JP3531250B2 - Control device for electric power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] BACKGROUND OF THE INVENTION The present invention relates to an electric motor for a vehicle steering system.
Electric power to provide steering assist force by the motor
Regarding the control device of the steering device, in particular, rapid steering
Regarding a control device that can perform accurate control even for operation etc.
You. [0002] 2. Description of the Related Art Conventionally, electric power steering systems
The control device includes a torque detection signal detected by the torque sensor,
Assist power is calculated based on the vehicle speed detected by the vehicle speed sensor.
Current (motor drive current), and this assist current is
Supply to the motor
To assist the steering force of the vehicle. FIG.
FIG. This device has a torque detection value T
Of the assist current by a predetermined calculation based on the vehicle speed V
Motor current command value S to be a reference value_ICurrent command to generate
Arithmetic processing 18 and the motor current command value S_IAs a control target
Motor drive signal by PID control (proportional / integral / differential)
S_MPID control processing 19 for calculating the motor drive signal
S_MPWM such as pulse signal with duty ratio corresponding to_*,
D_*And a PWM circuit 29 for generating pulse signals
_*, D_*Is supplied to the electric motor 12 according to the driving current.
Motor drive circuit 30 and drive by motor drive circuit 30
The current value of the current is detected, and the detected current value i_MIs the PID
A current detection circuit 61 that feeds back to the control operation 19;
It is provided with. As described above, based on the detected torque value T and the vehicle speed V,
Motor current command value S_IAnd generate this as the control target
By being input to the steering shaft
The steering assist force corresponding to the steering torque and the vehicle speed is transmitted to the motor 12.
Has occurred. Also, the value i of the motor drive current_MThe
The mode is controlled by the PID control operation 19 as a feedback signal.
Data current command value S_ICalculation of feedback control
Go to motor drive signal S_MBy calculating
Current command value S_IBetter follow-up to changes in
ing. That is, in addition to proportional control by proportional calculation,
Mainly by differential operation for quick response
Differential control and integration calculation mainly to eliminate steady-state deviation
Integral control is performed. [0004] In such feedback control,
Motor drive signal S calculated by calculation_MCorresponding to
By supplying a drive current to the electric motor 12, the vehicle
Additional driver's operation of the steering wheel
The driver will be able to steer
The wheel can be operated lightly. [0005] As described above, the conventional electric motor
In the control device of the power steering device, the PID
The feedback control such as the control is performed.
If it is an operation, the steering assist force will follow this and perform a light operation.
Can be PID control etc. is based on a linear model.
Control within the range of normal steering operation.
The electric motor to be controlled can be approximated with a linear model.
Because it is noh. However, a sudden operation of the steering wheel is performed.
When the operation exceeds the normal operation range, such as when
Can be a problem. For example, a steering wheel
Stop immediately after the tool is suddenly turned vigorously.
This is the case. In such cases, stearin
Follows the generation of steering assist force in response to sudden operation of wheel
Motor current command value S_IFurthermore, motor drive
Signal S_MValue increases, but the actual motor
There is a limit to the drive current that can be supplied to
The motor drive current is controlled at a duty ratio of 100%.
Will saturate and drive current exceeding this will be supplied.
Can not. For this reason, the feedback control calculation
Motor drive signal S calculated by_MIs the motor drive current
The limit has been exceeded and this has led to motor drive signals
S_MControl when the current and the actual motor drive current do not correspond
The object is far from the linear model, and as a result
Appropriate control becomes difficult only with PID control. In particular, an integral operation is included in the feedback control.
Is included, the motor current command value S_ICorrespond to etc.
Control amount is accumulated by the integration operation, but the actual
Even when the motor drive current is saturated.
Instead of accumulating controlled variables by integral calculation
From the motor drive signal S_MExceeds the motor drive current limit
The motor drive signal S_MIs the limit of motor drive current
Excess control amount accumulates corresponding to the amount exceeding
Will be. And later, this accumulated system
The control amount is the motor drive signal S_MOutput when included in
Extra control is performed. That is, the steering wheel
If you try to stop immediately after a sudden rotation of
Generation of steering assist force by excessive control for complicated rotation operation
Continues for an extra time and the steering wheel
Even if you try to stop, assist the rotation operation for a while
A steering assist force in the direction of the steering wheel is generated. Because of this, Steari
Despite trying to stop the towing wheel, this
On the contrary, the motor turns the steering wheel
It will go. As a result, the driver will be
It gives a feeling of strangeness in steering operation such as hanging feeling,
In some cases, you may feel uncomfortable vibration
There is an unsolved problem. [0008] In particular, such a phenomenon affects PID control.
Frequently occur when combining inertia compensation control
No. You can operate the steering wheel more easily
In this case, inertia compensation control is added.
As a control device for electric power steering devices such as
For example, the one described in JP-A-2-290773 is known.
Have been. The outline is shown in FIG. 10.
For the device shown in FIG._MAnd motor
Drive current value i_MAnd the angular acceleration in the rotation of the motor from
Indirectly detected (71), a predetermined gain K
The value (72) obtained by multiplying the motor current command value S_IAdd to
(73) A circuit and the like are added. This inertia supplement
Compensation control to reduce the response delay due to motor inertia.
As a result, the tracking performance in the motor control is improved.
However, based on the angular acceleration of motor rotation, the motor
Current command value S_IBecause additions are made to
Motor current command value S than when only PID control is used_IIs large
More opportunities to be heard. For this reason, motor control
Easy steering operation is possible under normal driving conditions due to improved operability
Function is not possible,
Of steering operation caused by saturation of motor drive current
It is likely to cause a feeling or unpleasant vibration. Accordingly, the present invention provides an unresolved solution of the above conventional example.
Focusing on the issue, the sudden steering operation
Even when the motor drive current is saturated.
Electricity for precise control that does not easily cause discomfort or vibration
Aims to provide control devices for power steering devices
It has been the target. [0010] [MEANS FOR SOLVING THE PROBLEMS] To achieve the above object
The control of the electric power steering apparatus according to claim 1
The device detects the steering torque of the steering system.
Means for generating a steering assist force for the steering system
A motor and at least a torque of the steering torque detecting means
A steering assist force target value is calculated based on the detected value, and the steering assist force target value is calculated.
Performance of feedback control including integral calculation from assisting target value
The steering assist force command value is calculated by the
Control means for outputting a price limit;
Driving means for supplying a driving current to the electric motor.
In the control device of the electric power steering device
The steering assist force command value of the control means is used to drive the electric motor.
Limiting the current to a predetermined range corresponding to the upper and lower limits of the current, etc.
Limiting means for outputting to the driving means, and an output value of the limiting means;
The integration is performed using a correction value based on a difference from the steering assist force command value.
