Steering control system and steering control method

Abstract

A steering control system that controls a steering device (2) of a vehicle includes a storage unit and a control unit configured to make a state transition from a start-up state to a normal control state after a power supply system of the vehicle is started up. In the start-up state, the control unit performs a correction information storage process that acquires correction factor information using a state variable obtained from the steering device (2) and writes correction information obtained based on the correction factor information into the storage unit. The control unit is configured to perform an abnormal condition determination process that determines whether an abnormal condition indicating an abnormality of the correction information is satisfied in the start-up state. When the abnormal condition is satisfied, the correction information storage process is re-executed. The abnormal condition determination process is executed at least before the correction information storage process or after the correction information storage process.

Description

Background Technology 1. Technical Field

[0002] This invention relates to a steering control system and a steering control method.

[0003] 2. Description of related technologies

[0004] For example, Japanese Unexamined Patent Application Publication No. 2021-195086 (JP 2021-195086 A) describes a steer-by-wire device installed in a vehicle. The steer-by-wire device has a structure in which the power transmission path between the vehicle's steering wheel and the vehicle's turning wheels is interrupted. This steer-by-wire device includes a steering control system that controls the steering mechanism as a target.

[0005] In this steering control system, the steering angle midpoint information, used as a reference when calculating the steering angle of the steering wheel for control, is stored in memory. However, for example, when the battery is removed from the vehicle, the steering angle midpoint information already stored in memory may be lost. The steering control system is configured to re-execute the process of storing the steering angle midpoint information in memory when it has been lost. Summary of the Invention

[0006] As described above, when the steering angle midpoint information is stored in memory again, for example, due to an anomaly during the writing process or an initial anomaly in the writing of the steering angle midpoint information, an anomaly may occur in the memory. When an anomaly occurs in the memory, the steering angle of the steering wheel to be used for control will be obtained only by referring to the abnormal steering angle midpoint information. This leads to a deviation from the actual state of the steering device.

[0007] According to a first aspect of the invention, a steering control system controls the steering mechanism of a vehicle. The steering mechanism has a structure in which the power transmission path between a steering unit having an operating member and a rotating unit configured to rotate a rotating wheel is interrupted. The steering control system has a storage unit and a control unit. The storage unit stores information related to the control of the steering mechanism, and the control unit is configured to perform a state transition from a starting state to a normal control state after the vehicle's power system is started. The starting state is a state in which the control unit performs correction information storage processing. This correction information storage processing uses state variables obtained from the steering mechanism to acquire correction element information, and further writes correction information obtained based on the acquired correction element information into the storage unit. The normal control state is a state in which the control unit performs normal processing, which controls the steering mechanism using control variables obtained by correcting state variables based on the correction information. The control unit is configured to perform an abnormal condition determination process in the starting state. This abnormal condition determination process determines whether an abnormal condition is met, and the abnormal condition indicates that the correction information already written into the storage unit through the correction information storage process is abnormal. The correction information storage process is a process that is re-executed when the abnormal condition is met. Abnormal condition determination processing is a process that is performed at least before or after the correction information storage processing.

[0008] The steering control method according to a second aspect of the invention is a method for controlling a vehicle's steering device. The steering device has a structure in which the power transmission path between a steering unit having operating members and a rotating unit configured to rotate a rotating wheel is interrupted. The steering control method includes storing information related to the control of the steering device, and performing a state transition from a starting state to a normal control state after the vehicle's power system is started. The starting state is a state in which correction information storage processing is performed, which uses state variables obtained from the steering device to acquire correction element information, and further stores correction information obtained based on the acquired correction element information. The normal control state is a state in which normal processing is performed, which controls the steering device using control variables obtained by correcting state variables based on the correction information. The method includes performing an abnormal condition determination process in the starting state, which determines whether an abnormal condition is met, the abnormal condition indicating that the correction information stored by the correction information storage process is abnormal. The correction information storage process is a process that is re-executed when an abnormal condition is met. The abnormal condition determination process is a process that is performed at least before or after the correction information storage process.

[0009] In the configuration and method described above, even if the correction information written in the storage unit is abnormal in the startup state, the control unit can use the correct correction information by re-executing the correction information storage process. Therefore, the control unit can create a situation where state variables can be corrected based on the correction information. Thus, the control variables are less likely to deviate from the actual state of the steering device.

[0010] In the steering control system according to the aspects described above, the control unit can be configured to perform anomaly information storage processing in the starting state. This anomaly information storage processing writes anomaly condition information to the storage unit when writing correction information to the storage unit cannot be completed. Anomaly condition determination processing can be a process performed before the correction information storage processing, and can include processing that determines whether an anomaly condition is met after the anomaly condition information has been written to the storage unit.

[0011] In this configuration, even if the writing of calibration information to the storage unit fails, the calibration information storage process can be re-executed when the vehicle's power system is restarted next time. Therefore, the control unit can correct the state variables based on the correct calibration information.

[0012] In the steering control system according to the aspects described above, the control unit can be configured to perform a battery replacement condition determination process during startup. This process determines whether battery replacement conditions are met, indicating the state after the battery belonging to the vehicle's power system has been removed and replaced. The correction information storage process can be executed when the battery replacement conditions are met, or it can be not executed when the battery replacement conditions are not met. The abnormal condition determination process can be executed before the battery replacement condition determination process.

[0013] In this configuration, calibration information storage processing is performed even when abnormal conditions are met, thus eliminating the need for calibration information storage processing. During startup, the control unit can appropriately respond to abnormalities in the storage unit related to calibration information already written to it through the calibration information storage processing. Therefore, the reliability and accuracy of the calibration information can be improved.

[0014] In a steering control system according to the aspects described above, the steering device may include sensors that detect actual measured values ​​corresponding to control variables obtained through correction based on correction information. Abnormal condition determination processing may be a process performed after correction information storage processing, and may include processing to determine whether an abnormal condition is met based on a comparison of the control variables obtained through correction based on the correction information with the actual measured values ​​obtained from the sensors.

[0015] In this configuration, even if the correction information obtained through the correction information storage process performed during the startup state period is not a normal value, the correction information storage process can be re-executed during the same startup state period. Therefore, the control unit can correct the state variables based on the correct correction information.

[0016] In the steering control system according to the aspects described above, the correction information may include steering-side correction information and rotation-side correction information. Steering-side correction information may be information used to correct control variables used for steering when controlling the steering unit, and rotation-side correction information may be information used to correct control variables used for rotation when controlling the rotation unit. Correction information storage processing may include steering-side correction information storage processing and rotation-side correction information storage processing. Steering-side correction information storage processing may be a process of acquiring steering-side correction element information using state variables obtained from the steering unit and further writing steering-side correction information obtained based on the acquired steering-side correction element information into a storage unit. Rotation-side correction information storage processing may be a process of acquiring rotation-side correction element information using state variables obtained from the rotation unit and further writing rotation-side correction information obtained based on the acquired rotation-side correction element information into a storage unit. Abnormal condition determination processing may include a process of determining whether abnormal conditions indicating abnormal steering-side correction information already written into the storage unit through steering-side correction information storage processing are met, and a process of determining whether abnormal conditions indicating abnormal rotation-side correction information already written into the storage unit through rotation-side correction information storage processing are met.

[0017] In this configuration, the steering control system can correct the state variables related to the steering unit and the turning unit, respectively. Therefore, the control variables used to control the steering unit and the turning unit separately are unlikely to deviate from the actual state of the respective units.

[0018] This invention can reduce the possibility of deviation from the actual state of the steering device. Attached Figure Description

[0019] The features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, in which the same reference numerals denote the same elements, and wherein:

[0020] Figure 1 This is a view showing the configuration of the steer-by-wire device according to the first embodiment;

[0021] Figure 2 It shows the result of Figure 1 A block diagram of the processes performed by the steering control system;

[0022] Figure 3 It shows Figure 1 A flowchart of the process performed by the steering control system in the starting state;

[0023] Figure 4 It shows Figure 3 A flowchart of the process for storing and processing steering side correction information;

[0024] Figure 5A It is shown in Figure 3 A view of the steering wheel's movement during the storage and processing of steering side correction information;

[0025] Figure 5B It is shown in Figure 3 Another view of the steering wheel's movement during the storage and processing of steering side correction information;

[0026] Figure 5C It is shown in Figure 3 Another view of the steering wheel's movement during the storage and processing of steering side correction information;

[0027] Figure 5D It is shown in Figure 3 Another view of the steering wheel's movement during the storage and processing of steering side correction information;

[0028] Figure 5E It is shown in Figure 3 Another view of the steering wheel's movement during the storage and processing of steering side correction information;

[0029] Figure 5F It is shown in Figure 3 Another view of the steering wheel's movement during the storage and processing of steering side correction information;

[0030] Figure 5G It is a graph showing the changes in the temporary steering angle θsi and the target steering angle θs*;

[0031] Figure 6 This is a flowchart illustrating the process of storing and processing rotational side correction information; and

[0032] Figure 7 This is a flowchart illustrating the process performed by the steering control system according to the second embodiment in the starting state. Detailed Implementation

[0033] First Implementation Method

[0034] The first embodiment of the present invention will now be described. For example... Figure 1As shown, the steering control device 1 (steering control system) controls the steering device 2 as the target. The steering device 2 is configured as a steer-by-wire vehicle steering device. The steering device 2 includes a steering unit 4 and a rotation unit 6. The steering unit 4 is steered by the driver via the vehicle's steering wheel 3, which serves as an operating member. The rotation unit 6 rotates the vehicle's left and right steering wheels 5 according to the steering input by the driver into the steering unit 4. The steering device 2 of this embodiment has, for example, a structure in which the power transmission path between the steering unit 4 and the rotation unit 6 is always mechanically cut off. In this structure, the power transmission path between the steering actuator 12, which will be described later, and the rotation actuator 31, which will be described later, is always mechanically cut off.

[0035] The steering unit 4 includes a steering shaft 11 and a steering actuator 12. The steering shaft 11 is connected to the steering wheel 3. An end 11a of the steering shaft 11, opposite to the side connected to the steering wheel 3, has a limiter mechanism 11b. The limiter mechanism 11b defines the rotation range of the steering shaft 11. Therefore, the rotation range of the steering wheel 3, which rotates integrally with the steering shaft 11, is defined by the limiter mechanism 11b. For example, the steering wheel 3 can rotate between a right-turning limit position 3a and a left-turning limit position 3b, which define the rotation range. The steering actuator 12 has a steering-side motor 13 as a drive source and a steering-side reduction mechanism 14. The steering-side motor 13 is a reaction force motor that applies a steering reaction force to the steering wheel 3 via the steering shaft 11; this steering reaction force is a force that reacts to steering. The steering-side motor 13 is connected to the steering shaft 11 via the steering-side reduction mechanism 14, which is formed, for example, by a worm gear. For example, a three-phase brushless motor is used as the steering-side motor 13 in this embodiment.

