JP2019001216A - Steering control device - Google Patents

Abstract

To provide a steering control device which can continue to impart power to a steering mechanism by motors of plurality of system for a longer time.SOLUTION: A first assist torque calculation part 50 calculates a torque command value T1* on the basis of steering torque τ1. A first current feedback control part 51 calculates a control signal Sm1 on the basis of the torque command value T1*, a rotation angle θ1 and a current value I1. A first IG state determination part 52 creates a first IG state signal Ig1 indicating whether or not a first IG voltage Vig1 is within a preset range. The first IG state determination part 52 determines whether or not assist control can be continued on the basis of the first IG state signal Ig1 which is created by itself, and a second IG state signal Ig2 which is created by a second IG state determination part 62. When at least either of the first IG state signal Ig1 and the second IG state signal Ig2 indicates an on-state, the first IG state determination part 52 continues the assist control.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a steering control device.

  2. Description of the Related Art Conventionally, a steering device that assists a driver's steering operation by applying a driving force of a motor to a steering mechanism of a vehicle is known. Such a steering device is equipped with an electronic control unit (ECU) that controls the operation of the motor. By the way, as shown in Patent Document 1, the ECU is made redundant by providing a motor, a microcomputer for controlling driving of the motor, and a plurality of driving circuits, and the microcomputer of each system controls the driving circuit, so that a plurality of systems are provided. There are some which independently control the coils of the provided motor. The microcomputer of each system supplies electric power to the coils of each system through the control of the drive circuit by generating a motor control signal.

  In such an ECU, the microcomputers of each system are driven by being supplied with electric power from an in-vehicle battery. The microcomputer of each system determines whether or not the assist control can be continued based on whether or not the ignition voltage supplied from the battery via the ignition switch is within a preset range. When the ignition voltage supplied from the battery via the ignition switch is not within the preset range, it is considered that some abnormality has occurred in the power supply path from the battery to the microcomputer of each system. Assuming that the assist control in the microcomputer cannot be continued, the assist control in the microcomputer has been terminated.

JP 2011-195089 A

  By the way, the transmission path of the ignition voltage from the battery to the microcomputer of each system differs depending on factors such as different wiring lengths and different effects of noise in each system. For this reason, in a certain system of microcomputers, the assist control may end if the ignition voltage is not within a preset range even though there is no abnormality in the power supply path from the battery to the microcomputer. There is. As a result, the amount of assist output as a whole of the ECU is reduced by the amount that the assist control in the microcomputer of a certain system is stopped.

  An object of the present invention is to provide a steering control device capable of further continuing the application of power to a steering mechanism by a plurality of systems of motors.

  A steering control device that can achieve the above object includes a plurality of control systems that apply power to a steering mechanism by controlling a motor having a plurality of coils using the power of an on-vehicle power source. The plurality of control systems each include a drive circuit that supplies power to the coils of each system and a control unit that controls the drive circuit. The control unit generates a power state signal indicating whether or not it is within a preset range, and each of the control units has at least one of the power state signals within a preset range of the power source. In this case, the control of the motor by the plurality of control units is continued.

  According to this configuration, if at least one of the power supply state signals indicates that the voltage of the power supply is within a preset range, the control of the motor by the plurality of control units is continued. That is, as long as all the power supply state signals do not indicate that the voltage of the power supply is not within the preset range, the control of the motor by the plurality of control units can be continued. Thereby, the application of power to the steering mechanism in a plurality of systems can be further continued.

  In the above steering control device, the motor has two systems of the coils, and the plurality of control systems are two systems of control systems having a first control system and a second control system, The first control system includes a first drive circuit that supplies power to a coil of the first system and a first control unit that controls the first drive circuit, and the second control system. The system includes a second drive circuit that supplies power to the coils of the second system and a second control unit that controls the second drive circuit, and the first control unit includes: A first power state signal is generated to indicate whether the voltage of the power source is within a preset range, and the second control unit determines whether the voltage of the power source is within a preset range. A second power state signal indicating whether or not the first control unit and the second control signal are generated. The first control unit when at least one of the first power state signal and the second power state signal indicates that the voltage of the power source is within a preset range. It is preferable to continue the control of the motor by both the second control unit and the second control unit.