Correction means for correcting the integral amount in the calculation
It is. [0011] The power steering apparatus according to the present invention according to claim 1 is provided.
The control device of the control unit controls the steering assist force command value of the control means.
A predetermined range corresponding to the upper and lower limits of the drive current of the electric motor, etc.
A box for limiting the value is provided. This
In the limiting process by the limiting means, the motor drive current is
Because it simulates the state of saturation at the lower limit, etc.
The steering assist force command value after the limit
It is not possible to exceed the limit value corresponding to the value that can be taken
No. Also, instead of the steering assist force command value before the restriction
The steering assist force command value after the limit processing is output to the drive means,
The steering assist force finger after the restriction process by the driving means
A drive current according to the command value is supplied to the electric motor. this
The steering assist force command value before the restriction
When the motor drive current saturates and cannot follow
However, the steering assist force command value after the restriction
Data drive current can accurately follow. So, after the restriction process
The steering assist force command value and the motor drive current always have a fixed pair.
The response was taken. Further, the apparatus according to the present invention comprises an output of the limiting means.
Correction value based on the difference between the value and the steering assist force command value of the control means
Equipped with correction means for correcting the amount of integration in the integration operation
You. That is, the steering assist force command value after the restriction
Correction of integral amount based on difference from unassisted steering assist force command value
I do. Here, when the motor drive current is not saturated
If it is explained separately when it is saturated,
When the dynamic current is not saturated, that is, the steering assist before the restriction process
If the force command value is within the predetermined range, the steering
The assist command value matches the steering assist force command value before the restriction processing.
Therefore, the correction value at this time is “0”,
No correction of the integration amount in the integration operation by the stage
It is equivalent to Therefore, the motor drive current is not saturated.
The normal feedback control is performed properly,
This allows for precise steering wheel operation.
, A steering assist force that follows the steering wheel is generated. On the other hand, when the motor drive current is saturated,
The steering assist force command value before the rounding limit processing exceeds the predetermined range
When the steering assist force command value after the restriction process is
Since the steering assist force command value of
The correction value is no longer "0", and
The correction of the integral amount in the operation will be effective.
You. Specifically, the steering assist force command value after the restriction processing is
Corresponds to the actual motor drive current
The steering assist force command value after the restriction process and the steering
The correction value based on the difference from the auxiliary force command value
Corresponds to the amount that the auxiliary force command value exceeds the actual motor drive current
I do. Then, in the integration operation corrected by this correction value,
The integral amount is a value that includes the integral operation with respect to the steering assist force target value.
Feedback control is performed normally,
The steering assist force command value before processing exceeds the actual motor drive current
Control amount accumulated in the integration operation
Become. This allows the accumulation of extra control amounts as in the past.
Will not be done. That is, conventionally, the motor drive power
The target steering assist force (motor current
Quotation S_I) For feedback control including integration
As we had done as usual,
The steering assist force command value (the motor drive signal S_M)
However, the extra control amount exceeds the actual motor drive current.
Accumulated by integration
However, in the present invention, the integration amount of the integration operation by the correction means is
The correction compensates for the previously accumulated control amount.
It is offset by a positive value. Therefore, the motor drive current
No extra control is accumulated even when saturated
Therefore, no excessive control is performed. Therefore, the electric power stay according to the present invention is provided.
The control unit of the alling device performed a sharp steering operation
Even when the motor drive current is saturated due to saturation
This makes it possible to perform precise control that hardly causes vibration or vibration. [0015] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electric power steering apparatus according to the present invention will be described.
A first embodiment of the control device will be described with reference to the drawings.
I will tell. FIG. 1 is a schematic configuration diagram thereof. In the figure, 1 is
This steering wheel is a tearing wheel
1 is applied to the input shaft 2a and the output shaft 2b.
Is transmitted to the steering shaft 2 composed of This
One end of the input shaft 2a is connected to the steering wheel 1.
The other end is a torque sensor 3 as steering torque detecting means.
Is connected to one end of the output shaft 2b. And
The steering force transmitted to the output shaft 2b is a universal joy.
And transmitted to the lower shaft 5 via the
To the pinion shaft 7 via the universal joint 6
Is transmitted. The steering force is further transmitted via the steering gear 8.
Then, it is transmitted to the tie rod 9 to steer the steered wheels. S
The tearing gear 8 has a pinion 8a and a rack 8b.
And a pinion 8a
Is converted into linear motion by the rack 8b.
ing. On the output shaft 2b of the steering shaft 2,
Transmits the steering assist force (assist force) to the output shaft 2b
The reduction gear 10 is connected. Also, the reduction gear 10
Is an electromagnetic clutch device 1 for transmitting / disconnecting a steering assist force
1 (hereinafter referred to as a clutch) to provide a steering assist force.
The output shaft of the motor 12 as the generated electric motor is connected
Have been. The clutch 11 is, for example, an electromagnetic type.
The motor 12 is composed of, for example, a DC servomotor.
You. Further, the clutch 11 has a solenoid.
Controller 13 as control means to be described later in the solenoid
The excitation current is supplied by the
10 and the motor 12 are mechanically connected to each other to stop the excitation current.
It is separated by stopping. The torque sensor 3 is a steering wheel
1 to detect the steering torque transmitted to the input shaft 2a.
For example, the steering torque is transmitted to the input shaft 2a.
Torsion angle of the torsion bar inserted between the output shaft 2b
The torsional angular displacement is detected with a potentiometer.
It is configured to issue. And the driver is stearin
Steering operation of the steering wheel 1
According to the magnitude and direction of the twist generated in the shaft 2
It outputs a torque detection signal consisting of an analog voltage. sand
In other words, this torque detection signal is equal to the detected value T of the steering torque._VTo
It is a signal to be a value. The torque sensor 3 is, for example, as shown in FIG.
As shown in the figure, the steering wheel 1 is in the neutral state.
The torque detection value T_VGiven neutral voltage V
₀And turn the steering wheel 1 to the right.
Then, according to the steering torque at that time, the neutral voltage V₀Than
Turning the increasing voltage to the left will increase the steering torque at that time.
Neutral voltage V according to₀To output a decreasing voltage
Has been done. Reference numeral 13 denotes a steering system which drives and controls the motor 12.
Controller that controls the steering assist force to the vehicle
Activated when power is supplied from on-board battery 16
It has been made to be. And the negative electrode of the battery 16
Is grounded, and its positive electrode is an ignition
Control via the switch 14 and the fuse 15a.
Controller 13 and through a fuse 15b.
It is directly connected to the controller 13. This fuse
The power supplied via 15b is, for example, a memory back.
Used for up. Then, the controller 13
The torque detection signal (T_V) And speed
Vehicle speed detection signal V_PAnd the motor 12
Drive control and on / off control of the clutch 11
The output shaft of the motor 12 and the reduction gear 10 are connected / disconnected.