[0036] The rotating unit 6 includes a pinion shaft 21, a rack shaft 22 serving as a rotation axis, and a rack housing 23. The pinion shaft 21 and the rack shaft 22 are connected together at a predetermined cross angle. The pinion teeth 21a formed on the pinion shaft 21 and the rack teeth 22a formed on the rack shaft 22 mesh with each other to form a rack and pinion mechanism 24. Therefore, the pinion shaft 21 corresponds to a rotation axis, the angle of which can be converted into a rotation angle θi, which is the rotational position of the rotating wheel 5. The rack housing 23 houses the rack and pinion mechanism 24. One end of the pinion shaft 21, on the side opposite to the side connected 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. At both ends of the rack shaft 22, tie rods 26 are connected via rack ends 25 formed by ball joints. The front end of the tie rod 26 is connected to a steering knuckle (not shown), on which the left and right rotating wheels 5 are respectively mounted.

[0037] The rotation unit 6 includes a rotation actuator 31. The rotation actuator 31 includes a rotation-side motor 32 as a drive source, a transmission mechanism 33, and a conversion mechanism 34. The rotation-side motor 32 applies rotational force to the rack shaft 22 to rotate the rotating wheel 5 via the transmission mechanism 33 and the conversion mechanism 34. The rotation of the rotation-side motor 32 is transmitted to the conversion mechanism 34 via the transmission mechanism 33, which is, for example, a belt transmission mechanism. The transmission mechanism 33 converts the rotation of the rotation-side motor 32 into the reciprocating motion of the rack shaft 22 via the conversion mechanism 34, which is, for example, a ball screw mechanism. As the rotation-side motor 32 in this embodiment, for example, a three-phase brushless motor is used.

[0038] In the steering device 2 configured as described above, the rotation angle θi of the rotating wheel 5 is changed when the motor torque is applied as a rotational force from the rotary actuator 31 to the rack shaft 22 according to the driver's steering operation. Simultaneously, a steering reaction force acting on the driver's steering is applied from the steering actuator 12 to the steering wheel 3. Therefore, in the steering device 2, the steering torque Th required to steer the steering wheel 3 is changed by the steering reaction force, which is the motor torque applied from the steering actuator 12.

[0039] The reason for providing the pinion shaft 21 is to support the rack shaft 22 together with the pinion shaft 21 inside the rack housing 23. The rack shaft 22 is supported by a support mechanism (not shown) provided in the steering device 2, allowing it to move in its axial direction and being pressed against the pinion shaft 21. Therefore, the rack shaft 22 is supported inside the rack housing 23. However, the rack shaft 22 can be supported in the rack housing 23 without using another support mechanism for the pinion shaft 21.

[0040] Electrical configuration of steering system

[0041] like Figure 1 As shown, the steering-side motor 13 and the rotation-side motor 32 are connected to the steering control device 1. The steering control device 1 controls the operation of the steering-side motor 13 and the rotation-side motor 32.

[0042] The detection results from various sensors are input into the steering control unit 1. Various sensors are connected to the steering control unit 1. These sensors include, for example, a torque sensor 41, a steering-side rotation angle sensor 42, a turning-side rotation angle sensor 43, a vehicle speed sensor 44, and a pinion absolute angle sensor 45.

[0043] Torque sensor 41 detects steering torque Th, which is the value indicating the torque applied to steering shaft 11 by the driver's steering operation. Steering-side rotation angle sensor 42 detects rotation angle θa, which is the angle of the rotation shaft of steering-side motor 13 within a 360° range. Rotation-side rotation angle sensor 43 detects rotation angle θb, which is the angle of the rotation shaft of rotation-side motor 32 within a 360° range. Vehicle speed sensor 44 detects vehicle speed V, which is the vehicle's travel speed. Pinion absolute angle sensor 45 detects pinion absolute rotation angle θabp, which is the actual measured angle value of the rotation axis of pinion shaft 21 within a range exceeding 360°.

[0044] Specifically, the torque sensor 41 is mounted on the steering shaft 11 at a location closer to the steering wheel 3 than the steering-side deceleration mechanism 14. The torque sensor 41 detects the steering torque Th based on the torsion of the torsion bar 41a located in the middle portion of the steering shaft 11. For example, when the vehicle turns right, the steering torque Th is detected as a positive value, while when the vehicle turns left, the steering torque Th is detected as a negative value.

[0045] A steering-side rotation angle sensor 42 is installed at the steering-side motor 13. The rotation angle θa of the steering-side motor 13 is used to calculate the steering angle θs. The steering-side motor 13 and the steering shaft 11 operate in coordination with each other via the steering-side reduction mechanism 14. Therefore, there is a correlation between the rotation angle θa of the steering-side motor 13 and the rotation angle of the steering shaft 11. Furthermore, there is a correlation between the rotation angle θa of the steering-side motor 13 and the steering angle θs, which is the rotation angle indicating the rotational position of the steering wheel 3. Therefore, the steering angle θs can be calculated based on the rotation angle θa of the steering-side motor 13. For example, when the vehicle turns right, the rotation angle θa is detected as a positive value, while when the vehicle turns left, the rotation angle θa is detected as a negative value.

[0046] A rotation angle sensor 43 is installed at the rotation side motor 32. The rotation angle θb of the rotation side motor 32 is used to calculate the pinion angle θp. The rotation side motor 32 and the pinion shaft 21 cooperate with each other through the transmission mechanism 33, the conversion mechanism 34, and the rack and pinion mechanism 24. Therefore, there is a correlation between the rotation angle θb of the rotation side motor 32 and the pinion angle θp, which is the rotation angle of the pinion shaft 21. Thus, the pinion angle θp can be obtained based on the rotation angle θb of the rotation side motor 32. The pinion shaft 21 meshes with the rack shaft 22. Therefore, there is also a correlation between the pinion angle θp and the amount of movement of the rack shaft 22. The pinion angle θp is angular information indicating the rotation state of the rotating wheel 5 and is a value reflecting the rotation angle θi, which is the rotation position of the rotating wheel 5. For example, when the vehicle turns right, the rotation angle θb is detected as a positive value, while when the vehicle turns left, the rotation angle θb is detected as a negative value.

[0047] A pinion absolute angle sensor 45 is mounted on the pinion shaft 21. The absolute rotation angle θabp of the pinion on the pinion shaft 21 is used to calculate the pinion angle θp. For example, when the vehicle turns right, the absolute rotation angle θabp is detected as a positive value, while when the vehicle turns left, the absolute rotation angle θabp is detected as a negative value. In this embodiment, the pinion absolute angle sensor 45 is an example of a sensor that detects the actual measured value of the pinion angle θp.

[0048] The power system 46 is connected to the steering control unit 1. The power system 46 has a battery 47. The battery 47 is a secondary battery installed in the vehicle and serves as a power source for supplying power to the steering-side motor 13 and the steering-side motor 32 for operation. In addition, the battery 47 serves as a power source for supplying power to the steering control unit 1 for operation.

[0049] Vehicle start switch 48 ( Figure 1A switch (e.g., an ignition switch) is positioned between the steering control unit 1 and the battery 47. In the two power supply lines L1 and L2 connecting the steering control unit 1 and the battery 47, a starter switch 48 is positioned at the midpoint of the power supply line L2 branching off from the power supply line L1. The starter switch 48 is activated when various functions are engaged to operate the vehicle's driving source (e.g., the engine) and to allow vehicle operation. The operation of the starter switch 48 switches the power supply line L2 on and off. In this embodiment, the operating state of the steering unit 2 is associated with the operating state of the vehicle. As for the power supply line L1, its conduction is essentially always continuous, and is indirectly switched on and off depending on the operating state of the steering unit 2 as a function of the steering unit 2. The operating state of the steering unit 2 is associated with the on and off states of the power supply lines L1 and L2, which are the power supply states of the battery 47.

[0050] Steering control function

[0051] The steering control unit 1 includes a central processing unit (hereinafter referred to as "CPU") 49a and a memory 49b. When the CPU 49a executes a program stored in the memory 49b at predetermined arithmetic operation cycles, the steering control unit 1 performs various processes. The CPU 49a and the memory 49b constitute a microcomputer as processing circuitry. The memory 49b includes computer-readable media, such as random access memory (RAM) and read-only memory (ROM). However, implementing various processes via software is one example. The processing circuitry belonging to the steering control unit 1 can be configured such that at least some of the processes are implemented by hardware circuitry (e.g., logic circuitry).

[0052] Figure 2 Some of the processes performed by the steering control unit 1 are shown. Figure 2 The processes shown are some of the processes implemented when the CPU 49a executes a program stored in memory 49b, and these processes are described according to the type of processes to be implemented.

[0053] The steering control unit 1 has a steering-side control unit 50 and a steering-side control unit 60. The steering-side control unit 50 controls the power supply to the steering-side motor 13. The steering-side control unit 50 has a steering-side current sensor 55. The steering-side current sensor 55 detects the actual steering-side current value Ia, which is obtained from the current value of each phase of the steering-side motor 13, flowing through the connection line between the steering-side control unit 50 and the motor coils in each phase of the steering-side motor 13. The steering-side current sensor 55 takes the voltage drop of a shunt resistor as current, which is connected to the source side of each switching element in an inverter (not shown), configured to correspond to the steering-side motor 13. Figure 2 In this embodiment, for ease of description, the connecting lines in each phase and the current sensors in each phase are shown together as a single connecting line and a single current sensor. This is an example of a steering-side control unit 50 controlling the steering device 2 by controlling the operation of the steering-side motor 13.

[0054] The rotating-side control unit 60 controls the power supply to the rotating-side motor 32. The rotating-side control unit 60 has a rotating-side current sensor 65. The rotating-side current sensor 65 detects the value Ib of the actual rotating-side current, which is obtained from the current value of each phase of the rotating-side motor 32, flowing through the connection between the rotating-side control unit 60 and the motor coils in each phase of the rotating-side motor 32. The rotating-side current sensor 65 takes the voltage drop of a shunt resistor as the current, which is connected to the source side of each switching element in an inverter (not shown) configured to correspond to the rotating-side motor 32. Figure 2 In this embodiment, for ease of description, the connecting lines in each phase and the current sensors in each phase are shown together as a single connecting line and a single current sensor. This is an example of how the rotation-side control unit 60 controls the control unit of the steering device 2 by controlling the operation of the rotation-side motor 32.

