JPH08216910A - Steering controller of vehicle - Google Patents

Abstract

PURPOSE: To surely stop the supply of a drive current to a motor when a volt age of a battery drops under the specified voltage, in the steering controller of a vehicle. CONSTITUTION: The steering angle of a steering wheel WL is controlled by operating steering angle difference of the objective steering angle of the steering wheel WL set with an objective steering angle setting means DS and the actual angle of the steering wheel WL measured with a steering angle measuring means AS, and controlling the drive current of a motor MT by means of a steering angle control means AC, according to this steering angle difference. On the other hand, a voltage determination means VS compares the voltage of a battery BT with specified voltage, and when it determines that it has downed under the specified voltage, an objective steering angle compensating means DC sets the actual steering angle as the objective steering angle. Hereby, the difference of steering angle becomes zero, and this stops the supply to a drive current to the motor MT. Furthermore, this is provided with an objective angle change rate adjusting means RC, and the steering angle is recovered gradually at the time of reopening of the drive of the motor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering control device, and more particularly to a front wheel steering device for correcting the steering angle of the front wheels of a four-wheel vehicle and a rear wheel steering device for adjusting the steering angle of the rear wheels. Related to a simple steering control device.

[0002]

2. Description of the Related Art Conventionally, there are known front wheel steering devices for correcting the steering angles of front wheels of four-wheeled vehicles and rear wheel steering devices for adjusting the steering angles of rear wheels. With respect to this rear wheel steering system, for example, in Japanese Patent Laid-Open No. 6-144258, when the battery voltage drops, the magnitude of the drive current flowing through the electric motor for steering the rear wheels is limited to temporarily change the battery voltage. There is disclosed a rear wheel steering device which is designed to prevent such a significant decrease.

[0003]

In the steering device described in the above publication, the magnitude of the drive current of the motor is limited when the battery voltage drops.
Even if the maximum current is limited, the current continues to be supplied to the transistors that make up the motor drive circuit unless it is turned off.Therefore, not only will the battery voltage drop further, but the amount of heat generated from the transistors may increase. is there. Therefore,
In such a case, it is necessary to surely stop the supply of current to the motor. Further, if the steering control is simply stopped when the battery voltage drops, for example, when the steered wheels to be controlled are moved by an external force during the control stop, the measurement result of the steering angle measuring means does not represent a correct actual steering angle. Therefore, there is a possibility that a steep steering angle control may be performed when the battery voltage is restored, and it is necessary to take some measures against this.

Further, it is not preferable that the drive current is continuously supplied to the motor even when the sensor system used for steering control may be damaged. Therefore, when the sensor is abnormal, the supply of the drive current to the motor is stopped, but if the original target steering angle is set when the control is restarted after that, the steered steering angle control will be performed rapidly. Since it will be carried out, it is necessary to take measures against this.

Therefore, the present invention is directed to a vehicle steering control apparatus for controlling a steering angle of steered wheels by controlling a motor in accordance with a steering angle deviation between a target steering angle and an actual steering angle. It is an object of the present invention to surely stop the supply of the drive current to the motor when it drops.

It is another object of the present invention to surely stop the supply of the drive current to the motor even when the sensor provided to the steering control device is determined to be abnormal.

Further, when the battery voltage recovers to exceed a predetermined voltage, or when the sensor recovers from an abnormal state and is determined to be normal, it is another object of the present invention to enable smooth transition to normal steering angle control. To do.

[0008]

In order to achieve the above object, the present invention has a steering wheel WL to be controlled and a steering mechanism connecting the steering wheel WL, as shown in the outline of the configuration in FIG. SM, a motor MT that drives the steering mechanism SM, a battery BT that supplies a drive current to the motor MT, and a steering wheel W
Target rudder angle setting means DS for setting the target rudder angle of L, rudder angle measuring means AS for measuring the actual rudder angle of the steered wheels WL, and rudder angle deviation for calculating the rudder angle deviation between the actual rudder angle and the target rudder angle Calculation means AD
And a steering angle control means AC that controls the driving current of the motor MT according to the steering angle deviation to control the steering angle of the steered wheels WL, and compares the voltage of the battery BT with a predetermined voltage. A voltage determining means VS for determining and a target steering angle correcting means DC for setting an actual steering angle as a target steering angle when the voltage of the battery BT is determined to be equal to or lower than a predetermined voltage by the voltage determining means VS are provided. It is a thing.

