JP4035986B2 - Control device for electric power steering device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an electric power steering device that applies a steering assist force by a motor to a steering system of an automobile or a vehicle, and in particular, includes two main and sub control units (CPU or MCU: Micro Controller Unit). The present invention relates to a control device for an electric power steering apparatus that has improved controllability and safety by performing motor control on the one hand and monitoring drive system abnormality on the other hand.
[0002]
[Prior art]
An electric power steering device that biases an automobile or a vehicle steering device with an auxiliary load by the rotational force of a motor assists the steering shaft or rack shaft with a transmission mechanism such as a gear or a belt via a reduction gear. The load is 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 the feedback control, the motor applied voltage is adjusted so that the difference between the current command value and the motor current detection value becomes small. Generally, the adjustment of the motor applied voltage is a duty of PWM (pulse width modulation) control. This is done by adjusting the tee ratio.
[0003]
Here, the general configuration of the electric power steering apparatus will be described with reference to FIG. 9. The shaft 2 of the steering handle 1 is connected to the reduction gear 3, the universal joints 4 a and 4 b, the pinion rack mechanism 5, and the tie rod of the steering wheel. 6. The shaft 2 is provided with a torque sensor 10 that detects the steering torque of the steering handle 1. A motor 20 that assists the steering force of the steering handle 1 is coupled to the shaft 2 via the clutch 21 and the reduction gear 3. Has been. The control unit 30 that controls the power steering device is supplied with electric power from the battery 14 via the ignition key 11 and the relay 13, and the control unit 30 is detected by the steering torque T detected by the torque sensor 10 and the vehicle speed sensor 12. The steering assist command value I of the assist command is calculated based on the vehicle speed V, and the current supplied to the motor 20 is controlled based on the calculated steering assist command value I. The clutch 21 is ON / OFF controlled by the control unit 30 and is ON (coupled) in a normal operation state. The clutch 21 is turned off (disconnected) when the control unit 30 determines that the power steering device is out of order and when the power supply (voltage Vb) of the battery 14 is turned off by the ignition key 11 and the relay 13. The
[0004]
The control unit 30 is mainly composed of a CPU, and general functions executed by programs in the CPU are as shown in FIG. For example, the phase compensator 31 does not indicate a phase compensator as independent hardware, but indicates a phase compensation function executed by the CPU. The function and operation of the control unit 30 will be described. The steering torque T detected and input by the torque sensor 10 is phase-compensated by the phase compensator 31 in order to improve the stability of the steering system, and the phase-compensated steering torque. TA is input to the steering assist command value calculator 32. The vehicle speed V detected by the vehicle speed sensor 12 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. The proportional output is input to the adder 30B and to the integration calculator 36 for improving the characteristics of the feedback system. The outputs of the differential compensator 34 and the integration calculator 36 are also added to the adder 30B, and the current command 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.
[0005]
As described above, conventionally, a single CPU calculates a current command value based on a torque signal (steering torque T) and a current detection value i, and drives and controls the motor based on the current command value. In this case, a steering torque direction signal is generated based on the torque signal by the hard logic or another CPU for the determined motor current driving direction, and the motor is turned on only when the steering torque direction signal matches the motor driving direction. I was driving. Further, when detecting an abnormality in the motor drive system, the time from detection to determination of the abnormality is constant, and is not always accurate.
[0006]
In the electric power steering apparatus as described above, the inertia of the motor increases as the output of the motor increases, and it has become necessary to compensate for the inertia of the motor in order to ensure steering characteristics. Due to the control for compensating the inertia, the direction based on the torque signal which has been conventionally performed and the direction in which the motor is actually driven have become inconsistent. Thereby, although the control including the inertia compensation function is operating normally, the motor control is temporarily stopped by the other control unit outputting the torque direction signal based on the torque signal. Such inconvenience occurred. In other words, the conventional direction interlock based on the direction of the steering torque has become incompatible with an actual system.
[0007]
Conventionally, when detecting an abnormality in the motor drive system, the time from detection to determination of the abnormality is constant. However, when the abnormality is detected by obtaining the difference between the current command value and the motor current detection value, if there is a large difference, it is clearly considered that there is an abnormality, and it is necessary to stop the system immediately. In addition, when a small difference is detected, erroneous detection due to the influence of noise or the like can be considered, so it is necessary to take time to determine.
