Steering control device

Abstract

The steering control device (1) includes a controller including a drive circuit (61a) that performs an action for supplying electric power supplied through connection to at least one of a first power supply and a second power supply to a motor. In a case where a connection state of the drive circuit (61a) is a state of supplying electric power from the first power supply, when an abnormality of the first power supply is detected, a power supply device (80) switches the connection state to transition to a second state of supplying electric power from the second power supply. Further, after the abnormality is detected and before the switching of the connection state is completed, the controller starts an output limiting process of limiting a torque outputtable by the motor compared to before the abnormality of the first power supply is detected.

Description

[0001] Background of the invention Technical Field

[0002] This invention relates to a steering control device.

[0003] Description of related technologies

[0004] For example, the vehicle is equipped with a steering system disclosed in Japanese Unexamined Patent Application Publication No. 2020-83058 (JP 2020-83058 A). The steering system disclosed in JP 2020-83058 A is a so-called steer-by-wire type, in which the power transmission path between the vehicle's steering wheel and the vehicle's turning wheels is separate. The steering system includes a power supply unit. The power supply unit provides power to the components of the steering system (e.g., a reaction force motor, a rotary actuator, and a control device). The power supply unit includes a main power supply and a backup power supply. The backup power supply is used as a backup when the power supply unit malfunctions, i.e., when the main power supply fails or fails.

[0005] Note that the electrical power supplied by the backup power source is limited, and therefore, the steering mechanism performs, for example, an output limiting process that controls the output of the rotary actuator during backup power support. In this way, when the power supply fails, the steering mechanism can continue to rotate the wheel as long as possible with backup power support. Summary of the Invention

[0006] In JP 2020-83058A, the steering mechanism is designed such that even if the rotation of the rotating wheel must continue via a backup power supply, the power limit that can be supplied by the backup power supply will not be exceeded. Here, for the backup power supply in standby mode, it is necessary to reduce the possibility of falling into a situation where output limit processing for the output of the rotation actuator is not performed.

[0007] This invention relates to a steering control device. The steering control device is connected to a first power source installed in a vehicle via a power supply device, the power supply device including a second power source. The steering control device includes a controller, which includes a drive circuit that performs actions to supply power to a motor via connection to at least one of the first and second power sources. The controller is configured to control the operation of the motor by controlling the action of the drive circuit. In a first state where the drive circuit is supplying power from the first power source, upon detecting an anomaly in the first power source, the power supply device switches the connection state to a second state where power is supplied from the second power source. The controller is configured to perform an output limiting process after detecting an anomaly in the first power source, compared to before the anomaly was detected. The output limiting process is a process that limits the torque that can be output by the motor. The output limiting process begins after detecting the anomaly in the first power source and before the switching of the connection state to the second state in response to the detection of the anomaly is completed, the switching of the connection state being performed by the power supply device.

[0008] Using the above configuration, when the power supply completes its switch from the first power supply state to the second state in response to detecting an anomaly in the first power supply, the controller has already begun output limiting processing. In this way, it is possible to prevent the situation where the torque output by the motor is not limited by the controller when the power supply's connection state switch is complete. Therefore, the possibility of falling into the situation where the torque output by the motor is unrestricted when a power supply anomaly is detected can be reduced.

[0009] In the steering control device according to the above aspects, the output limiting process can be a process for limiting the torque output by the motor so that the torque does not exceed the output limiting value, and under the condition that the power performance of the second power supply is lower than the power performance of the first power supply, the output limiting value can be a value less than the power performance limit of the second power supply, the power performance being limited by the power capacity or power voltage of the second power supply.

[0010] Using the above configuration, the likelihood of falling into a situation where the power supply performance exceeds that of the second power supply can be reduced in the second state. In this way, even when an anomaly of the first power supply is detected, motor operation can continue appropriately. This effect is particularly pronounced when the power supply performance of the second power supply is lower than that of the first power supply.

[0011] In the steering control device according to the above aspects, the power supply device may include a power controller configured to switch a connection state in response to detecting an abnormality in the first power supply, such that the connection state transitions to a second state, and the controller may be configured to connect to the power controller to communicate with the power controller via a line, and is configured to obtain information indicating the completion of the connection state switch from the power controller via a line when the connection state transitions to the second state.

[0012] In the above configuration, the controller can determine the state of the power supply unit, such as whether it is in a first state or a second state, based on information obtained from the power controller via the line. In this way, the controller can operate considering the state of the power supply unit. Note that a communication delay occurs in the communication between the controller and the power controller. The causes of this communication delay include, for example, line path errors or communication errors. As an example, consider the following assumption: the controller is configured to determine, based on information obtained from the power controller, that the transition from the connection state to the second state is complete, and then begin limiting the torque that can be output by the motor. In this case, during the communication delay, the transition from the connection state to the second state is completed; however, the controller does not begin limiting the torque that can be output by the motor.

[0013] On the other hand, using the above configuration, when an anomaly in the first power supply is detected, the controller can begin limiting the torque that can be output by the motor earlier than obtaining information from the power controller indicating the completion of the switch from the connection state to the second state. Therefore, in a configuration where the controller and the power controller communicate with each other, the possibility of falling into a situation where the torque that can be output by the motor is unrestricted can be reduced when transitioning to the second state in response to the detection of an anomaly in the first power supply.

[0014] Specifically, in the steering control device according to the above aspects, the controller can be configured to perform output limiting processing when the vehicle's power supply is in an on state that allows connection to a first power supply to enable vehicle operation.

[0015] In the steering control device according to the above aspects, the controller may include a control circuit that performs processing related to output limiting processing, and the control circuit may be configured to be connected to at least one of a first power supply and a second power supply, and regardless of the state of the first power supply, the control circuit is always connected to at least one of the first power supply and the second power supply through a connection circuit included in the power supply device when the vehicle power supply is on.

[0016] Using the above configuration, when an anomaly in the first power supply is detected while the vehicle's power is on, power is continuously supplied to the control circuitry included in the controller. In this case, the control circuitry can appropriately initiate output limiting processing when the first power supply fails.

[0017] The steering control device of the present invention can reduce the possibility of falling into a situation where the torque output by the motor is unrestricted when a power abnormality is detected. Attached Figure Description

[0018] 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 similar reference numerals denote similar elements, and in the drawings:

[0019] Figure 1 This is a diagram illustrating a schematic configuration of the steering system;

[0020] Figure 2 This is a block diagram showing the electrical configuration of the steering system;

[0021] Figure 3 This is a block diagram that specifically illustrates the electrical configuration of the steering unit's rotary side controller.

[0022] Figure 4 This is a block diagram that specifically illustrates the function of the control circuit in the main controller of the rotary side controller;

[0023] Figure 5 This is a diagram illustrating the function of the limiting controller in the control circuit.