In the above steering control device, when it is determined by the voltage determination means VS that the voltage of the battery BT has recovered from the state of being equal to or lower than the predetermined voltage and exceeded the predetermined voltage,
It is desirable to include target rudder angle change rate adjusting means RC for limiting and setting the change rate of the target rudder angle.

Further, as described in claim 3, a steering wheel WL to be controlled and a steering mechanism S for connecting the steering wheel WL.
M, a motor MT that drives the steering mechanism SM, a battery BT that supplies a drive current to the motor MT, and a steered wheel W
Target rudder angle setting means DS for setting the target rudder angle of L, rudder angle measuring means AS for measuring the actual rudder angle of the steered wheels WL, and rudder angle deviation for calculating the rudder angle deviation between the actual rudder angle and the target rudder angle Calculation means AD
And a steering angle control means AC that controls the driving current of the motor MT according to the steering angle deviation to control the steering angle of the steered wheels WL (hereinafter, not shown). Sensor abnormality determining means for determining whether the sensor used for the control is normal or abnormal, and target steering angle correcting means for setting the actual steering angle as the target steering angle when the sensor abnormality determining means determines that the sensor is abnormal. Should be provided.

In the steering control device according to the third aspect, when the sensor abnormality determining means determines that the sensor has recovered from the abnormal state and is normal, the rate of change of the target steering angle is limited and set. It is desirable to provide a target rudder angle change rate adjusting means.

[0012]

In the steering control device according to the first aspect of the present invention, the target steering angle setting means DS sets the target steering angle of the steering wheel WL to be controlled, and the steering angle measuring means AS controls the steering wheel. The actual steering angle of WL is measured. Then, the steering angle deviation calculating means AD calculates the steering angle deviation between the actual steering angle and the target steering angle. In accordance with this steering angle deviation, the steering angle control means AC controls the drive current of the motor MT, and the steering angle of the steered wheels WL is controlled. On the other hand, the voltage of the battery BT that supplies the drive current to the motor MT is compared with a predetermined voltage by the voltage determination means VS, and when it is determined that the voltage is less than the predetermined voltage, the actual steering angle is determined by the target steering angle correction means DC. It is set as the target rudder angle.
As a result, the steering angle deviation calculated by the steering angle deviation calculation means AD becomes zero, and the supply of the drive current from the battery BT to the motor MT by the steering angle control means AC is stopped.

In the steering control device according to the third aspect of the present invention, the sensor abnormality determining means determines whether the sensor is normal or abnormal. When it is determined that the sensor is abnormal,
The actual steering angle is set as the target steering angle by the target steering angle correction means. As a result, the steering angle deviation calculated by the steering angle deviation calculation means becomes zero, and the supply of the drive current from the battery to the motor by the steering angle control means is stopped.

In addition to the steering control device according to claim 1 or 3, according to the steering control device according to claim 2 or 4, further comprising a target steering angle change rate adjusting means, the supply of the drive current to the motor is temporarily stopped. When the control is restarted after the stop, the rate of change of the target steering angle is limited and the steering angle of the steered wheels gradually recovers. That is, when it is determined by the voltage determination means that the battery voltage has recovered from the state of being equal to or lower than the predetermined voltage and has exceeded the predetermined voltage, the target steering angle change rate adjusting means is set to limit the rate of change of the target steering angle. Also, even when the sensor abnormality determination means determines that the sensor recovers from the abnormal state and is normal, the target steering angle change rate adjusting means sets the change rate of the target steering angle to be limited. The steering angle of the steered wheels gradually recovers, and the normal steering control smoothly shifts.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the steering control device of the present invention will be described below with reference to the drawings. The present embodiment relates to a rear wheel steering control device that steers rear wheels in response to steering of front wheels of a vehicle. FIG. 2 shows an overall configuration of a vehicle equipped with a steering control device. The front wheels 13 and 14 are steered by a front wheel steering mechanism 10 in accordance with a turning operation of a steering wheel 19. The front wheel steering mechanism 10 includes, for example, a front wheel steering angle sensor 17 of a potentiometer for detecting the steering angle amounts of the front wheels 13 and 14.
Is provided, and the measurement data is supplied to the electronic control unit 20.

