Steering control system and steering control method

Abstract

To provide a steering control system capable of restraining mutual processing of a slave processing mode in respective control devices from becoming inconsistent.SOLUTION: The PU of each control device acquires a utilization state that defines the control device utilized for operating the actuators (S30). After acquiring the utilization state, the PU switches the processing mode to the automatic processing mode or the steering assist mode (S36, S38).SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a steering control system and a steering control method. [Background technology]

[0002] For example, Patent Document 1 listed below describes a steer-by-wire system in which power transmission between the steering shaft and the steered wheels is blocked. This system includes a reaction motor that applies a reaction force against the operation of the steering wheel, and a steering motor that steers the steered wheels. This system also has a redundant design with two control systems, each consisting of a control circuit for the reaction motor and a control circuit for the steering motor. This system is configured so that the control circuit used for control switches between specified operating modes depending on whether all control circuits are normal or whether an abnormality occurs in one of the control circuits. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2023-59527 Summary of the Invention [Problem to be solved by the invention]

[0004] However, after an abnormality occurs, the time it takes for each control circuit to detect the abnormality may vary, and this variation may result in discrepancies in the operating modes set by each control circuit. [Means for solving the problem]

[0005] The means for solving the above problems and their effects will be described below. 1. A steering control system comprising a reaction force actuator that applies a steering reaction force to the steering shaft when power transmission between the steering shaft and the steered wheels is cut off, and a steering actuator that steers the steered wheels, the steering control system comprising a reaction force control device whose operation target is the reaction force actuator, and a steering control device whose operation target is the steering actuator, wherein the processing modes of the reaction force control device and the steering control device each include one main processing mode and one or more slave processing modes, and each of the reaction force control device and the steering control device is configured to execute processing of the slave processing mode depending on the processing result of the main processing mode, and is configured to periodically repeat execution of processing of the main processing mode and execution of processing of the slave processing mode, and wherein the steering control system is configured to execute processing of the main processing mode prior to the periodic execution of processing of the slave processing mode.

[0006] In the above configuration, the process in the main processing mode is executed before the process in the slave processing mode. The process in the slave processing mode is executed according to the result of the process in the main processing mode. Therefore, by executing the process in the main processing mode before the process in the slave processing mode, it is possible to prevent inconsistencies between the processes in the slave processing modes of the respective control devices.

[0007] 2. A steering control system as described in 1 above, wherein the processing in the main processing mode includes selectively setting one of a plurality of utilization states depending on whether or not there is an abnormality in each of the control devices that constitute the steering control system, and the utilization state is a state identified by which control device contributes to the operation of the actuator.

[0008] In the above configuration, each time the control device that contributes to the operation of the actuator is updated, the processing defined by the slave processing mode is executed according to the update result, thereby enabling appropriate processing to be executed according to the utilization state as the processing in the slave processing mode.

[0009] 3. A steering control system as described in claim 2, wherein the slave processing mode includes a steering assist mode, and the processing in the steering assist mode includes processing of applying a reaction force against the rotation of the steering shaft by the driver using the reaction force actuator, and operating the steering actuator in response to the operation of the steering shaft by the driver.

[0010] In the above configuration, the process of steering the steered wheels in response to the operation of the steering shaft by the driver can be appropriately executed according to the utilization state. 4. A steering control system as described in 2 above, wherein the slave processing mode includes an automatic processing mode, and the processing in the automatic processing mode includes at least one of a process of steering the steered wheels independently of the operation of the steering shaft, a process of controlling the rotation of the steering shaft, and a process of fixing the steering shaft.

[0011] In the above configuration, the processing defined by the automatic processing mode can be executed appropriately according to the utilization state. 5. A steering control system described in any one of 2 to 4 above, in which one of the control devices in the steering control system is selectively set as a transition master, and the control devices other than the transition master are configured to follow the utilization state set by the transition master through processing defined by the main processing mode.

[0012] In the above configuration, the control devices other than the transition master follow the utilization state set by the transition master, which makes it possible to prevent discrepancies in the utilization states set by the control devices. 6. A steering control system according to claim 1, which is provided with a plurality of control systems each consisting of the reaction force control device and the steering control device, and is configured to operate the reaction force actuator and the steering actuator using the plurality of control systems.

[0013] In the above configuration, the steering control system has a larger number of control devices than when there is a single control system. Therefore, if there is a discrepancy in the timing at which each control device grasps the other's status, the consistency of processing in the slave processing mode is likely to deteriorate. Therefore, the utility value of executing the master processing mode before the slave processing mode is particularly great.

[0014] 7. A steering control method applied to a system including a reaction force actuator that applies a steering reaction force to the steering shaft when power transmission between the steering shaft and the steered wheels is cut off, a steering actuator that steers the steered wheels, a reaction force control device in which the reaction force actuator is the object of operation, and a steering control device in which the steering actuator is the object of operation, wherein the processing modes of the reaction force control device and the steering control device each include one main processing mode and one or more slave processing modes, the steering control method including: each of the reaction force control device and the steering control device executing processing in the slave processing mode in accordance with the processing result of the main processing mode, and periodically repeating the execution of processing in the main processing mode and the execution of processing in the slave processing mode; and each of the reaction force control device and the steering control device executing processing in the main processing mode prior to the periodic execution of processing in the slave processing mode.

