JP6852580B2 - Steering control device - Google Patents

Description

The present invention relates to a steering control device.

Conventionally, there is known 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. Such a steering device is equipped with an electronic control device (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 driving and controlling the motor, and a plurality of drive circuits, and the microcomputers of each system control the drive circuit for a plurality of systems. Some motor coils are independently controlled. The microcomputer of each system supplies electric power to the coil of each system through the control of the drive circuit by generating the 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. If the ignition voltage supplied from the battery to the microcomputer of each system 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.

Japanese Unexamined Patent Publication No. 2011-195089

By the way, the transmission path of the ignition voltage from the battery to the microcomputer of each system is different due to factors such as different wiring lengths in each system and different influences of noise. Therefore, in a certain system of microcomputer, the assist control may be terminated because the ignition voltage is not within the preset range even though no abnormality has occurred in the power supply path from the battery to the microcomputer. There is. As a result, the assist amount output by the entire ECU becomes smaller as 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 continuously applying power to a steering mechanism by a plurality of systems of motors.

The steering control device capable of achieving the above object includes a plurality of control systems that apply power to the steering mechanism by controlling a motor having a plurality of coils by using the electric power of a power source mounted on the vehicle. Each of the plurality of control systems has a drive circuit for supplying electric power to the coils of each system and a steering control device having a control unit for controlling the drive circuit. A power supply status signal indicating whether or not it is within a preset range is generated, and each control unit has such that at least one of the power supply status signals is within a preset range of the voltage of the power supply. When is indicated, 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 status 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 of the power supply status 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. As a result, it is possible to continue to apply power to the steering mechanism in the plurality of systems.

In the steering control device, the motor has two coils, and the plurality of control systems are a first control system and two control systems having a second control system. The first control system includes a first drive circuit that supplies electric power to the coils of the first system and a first control unit that controls the first drive circuit, and the second control system. The system has a second drive circuit that supplies electric 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 the first control unit. A first power supply status signal indicating whether or not the voltage of the power supply is within a preset range is generated, and the second control unit determines whether or not the voltage of the power supply is within a preset range. A second power state signal indicating whether or not is generated is generated, and in the first control unit and the second control unit, at least one of the first power state signal and the second power state signal is said. When it 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 first control unit and the second control unit.

According to this configuration, if at least one of the first power supply status signal and the second power supply status signal indicates that the voltage of the power supply is within a preset range, the first control unit and The control of the motor by both of the second control units is continued. That is, unless both the first power state signal and the second power state signal indicate that the voltage of the power supply is not within the preset range, the first control unit and the second control unit The control of the motor can be continued. As a result, it is possible to continue to apply power to the steering mechanism in the plurality of systems.

In the steering control device, it is preferable that the plurality of control units share the power supply status signals by communicating with each other.
According to this configuration, the plurality of control units steer in a plurality of systems as long as at least one of the power supply status signals shared with each other indicates that the voltage of the power supply is within a preset range. Continue to give power to the mechanism.

In the steering control device, the voltage of the power supply is a voltage supplied from the power supply via the ignition switch, and the voltage supplied from the power supply via the ignition switch is preset in the plurality of control units. If it is equal to or more than the threshold value, the voltage of the power supply is assumed to be within the preset range, and if the voltage is less than the preset threshold value, the voltage of the power supply is not within the preset range. Is preferable.

According to this configuration, the plurality of control units assume that the voltage of the power supply is within the preset range if the voltage supplied via the ignition switch is equal to or higher than the preset threshold value. .. Therefore, 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. As a result, it is possible to continue to apply power to the steering mechanism in the plurality of systems.

According to the steering control device of the present invention, it is possible to continue to apply power to the steering mechanism by a plurality of motors.

FIG. 6 is a configuration diagram showing a schematic configuration of an embodiment of a steering device equipped with a steering control device. The block diagram which shows the schematic structure of the steering control device. The block diagram which shows the schematic structure of the 1st microcomputer and the 2nd microcomputer. The flowchart which shows the processing procedure of the change of the control mode of the assist control based on the 1st ignition state and the 2nd ignition state performed by the 1st microcomputer and the 2nd microcomputer. (A) to (c) are graphs showing the time change of the first ignition voltage and the second ignition voltage.

