination process may include the following state coordination process: coordinating the state of the first control circuit group so that each control circuit in the first control circuit group is changed to a state capable of executing the control information setting process again. The first control circuit group may be configured so that each control circuit in the first control circuit group executes the control information setting process again after coordination through the state coordination process.

[0007] In the above configuration, in the coordination process, the state coordination process makes it possible to make the control circuit for which the setting of the control information has been completed perform the control information setting process again. Thus, all the control circuits in the control circuit can be made to perform the control information setting process again regardless of whether the setting of the control information has been completed. This state coordination process is a technique that is particularly effective in the case where each of the control circuits sets the control information, for example, by rotating the steering wheel of a vehicle.

[0008] The above-mentioned vehicle steering system may include a dynamic power transmission path cut off between a steering control unit and a steering unit, the steering control unit being steered by a steering wheel of the vehicle, and the steering unit being operated to steer the steering wheel of the vehicle. The steering angle control unit may include a reaction force control unit, which includes a first control circuit. The reaction force control unit may be configured to control the operation of the steering control unit by referring to a steering control variable obtained from the steering control unit regarding the steering control, so that a steering control reaction force is given to the steering wheel. Each of the first control circuits of the reaction force control unit may be configured to perform a control information setting process based on a corresponding value obtained when the steering wheel is rotated to an extreme position in a first direction and a second direction. Each of the first control circuits of the reaction force control unit may be configured to perform a state coordination process in the control information setting process.

[0009] In the above configuration, by the state coordination processing, the setting of the control information can be completed in all the control circuits in the control circuit of the reaction force control unit. Thus, even in the case where each of the control circuits of the reaction force control unit sets the control information by, for example, rotating the steering wheel of the vehicle, all the control circuits in the control circuit can perform the control information setting processing again. That is, the occurrence of an event in which the steering wheel of the vehicle cannot be rotated due to, for example, the difference in the internal state between the control circuits of the reaction control unit can be suppressed.

[0010] In the above-mentioned steering control device, the coordination process may include the following control information coordination process: coordinating the second control circuit group so that the setting of the control information is completed by setting the control information using the control information after the setting in the first control circuit group is completed. The control circuit may be configured so that the setting of the control information is completed in all control circuits in the control circuit after coordination by the control information coordination process.

[0011] In the above configuration, in the coordination process, the control information coordination process makes it possible to use the control information after the setting is completed in the control circuit in which the setting of the control information has been completed, so that the setting of the control information is also completed in the control circuit in which the setting of the control information has not been completed. Thus, when there is a control circuit in which the setting of the control information has been completed, the setting of the control information can be completed in all the control circuits in the control circuit. This control information coordination process is a particularly effective technique in the case where each of the control circuits sets the control information by correcting the rudder angle variable, for example.

[0012] The above-mentioned vehicle steering control system may include a dynamic power transmission path cut off between a steering control unit and a steering unit, the steering control unit is steered by the steering wheel of the vehicle, and the steering unit is operated to steer the steering wheel of the vehicle. The steering angle control unit may include a steering control unit, which includes a second control circuit. The steering control unit may be configured to control the operation of the steering unit by referring to a steering variable obtained from the steering unit regarding the steering control, so that a steering force is given to the steering wheel. Each of the second control circuits of the steering control unit may be configured to perform a control information setting process by correcting the steering variable using a correction variable obtained from the steering unit in addition to the steering variable. Each of the second control circuits of the steering control unit may be configured to perform a control information coordination process in the control information setting process.

[0013] In the above configuration, the control information coordination process makes it possible to complete the setting of the control information in all the control circuits in the control circuit of the steering control unit. Thus, even in the case where each of the control circuits of the steering control unit sets the control information by correcting the steering variable using the correction information obtained in addition to the steering variable, all the control circuits in the control circuit can complete the setting of the control information. That is, even when the control circuit of the steering control unit includes a control circuit that fails to obtain the steering variable or the correction variable, it is possible to quickly cope with it.

[0014] The above-mentioned vehicle steering system may include a dynamic power transmission path cut off between a steering unit and a steering unit, the steering unit is steered by the steering wheel of the vehicle, and the steering unit is operated to steer the steering wheel of the vehicle. The steering angle control unit may include: a reaction force control unit, the reaction force control unit includes a first control circuit; and a steering control unit, the steering control unit includes a second control circuit. The reaction force control unit may be configured to control the operation of the steering unit by referring to a steering variable obtained from the steering unit regarding the steering operation, so that a steering reaction force is given to the steering wheel. The steering control unit may be configured to control the operation of the steering unit by referring to a steering variable obtained from the steering unit regarding the steering operation, so that a steering force is given to the steering wheel. The coordination process may include: a state coordination process-coordinating the state of the first control circuit group so that each control circuit in the first control circuit group is transformed to a state in which the control information setting process can be performed again; and a control information coordination process-coordinating the second control circuit group so that the setting of the control information is completed by setting the control information using the control information after the setting in the first control circuit group is completed. Each of the first control circuits of the reaction force control unit may be configured to perform the state coordination process in the control information setting process. Each of the first control circuits may be configured to, in the case of executing the state coordination process, execute the control information setting process again after coordination by the state coordination process. Each of the second control circuits of the steering control unit may be configured to execute the control information coordination process in the control information setting process. The second control circuit may be configured so that, in the case of executing the control information coordination process, after coordination by the control information coordination process, the setting of the control information is completed in all the control circuits in the control circuit.

[0015] Another aspect of the present disclosure is a steering control method of a vehicle steering system for steering the travel of a vehicle. The steering control method includes a rudder angle control process - performing control with reference to a rudder angle variable obtained with respect to the steering. The rudder angle control process includes setting control information, which is a value indicating the linear movement of the vehicle and is a reference for the rudder angle variable. Setting the control information enables control of steering the travel of the vehicle by completing the setting of the control information after the power source of the vehicle steering system is turned on. The rudder angle control process includes processing performed by a control circuit, which is configured to control the rudder angle variable in coordination with each other. The processing performed by the control circuit enables control of steering the travel of the vehicle under the condition that the setting of the control information has been completed in all control circuits in the control circuit in the setting of the control information in the control circuit. Setting the control information includes performing coordination so that all control circuits in the control circuit can complete the setting of the control information when the setting of the control information has been completed in the first control circuit group in the control circuit and the setting of the control information has not been completed in the second control circuit group in the control circuit.

[0016] According to the present disclosure, it is possible to suppress extension of a period after the electric power source of the vehicle steering system is turned on and before control for steering the travel of the vehicle is enabled. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals denote like elements, and in which:

[0018] Figure 1 is a diagram showing the configuration of a steer-by-wire type steering device according to an embodiment;

[0019] Figure 2 It is shown Figure 1 A block diagram of the electrical configuration of the steering control device;

[0020] Figure 3 It is shown by Figure 1 A flowchart of the process of the steering control CPU executed in the startup state;

[0021] Figure 4 It is shown Figure 3 A flowchart of the processing procedure on the reaction force side in the rudder angle correction process;

[0022] Figure 5 It is shown Figure 3 A flowchart of the processing procedure of the steering side in the rudder angle correction process;

[0023] Figure 6 is a diagram showing the manner in which state coordination processing is performed in the reaction force CPU; and

[0024] Figure 7 It is a diagram showing the manner in which control information coordination processing is performed in the steering CPU. DETAILED DESCRIPTION

[0025] A steering control device according to an embodiment will be described. Figure 1 As shown, the vehicle steering system 2 includes a steering control device 1. The vehicle steering system 2 includes a steering unit 4 and a steering unit 6. The steering unit 4 is steered by the driver through a steering wheel 3 of the vehicle as a steering member. The steering unit 6 steers the right steering wheel 5 and the left steering wheel 5 of the vehicle in response to the steering operation input by the driver to the steering unit 4. For example, the vehicle steering system 2 in the embodiment has a structure in which the dynamic power transmission path between the steering unit 4 and the steering unit 6 is always mechanically cut off. The dynamic power transmission path between the steering actuator 12 described later and the steering actuator 31 described later is always mechanically cut off. That is, the vehicle steering system 2 includes a steer-by-wire type steering device.