To control. FIG. 2 shows a circuit configuration of the controller 13.
FIG. This controller 13
For example, a control circuit 20, a motor drive circuit 30, a current detection circuit
61, clutch control circuit 62, relay drive circuit 63,
It is composed of a packet relay 64. And control times
The road 20 is connected to a microcomputer 21 (MPU).
A / D converters 22, 23, 24, which constitute the peripheral circuits,
It comprises a phase compensator 25 and a counter 26. This microcomputer 21 has at least
Interface that performs input / output processing with external devices
And a storage unit such as a ROM and a RAM.
I have. The microcomputer 21 uses a phase compensator 25
For example, a phase for stabilizing the control system such as advancing the phase
Torque detection signal from torque sensor 3 that has performed phase compensation
(T_V) Is converted to a digital value via the A / D converter 22
The input torque detection value T is input. Similarly, the current detection circuit
Right direction motor current detection signal I from road 61_RA / D conversion
The rightward motor current detection value i via the converter 24_REnter as
And the left direction motor current detection signal I_LA / D conversion
Motor current detection value i via the converter 23_LEnter as
Power. Further, the vehicle speed detection value V from the counter 26 is input.
Power. The counter 26 is, for example, shown in FIG.
Not installed on the output shaft of the transmission, according to the rotation of the output shaft
Speed sensor 1 such as a rotation speed sensor that generates a pulse signal
Speed detection signal V consisting of a pulse signal from_PAnd enter
The number of pulses per unit time is integrated and the
When the integrated value is read as the vehicle speed detection value V into the data 21
Reset signal R from the microcomputer 21_C
The count value is reset by
You. In the microcomputer 21, these inputs are
The drive current supplied to the motor 12 is determined based on the force signal.
Calculate the signal to be calculated. That is, these input signals
Motor current command value as steering assist force target value based on
S_IIs calculated, for example, PID control (proportional / integral / fine)
Minutes), the mode as the steering assist force command value before the restriction
Data drive signal S_MAnd calculate the saturation of the motor drive current.
By limiting the signal value to a certain range by simulating the sum
Motor drive signal as steering assist force command value after restriction processing
S_{M '}Is calculated. Then, the motor drive signal S_{M '}Based on
Generates a PWM (Pulse Width Modulation) signal
Then, based on the PWM signal, the left pulse width modulation signal PWM
M_L, Right pulse width modulation signal PWM_R, Right direction signal D_R,
Left direction signal D_LGenerate And this is motor driven
Output to the circuit 30. In the microcomputer 21, the starting
When the system is operating, it executes a predetermined failure detection process, and if it is normal,
Control signal S for relay drive circuit 63_RTo
Output as “HIGH” and clutch control circuit
The clutch control signal S gradually increases to 62._CIs output. Ma
Also, at the time of drive control of the motor 12, the current detection circuit 61
Motor current detection value i_RAnd i_LAbnormality monitoring based on
Processing, and when an abnormality is detected, the motor drive circuit 30
Command signal PWM_L, PWM_R, D_R, D_LAnd relay system
Control signal S_RIs output as “LOW” and the
H control signal S_CStop output and turn on the abnormal lamp.
A predetermined process is performed when an error such as an error occurs. The motor drive circuit 30 has at least four
An H-bridge circuit 40 having a switching element of
Gate drive circuits 51 to 51 for driving these switching elements
54. And the H bridge circuit 4
0 is, for example, an enhancement type N-channel MOS
FET4 such as a field-effect transistor (FET)
FETs 41 and 43 connected in series
And FETs 42 and 44 are connected in series.
These series circuits are connected in parallel and the battery 16
Through a fail relay 64. And F
Connection between ET41 and 43 and FET42 and 44
The motor 12 is connected to the point. Also, FET
43 has a right-side current detection resistor R_RThrough the ground
Similarly, the source side of the FET 44 detects the leftward current.
Resistance R_LGrounded. The gates of the FETs 41 to 44 are
G terminal₁~ G_FourIs the corresponding gate drive circuit
51 to 54, and from the gate drive circuits 51 to 54
When a predetermined voltage is supplied, the FETs 41 to 44 are turned off.
The FETs 42 and 43
When only one is turned on, the FET 42 and the motor 1
2, FET43, right direction current detection resistor R_REnergized in the direction of
Then, the motor 12 rotates forward and the FETs 41 and 44
When only the switch is turned on, the FET 41, the motor 12,
FET44, leftward current detection resistor R_LEnergized in the direction of
Thus, the motor 12 rotates in the reverse direction. On the other hand, the current detection circuit 61
Direction current detection resistor R_RAnd leftward current detection resistor R_LBoth ends of
Amplifies the voltage generated at the motor
Current detection signal I_RAnd leftward motor current detection signal I_LWhen
And outputs it to the control circuit 20. Also, clutch control circuit
62 is a clutch control signal S from the control circuit 20._CIn response
The excitation current i_CTo generate the solenoid of the clutch 11
And the output shaft of the motor 12 and the reduction gear 10 are mechanically connected.
Control to the coupled / disconnected state. Then, the relay driving circuit 63
Output signal S of computer 21_RBased on ferry
On / off control of the ray 64 is performed. This failure
The relay 64 is a relay switch having normally open contacts.
The power supply of the battery 16 to the H-bridge circuit 40 is
ON / OFF control is performed. Next, the microcontroller
Processing procedure of drive control processing of motor 12 in computer 21
Will be described based on the flowchart shown in FIG. this
The motor drive control process is performed at a preset time interval.
This is performed by a timer interrupt, for example, every few msec.
Be executed. Note that the microcomputer 21
When the ignition switch 14 is turned on,
Performs fixed failure detection processing, and when no abnormality is detected
Is the relay control signal S_RIs output as "HIGH"
You. In response, the relay drive circuit 63
-64 coil is energized.
The ray 64 is closed and the H-bridge circuit 40 is energized.
Is performed. Also, the clutch control signal S which gradually increases_CClick
Output to the latch control circuit 62. As a result, the clutch 1
1 operates to move the rotation shaft of the motor 12 and the reduction gear 10
Gradually establish a mechanical connection. In addition, each gate drive
"LOW" when starting each command signal to the circuits 51 to 54
Is output as Also, for example, the ignition switch 1
When 4 is turned off, a preset end time
Execute the predetermined processing of, for example, stored in the steering system
Proportional to motor angular velocity to absorb the elastic energy
Clutch control signal S_CTo the clutch control circuit 62.
Control to apply viscous load for a predetermined time.
Have been snarling. Then, the ignition switch 14 is turned off.
When the specified failure detection process ends and the
The computer 21 performs the following motor drive control processing.
Execute. In this process, first, in step S1, A /
Phase compensation is performed by the phase compensator 25 via the D converter 22.
