JP2011148498A - Control method and control device of electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control method and a control device of an electric power steering device for improving safety and reliability, by preventing erroneous operation of a plurality of control part cooperative operations, even when being different in an operation clock frequency of a system constituted of a plurality of control parts having a main control part (a CPU or an MCU) and a subordinate control part (a CPU or an MCU). <P>SOLUTION: The electric power steering device includes: an electric current command value arithmetic operation part for arithmetically operating an electric current command value based on steering torque generated in a steering shaft and a vehicle speed signal; and a driving control part for controlling driving of a motor for imparting steering assisting force to a steering mechanism based on an electric current value of the motor and the electric current command value. The electric current command value arithmetic operation part and the driving control part are constituted of the main control part and the subordinate control part which can communicate with each other. In the control method of the electric power steering device, the main control part and the subordinate control part are synchronized when a specific condition is satisfied. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method and apparatus for controlling an electric power steering apparatus that applies a steering assist force by a motor to a steering system of a vehicle. Control method and control device for electric power steering apparatus which prevents malfunction of cooperative operation of multiple CPUs by synchronizing during initial diagnosis even if system operating clock frequency is different About.

  An electric power steering apparatus that assists and biases a steering mechanism of a vehicle with the rotational force of a motor is provided with an auxiliary load on a steering shaft or a rack shaft by a transmission mechanism such as a gear or a belt via a speed reducer. Has come to be energized.

  Such a conventional electric power steering apparatus performs feedback control of motor current in order to accurately generate assist torque (steering assist torque). In this feedback control, the motor applied voltage is adjusted so that the difference between the current command value and the detected motor current value becomes small. The motor applied voltage is generally adjusted by adjusting the duty ratio of pulse width modulation (PWM) control.

  Here, a general configuration of the electric power steering apparatus will be described with reference to FIG. The column shaft 2 of the steering handle 1 is connected to a tie rod 6 of a steering wheel via a reduction gear 3, universal joints 4A and 4B, and a pinion rack mechanism 5. The column shaft 2 is provided with a torque sensor 10 that detects the steering torque of the steering handle 1, and a motor 20 that assists the steering force of the steering handle 1 is connected to the column shaft 2 via the reduction gear 3. Has been. The control unit 30 that controls the electric power steering apparatus is supplied with electric power from the battery 14 and is also supplied with an ignition signal from the ignition key 11. The control unit 30 detects the steering torque T detected by the torque sensor 10 and the vehicle speed. An assist command steering assist command value I is calculated based on the vehicle speed V detected by the sensor 12, and a current supplied to the motor 20 is controlled based on the calculated steering assist command value I.

  The control unit 30 is mainly composed of a CPU, and the functions and operations of the control unit 30 will be described with reference to FIG.

  The steering torque T detected and input by the torque sensor 10 is phase-compensated by the phase compensator 31, and the phase-compensated steering torque TA is input to the steering assist command value calculator 32 and detected by the vehicle speed sensor 12. The vehicle speed V is also input to the steering assist command value calculator 32. The steering assist command value calculator 32 determines a steering assist command value I that is a control target value of the current supplied to the motor 20 based on the input steering torque TA and vehicle speed V. The steering assist command value I is input to the subtractor 30A, and is also input to the feedforward differential compensator 34 for increasing the response speed. The deviation (Ii) of the subtractor 30A is input to the proportional calculator 35. At the same time, it is input to an integration calculator 36 for improving the characteristics of the feedback system, and each output is input to an adder 30B. The output of the differential compensator 34 is also added to the adder 30B, and the current control value E, which is the addition result of the adder 30B, is input to the motor drive circuit 37 as a motor drive signal. The motor current value i of the motor 20 is detected by the motor current detection circuit 38, and the motor current detection value i is input to the subtractor 30A and fed back. Electric power is supplied to the motor drive circuit 37 from the battery 14 via the relay contact 13.