[0026] The steering unit 4 includes a steering shaft 11 and a steering actuator 12. The steering shaft 11 is coupled to the steering wheel 3. At an end portion 11a of the steering shaft 11 on the opposite side of the side where the steering shaft 11 is coupled to the steering wheel 3, a stopper mechanism 11b is provided. The stopper mechanism 11b specifies the rotation range of the steering shaft 11. Thus, the rotation range of the steering wheel 3 that rotates integrally with the steering shaft 11 is specified by the stopper mechanism 11b. For example, the steering wheel 3 can be rotated so that the rotation range is a range between a right limit position 3a and a left limit position 3b.

[0027] The steering actuator 12 includes a reaction force motor 13 and a steering side speed reduction mechanism 14. The reaction force motor 13 is a steering side motor that gives a steering reaction force as a force resisting the steering of the steering wheel 3 to the steering wheel 3 through the steering shaft 11. For example, the reaction force motor 13 is connected to the steering shaft 11 through the steering side speed reduction mechanism 14 composed of a worm and a worm wheel. For example, a three-phase brushless motor is used as the reaction force motor 13 in the embodiment.

[0028] The steering unit 6 includes a pinion shaft 21, a rack shaft 22 as a steering shaft, and a rack housing 23. The pinion shaft 21 and the rack shaft 22 are coupled to each other at a predetermined crossing angle. Pinion teeth 21a formed on the pinion shaft 21 mesh with rack teeth 22a formed on the rack shaft 22, and thus constitute a rack-and-pinion mechanism 24. The pinion shaft 21 corresponds to a rotation shaft that allows conversion into a steering angle θi as a steering position of the steering wheel 5. The rack housing 23 accommodates the rack-and-pinion mechanism 24.

[0029] One end of the pinion shaft 21 on the opposite side to the side where the pinion shaft 21 is coupled to the rack shaft 22 protrudes from the rack housing 23. Both ends of the rack shaft 22 protrude from both ends of the rack housing 23 in the axial direction of the rack housing 23. The tie rod 26 is coupled to both ends of the rack shaft 22 through the rack ends 25, each of which is a ball joint. The distal end of the tie rod 26 is coupled to a steering knuckle not shown to which the right and left steering wheels 5, 5 are attached, respectively.

[0030] The steering unit 6 includes a steering actuator 31. The steering actuator 31 includes a steering motor 32, a transmission mechanism 33, and a conversion mechanism 34. The steering motor 32 is a steering-side motor that applies a steering force for steering the steering wheel 5 to the rack shaft 22 through the transmission mechanism 33 and the conversion mechanism 34. For example, the steering motor 32 transmits the rotation to the conversion mechanism 34 through the transmission mechanism 33 as a belt transmission mechanism. For example, the transmission mechanism 33 converts the rotation of the steering motor 32 into the reciprocating motion of the rack shaft 22 through the conversion mechanism 34 as a ball screw mechanism. For example, a three-phase brushless motor is used as the steering motor 32 in the embodiment.

[0031] In the vehicle steering system 2, in response to the steering manipulation of the steering wheel 3 by the driver, the motor torque is given as a steering force from the steering actuator 31 to the rack shaft 22, and thus the steering angle θi of the steering wheel 5 is changed. At this time, a steering reaction force resisting the steering manipulation by the driver is given to the steering wheel 3 from the steering actuator 12. Thus, in the vehicle steering system 2, the steering torque Th required for the steering manipulation of the steering wheel 3 is changed by the steering reaction force as the motor torque given from the steering actuator 12.

[0032] The reason why the pinion shaft 21 is provided is because the rack shaft 22 is supported inside the rack housing 23 together with the pinion shaft 21. The rack shaft 22 is supported to be movable in the axial direction of the rack shaft 22 and is pressed to the pinion shaft 21 by a support mechanism not shown provided in the vehicle steering system 2. Thus, the rack shaft 22 is supported inside the rack housing 23. Instead of using the pinion shaft 21, another support mechanism for supporting the rack shaft 22 in the rack housing 23 may be provided.

[0033] Electrical configuration of steering control device

[0034] like Figure 1 As shown, the reaction force motor 13 and the steering motor 32 are connected to the steering control device 1. The steering control device 1 controls the actuation of the respective motors 13,32.

[0035] Detection results of the various sensors are input to the steering control device 1 . Examples of the various sensors include a torque sensor 41 , a steering-side rotation angle sensor 42 , a steering-side rotation angle sensor 43 , a vehicle speed sensor 44 , and a pinion absolute angle sensor 45 .

[0036] The torque sensor 41 is provided at a portion of the steering shaft 11 between the steering wheel 3 and the steering-side speed reduction mechanism 14. The torque sensor 41 detects a steering torque Th which is a value indicating a torque given to the steering shaft 11 by the steering of the steering wheel 3 by the driver. The steering torque Th is detected based on the twisting of a torsion bar 41a in the steering shaft 11 which is located in the middle of the steering shaft 11 and provided between the steering wheel 3 and the steering-side speed reduction mechanism 14. The steering-side rotation angle sensor 42 is provided at the reaction motor 13. The steering-side rotation angle sensor 42 detects a rotation angle θa which is a rotation angle of a rotation shaft of the reaction motor 13 and is an angle within a range of 360 degrees. The steering-side rotation angle sensor 43 is provided at the steering motor 32. The steering-side rotation angle sensor 43 detects a rotation angle θb which is a rotation angle of a rotation shaft of the steering motor 32 and is an angle within a range of 360 degrees. The vehicle speed sensor 44 detects a vehicle speed V which is a traveling speed of the vehicle. The pinion absolute angle sensor 45 is provided at the pinion shaft 21. The pinion absolute angle sensor 45 detects the pinion absolute rotation angle θabp, which is an actual measured value of the angle of the rotation axis of the pinion shaft 21 within a range exceeding 360°. In the embodiment, the rotation angle θa and the rotation angle θb are examples of steering angle variables. In addition, the rotation angle θa is an example of a steering manipulation variable. In addition, the rotation angle θb is an example of a steering variable. In addition, the pinion absolute rotation angle θabp is an example of a correction variable.

[0037] The power source system 46 is connected to the steering control device 1. The power source system 46 includes a battery 47. The battery 47 is a secondary battery equipped in the vehicle, and is a power source to which power is supplied for operating the reaction force motor 13 and the steering motor 32. In addition, the battery 47 is a power source to which power is supplied for operating the steering control device 1.

[0038] A start switch 48 ( Figure 1 4) such as an ignition switch. The start switch 48 is provided in the middle of the power supply line L2 which is separated from the power supply line L1 and which is one of the two power supply lines L1 and L2 connecting the steering control device 1 and the battery 47. The start switch 48 is manipulated when various functions are activated so that a driving source for the vehicle such as an engine is activated and the vehicle can run. The electrical continuity of the power supply line L2 is turned on or off by manipulating the start switch 48. In the embodiment, the operating state of the vehicle steering system 2 is associated with the operating state of the vehicle. The power supply line L1 is basically always electrically continuous, but as a function of the vehicle steering system 2, the electrical continuity of the power supply line L1 is indirectly turned on or off according to the operating state of the vehicle steering system 2. The operating state of the vehicle steering system 2 is associated with the on-off state of the electrical continuity of the power supply lines L1 and L2, which is the state of the power supply of the battery 47. In the operating state of the vehicle steering system 2, when the electrical continuity of the power supply lines L1 and L2 is turned on based on the manipulation of the start switch 48, the power source is turned on. In the operating state of the vehicle steering system 2 , when the electrical continuity of the power supply lines L1 , L2 is disconnected based on the manipulation of the start switch 48 , the power source is disconnected.