The detected torque value T from the torque sensor 3 is read.
Further, the process proceeds to step S2, where T = T−V₀Naru performance
Calculation to turn off the neutral torque detection value T to zero.
Perform set processing. Next, the process proceeds to step S3, where the counter
26, that is, the vehicle speed detection value V is read.
The reset signal R_COutput and count
Reset the default value. Then, the process proceeds to step S4,
FIG. 6 shows the correspondence between the steering torque, the vehicle speed, and the motor current.
For example, referring to the characteristic diagram shown in FIG.
The motor current corresponding to the detected value V is searched, and this is
Current command value S_ISet as This characteristic diagram shows that the steering shaft 2
The auxiliary steering force corresponding to the steering torque input to
Needed to drive motor 12 to generate 12
The relationship between motor current, steering torque, and vehicle speed is shown.
The motor current command decreases as the vehicle speed decreases.
The larger the value, and the larger the steering torque,
The current command value increases and exceeds a certain value.
Is set not to be large. Then, the flow shifts to step S5, where the motor
Flow command value S_IIs differentiated and a predetermined proportional gain
Is multiplied by the differential processing value f_DAnd Next,
In step S6, the rightward motor current detection value i_RAnd left
Motor current detection value i_LLoad the right direction motor current
Detection value i_RIs a positive value, and the motor current detection value i in the left direction is_LTo
Set as a negative value and determine the motor power from the sum of these detection signals.
Flow detection value i_MIs calculated. That is, i_M= I_R−i_L
It is calculated by: Here, in the current detection circuit 61, the
Motor current detection signal I_RAnd I_LThe effective value of
And perform sufficient filtering on each signal.
It is assumed that In step S7 following this,
Is, for example, an abnormality monitor as shown in the flowchart of FIG.
Perform visual processing. The details of the abnormality monitoring process will be described later.
Will be described. Next, the process proceeds to step S8,
Motor current command value S set in S4_IAnd in step S6
Calculated motor current detection value i_M, Ie, e_M
= S_I−i_MGives the current deviation e_MIs calculated. The following
In step S9, the current deviation e_MMultiplied by a predetermined proportional gain
And calculate the proportional processing value f_PAnd Next step S10
Now, the model calculated and stored in the immediately preceding processing cycle
Data drive signal S_MAnd also calculated in the immediately preceding processing cycle
And stored motor drive signal S_{M '}And from these
The difference dS in the equation dS = S_{M '}-S_MIt is calculated by: Soshi
Then, in the following step S11, a predetermined value of the gain K_C
And the correction value K_CX dS is calculated. This allows
Data drive signal S_{M '}And motor drive signal S_MBased on the difference
A correction value is determined. Note that the gain K_CValue is simply
Data drive signal S_{M '}Is corrected by the amount exceeding the specified range
From the point of view, "1" may be used, but the response of the system is actually
Control system dynamic characteristics and non-linear
Determined analytically and experimentally taking into account the shape etc.
It is set to a value equal to or less than “1”. Further, in the next step S12, the integral
Input value f_{P '}To the proportional processing value f_PAnd correction value K_C× dS and
From equation f_{P '}= F_P+ K_C× dS. Soshi
Then, in the following step S13, the value f_{P '}For the integration process
And multiplies it by a predetermined proportional gain to obtain an integral processing value f_I
And Then, in step S14, the differential processing value f
_DAnd the proportional processing value f_PAnd the integral processing value f_IAnd
This is represented by the motor drive signal S_MAnd This motor drive signal
S_MIs the new value from this processing cycle.
You. Next, the process proceeds to step S15, where
Is a new motor drive signal S_MIs the upper limit S_MAXThan
When it is larger, the motor drive signal S_{M '}As the upper limit value S
_MAXAnd the motor drive signal S_MIs lower limit value -S
_MAXAbove and upper limit S_MAXMotor drive when
Signal S_{M '}Motor drive signal S as the value of_MThe value of
Motor drive signal S_MIs lower limit value -S_MAXLess than
The motor drive signal S_{M '}Lower limit value -S_MAXTo
adopt. Here, the upper limit S_MAXIs the right pulse width modulated signal
No. PWM_RWhen the duty ratio becomes 100%
Drive signal S_MAnd the lower limit value -S_MAXIs the left pulse
Width modulation signal PWM_LWhen the duty ratio becomes 100%
Motor drive signal S_MIs the value of That is, the upper limit S
_MAXAnd lower limit -S_MAXIs the drive current of the electric motor 12
This is a value corresponding to the upper and lower limits. So, in this step
The calculation in this case is based on the upper and lower limits of the drive current of the electric motor 12.
This is processing to limit the value to the corresponding predetermined range, and this
Therefore, the motor drive signal S_MFrom the motor drive signal S_{M '}Is calculated
Will be issued. This motor drive signal S_{M '}Indicates that the PWM signal is
Duty ratio is 100% and the motor drive current is saturated
Even at that time, the motor drive current
You. Then, in step S16, the module
Data drive signal S_{M '}Is S_{M '}It is determined whether or not ≧ 0, and S
_{M '}If ≧ 0, the steering wheel 1 is turned to the right.
The process proceeds to step S17 assuming that the vehicle has been steered. Soshi
In step S17, the rotation direction of the motor 12 is
Right direction signal D to be set for reverse direction_RTo “HIGH”,
Also, the motor drive signal S_{M '}Drive current according to the motor 1
2 Set the duty ratio to supply to
Width modulation signal PWM_RAs the corresponding gate drive
Output to the driving circuits 52 and 53 and the gate driving circuits 51 and 54
Has left pulse width modulation signal PWM_LAnd left direction signal D_LTo
Output as "LOW". And this processing cycle
And returns to the calling program. On the other hand, in step S16, S_{M '}Is not ≧ 0
When the steering wheel 1 is steered to the left,
It is determined that there is, and the process proceeds to step S18. Soshi
In step 18, the rotation direction of the motor 12 is reversed.
Left direction signal D to set in direction_LTo “HIGH” and
The motor drive signal S_{M '}Drive current according to the motor 12
Set the duty ratio to supply to the left pulse
Width modulation signal PWM_LAs the corresponding gate drive
The signals are output to the driving circuits 51 and 54. Also, the right direction signal D_RPassing
And right pulse width modulation signal PWM_RIs "LOW"
Output to the gate drive circuits 51 and 54, respectively. And
The processing ends, and the program returns to the calling program. like this
In steps S17 and S18, the motor drive signal S_{M '}To
A PWM signal is generated based on the PWM signal. That is, step
The processing in S17 and S18 constitutes a part of the driving means.