[0008]
Further, when CPU runaway is monitored using an external WDT as in the prior art, runaway occurs in the CPU because the program does not operate normally, and it 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 a dangerous state for the driver.
[0009]
On the other hand, in a system including two control units, when one control unit performs control calculation and the other control unit monitors it, it is confirmed that the monitoring control unit is operating normally. Therefore, the two control units need to monitor the CPU runaway each other.
[0010]
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 continues to output only the monitoring pulse, and runaway cannot be detected. In some cases, a pulse signal normally output due to noise or noise is erroneously measured and erroneously detected.
[0011]
In order to solve such a problem, especially when controlling a motor having a large inertia, the main and sub digital control units (CPU or MCU) are provided, the power steering is controlled by one control unit, and the other is controlled. A control device for an electric power steering apparatus that has improved controllability and safety by monitoring each other with a control unit has been disclosed by the applicant of the present application (Japanese Patent Laid-Open No. 2001-18819).
[0012]
FIG. 1 is a block diagram illustrating a functional configuration example of a current command calculation unit in a control unit of a conventional example. A current detection value Id of a motor controlled by a first control unit (referred to as “main MCU”), a first When a failure is detected in the main MCU and the motor drive system by comparing the current command value Irs calculated in the second control unit (referred to as “sub MCU”) with the current abnormality monitoring unit, and an abnormality is detected. In addition, at least one of the motor drive signal and the relay is cut off.
[0013]
The main MCU 101 and the sub MCU 102 all generate a motor drive signal (current command value) Ir based on the torque signal Tr, the vehicle speed signal Vs, the current detection value Id, and the motor terminal voltage Vm. The motor drive signal from the main MCU 101 Only (current command value) Ir is input to the motor drive circuit 110, and the current command value Ir calculated by the sub MCU 102 is used for monitoring. The torque signal Tr is generally formed of a pair of signals in order to detect an abnormality of the torque sensor, etc., and is input to the main MCU side for convenience Trm, and input to the sub MCU side Trs. That is to say.
[0014]
That is, the main MCU 101 and the sub MCU 102 both calculate the current command value Ir based on the torque signal Tr, the vehicle speed Vs, the motor current detection value Id, and the motor terminal voltage Vm, and the motor angular speed estimation unit 120, the motor inertia compensation unit. 121, a convergence control unit 122, a steering assist command value calculation unit 123, a center response improvement unit 124, a robust stabilization compensation unit 125, and adders 130 and 131. The motor angular velocity estimation unit 120 calculates a counter electromotive voltage of the motor 200 from the motor current detection value Id and the motor terminal voltage Vm, and estimates the motor angular velocity ω from the counter electromotive voltage. The estimated motor angular velocity ω is input to the motor inertia compensation unit 121 and the convergence control unit 122, the output of the motor inertia compensation unit 121 is input to the adder 131, and the output of the convergence control unit 122 is input to the adder 130. Is done. The steering assist command value calculation unit 123 calculates a base value of the motor current command value Ir based on the torque signal Tr, and the center responsiveness improvement unit 124 also calculates the base of the motor current command value Ir based on the torque signal Tr. The calculated value is calculated, and any calculated value is input to the adder 130. The added value of the adder 130 is input to the robust stabilization compensator 125, the output of which is input to the adder 131, and the added value of the adder 131 is the motor current command value Ir. The convergence control unit 122 and the steering assist command value calculation unit 123 use the vehicle speed signal Vs as a parameter, and the convergence control unit 122 applies a brake to the operation of the steering wheel to improve the yaw convergence of the vehicle. The motor inertia compensation unit 121 compensates for the inertia and friction of the motor 200. Further, the center responsiveness improvement unit 124 improves the control responsiveness in the vicinity of the neutral position of the steering and realizes smooth and smooth steering. The robust stabilization compensation unit 125 is disclosed in Japanese Patent Laid-Open No. 8-290778. And a characteristic expression G (s) = (s 2 + a 1 · s + a 2) / (s 2 + b 1 · s + b 2) where s is a Laplace operator, and from the inertia element and the spring element included in the detected torque The peak value of the resonance frequency of the resonance system is removed to compensate for the phase shift of the resonance frequency that hinders the stability and responsiveness of the control system. Note that a1, a2, b1, and b2 in the characteristic equation G (s) are parameters determined by the resonance frequency of the resonance system.