  Next, a configuration example of the motor drive circuit 37 will be described with reference to FIG. 11. The motor drive circuit 37 converts the PWM signal and the current direction signal into a PWM signal and a current direction signal based on the current control value E from the adder 30B. An FET gate drive circuit 372 for driving the gates of the field effect transistors (FETs) FET1 to FET4 having an H bridge configuration, an H bridge circuit 373 connected and configured in an H shape with four FET1 to FET4, and the battery 14 The relay contact 13 of the power supply relay for turning on / off the power supply to the H bridge circuit 373, the boost power source 374 for boosting the voltage of the FET gate drive circuit 372, and the current detection connected to the H bridge circuit 373 It consists of low resistance shunt resistors R1 and R2.

  The FET1 and FET2 are turned on / off by a PWM (pulse width modulation) signal having a duty ratio D1 determined based on the current control value E, and the magnitude of the current Ir that actually flows through the motor 20 is controlled. Further, the FET 3 and the FET 4 are driven by a PWM signal having a duty ratio D2 defined by a predetermined linear function equation (D2 = a · D1 + b where a and b are constants) in a region where the duty ratio D1 is small, and the duty ratio D2 is also set. After reaching 100%, it is turned ON / OFF according to the rotation direction of the motor 20 determined by the sign of the PWM signal. Shunt resistors R1 and R2 are grounded to the H bridge circuit 373, and a motor current detection circuit 38 is connected to the shunt resistors R1 and R2, thereby detecting a motor current i.

  Thus, conventionally, a single CPU calculates a current command value based on the steering torque T and the motor current i, and controls the drive of the motor 20 based on the current command value. In this case, a steering torque direction signal is generated based on the steering torque T by the hard logic or another CPU for the determined motor current driving direction, and the motor is driven only when the steering torque direction signal matches the motor driving direction. Was driving. When detecting an abnormality in the motor drive system, the time from the detection to the determination of the abnormality is constant, and is not always accurate.

  Conventionally, an external WDT (Watch Dog Timer) is provided in one CPU, and a CPU runaway is monitored by inputting a clear pulse from the CPU to the WDT. When a clear pulse is not input within a predetermined time, a reset signal is output from the WDT to the CPU to restart the CPU. When the CPU runaway is monitored using an external WDT, the program runs out of control and the CPU is runaway, and is restarted by a reset signal from the WDT. However, in the case of a failure that causes the program to run away again in the same place, the motor output state and the stop state occur alternately, causing an unpleasant state for the driver.

  Conventionally, there are systems with two CPUs in order to increase safety and reliability. In such a system with two CPUs, one CPU performs control operations and the other CPU monitors them. In this case, in order to confirm that the monitored CPUs are operating normally, it is necessary for the two CPUs to monitor the CPU runaway each other. Also, when monitoring CPU runaway by sending and receiving pulse signals to and from each other in a system using two CPUs, the program itself does not operate normally and only outputs a monitoring pulse to detect runaway. In some cases, the pulse signal that was not able to be obtained or that was normally output due to noise was erroneously measured and erroneously detected.

  As a control device that solves the above problems, there is one disclosed in Japanese Patent Laid-Open No. 2001-18819 (Patent Document 1). However, each of the input unit, the output unit, and the arithmetic unit is monitored for abnormality by only one circuit. Therefore, if the circuit itself malfunctions and the malfunction monitoring function is disabled, the malfunction may be overlooked. There wasn't. For example, if an abnormality of the processing circuit that cannot be detected by WDT occurs and the abnormality monitoring function of the input unit or the output unit is disabled, or if both WDT and the processing circuit become abnormal at the same time, The occurrence of abnormality may not be recognized. For this reason, a configuration in which abnormality monitoring of the input unit, the output unit, and the arithmetic unit is performed by two separate circuits is desired. However, since the configuration includes only one processing circuit and one WDT, double monitoring is realized. I couldn't.

  Japanese Patent Laid-Open No. 2003-26024 (Patent Document 2) discloses a main MCU (main CPU) that performs arithmetic processing for motor control and abnormality monitoring of input / output units, and a sub that performs abnormality monitoring of the main MCU and input / output units. An MCU (slave CPU) and an external WDT that monitors the abnormality of the main MCU are provided. The output circuit for driving the external WDT and H-bridge is a single ASIC (specific application IC), and the fail-safe function is reliable. Highly realized, and the circuit configuration is relatively simple.