[0039] Function of the steering control

[0040] like Figure 2 As shown, the steering control device 1 includes a reaction force control unit 50 and a steering control unit 60. The reaction force control unit 50 controls the steering wheel 3 as a control object. In order to control the steering reaction force as a controlled variable of the control object, the reaction force control unit 50 controls the driving of the steering actuator 12, more specifically, controls the driving of the reaction force motor 13. The steering control unit 60 controls the rack shaft 22 as a control object. In order to control the steering force as a controlled variable of the control object, the steering control unit 60 controls the driving of the steering actuator 31, more specifically, controls the driving of the steering motor 32. For example, the reaction force control unit 50 and the steering control unit 60 perform transmission and reception of information with each other through a local network 49 for serial communication or the like. The reaction force control unit 50 constitutes a reaction force system RS by combining with the steering unit 4. The steering control unit 60 constitutes a steering system TS by combining with the steering unit 6. The process of controlling the driving of the reaction force motor 13 by the reaction force control unit 50 is a reaction force control process. The process of controlling the driving of the steering motor 32 by the steering control unit 60 is a steering control process. In the embodiment, the reaction force control unit 50 and the steering control unit 60 are examples of a steering angle control unit. Furthermore, the reaction force control process and the steering control process are examples of a steering angle control process.

[0041] The reaction force control unit 50 includes a central processing unit (hereinafter, referred to as "CPU") 51 and a memory 52. ​​The CPU 51 executes a program stored in the memory 52 at a predetermined calculation cycle, and thus the reaction force control unit 50 performs various processes. The steering control unit 60 includes a central processing unit (hereinafter, referred to as "CPU") 61 and a memory 62. The CPU 61 executes a program stored in the memory 62 at a predetermined calculation cycle, and thus the steering control unit 60 performs various processes. The CPUs 51, 61 and the memories 52, 62 constitute a microcomputer as a processing circuit. The memories 52, 62 include computer-readable media such as random access memories (RAM) and read-only memories (ROM). The implementation of various processes by software is an example. The processing circuits included in the reaction force control unit 50 and the steering control unit 60 may be configured so that at least some of the processes are implemented by hardware circuits such as logic circuits.

[0042] The reaction force control unit 50 includes a plurality of control systems in which a CPU 51 and a memory 52 are combined so as to perform various processes. For example, the plurality of control systems are composed of two systems, and the two systems include a reaction force main system RSa having a main CPU 51a and a main memory 52a and a reaction force subsystem RSb having a sub-CPU 51b and a sub-memory 52b. The same is true for the steering control unit 60. That is, the steering control unit 60 includes a plurality of control systems in which a CPU 61 and a memory 62 are combined so as to perform various processes. For example, the plurality of control systems are composed of two systems, and the two systems include a steering main system TSa having a main CPU 61a and a main memory 62a and a steering subsystem TSb having a sub-CPU 61b and a sub-memory 62b. In an embodiment, CPUs 51a, 51b and CPUs 61a, 61b are examples of control circuits. The processes performed by CPUs 51a, 51b and CPUs 61a, 61b are examples of control circuit processes.

[0043] The CPUs 51a, 51b of the reaction force control unit 50 receive the steering torque Th, the vehicle speed V, and the rotation angle θa. In the embodiment, the steering side rotation angle sensor 42 includes a sensor 42a for the reaction force main system RSa and a sensor 42b for the reaction force subsystem RSb. The main CPU 51a receives the rotation angle θa as the rotation angle θaa detected by the sensor 42a. The sub-CPU 51b receives the rotation angle θa as the rotation angle θab detected by the sensor 42b. In addition, the CPUs 51a, 51b receive steering information obtained from the steering control unit 60 through the local network 49. The CPUs 51a, 51b calculate the control signal MSs for controlling the steering reaction force based on various information including the steering torque Th, the vehicle speed V, and the rotation angle θa, which is a signal to be output to the reaction force inverter 53. The reaction force inverter 53 is a drive circuit that converts the DC voltage of the battery 47 into an AC voltage and applies the AC voltage to the reaction force motor 13. In this case, the CPU 51a, 51b refers to the current iu1, iv1, iw1 flowing through the reaction force motor 13. The current iu1, iv1, iw1 is quantified as the voltage drop amount at the shunt resistor provided at each branch of the reaction force inverter 53.

[0044] In an embodiment, the reaction force inverter 53 includes an inverter 53a for the reaction force main system RSa and an inverter 53b for the reaction force subsystem RSb. The inverter 53a applies a voltage to the main winding group 13a included in the reaction force motor 13. The inverter 53b applies a voltage to the sub-winding group 13b included in the reaction force motor 13. The main CPU 51a calculates the control signal MSsa output to the inverter 53a, and refers to the currents iu1a, iv1a, iw1a in the inverter 53a. The sub-CPU 51b calculates the control signal MSsb output to the inverter 53b, and refers to the currents iu1b, iv1b, iw1b in the inverter 53b. Thus, the CPUs 51a and 51b control the drive of the reaction force motor 13 so as to generate a motor torque that causes the steering manipulation reaction force.

[0045] The CPUs 51a and 51b convert the rotation angle θa into an integral rotation angle as an integral value starting from the reaction force reference value θns stored in the memories 52a and 52b, that is, into an absolute rotation angle. The absolute rotation angle is a value converted within a range exceeding 360° by counting the number of rotations of the reaction force motor 13 starting from the reaction force reference value θns. For example, the reaction force reference value θns is a value indicating a straight-line moving state as a steering state of the steering wheel 3 when the vehicle moves straight. In the embodiment, the reaction force reference value θns is a value indicating a steering neutral position as a rotation position of the steering wheel 3 in the straight-line moving state, and is an example of control information. Each of the CPUs 51a and 51b calculates the steering angle θs by multiplying the absolute rotation angle obtained by the conversion by a conversion factor based on the rotation speed ratio of the steering side speed reduction mechanism 14. Each of the CPUs 51a and 51b calculates the steering angle θs as an absolute angle relative to the steering neutral position, that is, the reaction force reference value θns. The steering angle θs obtained in this manner is used to calculate the control signal MSs. The steering information used by the CPUs 51 a , 51 b , such as the steering angle θs, is output to the steering control unit 60 via the local network 49 .

[0046] The CPUs 61a, 61b of the steering control unit 60 receive the vehicle speed V, the rotation angle θb, and the pinion absolute rotation angle θabp. In the embodiment, the steering side rotation angle sensor 43 includes a sensor 43a for the steering main system TSa and a sensor 43b for the steering subsystem TSb. The main CPU 61a receives the rotation angle θb as the rotation angle θba detected by the sensor 43a. The sub-CPU 61b receives the rotation angle θb as the rotation angle θbb detected by the sensor 43b. In addition, the CPUs 61a, 61b receive the steering manipulation information obtained from the reaction force control unit 50 through the local network 49. The CPUs 61a, 61b calculate the control signal MSt for controlling the steering force based on various information including the vehicle speed V, the rotation angle θb, and the pinion absolute rotation angle θabp, which is a signal output to the steering inverter 63. The steering inverter 63 is a drive circuit that converts the DC voltage of the battery 47 into an AC voltage and applies the AC voltage to the steering motor 32. In this case, the CPU 61a, 61b refers to the currents iu2, iv2, iw2 flowing through the steering motor 32. The currents iu2, iv2, iw2 are quantified as voltage drop amounts at shunt resistors provided at respective branches of the steering inverter 63.