[0015]
Further, the motor angular velocity estimation unit 120 may perform angular velocity estimation by a method disclosed in JP-A-10-109655, or may perform angular velocity estimation described in JP-A-10-338152 by the present applicant. . That is, by defining different motor drive system impedance models for the intermittent mode and the continuous mode, the motor angular velocity is estimated in consideration of the influence of the drive system on the drive system impedance. When Io is a current value for switching from the intermittent mode to the continuous mode and K _T · ω is an estimated value of the back electromotive force, the following formulas (1) and (2) are used.
[0016]
When I <Io K _T · ω = Vm−R1 · i (1)
When I ≧ Io K _T · ω = Vm− (R2 · i + b) (2)
Where R1 is the impedance of the intermittent mode at the reference temperature, R2 is the impedance of the continuous mode at the reference temperature, and b is a constant.
[0017]
When the sub MCU 102 determines runaway, the motor drive signal Ir is not turned off, but the motor drive inhibition signal Mp is output to stop the motor drive circuit 110, and the relay 111 is turned on by the relay ON / OFF signal RS2. Is turned off. This is because the motor current command value Irs generated by the sub MCU 102 is for monitoring and is not supplied to the motor drive circuit 110.
[0018]
[Problems to be solved by the invention]
In the configuration as described above, the difference between the main torque signal and the sub torque signal fluctuates due to the temperature drift of the torque sensor, resulting in a difference between the current command value Irs of the sub MCU and the current detection value Id of the motor controlled by the main MCU. However, there is a problem that it is determined that the motor drive system has failed even though it has not failed. FIG. 2 is a diagram showing that the difference between the main torque signal and the sub torque signal appears as an error in the steering assist command value.
[0019]
The present invention has been made in view of such problems of the prior art, and compensates for the difference (offset) between the main torque signal and the sub torque signal due to temperature drift to prevent erroneous determination due to a calculation error due to the offset. It is an object of the present invention to provide a control device for an electric power steering device.
[0020]
[Means for Solving the Problems]
An object of the present invention is to control the motor of an electric power steering apparatus including a torque sensor for detecting a steering torque generated in a steering shaft, a vehicle speed sensor, and a motor for providing a steering assist force to the steering mechanism. In the control device of the electric power steering device, the control device includes a motor drive circuit that drives the motor, a first control unit that supplies a current command value that is a motor drive signal to the motor drive circuit, and a current of the motor A motor current detection circuit that detects the abnormality, and a second control unit that monitors the abnormality of the first control unit and the motor drive system by monitoring the abnormality of the detected motor current detection value (Id). In addition, the first control unit may include a main torque signal and a sub torque signal, which are a pair of torque signals output from the torque sensor. A vehicle speed signal output from the main torque signal and the vehicle speed sensor, and an offset calculation unit that calculates an offset signal that is a difference between the main torque signal and a communication unit that transmits the offset signal to the second control unit. The steering assist command value calculated based on the motor current detection value and the motor terminal voltage to calculate the current command value, the second control unit, the communication unit that receives the offset signal; An offset compensator for correcting the input sub-torque signal based on the received offset signal, a steering assist command value calculated based on the corrected sub-torque signal and the vehicle speed signal, and the motor current calculated current command value (Irs) based on the detected value and the motor terminal voltage, comparing said current command value (Irs) and said detected motor current value and (Id) It is achieved by a control device for an electric power steering apparatus characterized by comprising a current abnormality monitoring unit that monitors the motor current detection value (Id) abnormal Te.