  According to this configuration, if at least one of the first power state signal and the second power state signal indicates that the voltage of the power source is within a preset range, the first control unit and Continue to control the motor in both of the second control units. That is, unless both the first power state signal and the second power state signal indicate that the voltage of the power source is not within a preset range, the first control unit and the second control unit Can continue to control the motor. Thereby, the application of power to the steering mechanism in a plurality of systems can be further continued.

In the steering control device described above, it is preferable that the plurality of control units share the power state signals by communicating with each other.
According to this configuration, the plurality of control units can perform steering in a plurality of systems if at least one of the power state signals shared with each other indicates that the voltage of the power source is within a preset range. Continue to apply power to the mechanism.

  In the above steering control device, the voltage of the power source is a voltage supplied from the power source via an ignition switch, and the plurality of control units are preset with the voltage supplied via the ignition switch. When the voltage is equal to or higher than the threshold value, the voltage of the power source is within a preset range. When the voltage is less than the preset threshold value, the voltage of the power source is not within the preset range. It is preferable that

  According to this configuration, when the voltage supplied via the ignition switch is equal to or higher than a preset threshold value, the plurality of control units are assumed to have the power supply voltage within a preset range. . For this reason, when at least one of the plurality of control units determines that the voltage supplied via the ignition switch is equal to or higher than a preset threshold value, the control of the motor by the plurality of control units is continued. Thereby, the application of power to the steering mechanism in a plurality of systems can be further continued.

  According to the steering control device of the present invention, the application of power to the steering mechanism by a plurality of systems of motors can be further continued.

The block diagram which shows the schematic structure about one Embodiment of the steering device which mounts a steering control apparatus. The block diagram which shows schematic structure of a steering control apparatus. The block diagram which shows schematic structure of a 1st microcomputer and a 2nd microcomputer. The flowchart which shows the process sequence of the change of the control aspect of assist control based on the 1st ignition state and the 2nd ignition state performed with a 1st microcomputer and a 2nd microcomputer. (A)-(c) is a graph which shows the time change of a 1st ignition voltage and a 2nd ignition voltage.

Hereinafter, an embodiment in which the steering control device is applied to an electric power steering device (EPS) will be described.
As shown in FIG. 1, the EPS 1 includes a steering mechanism 2 that steers the steered wheels 15 based on the operation of the steering wheel 10 of the driver (user), and an assist mechanism 3 (power applying mechanism) that assists the steering operation of the driver. And an ECU 30 (electronic control device) as a steering control device for controlling the assist mechanism 3.

  The steering mechanism 2 includes a steering wheel 10 that is operated by a driver and a steering shaft 11 that rotates integrally with the steering wheel 10. The steering shaft 11 has a column shaft 11a connected to the steering wheel 10, an intermediate shaft 11b connected to the lower end portion of the column shaft 11a, and a pinion shaft 11c connected to the lower end portion of the intermediate shaft 11b. Yes. A lower end portion of the pinion shaft 11 c is connected to the rack shaft 12 via a rack and pinion mechanism 13. Therefore, in the steering mechanism 2, the rotational motion of the steering shaft 11 is converted into a reciprocating linear motion in the axial direction of the rack shaft 12 (left and right direction in FIG. 1) via the rack and pinion mechanism 13. The reciprocating linear motion is transmitted to the left and right steered wheels 15 via the tie rods 14 respectively connected to both ends of the rack shaft 12, whereby the steered angle of the steered wheels 15 changes and the traveling direction of the vehicle changes. Be changed.

  The assist mechanism 3 includes a motor 20 having a rotation shaft 21 and a speed reduction mechanism 22. The motor 20 applies assist force (power) to the steering shaft 11. A rotation shaft 21 of the motor 20 is connected to the column shaft 11a via a speed reduction mechanism 22. The reduction mechanism 22 reduces the rotation of the motor 20 and transmits the reduced rotational force to the column shaft 11a. That is, the turning force (torque) of the motor 20 is applied to the steering shaft 11 as an assist force, thereby assisting the driver's steering operation.

  The ECU 30 controls the motor 20 based on detection results of various sensors provided in the vehicle. As various sensors, for example, torque sensors 40a and 40b and rotation angle sensors 41a and 41b are provided. The torque sensors 40a and 40b are provided on the column shaft 11a. Further, the rotation angle sensors 41 a and 41 b are provided in the motor 20. The ECU 30 is supplied with driving power from the battery Ba. The torque sensors 40a and 40b detect steering torques τ1 and τ2 applied to the steering shaft 11 in accordance with the driver's steering operation. The rotation angle sensors 41 a and 41 b detect the rotation angles θ1 and θ2 of the rotation shaft 21 of the motor 20. The ECU 30 sets the target motor torque (torque) to be applied to the steering mechanism 2 based on the output value of each sensor, and the current supplied to the motor 20 so that the actual motor torque becomes the target motor torque. To control.