[0047] In an embodiment, the steering inverter 63 includes an inverter 63a for the steering main system TSa and an inverter 63b for the steering subsystem TSb. The inverter 63a applies a voltage to the main winding group 32a included in the steering motor 32. The inverter 63b applies a voltage to the sub-winding group 32b included in the steering motor 32. The main CPU 61a calculates the control signal MSta output to the inverter 63a, and refers to the currents iu2a, iv2a, iw2a in the inverter 63a. The sub-CPU 61b calculates the control signal MStb output to the inverter 63b, and refers to the currents iu2b, iv2b, iw2b in the inverter 63b. Thus, the CPUs 61a and 61b control the drive of the steering motor 32 so that a motor torque that causes a steering force is generated.

[0048] The CPU 61a, 61b converts the rotation angle θb into an integral rotation angle as an integral value starting from the steering reference value θnt stored in the memory 62a, 62b, that is, into an absolute rotation angle. The absolute rotation angle is a value converted within a range exceeding 360° by counting the number of rotations of the steering motor 32 starting from the rotation reference value θnt. For example, the steering reference value θnt is a value indicating a linear movement state as a steering state of the rack shaft 22 when the vehicle moves linearly. In the embodiment, the steering reference value θnt is a value indicating a rack neutral position as a position of the rack shaft 22 in the linear movement state, and is an example of control information. Each of the CPUs 61a, 61b calculates the pinion angle θp by multiplying the absolute rotation angle obtained by the conversion by a conversion factor based on the rotation speed ratio of the transmission mechanism 33, the lead of the conversion mechanism 34, and the rotation speed ratio of the rack and pinion mechanism 24. Each of the CPUs 61a, 61b calculates the pinion angle θp, which is the actual rotation angle of the pinion shaft 21, as an absolute angle relative to the rack neutral position, that is, the steering reference value θnt. The pinion angle θp obtained in this way is used to calculate the control signal MSt. The steering information such as the pinion angle θp used by the CPUs 61a, 61b is output to the reaction force control unit 50 via the local network 49.

[0049] Processing to be performed in the startup state

[0050] After the start switch 48 is turned on in the off state of the power source and the power source is turned on, the steering control device 1 is changed to the start state before changing to the normal control state. In this case, depending on whether the IG signal sg output by the start switch 48 has been input, each of the CPUs 51a, 51b of the reaction force control unit 50 determines whether the power source is in the on state or in the off state, and performs processing such as initial inspection processing. Similarly, each of the CPUs 61a, 61b of the steering control unit 60 determines whether the power source is in the on state or in the off state, and performs processing such as initial inspection processing. In the following, the CPUs 51a, 51b of the reaction force control unit 50 are sometimes collectively referred to as "reaction force CPUs". In addition, the CPUs 61a, 61b of the steering control unit 60 are sometimes collectively referred to as "steering CPUs". In addition, the "reaction force CPU" and the "steering CPU" are sometimes collectively referred to as "steering CPUs".

[0051] like Figure 3 As shown, in the startup state, the steering CPU performs an initial check process (step 100). The initial check process includes a check process regarding the operation of the reaction force system RS and the steering system TS, such as a check process regarding whether each CPU and each memory of the steering CPU are operating normally. The initial check process includes a check process regarding communication through the local network 49. The initial check process includes a check process regarding reading various information from a memory corresponding to each CPU of the steering CPU. In the initial check process, the various information read by the steering CPU from the memory corresponding to each CPU includes a reaction force reference value θns and a steering reference value θnt.

[0052] Subsequently, the steering CPU determines whether the rudder angle correction process has been completed (step 102). In step 102, when the steering CPU can determine that the corresponding processes on the reaction force side and the steering side have been completed, the steering CPU determines that the rudder angle correction process has been completed. In this case, when the reaction force control unit 50 can determine that the corresponding processes in the systems RSa, RSb have been completed, the reaction force control unit 50 determines that the process on the reaction force side has been completed. Similarly, when the steering control unit 60 can determine that the corresponding processes in the systems TSa, TSb have been completed, the steering control unit 60 determines that the process on the steering side has been completed. The rudder angle correction process will be described in detail later.

[0053] Subsequently, in the case where the steering CPU determines that the steering angle correction process has been completed (step 102: Yes), the steering CPU performs a steering angle synchronization process (step 104). The steering angle synchronization process includes a process of synchronizing the positional relationship between the steering wheel 3 and the steering wheel 5 based on at least one of the rotation of the steering wheel 3 and the steering of the steering wheel 5. As a result of the steering angle synchronization process, the steering angle θs as the rotational position of the steering wheel 3 and the steering angle θi as the steering position of the steering wheel 5, that is, the pinion angle θp, have a predetermined corresponding relationship.

[0054] Thereafter, the steering CPU transitions to the normal control state because the processing in the start state has been completed. The normal control state is a state regarding the execution of a normal reaction force process and a normal steering process for steering control for operating the steering unit 4 and the steering unit 6 in response to the steering operation performed by the driver. In this case, the reaction force system RS causes the steering unit 4 to operate in cooperation with the steering unit 6. In addition, the steering system TS causes the steering unit 6 to operate in cooperation with the steering unit 4.

[0055] On the other hand, in the case where the steering angle correction process is being executed in step 102 (step 102: No), the steering CPU determines whether a timeout has occurred (step 106). In step 106, the steering CPU determines whether the elapsed time from the start of the steering angle correction process has exceeded the upper limit time that satisfies the timeout condition. In the embodiment, for example, the upper limit time is a value within the range in which the steering angle correction process on the steering side can be repeated a plurality of times.

[0056] Subsequently, in the case where the timeout condition is not satisfied (step 106: No), the steering CPU continues the processing in step 102, i.e., executes the steering angle correction processing. On the other hand, in the case where the timeout condition is satisfied (step 106: Yes), the steering CPU cannot complete the processing in the start state, and therefore, transitions to the function stop state such as the stop of the function of the steering control device 1.

[0057] Rudder angle correction processing on the reaction force side

[0058] like Figure 4As shown, in the rudder angle correction process on the reaction force side, the reaction force CPU determines whether it is necessary to perform the rudder angle correction process (step 202). In step 202, in the case where the reaction force CPU cannot read the reaction force reference value θns in the initial check process (step 100), the reaction force CPU determines that it is necessary to perform the rudder angle correction process. In the case where the reaction force reference value θns is not internally set, the reaction force CPU cannot read the reaction force reference value θns in the initial check process. For example, in a state after the battery 47 is disassembled and replaced, the reaction force reference value θns has not been internally set. Similarly, in a state after a read abnormality or a write abnormality occurs regarding the reaction force reference value θns, the reaction force reference value θns has not been internally set.

[0059] Subsequently, in the case where the reaction force CPU can read the reaction force reference value θns in the initial check process (step 100) and therefore there is no need to perform the steering angle correction process (step 202: No), the reaction force CPU ends the process and completes the steering angle correction process on the reaction force side. The notification of the completion of the process on the reaction force side is provided to the steering CPU via the local network 49. In the case where both the completion of the process on the reaction force side and the notification of the completion of the steering angle correction process on the steering side are satisfied and received from the steering CPU, the reaction force CPU can make a determination of "Yes" in step 102.