As a result, the motor drive signal S_MNot a motor drive
Motion signal S_{M '}Is supplied to the electric motor 12 according to the
It is. Note that these motor drive signals S_MAnd motor drive
Signal S_{M '}Is used to calculate the correction value in the next processing cycle.
The value is saved. Then, one of the motor drive control processes
The processing cycle ends. The abnormality monitoring process in step S7 will be described.
I will tell. In this process, as shown in FIG.
In step S21, the motor current detection value i_MThe absolute value of is the maximum current
Value I_MAXIt is determined whether it is smaller than. Where the maximum
Flow value I_MAXIndicates that the motor drive circuit 30 is operating normally.
This value is set in advance as a value that is considered to be considered. Soshi
And the motor current detection value i_MIs the maximum current value I_MAX
If the value is smaller than
And returns to the calling program. On the other hand, in step S21, the motor current is detected.
Value i_MIs the maximum current value I_MAXMust be smaller than
At this time, an excessive current is flowing through the H-bridge circuit 40,
It is determined that an abnormality has occurred, and the process proceeds to step S22.
You. In Step S22, the gate drive circuits 51 to 54
Each command signal PWM_L, PWM_R, D_R, D_LTo “LO
W ", and thereby the H-bridge circuit 40
Cut off the current path. Then, the process proceeds to step S23,
Clutch control signal S to clutch control circuit 62_COutput
By stopping the clutch, the clutch 11 is operated to
The output shaft of the motor 12 and the reduction gear 10 are separated.
Further, the process proceeds to step S24, where the relay driving circuit 6
3 to the relay control signal S_RIs output as “LOW”
By operating the fail relay 64,
Cut off the power supply from the battery 16 to the H-bridge circuit 40.
You. Then, in step S25, for example, the main processing
Notifies abnormalities to higher-level programs such as programs and processes
To end. After that, in the upper-level program
Does not execute the motor drive control process. The electric drive of the first embodiment having such a configuration
The operation of the control device of the water steering device
explain. Specifically, if the vehicle is running straight after starting
The driver suddenly turns the steering wheel right when
And then immediately replace the steering wheel.
The operation when the steering operation is performed will be described. Note that this
The state of the state change when such an operation is performed is shown on the time axis t.
The horizontal axis is shown in FIG. In the figure, θ in FIG.
Indicates the steering angle of the tearing wheel.
S indicated by line_IIs the motor current command value S_IAnd (c)
I indicated by a solid line_{M '}Is the motor current detection
Output value, i shown by a solid line in (d)._MOf the present invention
Motor current detection value i in the embodiment_MIt is. further,
(B), (c) and (d) show the broken line i_{M *}Is
Motor drive current is ± i_MAXWithout any saturation
Virtual motor power detected when it can be supplied
This is the flow detection value. Now, assume that the vehicle is in a stopped state.
In this state, the ignition switch 14 is turned on.
Assuming that the microcomputer 21
Performs a predetermined failure monitoring process, and if there is no abnormality,
ー Control signal S_RTo “HIGH”, the relay drive circuit 6
3 and the clutch to the clutch control circuit 62.
Control signal S_CIs output. This allows the relay
The drive circuit 63 supplies current to the coil of the fail relay 64
Is performed, the failure relay 64 is closed.
The power supply of the battery 16 is supplied to the H-bridge circuit 40.
Will be able to pay. Also, the clutch 11 operates gradually,
The rotation shaft of the motor 12 and the reduction gear 10 are in a mechanically coupled state.
The rotational driving force of the motor 12 is
2 can be transmitted. Then, in the microcomputer 21,
After initializing variables and data areas, etc.,
The motor drive control process is executed only in the cycle. At this time,
Assuming that the operator does not perform steering operation,
Torque detection signal T from_VIs the neutral voltage V₀Becomes
At this time, since the vehicle is stopped, the vehicle speed detection value V is zero.
Therefore, in the motor drive control process of FIG.
Is the motor current command value S from the characteristic diagram of FIG._IIs almost zero
And the motor drive signal S_M, Motor drive signal S_{M '}
Is also substantially zero, and the motor current detection value i_MAlso almost zero
Therefore, the motor 12 is not driven. And stop
The vehicle moves from a running state to a running state, but the vehicle is running straight.
That is, while the steering angle θ of the steering wheel is “0”
Means that the torque detection value T from the normal torque sensor 3 is in the neutral position.
Place V₀Near the motor current command
Value S_I, Motor drive signal S_M, Motor drive signal S_{M '},
Data current detection value i_MBecomes substantially zero, and the motor 12
It is not driven (see time t0 in FIG. 7). During this traveling, for example, the occupant suddenly steers to the right.
If the operation has been performed (see time t1 in FIG. 7), the operation
As the steering angle θ increases in the positive direction, the torque sensor 3
Torque detection signal T_VIs the neutral voltage V₀Voltage greater than
Value. Processing cycle of motor drive control processing at this time
In detail, the microcomputer 21
Is the torque detection value T input via the A / D converter 22.
T = T−V based on₀Offset processing, and neutral point
Is calculated as the torque detection value T that makes the value zero. In addition,
6 based on the detected torque value T and the detected vehicle speed value V.
From the corresponding motor current command value S_ISet. This and
Right steering was performed, the torque
The output value T is a positive value, and therefore, the motor current command value S
_IIs also a positive value. At this time, for example, when the vehicle is traveling at a low speed.
If the steering torque is large in the
Motor power command value S_IIs set large
When driving at high speed, the steering wheel
A small steering assist force is generated so that
Motor current command value S_IIs set to a small value
You. Similarly, when the steering torque is small,
The smaller the value, the larger the motor current command value S_ISet the vehicle speed
Response of the steering wheel 1 as
Small motor current command value S_ISet to
You. In any case, if a sudden steering operation is performed,
With the sudden increase of the steering torque, the motor current command value S
_IIs a positive value. However, at this point the motor is still
It is not assumed that the drive current is saturated. You
That is, the motor drive signal S_MIs lower limit value -S_MAXAnd on
Limit value S_MAXBetween. Then, the set motor current command value S_ITo
A predetermined process such as a differential process is performed on the differential gain K_D
And the differential processing value f_DIs calculated. Also, left and right direction
Motor current detection value i_RAnd i_LBased on i_M= I_R
−i_LAs a result, the current value of the motor 12
Current detection value i_MIs calculated. Then, execute the abnormality monitoring process.