[0055] Steering side control unit 50

[0056] like Figure 2As shown, steering torque Th, vehicle speed V, rotation angle θa, actual current value Ib on the steering side, pinion angle θp, start signal Sig, and battery replacement information FLG2 are input to the steering side control unit 50. Based on steering torque Th, vehicle speed V, rotation angle θa, actual current value Ib on the steering side, pinion angle θp, start signal Sig, and battery replacement information FLG2, the steering side control unit 50 controls the power supply to the steering side motor 13. The start signal Sig is a signal indicating the on or off state of the start switch 48. The battery replacement information FLG2 is information indicating whether the vehicle is in a state after the battery 47 belonging to the power system 46 has been removed and replaced. If the start switch 48 is switched to the on state after the battery 47 has been removed and replaced, the power system 46 sets the value "1" to the battery replacement information FLG2. The battery replacement information FLG2 with a value of "1" indicates the first power start since the battery replacement. When the start switch 48 is switched to the ON state and the battery 47 has not been removed or replaced, the power system 46 sets the value "0" to battery replacement information FLG2. Battery replacement information FLG2 with a value of "0" indicates that the power supply is not being started for the first time since the battery replacement. Therefore, the obtained battery replacement information FLG2 is output to the steering-side control unit 50 and the rotation-side control unit 60 via dedicated signal lines.

[0057] The steering-side control unit 50 includes a steering angle calculation unit 51, a target reaction force torque calculation unit 52, a steering-side correction information calculation unit 53, and a current application control unit 54. The rotation angle θa and the set steering angle θs0 are input to the steering angle calculation unit 51. Based on the set steering angle θs0, the steering angle calculation unit 51 converts the rotation angle θa into an integral angle according to the steering-side midpoint information θns stored in the storage unit 51a. The integral angle is a value converted over a range exceeding 360° by counting the revolutions of the steering-side motor 13 according to the steering-side midpoint information θns. The set steering angle θs0 is calculated by the steering-side correction information calculation unit 53. The steering-side midpoint information θns is, for example, information indicating the steering neutral position, which is the position of the steering wheel 3 when the vehicle is moving in a straight line. The storage unit 51a is a predetermined storage area of ​​the memory 49b. The steering angle calculation unit 51 calculates the steering angle θs by multiplying the integral angle obtained through conversion by a conversion factor based on the rotational speed ratio of the steering-side reduction mechanism 14. The steering angle calculation unit 51 calculates the steering angle θs as an absolute angle relative to the neutral steering position. The obtained steering angle θs is then output to the target reaction force torque calculation unit 52 and the rotation side control unit 60.

[0058] The steering torque Th, vehicle speed V, actual steering side current value Ib, steering angle θs, and pinion angle θp are input into the target reaction torque calculation unit 52. Based on the steering torque Th, vehicle speed V, actual steering side current value Ib, steering angle θs, and pinion angle θp, the target reaction torque calculation unit 52 calculates the target reaction torque TT*. The target reaction torque TT* is a control quantity used as the target of the steering reaction force of the steering wheel 3 that should be generated by the steering side motor 13. Therefore, the obtained target reaction torque TT* is output to the adder 56.

[0059] The rotation angle θa, the actual steering current value Ia, the steering midpoint information θns, the abnormal condition information FLG1, and the battery replacement information FLG2 are input into the steering correction information calculation unit 53. Based on the rotation angle θa, the actual steering current value Ia, the steering midpoint information θns, the abnormal condition information FLG1, and the battery replacement information FLG2, the steering correction information calculation unit 53 calculates the steering midpoint information θns, the abnormal condition information FLG1, and the set steering angle θs0. Therefore, the obtained steering midpoint information θns is written into the storage unit 51a. The abnormal condition information FLG1 is written into the storage unit 51b. The set steering angle θs0 is output to the steering angle calculation unit 51.

[0060] The steering side midpoint information θns is information set in the storage unit 51a by the steering side correction information calculation unit 53. The steering side correction information calculation unit 53 includes a steering side correction information storage process that acquires the steering side correction element information θcs and further writes the steering side midpoint information θns into the storage unit 51a. To acquire the steering side correction element information θcs, the rotation angle θa obtained from the steering unit 4 is used. The steering side midpoint information θns is obtained based on the acquired steering side correction element information θcs. The steering side correction information storage process includes a process for calculating the set steering angle θs0. The steering side correction information storage process will be described in detail later.

[0061] The abnormal condition information FLG1 is information set in storage unit 51b by the steering side correction information calculation unit 53. The steering side correction information storage process includes setting the abnormal condition information FLG1 in storage unit 51b. When the steering side correction information calculation unit 53 fails to complete writing the steering side center point information θns, it writes the abnormal condition information FLG1 with a value of "1" to storage unit 51b. In other words, the abnormal condition information FLG1 with a value of "1" indicates that the steering side center point information θns stored in storage unit 51a cannot be used normally. When the steering side correction information calculation unit 53 has successfully completed writing the steering side center point information θns, it writes the abnormal condition information FLG1 with a value of "0" to storage unit 51b. In other words, the abnormal condition information FLG1 with a value of "0" indicates that the steering side center point information θns stored in storage unit 51a can be used normally. In storage unit 51b, the abnormal condition information FLG1 with a value of "0" is stored as its initial value. For example, when the contents of storage unit 51b are cleared after a battery replacement, the exception condition information FLG1, with an initial value of "0", is stored therein. Storage unit 51b is a predetermined storage area of ​​memory 49b. Storage unit 51b is one of the storage areas of memory 49b that is different from storage unit 51a.

[0062] When the steering side correction element information θcs is obtained through the steering side correction information storage and processing, the steering side correction information calculation unit 53 calculates the target rotational torque RT* based on the rotation angle θa and the actual steering side current value Ia. The target rotational torque RT* is a control quantity used as the target for the rotational force of the steering wheel 3 that should be generated by the steering side motor 13. Therefore, the obtained target rotational torque RT* is output to the adder 56.

[0063] The target reaction torque TT* and the target rotational torque RT* are input into adder 56. Adder 56 calculates the steering-side motor torque command value Ts* by adding the target reaction torque TT* and the target rotational torque RT*. The target reaction torque TT* is calculated as a value other than "0" when the normal processing of rotating wheel 5 is performed based on the driver's steering operation, and when appropriate resistance is provided to the driver based on the road reaction force. The target rotational torque RT* is calculated as a value other than "0" when the steering-side correction information storage processing for acquiring steering-side correction element information θcs is performed, and when rotational torque is applied to rotate steering wheel 3. Therefore, under normal processing, the steering-side motor torque command value Ts* is the target reaction torque TT*. Under steering-side correction information storage processing, the steering-side motor torque command value Ts* is the target rotational torque RT*. The obtained steering-side motor torque command value Ts* is then output to current application control unit 54.

[0064] The steering-side motor torque command value Ts*, the rotation angle θa, and the actual steering-side current value Ia are input to the current application control unit 54. Based on the steering-side motor torque command value Ts*, the current application control unit 54 calculates the current command value Ia* for the steering-side motor 13. The current application control unit 54 obtains the difference between the current command value Ia* and the current value in the dq coordinate system obtained by converting the actual steering-side current value Ia based on the rotation angle θa, and controls the power supply to the steering-side motor 13 to eliminate this difference. Therefore, the steering-side motor 13 generates torque according to the steering-side motor torque command value Ts*.

[0065] Rotation side control unit 60

[0066] like Figure 2 As shown, vehicle speed V, rotation angle θb, pinion absolute rotation angle θabp, steering angle θs, start signal Sig, and battery replacement information FLG2 are input to the rotation-side control unit 60. Based on vehicle speed V, rotation angle θb, pinion absolute rotation angle θabp, steering angle θs, start signal Sig, and battery replacement information FLG2, the rotation-side control unit 60 controls the power supply to the rotation-side motor 32.

[0067] The rotating side control unit 60 includes a pinion angle calculation unit 61 and a pinion angle feedback control unit ( Figure 2 The components include the "pinion angle F / B control unit" 62, the rotation side correction information calculation unit 63, and the current application control unit 64.

[0068] The rotation angle θb and the set pinion angle θp0 are input into the pinion angle calculation unit 61. Based on the set pinion angle θp0, the pinion angle calculation unit 61 converts the rotation angle θb into an integral angle according to the rotation side midpoint information θnt stored in the storage unit 61a. By counting the revolutions of the rotation side motor 32 according to the rotation side midpoint information θnt, the integral angle is a value converted over a range of more than 360°. The set pinion angle θp0 is calculated by the rotation side correction information calculation unit 63. The rotation side midpoint information θnt is, for example, information indicating the rack neutral position, which is the position of the rack shaft 22 when the vehicle is moving in a straight line. The storage unit 61a is a predetermined storage area of ​​the memory 49b. The pinion angle calculation unit 61 calculates the pinion angle θp, which is the actual rotation angle of the pinion shaft 21, by multiplying the integral angle obtained by conversion by a conversion factor based on the speed ratio of the transmission mechanism 33, the lead of the conversion mechanism 34, and the speed ratio of the rack and pinion mechanism 24. Therefore, the pinion angle calculation unit 61 calculates the pinion angle θp as an absolute angle relative to the neutral position of the rack. The obtained pinion angle θp is then output to the pinion angle feedback control unit 62 and the steering side control unit 50.

[0069] Vehicle speed V, steering angle θs, and pinion angle θp are input to the pinion angle feedback control unit 62. The pinion angle feedback control unit 62 calculates the torque command value Tt* of the rotating side motor through feedback control of the pinion angle θp, so that the pinion angle θp adapts to the target pinion angle θp*. Considering the steering angle ratio, which is the ratio between the steering angle θs and the pinion angle θp, the target pinion angle θp* is calculated as an angle converted into a proportion relative to the steering angle θs. The pinion angle feedback control unit 62 changes the steering angle ratio according to the vehicle speed V. For example, the pinion angle feedback control unit 62 changes the steering angle ratio such that when the vehicle speed V is low, the pinion angle θp changes by a larger amount in response to the change in steering angle θs compared to when the vehicle speed V is high. Therefore, in the calculation of the target pinion angle θp*, a conversion calculation is performed so that the positional relationship with the steering angle θs satisfies a predetermined correspondence.

[0070] As the value of the rotation-side motor torque command value Tt*, during the normal processing of rotating the wheel 5 according to the driver's steering operation, a value other than "0" is calculated when the wheel 5 is rotated. As the value of the rotation-side motor torque command value Tt*, during the rotation-side correction information storage processing for obtaining the rotation-side correction element information θct (described later), the value is calculated as "0". Therefore, the obtained rotation-side motor torque command value Tt* is output to the current application control unit 64.