[0015] In the above method, the process in the main processing mode is executed before the process in the slave processing mode. The process in the slave processing mode is executed depending on the result of the process in the main processing mode. Therefore, by executing the process in the main processing mode before the process in the slave processing mode, it is possible to prevent inconsistencies between the processes in the slave processing modes of the respective control devices. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a block diagram showing a configuration of a steering control system according to an embodiment. [Figure 2] 2 is a block diagram showing a process executed by the steering control system shown in FIG. 1. FIG. [Figure 3]FIG. 2 is a state transition diagram of the steering control system shown in FIG. [Figure 4] FIG. 2 is a state transition diagram of the steering control system shown in FIG. [Figure 5] FIG. 2 is a state transition diagram of the steering control system shown in FIG. [Figure 6] FIG. 2 is a state transition diagram of the steering control system shown in FIG. [Figure 7] FIG. 2 is a state transition diagram of the steering control system shown in FIG. [Figure 8] 2 is a flowchart showing the procedure of processing executed by each control device of the steering control system shown in FIG. [Figure 9] 2 is a flowchart showing the procedure of processing executed by each control device of the steering control system shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, an embodiment will be described with reference to the drawings. "Prerequisite configuration" FIG. 1 shows the configuration of a steering control system according to this embodiment. A steering wheel 10 is an operating unit through which a driver expresses his or her steering intention. A reaction force actuator Ar is configured to apply a reaction force that resists the driver's operation of the steering wheel 10. The reaction force actuator Ar includes a reaction force motor 12. The reaction force motor 12 includes a rotor 14, a stator coil 16(1) of a first control system, and a stator coil 16(2) of a second control system. As an example, the stator coils 16(1) and 16(2) have the same specifications. Furthermore, as an example, the stator coils 16(1) and 16(2) are symmetrical. Therefore, the magnetic flux of the magnet included in the rotor 14 equally interlinks both the stator coils 16(1) and 16(2). If the current flowing through stator coil 16(1) is equal to the current flowing through stator coil 16(2), the torque generated by energizing stator coil 16(1) is equal to the torque generated by energizing stator coil 16(2).

[0018] The numbers in parentheses for the stator coil 16(1) and the stator coil 16(2) are numbers for identifying the control systems. In the following, when referring to components of both the first control system and the second control system, the parentheses and the numbers in the parentheses will be omitted.

[0019] The configuration is such that the output voltage of inverter 18(i) is applied to stator coil 16(i) where "i=1, 2." Reaction force control device 20(i) includes PU 22 and storage device 24. Reaction force control device 20(i) is configured to control the control amount of the controlled object by having PU 22 execute a program stored in storage device 24.

[0020] The control target of the reaction force control device 20(i) is the steering wheel 10. The reaction force control device 20(i) operates the inverter 18(i) to control the reaction force applied to the steering wheel 10 as a control amount. To control the control amount, the reaction force control device 20(i) refers to the rotation angle θa(i) of the rotor 14 of the reaction force motor 12 detected by the rotation angle sensor 30(i). To control the control amount, the reaction force control device 20(i) also refers to the steering torque Th detected by the torque sensor 32. The steering torque Th is the torque applied to the steering wheel 10.

[0021] Power transmission between steerable wheels 40 and steering wheel 10 is cut off. Steerable wheels 40 are configured to be steered by steering actuator At. Steering actuator At includes steering motor 42. Steering motor 42 includes rotor 44, stator coil 46(1) of a first control system, and stator coil 46(2) of a second control system. Stator coil 46(1) and stator coil 46(2) are, for example, of the same specifications. Furthermore, stator coil 46(1) and stator coil 46(2) are, for example, symmetrical. Therefore, the magnetic flux of the magnet included in rotor 44 equally interlinks both stator coil 46(1) and stator coil 46(2). If the current flowing through stator coil 46(1) and the current flowing through stator coil 46(2) are equal, the torque generated by energizing stator coil 46(1) and the torque generated by energizing stator coil 46(2) are equal to each other.

[0022] The output voltage of inverter 48(i) is applied to stator coil 46(i). Steering control device 50(i) includes PU 52 and storage device 54. Steering control device 50(i) is configured to control the control amount of the controlled object by causing PU 52 to execute a program stored in storage device 54.

[0023] The control object of steering control device 50(i) is steered wheels 40. Steering control device 50(i) operates inverter 48(i) to control the steering angle of steered wheels 40 as a control variable. To control the control variable, steering control device 50(i) refers to rotation angle θb(i) of rotor 44 of steering motor 42 detected by rotation angle sensor 60(i). Steering control device 50(i) also refers to steering angle θs detected by steering sensor 62.

[0024] The reaction force control device 20(i) and the steering control device 50(i) of the i-th control system are capable of communicating with each other via an intra-system communication line Lc(i). Furthermore, the reaction force control device 20(1) of the first control system and the reaction force control device 20(2) of the second control system are capable of communicating with each other via a reaction force-side communication line Lms. Furthermore, the steering control device 50(1) of the first control system and the steering control device 50(2) of the second control system are capable of communicating with each other via a steering-side communication line Lmt.

[0025] "Steering control" Figure 2 shows some of the processes executed by the steering control system shown in Figure 1. Among the processes shown in Figure 2, the processes with the number (i) in parentheses are processes executed in the i-th control system.

[0026] "Processing Executed by the Reaction Force Control Device" Steering angle calculation process M10(i) is a process for calculating steering angle θh(i) based on rotation angle θa(i) as an input variable. Note that the steering angle θh calculated from the rotation angle θa(i) and the steering angle θs detected by steering sensor 62 are the same physical quantity. Target steering equivalent angle setting process M12(i) is a process for setting target steering equivalent angle θp*(i) based on steering angle θh(i) as an input variable. Target steering equivalent angle θp* is a target value of steering equivalent angle θp. Steering equivalent angle θp is a variable that indicates the steering angle of steered wheels 40. Target steering equivalent angle setting process M12(i) is a process for changing target steering equivalent angle θp*(i) in accordance with steering angle θh under the following conditions, for example: The condition is that the absolute value of the target equivalent steering angle θp* when the absolute value of the steering angle θh is large is equal to or greater than the absolute value of the target equivalent steering angle θp* when the absolute value of the steering angle θh is small.

[0027] In the description "changing B according to A while satisfying the condition that when A is large, B is equal to or greater than B when A is small," the case where A is large and the case where A is small refer to the relative relationship of magnitude when comparing the two. For example, "when A is large" corresponds to the case where "A is a first value," and "when A is small" corresponds to the case where "A is a second value smaller than the first value." Furthermore, the above description means that, depending on the settings of the first and second values, B when A is the first value may be larger than B when A is the second value. Furthermore, the above description means that B is changed according to A so that when B is large, A is larger than A when B is small.

[0028] The target steering torque setting process M14(i) is a process for setting a target steering torque Th*, which is a target value of the steering torque Th. The steering operation amount calculation process M16(i) is a process for calculating a target reaction torque Ts*(i) according to the operation amount of feedback control, in which the steering torque Th is the control amount. The selector M18(i) is a process for selectively outputting either the target reaction torque Ts*(1) or the target reaction torque Ts*(2).

[0029] The reaction force operation process M20(i) is a process for generating an operation signal MSs(i) for the inverter 18(i) so that the torque generated by the reaction force motor 12 by energizing the stator coil 16(i) approaches "1 / 2" of the target reaction force torque Ts*. As a result, the reaction force control device 20(1) operates the inverter 18(1) and the reaction force control device 20(2) operates the inverter 18(2), so that the torque of the reaction force motor 12 is controlled to be equivalent to the target reaction force torque Ts*.

[0030] "Processing Executed by the Steering Control Device" The steering equivalent angle calculation process M30(i) is a process for calculating a steering equivalent angle θp(i) based on the rotation angle θb(i) as an input variable.

[0031] The failure target value setting process M32(i) is a process that sets a target steering equivalent angle θp*(i) based on the steering angle θs as an input variable. The failure target value setting process M32(i) is a process that changes the target steering equivalent angle θp* in accordance with the steering angle θs, for example, under the following condition: The condition is that the absolute value of the target steering equivalent angle θp* when the absolute value of the steering angle θs is large is equal to or greater than the absolute value of the target steering equivalent angle θp* when the absolute value of the steering angle θs is small. Note that even if the values ​​of the input variables are equal to each other, the target steering equivalent angle θp* output by the failure target value setting process M32(i) does not have to be equal to the target steering equivalent angle θp* set by the target steering equivalent angle setting process M12(i).

[0032] The selector M34(i) is a process that selectively outputs either the target steering equivalent angle θp*(i) set by the target steering equivalent angle setting process M12(i) or the target steering equivalent angle θp*(i) set by the fail target value setting process M32(i). The value of the output variable of the selector M34(i) is, in principle, the target steering equivalent angle θp*(i) set by the target steering equivalent angle setting process M12(i).

[0033] Steering operation amount calculation process M36(i) is a process for calculating target steering torque Tt*(i) in accordance with the operation amount of feedback control in which the steering equivalent angle θp(i) is the control amount. Selector M38(i) is a process for selectively outputting either target steering torque Tt*(1) output by steering operation amount calculation process M36(1) or target steering torque Tt*(2) output by steering operation amount calculation process M36(2).

[0034] Steering operation process M40(i) is a process for generating operation signal MSt(i) for inverter 48(i) so that the torque generated in steering motor 42 by energizing stator coil 46(i) approaches "1 / 2" of target steering torque Tt*. As a result, steering control device 50(1) operates inverter 48(1) and steering control device 50(2) operates inverter 48(2), so that the torque of steering motor 42 is controlled to be equivalent to target steering torque Tt*.

[0035] "Main control system, sub-control system" In this embodiment, the first control system is generally set as the main control system. The main control system operates the actuator in accordance with a command value set by the main control system. On the other hand, the sub-control system operates the actuator in accordance with a command value set by the main control system. That is, when the first control system is the main control system, selector M18(i) outputs target reaction torque Ts*(1). Furthermore, reaction force control device 20(i) controls the torque generated by reaction motor 12 to approach "1 / 2" of target reaction torque Ts*(1) by energizing stator coil 16(i). Furthermore, when the first control system is the main control system, selector M38(i) outputs target turning torque Tt*(1). Furthermore, steering control device 50(i) controls the torque generated by turning motor 42 to approach "1 / 2" of target turning torque Tt*(1).

[0036] "Handling Abnormalities" The following describes the processing to be performed when an abnormality occurs in the steering control system. When an abnormality occurs, the operation of the actuator by the control device related to the abnormality is stopped. In other words, the control device used to operate the actuator is changed. Figures 3 to 7 show the transition of the utilization state of each control device depending on the abnormality. In Figures 3 to 7, the control system surrounded by a two-dot chain line is the main control system.

[0037] State 1 State 1 shown in Figure 3 is a state where no abnormality occurs. In state 1, reaction force control device 20(1) and steering control device 50(1) are surrounded by a two-dot chain line. That is, in state 1, the first control system is the main control system. Therefore, reaction force control device 20(2) operates inverter 18(2) in accordance with target reaction force torque Ts*(1) calculated by reaction force control device 20(1). Also, steering control device 50(2) operates inverter 48(2) in accordance with target turning torque Tt*(1) calculated by steering control device 50(1).

[0038] State 2 State 2 shown in FIG. 3 is a state in which the operation of steering actuator At by steering control device 50(2) of the second control system is stopped. State 2 is a state to which state 1 transitions when an abnormality occurs in the control by steering control device 50(2) of the second control system. Here, an abnormality in the control by reaction force control device 20 or steering control device 50 includes an abnormality in the control object, such as an inverter, as well as an abnormality in the control device itself. In other words, the control device executes self-diagnosis processing, etc. Therefore, if the self-diagnosis result indicates an abnormality, it means that an abnormality has occurred in the control by the control device. Furthermore, the control device executes abnormality diagnosis processing of the control object, such as a broken wire in the inverter. Then, if an abnormality occurs in the control object, it determines that there is an abnormality in the control by the control device. Note that abnormalities in the control device also include abnormalities that the control device cannot recognize. For example, if an abnormality occurs in the power supply to steering control device 50(2), the steering control device 50(2) itself may not be able to detect the abnormality. However, even in this case, the active state is set to the second state in which the operation of the steering actuator At by the steering control device 50(2) is stopped.

[0039] In the second state, the first control system is the main control system. Therefore, reaction force control device 20(2) operates inverter 18(2) in accordance with target reaction force torque Ts*(1) calculated by reaction force control device 20(1). However, the operation of steering actuator At is performed solely by steering control device 50(1) of the first control system.

[0040] State 3 State 3 shown in Fig. 3 is a state in which the operation of the reaction force actuator Ar by the reaction force control device 20(2) of the second control system is stopped. State 3 is a state to which the system transitions when an abnormality occurs in the control by the reaction force control device 20(2) of the second control system or a communication abnormality occurs in the second control system in State 1. The communication abnormality may be, for example, a break in the intra-system communication line Lc(2) or a short circuit in the intra-system communication line Lc(2).

[0041] In the third state, the first control system is the main control system. Therefore, steering control device 50(2) operates inverter 48(2) in accordance with target steering torque Tt*(1) calculated by steering control device 50(2). However, operation of reaction force actuator Ar is performed solely by reaction force control device 20(1) of the first control system.

[0042] State 4 3 is a state in which the operation of the reaction force actuator Ar by the reaction force control device 20(1) of the first control system is stopped. The fourth state is a state to which the vehicle transitions when an abnormality occurs in the control by the reaction force control device 20(1) of the first control system or a communication abnormality occurs in the first control system in the first state.

[0043] In the fourth state, the second control system is the main control system. Therefore, steering control device 50(1) operates inverter 48(1) in accordance with target steering torque Tt*(2) calculated by steering control device 50(2). However, operation of reaction force actuator Ar is performed solely by reaction force control device 20(2) of the second control system.

[0044] State 5 State 5 shown in Fig. 3 is a state in which the operation of steering actuator At by steering control device 50(1) of the first control system is stopped. State 5 is a state to which the system transitions when an abnormality occurs in the control by steering control device 50(1) of the first control system in State 1.

[0045] In the fifth state, the second control system is the main control system. Therefore, reaction force control device 20(1) operates inverter 18(1) in accordance with target reaction force torque Ts*(2) calculated by reaction force control device 20(2). However, the operation of steering actuator At is performed solely by steering control device 50(2) of the second control system.

[0046] State 6 State 6 shown in Fig. 4 is a state in which the operation of the actuator by the second control system is stopped. State 6 can be a state to which a transition occurs when a further abnormality occurs in State 2 or State 3. That is, State 6 is a state to which a transition occurs when an abnormality occurs in the control by reaction force control device 20(2) in State 2. State 6 is also a state to which a transition occurs when an abnormality occurs in the control by steering control device 50(2) in State 3.

[0047] In the sixth state, the first control system is the main control system. However, the operation of reaction force actuator Ar is performed solely by reaction force control device 20(1) of the first control system. Also, the operation of steering actuator At is performed solely by steering control device 50(1) of the first control system.

[0048] State 7 State 7 shown in Fig. 5 is a state in which the operation of the actuator by the first control system is stopped. State 7 can be a state to which a transition occurs when a further abnormality occurs in State 4 or State 5. That is, State 7 is a state to which a transition occurs when an abnormality occurs in the control by steering control device 50(1) in State 4. State 7 is also a state to which a transition occurs when an abnormality occurs in the control by reaction force control device 20(1) in State 5.

[0049] In the seventh state, the second control system is the main control system. However, the operation of reaction force actuator Ar is performed solely by reaction force control device 20(2) of the second control system. Also, the operation of steering actuator At is performed solely by steering control device 50(2) of the second control system.

[0050] State 8 State 8 shown in FIG. 6 is a state in which the operation of reaction force actuator Ar and the operation of steering actuator At by steering control device 50(2) are stopped. State 8 can be a state to which a transition occurs when a further abnormality occurs in State 2 or State 4. That is, State 8 is a state to which a transition occurs when an abnormality occurs in the control by reaction force control device 20(1) or the communication of the first control system in State 2. State 8 is also a state to which a transition occurs when an abnormality occurs in at least one of the three, namely, the control by reaction force control device 20(2), the communication of the second control system, and the control by steering control device 50(2), in State 4.

[0051] In state 8, the first control system is the main control system. However, in state 8, operation of reaction force actuator Ar is stopped. Meanwhile, operation of steering actuator At is carried out solely by steering control device 50(1) of the first control system. At this time, steering control device 50(1) calculates target steering torque Tt*(1) in accordance with target steering equivalent angle θp* set by fail-time target value setting process M32(1).

[0052] State 9 State 9 shown in FIG. 7 is a state in which the operation of reaction force actuator Ar and the operation of steering actuator At by steering control device 50(1) are stopped. State 9 can be a state to which a transition occurs when a further abnormality occurs in State 3 or State 5. That is, State 9 is a state to which a transition occurs when an abnormality occurs in at least one of the three, namely, the control by reaction force control device 20(1), the communication of the first control system, and the control by steering control device 50(1), in State 3. State 9 is also a state to which a transition occurs when an abnormality occurs in at least one of the two, namely, the control by reaction force control device 20(2) and the communication of the second control system, in State 5.

[0053] In the ninth state, the second control system is the main control system. However, in state 9, operation of reaction force actuator Ar is stopped. Meanwhile, operation of steering actuator At is carried out solely by steering control device 50(2) of the second control system. At this time, steering control device 50(2) calculates target steering torque Tt*(2) in accordance with target steering equivalent angle θp* set by fail-time target value setting process M32(2).

[0054] "Determining utilization status" In this embodiment, each control device constituting the steering control system can grasp, through communication, whether or not there is an abnormality in the other control devices, and execute processing to determine which utilization state to transition to. In other words, reaction force control devices 20(1), 20(2) and turning control devices 50(1), 50(2) can grasp, through communication, whether or not there is an abnormality in the other control devices, and execute processing to determine which utilization state to transition to. However, the steering control system is configured so that the other control devices follow the utilization state determined by the control device that is the transition master.

[0055] In this embodiment, in principle, reaction force control device 20 of the main control system is set as the transition master. However, for states 8 and 9, steering control device 50 that operates steering actuator At is set as the transition master. Each control device is configured to determine whether or not it is the transition master in accordance with this rule.

[0056] "Utilization state transition processing" Figure 8 shows the procedure for the transition process of the utilization state. The series of processes shown in Figure 8 is realized by the PU 22 repeatedly executing a program stored in the storage device 24 at a predetermined cycle. The series of processes shown in Figure 8 is also realized by the PU 54 repeatedly executing a program stored in the storage device 54 at a predetermined cycle. In Figure 8, the step number of each process is represented by a number preceded by an S. Hereinafter, the subject of the process will be referred to as PU 22, 52.

[0057] In the series of processes shown in Fig. 8, PUs 22, 54 acquire the results of diagnosis of the presence or absence of an abnormality by other control devices in the system via intra-system communication line Lc(i) (S10). That is, for example, PU 22 of reaction force control device 20(i) acquires the results of diagnosis of the presence or absence of an abnormality in turning control device 50(i). Also, for example, PU 52 of turning control device 50(i) acquires the results of diagnosis of the presence or absence of an abnormality in reaction force control device 20(i). The process of S10 includes a process of acquiring the results of diagnosis of the presence or absence of an abnormality in communication by each control device via intra-system communication line Lc(i). That is, the process of S10 includes, for example, a process by PU 22 of reaction force control device 20(i) to acquire the results of diagnosis of the presence or absence of an abnormality in its own intra-system communication line Lc(i).

[0058] Furthermore, the PUs 22 and 52 acquire the diagnosis results of the presence or absence of abnormalities in the other control systems via the reaction force side communication line Lms or the turning side communication line Lmt (S12). That is, for example, the reaction force control device 20(1) acquires the self-diagnosis results of the reaction force control device 20(2) and the self-diagnosis results of the turning control device 50(2) acquired by the reaction force control device 20(2) through the processing of S10.

[0059] Next, the PU 22, 54 determines whether or not there is an abnormality in the steering control system based on the results obtained by the processing of S10 and S12 (S14). Then, the PU 22, 52 determines whether or not it is the transition master based on the result of the processing of S14 (S16). If it determines that it is the transition master (S16: YES), the PU 22, 52 sets the utilization state to the determined state by determining which of states 1 to 9 the utilization state should be (S18). More specifically, the PU 22, 52 updates the data indicating the utilization state stored in a predetermined storage area of ​​the storage device 24, 54. Then, the PU 22, 52 notifies the other control devices of the utilization state set in the processing of S18 (S20).

[0060] On the other hand, if the PU 22, 52 determines that it is not the transition master (S16: NO), it receives the utilization state notified by the transition master executing the process of S20 (S22). Then, the PU 22, 52 sets the utilization state to the state received by the process of S22 (S24). Specifically, the PU 22, 52 updates the data indicating the utilization state stored in a predetermined storage area of ​​the storage device 24, 54.

[0061] When the processes of S20 and S24 are completed, the PUs 22 and 52 temporarily end the series of processes shown in FIG. About Processing Modes The process shown in Fig. 8 for setting the utilization state to one of the states is a utilization state setting process mode, which is one of the process modes executed by reaction force control device 20 and steering control device 50. The process modes executed by reaction force control device 20 and steering control device 50 also include a steering assist mode and an automatic process mode.

[0062] The steering assist mode is a mode in which a process for steering the steered wheels 40 is executed in response to the operation of the steering wheel 10. The automatic processing mode is a mode executed independently of the operation of the steering wheel 10. The automatic processing mode includes a process for aligning the steering angle θh with the steering equivalent angle θp when the vehicle start switch is switched from an OFF state to an ON state. Here, the steering angle θh and the steering equivalent angle θp being aligned means that the absolute value of the difference between the target steering equivalent angle θp* set in response to the steering angle θh and the steering equivalent angle θp is equal to or less than a predetermined value. The start switch is a switch that enables the vehicle to travel. For example, if the vehicle thrust generating device is a rotating electric motor, the start switch may be a switch that switches on a relay that cuts off the power supply to the rotating electric motor. The automatic processing mode also includes a process for realizing automatic steering of the vehicle by steering the steered wheels 40 independently of the operation of the steering wheel 10 when an automatic driving request for the vehicle is received. The automatic processing mode also includes a process for fixing the steering wheel 10 under predetermined conditions.

[0063] Fig. 9 shows the procedure for processing related to switching of processing modes according to this embodiment. The series of processes shown in Fig. 9 is realized by the PU 22 executing a program stored in the storage device 24 each time a predetermined condition is met. The series of processes shown in Fig. 9 is also realized by the PU 52 executing a program stored in the storage device 54 each time a predetermined condition is met. The predetermined condition is a condition indicating that the processing of S20 or S24 has been executed.

[0064] In the series of processes shown in Fig. 9, PU 22, 52 first acquires the utilization state indicated by the data updated by the process of S20 or S24 in a predetermined storage area of ​​storage device 24, 54 (S30). Then, PU 22, 52 determines whether pre-processing has been completed since the start switch was switched from the OFF state to the ON state (S32). The pre-processing includes an initial check of reaction force control device 20 or steering control device 50. The pre-processing also includes a process of matching steering angle θh and steering equivalent angle θp.

[0065] When it is determined that the pre-processing is completed (S32: NO), the PU 22, 52 determines whether or not there is an automatic driving request (S34). This process may be a process of determining whether or not an automatic driving request has been input to the steering control system from a host control device that is external to the steering control system and installed in the vehicle, for example.

[0066] When the PU 22, 52 determines that an automatic driving request is made (S34: YES) or that the pre-processing is incomplete (S32: YES), the PU 22, 52 sets the processing mode to the automatic processing mode (S36). On the other hand, when the PU 22, 52 determines that an automatic driving request is not made (S34: NO), the PU 22, 52 sets the processing mode to the assist steering mode (S38).

[0067] When the PUs 22 and 52 complete the processes of S36 and S38, they temporarily end the series of processes shown in FIG. "Actions and Effects of the Present Embodiment" Each of the four control devices, reaction force control devices 20(1), 20(2) and steering control devices 50(1), 50(2), communicates with one another and detects abnormalities. PUs 22, 52 repeatedly set the processing mode to an utilization state processing mode at a predetermined cycle, which determines the utilization state depending on whether or not there is an abnormality in each control device. After executing processing in the utilization state processing mode, PUs 22, 52 set the processing mode to the steering assist mode or the automatic processing mode. This allows processing in the steering assist mode or the automatic processing mode to be executed so as to be consistent with the latest utilization state.

[0068] According to the present embodiment described above, the following actions and effects can be further obtained. (1) The PUs 22 and 52 are set to the utilization state setting processing mode before setting the processing mode to the steering assist mode. This allows the PUs 22 and 52 to appropriately execute processing such as steering the steered wheels 40 in response to the driver's operation of the steering wheel 10 according to the utilization state.

[0069] (2) The PUs 22 and 52 are set to the active state setting processing mode before setting the processing mode to the automatic processing mode, so that the processing defined by the automatic processing mode can be executed appropriately according to the active state.

[0070] (3) The control devices other than the transition master are configured to follow the utilization state set by the transition master in the utilization state setting processing mode, thereby preventing discrepancies in the utilization states set by the control devices.

[0071] (4) The steering control system is provided with multiple control systems, each consisting of a reaction force control device 20 and a steering control device 50. Therefore, the steering control system has a larger number of control devices than when there is a single control system. Therefore, if there is a discrepancy in the timing at which each control device grasps the other's status, the consistency of the processing in the steering assist mode and the automatic processing mode is likely to decrease. Therefore, there is particularly great value in executing the utilization state setting processing mode prior to the steering assist mode or the automatic processing mode.

[0072] <Correspondence> The correspondence between the matters in the above embodiment and the matters described in the "Means for solving the problem" column is as follows. Below, the correspondence is shown for each number of the means for solving the problem described in the "Means for solving the problem" column. [1-4, 7] The main processing mode corresponds to the utilization state setting processing mode. The sub-processing mode corresponds to the steering assist mode and the automatic processing mode. [5] Corresponds to the processing shown in Figure 8. [6] Corresponds to the steering control system being provided with a first control system and a second control system.

[0073] <Other embodiments> This embodiment can be modified as follows: This embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0074] About Processing Modes The main processing mode is not limited to a utilization state setting processing mode that sets the utilization state of the actuator depending on whether or not an abnormality exists. For example, it may be a mode that determines whether or not an automatic steering request is made. In this case, the sub-processing mode may include a mode that executes automatic steering processing and a mode that executes manual steering processing.

[0075] "Synchronization of execution timing between control devices" In the above embodiment, the processes in the slave processing mode are synchronized between the control devices by executing the process shown in FIG. 9 each time the process of S20 or S24 is executed, but the method for achieving synchronization is not limited to this. For example, the processes in the slave processing mode may be synchronized between the control devices by executing the following process. Each time the utilization status is updated, the PU 22, 52 outputs a signal indicating that the status has been updated. When the PU 22, 52 receives a signal output from another control device, it outputs a signal indicating that the status has been received. Each time the PU 22, 52 receives a signal indicating that the status has been received, it executes the process shown in FIG. 9.

[0076] "About Transition Masters" The transition master does not necessarily have to be the reaction force control device 20 of the main control system. For example, the transition master may be the turning control device 50 of the main control system. Furthermore, for example, the transition master may be set to appropriately switch between the reaction force control device 20 and the turning control device 50 in the main control system, whichever takes the shortest time to transmit the activation state to the other control devices. This can be achieved by setting the reaction force control device 20 as the transition master in states 2 and 5, and setting the turning control device 50 as the transition master in states 3 and 4. That is, for example, when the reaction force control device 20(1) executes the process of S20 in state 2, the signal indicating the activation state is transmitted directly to the reaction force control device 20(2) and the turning control device 50(1) without passing through the other control devices. On the other hand, when the reaction force control device 20(1) executes the process of S20 in state 3, the signal indicating the activation state is transmitted to the turning control device 50(2) via the turning control device 50(1). Therefore, it takes a long time for this signal to be transmitted to steering control device 50(2). Therefore, a configuration is made in which steering control device 50(1) is set as the transition master in state 3. As a result, when steering control device 50(1) executes the processing of S20, the signal indicating the utilization state is transmitted directly to reaction force control device 20(1) and steering control device 50(2) without passing through other control devices. Therefore, it is possible to shorten as much as possible the time required for the signal output by the processing of S20 to be transmitted to each control device.

[0077] "About the condition" If an abnormality occurs in reaction force control device 20(1) or a communication abnormality occurs in the first control system in state 3, it is not essential to transition to state 9. In that case, for example, the state may transition to state 8. Also, for example, the state may transition to a state in which steering actuator At is operated by both steering control devices 50(1), 50(2).

[0078] If an abnormality occurs in reaction force control device 20(2) or a communication abnormality occurs in the second control system in state 4, it is not essential to transition to state 8. In that case, for example, the state may transition to state 9. Also, for example, the state may transition to a state in which both steering control device 50(1) and steering control device 50(2) operate steering actuator At.

[0079] In state 2, if an abnormality occurs in the control by reaction force control device 20(1), it is not essential to transition to state 8. For example, a transition may be made to a state in which steering control device 50(1) operates steering actuator At and reaction force control device 20(2) operates reaction force actuator Ar. Also, in state 2, if an abnormality occurs in the communication of the first control system, it is not essential to transition to state 8. For example, a transition may be made to a state in which steering control device 50(1) operates steering actuator At and reaction force control device 20(2) operates reaction force actuator Ar. Also, for example, a transition may be made to a state in which steering control device 50(1) operates steering actuator At and reaction force control device 20(1) operates reaction force actuator Ar. In these cases, steering control device 50(i) operates steering actuator At in accordance with target steering equivalent angle θp*(i) set in fail-time target value setting process M32(i).

[0080] In state 5, if an abnormality occurs in the control by reaction force control device 20(2), it is not essential to transition to state 9. For example, a transition may be made to a state in which steering control device 50(2) operates steering actuator At and reaction force control device 20(1) operates reaction force actuator Ar. Also, in state 5, if an abnormality occurs in the communication of the second control system, it is not essential to transition to state 9. For example, a transition may be made to a state in which steering control device 50(2) operates steering actuator At and reaction force control device 20(1) operates reaction force actuator Ar. Also, for example, a transition may be made to a state in which steering control device 50(2) operates steering actuator At and reaction force control device 20(2) operates reaction force actuator Ar. In these cases, steering control device 50(i) operates steering actuator At in accordance with target steering equivalent angle θp*(i) set in fail-time target value setting process M32(i).

[0081] "About communication errors" For example, if an abnormality occurs in the intra-system communication line Lc(1) of the first control system, in addition to the operation of the reaction force actuator Ar by the reaction force control device 20(1), the operation of the turning actuator At by the turning control device 50(1) may be stopped. In other words, if an abnormality occurs in the intra-system communication line Lc(1) of the first control system in State 1, a transition to State 7 may be made.

[0082] If an abnormality occurs in communication with the main control system, the main control system may be switched and operation of the reaction force actuator Ar by the reaction force control device 20(i) of the main control system before the switch may be continued. That is, for example, if an abnormality occurs in communication with the first control system in state 1, the second control system may be set as the main control system without transitioning to state 4, and operation of the reaction force actuator Ar by the reaction force control device 20(1) may be continued.

[0083] For example, if an abnormality occurs in the intra-system communication line Lc(2) of the second control system, in addition to the operation of the reaction force actuator Ar by the reaction force control device 20(2), the operation of the turning actuator At by the turning control device 50(2) may be stopped. In other words, if an abnormality occurs in the intra-system communication line Lc(2) of the second control system in State 1, a transition to State 6 may be made.

[0084] If an abnormality occurs in the communication of the sub-control system, the operation of the reaction force actuator Ar by the reaction force control device 20(i) of the sub-control system may continue. That is, for example, if an abnormality occurs in the communication of the second control system in State 1, the operation of the reaction force actuator Ar by the reaction force control device 20(2) may continue without transitioning to State 3.

[0085] "About communication lines" The installation of the communication lines is not limited to that shown in Fig. 1. For example, a communication line may be provided that connects the reaction force control device 20 in one control system with the steering control device 50 in another control system.

[0086] "About the control system" The number of control systems is not limited to two. The number of control systems may be three or more. Specifically, for example, reaction force control devices 20(1) to 20(3) and turning control devices 50(1) to 50(3) may be provided. In that case, for example, if an abnormality occurs in reaction force control device 20(1), reaction force actuator Ar may be operated by reaction force control devices 20(2) and 20(3), and turning actuator At may be operated by turning control devices 50(1) to 50(3).

[0087] "Regarding the process for setting the target steering angle" It is not essential that reaction force control device 20(1) executes target steering equivalent angle setting process M12(1). For example, steering control device 50(1) may execute target steering equivalent angle setting process M12(1). In that case, reaction force control device 20(1) simply transmits steering angle θh(i) to steering control device 50(1).

[0088] It is not essential that the reaction force control device 20(2) executes the target steering equivalent angle setting process M12(2). For example, the steering control device 50(2) may execute the target steering equivalent angle setting process M12(2). In that case, the reaction force control device 20(2) only needs to transmit the steering angle θh(2) to the steering control device 50(2).

[0089] "About the steering operation amount calculation process" The steering operation amount calculation process does not necessarily have to be a process of calculating the target reaction torque Ts* based on the operation amount of feedback control in which the steering torque Th is the control amount. For example, it may be a process of calculating the target reaction torque Ts* in accordance with the assist torque calculated in accordance with the steering torque Th as an input variable.

[0090] "Input variables for the steering operation amount calculation process" It is not essential that the input variable of steering operation amount calculation process M36(i) when control by reaction force control device 20(i) is normal include a signal output by reaction force control device 20(i). The input variable of steering operation amount calculation process M36(i) may be, for example, the target steering equivalent angle θp*(i) set by failure target value setting process M32(i).

[0091] "About sensors" In the above embodiment, the first control system and the second control system are provided with separate rotation angle sensors 30(1), 30(2) for detecting the rotation angle of the reaction force motor 12, but this is not limiting. For example, a rotation angle sensor may be shared between the systems.

[0092] In the above embodiment, the first control system and the second control system are provided with separate rotation angle sensors 60(1), 60(2) that detect the rotation angle of the steering motor 42, but this is not limiting. For example, a rotation angle sensor may be shared between the systems.

[0093] In the above embodiment, the torque sensor 32 is shared between the first control system and the second control system, but this is not limitative. For example, a separate torque sensor may be provided for each control system. In the above embodiment, the steering sensor 62 is shared between the first control system and the second control system, but this is not limitative. For example, a separate steering sensor may be provided for each control system.

[0094] "About the reaction force actuator Ar" It is not essential that the reaction motor 12 provided in the reaction actuator Ar includes a stator coil 16 for each of the multiple control systems. For example, a separate reaction motor may be provided for each control system. Also, for example, one reaction motor may be configured for each of the multiple control systems. Specifically, for example, in the case of four control systems, one reaction motor may be shared between the first and second control systems, and another reaction motor may be shared between the third and fourth control systems. In this case, one reaction motor will include stator coils for two control systems.

[0095] It is not essential that the reaction force actuator Ar is configured so that the outputs controlled by each control system are equal to each other. For example, the rated output of the inverter 18(1) may be K (>1) times the rated output of the inverter 18(2). In that case, for example, the reaction force control device 20(1) may operate the inverter 18(2) in accordance with a value that is "K / (1+K)" times the target reaction force torque Ts*(1). Furthermore, the reaction force control device 20(2) may operate the inverter 18(2) in accordance with a value that is "1 / (1+K)" times the target reaction force torque Ts*(1).

[0096] "About the steering actuator At" It is not essential that steering motor 42 provided in steering actuator At be provided with stator coils 46 for each of the multiple control systems. For example, a separate steering motor may be provided for each control system. Also, for example, one steering motor may be configured for each of the multiple control systems. Specifically, for example, in the case of four control systems, one steering motor may be shared by the first control system and the second control system, and another steering motor may be shared by the third control system and the fourth control system. In that case, one steering motor will be provided with stator coils for the two control systems.

[0097] It is not essential that steering actuator At is configured so that the outputs controlled by each control system are equal to each other. For example, the rated output of inverter 48(1) may be K (>1) times the rated output of inverter 48(2). In that case, for example, steering control device 50(1) may operate inverter 48(2) in accordance with a value that is K / (1+K) times target steering torque Tt*(1). Also, steering control device 50(2) may operate inverter 48(2) in accordance with a value that is 1 / (1+K) times target steering torque Tt*(1). [Explanation of symbols]

[0098] 10...Steering wheel 12...Reaction motor 16...Stator coil 18...Inverter 20...Reaction force control device 40...Steering wheel 42...Steering motor 46...Stator coil 48...Inverter 50...Steering control device

Claims

1. A steering control system including a reaction force actuator that applies a steering reaction force to a steering shaft in a state where power transmission between a steering shaft and steered wheels is interrupted, and a steering actuator that steers the steered wheels, a reaction force control device in which the reaction force actuator is an operation object, and a steering control device in which the steering actuator is an operation object, each of the processing modes of the reaction force control device and the steering control device includes one main processing mode and one or more sub processing modes; each of the reaction force control device and the steering control device is configured to execute processing in the slave processing mode in accordance with a processing result in the main processing mode, and is configured to periodically repeat execution of the processing in the main processing mode and execution of the processing in the slave processing mode; A steering control system configured such that the processing in the main processing mode is executed prior to the periodic execution of the processing in the slave processing mode.

2. the processing in the main processing mode includes a process of selectively setting one of a plurality of utilization states depending on the presence or absence of an abnormality in each of the control devices constituting the steering control system, The steering control system according to claim 1 , wherein the utilization state is a state specified by which control device contributes to the operation of the actuator.

3. the slave processing mode includes a steering assist mode, 3. The steering control system according to claim 2, wherein the processing in the steering assist mode includes processing for applying a reaction force against rotation of the steering shaft by the driver using the reaction force actuator and for operating the steering actuator in response to operation of the steering shaft by the driver.

4. the slave processing mode includes an automatic processing mode; 3. The steering control system according to claim 2, wherein the processing in the automatic processing mode includes at least one of a processing for turning the steered wheels independently of the operation of the steering shaft, a processing for controlling the rotation of the steering shaft, and a processing for fixing the steering shaft.

5. One of the control devices in the steering control system is selectively set as a transition master; 3. The steering control system according to claim 2, wherein control devices other than the transition master are configured to follow the utilization state set by the transition master through processing defined by the main processing mode.

6. a plurality of control systems each including the reaction force control device and the steering control device; 2. The steering control system according to claim 1, wherein the reaction force actuator and the steering actuator are operated by a plurality of control systems.

7. A steering control method applied to a system including a reaction force actuator that applies a steering reaction force to a steering shaft in a state where power transmission between the steering shaft and steered wheels is interrupted, a steering actuator that steers the steered wheels, a reaction force control device in which the reaction force actuator is an operation object, and a steering control device in which the steering actuator is an operation object, each of the processing modes of the reaction force control device and the steering control device includes one main processing mode and one or more sub processing modes; The steering control method includes: each of the reaction force control device and the steering control device executes processing in the slave processing mode in accordance with a processing result in the main processing mode, and periodically repeats execution of the processing in the main processing mode and execution of the processing in the slave processing mode; each of the reaction force control device and the steering control device executing a process in the main processing mode prior to periodically executing a process in the slave processing mode.

Images