Next, the motor 20 will be described in detail.
As shown in FIG. 2, the motor 20 includes a stator and a rotor 23 (not shown). A plurality of permanent magnets are provided inside the rotor 23. The stator includes a plurality of coils 24 wound around a stator core (not shown). The coil 24 includes a coil 24a of the system A that is the first system and a coil 24b of the system B that is the second system. The coils 24a and 24b include U-phase, V-phase, and W-phase coils that are star-connected, respectively.

Next, the ECU 30 will be described.
As shown in FIG. 2, the ECU 30 includes a part of the system A that controls the power supplied to the coil 24 a and a part of the system B that controls the power supplied to the coil 24 b.

  As part of the system A of the ECU 30, a first oscillator 31a, a first microcomputer 32a (first control unit), a first current sensor 33a, and a first drive circuit 34a are provided. Further, as part of the system B of the ECU 30, a second oscillator 31b, a second microcomputer 32b (second control unit), a second current sensor 33b, and a second drive circuit 34b are provided. The first oscillator 31a and the second oscillator 31b have the same configuration. The first microcomputer 32a and the second microcomputer 32b have the same configuration. The first current sensor 33a and the second current sensor 33b have the same configuration. The first drive circuit 34a and the second drive circuit 34b have the same configuration. Here, detailed description of the same configuration is omitted.

The first oscillator 31a generates a clock having a fundamental frequency. As the first oscillator 31a, for example, a crystal element or the like is employed.
The first microcomputer 32a generates a synchronization signal (triangular wave) for adjusting the control operation timing of itself and the second microcomputer 32b based on the clock generated by the first oscillator 31a. Note that the timing of the control operation is the timing at which the first microcomputer 32a and the second microcomputer 32b execute various calculations, and at the time when they become peaks (vertices) and valleys (bottom points) in the triangular wave of the synchronization signal. is there. The first microcomputer 32a also controls the steering torque τ1 detected by the torque sensor 40a, the rotation angle θ1 detected by the rotation angle sensor 41a, and the current value detected by the first current sensor 33a at the timing of the control operation. Based on I1, a control signal Sm1 (PWM signal) is generated. The first current sensor 33a detects the current of each phase (U-phase, V-phase, W-phase) flowing through the power feeding path between the first drive circuit 34a and the coil 24a.

  The first drive circuit 34a is a three-phase (U phase, V phase, W phase) drive circuit. The first drive circuit 34a turns on and off the switching elements constituting the first drive circuit 34a on the basis of the control signal Sm1 generated by the first microcomputer 32a at the timing of the control operation, so that the direct current supplied from the battery Ba Power is converted into three-phase AC power. The first drive circuit 34a supplies three-phase AC power to the coil 24a.

  The second microcomputer 32b generates a synchronization signal for adjusting the control operation timing of itself and the first microcomputer 32a based on the clock generated by the second oscillator 31b. The second microcomputer 32b controls the steering torque τ2 detected by the torque sensor 40b, the rotation angle θ2 detected by the rotation angle sensor 41b, and the current value I2 detected by the second current sensor 33b at the timing of the control operation. Based on the above, the control signal Sm2 (PWM signal) is generated. The second current sensor 33b detects the current of each phase that flows through the power feeding path between the second drive circuit 34b and the coil 24b.

  The second drive circuit 34b turns on and off the switching elements constituting the second drive circuit 34b based on the control signal Sm2 generated by the second microcomputer 32b at the timing of the control operation, so that the direct current supplied from the battery Ba Power is converted into three-phase AC power. The second drive circuit 34b supplies three-phase AC power to the coil 24b.

  As described above, the first microcomputer 32a and the second microcomputer 32b control power feeding to the coil 24a of the system A and the coil 24b of the system B through the control of the first drive circuit 34a and the second drive circuit 34b.