[0024] Figure 6 These are diagrams illustrating (a) the power supply voltage, (b) the state of the start switch, (c) the state of the power supply device, and (d) the output limit value in the embodiments, respectively; and

[0025] Figure 7 The diagrams show (a) the power supply voltage, (b) the state of the start switch, (c) the state of the power supply device, and (d) the output limit value in the comparative examples. Detailed Implementation

[0026] The steering control device 1 according to the embodiment will be described. For example... Figure 1As shown, the steering device 2, controlled by the steering control device 1, is configured as a steer-by-wire type steering device for a vehicle. The steering device 2 includes a steering section 4 and a rotating section 6. The steering section 4 is turned by the driver via the vehicle's steering wheel 3. The rotating section 6 rotates the vehicle's left and right steering wheels 5 according to the driver's steering input to the steering section 4. The steering device 2 of this embodiment has a structure in which the power transmission path between the steering section 4 and the rotating section 6 is always mechanically separated. That is, the power transmission path between the steering actuator 12 (described later) and the rotating actuator 31 (described later) is always mechanically separated.

[0027] 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. 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, as a force resisting steering, to the steering wheel 3 via the steering shaft 11. The steering-side motor 13 is connected to the steering shaft 11 via, for example, the steering-side reduction mechanism 14 formed by a worm and a worm wheel. For example, a three-phase brushless motor is used for the steering-side motor 13 in this embodiment.

[0028] The rotating part 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 at a predetermined cross angle. The rack and pinion mechanism 24 is formed by the meshing of pinion teeth 21a formed on the pinion shaft 21 and rack teeth 22a formed on the rack shaft 22. That is, the pinion shaft 21 corresponds to a rotation axis whose rotation angle can be converted into the rotation position of the rotating wheel 5. The rack housing 23 houses the rack and pinion mechanism 24. One end of the pinion shaft 21 opposite to the end connected to the rack shaft 22 protrudes from the rack housing 23. In addition, both ends of the rack shaft 22 protrude from both ends of the rack housing 23 in the axial direction. The connecting rod 26 is connected to both ends of the rack shaft 22 via rack ends 25 formed by ball joints. The distal end of the connecting rod 26 is connected to a joint (not shown), to which the left rotating wheel and the right rotating wheel 5 are assembled.

[0029] The rotating part 6 includes a rotation actuator 31. The rotation actuator 31 includes a rotating-side motor 32 as a drive source, a transmission mechanism 33, and a conversion mechanism 34. The rotating-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 rotating-side motor 32 transmits rotation to the conversion mechanism 34 via the transmission mechanism 33, for example, a belt drive mechanism. The transmission mechanism 33 converts the rotation of the rotating-side motor 32 into the reciprocating motion of the rack shaft 22 via the conversion mechanism 34, for example, a ball screw mechanism. For the rotating-side motor 32 in this embodiment, a three-phase brushless motor is used, for example. In this embodiment, the rotating-side motor 32 is an example of a motor.

[0030] In the steering device 2 constructed as described above, in response to the driver's steering operation, the rotation angle of the rotating wheel 5 is changed by applying the motor torque from the rotary actuator 31 as a rotational force to the rack shaft 22. In this case, the steering actuator 12 applies a steering reaction force to the steering wheel 3 against the driver's steering. That is, in the steering device 2, the steering torque Th required to turn the steering wheel 3 is changed by the steering reaction force, which is the motor torque applied from the steering actuator 12.

[0031] Incidentally, the pinion shaft 21 is provided so that the rack shaft 22 can be supported together with the pinion shaft 21 within the rack housing 23. That is, the rack shaft 22 is movably supported in the axial direction and pressed against the pinion shaft 21 via a support mechanism (not shown) provided in the steering device 2. In this way, the rack shaft 22 is supported within the rack housing 23. Note that another support mechanism can be provided to support the rack shaft 22 on the rack housing 23 without using the pinion shaft 21.

[0032] like Figure 1 As shown, the steering-side motor 13 and the rotation-side motor 32 are connected to the steering control unit 1. The steering control unit 1 controls the operation of motors 13 and 32. In this way, the steering control unit 1 controls the operation of the steering unit 2 to exhibit the desired function of a steering unit of the steer-by-wire type.

[0033] The detection results from various sensors are input 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, and a vehicle speed sensor 44.

[0034] A torque sensor 41 is located at a portion of the steering shaft 11 closer to the steering wheel 3 than the steering-side deceleration mechanism 14. The torque sensor 41 detects the steering torque Th, which is the value indicating the torque applied to the steering shaft 11 by the driver's steering operation. The steering torque Th is detected relative to the torsion of a torsion bar 41a located in the middle of the steering shaft 11. A steering-side rotation angle sensor 42 is located in the steering-side motor 13. The steering-side rotation angle sensor 42 detects the rotation angle θa, which is the angle of the rotation axis of the steering-side motor 13, within a 360-degree range. A rotation-side rotation angle sensor 43 is located in the rotation-side motor 32. The rotation-side rotation angle sensor 43 detects the rotation angle θb, which is the angle of the rotation axis of the rotation-side motor 32, within a 360-degree range. A vehicle speed sensor 44 detects the vehicle speed V, which is the vehicle's travel speed.

[0035] Electrical configuration of steering control unit 1

[0036] like Figure 2As shown, the steering control device 1 includes a steering-side controller 50 that controls the power supply to the steering-side motor 13 and a rotation-side controller 60 that controls the power supply to the turning-side motor 32. The steering-side controller 50 and the rotation-side controller 60 send and receive information to each other via a local network 70 (e.g., serial communication). The steering-side controller 50 is configured as part of the steering unit 4. Additionally, the rotation-side controller 60 is configured as part of the turning unit 6.

[0037] The steering-side controller 50 includes a central processing unit (CPU) and a memory (not shown), and the CPU executes programs stored in the memory at predetermined calculation cycles. Various processes are performed in this manner. The calculation cycle of the steering-side controller 50 can be set by considering either the calculation cycle of the power controller 88 (described later) or the communication time period of the dedicated signal line 90 (described later). For example, the calculation cycle of the steering-side controller 50 is designed to be shorter than either the calculation cycle of the power controller 88 (described later) or the communication time period of the dedicated signal line 90 (described later).

[0038] As a control system formed by combining a CPU and memory to perform various processes, the steering-side controller 50 is configured to have two systems: a main controller 50a and a sub-controller 50b. In this embodiment, the steering-side controller 50 operates in a master-slave control method, with the main controller 50a as the master controller and the sub-controller 50b as the slave controller. The same applies to the rotation-side controller 60. That is, as a controller formed by combining a CPU and memory to perform various processes, the rotation-side controller 60 is configured to have two systems: a main controller 60a and a sub-controller 60b, and both controllers operate in a master-slave control method. The controllers 50a and 50b of the steering-side controller 50 and the controllers 60a and 60b of the rotation-side controller 60 are configured to communicate with each other via a local network 70.