Further, a yaw rate sensor 8 is provided, whereby a changing speed of a vehicle rotation angle (yaw angle) around a vertical axis passing through the center of gravity of the vehicle, that is, a yaw angular velocity (yaw rate).
Is detected, and the electronic control unit 20 is operated as yaw rate γ.
Is supplied to. Further, a vehicle speed sensor 9 for detecting the speed of the vehicle is provided, and a signal representing the vehicle speed Vs of the output is supplied to the electronic control unit 20. As the vehicle speed sensor 9, a pair of sensors may be used to detect the vehicle speed in two systems, and the average value or the maximum value thereof may be output as the vehicle speed Vs. Can be detected.

A rear wheel steering mechanism 18 is connected to the rear wheels 15 and 16 and steered according to the rotation of the motor 12.
In this embodiment, the motor 12 is a three-phase brushless motor,
A relative steering angle sensor 61 that detects the rotation angle of the motor 12 is provided at the axial end portion. As the relative steering angle sensor 61, a magnetic pole sensor that outputs a magnetic pole signal according to a change in the magnetic pole of the motor 12 is used, or a general rotary encoder is used, but the output signal represents a relative steering angle. become. In this embodiment, two sets of magnetic pole sensors are provided, and the steering control can be continued even if one of them fails. Also,
As shown in FIGS. 2 and 3, an absolute steering angle sensor 62 of a potentiometer for detecting the steering angle amounts of the rear wheels 15 and 16 is provided. Thus, the relative steering angle sensor 61 and the absolute steering angle sensor 62 constitute a rear wheel steering angle sensor 60 (FIG. 5), which detects the actual steering angles of the rear wheels 15 and 16.

As shown in FIG. 3, the rear wheel steering mechanism 18 of this embodiment has a cover 52 fixed to a housing 51. The cover 52 and the motor housing 53 of the motor 12 and the relative steering angle sensor 61 are integrated with the cover 52. Is provided.
As is clear from FIG. 4, a rack shaft 55 is provided at right angles to the traveling direction of the vehicle, and both ends of the rack shaft 55 are connected to knuckle arms of rear wheels via ball joints 58. A tube 59 is fitted to the right end of the housing 51 in FIG.
Even in the case of providing 5, the tube 59 can be dealt with without changing the housing 51 by exchanging the tube 59. A rack 56 is formed on the rack shaft 55, and the rack 56 is configured to mesh with a pinion 57 extending in the front-rear direction of the vehicle.

As shown in FIG. 4, a pinion 12p is provided at the tip of a motor shaft 12s of the motor 12, and a gear 12g meshes with the pinion 12p to form a hypoid gear. This hypoid gear is the motor 12
The rotation of the motor shaft 12s is transmitted as the rotation of the gear 12g, but when the rotational force is applied to the gear 12g from the rack shaft 55 side, the reverse efficiency is set to zero so that the motor shaft 12s of the motor 12 does not rotate. Has been done.

The motor 12 is constructed so as to be controlled by a signal from the electronic control unit 20. That is, the electronic control unit 20 includes the yaw rate sensor 8,
Vehicle speed sensor 9, front wheel steering angle sensor 17, relative steering angle sensor 6
1 and a rear wheel steering angle sensor 60 including an absolute steering angle sensor 62
Etc. are supplied, and the motor 12 is supplied in accordance with these outputs.
Is set and the control signal is supplied to the motor 12.