Hereinafter, an embodiment in which the steering control device is applied to the electric power steering device (EPS) will be described.
As shown in FIG. 1, EPS 1 is a steering mechanism 2 that steers the steering wheel 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 driver's steering operation. , 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 operated by the 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 of the column shaft 11a, and a pinion shaft 11c connected to the lower end of the intermediate shaft 11b. There is. The lower end of the pinion shaft 11c is connected to the rack shaft 12 via a rack and pinion mechanism 13. Therefore, in the steering mechanism 2, the rotational movement of the steering shaft 11 is converted into a reciprocating linear motion in the axial direction (left-right direction in FIG. 1) of the rack shaft 12 via the rack and pinion mechanism 13. The reciprocating linear motion is transmitted to the left and right steering wheels 15 via the tie rods 14 connected to both ends of the rack shaft 12, so that the steering angle of the steering wheels 15 changes and the traveling direction of the vehicle changes. Be changed.

The assist mechanism 3 includes a motor 20 having a rotating shaft 21 and a deceleration mechanism 22. The motor 20 applies an assist force (power) to the steering shaft 11. The rotating shaft 21 of the motor 20 is connected to the column shaft 11a via the reduction mechanism 22. The speed reduction mechanism 22 decelerates the rotation of the motor 20 and transmits the decelerated rotational force to the column shaft 11a. That is, the rotational force (torque) of the motor 20 is applied to the steering shaft 11 as an assist force, so that the driver's steering operation is assisted.

The ECU 30 controls the motor 20 based on the 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 41a and 41b are provided in the motor 20. Drive power is supplied to the ECU 30 from the battery Ba. The torque sensors 40a and 40b detect the steering torques τ1 and τ2 applied to the steering shaft 11 as the driver operates the steering wheel. The rotation angle sensors 41a and 41b detect the rotation angles θ1 and θ2 of the rotation shaft 21 of the motor 20. The ECU 30 sets a target motor torque (torque) to be applied to the steering mechanism 2 based on the output value of each sensor, and a 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. Further, the stator includes a plurality of systems of coils 24 wound around a stator core (not shown). The coil 24 has a coil 24a of the system A which is the first system and a coil 24b of the system B which is the second system. The coils 24a and 24b include star-connected U-phase, V-phase, and W-phase coils, respectively.

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

As a 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 a 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. Further, the first microcomputer 32a and the second microcomputer 32b have the same configuration. Further, the first current sensor 33a and the second current sensor 33b have the same configuration. Further, the first drive circuit 34a and the second drive circuit 34b have the same configuration. Here, detailed description of the same configuration will be omitted.

The first oscillator 31a generates a clock with a fundamental frequency. As the first oscillator 31a, for example, a crystal element or the like is adopted.
The first microcomputer 32a generates a synchronization signal (triangle wave) for adjusting the timing of the control operation of itself and the second microcomputer 32b based on the clock generated by the first oscillator 31a. The timing of the control operation is the timing at which the first microcomputer 32a and the second microcomputer 32b execute various operations, and is the time when the peak (vertex) and the valley (lowest point) in the triangular wave of the synchronization signal are reached. is there. Further, the first microcomputer 32a has a steering torque τ1 detected by the torque sensor 40a, a rotation angle θ1 detected by the rotation angle sensor 41a, and a current value detected by the first current sensor 33a at the timing of the control operation. A control signal Sm1 (PWM signal) is generated based on I1. The first current sensor 33a detects the current of each phase (U phase, V phase, W phase) flowing through the 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 is a direct current supplied from the battery Ba by turning on and off the switching elements constituting the first drive circuit 34a based on the control signal Sm1 generated by the first microcomputer 32a at the timing of the control operation. Converts power 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 timing of the control operation of itself and the first microcomputer 32a based on the clock generated by the second oscillator 31b. The second microcomputer 32b has a steering torque τ2 detected by the torque sensor 40b, a rotation angle θ2 detected by the rotation angle sensor 41b, and a current value I2 detected by the second current sensor 33b at the timing of the control operation. The control signal Sm2 (PWM signal) is generated based on the above. The second current sensor 33b detects the current of each phase flowing in the feeding path between the second drive circuit 34b and the coil 24b.

The second drive circuit 34b is a direct current supplied from the battery Ba by turning 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. Converts power into three-phase AC power. The second drive circuit 34b supplies three-phase AC power to the coil 24b.

In this way, the first microcomputer 32a and the second microcomputer 32b control the power supply 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 the diode D1 and the ignition switch IGSW which is a switch for starting the engine of the vehicle. The ignition switch IGSW is used between the battery Ba and the first microcomputer 32a and with 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). It is electrically connected to the second microcomputer 32b. Further, the ignition switch IGSW is used between the battery Ba and the first microcomputer 32a and the battery 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). The space between Ba and the second microcomputer 32b is electrically cut off.