[0039] Each of the controllers 50a and 50b of the steering-side controller 50 calculates a reaction force control quantity based on various information, which is the target steering reaction force of the steering wheel 3 to be generated by the steering-side motor 13. The various information includes, for example, the detection results of the various sensors described above and information obtained from the rotation-side controller 60 via the local network 70. Each of the controllers 50a and 50b controls the power supply to the steering-side motor 13 based on the reaction force control quantity. Furthermore, each of the controllers 60a and 60b of the rotation-side controller 60 calculates a rotation control quantity based on various information, which is the target rotational force to be generated by the rotation-side motor 32. The various information includes, for example, the detection results of the various sensors described above and information obtained from the steering-side controller 50 via the local network 70. Each of the controllers 60a and 60b controls the power supply to the rotation-side motor 32 based on the rotation control quantity.

[0040] The main power supply 45, serving as the primary power source, is connected to the steering control unit 1, i.e., the steering unit 2. The main power supply 45 is, for example, a secondary battery installed in the vehicle. The main power supply 45 serves as a power source for supplying power to operate the motors 13 and 32, and also serves as a power source for supplying power to operate the steering control unit 1 (i.e., the steering unit 2).

[0041] A vehicle start switch 46, such as an ignition switch, is provided between the steering device 2 and the main power supply 45. Of the two power lines L1 and L2 connecting the steering device 2 to the main power supply 45, the start switch 46 is located in the middle of the power line L2, which branches off from the connection point P0 of power line L1. Operating the start switch 46 activates various functions, allowing the vehicle to be operated by activating the drive source (e.g., the engine) for vehicle movement. Operation of the start switch 46 causes power line L2 to become either on or off. In this embodiment, the operating state of the steering device 2, which exhibits the desired function of a steering device of the steer-by-wire type, is associated with the operating state of the vehicle. Although power line L1 is essentially always on, it indirectly changes to an on or off state as a function of the steering device 2, depending on its operating state. That is, the operating state of the steering device 2 is associated with whether each of the power lines L1 and L2 is on, which is the state of the power supply from the main power supply 45.

[0042] In the steering device 2, each of the power lines L1 and L2, i.e., the main power supply 45, is connected to the steering-side controller 50, particularly the main controller 50a, via the power supply device 80. Furthermore, each of the power lines L1 and L2, i.e., the main power supply 45, is directly connected to the steering-side controller 50, particularly the sub-controller 50b, without the power supply device 80 being inserted in between. The same applies to the rotation-side controller 60, and each of the power lines L1 and L2, i.e., the main power supply 45, is connected to the rotation-side controller 60, particularly the main controller 60a, via the power supply device 80. Furthermore, each of the power lines L1 and L2, i.e., the main power supply 45, is directly connected to the rotation-side controller 60, particularly the sub-controller 60b, without the power supply device 80 being inserted in between. That is, in this embodiment, the steering-side controller 50 and the rotation-side controller 60 are configured to share a single power supply 80. The power supply device 80 is configured to communicate with the main controllers 50a and 60a of the steering-side controller 50 and the rotation-side controller 60 via a dedicated signal line 90.

[0043] Connection of power cords L1 and L2

[0044] Figure 3 The power supply configuration is shown in detail. Here, the configuration of the steering side controller 60 will be described primarily. The configuration of the steering side controller 50 is essentially the same as that of the steering side controller 60.

[0045] like Figure 3 As shown, power from the main power supply 45 is supplied to the drive circuit 61a of the main controller 60a via power line L11, which branches off from the connection point P11 of power line L1. The drive circuit 61a is a circuit that handles large amounts of power and includes, for example, an inverter that converts the DC power from the main power supply 45 into AC power. Power from the main power supply 45 is supplied to the control circuit 62a of the main controller 60a via power line L21, which branches off from the connection point P12 of power line L2. The control circuit 62a is a circuit for controlling the steering-side motor 13 and includes, for example, a CPU and a memory.

[0046] Furthermore, power from the main power supply 45 is supplied to the drive circuit 61b of the sub-controller 60b via power line L12, which branches off from the connection point P11 of power line L1. Drive circuit 61b has the same configuration as drive circuit 61a. Power from the main power supply 45 is also supplied to the control circuit 62b of the sub-controller 60b via power line L22, which branches off from the connection point P12 of power line L2. Control circuit 62b has the same configuration as control circuit 62a.

[0047] The steering-side controller 50 has a configuration corresponding to that of the steering-side controller 60. Specifically, in the steering-side controller 50, the main controller 50a has components corresponding to the drive circuit 61a and the control circuit 62a. In the steering-side controller 50, the sub-controller 50b has components corresponding to the drive circuit 61b and the control circuit 62b.

[0048] Construction of power supply device 80

[0049] like Figure 3 As shown, the power supply device 80 includes an auxiliary power supply 81 as a second power supply, a circuit 82, switches 83, 84, 85, diodes 86, 87, and a power controller 88.

[0050] The auxiliary power supply 81 is, for example, a capacitor that functions as a secondary battery. The auxiliary power supply 81 serves as a power source for operating the steering-side motor 32 and also as a power source for operating the steering-side controller 60. This also applies to the steering unit 4, where the auxiliary power supply 81 serves as a power source for supplying power to the steering-side motor 13 and also as a power source for supplying power to the steering-side controller 50. The main power supply 45 and the auxiliary power supply 81 differ in their power performance related to the amount of power that can be supplied. The auxiliary power supply 81 is configured to have a smaller power capacity than the main power supply 45, which is the amount of charge that can be stored to supply power. The auxiliary power supply 81 is also configured to have a smaller power supply voltage than the main power supply 45, which is the voltage used when supplying power. In other words, the power performance of the auxiliary power supply 81 is configured to be lower than that of the main power supply 45.

[0051] As indicated by the following formula (A), the power supply voltage V2 of the auxiliary power supply 81 is set to a value that is higher than the voltage V0 required for proper operation of the motors 13, 32 or the controllers 50, 60 and lower than the power supply voltage V1 of the main power supply 45.

[0052] V1>V2>V0…(A)

[0053] Inside the power supply unit 80, the auxiliary power supply 81 is connected to the connection point P11 of the power supply line L11 via a power line L111 branching from the connection point P13 of the power supply line L11. Furthermore, inside the power supply unit 80, the auxiliary power supply 81 is connected to the connection point P11 of the power supply line L11 via a power line L112 branching from the connection point P14 of the power supply line L11. Note that connection point P14 is downstream, meaning that connection point P14 is closer to the steering-side controller 60 than connection point P13. The auxiliary power supply 81 is used to assist in the power supply to the steering-side controller 60 based on the state of the power supply from the main power supply 45. In this embodiment, the auxiliary power supply 81 has the function of providing backup power to the steering-side controller 60 in place of the main power supply 45 when the power supplied by the main power supply 45 decreases. This also applies to the steering-side controller 50. That is, the auxiliary power supply 81 has the function of providing backup power to the steering-side controller 50 in place of the main power supply 45 when the power supplied by the main power supply 45 decreases.