The motor current command value S_IWhen
This motor current detection value i_MAnd the current deviation e from_MCalculate
You. And this current deviation e_MAnd the proportional gain read out
K_PAnd the proportional processing value f_PIs calculated. Further, calculated in the immediately preceding processing cycle,
Motor drive signal S_MAnd motor drive signal S_{M '}And from the formula
dS = S_{M '}-S_MTo calculate the difference dS,
Gain K_CAnd the correction value K_CX dS is calculated. Mo
At this time, the motor drive current is not yet saturated
Therefore, the motor drive signal S_MAnd motor drive signal S_{M '}Is a value
And the difference dS and the correction value K_C× dS is “0”
It is. Next, the proportional processing value f_PAnd correction value K_C× dS
From equation f_{P '}= F_P+ K_CInput of integral operation by xdS
Value f_{P '}And calculate the value f_{P '}Performs integration on
A predetermined proportional gain is multiplied to obtain an integral processing value f_IToss
You. At the time of this processing cycle, the correction value K_C× dS
Since it is “0”, the input value f of the integration operation_{P '}Is the proportional processing value
f_PMatches. Then, the input value f_{P '}Integrated for
Integral gain K_IAnd the integral processing value f_ICalculate
And these differential processing values f_DAnd proportional processing value f_PAnd integration
Value f_IAnd the motor drive signal S_MIs calculated. This
When the input value f_{P '}Is the proportional processing value f_PThat matches
From the motor drive signal S_MIs the same as the value without correction.
Match. Next, the value is set to the lower limit value -S_MAXAnd the upper limit S_MAX
And the motor drive signal S_MFrom
Motor drive signal S_{M '}Is calculated.
No. S_MIs lower limit value -S_MAXAnd the upper limit S_MAXBetween
Therefore, the motor drive signal S_{M '}Is the motor drive signal S_M
Matches. Therefore, the motor drive signal S_{M '}Is a motor drive
Motor drive signal S when dynamic current is not saturated_MAnd
It matches the one without any correction. Then, the motor drive signal S_{M '}Based on the sign of
Current direction is determined, and in this case, the motor drive signal S_{M '}≧
0, the command signal PWM_LAnd D_LIs “LO
W "and output the command signal D_RIs "HIGH", command
Signal PWM_RIs the motor drive signal S_{M '}Duty according to
Output as a pulse signal of ratio D. In response, the game
The drive circuit 53 supplies a predetermined voltage to drive the FET 43
To the ON state, and the command signal PWM_RIs "HIGH"
, The gate drive circuit 52 supplies a predetermined voltage
Thus, the FET 42 is on / off controlled. At this time, the command signal PWM_LAnd D_LBut
Since it is “LOW”, the gate drive circuits 51 and 54
Does not supply a predetermined voltage to the FETs 41 and 44
Thus, the FETs 41 and 44 remain off. There
When the FET 42 is turned on, the battery 16
Power supply, the FET 42, the motor 12, the FET
43, right direction current detection resistor R_RPower in the direction of
The motor 12 rotates forward and the FET 42 is turned on / off.
And the motor drive signal S_{M '}Drive current is supplied according to
Then, drive control of the motor 12 is performed. As described above, in this processing cycle, the steering
When the steering angle θ of the ring wheel changes in the positive direction, etc.
Accordingly, the motor current command value S_IBecomes a positive value, and
Motor drive signal S_{M '}Also takes a positive value. And respond to this
The detected value of the drive current, that is, the detected value of the motor current i_M
Also the motor current command value S_IIncreases in the positive direction slightly after
You. That is, the delay according to the electric responsiveness of the motor 12
Is the motor current detection value i_MIs the motor current command value S_I
(See FIG. 7B). At this time, I mentioned above
Motor drive signal when the motor drive current is not saturated
S_MMotor drive signal for
No. S_{M '}Are the same, the motor current detection value i_MAnd
And motor current detection value i_{M '}Both, motor drive current is saturated
Motor current detection value i when not assumed_{M *}Matches
You. Therefore, the motor control state at this time
Is the same as the control for the operating state that can be approximated by a linear model.
Condition and proper condition. And such control
The steering cycle is repeated several times before the steering
With the sudden increase of the angle θ, the torque detection value V and the motor
Current command value S_IIncreases, the motor drive signal S_Mof
The value is the upper limit S_MAX(See FIG. 7).
Time t2). Thus, the motor drive signal S_M
Is the upper limit S_MAX(Time t2 in FIG. 7)
In the processing cycle from (see part to time t3),
From the reading of the torque detection value T to the motor current command value S_ISetting
Constant, motor current detection value i_MAnd current deviation e_MCalculation, and
To the proportional processing value f_PUp to the calculation of
However, for other processing, the correction is effective.
Different. That is, the equation dS = S_{M '}-S_MThe difference
Calculated, and the correction value K_CX dS is calculated, and
The motor drive signal S_MIs the upper limit S_MAXBeyond
S_{M '}> S_MTherefore, the difference dS and the correction value K_C
XdS is a negative value. And the formula f_{P '}= F_P+ K_C×
Input value f of integral operation calculated by dS_{P '}Is the traditional
Input value f for integration operation_PIt becomes a value smaller than. Therefore,
In this processing cycle, integration is performed by integration operation.
The integrated amount (see step S13 in FIG. 3) is
Compare (S_M-S_{M '}Only) less. That is, motor drive
Signal S_MIs the upper limit S_MAXMore than the previous one
Less. As a result, the integration in the integration operation
The amount reflects the saturation state of the motor drive current.
You. Then, the integration processing value f_I, A new motor drive
Motion signal S_M, Motor drive signal S_{M '}Is calculated. This and
The motor drive signal S_MIs the upper limit S_MAXBeyond
Therefore, the motor drive signal S_{M '}Is the upper limit S_MAXLimited to
Is done. That is, the PWM signal has a duty ratio of 100%.
And the drive current of the motor is saturated. Therefore,
Motor current detection value i at this time_MIs the motor current detection value
i_{M *}And the upper limit i_MAXIs almost constant
It becomes Note that the motor current detection value
i_{M '}Is the upper limit i_MAXIs almost constant. Therefore, the motor control state at this time
Is controlled so that the motor drive current can be supplied to the maximum
This is an appropriate output state in that it is controlled. Also,
Nonlinear model-based correction for motor drive current saturation
Integral calculation taking into account the
The sum state is reflected in the integration amount. This point is just
Motor drive current saturation because
This is different from the conventional control in which the state is not reflected in the integral amount. What is the processing cycle in such a control state?
After the driver has repeated the steering wheel several times,
If you make a left turn to return the eel,
Therefore, the steering angle θ decreases. And the steering angle
As the θ decreases, the torque detection value V and the motor current command
Value S_IAlso decreases, and eventually the motor drive signal S_Mof
The value is the upper limit S_MAX(See FIG. 7).