  The first microcomputer 32a and the second microcomputer 32b are connected to the battery Ba via a diode D1 and an ignition switch IGSW that is a switch for starting the engine of the vehicle. The ignition switch IGSW is connected between the battery Ba and the first microcomputer 32a and the battery Ba when the ignition is turned on by an input from the outside of the vehicle (for example, an on operation by a key and a button performed by the driver). The second microcomputer 32b is electrically connected. In addition, the ignition switch IGSW is connected between the battery Ba and the first microcomputer 32a when the ignition is turned off by an input from the outside of the vehicle (for example, an off operation by a key and a button performed by the driver), and the battery Electrical isolation is performed between Ba and the second microcomputer 32b.

  The first microcomputer 32a and the second microcomputer 32b are also connected to the battery Ba via a power relay Pr and a diode D2. The first drive circuit 34a and the second drive circuit 34b are connected to the battery Ba via the power supply relay Pr. The power relay Pr is turned on and off by the ECU 30. Thus, when one of the ignition switch IGSW and the power supply relay Pr is turned on, power is supplied from the battery Ba to the first microcomputer 32a and the second microcomputer 32b. Further, when the power supply relay Pr is turned on, power is supplied from the battery Ba to the first microcomputer 32a, the second microcomputer 32b, the first drive circuit 34a, and the second drive circuit 34b. Further, even when the ignition switch IGSW is turned off by an input from the outside of the vehicle, the first microcomputer 32a, the second microcomputer 32b, the first drive circuit from the battery Ba until the ECU 30 turns off the power relay Pr. Electric power is supplied to 34a and the second drive circuit 34b.

  Further, the first microcomputer 32a and the second microcomputer 32b use the IG voltage Vig (ignition voltage) in order to detect whether or not a predetermined voltage is supplied from the battery Ba when the ignition switch IGSW is turned on. take in. The IG voltage Vig is a voltage value between the ignition switch IGSW and the diode D1, for example, in a wiring path between the battery Ba and the ECU 30. The IG voltage Vig is input to the first microcomputer 32a and the second microcomputer 32b in a state of being divided by a voltage dividing circuit or the like. Further, the IG voltage Vig taken into the first microcomputer 32a is a first IG voltage Vig1, and the IG voltage Vig taken into the second microcomputer 32b is a second IG voltage Vig2. The first IG voltage Vig1 and the second IG voltage Vig2 have different transmission paths that are transmitted to the first microcomputer 32a and the second microcomputer 32b. For this reason, the first IG voltage Vig1 and the second IG voltage Vig2 may have different detected values due to different wiring lengths (transmission path lengths), different noise influences, and the like.

  The maximum value of power supplied to the coil 24a of the system A is set to be the same as the maximum value of power supplied to the coil 24b of the system B. The maximum value of the electric power supplied to the coils 24 a and 24 b is a value corresponding to half of the maximum torque (assist amount) that can be output by the motor 20.

Next, the first microcomputer 32a and the second microcomputer 32b will be described in detail.
As shown in FIG. 3, the first microcomputer 32 a includes a first assist torque calculation unit 50, a first current feedback control unit 51, a first IG state determination unit 52, and a first inter-microcomputer communication unit 53. The second microcomputer 32 b includes a second assist torque calculation unit 60, a second current feedback control unit 61, a second IG state determination unit 62, and a second inter-microcomputer communication unit 63.

  Based on the steering torque τ1 detected by the torque sensor 40a, the first assist torque calculator 50 calculates a torque command value T1 * that is a command value of torque (assist amount) to be generated by the coil 24a of the system A. .

  The first current feedback control unit 51 includes a torque command value T1 * calculated by the first assist torque calculation unit 50, a rotation angle θ1 detected by the rotation angle sensor 41a, and a current value detected by the first current sensor 33a. Based on I1, the control signal Sm1 is calculated.

  Based on the steering torque τ2 detected by the torque sensor 40b, the second assist torque calculator 60 calculates a torque command value T2 * that is a command value of torque (assist amount) to be generated by the coil 24b of the system B. .

  The second current feedback control unit 61 includes a torque command value T2 * calculated by the second assist torque calculation unit 60, a rotation angle θ2 detected by the rotation angle sensor 41b, and a current value detected by the second current sensor 33b. Based on I2, the control signal Sm2 is calculated.