  However, in the control device disclosed in Patent Document 2, in the monitoring by the mutual monitoring of the main CPU and the slave CPU, which are the two processing circuits, and the WDT for self-monitoring, synchronization due to the difference in the operation clock frequency of each CPU (MCU). There is a problem that the deviation occurs.

JP 2001-18819 A JP 200326024 A

  As described above, in the conventional device, in the control device of the electric power steering device constituted by a plurality of CPUs, when the operation clock frequencies of the CPUs are different, a synchronization shift occurs immediately after the activation of the CPUs. In this case, as shown in the prior art, when performing diagnosis of a system that needs to exchange information between CPUs, if individual CPUs are not synchronized due to differences in operating clock frequency, etc. May cause an erroneous detection of an abnormality caused by a synchronization shift.

  The present invention has been made under the circumstances as described above, and an object of the present invention is to provide a main control unit (CPU or MCU, MPU (Micro Processor Unit, etc.)) and a slave control unit (CPU, MCU, MPU, etc.). Control method of electric power steering apparatus that prevents malfunction of cooperative operation of a plurality of control units and improves safety and reliability even if the operation clock frequency of a system composed of a plurality of control units is different And providing a control device.

  The present invention provides a current command value calculation unit that calculates a current command value based on a steering torque generated on a steering shaft and a vehicle speed signal, and applies a steering assist force to the steering mechanism based on the current value of the motor and the current command value. And a drive control unit that controls the drive of the motor, and a control of an electric power steering device that includes a main control unit and a slave control unit that can communicate with each other between the current command value calculation unit and the drive control unit Regarding the method, the above object of the present invention is to confirm that the power supply voltage in the apparatus has become the operating range voltage, that predetermined data has been received from another control apparatus, or that the specific circuit is normal during the initial diagnosis. When it is determined that the specific condition is satisfied, the main control unit notifies the slave control unit of synchronization, and predetermined operations of the main control unit and the slave control unit are performed simultaneously. It is accomplished by synchronizing to start.

  Further, the object of the present invention is that the synchronization is performed in a state in which the steering assist force is not generated, or the synchronization is performed from the main control unit to the slave control unit. A standby state release command is transmitted to the slave control unit that has been received so that only the slave control unit advances to the previous step, or the main control unit changes the level of the port signal to the slave control unit. The synchronization is performed by notifying, or the synchronization is performed through a cross bus of the main control unit and the slave control unit, or through a common shared memory. This is achieved more effectively.

  The present invention provides a current command value calculation unit that calculates a current command value based on a steering torque generated on a steering shaft and a vehicle speed signal, and applies a steering assist force to the steering mechanism based on the current value of the motor and the current command value. And a drive control unit that controls the drive of the motor, and a control of an electric power steering device that includes a main control unit and a slave control unit that can communicate with each other between the current command value calculation unit and the drive control unit Regarding the device, the above object of the present invention is to confirm that the power supply voltage in the device has become the operating range voltage, that predetermined data has been received from another control device, or that the specific circuit is normal during the initial diagnosis. When it is determined that the specific condition is satisfied, the main control unit notifies the slave control unit of synchronization, and predetermined operations of the main control unit and the slave control unit are performed simultaneously. It is accomplished by providing a synchronizing means for synchronizing to start.

  The object of the present invention is to perform the synchronization in a state where the synchronization means does not generate the steering assist force, and transmits a standby state release command from the main control unit to the slave control unit, Only the received slave control unit proceeds to the previous step, or the synchronization means performs the synchronization without generating the steering assist force, and the main control unit The synchronization is performed by notifying the slave control unit of a change in the level of the port signal, or the synchronization means does not generate the steering assist force. It is more effective by performing synchronization and performing the synchronization via a crossing bus of the main control unit and the slave control unit or via a common shared memory. It is achieved.