[0021]
Another object of the present invention is to control the motor of an electric power steering apparatus that includes a torque sensor that detects a steering torque generated in a steering shaft, a vehicle speed sensor, and a motor that applies a steering assist force to the steering mechanism. In the control device for the electric power steering apparatus for the above, the control device includes a motor drive circuit that drives the motor, a first control unit that gives a current command value that is a motor drive signal to the motor drive circuit, and the motor A motor current detection circuit for detecting the current of the motor, and a second control unit for monitoring the abnormality of the first control unit and the motor drive system by monitoring the abnormality of the detected motor current detection value (Id). The first control unit further includes a main torque signal that is a pair of torque signals output from the torque sensor and a sub-control. And a communication unit that inputs the main torque signal of the torque signal and transmits the main torque signal to the second control unit, and the main torque signal and the vehicle speed signal output from the vehicle speed sensor. A communication unit that calculates the current command value based on the steering assist command value calculated based on the motor current detection value and the motor terminal voltage, and the second control unit receives the transmitted main torque signal And an offset calculation unit that calculates an offset signal that is a difference between the input sub torque signal and the received main torque signal, and an offset compensation unit that corrects the sub torque signal based on the offset signal, A steering assist command value calculated based on the corrected sub torque signal and the vehicle speed signal, the motor current detection value, and the Current command value based on over data terminal voltage (Irs) calculates the abnormality monitoring of the current command value (Irs) and said detected motor current value (Id) and the motor current detection value by comparing (Id) The present invention is also achieved by a control device for an electric power steering apparatus characterized by including a current abnormality monitoring unit that performs the above operation.
[0022]
Further, the electric power is characterized in that the transmission of the offset signal or the main torque signal from the first control unit to the second control unit is performed at the initial start of both the control units and every predetermined period. This is achieved more effectively by the control device of the steering device.
[0023]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a control device for an electric power steering apparatus that compensates for a difference (offset) between a main torque signal and a sub torque signal due to a temperature drift and prevents erroneous determination due to a calculation error due to the offset.
[0024]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0025]
FIG. 3 is a block diagram showing the first embodiment of the present invention. The main torque signal Trm, the sub torque signal Trs from the torque sensor 201, and the vehicle speed signal Vs from the vehicle speed sensor 202 are inputted to the main MCU 101, and the torque sensor 201 The sub torque signal Trs and the vehicle speed signal Vs from the vehicle speed sensor 202 are input to the sub MCU. The motor drive signal Ir calculated by the main MCU 101 is input to the motor drive circuit 110, and the motor drive circuit 110 drives the motor 200 based on the motor drive signal Ir. The main MCU 101 includes a sub WDT 101S and a main MCU self-monitoring WDT 101M for mutual monitoring, and the sub MCU 102 also includes a main WDT 102M and a sub MCU self-monitoring WDT 102S for mutual monitoring. The relay 111 that turns ON / OFF the input of the battery 203 is ON / OFF controlled by the relay ON / OFF signal RS1 output from the main MCU 101 and the relay ON / OFF signal RS2 output from the sub MCU 102, and the current of the motor 200 is The current detection value Id detected by the motor current detection circuit 112 is input to the main MCU 101 and the sub MCU 102 together with the motor terminal voltage Vm, and the motor drive inhibition signal Mp output from the sub MCU 102 is input to the motor drive circuit 110. .
[0026]
The main MCU 101 generates a motor drive signal (current command value) Ir based on the main torque signal Trm, the vehicle speed signal Vs, the current detection value Id, and the motor terminal voltage Vm, and inputs it to the motor drive circuit 110.
[0027]
On the other hand, the sub MCU 102 generates a motor drive signal (current command value) based on the sub torque signal Trs, the vehicle speed signal Vs, the current detection value Id, and the motor terminal voltage Vm, but this is not supplied to the motor drive circuit. Used for current monitoring inside the sub MCU 102.
[0028]
The functional configurations of the main MCU 101 and the sub MCU 102 are as shown in FIG.
[0029]
That is, the main MCU 101 is provided with an offset calculation unit 132, and calculates an offset signal based on the difference between the input main torque signal Trm and the sub torque signal Trs. The communication unit 133 functions to transmit the offset signal to the sub MCU 102.