At time t3). Up to this point,
As described above, the motor current detection value i_MIs the motor current detection value i_{M '}
And the upper limit i_MAXIs almost constant,
The control state of the motor also externally matches the conventional state. However
When comparing the amount of integration in the integration operation,
Is the virtual motor current detection value i_{M *}The quantity corresponding to is integrated
And the actual motor current detection value i_{M '}Extra than the amount corresponding to
Although a large amount was integrated (Fig. 7 (c)
In the device of the present invention, the actual motor current
Detection value i_MOnly the quantity corresponding to is integrated. Thus, the motor drive signal S_MIs the upper limit
S_MAX(After time t3 in FIG. 7)
In the processing cycle (see later section), the steering angle
With the decrease, the torque detection value V also decreases rapidly,
Motor current command value S calculated based on_IAlso decrease quickly
Will come. Then, the motor current is detected according to the procedure described above.
Value i_M, Current deviation e_MCalculation, proportional processing value f_PEtc.
Motor drive signal S_MAnd motor drive signal S_{M '}Also calculate
In this case, the motor drive signal S_MIs the lower limit
Value-S_MAXAnd the upper limit S_MAXBetween the
Data drive signal S_{M '}Is the motor drive signal S_MMatches. sand
That is, the motor drive signal S_{M '}Indicates that the motor drive current is saturated
Motor drive signal S when not present_MMatches. And
Input value f of integral operation in feedback control_{P '}About
The correction is substantially stopped. Moreover, the previous correction
The amount of integration in the integration operation performed up to this point is
As described above, it corresponds to the actual motor drive current.
Therefore, the amount of integration at this time is
Motor drive power in Dell-based feedback control
It is almost equal to the integral when the flow is not saturated. That is,
The effect of saturation of the motor drive current is no longer
It does not remain in the control state in the feedback control. Therefore, the motor drive signal S_{M '}Is a motor drive
Motor drive signal assuming that the dynamic current does not saturate
It matches the one without any correction. And this mod
Data drive signal S_{M '}Resulting motor current controlled by
Detection value i_MAssumed that the motor drive current did not saturate
Motor current detection value i_{M *}And almost match
(See FIG. 7D). Therefore, the motor at this time
The control state is based on the operating state that can be approximated by a linear model.
This is the same as the control, and is in an appropriate state. Incidentally, comparing this point with the conventional example,
, The motor current command value S_IDecreases and based on this
Proportional processing value f_PFeedback
An extra amount remains in the integral amount in the integral operation in control.
The integration processing value f_IStill maintain a large value
Therefore, the motor drive signal S_MAlso keep the large value
One. Then take some time to release the extra integration
For the first time after the exit has ended (time in FIG. 7 (c)
T4), motor drive signal S_MIs the value S_MAXLess than
It becomes. Therefore, the motor current detection value i_{M '}Is a motor drive
Motor current detection value assuming that the dynamic current does not saturate
i_{M *}In contrast, it decreases with a delay. Furthermore, this
When a delay like the above causes excessive control in the opposite direction
(See time t5 in FIG. 7C). this
On the other hand, the device of the present invention
There is no delay. In the apparatus of this embodiment,
The motor drive control process is repeated several times.
The driver returns the steering wheel to
When stopped, the motor drive signal S_{M '}Becomes almost zero,
As a result, the motor current detection value i_MQuickly becomes almost zero
(See time t6 in FIG. 7). And this thing
Is the motor drive signal S_MDevice with a delay in the change of
Than the time when the same state is reached (time t in FIG. 7).
(See section 7), achieved earlier. Therefore, the device of this embodiment is
The driver suddenly turns the steering wheel to the right during
Steering that returns the steering wheel immediately after
Even when performing operations, steering wheel operation
Control to generate a steering assist force that accurately follows
I can. Electric power steering device of the present invention
A second embodiment of the control device will be described. this
Has added motor inertia compensation control to PID control.
FIG. 8 shows a schematic configuration diagram thereof. This
Is based on the detected torque value T and the detected vehicle speed value V.
Motor drive signal S_{M '}Calculation control circuit 2100 for calculating
And the motor drive signal S_{M '}Pal with duty ratio corresponding to
Signal PWM_*, D_*A PWM circuit 29 that generates
PWM such as pulse signal_*, D_*Drive current according to the
Motor driving circuit 30 for supplying the motor 12
The current value of the drive current by the circuit 30 was detected and detected.
Current value i_MThat feeds back to the PID control circuit
And a detection circuit 61. Here, the arithmetic and control circuit 2100 calculates the torque
Motor drive current based on detected value T and vehicle speed detected value V
Motor current command value S as a command value for value setting, etc._I
Command calculator 18 for generating the motor current command value S
_{I '}Motor drive signal by PID control with
S_MAdder 19a constituting a PID control circuit for generating
, Differential calculator 19b, proportional calculator 19c, and integration calculator 1
9d, an adder 19e, and a motor drive signal S_MSignal value
± S_MAXMotor drive signal S_{M '}Output
Limiter 2110, adder 2121 and proportional calculator 2
Correction circuit 212 composed of 122 and adder 2123
0. This part is the same as that of the first embodiment.
This is an electronic circuit substantially corresponding to the Ecron computer 21. Further, the arithmetic and control circuit 2100 includes a motor
Drive signal S_{M '}And motor drive current value i_MAnd from the motor rotation
Angular acceleration detector for indirectly detecting angular acceleration in rolling
71 and a predetermined inertia compensation coefficient K_GMultiply by
Inertia compensation coefficient circuit 72 for calculating a compensation value;
Is the motor current command value S_ITo the motor current command value S
_{I '}And an adder 73. This allows the motor
Inertial compensation control is also performed to compensate for the response delay due to inertia.
You. The inertia compensation control will be described in detail.
Motor angular acceleration ω at the acceleration detector 71₁The calculation of
Is done as follows. Motor drive signal S_{M '}Pulse corresponding to
Duty ratio D of width modulation signal PWM, power supply voltage V
_BAT(= Battery voltage B), supply to motor 12
The average voltage V is expressed as follows. V_AV= DV_BAT  … (1) On the other hand, when the motor 12 rotates, the rotation
In 12, a back electromotive force is generated.
The angular velocity at₀And the back electromotive force constant is k_T
Then, the back electromotive voltage generated in the motor 12 is k_T・ Ω₀
It becomes. From this, the motor 1 having the coil resistance R
2 average voltage V supplied to_AVIs also expressed as: V_AV= K_T・ Ω₀+ Ri (2) Therefore, from equations (1) and (2), V_AVTo erase
TA angular velocity ω₀Is determined as follows. ω₀= (DV_BAT-Ri) / k_T  … (3) Further, differentiating both sides of this equation (3) with time t
From the angular acceleration ω₁Is calculated. The angular acceleration ω thus detected indirectly₁
Is a predetermined inertia compensation coefficient K in the inertia compensation coefficient circuit 72._GAnd the power
And the motor current command value S_IThe compensation value for
Can be The compensation value is the motor current command value S_ITo
The motor current command value S is added by the adder 73._{I '}Sought
It is. As a result, inertia compensation control is performed and motor inertia is controlled.