[0054] Circuit 82 switches the connection state to power line L11, allowing auxiliary power supply 81 to be charged and discharged. Additionally, circuit 82 switches the connection state to power line L11 to disconnect auxiliary power supply 81, preventing charge from discharging from auxiliary power supply 81.

[0055] Switch 83 is located in the middle of the power line L11 within the power supply unit 80. Switch 83 is upstream, meaning it is closer to the main power supply 45 than connection point P13. Switch 83 opens and closes the power line L11.

[0056] Switch 84 is located in the middle of power line L111 within power supply unit 80. Switch 84 opens and closes power line L111. Switch 85 is located in the middle of power line L112 within power supply unit 80. Switch 85 opens and closes power line L112.

[0057] Connection point P15 is located on power line L112. Inside the power supply unit 80, connection point P15 of power line L112 and connection point P16 of power line L21 are connected via power line L113.

[0058] Diode 86 is positioned in the middle of power line L113. The cathode of diode 86 is connected to connection point P16 of power line L21. The anode of diode 86 is connected to connection point P15 of power line L113.

[0059] Diode 87 is positioned in the middle of power line L21. The cathode of diode 87 is connected to connection point P16 of power line L21. The anode of diode 87 is connected to connection point P12 of power line L21.

[0060] Diodes 86 and 87 allow power to flow from the anode to the cathode and restrict power flow from the cathode to the anode. Diodes 86 and 87 form an OR circuit that supplies power to the control circuit 62a from the main power supply 45 or the auxiliary power supply 81, which has the higher supply voltage. The OR circuit formed by diodes 86 and 87 is a so-called wired OR. The OR circuit formed by diodes 86 and 87 corresponds to a selection circuit that selects the power from the main power supply 45 or the auxiliary power supply 81 with the higher supply voltage to supply power to the rotation-side controller 60. In this embodiment, the OR circuit is an example of a connection circuit.

[0061] Functions of power controller 88

[0062] The power controller 88 includes a central processing unit (CPU) and memory (not shown), and the CPU executes one or more programs stored in the memory at predetermined calculation cycles. In this way, various processes are performed.

[0063] Specifically, the power controller 88 controls the switching of the connection state of the control circuit 82 and controls the opening and closing of switches 83, 84, and 85. The power controller 88 monitors the voltage of the main power supply 45. The power controller 88 has the function of detecting the voltage of the power supplied to the power supply device 80 through the power line L11 as the power supply voltage Vb of the main power supply 45. The power supply voltage Vb is the power supply voltage at the connection point P11 of the power line L11. As shown in the following equation (B), when the power supply voltage Vb of the main power supply 45 is lower than the threshold voltage Vth, the power controller 88 determines that the power supply voltage Vb of the main power supply 45 has dropped. The threshold voltage Vth is a reference used to determine the voltage drop of the main power supply 45 and is set based on the voltage V0 required for proper operation of the motors 13, 32 or the controllers 50, 60. In this embodiment, the threshold voltage Vth is set to the same value as the voltage V0.

[0064] Vb <Vth…(B)

[0065] When no voltage drop in the main power supply 45 is detected, the power controller 88 maintains switches 83 and 84 in the closed (on) state and switch 85 in the open (off) state. Furthermore, when a voltage drop in the main power supply 45 is detected, the power controller 88 switches 83 and 84 from the closed (on) state to the open (off) state. Then, the power controller 88 switches 85 from the open (off) state to the closed (on) state.

[0066] Specifically, when the power supply voltage Vb of the main power supply 45 does not drop, switches 83 and 84 remain in the closed state (switch on), and switch 85 remains in the open state (switch off). For example, for the rotating part 6, power from the main power supply 45 is supplied to the drive circuit 61a in the rotating side controller 60 via power line L11. The auxiliary power supply 81 is charged by power from the main power supply 45 via power line L111.

[0067] When the start switch 46 is turned on, and the main power supply voltage Vb of the main power supply 45 does not drop, power from the main power supply 45 is supplied to the control circuit 62a in the rotation-side controller 60 via power line L21. Incidentally, since the main power supply voltage Vb of the main power supply 45 is set to a higher voltage V1 than the auxiliary power supply voltage V2 of the auxiliary power supply 81, power from the auxiliary power supply 81 is essentially not supplied to the rotation-side controller 60 via power line L113 and a portion of power line L21. Furthermore, diode 86 prevents power from the main power supply 45, which has already been transferred through power line L21, from flowing into the auxiliary power supply 81 via power line L113.

[0068] When an anomaly occurs in the main power supply 45 (e.g., failure or malfunction) and the main power supply voltage Vb drops below the auxiliary power supply voltage V2, power from the auxiliary power supply 81 is immediately supplied to the control circuit 62a in the rotary side controller 60 via a portion of power lines L113 and L21. This is because the auxiliary power supply voltage V2 becomes higher than the voltage generated on power line L2. Even if the power supply from the main power supply 45 to the rotary side controller 60 is interrupted due to a failure of the main power supply 45, backup power supply to the control circuit 62a is provided via the auxiliary power supply 81.

[0069] When the power supply voltage Vb of the main power supply 45 drops further and falls below the threshold voltage Vth, switches 83 and 84 switch from the closed state (on) to the open state (off). Then, switch 85 switches from the open state (off) to the closed state (on). In this way, power from the auxiliary power supply 81 is supplied to the drive circuit 61a in the rotation-side controller 60 via power lines L112 and a portion of power line L11. This is because, due to a fault in the main power supply 45, the power supply voltage V2 of the auxiliary power supply 81 becomes higher than the voltage generated on power line L11. Therefore, even if the power supply from the main power supply 45 to the rotation-side controller 60 is interrupted due to a fault in the main power supply 45, the auxiliary power supply 81 provides backup power to the drive circuit 61a in the rotation-side controller 60.

[0070] In this situation, the power controller 88 generates a backup switchover completion flag FLG as information indicating the completion of the switchover to a state where the power supply is supported by the auxiliary power supply 81. Subsequently, the power controller 88 outputs the backup switchover completion flag FLG to the rotating side controller 60, i.e., the main controller 60a, via a dedicated signal line 90. The backup switchover completion flag FLG indicates that due to a failure of the main power supply 45, switches 83 and 84 have completed the switchover from their closed state (on) to their open state (off), and switch 85 has completed the switchover from its open state (off) to its closed state (on). In this way, the rotating side controller 60 can determine that the power supply unit 80 is in a state where the power supply is supported by the auxiliary power supply 81.

[0071] Incidentally, it is conceivable to replace switch 85 with a diode on power line L112. In this way, when the main power supply 45 fails, power from auxiliary power supply 81 is immediately supplied to drive circuit 61a. However, the diode generates power loss. Therefore, from the viewpoint of suppressing the consumption of auxiliary power supply 81, switch 85 is replaced with diode on power line L112 to supply power to drive circuit 61a, which requires greater power.