[0030]
On the other hand, the sub-MCU 102 is provided with a communication unit 133 that receives the offset signal from the main MCU 101 and sends the received offset signal to the offset compensation unit 134 provided in the sub MCU 102. To do. The offset compensator 134 corrects the offset signal with respect to the sub torque signal Trs input to the sub MCU 102, thereby eliminating the calculation error of the steering assist command value shown in FIG. The description of other functions is as described above.
[0031]
In such a configuration, the offset compensation operation of the sub torque signal will be described with reference to the flowchart of FIG.
[0032]
First, in the main MCU, it is determined whether the power is turned on or the set time has elapsed (step S501). If YES, the offset calculation unit 132 reads the main torque signal Trm (step S502). Next, the offset calculator 132 reads the sub torque signal Trs (step S503), performs an offset calculation (step S504), and calculates an offset signal. Further, the offset signal is transmitted to the sub MCU via the communication unit 133 (step S505).
[0033]
Next, the sub MCU receives the offset signal via the communication unit 133 (step S506), reads the sub torque signal Trs (step S507), and the offset compensation unit 134 performs offset correction of the sub torque signal Trs (step S508). ). The sub-torque signal corrected in this way is sent to the steering assist command value calculation unit 123 and is used as a basis for calculating the current command value.
[0034]
Since the temperature drift changes with time, the process returns to step S501 and the offset compensation operation is repeated.
[0035]
FIG. 6 is a block diagram showing a second embodiment of the present invention. A difference in appearance from the first embodiment of FIG. 3 is that the sub torque signal Trs is input only to the sub MCU 102.
[0036]
The functional configurations of the main MCU 101 and the sub MCU 102 in the second embodiment are as shown in FIG. 7, and the main torque signal Trm input to the main MCU 101 is transmitted to the sub MCU 102 via the communication unit 133.
[0037]
On the other hand, an offset calculation unit 132 is provided on the sub MCU 102 side, and an offset signal is calculated based on the received main torque signal Trm and the sub torque signal Trs input to the sub MCU 102. The offset signal is used for offset correction of the sub torque signal Trs in the offset compensator 134.
[0038]
In short, the offset calculation unit of the main MCU in the first embodiment is shifted to the sub MCU side.
[0039]
With such a configuration, a second embodiment of offset compensation of the sub torque signal will be described with reference to the flowchart of FIG.
[0040]
First, in the main MCU, it is determined whether the power is turned on or the set time has elapsed (step S801). If YES, the main torque signal Trm is read (step S802), and the main torque signal Trm is transmitted via the communication unit 133. To the sub MCU (step S803).
[0041]
Next, the sub MCU receives the main torque signal Trm via the communication unit 133 (step S804), reads the input sub torque signal Trs (step S805), and then performs an offset calculation by the offset calculation unit 132. In step S806, an offset signal is calculated. Next, the offset compensation unit 134 performs offset correction of the sub torque signal Trs based on the calculated offset signal (step S807).
[0042]
The sub-torque signal corrected in this way is sent to the steering assist command value calculation unit 123 and is used as a basis for calculating the current command value.
[0043]
Since the temperature drift changes with time, the process returns to step S801 and the offset compensation operation is repeated.
[0044]
The present invention can be applied not only to column type and pinion type electric power steering apparatuses, but also to rack assist type electric power steering apparatuses. In the above description, the MCU has been described, but the same applies to the CPU.
[0045]
【The invention's effect】
According to the control device for an electric power steering apparatus according to the present invention, it is possible to compensate for the difference (offset) between the main torque signal and the sub torque signal due to temperature drift. There is an effect that it can be prevented.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating a functional configuration example of a current command calculation unit in a control unit of a conventional example.
FIG. 2 is a diagram showing that a difference between a main torque signal and a sub torque signal appears as an error in a steering assist command value.
FIG. 3 is a block diagram showing a first embodiment of the present invention.
FIG. 4 shows a functional configuration of a main MCU 101 and a sub MCU 102 in the first embodiment of the present invention.
FIG. 5 is a flowchart showing the operation of the first embodiment of the present invention.
FIG. 6 is a block diagram showing a second embodiment of the present invention.
FIG. 7 shows a functional configuration of the main MCU 101 and the sub MCU 102 in the second embodiment of the present invention.