FIG. 5 shows the structure of the electronic control unit 20. The electronic control unit 20 has a battery 41 mounted on the vehicle.
Is connected. That is, the battery 41 is connected to the motor driver 44 through the fuse and the power supply terminal IP1, and is connected to the motor driver 44 and the constant voltage regulator 43 through the fuse, the ignition switch 42 and the power supply terminal IP2. The constant voltage regulator 43 outputs a constant voltage Vcc. The power supply terminal IP2 is connected to the interface 46, and a signal representing the voltage of the battery 41 (hereinafter, referred to as battery voltage Vb) is input to the microprocessor 45 via the interface 46.

The electronic control unit 20 has a microprocessor 45 operated by a constant voltage Vcc, and has the yaw rate sensor 8, the vehicle speed sensor 9, and the front wheel steering angle sensor 17 described above.
The detection signal of the rear wheel steering angle sensor 60 is also input to the microprocessor 45 via the interface 46.
The terminals of each phase of the motor 12 are connected to the motor driver 44 of the electronic control unit 20. Motor driver 44
Is supplied with power from the power supply terminals IP1 and IP2. Then, the control signal is output from the microprocessor 45 to the motor driver 44.

In the microprocessor 45, FIG.
The target rudder angle is set according to the control block diagram shown in (1), and the servo control of the motor 12 is performed. First, in the target value setting unit 21, for example, the rear wheels 1 are set according to the steering angle δ of the front wheels 13, 14 and the yaw rate γ, and the vehicle speed Vs.
Target steering angles θa of 5 and 16 are set. Specifically, in the target value setting unit 21, the product of the coefficient K1 set according to the vehicle speed Vs and the output yaw rate γ of the yaw rate sensor 8 and the coefficient K2 set according to the vehicle speed Vs and the front wheel steering angle sensor 17 are set. The product of the output steering angle δ of is added (K1 · γ + K
2 · δ) and the target steering angle θa are set. For example, when the vehicle is stopped, the target steering angle θa is set so that the rear wheels 15 and 16 are steered in the opposite direction to the front wheels 13 and 14 in inverse proportion to the steering angles of the front wheels 13 and 14, and accordingly, the target steering angle θa is set. The turning radius becomes smaller. Further, when the vehicle is traveling at high speed, the target steering angle θa is set to be proportional to the steering angle of the front wheels 13 and 14, and the rear wheels 15 and 16 are set to the front wheels 13 and 14.
The steering is performed in the same direction as, and the steering stability when the vehicle turns becomes good.

The target steering angle θa set as described above is
The differentiator 22 differentiates, and the differential gain setting part 23 differentiates the differential value Dθa according to a predetermined characteristic.
θa is obtained. That is, when the absolute value of the differential value Dθa is less than or equal to a predetermined value (for example, 0.12 deg), the differential gain Gθa is set to 0, and when the absolute value of the differential value Dθa is at least a predetermined value (for example, 0.48 deg). Is the differential gain G
θa is set to a predetermined value (for example, 4). Therefore, FIG.
As shown in, when the absolute value of the differential value Dθa is within the range of 0.12 to 0.48 deg, the differential gain Gθ
a has a value of 0 to 4.

On the other hand, the rotation angle θm of the motor 12 is detected by the relative steering angle sensor 61, is output as the actual steering angle θr via the steering angle conversion unit 33, and is supplied to the subtraction unit 24. The output of the relative steering angle sensor 61 is a relative steering angle as described above and does not represent the actual steering angle, but is corrected by the steering angle conversion unit 33 based on the output of the absolute steering angle sensor 62. The actual steering angle θr is output from the steering angle conversion unit 33.

In the subtracting section 24, the actual steering angle θr is subtracted from the target steering angle θa to obtain the steering angle deviation Δθa. This steering angle deviation Δθa is, as shown in FIG.
When the absolute value of the steering angle deviation Δθa is less than or equal to the predetermined value α, the deviation θ of the output is processed through the steering angle deviation dead zone providing unit 25.
d is set to 0. Thus, the control is configured to stop when the value of the steering angle deviation Δθa is small. The deviation θd thus obtained is sent to the differentiating section 26 and the proportional section 28. The proportional portion 28 multiplies the deviation θd by a predetermined proportional gain to obtain the proportional term Ps. Further, the deviation θd is differentiated in the differentiator 26, and the steering angle deviation differential value Dθ is obtained.
d is obtained.