  Further, the first IG state determination unit 52 generates a first IG state signal Ig1 indicating whether or not the first IG voltage Vig1 is within a preset range (IG state). Whether or not it is within a preset range is, for example, whether or not the first IG voltage Vig1 is equal to or higher than the voltage threshold V0. The upper limit value of the first IG voltage Vig1 is, for example, the maximum voltage value of the battery Ba. For this reason, for example, the first IG state determination unit 52 determines whether or not the first IG voltage Vig1 is equal to or higher than the voltage threshold value V0. When the first IG voltage Vig1 is equal to or higher than the voltage threshold value V0, the IG state is on. A first IG state signal Ig1 indicating this is generated. On the other hand, when the first IG voltage Vig1 is less than the voltage threshold V0, the first IG state determination unit 52 generates a first IG state signal Ig1 indicating that the IG state is the off state. The voltage threshold V0 is set to about the ignition voltage when it is considered normal.

  Further, the second IG state determination unit 62 generates a second IG state signal Ig2 indicating whether or not the second IG voltage Vig2 is within a preset range. Whether or not it is within a preset range is, for example, whether or not the second IG voltage Vig2 is equal to or higher than the voltage threshold V0. The upper limit value of second IG voltage Vig2 is, for example, the maximum voltage value of battery Ba. For this reason, for example, the second IG state determination unit 62 determines whether or not the second IG voltage Vig2 is equal to or higher than the voltage threshold value V0. When the second IG voltage Vig2 is equal to or higher than the voltage threshold value V0, the IG state is on. A second IG state signal Ig2 indicating this is generated. In contrast, when the second IG voltage Vig2 is less than the voltage threshold V0, the second IG state determination unit 62 generates a second IG state signal Ig2 indicating that the IG state is the off state.

  The first inter-microcomputer communication unit 53 transmits the first IG state signal Ig1 generated by the first IG state determination unit 52 to the second inter-microcomputer communication unit 63. Further, the second inter-microcomputer communication unit 63 transmits the second IG state signal Ig2 generated by the second IG state determination unit 62 to the first inter-microcomputer communication unit 53. The first inter-microcomputer communication unit 53 outputs the second IG state signal Ig <b> 2 captured from the second inter-microcomputer communication unit 63 to the first IG state determination unit 52. Further, the second inter-microcomputer communication unit 63 outputs the first IG state signal Ig <b> 1 taken from the first inter-microcomputer communication unit 53 to the second IG state determination unit 62.

  The first IG state determination unit 52 determines whether or not the assist control can be continued based on the first IG state signal Ig1 generated by itself and the second IG state signal Ig2 generated by the second IG state determination unit 62. Specifically, the first IG state determination unit 52 determines whether or not both the first IG state signal Ig1 and the second IG state signal Ig2 indicate an off state. When both the first IG state signal Ig1 and the second IG state signal Ig2 indicate the off state, the first IG state determination unit 52 determines that the assist control cannot be continued, and determines the determination result indicating that the assist control is ended. 1 is output to the assist torque calculator 50. The first IG state determination unit 52 and the second IG state determination unit 62 have determined that the IG voltage Vig is not in the preset range, so that some abnormality has occurred in the power supply path between the battery Ba and the ECU 30. Because it is considered to be a thing. On the other hand, when at least one of the first IG state signal Ig1 and the second IG state signal Ig2 indicates that the IG state is on, the first IG state determination unit 52 can continue the assist control. A determination result indicating that the assist control is continued is output to the first assist torque calculator 50. This is because if at least one of the first IG state signal Ig1 and the second IG state signal Ig2 indicates the on state, it is considered that no abnormality has occurred in the power supply path between the battery Ba and the ECU 30. Even if either one of the first IG state signal Ig1 or the second IG state signal Ig2 indicates an off state, the detected first IG voltage Vig1 and second IG voltage Vig2 vary.

  And the 1st assist torque calculating part 50 changes the control aspect of assist control based on the determination result which shows whether the assist control taken in by the 1st IG state determination part 52 can be continued. That is, for example, when the first assist torque calculation unit 50 captures a determination result indicating that the assist control is to be terminated, the first assist torque calculation unit 50 terminates generation of the torque command value T1 * and captures a determination result that indicates that the assist control is to be continued. The generation of the torque command value T1 * is continued.

  The second IG state determination unit 62 determines whether or not the assist control can be continued based on the second IG state signal Ig2 generated by itself and the first IG state signal Ig1 generated by the first IG state determination unit 52. Specifically, when the first IG state signal Ig1 and the second IG state signal Ig2 indicate that both are in the off state, the second IG state determination unit 62 ends the assist control as a case where the assist control cannot be continued. A determination result indicating that it is to be output is output to the second assist torque calculator 60. On the other hand, the second IG state determination unit 62 continues the assist control by assuming that the assist control can be continued if at least one of the first IG state signal Ig1 and the second IG state signal Ig2 indicates the on state. The determination result shown is output to the second assist torque calculator 60.