FIG. 8 is a flowchart showing the operation of the second exemplary embodiment of the present invention.
FIG. 9 is a structural diagram showing a schematic configuration of an electric power steering apparatus.
FIG. 10 is a block configuration diagram illustrating an example of a control device of the electric power steering apparatus.
[Explanation of symbols]
30 Control unit 101 Main MCU
102 Sub MCU
DESCRIPTION OF SYMBOLS 110 Motor drive circuit 111 Relay 112 Motor current detection circuit 120 Motor angular velocity estimation part 121 Motor inertia compensation part 122 Convergence control part 123 Steering assistance command value calculation part 124 Center response improvement part 125 Robust stabilization compensation part 132 Offset calculation part 133 Communication unit 134 Offset compensation unit 200 Motor 201 Torque sensor 202 Vehicle speed sensor

Claims (4)

  Control device for electric power steering apparatus for controlling said motor of electric power steering apparatus comprising one torque sensor for detecting steering torque generated in steering shaft, vehicle speed sensor, and motor for providing steering assist force to steering mechanism In
  The control device
  A motor drive circuit for driving the motor; a first control unit for giving a current command value which is a motor drive signal to the motor drive circuit; a motor current detection circuit for detecting a current of the motor; and the detected motor Current detection value (Id) A first control unit and a second control unit for monitoring a motor drive system abnormality by monitoring the abnormality of
  The first control unit is configured to calculate an offset signal that is a difference between a main torque signal that is a pair of torque signals output from the torque sensor and a sub torque signal; Based on the steering assist command value calculated based on the main torque signal and the vehicle speed signal output from the vehicle speed sensor, the detected motor current value, and the motor terminal voltage. Calculate the current command value,
  The second control unit includes a communication unit that receives the offset signal and an offset compensation unit that corrects the input sub torque signal based on the received offset signal, and the corrected sub torque signal and Steering assist command value calculated based on the vehicle speed signal, current command value based on the motor current detection value and the motor terminal voltage (Irs) To calculate the current command value (Irs) And the motor current detection value (Id) Compared with the motor current detection value (Id) A control device for an electric power steering apparatus, comprising a current abnormality monitoring unit for monitoring an abnormality in the electric power steering apparatus. Control device for electric power steering apparatus for controlling said motor of electric power steering apparatus comprising one torque sensor for detecting steering torque generated in steering shaft, vehicle speed sensor, and motor for providing steering assist force to steering mechanism In
The control device
A motor drive circuit for driving the motor; a first control unit for giving a current command value which is a motor drive signal to the motor drive circuit; a motor current detection circuit for detecting the current of the motor; and the detected motor A first control unit by monitoring an abnormality of the current detection value (Id) and a second control unit for monitoring an abnormality of the motor drive system, and
The first control unit inputs the main torque signal out of a main torque signal and a sub torque signal, which are a pair of torque signals output from the torque sensor, and sends the main torque signal to the second control unit. A communication unit for transmitting, and the current command based on the steering assist command value calculated based on the main torque signal and the vehicle speed signal output from the vehicle speed sensor, the motor current detection value, and the motor terminal voltage. Calculate the value
The second control unit includes a communication unit that receives the transmitted main torque signal, an offset calculation unit that calculates an offset signal that is a difference between the input sub torque signal and the received main torque signal, An offset compensator for correcting the sub torque signal based on the offset signal, and a steering assist command value calculated based on the corrected sub torque signal and the vehicle speed signal, the motor current detection value, and the motor current command value based on the terminal voltage (Irs) calculates the current for monitoring the electric current command value (Irs) and said detected motor current value (Id) and the motor current detection value by comparing the (Id) abnormal A control device for an electric power steering apparatus, comprising an abnormality monitoring unit.   2. The electric power steering according to claim 1, wherein transmission of an offset signal from the first control unit to the second control unit is performed at an initial stage of activation of the two control units and at predetermined intervals. Control device for the device.   The electric power according to claim 2, wherein the transmission of the main torque signal from the first control unit to the second control unit is performed at the initial start of both the control units and at predetermined intervals. Control device for steering device.

Images