[0071] The rotation angle θb, the midpoint information θnt of the rotating side, the absolute rotation angle θabp of the pinion, the abnormal condition information FLG1, and the battery replacement information FLG2 are input into the rotating side correction information calculation unit 63. Based on the rotation angle θb, the midpoint information θnt of the rotating side, the absolute rotation angle θabp of the pinion, the abnormal condition information FLG1, and the battery replacement information FLG2, the rotating side correction information calculation unit 63 calculates the midpoint information θnt of the rotating side, the abnormal condition information FLG1, and the set pinion angle θp0. Therefore, the obtained midpoint information θnt of the rotating side is written into the storage unit 61a. The abnormal condition information FLG1 is written into the storage unit 61b. The set pinion angle θp0 is output to the pinion angle calculation unit 61.

[0072] The rotational midpoint information θnt is information set in the storage unit 61a by the rotational side correction information calculation unit 63. The rotational side correction information calculation unit 63 includes a rotational side correction information storage process that acquires the rotational side correction element information θct and further writes the rotational side midpoint information θnt into the storage unit 61a. To acquire the rotational side correction element information θct, the absolute rotation angle θabp of the pinion obtained from the rotation unit 6 is used. The rotational side midpoint information θnt is obtained based on the acquired rotational side correction element information θct. The rotational side correction information storage process includes a process for calculating the set pinion angle θp0. The rotational side correction information storage process will be described in detail later.

[0073] The abnormal condition information FLG1 is information set by the rotational side correction information calculation unit 63 in the storage unit 61b. The rotational side correction information storage process includes setting the abnormal condition information FLG1 in the storage unit 61b. When the rotational side correction information calculation unit 63 fails to complete writing the rotational side midpoint information θnt, it writes the abnormal condition information FLG1 with a value of "1" to the storage unit 61b. In other words, the abnormal condition information FLG1 with a value of "1" indicates that the rotational side midpoint information θnt stored in the storage unit 61a cannot be used normally. When the rotational side correction information calculation unit 63 has successfully completed writing the rotational side midpoint information θnt, it writes the abnormal condition information FLG1 with a value of "0" to the storage unit 61b. In other words, the abnormal condition information FLG1 with a value of "0" indicates that the rotational side midpoint information θnt stored in the storage unit 61a can be used normally. In the storage unit 61a, the abnormal condition information FLG1 with a value of "0" is stored as its initial value. For example, when the contents of storage unit 61a are cleared after a battery replacement, the exception condition information FLG1, with an initial value of "0", is stored therein. Storage unit 61b is a predetermined storage area of ​​memory 49b. Storage unit 61b is one of the storage areas of memory 49b that is different from storage unit 61a.

[0074] The rotation-side motor torque command value Tt*, the rotation angle θb, and the actual rotation-side current value Ib are input to the current application control unit 64. Based on the rotation-side motor torque command value Tt*, the current application control unit 64 calculates the current command value Ib* for the rotation-side motor 32. The current application control unit 64 obtains the difference between the current command value Ib* and the current value in the dq coordinate system obtained by converting the actual rotation-side current value Ib based on the rotation angle θb, and controls the power supply to the rotation-side motor 32 to eliminate this difference. Therefore, the rotation-side motor 32 rotates only by a certain angle according to the rotation-side motor torque command value Tt*.

[0075] Processing performed during startup

[0076] After the start switch 48 is turned on and the vehicle's power system 46 is activated based on a request from the driver via switch operation, the steering control unit 1 transitions from the starting state to the normal control state. Upon input of the start signal Sig, the steering-side control unit 50 transitions to the starting state to perform steering-side correction information storage processing. Similarly, upon input of the start signal Sig, the steering-side control unit 60 transitions to the starting state to perform steering-side correction information storage processing. In the starting state, the vehicle is stationary. Furthermore, in the starting state, the steering control unit 1 is in a state where it does not perform the normal processing of rotating the steering wheel 5 according to the driver's steering operation. Therefore, during the starting state period, the steering wheel 5 remains in the state it was in when the power was on.

[0077] Next, according to Figure 3 The flowchart shown illustrates an example of the processing procedure performed by the steering side control unit 50 through the steering side correction information calculation unit 53 in the starting state. Figure 3 As shown, after the input start signal Sig, the steering side correction information calculation unit 53 retrieves various information from the memory 49b (step 101). In step 101, the steering side correction information calculation unit 53 retrieves information including steering side center point information θns and abnormal condition information FLG1. For example, the steering side correction information calculation unit 53 retrieves the steering side center point information θns from the memory unit 51a and retrieves the abnormal condition information FLG1 from the memory unit 51b.

[0078] Next, the steering side correction information calculation unit 53 determines whether the abnormal condition is met (step 102). In step 102, the steering side correction information calculation unit 53 determines whether the writing of the steering side center point information θns has been successfully completed based on whether the abnormal condition information FLG1 retrieved in step 101 is "0". In this embodiment, the failure to complete the writing of the steering side center point information θns is an example of an abnormal condition. The processing in step 102 is an example of the abnormal condition determination process.

[0079] Next, when the steering side correction information calculation unit 53 retrieves the abnormal condition information FLG1 with the value "1" and determines in step 102 that the abnormal condition is met (step 102: yes), it performs steering side correction information storage processing (step 104). In step 104, the steering side correction information calculation unit 53 obtains the steering side correction element information θcs, and further writes the steering side midpoint information θns into the storage unit 51a through the steering side correction information storage processing. In this embodiment, the steering side correction element information θcs is an example of correction element information. The steering side midpoint information θns is an example of correction information.

[0080] On the other hand, when the steering side correction information calculation unit 53 retrieves the abnormal condition information FLG1 with a value of "0" and determines that the abnormal condition is not met (step 102: No), it determines whether the battery replacement condition is met (step 103). When no battery replacement information FLG2 is input in step 103, the steering side correction information calculation unit 53 determines that it is the first time the power has been started since the battery replacement. On the other hand, when no battery replacement information FLG2 is input, the steering side correction information calculation unit 53 determines that it is not the first time the power has been started since the battery replacement. In this embodiment, the first time the power has been started since the battery replacement is an example of the battery replacement condition. The processing in step 103 is an example of the battery replacement condition determination process.

[0081] In the contents of memory 49b, rewritable content is cleared and initialized in association with battery replacement. For example, the contents stored in memory cells 51a and 51b each correspond to rewritable content and are cleared and initialized in association with battery replacement. Therefore, by determining in step 103 that this is the first power-on since the battery replacement, the steering side correction information calculation unit 53 determines that the contents stored in memory cells 51a and 51b have been cleared and initialized. Conversely, by determining that this is not the first power-on since the battery replacement, the steering side correction information calculation unit 53 determines that the contents stored in memory cells 51a and 51b have not been cleared and initialized.

[0082] Next, when the steering side correction information calculation unit 53 determines that the battery replacement condition is met (step 103: yes), it performs steering side correction information storage processing (step 104). In step 104 under this case, if the determination result in step 102 is "yes", the steering side correction information calculation unit 53 obtains the steering side correction element information θcs, and also writes the steering side midpoint information θns into the storage unit 51a through the steering side correction information storage processing.

[0083] Next, the steering side correction information calculation unit 53 determines whether the steering side center point information θns has been written into the storage unit 51a through the steering side correction information storage processing performed in step 104 (step 105). In step 105, the steering side correction information calculation unit 53 uses, for example, a verification function. The verification function is a function that retrieves the steering side center point information θns that has been written into the storage unit 51a through the processing in step 104 and determines whether the retrieved steering side center point information θns matches the content written through the processing in step 104. Using the verification function, when the retrieved steering side center point information θns matches the content written through the processing in step 104, the steering side correction information calculation unit 53 determines that the writing of the steering side center point information θns into the storage unit 51a has been completed. On the other hand, using the verification function, when the retrieved steering side center point information θns does not match the content written through the processing in step 104, the steering side correction information calculation unit 53 determines that the writing of the steering side center point information θns into the storage unit 51a has not been completed.

[0084] Next, when the steering side correction information calculation unit 53 determines that the steering side midpoint information θns has been written into the storage unit 51a (step 105: yes), it writes the abnormal condition information FLG1 with the value "0" into the storage unit 51b (step 106).

[0085] Next, the steering side correction information calculation unit 53 calculates the set steering angle θs0 (step 107) and sets the completion of the process to be executed in the starting state. In step 107 in this case, the steering side correction information calculation unit 53 calculates the set steering angle θs0, which is obtained by correcting the rotation angle θa based on the steering side midpoint information θns written by the process in step 104. The set steering angle θs0 is an absolute angle relative to the steering neutral position and is used as the steering angle θs to be used when performing normal processing. After setting the completion of the process to be executed in the starting state, the steering side control unit 50 performs a state transition to the normal control state, in which the steering side control unit 50 performs normal processing to rotate the steering wheel 5 according to the driver's steering operation. In this embodiment, the rotation angle θa is an example of a state variable obtained from the steering unit 4. The steering angle θs, i.e., the set steering angle θs0, is an example of a steering control variable used when performing normal processing.

[0086] On the other hand, when the steering side correction information calculation unit 53 determines in step 105 that writing the steering side midpoint information θns into the storage unit 51a has failed (step 105: No), it writes the abnormal condition information FLG1 with the value "1" into the storage unit 51b (step 108). In this embodiment, the processing in step 108 is an example of abnormal information storage processing.

[0087] Next, the steering side correction information calculation unit 53 calculates the set steering angle θs0 (step 107) and sets the completion of the process to be executed in the starting state. In step 107 in this case, the steering side correction information calculation unit 53 calculates the set steering angle θs0, which is obtained by correcting the rotation angle θa based on the steering side midpoint information θns written by the process in step 104. Even if the writing is not completed by the process in step 104 (step 105: No), the value of the steering side midpoint information θns itself is determined to be a normal value. After setting the completion of the process to be executed in the starting state, the steering side control unit 50 performs a state transition to the normal control state. In the normal control state, the steering side control unit 50 performs normal processing to rotate the steering wheel 5 according to the driver's steering operation.

[0088] When the steering side correction information calculation unit 53 determines in step 103 that the battery replacement conditions are not met (step 103: No), it calculates the set steering angle θs0 (step 107) and completes the processing to be performed in the starting state. In step 107 in this case, the steering side correction information calculation unit 53 calculates the set steering angle θs0, which is obtained by correcting the rotation angle θa based on the steering side midpoint information θns retrieved by the processing in step 101. When the determination result of step 103 is No, the steering side correction information calculation unit 53 does not perform the steering side correction information storage processing (step 104).

[0089] In the start-up state, the rotation side control unit 60 executes the processing corresponding to that executed by the steering side correction information calculation unit 53 via the rotation side correction information calculation unit 63. For example, as a processing corresponding to step 101, after inputting the start signal Sig, the rotation side correction information calculation unit 63 retrieves various information from the memory 49b. In this case, the rotation side correction information calculation unit 63 retrieves the rotation side midpoint information θnt from the storage unit 61a and the abnormal condition information FLG1 from the storage unit 61b.