  And the 2nd assist torque calculating part 60 changes the control aspect of assist control based on the determination result which shows whether the assist control taken in by the 2nd IG state determination part 62 can be continued. That is, when the second assist torque calculation unit 60 captures a determination result indicating that the assist control is terminated, for example, the second assist torque calculation unit 60 terminates generation of the torque command value T2 * and captures a determination result that indicates that the assist control is continued. The generation of the torque command value T2 * is continued.

  Next, with respect to a method of changing the control mode of the assist control based on the first IG state signal Ig1 and the second IG state signal Ig2 performed by the first microcomputer 32a and the second microcomputer 32b, the processing procedure is shown in the flowchart of FIG. It explains using.

As shown in the flowchart of FIG. 4, the first microcomputer 32a acquires the first IG voltage Vig1 (step S1) and generates a first IG state signal Ig1 (step S2).
On the other hand, the second microcomputer 32b acquires the second IG voltage Vig2 (step S11) and generates a second IG state signal Ig2 (step S12).

The first microcomputer 32a notifies the second microcomputer 32b of the first IG state signal Ig1 through communication between microcomputers (step S3).
The second microcomputer 32b notifies the first microcomputer 32a of the second IG state signal Ig2 through communication between microcomputers (step S13). With these notifications, the first microcomputer 32a and the second microcomputer 32b share the first IG state signal Ig1 and the second IG state signal Ig2.

Next, the first microcomputer 32a determines whether or not both the first IG state signal Ig1 and the second IG state signal Ig2 indicate an off state (step S4).
When both the first IG state signal Ig1 and the second IG state signal Ig2 indicate that they are in the off state (YES in step S4), the first microcomputer 32a ends the assist control assuming that the assist control cannot be continued ( Step S5).

  In contrast, the first microcomputer 32a indicates that both the first IG state signal Ig1 and the second IG state signal Ig2 are not in the off state, that is, at least one of the first IG state signal Ig1 and the second IG state signal Ig2 is on. If it is an indication of the state (NO in step S4), the assist control is continued (step S6).

Further, the second microcomputer 32b determines whether or not both the first IG state signal Ig1 and the second IG state signal Ig2 indicate the off state (step S14).
If both the first IG state signal Ig1 and the second IG state signal Ig2 are off (YES in step S14), the second microcomputer 32b ends the assist control (step S15).

  On the other hand, the second microcomputer 32b indicates that both the first IG state signal Ig1 and the second IG state signal Ig2 are not off, that is, at least one of the first IG state signal Ig1 and the second IG state signal Ig2 is on. If it is an indication of the state (NO in step S14), the assist control is continued (step S16).

The process ends here.
The operation and effect of this embodiment will be described.
First, as a comparative example, a case where the first IG state signal Ig1 and the second IG state signal Ig2 are not shared between the first IG state determination unit 52 and the second IG state determination unit 62 will be described. In this case, the first IG state determination unit 52 determines whether the assist control can be continued based only on the first IG state signal Ig1, and the second IG state determination unit 62 performs the assist control based only on the second IG state signal Ig2. Determine if continuation is possible.

  In the example shown in FIG. 5A, the first IG voltage Vig1 is always equal to or higher than the voltage threshold V0 regardless of the passage of time, whereas the second IG voltage Vig2 is temporarily lower than the voltage threshold V0. This occurs, for example, when the power supply path from the battery Ba to the first microcomputer 32a has almost no influence of noise, but the power supply path from the battery Ba to the second microcomputer 32b has a large influence of noise. Since the first IG state determination unit 52 indicates that the first IG state signal Ig1 is in the on state, the assist control is continued, but the second IG state determination unit 62 temporarily turns off the second IG state signal Ig2. The assist control is temporarily terminated based on the fact that it is indicated to be. Even in such a case, although the assist control can be continued using the system A and the system B, the assist control is performed only for the system A.