[0072] It is also conceivable to replace diode 86 with a switch on power line L113. However, in this case, there is a concern that the time from when the power supply from main power supply 45 is interrupted due to a failure of main power supply 45 to when the switch on power line L113 switches from off to on is very short. Therefore, during the time period before the switch on power line L113 switches from off to on, there is a possibility that control circuit 62a may be reset due to a momentary interruption in the power supply to control circuit 62a. In this regard, when diode 86 is placed on power line L113, when the main power supply 45 fails, power from auxiliary power supply 81 is immediately supplied to control circuit 62a through power line L113 and a portion of power line L21. Since the power supply to control circuit 62a is uninterrupted, control circuit 62a will not be reset due to a drop in power supply voltage.

[0073] Then, in the rotation-side controller 60, control circuit 62a monitors the voltage of the main power supply 45. Control circuit 62a has the function of detecting the voltage of the power supplied to drive circuit 61a through power line L11 as the power supply voltage Vig1 of the main power supply 45. Power supply voltage Vig1 is the power supply voltage at connection point P14 of power line L11. In addition, control circuit 62b monitors the voltage of the main power supply 45. Control circuit 62b has the function of detecting the voltage of the power supplied through power line L22 as the power supply voltage Vig2 of the main power supply 45. Power supply voltage Vig2 is the power supply voltage at connection point P12 of power line L21. Similarly, control circuit 52b included in the main controller 50a of the steering-side controller 50, which has the same configuration as the rotation-side controller 60, has the function of detecting the voltage of the supplied power supplied to drive circuit 51a through the power line corresponding to power line L11 as the power supply voltage of the main power supply 45. Furthermore, the control circuit 52b included in the sub-controller 50b of the steering side controller 50 has the function of detecting the voltage of the power supplied through the power line corresponding to the power line L22 as the power supply voltage of the main power supply 45.

[0074] Functions of the main controller 60a of the rotating side controller 60

[0075] Figure 4 Some processes performed by the control circuit 62a of the main controller 60a of the rotation side controller 60 are shown. Figure 4 The illustrated processes demonstrate each type of process executed by a CPU that executes a program stored in memory. In this embodiment, the rotation-side controller 60, i.e., the main controller 60a, is an example of a controller.

[0076] like Figure 4 As shown, a start signal Sig is input to the control circuit 62a. The start signal Sig is a signal indicating the on / off state of the start switch 46. When it is determined based on the start signal Sig that the start switch 46 is in the off state, the control circuit 62a stops controlling the operation of the rotating side motor 32. That is, when the start switch 46 is in the off state, the rotating side controller 60 cannot reflect the state of the disengaged steering section 4 to the state of the rotating section 6.

[0077] On the other hand, when the start switch 46 is determined to be in the ON state based on the start signal Sig, the control circuit 62a executes control for operating the rotation-side motor 32. That is, when the start switch 46 is in the ON state, the control circuit 62a executes rotation-side control of the steering device 2 of the steer-by-wire type when energized, so that the state of the steering section 4 in the disengaged state is reflected in the state of the rotation section 6. In this case, the control circuit 62a performs the following operation.

[0078] Normal rotation side control

[0079] Specifically, vehicle speed V, rotation angle θb, actual rotational current value Ib, steering angle θs, power supply voltage Vig1, and standby switching completion flag FLG are input to control circuit 62a. The actual rotational current value Ib is obtained from drive circuit 61a. Drive circuit 61a includes a current sensor (not shown). The current sensor detects the actual rotational current value Ib, which is obtained based on the current value of each phase of the rotational motor 32 flowing through the connection line between drive circuit 61a and the motor coils of each phase of the rotational motor 32. The current sensor obtains the voltage drop across the shunt resistor on the source side of each switching element in the inverter included in drive circuit 61a, which is configured correspondingly to the rotational motor 32. The steering angle θs is obtained from steering side controller 50 via local network 70. Steering side controller 50 converts the rotation angle θa into an integrated angle encompassing a range exceeding 360 degrees, for example, by counting the revolutions of steering side motor 13 from the steering neutral position, which is the position of steering wheel 3 when the vehicle is traveling straight. The steering-side controller 50 calculates the steering angle θs by multiplying the integrated angle obtained from the conversion by a conversion factor based on the speed ratio of the steering-side reduction gear 14. The control circuit 62a controls the drive of the drive circuit 61a based on the vehicle speed V, rotation angle θb, actual rotation-side current value Ib, steering angle θs, power supply voltage Vig1, and standby switching completion flag FLG.

[0080] The control circuit 62a includes a pinion angle calculator 101, a pinion angle feedback controller (“pinion angle F / B controller” in the figure) 102, a limit controller 103, and a power-on controller 104.

[0081] The rotation angle θb is input to the pinion angle calculator 101. The pinion angle calculator 101 converts the rotation angle θb into an integrated angle encompassing a range exceeding 360 degrees, for example, by counting the number of revolutions of the rotating-side motor 32 starting from the rack neutral position (i.e., the position of the rack shaft 22 when the vehicle is traveling straight). The pinion angle calculator 101 calculates the pinion angle θp, which is the actual rotation angle of the pinion shaft 21, by multiplying the integrated angle obtained from the 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. The resulting pinion angle θp is output to the pinion angle feedback controller 102. Note that in some cases, the pinion angle θp may also be output to the steering-side controller 50.

[0082] Vehicle speed V, steering angle θs, and pinion angle θp are input to pinion angle feedback controller 102. Pinion angle feedback controller 102 calculates the rotational force command value Tt* as the rotational control quantity through feedback control of the pinion angle θp, such that the pinion angle θp follows the steering angle θs, which is the target angle θp* of the pinion. The obtained rotational force command value Tt* is then output to energized controller 104.

[0083] The power supply voltage Vig1 and the standby switching completion flag FLG are input to the limit controller 103. The limit controller 103 calculates the output limit value Ilim based on the power supply voltage Vig1 and the standby switching completion flag FLG. The output limit value Ilim is a value used to limit the amount of current supplied to the rotating side motor 32. That is, the output limit value Ilim is a value used to limit the torque to be output to the rotating side motor 32. The output limit value Ilim is calculated to vary according to the voltage of the main power supply 45, i.e., the state of the power supply unit 80. The resulting output limit value Ilim is output to the power-on controller 104.

[0084] The rotational force command value Tt*, rotation angle θb, actual rotational current value Ib, and output limit value Ilim are input to the power controller 104. The power controller 104 calculates the current command value Ib* of the rotational motor 32 based on the rotational force command value Tt*. The power controller 104 performs limiting processing to limit the current command value Ib* based on the output limit value Ilim. In this case, the power controller 104 compares the current command value Ib* with the output limit value Ilim. When the absolute value of the current command value Ib* exceeds the output limit value Ilim, the power controller 104 calculates a value obtained by limiting the current command value Ib* to the output limit value Ilim and uses this value as the final current command value Ib*. Furthermore, when the absolute value of the current command value Ib* is equal to or less than the output limit value Ilim, the power controller 104 calculates a value obtained based on the rotational force command value Tt* as the final current command value Ib*.

[0085] Then, the power-on controller 104 obtains the deviation between the final current command value Ib* and the current value on the dq coordinate obtained by converting the actual current value Ib on the rotating side based on the rotation angle θb, and calculates a drive signal Sm for driving the drive circuit 61a to eliminate this deviation. The drive signal Sm is a gate on / off signal that defines the on / off state of each switching element of the inverter included in the drive circuit 61a. The resulting drive signal Sm is output to the drive circuit 61a. In this way, drive power is supplied to the rotating side motor 32 according to the drive signal Sm from the drive circuit 61a. Then, the rotating side motor 32 rotates by a certain angle according to the rotation force command value Tt*.

[0086] Limit the function of controller 103

[0087] Limit controller 103 monitors the voltage of the main power supply 45 used for normal rotational side control. As shown in equation (C), when the detected power supply voltage Vig1 of the main power supply 45 is less than the threshold voltage Vth, limit controller 103 determines that the power supply voltage Vb of the main power supply 45 has decreased. The threshold voltage Vth has the same value as the threshold voltage Vth in equation (B) above, that is, the same value as the voltage V0.

[0088] Vig1 <Vth…(C)

[0089] When no voltage drop is detected in the main power supply 45, the limit controller 103 determines that the power supply device 80 is in a normal state, which is the first state of supplying power from the main power supply 45. In the power supply device 80, the normal state refers to the state in which switches 83 and 84 are switched to the closed state (on) and switch 85 is switched to the open state (off).

[0090] Furthermore, when no standby switchover completion flag (FLG) is input after a voltage drop in the main power supply 45 is detected, the limit controller 103 determines that the power supply unit 80 is in a transition state before completing the transition to the standby state. In the power supply unit 80, the standby transition state refers to a state in which switches 83 and 84 switch from the closed state (switch on) to the open state (switch off), and then switch 85 is in an intermediate state between the open state (switch off) and the closed state (switch on).

[0091] Furthermore, when a standby switching completion flag FLG is input after a voltage drop in the main power supply 45 is detected, the limit controller 103 determines that the power supply device 80 has completed the transition to the standby state, which is the second state. In the power supply device 80, the state in which the transition to the standby state is completed refers to the state in which switches 83 and 84 switch from the closed state (switch on) to the open state (switch off), and switch 85 switches from the open state (switch off) to the closed state (switch on).

[0092] After detecting a voltage drop in the main power supply 45, the limit controller 103 requires a certain amount of time before inputting the backup switch completion flag FLG, which indicates the completion of the switch from the state of the power supply unit 80 to the state of backup power supply from the auxiliary power supply 81. This is because communication delays occur on the dedicated signal line 90 due to factors such as line path or communication errors. For this reason, a certain amount of time is required before the backup switch completion flag FLG output by the power controller 88 is input to the rotating side controller 60 (e.g., in...). Figure 6(c) "Communication time period"). Another reason is that in the power controller 88, processing related to the switching of switches 83, 84, and 85 is performed over multiple calculation cycles. For this reason, in the power supply unit 80, some time is required before the switching of switches 83, 84, and 85 is completed (e.g., Figure 6 (as in (a) "approximately tens of milliseconds"). Therefore, for the standby switchover completion flag FLG, for example, there is a time difference between the input and output of "approximately tens of milliseconds" and "communication period". The limit controller 103 is configured to take into account the time difference between the input and output of the standby switchover completion flag FLG when determining the state of the power supply device 80.

[0093] Then, as Figure 5 As shown, the limit controller 103 calculates the output limit value Ilim based on the state of the power supply device 80, which can be determined by considering the time difference between the input and output of the standby switch completion flag FLG. When the power supply voltage Vig1 is equal to or higher than the threshold voltage Vth, the limit controller 103 determines that the power supply device 80 is in a normal state. In this case, the limit controller 103 calculates the maximum value Imax as the output limit value Ilim. The maximum value Imax is set as a limit value of the torque that can be output by the rotating side motor 32, for example, it is set as the rated current value. That is, the main controller 60a performs normal output limit processing through the function of the control circuit 62a, which allows the rotating side motor 32 to generate torque that reaches the output limit.

[0094] Furthermore, when the power supply voltage Vig1 is less than the threshold voltage Vth and no standby switchover completion flag FLG is input, the limit controller 103 determines that the power supply unit 80 is in a standby switchover state. In this case, the limit controller 103 calculates a minimum value Imin as the output limit value Ilim. The minimum value Imin is a value less than the maximum value Imax. From the viewpoint of the amount of current that can be supplied to the rotating side motor 32 when the main power supply 45 fails, the minimum value Imin is set to a relatively small value within the range of power supply performance limitations below that of the auxiliary power supply 81. That is, the main controller 60a performs output limit processing during standby switchover through the function of the control circuit 62a, and the output limit processing limits the torque that the rotating side motor 32 can output compared to before the main power supply 45 fails.

[0095] Furthermore, when the power supply voltage Vig1 is less than the threshold voltage Vth and the standby switching completion flag FLG is input, the limit controller 103 determines that the power supply unit 80 has completed the transition to the standby state. In this case, the limit controller 103 calculates the standby period limit value Ibu as the output limit value Ilim. The standby period limit value Ibu is less than the maximum value Imax and greater than the minimum value Imin. From the viewpoint of the amount of current that can be supplied to the rotating side motor 32 when the main power supply 45 fails, the standby period limit value Ibu is set to a value within a range greater than the minimum value Imin in the range of power supply performance limits below those of the auxiliary power supply 81. That is, the main controller 60a performs the output limit processing during the standby period through the function of the control circuit 62a, which allows the generation of the largest possible torque while limiting the torque that can be output by the rotating side motor 32 compared to before the main power supply 45 fails. For example, the limit controller 103 calculates an appropriate value as the standby period limit value Ibu based on the state of the steering device 2, such as the internal temperature of the steering control device 1, the operating state of the rotating side motor 32, and the remaining power of the auxiliary power supply 81.