The delay of the response of the motor due to the characteristics is compensated. Note that the angular acceleration ω₁Is detected directly by the sensor
And, for example, an angle sensor attached to the motor shaft.
First, the angle value detected by the sensor is differentiated with respect to time t.
Angular velocity ω₀, And differentiate it again to calculate the angular acceleration ω₁
May be obtained. Or, for example, Steari
Steering by the angle sensor attached to the shaft 2
The steering angle of the steering wheel is detected and this is used to determine the angle of the motor shaft.
By using an approximate value, the angular acceleration ω₁Asking for
Is also good. In addition to the inertia compensation control, not shown,
Improving vehicle stability by applying electric viscous resistance to the steering system
The angular velocity ω₀Given damper coefficient K_VMultiply by
This multiplied value is used as the motor current command value S_IDamper to subtract from
Control may be performed. The electric power steering having the above configuration
The operation of the control device of the apparatus is based on the motor current command value S_ITo inertia
The motor current command value S is compensated by the compensation control._{I '}Seeking
Of the first embodiment, except that the process of
It is almost the same as Therefore, duplicate explanations are omitted.
However, in the second embodiment, the motor current command value S
_IIs the same because compensation values are added to
Even in the operation related to the steering operation, in the first embodiment,
Motor current command value S_IMotor current command value S_{I '}But
Tends to be larger. For this reason, the driver
Suddenly turns the steering wheel right and then
Performed steering operation to return the tearing wheel to its original position.
At times, the motor current command value S_{I '}Is shown in FIG.
S_IIt becomes steeper and has a higher peak value than
Motor current detection value i_{M *}Is the upper limit i_MAXArea beyond
It is wider than the area Y in FIG. Or
If the inertia compensation control is not performed, the motor current detection value i_{M *}Is on
Limit value i_MAXMotor for steering operation that does not exceed
Current detection value i_{M *}Is the upper limit i_MAXCan exceed
You. However, in this device, the correction by the correction circuit 2120
Even in such a case, the feed is
The integration amount in the back control integration calculator 19d is
It corresponds to the motor drive current. And virtual
Motor current detection value i_{M *}Is the upper limit i_MAXShould fit below
Actual motor current detection value i quickly with timing_MAlso upper limit
Value i_MAXFits below. So, the feeling of strangeness in steering operation and
Operate the steering wheel without causing unpleasant vibrations
To generate a steering assist force that accurately follows the work
Can be. Therefore, this device can be used in addition to PID control.
Sudden steering while performing inertia compensation control
Saturation of motor drive current even when operation is performed
Perform accurate control that does not easily cause discomfort or vibration due to
It can be. In each of the above embodiments, the right
The case where steering was performed was explained, but left steering was performed.
Even in this case, the same effect as described above can be obtained. In the above embodiment, PID control is used.
The case where the motor drive control is performed by
Not limited to this, for example, control by PI control etc.
It is possible. In the above embodiment, the steering torque and the vehicle speed
When setting the motor current command value based on
Has been described, for example, based only on the steering torque
It is also possible to set the motor current command value by using the following method. Further, in the above embodiment, the FET (field effect
Motor drive circuit with transistors
The case has been described, but the invention is not limited to this.
Apply other switching elements such as transistors
It is also possible. [0075] As described above, according to the first aspect of the present invention,
In the control device of the power steering device of the invention,
The motor drive current is limited by upper and lower limit values
Simulate the state of saturation. Also, a correction means is provided,
Correct the integral amount in the minute operation. This allows the motor
Extra control as before even when the drive current is saturated
No accumulation of volume is performed, and no excessive control is performed. Therefore, if a sudden steering operation is performed,
Even when the motor drive current is saturated,
Electric power stage that can perform precise control with less vibration
A control device for the ringing device can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention. FIG. 2 is a block diagram of a circuit configuration centering on a controller. FIG. 3 is a flowchart showing a procedure of a motor drive control process by a microcomputer. FIG. 4 is a flowchart showing a processing procedure in an abnormality monitoring processing for a motor drive control processing by the microcomputer. FIG. 5 is a characteristic diagram illustrating a relationship between a steering torque and an output voltage of a torque sensor. FIG. 6 is a characteristic diagram showing a relationship between a steering torque and a motor current value using a vehicle speed as a parameter. FIG. 7 is a signal waveform diagram for explaining the operation of the device of the present invention. FIG. 8 is a block diagram showing another embodiment of the present invention. FIG. 9 is a block diagram of a conventional device. FIG. 10 is a block diagram of another conventional device. [Description of Signs] 1 Steering wheel 2 Steering shaft 3 Torque sensor 4 Universal joint 5 Lower shaft 7 Pinion shaft 8 Steering gear 9 Tie rod 10 Reduction gear 11 Clutch 12 Motor 13 Controller 14 Ignition switches 15a, 15b Fuse 16 Battery 17 Vehicle speed sensor 18 Current command calculator 19 PID control circuit 19a Adder 19b Differential calculator 19c Proportional calculator 19d Integral calculator 19e Adder 20 Control circuit 21 Microcomputer (MPU) 22, 23, 24 A / D converter 25 Phase compensator 26 Counter 29 PWM circuit 30 Motor drive circuit 40 H-bridge circuit 41-44 FET (field effect transistor) 51-54 Gate drive circuit 61 Current detection circuit 62 Clutch control circuit 3 relay driving circuit 64 fail relay 71 angular acceleration detector 72 inertia compensation coefficient circuit 73 an adder 2100 arithmetic control circuit 2110 limiter 2120 correction circuit 2121 adder 2122 proportional calculator 2123 adder

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-290773 (JP, A) JP-A-5-301576 (JP, A) JP-A-5-301575 (JP, A) JP-A-4-301 71959 (JP, A) JP-A-5-219769 (JP, A) JP-A-3-3004 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B62D 5/04 B62D 6 / 00-6/06

Claims (1)

(57) [Claim 1] A steering torque detecting means for detecting a steering torque of a steering system, an electric motor for generating a steering assist force for the steering system, and at least the steering torque detecting means A steering assist force target value is calculated based on the detected torque value, and a steering assist force command value is calculated from the steering assist force target value by a feedback control calculation including an integral calculation, and the steering assist force command value is output. A control device for an electric power steering apparatus, comprising: a control unit; and a driving unit that supplies a drive current according to an output of the control unit to the electric motor, wherein a steering assist force command value of the control unit is controlled by the electric motor. Limiting means for limiting the drive current to a predetermined range corresponding to the upper and lower limit values of the drive current and outputting to the drive means; and a correction value based on a difference between an output value of the limit means and the steering assist force command value. Control device for an electric power steering apparatus characterized by comprising a correction means for correcting the integrated amount of the integral calculation.