  As shown in FIG. 5B, the second IG voltage Vig2 is always equal to or higher than the voltage threshold V0 regardless of the passage of time, whereas the first IG voltage Vig1 is always equal to the voltage threshold regardless of the passage of time. It may be less than V0. This is because, for example, the length (wiring length) of the power supply path from the battery Ba to the first microcomputer 32a is longer than the length of the power supply path from the battery Ba to the second microcomputer 32b. Occurs when the voltage drop in both power supply paths becomes large. However, even in this case, although power is supplied to the system A and the system B, only the system B is temporarily controlled.

  On the other hand, in the present embodiment, the first IG state determination unit 52 and the second IG state determination are performed by the first inter-microcomputer communication unit 53 and the second inter-microcomputer communication unit 63 to determine the first IG state signal Ig1 and the second IG state signal Ig2, respectively. Shared with the unit 62. The first IG state determination unit 52 and the second IG state determination unit 62 determine whether the assist control can be continued based on both the first IG state signal Ig1 and the second IG state signal Ig2.

  Therefore, as shown in FIG. 5 (a), even if the second IG voltage Vig2 is temporarily less than the voltage threshold V0, the second IG state determination unit 62 determines that the first IG state signal Ig1 and the second IG state The assist control is continued based on the fact that both of the signals Ig2 do not indicate the off state. Thus, even if either the first IG state signal Ig1 or the second IG state signal Ig2 is temporarily turned off, both the first IG state signal Ig1 and the second IG state signal Ig2 indicate the off state. Until then, the assist control in the two systems of system A and system B can be continued.

  Further, as shown in FIG. 5B, even when the first IG voltage Vig1 is always less than the voltage threshold value V0 regardless of the passage of time, the first IG state determination unit 52 performs the first IG state signal Ig1. The assist control is continued based on the fact that both the second IG state signal Ig2 and the second IG state signal Ig2 do not indicate that they are off. For this reason, the assist control in the two systems of the system A and the system B can be continued.

  FIG. 5 (c) shows a case where the first IG voltage Vig1 and the second IG voltage Vig2 are reduced with the passage of time although the voltage is initially equal to or higher than the voltage threshold V0. In this case, the first IG state determination unit 52 and the second IG state determination unit 62 indicate that both the first IG state signal Ig1 and the second IG state signal Ig2 indicate an off state, and therefore, a sufficient assist amount cannot be obtained. The assist control by the system A and the system B is finished.

In addition, you may change this embodiment as follows. Further, the following other embodiments can be combined with each other within a technically consistent range.
In the present embodiment, redundancy is made to two systems of system A and system B, but redundancy may be made to three or more systems. In the case of redundancy in three or more systems, for example, when at least one of each IG state signal generated by each first IG state determination unit indicates an ON state, assist control in three or more systems is continued.

The rotation angle sensors 41a and 41b may be those using MR sensors, those using Hall sensors, or those using resolvers.
In the present embodiment, the system A and the system B each generate an assist amount that is half (50%) of the maximum assist amount of the motor 20, but the present invention is not limited to this. That is, the maximum assist amount that can be generated in the system A may be different from the maximum assist amount that can be generated in the system B. Note that the sum of the maximum torque that can be generated in the system A and the maximum torque that can be generated in the system B is set within 100% in total.

  In the present embodiment, the first IG state signal Ig1 and the second IG state signal Ig2 are generated based on the first IG voltage Vig1 and the second IG voltage Vig2, but this is not restrictive. For example, the first IG state signal Ig1 and the second IG state signal Ig2 may be generated based on a battery voltage value that is a voltage value between the power supply relay Pr and the diode D2 in the wiring path of the battery Ba and the ECU 30.

  In the present embodiment, the first IG state signal Ig1 and the second IG state are communicated between the first microcomputer 32a and the second microcomputer 32b by communication between the first microcomputer communication section 53 and the second microcomputer communication section 63. Although the signal Ig2 is shared, the present invention is not limited to this. For example, the first IG state signal Ig1 and the second IG state signal Ig2 may be shared by an in-vehicle network or the like.

  In the present embodiment, the first IG state signal Ig1 and the second IG state signal Ig2 are shared between the first IG state determination unit 52 and the second IG state determination unit 62, but this is not limitative. For example, the first IG state determination unit 52 determines whether or not the assist control can be continued based only on the first IG state signal Ig1, and the second IG state determination unit 62 can perform the assist control only based on the second IG state signal Ig2. Determine whether or not. And the 1st IG state determination part 52 and the 2nd IG state determination part 62 may share only the determination result of whether those assist control is possible. If any determination result indicates that the assist control can be continued, the first assist torque calculation unit 50 and the second assist torque calculation unit 60 continue the assist control.