Further, the first microcomputer 32a and the second microcomputer 32b are also connected to the battery Ba via the power relay Pr and the diode D2. Further, the first drive circuit 34a and the second drive circuit 34b are connected to the battery Ba via the power relay Pr. The power relay Pr is turned on and off by the ECU 30. As a result, when either the ignition switch IGSW or the power relay Pr is turned on, power is supplied from the battery Ba to the first microcomputer 32a and the second microcomputer 32b. When the power 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, and the first drive circuit are used from the battery Ba until the ECU 30 turns off the power relay Pr. Power is supplied to the 34a and the second drive circuit 34b.

Further, the first microcomputer 32a and the second microcomputer 32b set 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, for example, a voltage value between the ignition switch IGSW and the diode D1 in the 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 referred to as the first IG voltage Vig1, and the IG voltage Vig taken into the second microcomputer 32b is referred to as the second IG voltage Vig2. The first IG voltage Vig1 and the second IG voltage Vig2 differ in the transmission path transmitted to the first microcomputer 32a and the second microcomputer 32b. Therefore, the detected values may differ between the first IG voltage Vig1 and the second IG voltage Vig2 due to differences in the wiring length (length of the transmission path), the influence of noise, and the like.

The maximum value of the electric power supplied to the coil 24a of the system A is set to be the same as the maximum value of the electric power supplied to the coil 24b of the system B. The maximum value of the electric power supplied to the coil 24a and the coil 24b 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 32a 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. Further, the second microcomputer 32b 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.

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

The first current feedback control unit 51 has 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. The control signal Sm1 is calculated based on I1.

The second assist torque calculation unit 60 calculates the torque command value T2 *, which is the command value of the torque (assist amount) to be generated by the coil 24b of the system B, based on the steering torque τ2 detected by the torque sensor 40b. ..

The second current feedback control unit 61 has 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. The control signal Sm2 is calculated based on I2.

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 the preset range is, for example, whether or not the first IG voltage Vig1 is equal to or higher than the voltage threshold value V0. The upper limit of the first IG voltage Vig1 is, for example, the maximum voltage value of the battery Ba. Therefore, 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, and when the first IG voltage Vig1 is equal to or higher than the voltage threshold value V0, the IG state is in the ON state. The first IG state signal Ig1 indicating that is generated. On the other hand, when the first IG voltage Vig1 is less than the voltage threshold value V0, the first IG state determination unit 52 generates the first IG state signal Ig1 indicating that the IG state is in the off state. The voltage threshold value V0 is set to about the ignition voltage when it is considered to be 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 the preset range is, for example, whether or not the second IG voltage Vig2 is equal to or higher than the voltage threshold value V0. The upper limit of the second IG voltage Vig2 is, for example, the maximum voltage value of the battery Ba. Therefore, 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, and when the second IG voltage Vig2 is equal to or higher than the voltage threshold value V0, the IG state is in the ON state. A second IG state signal Ig2 indicating that is generated is generated. On the other hand, the second IG state determination unit 62 generates a second IG state signal Ig2 indicating that the IG state is in the off state when the second IG voltage Vig2 is less than the voltage threshold value V0.

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 Ig2 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 Ig1 captured 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 an off state, the first IG state determination unit 52 determines that the assist control cannot be continued and determines that the assist control is terminated. 1 Output to the assist torque calculation unit 50. Since it is determined by both the first IG state determination unit 52 and the second IG state determination unit 62 that the IG voltage Vig is not within the preset range, some abnormality has occurred in the power supply path between the battery Ba and the ECU 30. This is because it is considered to be a thing. On the other hand, the first IG state determination unit 52 assumes that the assist control can be continued when at least one of the first IG state signal Ig1 and the second IG state signal Ig2 indicates that the IG state is in the ON state. A determination result indicating that the assist control is to be continued is output to the first assist torque calculation unit 50. This is because if at least one of the first IG state signal Ig1 and the second IG state signal Ig2 indicates an 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 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.

Then, the first assist torque calculation unit 50 changes the control mode of the assist control based on the determination result indicating whether or not the assist control captured by the first IG state determination unit 52 can be continued. That is, when the first assist torque calculation unit 50 captures, for example, a determination result indicating that the assist control is terminated, the generation of the torque command value T1 * is terminated, and the determination result indicating that the assist control is continued is captured. , Continue to generate the torque command value T1 *.

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 second IG state determination unit 62 indicates that both the first IG state signal Ig1 and the second IG state signal Ig2 are in the off state, the assist control is terminated assuming that the assist control cannot be continued. The determination result indicating that the operation is to be performed is output to the second assist torque calculation unit 60. On the other hand, if at least one of the first IG state signal Ig1 and the second IG state signal Ig2 indicates an ON state, the second IG state determination unit 62 assumes that the assist control can be continued and continues the assist control. The indicated determination result is output to the second assist torque calculation unit 60.

Then, the second assist torque calculation unit 60 changes the control mode of the assist control based on the determination result indicating whether or not the assist control captured by the second IG state determination unit 62 can be continued. That is, when the second assist torque calculation unit 60 captures, for example, a determination result indicating that the assist control is terminated, the generation of the torque command value T2 * is terminated, and the determination result indicating that the assist control is continued is captured. , Continue to generate the torque command value T2 *.

Next, regarding the 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 will be described using.

As shown in the flowchart of FIG. 4, the first microcomputer 32a acquires the first IG voltage Vig1 (step S1) and generates the 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 the second IG state signal Ig2 (step S12).

The first microcomputer 32a notifies the second microcomputer 32b of the first IG state signal Ig1 by inter-microcomputer communication (step S3).
The second microcomputer 32b notifies the first microcomputer 32a of the second IG state signal Ig2 by inter-microcomputer communication (step S13). According to 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 with each other.

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 are in the off state (YES in step S4), the first microcomputer 32a terminates the assist control assuming that the assist control cannot be continued (YES). Step S5).

On the other hand, in the first microcomputer 32a, when 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. When it indicates that it is in a 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 an off state (step S14).
When both the first IG state signal Ig1 and the second IG state signal Ig2 are in the off state (YES in step S14), the second microcomputer 32b ends the assist control (step S15).

On the other hand, the second microcomputer 32b indicates that neither the first IG state signal Ig1 nor the second IG state signal Ig2 is 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. When it indicates that it is in a state (NO in step S14), the assist control is continued (step S16).

This completes the process.
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 it is sustainable.

In the example shown in FIG. 5A, the first IG voltage Vig1 is always equal to or higher than the voltage threshold value V0 regardless of the passage of time, whereas the second IG voltage Vig2 is temporarily lower than the voltage threshold value V0. This occurs when, for example, the power supply path from the battery Ba to the first microcomputer 32a is almost unaffected by noise, but the power supply path from the battery Ba to the second microcomputer 32b is greatly affected by 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 indication that the above is true. 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.

Further, as shown in FIG. 5B, the second IG voltage Vig2 is always equal to or higher than the voltage threshold value V0 regardless of the passage of time, whereas the first IG voltage Vig1 is always the voltage threshold value 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, and due to aged deterioration. It 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, the assist control is temporarily performed only in the system B.

On the other hand, in the present embodiment, the first IG state signal Ig1 and the second IG state signal Ig2 are determined by the first microcomputer-to-microcomputer communication unit 53 and the second microcomputer-to-microcomputer communication unit 63, and the first IG state determination unit 52 and the second IG state determination unit 52. It is shared with the part 62. Then, the first IG state determination unit 52 and the second IG state determination unit 62 determine whether or not 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. 5A, even when the second IG voltage Vig2 temporarily becomes less than the voltage threshold value V0, the second IG state determination unit 62 still receives the first IG state signal Ig1 and the second IG state. Assist control is continued based on the fact that neither of the signals Ig2 indicates an off state. In this way, 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 uses the first IG state signal Ig1. The assist control is continued based on the fact that neither the second IG state signal Ig2 nor the second IG state signal Ig2 indicates that the state is off. Therefore, the assist control in the two systems A and B can be continued.

Note that FIG. 5C shows a case where the first IG voltage Vig1 and the second IG voltage Vig2 become smaller with the passage of time even though the voltage threshold value V0 or more is initially set. In this case, in the first IG state determination unit 52 and the second IG state determination unit 62, since both the first IG state signal Ig1 and the second IG state signal Ig2 indicate an off state, it is assumed that a sufficient assist amount cannot be obtained. The assist control by the system A and the system B is terminated.

The present embodiment may be modified as follows. In addition, the following other embodiments can be combined with each other to the extent that they are technically consistent.
-In the present embodiment, the system is redundant with two systems, system A and system B, but may be redundant with three or more systems. When redundant to three or more systems, for example, when at least one of the IG state signals generated by each first IG state determination unit indicates an ON state, assist control in the three or more systems is continued.

-The rotation angle sensors 41a and 41b may be those using an MR sensor, those using a Hall sensor, or those using a resolver.
-In the present embodiment, the system A and the system B each generate an assist amount of half (50%) of the maximum assist amount of the motor 20, but the assist amount 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. 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 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 generated based on the battery voltage value which is the voltage value between the power supply relay Pr and the diode D2 in the wiring path between the battery Ba and the ECU 30.

In the present embodiment, the first IG state signal Ig1 and the second IG state are exchanged between the first microcomputer 32a and the second microcomputer 32b by the communication between the first microcomputer-to-microcomputer communication unit 53 and the second microcomputer-to-microcomputer communication unit 63. The signal Ig2 was shared, but it 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 the present invention is not limited to this. 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 based only on the second IG state signal Ig2. Judge whether or not. Then, the first IG state determination unit 52 and the second IG state determination unit 62 may share only the determination result of whether or not their assist control can be performed. Then, if any of the determination results 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, EPS1 that applies an assist force to the steering shaft 11 by the motor 20 is specifically shown, but the present invention is not limited to this. For example, it may be a steering device embodied in EPS 1 that applies an assist force to the rack shaft 12 by a motor 20 having a rotating shaft 21 arranged in parallel with the rack shaft 12. Further, the application is not limited to EPS1 that assists the steering operation by utilizing the rotational force of the motor 20, and may be applied 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 may be used as long as it is a steering device that applies power to the steering mechanism 2 by the motor 20.

1 ... EPS, 2 ... Steering mechanism, 3 ... Assist mechanism (powering mechanism), 10 ... Steering wheel, 11 ... Steering shaft, 11a ... Column shaft, 11b ... Intermediate shaft, 11c ... Pinion shaft, 12 ... Column shaft, 13 ... Rack and pinion mechanism, 14 ... Tie rod, 15 ... Steering wheel, 20 ... Motor, 21 ... Rotating shaft, 22 ... Reduction mechanism, 23 ... Rotor, 24, 24a, 24b ... Coil, 30 ... ECU, 31a ... First Oscillator, 31b ... Second oscillator, 32a ... First microcomputer (first control unit), 32b ... Second microcomputer (second control unit), 33a ... First current sensor, 33b ... Second current sensor, 34a ... 1st drive circuit, 34b ... 2nd drive circuit, 40a, 40b ... Torque sensor, 41a, 41b ... Rotation angle sensor, 50 ... 1st assist torque calculation unit, 51 ... 1st current feedback control unit, 52 ... 1 IG state determination unit, 53 ... 1st microcomputer communication unit, 60 ... 2nd assist torque calculation unit, 61 ... 2nd current feedback control unit, 62 ... 2nd IG state determination unit, 63 ... 2nd microcomputer communication unit, θ1 , Θ2 ... Rotation angle, τ1, τ2 ... Steering torque, Ba ... Battery, D1, D2 ... Diode, I1, I2 ... Current value, Ig1 ... 1st IG state signal, Ig2 ... 2nd 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 for applying power to the steering mechanism by controlling a motor having a plurality of coils by using the electric power of a power source mounted on the vehicle are provided, and the plurality of control systems are each system. In a steering control device having a drive circuit that supplies electric power to the coil and a control unit that controls the drive circuit.
Each of the control units generates a power supply status signal indicating whether or not the voltage of the power supply 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 supply status signals indicates that the voltage of the power supply is within a preset range. Steering control device. In the steering control device according to claim 1,
The motor has two systems of the coils, and the plurality of control systems are a first control system and two control systems having a second control system.
The first control system includes a first drive circuit that supplies electric power to the coils of the first system and a first control unit that controls the first drive circuit.
The second control system has a second drive circuit that supplies electric power to the coils of the second system and a second control unit that controls the second drive circuit.
The first control unit generates a first power supply state signal indicating whether or not the voltage of the power supply is within a preset range.
The second control unit generates a second power supply status signal indicating whether or not the voltage of the power supply is within a preset range.
The first control unit and the second control unit indicate that at least one of the first power supply status signal and the second power supply status signal is within a preset range of the voltage of the power supply. When indicated, a steering control device that continues to control the motor by both the first control unit and the second control unit. In the steering control device according to claim 1 or 2.
The plurality of control units are steering control devices that share the power supply status 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 supply is a voltage supplied from the power supply via the ignition switch.
When the voltage supplied via the ignition switch is equal to or higher than a preset threshold value, the plurality of control units assume that the voltage of the power supply is within a preset range, and the voltage is preset. A steering control device that assumes that the voltage of the power supply is not within a preset range when it is less than the threshold value.

Images