[0090] Next, as a process corresponding to step 102, the rotational side correction information calculation unit 63 determines whether the abnormal conditions are met. When the rotational side correction information calculation unit 63 retrieves the abnormal condition information FLG1 with the value "1" and determines that the abnormal conditions are met, it performs rotational side correction information storage processing as a process corresponding to step 104.

[0091] On the other hand, when the rotational side correction information calculation unit 63 retrieves the abnormal condition information FLG1 with a value of "0" and determines that the abnormal condition is not met, it determines whether the battery replacement condition is met, as a process corresponding to step 103. When the rotational side correction information calculation unit 63 determines that the battery replacement condition is met, it performs rotational side correction information storage processing, as a process corresponding to step 104.

[0092] Next, as a process corresponding to step 104, the rotational side correction information calculation unit 63 acquires the rotational side correction element information θct, and further writes the rotational side midpoint information θnt into the storage unit 61a through the rotational side correction information storage process. In this embodiment, the rotational side correction element information θct is an example of correction element information. The rotational side midpoint information θnt is an example of correction information.

[0093] Next, as a process corresponding to step 105, the rotational side correction information calculation unit 63 determines whether the rotational side midpoint information θnt has been written into the storage unit 61a through the rotational side correction information storage process. In this case, similar to the steering side correction information calculation unit 53, the rotational side correction information calculation unit 63 uses a verification function to determine whether the rotational side midpoint information θnt has been written into the storage unit 61a.

[0094] Next, when the rotational side correction information calculation unit 63 determines that the writing of the rotational side midpoint information θnt into the storage unit 61a has been completed, it writes the abnormal condition information FLG1 with a value of "0" into the storage unit 61b as processing corresponding to step 106. In this case, as processing corresponding to step 107, the rotational side correction information calculation unit 63 calculates the set pinion angle θp0 and sets the completion of the processing to be executed in the starting state. The rotational side correction information calculation unit 63 calculates the set pinion angle θp0, which is obtained by correcting the rotation angle θb based on the rotational side midpoint information θnt already written by the rotational side correction information storage processing. The set pinion angle θp0 is an absolute angle relative to the rack neutral position and is used as the pinion angle θp to be used when performing normal processing. After setting the completion of the processing to be executed in the starting state, the rotational side control unit 60 performs a state transition to the normal control state, in which the rotational side control unit 60 performs normal processing to rotate the rotation wheel 5 according to the driver's steering operation. In this embodiment, the rotation angle θb is an example of a state variable obtained from the rotation unit 6. The pinion angle θp, i.e., the set pinion angle θp0, is an example of a rotation control variable used during normal processing.

[0095] On the other hand, when the rotational side correction information calculation unit 63 determines that writing the rotational side midpoint information θnt into the storage unit 61a has failed, it writes the abnormal condition information FLG1 with a value of "1" into the storage unit 61b as a process corresponding to step 108. In this case, as a process corresponding to step 107, the rotational side correction information calculation unit 63 calculates the set pinion angle θp0 and sets the completion of the process to be executed in the starting state. The rotational side correction information calculation unit 63 calculates the set pinion angle θp0, which is obtained by correcting the rotation angle θb based on the rotational side midpoint information θnt already written by the rotational side correction information storage process. Even when the writing fails to be completed by the rotational side correction information storage process, the value of the rotational side midpoint information θnt itself is determined to be a normal value. After setting the completion of the process to be executed in the starting state, the rotational side control unit 60 performs a state transition to the normal control state, in which the rotational side control unit 60 performs normal processing to rotate the rotation wheel 5 according to the driver's steering operation.

[0096] When the rotational side correction information calculation unit 63 determines that the battery replacement conditions are not met, it calculates the set pinion angle θp0 and sets the completion of the process to be executed in the start-up state as the process corresponding to step 107. In this case, the rotational side correction information calculation unit 63 calculates the set pinion angle θp0, which is obtained by correcting the rotation angle θb based on the rotational side midpoint information θnt retrieved by the process corresponding to step 101. When the rotational side correction information calculation unit 63 determines that the battery replacement conditions are not met, it does not perform the rotational side correction information storage process.

[0097] Steering side correction information storage and processing

[0098] Next, according to Figure 4 The flowchart shown illustrates an example of the processing procedure of the steering side control unit 50 performing steering side correction information storage processing through the steering side correction information calculation unit 53.

[0099] like Figure 4As shown, the steering side correction information calculation unit 53 rotates the steering wheel 3 to the right, i.e., in one of the left and right directions (step 201). In step 201, the steering side correction information calculation unit 53 calculates the target rotational torque RT* for rotating the steering wheel 3 to the right. For example, the steering side correction information calculation unit 53 calculates the target rotational torque RT* by feedback control of the temporary steering angle θsi, such that the temporary steering angle θsi adapts to the target steering angle θs*. The temporary steering angle θsi is an integral angle obtained using the position of the rotation angle θa at power-on as a temporary reference value. The target steering angle θs* is updated so that the value of the temporary steering angle θsi at the start of the steering side correction information storage processing gradually changes to a value exceeding the right rotation limit position 3a within the rotation range of the steering wheel 3.

[0100] Next, the steering side correction information calculation unit 53 determines whether the steering wheel 3 has reached the right-turn limit position 3a (step 202). In step 202, for example, the steering side correction information calculation unit 53 monitors the actual steering side current value Ia. The actual steering side current value Ia does not undergo significant changes during the period until the steering wheel 3 reaches the right-turn limit position 3a. When the steering wheel 3 reaches the right-turn limit position 3a, the absolute value of the actual steering side current value Ia increases sharply. This is because the rotation of the steering shaft 11 is restricted by the limiter mechanism 11b, and the rotation of the steering side motor 13 is also restricted. In this case, as the steering side correction information calculation unit 53 attempts to further rotate the steering side motor 13 while the rotation of the steering side motor 13 is restricted, the target rotational torque RT* increases sharply, and the actual steering side current value Ia also increases sharply. When the absolute value of the actual steering side current value Ia is equal to or greater than the current threshold Iath, the steering side correction information calculation unit 53 determines that the steering wheel 3 has reached the right-turn limit position 3a. On the other hand, when the absolute value of the actual current value Ia on the steering side is less than the current threshold Iath, the steering side correction information calculation unit 53 determines that the steering wheel 3 has not yet reached the right rotation limit position 3a. For example, the current threshold Iath is set to a value within the range obtained experimentally, such that when the rotation of the steering shaft 11 is limited by the limiter mechanism 11b, the rotation of the steering side motor 13 is limited.

[0101] Next, when the steering side correction information calculation unit 53 determines that the steering wheel 3 has not reached the right turn limit position 3a (step 202: No), it repeats the processing of steps 201 and 202. On the other hand, when the steering side correction information calculation unit 53 determines that the steering wheel 3 has reached the right turn limit position 3a (step 202: Yes), it temporarily stores the temporary right limit position θrl (step 203). In step 203, the steering side correction information calculation unit 53 temporarily stores the temporary steering angle θsi at the time when it determines that the right turn limit position 3a has been reached as the temporary right limit position θrl. In this embodiment, the temporary right limit position θrl temporarily stored by the steering side correction information calculation unit 53 is an example of the steering side correction element information θcs.

[0102] Next, the steering side correction information calculation unit 53 rotates the steering wheel 3 to the left, that is, in a direction other than right (step 204). In step 204, the steering side correction information calculation unit 53 calculates the target rotational torque RT* for rotating the steering wheel 3 to the left. For example, as in the processing of step 201, the steering side correction information calculation unit 53 calculates the target rotational torque RT* by feedback control of the temporary steering angle θsi, so that the temporary steering angle θsi adapts to the target steering angle θs*. The target steering angle θs* is updated so that the value of the temporary steering angle θsi, which has reached the right rotation limit position 3a, gradually changes to a value exceeding the left rotation limit position 3b within the rotation range of the steering wheel 3.

[0103] Next, the steering side correction information calculation unit 53 determines whether the steering wheel 3 has reached the left rotation limit position 3b (step 205). In step 205, for example, as in the processing of step 205, the steering side correction information calculation unit 53 monitors the actual steering side current value Ia.

[0104] Next, when the steering side correction information calculation unit 53 determines that the steering wheel 3 has not reached the left rotation limit position 3b (step 205: No), it repeats the processing of steps 204 and 205. On the other hand, when the steering side correction information calculation unit 53 determines that the steering wheel 3 has reached the left rotation limit position 3b (step 205: Yes), it temporarily stores the temporary left limit position θll (step 206). In step 206, the steering side correction information calculation unit 53 temporarily stores the temporary steering angle θsi at the time when it determines that the left rotation limit position 3b has been reached as the temporary left limit position θll. In this embodiment, the temporary left limit position θll temporarily stored by the steering side correction information calculation unit 53 is an example of the steering side correction element information θcs.

[0105] Next, the steering side correction information calculation unit 53 calculates the actual measured steering range SR as the steering range of the steering wheel 3 (step 207). In step 207, the steering side correction information calculation unit 53 calculates the absolute value of the difference between the temporary right limit position θrl temporarily stored in step 203 and the temporary left limit position θll temporarily stored in step 206, as the actual measured steering range SR.

[0106] Next, the steering side correction information calculation unit 53 determines whether the actually measured steering range SR has been properly acquired (step 208). In step 208, the steering side correction information calculation unit 53 determines whether the absolute value of the difference between the actually measured steering range SR calculated in step 207 and the design value SR0 is less than the steering range threshold SRth. For example, if the driver obstructs the rotation of the steering wheel 3 by touching the steering wheel 3 during the processing of step 201 or step 204, the normal value may not be stored as a temporary right limit position θrl or a temporary left limit position θll. In this case, the actually measured steering range SR may not be properly acquired. When the absolute value of the difference between the actually measured steering range SR and the design value SR0 is equal to or greater than the steering range threshold SRth, the steering side correction information calculation unit 53 determines that the actually measured steering range SR has not been properly acquired. On the other hand, when the absolute value of the difference between the actually measured steering range SR and the design value SR0 is less than the steering range threshold SRth, the steering side correction information calculation unit 53 determines that the actually measured steering range SR has been properly acquired. For example, for each vehicle equipped with steering device 2, the design value SR0 is individually set to define the steering range of steering wheel 3. The steering range threshold SRth is set to a value within a range obtained taking tolerances into account (e.g., such that the actual measured steering range SR can be determined to be within a range that does not deviate from the design value SR0 of the steering range of steering wheel 3).

[0107] Next, when the steering side correction information calculation unit 53 determines that the actually measured steering range SR has failed to be acquired normally (step 208: No), it repeats the processing of steps 201 to 208. When the determination result of step 208 is No, since the steering side correction information storage processing has failed to end normally, the steering side correction information calculation unit 53 can set the processing to be executed in the starting state to be incomplete. In this case, for example, after setting the processing to be executed in the starting state to be incomplete, the steering side control unit 50 can perform a state transition to a fault state.