  In the present embodiment, the EPS 20 that applies the assisting force to the steering shaft 11 by the motor 20 is specifically shown, but the invention is not limited thereto. For example, a steering device embodied in EPS 1 that applies assist force to the rack shaft 12 by a motor 20 having a rotating shaft 21 arranged in parallel to the rack shaft 12 may be used. Moreover, you may apply not only to EPS1 which assists steering operation using the rotational force of the motor 20, but to steer-by-wire (SBW). It can also be embodied as a rear wheel steering device or a four wheel steering device (4WS). That is, any steering device that applies power to the steering mechanism 2 by the motor 20 may be used.

  DESCRIPTION OF SYMBOLS 1 ... EPS, 2 ... Steering mechanism, 3 ... Assist mechanism (power supply mechanism), 10 ... Steering wheel, 11 ... Steering shaft, 11a ... Column shaft, 11b ... Intermediate shaft, 11c ... Pinion shaft, 12 ... Column shaft, DESCRIPTION OF SYMBOLS 13 ... Rack and pinion mechanism, 14 ... Tie rod, 15 ... Steering wheel, 20 ... Motor, 21 ... Rotating shaft, 22 ... Deceleration mechanism, 23 ... Rotor, 24, 24a, 24b ... Coil, 30 ... ECU, 31a ... 1st Oscillator, 31b ... second oscillator, 32a ... first microcomputer (first controller), 32b ... second microcomputer (second controller), 33a ... first current sensor, 33b ... second current sensor, 34a ... first drive circuit, 34b ... second drive circuit, 40a, 40b ... torque sensor, 41a, 41b ... rotation angle sensor, 50 ... DESCRIPTION OF SYMBOLS 1 assist torque calculating part, 51 ... 1st electric current feedback control part, 52 ... 1st IG state determination part, 53 ... 1st microcomputer communication part, 60 ... 2nd assist torque calculating part, 61 ... 2nd electric current feedback control part, 62 ... 2nd IG state determination part, 63 ... 2nd communication part between microcomputers, (theta) 1, (theta) 2 ... rotation angle, (tau) 1, (tau) 2 ... steering torque, Ba ... battery, D1, D2 ... diode, I1, I2 ... current value, Ig1 ... First IG state signal, Ig2 ... Second IG state signal, IGSW ... Ignition switch, Pr ... Power relay, Sm1, Sm2 ... Control signal, T1 *, T2 * ... Torque command value, Vig ... IG voltage (ignition voltage), Vig1 ... 1st IG voltage, Vig2 ... 2nd IG voltage.

Claims (4)

A plurality of control systems that apply power to the steering mechanism by controlling a motor having a plurality of coils using the power of the power source mounted on the vehicle, and each of the plurality of control systems includes In a steering control device having a drive circuit for supplying power to the coil and a control unit for controlling the drive circuit,
Each of the control units generates a power status signal indicating whether or not the voltage of the power source is within a preset range,
Each of the control units continues to control the motor by the plurality of control units when at least one of the power status signals indicates that the voltage of the power source is within a preset range. Steering control device. The steering control device according to claim 1, wherein
The motor has two systems of the coils, and the plurality of control systems are two control systems having a first control system and a second control system,
The first control system includes a first drive circuit that supplies power to a coil of the first system and a first control unit that controls the first drive circuit,
The second control system includes a second drive circuit that supplies power to a coil of the second system and a second control unit that controls the second drive circuit,
The first control unit generates a first power state signal indicating whether or not the voltage of the power source is within a preset range;
The second control unit generates a second power state signal indicating whether the voltage of the power source is within a preset range;
The first control unit and the second control unit may determine that at least one of the first power supply state signal and the second power supply state signal is within a preset range of the power supply voltage. A steering control device that continues control of the motor in both the first control unit and the second control unit when shown. The steering control device according to claim 1 or 2,
The plurality of control units is a steering control device that shares the power state signals by communicating with each other. In the steering control device according to any one of claims 1 to 3,
The voltage of the power source is a voltage supplied from the power source via an ignition switch,
When the voltage supplied via the ignition switch is equal to or higher than a preset threshold, the plurality of control units are assumed to have a voltage of the power source within a preset range, and the voltage is preset. A steering control device that assumes that the voltage of the power source is not within a preset range when the threshold is less than the set threshold.