[0096] Regarding the sub-controller 60b of the steering side controller 60, even when the start switch 46 is on, the control circuit 62b ceases control for operating the steering side motor 32 when the main power supply 45 fails. This is because the sub-controller 60b is not connected to the auxiliary power supply 81 of the power supply unit 80. That is, when normal steering side control is performed while the main power supply 45 is not faulty, the control circuit 62b performs the same processing as the control circuit 62a. Furthermore, the main controller 50a of the steering side controller 50 is connected to the auxiliary power supply 81 of the power supply unit 80 in the same manner as the main controller 60a of the steering side controller 60. That is, the main controller 50a may be configured to have a limiting controller with the same function as the main controller 60a, or it may be configured without a limiting controller. Moreover, the sub-controller 50b of the steering side controller 50 is not connected to the auxiliary power supply 81 of the power supply unit 80 in the same manner as the sub-controller 60b of the steering side controller 60. That is, the sub-controller 50b can be configured to perform the same processing as that performed by the main controller 50a while the main power supply 45 is not faulty.

[0097] Operation of this embodiment

[0098] For example, Figure 6Figures (a) and (b) show the power supply voltage Vb monitored by the power controller 88 and the power supply voltage Vig1 monitored by the main controller 60a of the rotary side controller 60 as a function of time t when the start switch 46 is in the ON state. When the start switch 46 is in the ON state, the power supply voltages Vb and Vig1 remain essentially constant at the power supply voltage V1 unless the main power supply 45 fails.

[0099] In this case, such as Figure 6 As shown in (c) and (d), the main controller 60a determines the state of the power supply unit 80 and calculates the output limit value Ilim. The main controller 60a determines that the state of the power supply unit 80 is not a standby state (“NON-BU” in the figure). The main controller 60a calculates the maximum value Imax as the output limit value Ilim. That is, the main controller 60a is in the state of performing normal output limit processing. As a result, the rotating side motor 32 is allowed to generate torque that reaches the output limit of the rotating side motor 32.

[0100] Subsequently, as Figure 6 As shown in (a), when the main power supply 45 fails (“Power Failure” in the figure), the power supply voltages Vb and Vig1 drop below the threshold voltage Vth, for example, to zero. Such voltage drops are detected by monitoring the power controller 88 and the main controller 60a.

[0101] In this case, such as Figure 6 As shown in (c) and (d), the main controller 60a determines the state of the power supply unit 80 and calculates the output limit value Ilim. The main controller 60a confirms that the state of the power supply unit 80 is not a standby state (“NON-BU” in the figure) until the standby switchover complete flag FLG is input. Here, the time period before the standby switchover complete flag FLG is input (“switchover complete” in the figure) corresponds to ( Figure 6 In (a), "approximately tens of milliseconds" plus ( Figure 6 The "communication time period" in (c) refers to the time period during which the power supply unit 80 is not in standby mode, as determined by the main controller 60a. The main controller 60a calculates a minimum value Imin as the output limit value Ilim. That is, the main controller 60a is in a state of performing output limit processing when performing standby transition. As a result, the rotating side motor 32 is in a state where the torque it can output is limited compared to before the main power supply 45 failed.

[0102] Then, as Figure 6 As shown in (c), when the standby switchover complete flag FLG is input ("FLG input" in the figure), the main controller 60a determines that the power supply unit 80 is in standby state ("BU" in the figure).

[0103] Subsequently, as Figure 6 As shown in (d), the main controller 60a calculates the standby period limit value Ibu as the output limit value Ilim. That is, the main controller 60a is in a state of performing standby output limit processing. As a result, the rotating side motor 32 is in a state that allows the torque that can be output compared to before the failure of the main power supply 45 to be limited while generating the largest possible torque.

[0104] According to this embodiment, when the power supply device 80 completes the switch from the connected state to the standby state in response to a fault in the main power supply 45, the main controller 60a has already started the output limiting process during the standby transition.

[0105] Effects of the implementation method

[0106] (1) In this embodiment, when the power supply device 80 is switched from the connected state to the standby state in response to a failure of the main power supply 45, the occurrence of an unrestricted torque output by the rotating side motor 32 can be suppressed. Therefore, even when the main power supply 45 fails, the possibility of falling into the situation where the torque output by the rotating side motor 32 is unrestricted can be reduced.

[0107] (2) In this embodiment, when the power performance of the auxiliary power supply 81 is lower than that of the main power supply 45, the minimum value Imin of the output limit value Ilim is set to a value within the range of the power performance limit of the auxiliary power supply 81. In this way, when the power supply device 80 is in standby mode, the possibility of falling into a situation where the power performance of the auxiliary power supply 81 is exceeded can be reduced. In this way, even when an abnormality is detected in the main power supply 45, the operation of the rotating side motor 32 can continue appropriately. This effect is particularly significant when the power performance of the auxiliary power supply 81 is lower than that of the main power supply 45.

[0108] (3) In this embodiment, the main controller 60a of the rotating side controller 60 can determine the state of the power supply unit 80 based on the standby switch completion flag FLG. In this way, the main controller 60a can operate with the state of the power supply unit 80 in mind. However, a communication delay occurs in the communication between the main controller 60a and the power supply controller 88.

[0109] Here, as a comparative example, assume that the main controller 60a is configured to begin limiting the torque that can be output by the rotating-side motor 32 after the standby switch completion flag FLG is input. In this case, the switch from the connected state to the standby state in the power supply unit 80 is completed during the communication delay, and the main controller 60a does not begin limiting the torque that can be output by the rotating-side motor 32.

[0110] For example, such as Figure 7 As shown in (c), to be consistent with Figure 6 In the same manner as in (c), the main controller 60a determines that the state of the power supply unit 80 is not in standby state (“NON-BU” in the figure) until the standby switchover completion flag FLG is input.

[0111] On the other hand, such as Figure 7 As shown in (d), with Figure 6 Unlike (d), the maximum value Imax is calculated as the output limit value Ilim. Then, when the standby switchover completion flag FLG is input ("FLG Input" in the figure), the main controller 60a determines that the state of the power supply unit 80 is standby ("BU" in the figure).

[0112] That is, in the comparative example, after a voltage drop in the main power supply 45 is detected, the torque that can be output by the rotating-side motor 32 is not limited in the main controller 60a until the standby switching completion flag FLG is input. Specifically, in the case corresponding to ( Figure 6 During the "communication period" in (c), even if the power supply device 80 has completed the switch from the connected state to the standby state, the torque that can be output by the rotating side motor 32 is not limited.

[0113] On the other hand, such as Figure 6 As shown in (c) and (d), when a fault is detected in the main power supply 45, the main controller 60a according to this embodiment can begin limiting the torque that can be output by the rotating-side motor 32 earlier than the standby switch completion flag FLG is input. Therefore, in the configuration where the main controller 60a communicates with the power controller 88, the possibility of falling into a situation where the torque that can be output by the rotating-side motor 32 is unrestricted can be reduced in the standby state of the power supply device 80.

[0114] (4) According to this embodiment, when the start switch 46 is in the ON state, even if the main power supply 45 fails, power is continuously supplied to the control circuit 62a included in the main controller 60a. In this case, when the main power supply 45 fails, the control circuit 62a can start controlling the torque that can be output by the rotating side motor 32.

[0115] Other implementation methods

[0116] The above implementation method can be modified as follows. Furthermore, the other implementation methods described below can be combined with each other without any technical inconsistencies.

[0117] Diodes 86 and 87 can form an OR circuit inside the rotation-side controller 60 (i.e., steering control device 1). Even in this way, power with a higher supply voltage selected from the main power supply 45 or the auxiliary power supply 81 is supplied to the rotation-side controller 60.

[0118] The power performance of the auxiliary power supply 81 can be approximately equal to or higher than that of the main power supply 45. For example, the power capacity of the auxiliary power supply 81 can be approximately equal to or higher than that of the main power supply 45. In this case, for example, the power supply voltage V2 of the auxiliary power supply 81 can be set to be approximately equal to or higher than that of the main power supply 45.

[0119] Double-layer capacitors or secondary batteries can be used as auxiliary power supplies 81.

[0120] The power supply unit 80 can be operated to provide auxiliary power to each of the controllers 50, 60 in place of the main power supply 45 via a backup power supply, and additionally, to provide auxiliary power by boosting the power supplied by the main power supply 45.

[0121] Configurations associated with the standby switchover completion flag FLG can be eliminated. In this case, when a time has elapsed since a fault in the main power supply 45 was detected, assuming a switchover from the connected state to the standby state has been completed in the power supply unit 80, the main controller 60a of the rotating side controller 60 can determine that the power supply unit 80 is in the standby state. Furthermore, when a power supply voltage Vig1 equal to or higher than the threshold voltage Vth is detected, the main controller 60a can determine that the power supply unit 80 is in the standby state.

[0122] In controllers 50 and 60, the corresponding sub-controllers 50b and 60b can be eliminated, and single-system configurations of main controllers 50a and 60a can be provided respectively. In this case, for each of the main controllers 50a and 60a in the single-system configuration, it is sufficient for it to have the function of detecting the required power supply voltage.

[0123] In controllers 50 and 60, each of the sub-controllers 50b and 60b can be configured to be connected to the main power supply 45 via power supply unit 80. In this case, for each of the main controllers 50a and 60a in a single-system configuration, it is sufficient that it has the function of detecting the required power supply voltage.

[0124] When different values ​​are calculated as output limit values ​​Ilim, the limit controller 103 can have the function of gradually changing the output limit value Ilim relative to the different values. In this case, the influence of changes in the output limit value Ilim on vehicle behavior can be suppressed, and the comfort of vehicle occupants can be ensured.

[0125] The output limit value Ilim can have multiple values ​​depending on reasons other than a failure of the main power supply 45. For example, when multiple values ​​are candidate values ​​for the output limit value Ilim, it is sufficient for the limit controller 103 to have a function such as selecting the minimum value among the candidate values. That is, the limit controller 103 can be configured to ultimately calculate an output limit value Ilim that is equal to or less than the minimum value Imin when a failure occurs in the main power supply 45.

[0126] The power supply unit 80 may include a steering unit power supply unit that is only connected to the steering unit 4 including the steering side controller 50, and a rotation unit power supply unit that is only connected to the rotation unit 6 including the rotation side controller 60.

[0127] The steering control device 1 can be configured to include a controller by having either of the controllers 50 or 60 have the function of integrating the function of operating the steering-side motor 13 with the function of operating the rotation-side motor 32.

[0128] The rotating side motor 32 can be configured, for example, coaxially with the rack shaft 22, or connected to the pinion shaft of the rack and pinion mechanism constituting the rack shaft 22 via a worm and a worm wheel.

[0129] Each of the controllers 50 and 60 and the steering control device 1 including the controller may be constituted by processing circuitry comprising: 1) one or more processors operating according to a computer program (software); 2) one or more dedicated hardware circuits (e.g., application-specific integrated circuits (ASICs)) performing at least some of the various processes; or 3) combinations thereof. The processor includes a CPU and memory (e.g., RAM and ROM), and the memory stores program code or instructions configured to cause the CPU to perform processes. Memory (i.e., non-transitory computer-readable medium) includes any available medium that can be accessed by a general-purpose or special-purpose computer. The same applies to the power controller 88 and the power supply device 80 including the power controller 88.

[0130] The steering device 2 has been described as a linkageless structure in which the steering part 4 and the steering part 6 are always mechanically separated; however, the steering device 2 is not limited to this, and may, for example, have a structure in which the steering part 4 and the steering part 6 are mechanically separated by a clutch. Furthermore, the steering device 2 is not limited to a steering device of the steer-by-wire type, and may also be an electric steering device that applies motor torque to the steering shaft 11 or the rack shaft 22.

Claims

1. A steering control device (1) connected to a first power source mounted on a vehicle via a power supply device (80) and controlling a steering device mounted on the vehicle, the power supply device (80) including a second power source, the steering control device characterized in that it comprises: A controller includes a drive circuit (61a) that performs an action to supply power to a motor via a connection to at least one of a first power source and a second power source, and the controller is configured to control the operation of the motor by controlling the action of the drive circuit (61a), wherein: When the drive circuit (61a) is in a first state where power is supplied from the first power source, and an anomaly is detected in the first power source, the power supply device (80) switches the connection state to a second state where power is supplied from the second power source; and The controller is configured to perform an output limiting process after detecting an anomaly in the first power supply, compared to before the anomaly was detected. The output limiting process is a process that limits the torque that can be output by the motor. The output limiting process begins after the anomaly in the first power supply is detected and before the switching of the connection state to the second state in response to the detection of the anomaly is completed. The switching of the connection state is performed by the power supply device (80). The output limiting process is a process for limiting the torque output by the motor so that the torque does not exceed an output limit value.

2. The steering control device (1) according to claim 1, characterized in that, When the power performance of the second power supply is lower than that of the first power supply, the output limit value is less than the limit value of the power performance of the second power supply, and the power performance is limited by the power capacity or power voltage of the second power supply.

3. The steering control device (1) according to claim 1 or 2, characterized in that: The power supply device (80) includes a power controller (88) configured to switch the connection state in response to detecting an abnormality in the first power supply, such that the connection state changes to the second state. as well as The controller is configured to connect to the power controller (88) to communicate with the power controller (88) via a line, and is configured to obtain information from the power controller (88) via the line indicating that the switching of the connection state is complete when the connection state transitions to the second state.

4. The steering control device (1) according to any one of claims 1 to 2, characterized in that, The controller is configured to perform the output limiting process when the vehicle's power supply is in an on state that allows connection to the first power supply to enable operation of the vehicle.

5. The steering control device (1) according to claim 4, characterized in that: The controller includes a control circuit (62a) that performs processing related to the output limiting process; and The control circuit (62a) is configured to be connected to at least one of the first power source and the second power source, and regardless of the state of the first power source, the control circuit (62a) is always connected to at least one of the first power source and the second power source via a connection circuit included in the power supply device (80) when the power supply of the vehicle is in the on state.

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