  According to the present invention, even if the operating clock frequency of a system composed of a plurality of CPUs is different, each CPU can recognize it, or the main CPU can notify the slave CPU in some form. Since synchronization is achieved by providing possible functions, it is possible to prevent malfunctions caused by cooperative operations among a plurality of CPUs.

It is a block diagram which shows the structural example of the control apparatus of the electric power steering apparatus which concerns on this invention. It is a flowchart which shows operation | movement of an electric power steering apparatus. It is a flowchart which shows the operation example of this invention. It is a time chart which shows the operation example of this invention. It is a system configuration diagram showing a general connection relationship between a main CPU and a plurality of slave CPUs. It is a flowchart which shows the operation example of main CPU. It is a flowchart which shows the example of a synchronization process of main CPU. It is a flowchart which shows the operation example of a slave CPU. It is a figure which shows an example of a general steering mechanism. It is a figure which shows an example of a general CPU mechanism. It is a block diagram which shows an example of a structure of the control apparatus of the conventional electric power steering apparatus.

DESCRIPTION OF SYMBOLS 1 Steering handle 2 Column shaft 3 Reduction gear 4A and 4B Universal joint 5 Pinion rack mechanism 6 Tie rod 10, 40 Torque sensor 11 Ignition key 12, 41 Vehicle speed sensor 14 Battery 20 Motor 30 Control unit 37 Motor drive circuit 38 Motor current detection circuit 42 External WDT
50 Main CPU (Main Control Unit)
60 Slave CPU (Slave Control Unit)

  In the present invention, even if the operating clock frequency of a system composed of a plurality of control units (hereinafter referred to as “CPU”, including MCU, MPU, etc.) is different, a specific condition of hardware is established. As a result, synchronization is performed at a stage prior to processing executed by two or more CPUs, so that malfunction due to cooperative operation among multiple CPUs can be prevented, and processing is executed after such synchronization . The synchronization processing is performed during the initial diagnosis when the electric power steering apparatus does not generate assist, and whether the specific condition of the hardware is satisfied can be recognized by each CPU, or notified from the main CPU to the slave CPU in some form. This is possible by providing various functions that can be performed.

  In the present invention, the dual monitoring of the input / output unit is performed by the main CPU and the slave CPU, and the dual monitoring of the main CPU is performed by the slave CPU and the external WDT, thereby realizing the fail-safe concept. For this reason, the safety and reliability of the electric power steering device can be secured sufficiently high. Moreover, since only one external WDT for monitoring the main CPU is provided for the main CPU, the circuit configuration is relatively simple and an increase in size can be avoided.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows a configuration example of the present invention corresponding to FIG. 11, and the configuration will be described first.

  The control device according to the present invention includes a main CPU 50 having a WDT 51 for main CPU self-monitoring and a WDT 52 for mutual monitoring, and a slave CPU 60 having a WDT 61 for mutual monitoring and a WDT 62 for slave CPU self-monitoring. In addition to the motor control process, the main CPU 50 has a fail-safe function for monitoring an abnormality of the input / output unit and executing an abnormality handling process when an abnormality is detected. For example, whether or not the system power supply voltage exceeds an allowable range (operating voltage range) is monitored at a predetermined cycle. If the system power supply voltage exceeds the allowable range, the driving of each FET in the motor drive circuit 37 is forcibly stopped. That is, an assist stop process for turning off the relay contact 13 is performed while maintaining each FET in the off state via the FET gate drive circuit 372. Further, when the overcurrent state of the motor 20 is determined based on the motor current i input from the current detection circuit 38 and it is determined that the abnormal overcurrent state is detected, the same assist stop process is executed.

  On the other hand, the slave CPU 60 does not execute arithmetic processing for motor control, but has a fail-safe function of monitoring the abnormality of the input / output unit in the same manner as the main CPU 50 and executing the same abnormality handling process when an abnormality is detected. That is, double monitoring of the input unit and the output unit is realized by the two CPUs 50 and 60. Note that abnormality monitoring by each CPU is performed separately, and if any one of the CPUs detects an abnormality, a predetermined abnormality handling process is executed. For example, the driving of the motor 20 is not executed unless the two CPUs 50 and 60 both permit energization of the motor 20, that is, the state where the assist stop process is not instructed.