Then, the steering angle deviation differential value Dθd is multiplied by the differential gain Gθa set by the differential gain setting unit 23 as described above in the multiplication unit 27 to obtain the differential term Ds. Then, the proportional term Ps and the differential term Ds are added to the adder 29.
And the steering angle control amount, that is, the steering angle value θc is obtained. The steering angle deviation limiter 30 limits the steering angle value θc to set the control amount Oc in proportion to the steering angle value θc as shown in FIG. 11, and the control amount Oc is set to a predetermined value. It is set so as not to be higher than the upper limit value (for example, 1.5 deg) or lower than a predetermined lower limit value (for example, -1.5 deg).

The control amount Oc thus obtained is converted into a duty Dy by the deviation-duty converter 31 and supplied to the pulse width modulation (PWM) unit 32. In the pulse width modulator 32, a pulse signal Pw corresponding to the duty Dy is formed and output to the motor driver 44. The motor driver 44 servo-controls and rotationally drives the motor 12 according to the pulse signal Pw supplied thereto. An integral term may be added to the PD control.

When setting the target steering angle θa and the differential term Ds, the microprocessor 45 uses, for example, FIG.
The correction is performed according to the flowchart shown in FIG. That is, 5 ms after initialization is performed in step 101
Motor servo control is performed in each cycle (steps 102 and 108), but during this period, steps 105, 106 or step 10 are performed depending on the magnitude of the battery voltage Vb.
Step 7 is performed. Specifically, after the above-mentioned various control amounts such as the target steering angle θa are calculated in step 103,
In step 104, the voltage of the battery 41 (battery voltage Vb) is compared with the predetermined voltage Vk.

In step 104, the battery voltage V
If b is determined to be equal to or lower than the predetermined voltage Vk, step 105
Then, the actual steering angle θr is set as the target steering angle θa. That is, the actual steering angle θr is directly used as the target steering angle θa. Furthermore, since the previous value of the differential term Ds may remain even if only the steering angle deviation Δθa is set to zero, the differential term Ds is cleared (0) in step 106, and when the integral term exists, This is also cleared (0). Then, step 108
And the motor 12 is servo-controlled as described above,
After steps 105 and 106, the steering angle deviation Δθa becomes zero, and the differential term Ds is also zero, so that no drive current is supplied to the motor driver 44, and therefore the transistors that form the same generate heat. Nor.

On the other hand, when it is determined in step 104 that the battery voltage Vb is higher than the predetermined voltage Vk, the rate of change of the target steering angle θa is limited in step 107, and the routine proceeds to step 108. That is, the battery voltage Vb is the predetermined voltage V
When the target steering angle θa suddenly rises, such as when the vehicle recovers from the state of k or less and exceeds the predetermined voltage Vk, rapid steering angle control is performed, which is not appropriate. Therefore, in such a case, the rate of change (here, the rate of increase) of the target steering angle θa is limited, and the servo control is performed so that the target steering angle θa gradually approaches the target steering angle θa.

For example, as shown in FIG. 12, when the battery voltage Vb is equal to or lower than the predetermined voltage Vk, the actual steering angle θr indicated by the broken line is the target steering angle θr in contrast to the original target steering angle θao indicated by the solid line.
It is set as a. From this state, when the battery voltage Vb recovers to exceed the predetermined voltage Vk at tk, if it is immediately set to the original target steering angle θao at that time, it rapidly increases at the position (tk) shown by the alternate long and short dash line in FIG. ,
This is not preferable because abrupt steering angle control will be performed. Therefore, the rate of change (rate of increase) of the target steering angle θa is limited, and the difference from the original target steering angle θao is controlled to be gradually reduced. As a result, the target steering angle θa is servo-controlled so as to gradually approach the original target steering angle θao shown by the solid line, as shown by the chain double-dashed line.