[0108] On the other hand, when the steering side correction information calculation unit 53 determines that the actual measured steering range SR has been successfully acquired (step 208: Yes), it calculates the actual measured neutral position (step 209). In step 209, the steering side correction information calculation unit 53 calculates the value corresponding to the midpoint between the temporary right limit position θrl temporarily stored in step 203 and the temporary left limit position θll temporarily stored in step 206, as the actual measured neutral position. The absolute value of the difference between the actual measured neutral position and the temporary right limit position θrl is equal to the absolute value of the difference between the actual measured neutral position and the temporary left limit position θll.

[0109] Next, the steering side correction information calculation unit 53 rotates the steering wheel 3 to the actually measured neutral position (step 210). In step 210, the steering side correction information calculation unit 53 calculates the target rotational torque RT* for rotating the steering wheel 3 to the actually measured neutral position calculated in step 209. For example, the steering side correction information calculation unit 53 calculates the target rotational torque RT* through feedback control of the temporary steering angle θsi, such that the temporary steering angle θsi adapts to the steering target angle θs*. The steering target angle θs* is an updated value so that the value of the temporary steering angle θsi, which has reached the leftward rotation limit position 3b within the rotation range of the steering wheel 3, gradually changes to a value indicating the actually measured neutral position.

[0110] Next, the steering side correction information calculation unit 53 determines whether the steering wheel 3 has reached the actually measured neutral position (step 211). In step 211, for example, the steering side correction information calculation unit 53 monitors the temporary steering angle θsi. When the temporary steering angle θsi matches the actually measured neutral position, the steering side correction information calculation unit 53 determines that the steering wheel 3 has reached the actually measured neutral position. On the other hand, when the temporary steering angle θsi does not match the actually measured neutral position, the steering side correction information calculation unit 53 determines that the steering wheel 3 has not reached the actually measured neutral position.

[0111] Next, when the steering side correction information calculation unit 53 determines that the steering wheel 3 has not reached the actually measured neutral position (step 211: No), it repeats the processing of steps 210 and 211. On the other hand, when the steering side correction information calculation unit 53 determines that the steering wheel 3 has reached the actually measured neutral position (step 211: Yes), it writes the actually measured neutral position into the storage unit 51a (step 212). In step 212, the steering side correction information calculation unit 53 writes the temporary steering angle θsi corresponding to the actually measured intermediate position calculated in step 209 as the steering side midpoint information θns into the storage unit 51a. Then, the steering side correction information calculation unit 53 ends the steering side correction information storage processing and returns to Figure 3 The processing is carried out to perform step 105 and subsequent processing steps.

[0112] Steering wheel movement

[0113] Figure 5A This shows that the initial position of steering wheel 3 is the neutral steering position when the steering side correction information storage processing is initiated. Figure 5A The case of "0" in the text.

[0114] For example, such as Figure 5A As shown, when the steering side correction information storage processing is initiated, the steering wheel 3 begins to rotate to the right. In this case, as... Figure 5G As shown, during the period up to time t1, the temporary steering angle θsi is updated as the target steering angle θs* changes from "0" toward the positive side as the rightward rotation limit position 3a is exceeded. Figure 5G The "θsi(+)" in the text gradually changes. Figure 5G In the diagram, the solid line shows the change in the temporary steering angle θsi, and the dashed lines of varying lengths show the change in the target steering angle θs*.

[0115] Next, as Figure 5B As shown, when the steering wheel 3 reaches the rightward rotation limit position 3a, the rotation stops. In this case, as... Figure 5G As shown, when time t1 is reached, the temporary steering angle θsi has a value corresponding to the right turn limit position 3a, and does not change thereafter. Even after the temporary steering angle θsi has stopped changing, the target steering angle θs* continues to change. Thereafter, as... Figure 5G As shown, when the absolute value of the actual current value Ia on the steering side becomes equal to or greater than the current threshold Iath at time t2, the first value θsi1, which is the value of the temporary steering angle θsi at that time, is temporarily stored as the temporary right limit position θrl, i.e., the steering side correction element information θcs.

[0116] Next, as Figure 5C As shown in the diagram, steering wheel 3 begins to turn to the left. In this case, as... Figure 5G As shown, during the period up to time t3, the temporary steering angle θsi is updated as the target steering angle θs* changes from "0" toward the negative side as the leftward rotation limit position 3b is exceeded. Figure 5G The "θsi(-)" in the text gradually changes.

[0117] Next, as Figure 5D As shown, rotation stops when the steering wheel 3 reaches the leftward rotation limit position 3b. In this case, as... Figure 5G As shown, when time t3 is reached, the temporary steering angle θsi has a value corresponding to the leftward rotation limit position 3b, and does not change thereafter. Even after the temporary steering angle θsi has stopped changing, the target steering angle θs* continues to change. Thereafter, as... Figure 5G As shown, when the absolute value of the actual current value Ia on the steering side becomes equal to or greater than the current threshold Iath at time t4, the second value θsi2, which is the value of the temporary steering angle θsi at that time, is temporarily stored as the temporary left limit position θll, i.e., the steering side correction element information θcs.

[0118] Next, as Figure 5E As shown, steering wheel 3 begins to rotate to the actual measured neutral position. Figure 5E (The "0" in the text). In this case, such as... Figure 5G As shown, during the period up to time t5, as the target turning angle θs* is updated to indicate the value of the neutral position actually measured, the temporary turning angle θsi gradually increases from the second value θsi2 toward “0”.

[0119] Next, as Figure 5F As shown, rotation stops when steering wheel 3 reaches the actually measured neutral position. In this case, as... Figure 5G As shown, when time t5 is reached, the temporary steering angle θsi presents a value corresponding to the actual measured neutral position and remains unchanged thereafter. Before the temporary steering angle θsi presents a value corresponding to the actual measured neutral position, the target steering angle θs* has stopped changing. Thereafter, the value corresponding to the actual measured neutral position is written as the steering side midpoint information θns into storage unit 51a, thus ending the steering side correction information storage process.

[0120] Rotational side correction information storage and processing

[0121] Next, according to Figure 6The flowchart shown illustrates an example of the processing procedure of the rotation side control unit 60 performing rotation side correction information storage processing via the rotation side correction information calculation unit 63. In this embodiment, the rotation side control unit 60 operates the rotation unit 6 without being associated with the execution of the rotation side correction information storage processing. Therefore, the rotating wheel 5 does not rotate during the execution of the rotation side correction information storage processing.

[0122] like Figure 6 As shown, the rotational correction information calculation unit 63 obtains the absolute rotation angle θabp of the pinion (step 301) and calculates the value corresponding to the neutral position of the rack (step 302). In step 302, the rotational correction information calculation unit 63 calculates the rotational correction element information θct, which is the number of revolutions corresponding to the absolute rotation angle θabp of the pinion. Furthermore, the rotational correction information calculation unit 63 calculates the value corresponding to the neutral position of the rack for the pinion angle θp, which is obtained by correcting the rotation angle θb based on the rotational correction element information θct.

[0123] Next, the rotational side correction information calculation unit 63 writes the value corresponding to the rack neutral position into the storage unit 61a (step 303). In step 303, the rotational side correction information calculation unit 63 writes the value corresponding to the rack neutral position calculated in step 302 as the rotational side midpoint information θnt into the storage unit 61a. Then, the rotational side correction information calculation unit 63 ends the rotational side correction information storage process and returns to the storage unit 61a. Figure 3 The processing is carried out to perform the processing corresponding to step 105 and subsequent processing.

[0124] The operation and advantages of the first embodiment

[0125] For example, even if the steering side correction information storage process has been performed after the battery replacement, if the steering side midpoint information θns is not written to the storage unit 51a during this process, the determination result of step 102 can be yes. In this case, when the power is turned on afterward, the steering side midpoint information θns stored in the storage unit 51a cannot be used. That is, the steering angle θs deviates from the actual state of the steering unit 4.

[0126] Therefore, when the steering side control unit 50 stores the abnormal condition information FLG1, which has a value of "1" determined by the steering side correction information calculation unit 53, in the storage unit 51b during startup (step 102: Yes), the steering side control unit 50 executes the steering side correction information storage process again (re-executes the steering side correction information storage process). Therefore, even if the steering side control unit 50 cannot use the steering side midpoint information θns stored in the storage unit 51a during the current power-on startup, it can use the correct steering side midpoint information θns by re-executing the steering side correction information storage process. By re-executing the steering side correction information storage process, the steering side control unit 50 can complete writing the steering side midpoint information θns into the storage unit 51b. In this case, the steering side control unit 50 can use the steering side midpoint information θns stored in the storage unit 51a during the next and subsequent power-on startups. Therefore, the steering side control unit 50 can create a situation where the rotation angle θa can be corrected based on the steering side midpoint information θns.

[0127] The above description also applies to the rotation-side control unit 60. Specifically, when the rotation-side control unit 60, in the startup state, stores the abnormal condition information FLG1, whose value is determined to be "1" by the rotation-side correction information calculation unit 63, in the storage unit 61b, the rotation-side control unit 60 performs the rotation-side correction information storage process again. Therefore, even if the rotation-side control unit 60 cannot use the rotation-side midpoint information θnt stored in the storage unit 61a during the current power-on startup, it can use the correct rotation-side midpoint information θnt by performing the rotation-side correction information storage process again. By performing the rotation-side correction information storage process again, the rotation-side control unit 60 can complete the writing of the rotation-side midpoint information θnt into the storage unit 61b. In this case, the rotation-side control unit 60 can use the rotation-side midpoint information θnt stored in the storage unit 61a during the next and subsequent power-on startups. Therefore, the rotation-side control unit 60 can create a situation where the rotation angle θb can be corrected based on the rotation-side midpoint information θnt.

[0128] Therefore, the control variables, including the steering angle θs and the pinion angle θp, are unlikely to deviate from the actual state of the steering device 2. The embodiments described above can also produce the operation and advantages described below.

[0129] (1-1) The steering-side control unit 50 is configured to store an abnormal condition information FLG1 with a value of "1" in storage unit 51b when writing the steering-side center point information θns to storage unit 51a fails during the starting state. Before the steering-side correction information storage process, a process is performed to determine whether the abnormal condition information FLG1 with a value of "1" is stored in storage unit 51b, i.e., whether the abnormal condition is met. Therefore, even if writing the steering-side center point information θns to storage unit 51a fails, the steering-side correction information storage process can be performed again when the vehicle's power is turned on next time. Therefore, the steering-side control unit 50 can correct the rotation angle θa based on the correct steering-side center point information θns. This also applies to the rotation-side control unit 60. Specifically, even if writing the rotation-side center point information θnt to storage unit 61a fails, the rotation-side correction information storage process can be performed again when the vehicle's power is turned on next time. Therefore, the rotation-side control unit 60 can correct the rotation angle θb based on the correct rotation-side center point information θnt.

[0130] (1-2) The steering-side control unit 50 is configured to determine whether battery replacement conditions are met in the starting state. Furthermore, the steering-side control unit 50 is configured to perform steering-side correction information storage processing when battery replacement conditions are met. The steering-side control unit 50 is configured to determine whether abnormal conditions are met before processing to determine whether battery replacement conditions are met. Therefore, even when battery replacement conditions are not met and therefore steering-side correction information storage processing is not required, steering-side correction information storage processing is performed when abnormal conditions are met. In the starting state, the steering-side control unit 50 can appropriately respond to abnormalities in storage unit 51a related to the steering-side center point information θns that has been written to storage unit 51a through steering-side correction information storage processing. Therefore, the reliability of the accuracy of the steering-side center point information θns can be improved. This also applies to the rotation-side control unit 60. Specifically, in the starting state, the rotation-side control unit 60 can appropriately respond to abnormalities in storage unit 61a related to the rotation-side center point information θnt that has been written to storage unit 61a through rotation-side correction information storage processing. Therefore, the reliability of the accuracy of the rotational midpoint information θnt can be improved.

[0131] (1-3) When an anomaly occurs related to the midpoint information θns and θnt, which are written as targets into the storage units 51a and 61a of the steering unit 4 and the rotation unit 6 respectively, the steering control device 1 can re-execute the correction information acquisition process for each unit. Therefore, the steering control device 1 can correct the rotation angles θa and θb related to the steering unit 4 and the rotation unit 6 respectively. Therefore, the steering angle θs and pinion angle θp used to control the steering unit 4 and the rotation unit 6 are unlikely to deviate from the actual state of these units.

[0132] (1-4) In the steering side correction information storage and processing, the steering side midpoint information θns corresponding to the actual state of the steering unit 4 can be written into the storage unit 51a. Therefore, the steering side midpoint information θns presents a value reflecting the actual state of the steering unit 4. This is effective for properly calculating the steering angle θs, which is an important parameter used to control the steering side motor 13.

[0133] (1-5) In the startup state, instead of acquiring the rotational midpoint information θnt stored in the storage unit 61a, the rotational control unit 60 can calculate the set pinion angle θp0 using the pinion absolute rotation angle θabp obtained from the pinion absolute angle sensor 45. However, when acquiring the rotational midpoint information θnt stored in the storage unit 61a, the time spent calculating the set pinion angle θp0 is shorter than when acquiring the pinion absolute rotation angle θabp from the pinion absolute angle sensor 45 via a dedicated signal line. This is effective in shortening the time spent on the state transition to normal control state after power-on.

[0134] Second Implementation Method

[0135] Next, a second embodiment of the present disclosure will be described. For ease of description, the same components as in the first embodiment will be indicated by the same reference numerals as in the first embodiment, and their description will be omitted.

[0136] Various sensors connected to the steering control device 1 according to this embodiment include a steering absolute angle sensor 70. (As shown by...) Figure 1As indicated by the long and short dashed lines, the steering absolute angle sensor 70 detects the steering absolute rotation angle θabs, which is the actual measured value of the angle of the rotation axis of the steering shaft 11 over a range exceeding 360°. Specifically, the steering absolute angle sensor 70 is disposed on the steering shaft 11. For example, the steering absolute angle sensor 70 is disposed on the steering shaft 11 between the steering wheel 3 and the torque sensor 41. The steering absolute rotation angle θabs of the steering shaft 11 is used to calculate the steering angle θs. For example, the steering absolute rotation angle θabs is detected as a positive value when the vehicle turns right and as a negative value when the vehicle turns left. In this embodiment, the steering absolute angle sensor 70 is an example of a sensor that detects the actual measured value of the steering angle θs.

[0137] Instead of the abnormal condition information FLG1, the absolute steering rotation angle θabs is input into the steering side correction information calculation unit 53 according to this embodiment.

[0138] Processing performed during startup

[0139] Next, according to Figure 7 The flowchart shown is an example of the processing procedure performed by the steering side control unit 50 through the steering side correction information calculation unit 53 in the starting state.

[0140] like Figure 7 As shown, after the input start signal Sig, the steering side correction information calculation unit 53 retrieves various information from the memory 49b (step 401). In step 401, the steering side correction information calculation unit 53 retrieves information including the steering side center point information θns. For example, the steering side correction information calculation unit 53 retrieves the steering side center point information θns from the storage unit 51a.

[0141] Next, the steering side correction information calculation unit 53 determines whether the battery replacement conditions are met (step 402). When the steering side correction information calculation unit 53 determines that the battery replacement conditions are met (step 402: yes), it performs steering side correction information storage processing (step 403) and calculates the set steering angle θs0 (step 404). On the other hand, when the steering side correction information calculation unit 53 determines that the battery replacement conditions are not met (step 402: no), it calculates the set steering angle θs0 (step 404). When the determination result of step 402 is no, the steering side correction information calculation unit 53 does not perform steering side correction information storage processing (step 403).

[0142] Next, the steering side correction information calculation unit 53 acquires the absolute steering rotation angle θabs (step 405) and determines whether an abnormal condition is met (step 406). In step 406, the steering side correction information calculation unit 53 determines whether an abnormal condition is met, for example, based on the result of comparing the set steering angle θs0 calculated by the processing in step 404 with the absolute steering rotation angle θabs acquired by the processing in step 405. The steering side correction information calculation unit 53 determines whether the absolute value of the difference between the set steering angle θs0 and the absolute steering rotation angle θabs is less than the steering side threshold θths. For example, if the steering side midpoint information θns is not a normal value, a difference occurs between the set steering angle θs0 and the absolute steering rotation angle θabs. In this case, the steering side midpoint information θns may not be acquired normally. When the absolute value of the difference between the set steering angle θs0 and the absolute steering rotation angle θabs is equal to or greater than the steering side threshold θths, the steering side correction information calculation unit 53 determines that the steering side midpoint information θns has not been acquired normally. When the absolute value of the difference between the set steering angle θs0 and the absolute steering rotation angle θabs is less than the steering side threshold θths, the steering side correction information calculation unit 53 determines that the steering side midpoint information θns has been successfully acquired. For example, the steering side threshold θths is set to a value within a range that takes tolerances into account (e.g., a range that allows it to be determined that there is no difference between the set steering angle θs0 and the absolute steering rotation angle θabs). In this embodiment, failure to successfully acquire the steering side midpoint information θns is an example of an abnormal condition. The processing in step 102 is an example of an abnormal condition determination process.

[0143] Next, when the steering side correction information calculation unit 53 determines that the abnormal condition is met (step 406: yes), it returns to the processing of step 403 and performs the steering side correction information storage processing (step 403) and subsequent processing again.

[0144] On the other hand, when the steering side correction information calculation unit 53 determines that the abnormal conditions are not met (step 406: No), it sets the completion of the process to be executed in the starting state. After setting the completion of the process to be executed in the starting state, the steering side control unit 50 performs a state transition to the normal control state. In the normal control state, the steering side control unit 50 performs normal processing to rotate the steering wheel 5 according to the driver's steering operation.

[0145] The rotation side control unit 60 performs the starting state processing via the rotation side correction information calculation unit 63, through a processing procedure corresponding to that of the steering side correction information calculation unit 53. For example, as a process corresponding to step 401, after inputting the start signal Sig, the rotation side correction information calculation unit 63 retrieves various information from the memory 49b. In this case, the rotation side correction information calculation unit 63 retrieves the rotation side midpoint information θnt from the storage unit 61a.

[0146] Next, as a process corresponding to step 402, the rotational side correction information calculation unit 63 determines whether the battery replacement conditions are met. When the rotational side correction information calculation unit 63 determines that the battery replacement conditions are met, it performs rotational side correction information storage processing as a process corresponding to step 403, and calculates the set pinion angle θp0 as a process corresponding to step 404. On the other hand, when the rotational side correction information calculation unit 63 determines that the battery replacement conditions are not met, it calculates the set pinion angle θp0 as a process corresponding to step 404. When the rotational side correction information calculation unit 63 determines that the battery replacement conditions are not met, it does not perform rotational side correction information storage processing.

[0147] Next, as a process corresponding to steps 405 and 406, the rotational side correction information calculation unit 63 acquires the absolute rotation angle θabp of the pinion and determines whether an abnormal condition is met. In this case, the rotational side correction information calculation unit 63 determines whether an abnormal condition is met based on, for example, a comparison between the set pinion angle θp0 calculated in the process corresponding to step 404 and the absolute rotation angle θabp acquired in the process corresponding to step 405. The rotational side correction information calculation unit 63 determines whether the absolute value of the difference between the set pinion angle θp0 and the absolute rotation angle θabp is less than the rotational side threshold θtht. For example, if the rotational side midpoint information θnt is not a normal value, a difference occurs between the set pinion angle θp0 and the absolute rotation angle θabp. In this case, the rotational side midpoint information θnt may not be acquired normally. When the absolute value of the difference between the set pinion angle θp0 and the absolute rotation angle θabp is equal to or greater than the rotational side threshold θtht, the rotational side correction information calculation unit 63 determines that the rotational side midpoint information θnt has not been acquired normally. When the absolute value of the difference between the set pinion angle θp0 and the absolute rotation angle θabp of the pinion is less than the rotational side threshold θtht, the rotational side correction information calculation unit 63 determines that the rotational side midpoint information θnt has been successfully acquired. For example, the rotational side threshold θtht is set to a value within a range obtained after taking tolerances into account (e.g., a range in which it can be determined that there is no difference between the set pinion angle θp0 and the absolute rotation angle θabp of the pinion).

[0148] Next, when the rotational side correction information calculation unit 63 determines that the abnormal conditions are met, it returns to the processing corresponding to step 403 and performs the rotational side correction information storage processing and subsequent processing again.

[0149] On the other hand, when the rotation side correction information calculation unit 63 determines that the abnormal conditions are not met, it sets the completion of the process to be executed in the starting state. After setting the completion of the process to be executed in the starting state, the rotation side control unit 60 performs a state transition to the normal control state. In the normal control state, the rotation side control unit 60 performs normal processing to rotate the rotation wheel 5 according to the driver's steering operation.

[0150] The second embodiment described above can produce the same operation and advantages as the first embodiment, and can produce the same advantages as (1-3) to (1-5) of the first embodiment. In addition, the second embodiment can also produce the operation and advantages described below.

[0151] (2-1) The steering device 2 includes a steering absolute angle sensor 70. The processing in step 406 includes determining whether an abnormal condition is met based on the result of comparing the set steering angle θs0 and the steering absolute rotation angle θabs. After the steering side correction information storage processing, the processing to determine whether an abnormal condition is met based on the result of comparing the set steering angle θs0 and the steering absolute rotation angle θabs is executed. Therefore, even if the steering side midpoint information θns obtained through the steering side correction information storage processing performed during the starting state period is not a normal value, the steering side correction information storage processing can be performed again during the same period of the starting state. Therefore, the steering side control unit 50 can correct the rotation angle θa based on the correct steering side midpoint information θns. This also applies to the rotation side control unit 60. Specifically, even if the rotation side midpoint information θnt is not a normal value, the rotation side correction information storage processing can be performed again during the same period of the starting state. Therefore, the rotation side control unit 60 can correct the rotation angle θb based on the correct rotation side midpoint information θnt.

[0152] Other implementation methods

[0153] Each of the embodiments described above can be modified as follows. The following other embodiments can be combined with each other without causing technical inconsistencies.

[0154] -In the first embodiment described above, the steering-side control unit 50 can perform a process to determine whether the power supply has been activated for the first time since the battery replacement, based on the contents of the memory 49b and internal setting information corresponding to the battery replacement information FLG2. In this case... Figure 3 Step 103 should involve retrieving the information corresponding to battery replacement information FLG2 and determining whether the battery replacement conditions are met. Instead of step 108, Figure 3 The processing should include, when the determination result of step 105 is negative, maintaining the information corresponding to the battery replacement information FLG2 to ensure that the battery replacement conditions are met. Therefore, the processing of step 102 can be derived from... Figure 3 This is omitted in the processing. On the other hand, in Figure 3 In the processing, step 103 corresponds to the abnormal condition determination process. Another embodiment described herein can also be applied to the rotation-side control unit 60.

[0155] -In the first embodiment described above, Figure 3In the processing, steps 405 and 406 corresponding to the second embodiment can be added after the processing in step 107. In this case, as in the second embodiment described above, the steering device 2 should be equipped with a steering absolute angle sensor 70. Other embodiments described herein can provide the operation and advantages described in the first and second embodiments.

[0156] The first embodiment described above should be applicable at least to, for example, the steering-side control unit 50. In this case, the second embodiment should be applicable to the rotation-side control unit 60. The rotation-side control unit 60 can be configured to calculate the set pinion angle θp0 whenever the power is turned on by acquiring the absolute rotation angle θabp of the pinion and calculating the value corresponding to the neutral position of the rack.

[0157] The second embodiment described above should at least apply to, for example, the rotation-side control unit 60. In this case, the first embodiment should apply to the steering-side control unit 50.

[0158] - In each of the embodiments described above, the steering-side control unit 50 and the rotation-side control unit 60 may perform a synchronization process to synchronize the steering wheel 3 and the rotating wheel 5 after setting the set steering angle θs0 and the set pinion angle θp0, so that the positional relationship between their positions satisfies a predetermined correspondence. In this case, the steering-side control unit 50 and the rotation-side control unit 60 should be configured to complete the process to be executed in the starting state after the synchronization process is completed.

[0159] - In each of the embodiments described above, the processing procedure for storing and processing steering side correction information is not limited to Figure 4 The process shown can be modified as appropriate. For example, the order of processing can be changed so that it is performed after steps 204 to 206. Figure 4 Steps 201 to 203 are shown.

[0160] - In each of the embodiments described above, the steering side correction information can be stored and processed, i.e. Figure 4 The processing steps 210 and 211 are omitted in the processing. The processing steps 210 and 211 can be the processing of rotating the steering wheel 3 to the temporary right limit position θrl or the temporary left limit position θll. That is to say, the processing steps 210 and 211 should be the processing to allow the position of the steering wheel 3 to reach the predefined position after the steering side correction information storage processing is performed.

[0161] - In each of the embodiments described above, it is not necessary for the target reaction torque calculation unit 52 to use steering torque Th, vehicle speed V, actual current value Ib on the rotating side, steering angle θs, and pinion angle θp as inputs to calculate the target reaction torque TT*. For example, steering torque Th and vehicle speed V can be used as inputs to calculate the target reaction torque TT*.

[0162] - In each of the embodiments described above, the processing performed by the pinion angle calculation unit 61 may be a process of converting the detected value of the movement of the rack shaft 22 into a pinion angle θp. In this case, with respect to the embodiments described above, the control quantity related to the pinion angle θp, etc., is converted by the detected value of the movement of the rack shaft 22. In another embodiment described here, the detected value of the movement of the rack shaft 22 corresponds to a state variable obtained from the rotation unit 6.

[0163] - In each of the embodiments described above, the operating member operated by the driver to steer the vehicle is not limited to the steering wheel 3. For example, the operating member may be a joystick.

[0164] - In each of the embodiments described above, the steering-side motor 13 mechanically coupled to the steering wheel 3 is not limited to a three-phase brushless motor. For example, the steering-side motor 13 may be a DC motor with brushes.

[0165] - Each of the embodiments described above does not necessarily include a steering-side deceleration mechanism 14.

[0166] In each of the embodiments described above, the rotation unit 6 transmits the rotation of the rotation-side motor 32 to the conversion mechanism 34 via the transmission mechanism 33. However, it is not limited to this; for example, the rotation unit 6 may be configured to transmit the rotation of the rotation-side motor 32 to the conversion mechanism 34 via a gear mechanism. Furthermore, the rotation unit 6 may be configured such that the rotation-side motor 32 directly rotates the conversion mechanism 34. Additionally, the rotation unit 6 may have a configuration including a second rack and pinion mechanism, and the rotation unit 6 may be configured to convert the rotation of the rotation-side motor 32 into the reciprocating motion of the rack shaft 22 via the second rack and pinion mechanism.

[0167] - In each of the embodiments described above, the rotating unit 6 is not limited to a configuration in which the right rotating wheel 5 and the left rotating wheel 5 rotate in conjunction with each other. In other words, the right rotating wheel 5 and the left rotating wheel 5 can be controlled independently.

[0168] - In the embodiment described above, the steering device 2 has a linkageless structure in which the steering unit 4 and the rotating unit 6 are always mechanically separated from each other. However, it is not limited to this, and the steering device 2 may have a structure in which the steering unit 4 and the rotating unit 6 can be mechanically separated from each other, for example, by a clutch.

Claims

1. A steering control system for controlling a vehicle steering device (2), the steering device (2) having a structure in which the power transmission path between a steering unit (4) having an operating member and a rotating unit (6) configured to rotate a rotating wheel is interrupted. The steering control system is characterized by including: A storage unit that stores information relating to the control of the steering device (2); as well as A control unit is configured to perform a state transition from a starting state to a normal control state after the vehicle's power system is started, wherein: The starting state is the state in which the control unit performs correction information storage processing. The correction information storage processing uses the state variables obtained from the steering device (2) to obtain correction element information, and further writes the correction information obtained based on the obtained correction element information into the storage unit. The normal control state is the state in which the control unit performs normal processing, which uses control variables obtained by correcting the state variables based on the correction information to control the steering device (2). The control unit is configured to perform an anomaly condition determination process in the startup state. This process determines whether an anomaly condition is met, wherein the anomaly condition indicates that the correction information already written to the storage unit through the correction information storage process is abnormal. The correction information storage process is a process that is re-executed when the abnormal condition is met, and The abnormal condition determination process is a process performed at least before or after the correction information storage process.

2. The steering control system according to claim 1, characterized in that: The control unit is configured to perform anomaly information storage processing in the startup state, wherein the anomaly information storage processing writes anomaly condition information into the storage unit when the writing of correction information into the storage unit cannot be completed; as well as The abnormal condition determination process is a process performed before the correction information storage process, and includes a process of determining that the abnormal condition is met when the abnormal condition information has been written into the storage unit.

3. The steering control system according to claim 2, characterized in that: The control unit is configured to perform a battery replacement condition determination process in the starting state, the battery replacement condition determination process determining whether a battery replacement condition is met, the battery replacement condition indicating the state after the battery of the power system of the vehicle has been removed and replaced; The correction information storage process is executed when the battery replacement conditions are met and not executed when the battery replacement conditions are not met. as well as The abnormal condition determination process is performed before the battery replacement condition determination process.

4. The steering control system according to claim 1, characterized in that: The steering device (2) includes a sensor that detects actual measured values ​​corresponding to the control variables obtained by correction based on the correction information; and The abnormal condition determination process is performed after the correction information storage process, and includes a process for determining whether the abnormal condition is met based on the result of a comparison, which is a comparison between the control variable obtained by correction based on the correction information and the actual measurement value obtained from the sensor.

5. The steering control system according to any one of claims 1 to 4, characterized in that: The correction information includes steering-side correction information and rotation-side correction information. The steering-side correction information is used to correct the information of the control variables used for steering when controlling the steering unit (4). The rotation-side correction information is used to correct the information of the control variables used for rotation when controlling the rotation unit (6). The correction information storage process includes steering side correction information storage process and rotation side correction information storage process. The steering side correction information storage process is to use the state variables obtained from the steering unit (4) to obtain steering side correction element information and further write the steering side correction information obtained based on the obtained steering side correction element information into the storage unit. The rotation side correction information storage process is to use the state variables obtained from the rotation unit (6) to obtain rotation side correction element information and further write the rotation side correction information obtained based on the obtained rotation side correction element information into the storage unit. as well as The abnormal condition determination process includes determining whether an abnormal condition indicating that the steering side correction information has been written into the storage unit through the steering side correction information storage process is met, and determining whether an abnormal condition indicating that the rotation side correction information has been written into the storage unit through the rotation side correction information storage process is met.

6. A steering control method for controlling a steering device (2) of a vehicle, the steering device (2) having a structure in which the power transmission path between a steering unit (4) having an operating member and a rotating unit (6) configured to rotate a rotating wheel (5) is interrupted. The steering control method is characterized by including: Store information related to the control of the steering device (2); as well as After the vehicle's power system is started, a state transition occurs from the starting state to the normal control state, wherein: The starting state is a state in which correction information storage processing is performed. The correction information storage processing uses the state variables obtained from the steering device (2) to obtain correction element information, and further stores the correction information obtained based on the obtained correction element information. The normal control state is a state in which normal processing is performed, which uses control variables obtained by correcting the state variables based on the correction information to control the steering device (2). The method includes performing an anomaly condition determination process in the startup state, the anomaly condition determination process determining whether an anomaly condition is met, the anomaly condition indicating that the correction information stored by the correction information storage process is abnormal. The correction information storage process is a process that is re-executed when the abnormal condition is met, and The abnormal condition determination process is a process performed at least before or after the correction information storage process.

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