  In FIG. 1, one slave CPU (60) is provided for one main CPU 50, but a plurality of slave CPUs may be used.

  The steering torque T from the torque sensor 40 is input to the main CPU 50 and the slave CPU 60, the vehicle speed V from the vehicle speed sensor 41 is also input to the main CPU 50 and the slave CPU 60, and the motor current i detected by the motor current detection circuit 38 is also the main CPU 50. And input to the slave CPU 60. An external WDT 42 for monitoring the main CPU is connected to the main CPU 50, and the relay contact 13 is on / off controlled by a fail relay drive circuit 43.

  In such a configuration, communication and monitoring are performed between the main CPU 50 and the slave CPU 60 by a method as disclosed in Patent Document 1. That is, the main CPU 50 and the slave CPU 60 mutually monitor operation (runaway) by serial communication, and the main CPU 50 determines whether or not a normal command has been received from the slave CPU 60 at all times. When a normal command is received, the built-in slave WDT 52 is cleared and the process returns to the standby state. If it is determined that a normal command has not been received, “+1” is added to the built-in WDT 52 to determine whether the count value of the WDT 52 is equal to or greater than a predetermined threshold. If the count value is equal to or less than the threshold value, the process returns to the standby state. If the count value exceeds the threshold value, the runaway of the slave CPU 60 is confirmed, the motor drive signal is turned OFF, and the relay OFF signal from the fail relay drive circuit 43 is used. The contact 13 of the relay 44 is turned off. When the slave CPU 60 determines runaway, the motor drive signal is not turned off, but a motor drive inhibition signal is output to stop the motor drive circuit 37, and the relay 44 is turned off by the relay OFF signal.

  Also, if the CPU runaway detection times of the self-monitoring WDTs 51 and 62 are set to the same time, when the two CPUs run away at the same time, both control units are temporarily suspended after restarting by the self-monitoring WDTs 51 and 62. Therefore, when the mutual monitoring does not function normally and a similar program runaway occurs again, there is a possibility that the restart by the self-monitoring WDTs 51 and 62 is repeated. Therefore, the runaway detection time of the main CPU monitoring WDT 51 and the runaway detection time of the slave CPU monitoring WDT 62 are made different so that the runaway can be detected more reliably.

  Here, as shown in FIG. 2, when the ignition key is turned on (step S1), an initial diagnosis is performed (step S2), and the operation of the electric power steering apparatus is OK (step S3). Assist is started (step S4). When the ignition key is turned off (step S5), the end condition is determined and the process ends (step S6). In addition, also when the initial diagnosis is NG in the above step S3, the end condition is determined and the process ends.

  In the present invention, at the time of the initial diagnosis (step S2), synchronization between the main CPU 50 and the slave CPU 60 described below is performed.

  The operation of the present invention will be described with reference to the flowchart of FIG. 3 and the time chart of FIG. 4. When the ignition key is turned on at time t1 (step S10, FIG. 4A), the system starts from time t2 immediately after that. The power supply voltage rises as shown in FIG. 4B, and the power supply voltage of the boost power supply 374 gradually rises as shown in FIG. 4C. When the system power supply voltage enters the operating range voltage (allowable range) (step S11, time t2 in FIG. 4), and the power supply voltage of the boost power supply 374 enters the operating range voltage (allowable range) (step S12, FIG. 4). At time t4), the main CPU 50 notifies the slave CPU 60 of the start of diagnosis (step S13), and starts diagnosis (monitoring) as described above from time t4 in FIG. When the ignition key is turned on, the system power supply voltage rapidly rises as shown in FIG. 4B, enters the operating range voltage at time t2, and further maintains the saturation voltage after time t3. Further, the boosted power supply voltage gradually rises as shown in FIG. 4C, enters the operating range voltage at time point 4, and holds the saturation voltage after time point t5.

  On the other hand, as shown in FIG. 4D, the operation state of the main CPU 50 is waiting for diagnosis (waiting for charging) until time t4, and is in the diagnosis state after time t4.

  Regarding the processing for synchronization between the two CPUs 50 and 60, the initial diagnosis is designed so that the main CPU 50 and the slave CPU 60 can only be performed within the operating range voltage, and the boost power source 374 for driving the motor 20 from the system power source voltage. Wait until a sufficient amount of charge has been charged, and after that, the circuit is fully charged and the boosted power supply voltage is higher than a certain voltage (after time t4 in FIG. 4) and applied to the CPUs 50 and 60. Start. The reason for this is that if the system power supply voltage is not within the operating range voltage, the booster circuit will not be sufficiently charged, and when the charging to the booster circuit is completed, the boosted power supply voltage is recognized as being within the operating range voltage. Is possible. Therefore, if diagnosis (monitoring) is started upon completion of charging of the booster circuit, there is no difference in diagnosis timing between the two CPUs.

  In the above state, the main CPU 50 notifies the slave CPU 60 of the start of the initial diagnosis via a serial line or the like, thereby synchronizing the main CPU 50 and the slave CPU 60 (step S14). Here, a synchronization method using a serial line will be described.

  FIG. 5 shows a connection relationship between a general main CPU (corresponding to the main CPU 50 in FIG. 1) and a plurality (n) of slave CPUs (corresponding to the slave CPU 60 in FIG. 1). It is in a state of waiting for an operation in accordance with a command from the main CPU. That is, the slave CPU side remains in a standby state after the main CPU is activated until a process start command is received from the main CPU.

  As shown in FIG. 6, the main CPU first performs system startup processing (step S20), and performs synchronization processing for performing cooperative operation with other CPUs, that is, slave CPUs (step S21). (Step S22). FIG. 7 shows the synchronization process of the main CPU (step S21). First, it is determined whether the hardware condition is satisfied (step S211). (Step S212). On the other hand, as shown in FIG. 8, the slave CPU first performs system startup processing (step S220), determines whether or not a standby state release request is received from the main CPU (step S221), A cooperative operation with the CPU is performed (step S222). That is, unless there is a standby state cancellation request from the main CPU, the slave CPU performs synchronization by preventing it from proceeding further.

  After the synchronization as described above, the diagnosis between the CPUs 50 and 60 is executed (step S15), and after the execution of the diagnosis between the CPUs is completed, the process proceeds (returns) to normal processing (step S16). Note that there is no limitation on the means for notification because it is only necessary to be able to notify the CPU 50 and 60 in some form. Further, if each CPU can recognize the boost power supply voltage of the booster circuit described in the embodiment, the notification from the CPU is not required.

  In the above example, the synchronization is performed using the serial line, but the main CPU 50 changes the level of the port signal to the slave CPU 60 (for example, the LOW level is set as standby and the HIGH level is notified of synchronization). Thus, the slave CPU 60 can be notified of synchronization, and if there is an intersection bus between the main CPU 50 and the slave CPU 60, the synchronization notification can be performed using the intersection bus. When there is a shared memory that is shared by the main CPU 50 and the slave CPU 60, identification information may be given to the shared memory, and the main CPU 50 may notify the synchronization by writing the start of synchronization on the shared memory. it can. Furthermore, the main CPU 50 and the slave CPU 60 individually determine whether the hardware specific conditions are satisfied and notify the synchronization, or information received from other control devices via the communication line (for example, engine speed, vehicle speed, etc.) ) Can also be notified of synchronization.

  As the diagnosis after synchronization, regarding the execution of diagnosis with the slave CPU 60 in step S14 of FIG. 3, immediately after the synchronization of each CPU is realized, the ports connected between the CPUs (in the state of HI or LOW) The port is used to identify whether or not the port is normally connected. This is performed under the initiative of the main CPU 50, and when the slave CPU 60 can recognize the signal level as changed by the main CPU 50, the inter-CPU signal line is identified as normal. If the signal level is not intended, it is determined that the inter-CPU signal line is abnormal. At this time, if the synchronization is not established between the CPUs, there is a difference between the timing at which the main CPU 50 changes the signal level and the timing at which the slave CPU 60 recognizes the signal, thereby erroneously detecting a failure in the signal line between the CPUs. However, such a problem does not occur if synchronization is achieved.

  In the above description, whether or not the specific condition is satisfied is determined based on the voltage of the boost power supply voltage. However, the predetermined initial diagnosis (the initial diagnosis for a specific circuit among several initial diagnoses) is normally completed and specified. The condition may be satisfied when the normality of the circuit is confirmed, or the condition may be satisfied when data is received from communication with another control device such as a CAN (Controller Area Network). In addition, a capacitor is installed in the power supply circuit for driving the motor, the power supply for charging is received from the battery, the charging circuit is charged with a constant time constant, and the charging state to the charging circuit is monitored. Thus, the specific condition may be satisfied when a predetermined charge or more is performed. Further, in the case of a system capable of monitoring the CPU temperature, the temperature rise after the CPU is started (CPU temperature rises during processing) is a predetermined value or more, or (current temperature-initial temperature) or estimated temperature value The specific condition may be satisfied when the voltage exceeds a predetermined value, or the battery voltage is monitored after the CPU is started, and the specific condition is satisfied when a state satisfying the predetermined voltage condition continues for a certain period of time. It may be established. It is also possible to implement a combination of the above methods.

Claims (9)

A current command value calculation unit for calculating a current command value based on a steering torque generated on a steering shaft and a vehicle speed signal; and the motor for applying a steering assist force to a steering mechanism based on the current value of the motor and the current command value. In the control method of the electric power steering apparatus comprising a drive control unit for driving control, and a main control unit and a slave control unit that can communicate with each other, the current command value calculation unit and the drive control unit,
When it is determined that the specific condition that the internal power supply voltage has become the operating range voltage, that predetermined data has been received from another control device, or that the specific circuit has been confirmed to be normal during the initial diagnosis, has been established. The control of the electric power steering apparatus, characterized in that the main control unit notifies the slave control unit of synchronization, and synchronizes so that predetermined operations of the main control unit and the slave control unit start simultaneously Method.   The method for controlling the electric power steering apparatus according to claim 1, wherein the synchronization is performed in a state where the steering assist force is not generated.   The electric power according to claim 2, wherein the synchronization is performed by transmitting a standby state release command from the main control unit to the slave control unit so that only the received slave control unit proceeds to the previous step. Steering device control method.   The method for controlling the electric power steering apparatus according to claim 2, wherein the synchronization is performed by notifying the slave control unit of a change in level of a port signal from the main control unit.   The method of controlling an electric power steering apparatus according to claim 2, wherein the synchronization is performed through a crossing bus of the main control unit and the slave control unit or through a common shared memory. A current command value calculation unit for calculating a current command value based on a steering torque generated on a steering shaft and a vehicle speed signal; and the motor for applying a steering assist force to a steering mechanism based on the current value of the motor and the current command value. In the control device of the electric power steering device comprising a drive control unit for driving control, and a main control unit and a slave control unit that can communicate with each other, the current command value calculation unit and the drive control unit,
When it is determined that the specific condition that the internal power supply voltage has become the operating range voltage, that predetermined data has been received from another control device, or that the specific circuit has been confirmed to be normal during the initial diagnosis, has been established. The main control unit includes synchronization means for notifying the slave control unit of synchronization and synchronizing so that predetermined operations of the main control unit and the slave control unit start simultaneously. Control device for electric power steering device.   The synchronization means performs the synchronization in a state where the steering assist force is not generated, transmits a standby state release command from the main control unit to the slave control unit, and receives only the slave control unit received 7. The control device for an electric power steering device according to claim 6, wherein the control is advanced to the previous step.   The synchronization means performs the synchronization in a state where the steering assist force is not generated, and performs the synchronization by notifying the slave control unit of the level change of the port signal from the main control unit. The control device for an electric power steering device according to claim 6.   The synchronization means performs the synchronization in a state where the steering assist force is not generated, and also performs the synchronization via a cross bus of the main control unit and the slave control unit or through a common shared memory. The control device for the electric power steering apparatus according to claim 6, wherein:

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