In step 107, by comparing the previous value and the current value of the battery voltage Vb, the battery voltage Vb is changed from the predetermined voltage Vk to the predetermined voltage Vk.
The rate of change of the target steering angle θa is limited only when it is determined that the target steering angle θa has been recovered until it exceeds k. Since it is not necessary to limit the rate of change during normal control other than such a case, step 107 Jump to step 108
It is also possible to proceed to the servo control of the motor 12.

As described above, in this embodiment, when the battery voltage Vb is determined to be equal to or lower than the predetermined voltage Vk,
Since the steering angle deviation Δθa is set to zero and the differential term Ds is set to zero (when the integral term exists, this is also set to zero),
No current is supplied to the transistor that constitutes the motor driver 44, and therefore heat generation is prevented. Furthermore,
Even if the drive current to the motor 12 is set to zero, the motor 12 is gradually driven when an external force is applied to the rear wheels 15 and 16 to be steered, but even in this state, the actual steering angle θr is set as the target steering angle θa. Is used, the steering angle deviation Δθ
a is always zero, and the target steering angle θa (= θ
r) is used for starting control.

FIG. 8 shows another embodiment of the present invention.
The target steering angle correction or the target steering angle change rate adjustment described above is performed according to the failure determination result of the yaw rate sensor 8, the front wheel steering angle sensor 17, and the like. In this embodiment, in steps 201 to 203, step 101 in FIG.
After being processed in the same manner as in steps 103 to 103, a sensor failure determination is made in step 204. Here, if the sensor is determined to be abnormal and this state continues for a predetermined time Td, the routine proceeds from step 205 to step 206, where failure control is performed, and, for example, a stop operation is performed. When the predetermined time Td has not elapsed after it is determined that the sensor is abnormal, the actual steering angle θr is set as the target steering angle θa in step 207,
In step 208, the differential term Ds is cleared (0).
If there is an integral term, this is also cleared.

The reason why the sensor state is determined during the predetermined time Td is to avoid the influence of noise or the like. For example, the change over time of the failure determination result of the sensor is monitored, and if it is determined that the sensor has recovered from the abnormal state and becomes normal, the rate of change of the target steering angle θa is limited in step 209. Accordingly, in accordance with this, the steering angle control is gradually performed in step 210, and is controlled so as to gradually approach the target steering angle θa.

As described above, in the present embodiment, when the sensor is determined to be abnormal, the steering angle deviation Δθa is set to zero and the differential term Ds is set to zero (when there is an integral term, the steering term deviation Δθa is set to zero). This is also zero), so that no current is supplied to the transistor forming the motor driver 44. Moreover, when the sensor recovers from the abnormal state and is determined to be normal, the rate of change of the target steering angle θa is limited, so that the steering angle gradually recovers and the normal control is smoothly performed.

[0038]

Since the present invention is constructed as described above, it has the following effects. That is, the steering control device according to claim 1 is configured such that when the battery voltage is determined to be equal to or lower than the predetermined voltage, the target steering angle correction means sets the actual steering angle as the target steering angle. The supply of the drive current to the motor can be reliably stopped and set to zero.

A steering control device according to a third aspect of the present invention is
Even when the sensor abnormality determination means determines that the sensor is abnormal, the target steering angle correction means sets the actual steering angle as the target steering angle, so that the drive current to the motor is surely zero. Can be

Further, in the steering control device according to the second or fourth aspect, when the control is restarted after the supply of the drive current to the motor is once stopped, the change rate of the target steering angle is limited, and the steering angle of the steered wheels is limited. Is configured to gradually recover, so that it is possible to avoid a sudden steering angle control and smoothly shift to normal control.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a configuration of a vehicle steering control device of the present invention.

FIG. 2 is an overall configuration diagram of a vehicle steering control device according to an embodiment of the present invention.