[0060] On the other hand, in the case where the reaction force CPU cannot read the reaction force reference value θns in the initial check process (step 100) and therefore needs to perform the steering angle correction process (step 202: yes), the reaction force CPU performs a control information setting process (step 204). In step 204, the control information setting process performed by the reaction force CPU includes a process of a reference rotation angle θa. The reaction force CPU includes an integral rotation angle acquisition process for calculating a temporary steering angle θsi, which is an integral value obtained using the position of the rotation angle θa when the power source is in the on state as a temporary reference value. The temporary steering angle θsi is an integral rotation angle, i.e., an absolute rotation angle. The control information setting process on the reaction force side includes a learning process in which each CPU of the reaction force CPU acquires a value by rotating the steering wheel 3 to the extreme positions 3a, 3b in the right and left directions.

[0061] For example, Figure 6As shown, the learning process includes a process of rotating the steering wheel 3 in one of the right and left directions (i.e., in the right direction as the first direction). The rotation of the steering wheel 3 is performed by such feedback control that the temporary steering angle θsi follows the target steering angle θs*. The target steering angle θs* is a value that is gradually changed and updated from the value of the temporary steering angle θsi at the start of the learning process to exceed the right limit position 3a.

[0062] In addition, the learning process includes a process of temporarily storing the right limit position θrl in the case where the steering wheel 3 has reached the right limit position 3a. For example, it is determined whether the steering wheel 3 has reached the limit position 3a by monitoring the current iu1, iv1, iw1, the steering torque Th, and the angular velocity ωs as the amount of change of the temporary steering angle θsi. When it is determined that the steering wheel 3 has reached the right limit position 3a, the right limit position θrl is the temporary steering angle θsi.

[0063] In addition, the learning process includes a process of rotating the steering wheel 3 in the other direction of the right direction and the left direction (i.e., the left direction as the second direction). Similar to the process of rotating the steering wheel 3 in the right direction, this process is performed by such feedback control that the temporary steering angle θsi follows the target steering angle θs*. The target steering angle θs* is a value that is gradually changed and updated from the value of the temporary steering angle θsi when the steering wheel 3 has reached the right limit position 3a to exceed the left limit position 3b.

[0064] In addition, the learning process includes a process of temporarily storing the left limit position θll in the case where the steering wheel 3 has reached the left limit position 3b. Similar to the determination as to whether the steering wheel 3 has reached the right limit position 3a, whether the steering wheel 3 has reached the limit position 3b is determined by, for example, monitoring the current iu1, iv1, iw1, the steering torque Th, and the angular velocity ωs as the amount of change of the temporary steering angle θsi. When it is determined that the steering wheel 3 has reached the left limit position 3b, the left limit position θll is the temporary steering angle θsi.

[0065] In addition, the learning process includes a process of calculating a value corresponding to half of the sum of the temporarily stored right limit position θrl and left limit position θll as the reaction force midpoint value θcs. The reaction force midpoint value θcs obtained in this way is written and set as the reaction force reference value θns by the reaction force CPU (i.e., by each of the CPUs 51a, 51b).

[0066] Subsequently, the reaction force CPU determines whether the setting of the reaction force reference value θns has been completed in both systems (step 206). In step 206, the reaction force CPU determines whether the setting of the reaction force reference value θns has been completed by each of the CPUs 51a, 51b. In addition, the reaction force CPU determines whether there is a CPU in a system in which the setting of the reaction force reference value θns has not been completed and there is a CPU in a system in which the setting of the reaction force reference value θns has been completed. During the learning process, as a result of the learning process, the CPUs 51a, 51b provide each other with a notification of the completion of the setting of the reaction force reference value θns through inter-microcomputer communication or the like.

[0067] When none of the CPUs 51a, 51b completes the setting of the reaction force reference value θns, the reaction force CPU does not execute step 206. In the case that none of the CPUs 51a, 51b completes the setting of the reaction force reference value θns in this manner, the timeout condition is met in time (step 106: Yes), causing the steering CPU to transition to the function stop state.

[0068] Subsequently, in the case where the setting of the reaction force reference value θns has been completed by each of the CPUs 51a, 51b and thus the setting of the reaction force reference value θns has been completed in both systems (step 206: Yes), the reaction force CPU ends the processing and completes the steering angle correction processing on the reaction force side. Thereafter, a notification of completion of the processing on the reaction force side is provided to the steering CPU via the local network 49.

[0069] On the other hand, in the case where the CPUs 51a, 51b include a CPU in a system where the setting of the reaction force reference value θns has not been completed and the CPUs 51a, 51b include a CPU in a system where the setting of the reaction force reference value θns has been completed (step 206: No), the reaction force CPU performs a state coordination process (step 208). The state coordination process is a coordination process for performing coordination so that the reaction force CPUs (i.e., each of the CPUs 51a, 51b) can perform the control information setting process (step 204) including the learning process again. For example, the state coordination process includes a process for keeping the CPU in the reaction force CPU and in the system where the setting of the reaction force reference value θns has been completed in a setting completed state, and causing the CPU to perform the learning process again together with the CPU in another system. Alternatively, the state coordination process may include a process for clearing the reaction force reference value θns set by the CPU in the reaction force CPU and in the system where the setting of the reaction force reference value θns has been completed. In this case, the CPU in the system in which the setting of the reaction force reference value θns has been completed among the reaction force CPUs is placed in a state in which the setting of the reaction force reference value θns has not been completed, and thus becomes able to perform the learning process again together with the CPU in the other system. Thereafter, the reaction force CPU repeatedly performs the control information setting process, i.e., step 204 and subsequent processes. Also in this case, the reaction force CPU may repeat step 204 and subsequent processes until the timeout condition is satisfied (step 106: Yes).

[0070] Rudder angle correction processing on the steering side

[0071] like Figure 5 As shown, in the steering angle correction process on the steering side, the steering CPU determines whether it is necessary to perform the steering angle correction process (step 302). In step 302, in the case where the steering CPU cannot read the steering reference value θnt in the initial check process (step 100), the steering CPU determines that it is necessary to perform the steering angle correction process. In the case where the steering reference value θnt has not been internally set, the steering CPU cannot read the steering reference value θnt in the initial check process. For example, in a state after the battery 47 is disassembled and replaced, the steering reference value θnt has not been internally set. Similarly, in a state after a read abnormality or a write abnormality occurs regarding the steering reference value θnt, the steering reference value θnt has not been internally set.

[0072] Subsequently, in the case where the steering CPU can read the steering reference value θnt in the initial check process (step 100) and therefore there is no need to perform the rudder angle correction process (step 302: No), the steering CPU ends the process and completes the rudder angle correction process on the steering side. The notification of the completion of the process on the steering side is provided to the reaction force CPU via the local network 49. In the case where both the completion of the process on the steering side and the notification of the completion of the rudder angle correction process on the reaction force side are satisfied and received from the reaction force CPU, the steering CPU can make a determination of "Yes" in step 102.

[0073] On the other hand, in the case where the steering CPU cannot read the steering reference value θnt in the initial check process (step 100) and therefore it is necessary to perform the rudder angle correction process (step 302: Yes), the steering CPU performs a control information setting process (step 304). In step 304, the control information setting process performed by the steering CPU includes a process of referring to the rotation angle θb. The steering CPU includes a process of referring to the pinion absolute rotation angle θabp. The control information setting process on the steering side includes a rotation angle correction process in which each CPU of the steering CPU corrects the rotation angle θb by referring to the pinion absolute rotation angle θabp as correction information.

[0074] For example, Figure 7 As shown, the rotation angle correction process includes a process of calculating the number of rotations corresponding to the pinion absolute rotation angle θabp. The rotation angle correction process includes a process of calculating a correction pinion angle θpc obtained by correcting the rotation angle θb to an absolute rotation angle as an integrated rotation angle based on the number of rotations. The rotation angle correction process includes a process of calculating a value of the correction pinion angle θpc corresponding to the rack neutral position as a steering midpoint value θct. The steering midpoint value θct obtained in this way is written and set as a steering reference value θnt by the steering CPU (i.e., by each of the CPUs 61a, 61b).

[0075] Subsequently, the steering CPU determines whether the setting of the steering reference value θnt has been completed in both systems (step 306). In step 306, the steering CPU determines whether the setting of the steering reference value θnt has been completed by each of the CPUs 61a, 61b. In addition, the steering CPU determines whether there is a CPU in a system in which the setting of the steering reference value θnt has not been completed and there is a CPU in a system in which the setting of the steering reference value θnt has been completed. During the rotation angle correction processing, as a result of the rotation angle correction processing, the CPUs 61a, 61b provide each other with a notification of the completion of the setting of the steering reference value θnt through inter-microcomputer communication or the like.

[0076] When none of the CPUs 61a, 61b completes the setting of the steering reference value θnt, the steering CPU does not execute step 306. In the case that none of the CPUs 61a, 61b completes the setting of the steering reference value θnt in this manner, the timeout condition is met in time (step 106: Yes), causing the steering CPU to transition to the function stop state.

[0077] Subsequently, in the case where the setting of the steering reference value θnt has been completed by each of the CPUs 61a, 61b and thus the setting of the steering reference value θnt has been completed in both systems (step 306: Yes), the steering CPU ends the processing and completes the steering angle correction processing on the steering side. Thereafter, a notification of the completion of the processing on the steering side is provided to the reaction force CPU via the local network 49.

[0078] On the other hand, in the case where the CPUs 61a, 61b include a CPU in a system where the setting of the steering reference value θnt has not been completed and the CPUs 61a, 61b include a CPU in a system where the setting of the steering reference value θnt has been completed (step 306: No), the steering CPU performs control information coordination processing (step 308). The control information coordination processing is a coordination processing for coordinating the CPU in the steering CPU and in the system where the setting of the steering reference value θnt has not been completed so that the steering reference value θnt can be set after the setting in the CPU in the system where the setting has been completed is completed. For example, the control information coordination processing includes a processing for sending the steering reference value θnt set by the CPU in the steering CPU and in the system where the setting of the steering reference value θnt has been completed to the CPU in the system where the setting of the steering reference value θnt has not been completed by means of inter-microcomputer communication or the like. The control information coordination processing includes a processing for completing the setting of the steering reference value θnt for the CPU by setting the steering reference value θnt for the CPU in the system where the setting of the steering reference value θnt has not been completed using the steering reference value θnt received by means of inter-microcomputer communication or the like. Thereafter, since each of the CPUs 61a, 61b has completed the setting of the steering reference value θnt, the steering CPU ends the processing and completes the steering angle correction processing on the steering side.

[0079] Operation of Embodiments

[0080] For example, Figure 6 As shown, the reaction force CPU sometimes encounters the following situation: CPUs 51a, 51b include CPUs in the system where the setting of the reaction force reference value θns has not been completed, and CPUs 51a, 51b include CPUs in the system where the setting of the reaction force reference value θns has been completed. Figure 6Part "(a)" shows the state of the main CPU 51a of the reaction force CPU. Figure 6 The portion "(b)" of FIG. 1 shows the state of the sub-CPU 51b of the reaction force CPU. In this example, in the middle of the learning process, for example, due to a temporary reduction in power, only the sub-CPU 51b of the reaction force CPU performs a reset operation.

[0081] Both CPUs 51a, 51b start the learning process, and thus rotate the steering wheel 3 in the right direction (step 402). Thereafter, only the sub-CPU 51b performs the reset operation, while the main CPU 51a continues the learning process normally.

[0082] As a result of continuing the learning process, the steering wheel 3 reaches the right limit position 3a, and therefore, the main CPU 51a temporarily stores the right limit position θrl (step 404a). On the other hand, the sub-CPU 51b performs a reset operation (step 404b), and thus terminates the learning process. Even when the sub-CPU 51b returns from the reset operation to a state where the sub-CPU 51b can perform the control information setting process thereafter (step 406b), the sub-CPU 51b cannot return to the learning process because the learning process is terminated. That is, the sub-CPU 51b cannot complete the learning process (i.e., the control information setting process), and provides an incomplete notification to the main CPU 51a through inter-microcomputer communication, etc.

[0083] The main CPU 51a further continues the learning process, and thus rotates the steering wheel 3 in the left direction (step 406a). In addition, the steering wheel 3 reaches the left limit position 3b, and therefore, the main CPU 51a temporarily stores the left limit position θll (step 408a), and calculates the reaction force midpoint value θcs (step 410a).

[0084] Thereafter, the main CPU 51a completes the setting of the reaction force reference value θns (step 412a). On the other hand, the sub-CPU 51b has not completed the setting of the reaction force reference value θns (step 412b). Thus, there is a sub-CPU 51b that has not completed the setting of the reaction force reference value θns, while there is a main CPU 51a that has completed the setting of the reaction force reference value θns, and therefore, the reaction force CPU makes a determination of "No" in step 206 (step 414). Thereafter, by executing the state coordination processing, the reaction force CPU performs coordination so that each CPU can perform the control information setting processing including the learning processing again.

[0085] In this way, even in the case where there is a CPU in the system for which the setting of the reaction force reference value θns has not been completed, the reaction force CPU can complete the setting of the reaction force reference value θns in the CPUs in all the systems through the state coordination processing.

[0086] Similarly, for example, Figure 7 As shown, the steering CPU sometimes encounters the following situation: the CPUs 61a, 61b include the CPU in the system where the setting of the steering reference value θnt has not been completed, and at the same time, the CPUs 61a, 61b include the CPU in the system where the setting of the steering reference value θnt has been completed. Figure 7 Part "(a)" of FIG. 1 shows the state of the main CPU 61a which is the steering CPU. Figure 7 Part "(b)" shows the state of the sub-CPU 61b of the steering CPU. In this example, in the rotation angle correction processing, for example, due to failure of the reference rotation angle θb or the pinion absolute rotation angle θabp, only the sub-CPU 61b of the steering CPU cannot continue the rotation angle correction processing.

[0087] Each of the CPUs 61a, 61b starts the rotation angle correction processing, and thus refers to the pinion absolute rotation angle θabp (step 502a). Thereafter, as a result of continuing the rotation angle correction processing, the main CPU 61a calculates the correction pinion angle θpc obtained by correcting the rotation angle θb based on the number of rotations corresponding to the pinion absolute rotation angle θabp (step 504a).

[0088] On the other hand, the sub-CPU 61b fails to refer to the rotation angle θb or the pinion absolute rotation angle θabp (step 502b), and thus terminates the rotation angle correction processing. Thereafter, the sub-CPU 61b provides the main CPU 61a with a notification that the rotation angle correction processing (i.e., the control information setting processing) is not completed through inter-microcomputer communication or the like.

[0089] The main CPU 61a further continues the rotation angle correction processing. Therefore, the main CPU 61a calculates the steering midpoint value θct (step 506a), and completes the setting of the steering reference value θnt (step 508a). On the other hand, the sub-CPU 61b has not completed the setting of the steering reference value θnt (step 508b). Thus, there is a sub-CPU 61b that has not completed the setting of the steering reference value θnt, while there is a main CPU 61a that has completed the setting of the steering reference value θnt, and therefore, the steering CPU makes a "no" determination in step 306 (step 510). Thereafter, by executing the control information coordination processing, the steering CPU performs coordination so that the sub-CPU 61b can set the steering reference value θnt after the setting is completed in the main CPU 61a.

[0090] In this manner, even in the case where there is a CPU in a system for which setting of the steering reference value θnt has not been completed, the steering CPU can complete setting of the steering reference value θnt in the CPUs in all the systems through the control information coordination process.

[0091] Effects of implementation methods

[0092] (1-1) Even in the case where there is a CPU in a system in which the setting of the reaction force reference value θns has not been completed, the reaction force CPU can complete the setting of the reaction force reference value θns in the CPUs in all systems through state coordination processing. The same is true for the steering CPU. That is, the steering CPU can complete the setting of the steering reference value θnt in the CPUs in all systems through control information coordination processing. Thus, in the reaction force CPU and the steering CPU, it is possible to suppress the occurrence of a situation in which it is impossible to determine whether the setting of the corresponding reference values ​​θns, θnt has been completed in both systems and the event is endlessly repeated. Therefore, it is possible to suppress the extension of the period after the power source of the vehicle steering system 2 is turned on and before the control of the steering operation of the vehicle can be performed.

[0093] (1-2) Through the state coordination processing, the reaction force CPU can cause the CPU in the system in which the setting of the reaction force reference value θns has been completed to execute the control information setting processing including the learning processing again. Thus, each of the CPUs 51a, 51b in all systems can be caused to execute the control information setting processing again regardless of whether the setting of the reaction force reference value θns has been completed.

[0094] (1-3) In the reaction force CPU, even in the case where each of the CPUs 51a, 51b of the reaction force control unit 50 sets the reaction force reference value θns by rotating the steering wheel 3, the CPUs in all systems can perform the control information setting process again. That is, the occurrence of an event in which the steering wheel 3 cannot be rotated due to a difference in the internal state between the CPUs 51a, 51b can be suppressed.

[0095] (1-4) Through the control information coordination processing, the steering CPU can use the steering reference value θnt after the setting in the CPU in the system where the setting of the steering reference value θnt has been completed, and also complete the setting of the steering reference value θnt in the CPU in the system where the setting of the steering reference value θnt has not been completed. Thus, when there is a CPU in the system where the setting of the steering reference value θnt has been completed, the setting of the steering reference value θnt can be completed in the CPUs in all the systems.

[0096] (1-5) Through the control information coordination processing, the steering CPU can complete the setting of the steering reference value θnt in the CPUs 61a, 61b of the steering control unit 60. Thus, even in the case where each of the CPUs 61a, 61b sets the steering reference value θnt by correcting the rotation angle θb using the pinion absolute rotation angle θabp, the CPUs in all systems can complete the setting of the steering reference value θnt. That is, even when the CPUs 61a, 61b include a CPU in a system that fails to acquire the rotation angle θb or the pinion absolute rotation angle θabp, it is possible to quickly cope with it.

[0097] Other Implementations

[0098] The above embodiments may be modified as follows. In addition, the following other embodiments may be combined with each other within the scope without technical inconsistency.

[0099] In the control information setting process on the reaction force side, the control information coordination process in the control information setting process on the steering side may be performed instead of the state coordination process. Alternatively, in the control information setting process on the reaction force side, the control information coordination process may be performed while repeatedly performing the state coordination process.

[0100] In the control information setting process on the steering side, the state coordination process in the control information setting process on the reaction force side can be performed instead of the control information coordination process. In this case, in the control information setting process on the steering side, the control information coordination process can be performed while repeatedly performing the state coordination process.

[0101] The control information setting process only needs to be configured so that at least the state coordination process is performed in the control information setting process on the reaction force side. That is, the control information setting process on the steering side can be configured so that the control information coordination process is not performed. In other embodiments of the description, the steering control unit 60 can be composed of a single system.

[0102] The control information setting process only needs to be configured so that at least the control information coordination process is performed in the control information setting process on the steering side. That is, the control information setting process on the reaction force side can be configured so that the state coordination process is not performed. In other embodiments of the description, the reaction force control unit 50 can be composed of a single system.

[0103] The method for internally setting the reaction force reference value θns is not limited to the method of performing the learning operation, and may be changed when appropriate, such as to a method in which the setting is performed manually by a worker. The learning process may be a process of first rotating the steering wheel 3 in the left direction and then rotating the steering wheel 3 in the right direction.

[0104] The learning process only needs to include a process of temporarily storing one of the respective limit positions θrl, θll. That is, the process regarding the learning operation may not include a process of temporarily storing the other of the respective limit positions θrl, θll. For example, in the case of a process including temporarily storing the right limit position θrl, the reaction force CPU may calculate a value obtained by subtracting a value of half the rotation range between the right limit position 3a and the left limit position 3b from the right limit position θrl as the reaction force midpoint value θcs.

[0105] The learning process may include a process of determining the effectiveness of the reaction force midpoint value θcs.

[0106] In the learning process, it is only necessary to monitor at least the currents iu1, iv1, iw1 to determine that the steering wheel 3 reaches the limit positions 3a, 3b. Alternatively, in addition to the above embodiment, other parameters may be considered to determine that the steering wheel 3 reaches the limit positions 3a, 3b. Examples of other parameters may include the amount of change in the currents iu1, iv1, iw1, the amount of change in the angular velocity ωs, and the time from the start of the rotation of the steering wheel 3.

[0107] The displacement amount of the steering wheel 3 is not limited to the amount calculated based on the integral processing of the rotation angle θa. For example, the detection value of the steering angle sensor that directly detects the rotation angle of the steering shaft 11 can be used. For example, the steering angle sensor can be provided in the steering shaft 11 between the steering wheel 3 and the torque sensor 41.

[0108] In addition to the steering steering angle θs, in the case of using the above-mentioned rudder angle sensor, in the control information setting process on the reaction force side instead of the learning process, each CPU of the reaction force CPU can perform a rotation angle correction process of correcting the rotation angle θa by referring to the detection result of the rudder angle sensor. In other embodiments of the description, in the control information setting process on the reaction force side, the control information coordination process in the control information setting process on the steering side can be performed instead of the state coordination process.

[0109] In the control information setting process on the steering side instead of the rotation angle correction process, each CPU of the steering CPU may perform a learning process of acquiring a value by moving the rack shaft 22 (i.e., the steering wheel 5) in the right and left directions to the corresponding rack end 25. In other embodiments of the description, in the control information setting process on the steering side, the state coordination process in the control information setting process on the reaction force side may be performed instead of the control information coordination process.

[0110] The number of systems of the reaction force control unit 50 may be three or more. Even in this case, the above embodiment can be applied. The same is true for the number of systems of the steering control unit 60.

[0111] The steering actuator 12 does not need to include the steering-side speed reduction mechanism 14. The reaction force motor 13 is not limited to a three-phase brushless motor. For example, a DC motor with brushes may be used. The other embodiments described above may be similarly applied to the steering motor 32.

[0112] The pinion angle θp can be obtained by converting the detection value of the movement amount of the rack shaft 22. In this case, the controlled variable and the like related to the pinion angle θp are converted by the detection value of the movement amount of the rack shaft 22.

[0113] The operating member operated by the driver to steer the vehicle is not limited to the steering wheel 3. For example, a joystick may be employed.

[0114] The steering unit 6 transmits the rotation of the steering motor 32 to the conversion mechanism 34 through the transmission mechanism 33, but is not limited thereto, and for example, the steering unit 6 may be configured to transmit the rotation of the steering motor 32 to the conversion mechanism 34 through a gear mechanism. In addition, the steering unit 6 may be configured so that the steering motor 32 directly rotates the conversion mechanism 34. In addition, the steering unit 6 may be configured to include a second rack and pinion mechanism, and the steering unit 6 may be configured so that the second rack and pinion mechanism converts the rotation of the steering motor 32 into the reciprocating motion of the rack shaft 22.

[0115] The steering unit 6 is not limited to the configuration in which the steering wheel 5 on the right and the steering wheel 5 on the left are interlocked. In other words, the steering wheel 5 on the right and the steering wheel 5 on the left can be independently controlled.

[0116] In the above embodiment, the vehicle steering system 2 has a linkless structure in which the steering unit 4 and the steering unit 6 are always mechanically separated, but is not limited thereto, and may have a structure in which the steering unit 4 and the steering unit 6 can be mechanically separated by a clutch, for example. In addition, the vehicle steering system 2 is not limited to a steer-by-wire type steering device, and may include an electric power steering device in which the torque of a motor is given to the steering shaft 11 or the rack shaft 22.

Claims

1. A steering control device (1) for use in a vehicle steering system (2) for steering a vehicle, The steering control device (1) is characterized by comprising a rudder angle control unit (50, 60), the rudder angle control unit (50, 60) being configured to perform control with reference to a rudder angle variable obtained in relation to the steering, wherein: The rudder angle control unit (50, 60) is configured to perform a control information setting process of setting control information, the control information being a value indicating a straight-line movement of the vehicle and being a reference of the rudder angle variable; In the control information setting process, the steering angle control unit (50, 60) completes the setting of the control information after the power source of the vehicle steering system (2) is turned on, so that the steering control of the vehicle can be performed; The rudder angle control unit (50, 60) comprises a control circuit (51a, 51b, 61a, 61b), wherein the control circuit (51a, 51b, 61a, 61b) is configured to control the rudder angle variables in coordination with each other; The control circuit (51a, 51b, 61a, 61b) is configured to perform steering operation on the travel of the vehicle under the condition that the setting of the control information has been completed in all the control circuits in the control circuit (51a, 51b, 61a, 61b) during the execution of the control information setting process; and The control information setting process includes the following coordination process: when the setting of the control information has been completed in the first control circuit group in the control circuit (51a, 51b, 61a, 61b) but the setting of the control information has not been completed in the second control circuit group in the control circuit (51a, 51b, 61a, 61b), coordination is performed so that all control circuits in the control circuit (51a, 51b, 61a, 61b) can complete the setting of the control information.

2. The steering control device (1) according to claim 1, characterized in that: The coordination process includes a state coordination process of: coordinating the state of the first control circuit group so that each control circuit in the first control circuit group transitions to a state capable of executing the control information setting process again; and The first control circuit group is configured so that each control circuit in the first control circuit group executes the control information setting process again after coordination by the state coordination process.

3. The steering control device (1) according to claim 2, characterized in that: The vehicle steering system (2) includes a dynamic power transmission path cut off between a steering unit (4) and a steering unit (6), wherein the steering unit (4) is steered by a steering wheel (3) of the vehicle and the steering unit (6) is operated to steer a steering wheel (5) of the vehicle; The rudder angle control unit (50, 60) comprises a reaction force control unit (50), and the reaction force control unit (50) comprises a first control circuit (51a, 51b); The reaction force control unit (50) is configured to control the operation of the steering unit (4) by referring to a steering manipulated variable, so that a steering manipulation reaction force is given to the steering wheel (3), the steering manipulated variable being the rudder angle variable obtained from the steering unit (4) in relation to the steering manipulation; Each of the first control circuits (51a, 51b) of the reaction force control unit (50) is configured to perform the control information setting process based on corresponding values ​​acquired when the steering wheel (3) is rotated to the extreme positions in the first direction and the second direction; and Each of the first control circuits (51a, 51b) of the reaction force control unit (50) is configured to execute the state coordination process in the control information setting process.

4. The steering control device (1) according to claim 1, characterized in that: The coordination process includes the following control information coordination process: coordinating the second control circuit group so that the setting of the control information is completed by setting the control information using the control information after the setting in the first control circuit group is completed; and The control circuits (51a, 51b, 61a, 61b) are configured so that the setting of the control information is completed in all the control circuits in the control circuits (51a, 51b, 61a, 61b) after coordination through the control information coordination process.

5. The steering control device (1) according to claim 4, characterized in that: The vehicle steering system (2) includes a dynamic power transmission path cut off between a steering unit (4) and a steering unit (6), wherein the steering unit (4) is steered by a steering wheel (3) of the vehicle and the steering unit (6) is operated to steer a steering wheel (5) of the vehicle; The steering angle control unit (50, 60) comprises a steering control unit (60), and the steering control unit (60) comprises a second control circuit (61a, 61b); The steering control unit (60) is configured to control the operation of the steering unit (6) by referring to a steering variable, so that a steering force is given to the steering wheel (5), wherein the steering variable is the rudder angle variable obtained from the steering unit (6) in relation to the steering manipulation; Each of the second control circuits (61a, 61b) of the steering control unit (60) is configured to perform the control information setting process by correcting the steering variable using a correction variable acquired from the steering unit (6) in addition to the steering variable; and Each of the second control circuits (61a, 61b) of the steering control unit (60) is configured to execute the control information coordination process in the control information setting process.

6. The steering control device (1) according to claim 1, characterized in that: The vehicle steering system (2) includes a dynamic power transmission path cut off between a steering unit (4) and a steering unit (6), wherein the steering unit (4) is steered by a steering wheel (3) of the vehicle and the steering unit (6) is operated to steer a steering wheel (5) of the vehicle; The steering angle control unit (50, 60) comprises: a reaction force control unit (50), the reaction force control unit (50) comprising a first control circuit (51a, 51b); and a steering control unit (60), the steering control unit (60) comprising a second control circuit (61a, 61b); The reaction force control unit (50) is configured to control the operation of the steering unit (4) by referring to a steering manipulation variable obtained from the steering unit (4) regarding the steering manipulation, so that a steering manipulation reaction force is given to the steering wheel (3); The steering control unit (60) is configured to control the operation of the steering unit (6) by referring to the steering variable obtained from the steering unit (6) regarding the steering manipulation, so that a steering force is given to the steering wheel (5); The coordination process includes: state coordination processing: coordinating the state of the first control circuit group so that each control circuit in the first control circuit group transitions to a state capable of executing the control information setting processing again, and Control information coordination processing: Coordinating the second control circuit group so that the setting of the control information is completed by setting the control information using the control information after the setting in the first control circuit group is completed; Each of the first control circuits (51a, 51b) of the reaction force control unit (50) is configured to perform the state coordination process in the control information setting process; Each of the first control circuits (51a, 51b) is configured to, in the case of executing the state coordination process, execute the control information setting process again after coordination by the state coordination process; Each of the second control circuits (61a, 61b) of the steering control unit (60) is configured to perform the control information coordination process in the control information setting process; and The second control circuit (61a, 61b) is configured so that, in the case where the control information coordination process is performed, the setting of the control information is completed in all the control circuits in the control circuit after coordination is performed by the control information coordination process.

7. A steering control method for a vehicle steering system (2) for steering a vehicle, The steering control method is characterized by comprising the following rudder angle control processing: performing control with reference to a rudder angle variable obtained in relation to the steering, wherein: The steering angle control process includes setting control information, the control information being a value indicating a straight-line movement of the vehicle and being a reference for the steering angle variable; Setting the control information by completing the setting of the control information after the power source of the vehicle steering system (2) is turned on, so that the steering control of the vehicle can be performed; The rudder angle control process includes a process performed by a control circuit (51a, 51b, 61a, 61b), and the control circuits (51a, 51b, 61a, 61b) are configured to control the rudder angle variables in coordination with each other; The processing performed by the control circuit (51a, 51b, 61a, 61b) enables control of steering operation of the travel of the vehicle under the condition that the setting of the control information in all the control circuits in the control circuit (51a, 51b, 61a, 61b) has been completed; and Setting the control information includes: when the setting of the control information has been completed in the first control circuit group in the control circuit (51a, 51b, 61a, 61b) but the setting of the control information has not been completed in the second control circuit group in the control circuit (51a, 51b, 61a, 61b), performing coordination so that all control circuits in the control circuit (51a, 51b, 61a, 61b) can complete the setting of the control information.

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