FIG. 3 is a front view of a rear wheel steering mechanism according to an embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a rear wheel steering mechanism according to an embodiment of the present invention.

FIG. 5 is a circuit configuration diagram of an electronic control unit used in an embodiment of the present invention.

FIG. 6 is a control block diagram relating to servo control of a motor in one embodiment of the present invention.

FIG. 7 is a flowchart showing a steering control process according to an embodiment of the present invention.

FIG. 8 is a flowchart showing a steering control process according to another embodiment of the present invention.

FIG. 9 is a graph showing the input / output characteristics of the differential gain setting section in the embodiment of the present invention.

FIG. 10 is a graph showing the input / output characteristics of the steering angle deviation dead zone applying section in the embodiment of the present invention.

FIG. 11 is a graph showing the input / output characteristics of the steering angle deviation limiter in one embodiment of the present invention.

FIG. 12 is a graph showing how the target steering angle change rate is adjusted in one embodiment of the present invention.

[Explanation of symbols]

 8 Yaw rate sensor 9 Vehicle speed sensor 11 Rear wheel steering angle sensor 12 Motor 17 Front wheel steering angle sensor 20 Electronic control unit 22 Differentiation part, 23 Differential gain setting part 24 Subtraction part 25 Steering angle deviation dead zone applying part 26 Differentiation part, 27 Multiplication part 28 Proportional section, 29 Addition section 30 Steering angle deviation limiter 31 Deviation-duty conversion section 32 Pulse width modulation section, 33 Steering angle conversion section 43 Constant voltage regulator 44 Motor driver 45 Microprocessor 46 Interface 60 Rear wheel steering angle sensor 61 Relative steering angle Sensor, 62 Absolute steering angle sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B62D 137: 00 (72) Inventor Hideki Katsuraya 2-1, Asahi-cho, Kariya city, Aichi Aisin Seiki Co., Ltd. In the company

Claims (4)

[Claims] 1. A steering wheel to be controlled, a steering mechanism that connects the steering wheel, a motor that drives the steering mechanism, a battery that supplies a driving current to the motor, and a target steering angle of the steering wheel. Target rudder angle setting means for setting, rudder angle measuring means for measuring the actual rudder angle of the steered wheels, rudder angle deviation calculation means for calculating the rudder angle deviation between the real rudder angle and the target rudder angle, and the rudder In a steering control device for a vehicle, which comprises a steering angle control means for controlling a drive current of the motor according to an angular deviation to control a steering angle of the steered wheels, a voltage determination for comparing the voltage of the battery with a predetermined voltage. And a target steering angle correction unit that sets the actual steering angle as the target steering angle when the voltage determination unit determines that the battery voltage is equal to or lower than the predetermined voltage. Steering control device. 2. A target set by limiting the rate of change of the target steering angle when the voltage determination means determines that the voltage of the battery has recovered from the state of being equal to or lower than the predetermined voltage and has exceeded the predetermined voltage. The vehicle steering control apparatus according to claim 1, further comprising a steering angle change rate adjusting unit. 3. A steering wheel to be controlled, a steering mechanism that connects the steering wheels, a motor that drives the steering mechanism, a battery that supplies a driving current to the motor, and a target steering angle of the steering wheel. Target rudder angle setting means for setting, rudder angle measuring means for measuring the actual rudder angle of the steered wheels, rudder angle deviation calculation means for calculating the rudder angle deviation between the real rudder angle and the target rudder angle, and the rudder A steering control device for a vehicle, comprising: a steering angle control means for controlling a drive current of the motor according to an angular deviation to control a steering angle of the steered wheels. A sensor used for controlling the steering control device is normal or abnormal. And a target steering angle correction unit that sets the actual steering angle as the target steering angle when the sensor abnormality determination unit determines that the sensor is abnormal. The vehicle steering control device. 4. The target steering angle change rate adjusting means for limiting and setting the change rate of the target steering angle when the sensor abnormality determination means determines that the sensor has recovered from an abnormal state and is normal. The steering control device for a vehicle according to claim 3, wherein: