JP2982584B2 - Position control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a position control device having a position sensor for detecting a control operation position by contact, such as a steering angle sensor used in a rear wheel steering angle control device, in a control system.

[0002]

2. Description of the Related Art Conventionally, as a rear wheel steering angle control device using a contact type steering angle sensor, the one shown in FIG. 6 is known.

[0003] This involves inputting a front wheel steering angle detection value detected by a front wheel steering angle sensor 107 and a vehicle speed detection value detected by a vehicle speed sensor 108 to a control unit 105 to calculate a target rear wheel steering angle value. The driver 106 supplies a current for driving the motor 102 so as to have the calculated target rear wheel steering angle value, thereby operating the actuator 101 and the main rear wheel steering angle sensor 103.
The rear wheel steering angle value detected from the rotation angle of the motor 102 by the
The rear wheel steering angle values detected from the stroke 01 are input to the control unit 105, and control is performed to operate the actuator 101 such that the rear wheel steering angle values match the target rear wheel steering angle.

[0004]

However, in the above prior art, each of the rear wheel steering angle sensors 103, 1 is required.
04 is of a contact type using a potentiometer, and its neutral position is fixed (determined) by design. In a normal vehicle, since there are usually many straight runnings, there are many zero servo states and the neutral position There has been a problem that the nearby contacts are easily worn and the deterioration of the sensors 103 and 104 is accelerated.

The present invention has been made in view of the above problems. A first object of the present invention is to provide a position control apparatus having a position sensor for detecting a control operation position by contact in a control system. Another object of the present invention is to prevent the deterioration of the position sensor.

A second object is to prevent wear deterioration of the rear wheel steering angle position sensor while minimizing the influence on the vehicle behavior.

[0007] A third object is to improve the durability of the position sensor by effectively preventing abrasion.

[0008]

In order to achieve the first object, according to the first aspect of the present invention, as shown in the claim correspondence diagram of FIG. 1, a control operation position is detected by contact. A position sensor a, a target position calculating means b for calculating a target position, and an actuator c for controlling the position detection value detected by the position sensor a to be the target position calculated by the target position calculating means b. The position control means d and the neutral position used for controlling the actuator c are not overlapped within the range that does not affect the vehicle behavior from the true neutral position detected by the position sensor a .
And a neutral position setting means e for shifting and setting .

In order to achieve the second object, in the invention according to claim 2 (second invention), the position control device is a rear wheel steering angle control device, and the neutral position used for controlling the actuator is the target position. It is set when the power of the calculating means is turned on or reset, and is not changed during the operation of the rear wheel steering angle control device.

In order to achieve the third object, in the invention according to claim 3 (third invention), the neutral position used for controlling the actuator is randomly set within a predetermined range.
Alternatively, they are sequentially changed.

[0011]

The operation of the first invention will be described.

At the time of position control, the actuator c is controlled by the position control means d such that the position detection value detected by the position sensor a becomes the target position calculated by the target position calculation means b. Neutral position used for controlling the actuator c of carrying out the this position control is in the neutral position setting means e, within range not affected from the true neutral position detected by the position sensor a in vehicle behavior, the same position is duplicated It is set so as not to shift .

Therefore, in the position sensor a for detecting the control operation position by contact, the neutral position contact point with the highest contact frequency is shifted, and wear of the position sensor a is prevented from being deteriorated.

The operation of the second invention will be described.

At the time of rear wheel steering angle position control, position control means d
In, the actuator c is controlled such that the detected value of the rear wheel steering angle position detected by the position sensor a becomes the target rear wheel steering angle position calculated by the target position calculating means b.
The neutral position used for controlling the actuator c in performing the rear wheel steering angle position control is a neutral position setting means e.
Is set when the target position calculating means b is turned on or reset, and is not changed during the operation of the rear wheel steering angle control device.

Therefore, since the setting of the change of the neutral position is performed only before the start of control other than during the control operation and at the time of the control interruption, the position for detecting the rear wheel steering angle while minimizing the influence on the vehicle behavior is minimized. The wear deterioration of the sensor a is prevented.

The operation of the third invention will be described.

Since the neutral position used for controlling the actuator c is changed randomly or sequentially within a predetermined range, the durability of the position sensor a is improved by effective wear prevention in which the shift position is not specified. .

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

First, the configuration will be described.

FIG. 2 is an overall system diagram showing an electric motor-driven four-wheel steering vehicle to which the position control device according to the embodiment of the present invention is applied. FIG. 3 is a diagram showing an electric rear wheel steering mechanism of the embodiment vehicle. FIG. 4 is a block diagram showing a rear wheel steering angle position control device of the example vehicle.

In FIG. 2, reference numerals 1 and 2 denote front wheels, 3 and 4 denote rear wheels, 5 denotes a mechanical front wheel steering mechanism, and 6 denotes an electric rear wheel steering mechanism (corresponding to an actuator c).

The mechanical front wheel steering mechanism 5 increases a steering force input from a steering wheel 7 steered by a driver via a steering shaft 8 by a power steering (not shown), and increases the increased steering force to a rack shaft 9. Through the side rods 10 and 11 and the knuckle arms 12 and 13 to provide a steering angle to the front wheels 1 and 2.

The electric rear wheel steering mechanism 6 includes four
The rotational force of the high cas motor 15 controlled by the motor output from the WS control unit 14 is reduced by the worm 16 and the worm wheel 17, and the rotational movement of the worm wheel 17 is reduced by the gear of the pinion shaft 18 and the gear of the rack shaft 19. Is converted into linear motion of the rack shaft 19, and the rack shaft 19
From the side rods 20, 21 and the knuckle arm 22,
23 to provide a steering angle to the rear wheels 3 and 4.

The 4WS control unit 14 includes:
As shown in FIG. 4, the interface unit 14a, the A / D
It has a conversion section 14b, a target rear wheel steering angle calculation section 14c, a neutral position motor rotation angle equivalent value setting section 14d, a random number generation section 14e, an addition calculation section 14f, a motor rotation angle equivalent calculation section 14g, a subtractor 14h, and a driver 14i. .

The interface section 14a includes a sensor signal from the steering sensor 26 and a vehicle speed sensor 2
7 is input.

Sensor signals from a rear steering angle main sensor (corresponding to a position sensor a) 24 and a rear steering angle sub-sensor 25 are input to the A / D converter 14b. here,
The rear steering angle main sensor 24 is connected to the pinion shaft 18.
The sensor value is used for control as positioning feedback information for rear wheel steering angle control. The rear steering angle sub-sensor 25 is a sensor that detects the stroke amount of the rack shaft 19, and is used for monitoring the abnormality of the rear steering angle main sensor 24.

The target rear wheel steering angle calculation section 14c receives the front wheel steering angle detection value and the vehicle speed detection value from the interface section 14a and calculates a target rear wheel steering angle value based on these detection values (target position). (Equivalent to the calculating means b).

The neutral position motor rotation angle equivalent value setting unit 1
4d initializes the designed neutral position motor rotation angle as a numerical value calculated by the microcomputer. The random number generator 14e
Generates a random number r used to arbitrarily shift the neutral position. The addition calculator 14f calculates the current rear wheel steering angle neutral position using the random number r output from the random number generator 14e. The neutral position motor rotation angle equivalent setting unit 14d,
The random number generation unit 14e and the addition calculation unit 14f correspond to the neutral position setting means e, and perform calculation processing only when the ignition is turned on.

The motor rotation angle equivalent value calculation unit 14g includes:
The target rear wheel steering angle value calculated by the target rear wheel steering angle calculation unit 14c and the rear wheel steering angle neutral position calculated by the addition calculation unit 14f are input, and the rear wheel steering angle neutral position is calculated using the rear wheel steering angle neutral position. A motor rotation angle equivalent value (a numerical value calculated by a microcomputer) is calculated from the wheel steering angle value.

The adder / subtractor 14h has a motor rotation angle equivalent value calculated by the motor rotation angle equivalent value calculation unit 14g and a sensor signal from the rear steering angle main sensor 24 that has been A / D converted by the A / D conversion unit 14b. And outputs a drive signal to the driver 14i so that the rotation amount of the pinion shaft 18 matches the motor rotation angle equivalent value.

The driver 14i supplies a servo current to the high cas motor 15 according to a drive signal input from the adjuster 14h.

Next, the operation will be described.

[Neutral Position Setting Operation] FIG. 5A is a flowchart showing the flow of the neutral position setting processing operation used for controlling the electric rear wheel steering mechanism 6 in the 4WS control unit 14, and each step will be described below. I do.

In step 50, the neutral position motor rotation angle equivalent value θro which is a value calculated by the microcomputer of the neutral position is set to θro.
= 512.

At step 51, in order to arbitrarily shift the neutral position, r = ± 25 corresponding to the rear wheel steering angle | 0.05 ° |
Generates a random number r within the range

When the maximum rear wheel steering angle of the electric rear wheel steering mechanism 6 as an actuator is set to, for example, | 1 ° |, and the A / D conversion is performed in 10 bits (0 to 1024), the rear wheel steering angle The neutral position is 512, and the rear wheel steering angle |
05 ° | corresponds to ± 25.

In step 52, using the random number r, the neutral position of the rear wheel steering angle this time is set to the neutral position motor rotation angle equivalent value θ.
It is offset from ro by the equation θro ′ = θro + r.

Thus, the neutral position is θro '= 487-
This is set within the range of 537.

In step 53, the control cycle is set to, for example,
When 5 msec is set, a timer for waiting for an interrupt every 5 msec is started.

Steps 50 to 53 are performed only once when the ignition is turned on.

[Rear Wheel Steering Angle Control Operation] FIG. 5B is a flowchart showing the flow of the rear wheel steering angle control processing operation performed in the 4WS control unit 14 for each control cycle. Each step will be described below.

In step 54, the rear wheel steering angle detected by the rear steering angle main sensor 24 and the steering sensor 26
, The front wheel steering angle detected from the vehicle speed and the vehicle speed detected from the vehicle speed sensor 27 are read.

In step 55, based on the front wheel steering angle and the vehicle speed read in step 54, the target rear wheel steering angle value δr (−1 ° to +1) is set to a predetermined vehicle motion target value.
°) is calculated.

In step 56, the target rear wheel steering angle value δ
r is converted into a motor rotation angle equivalent value θr (0 to 1024). For example, it can be obtained by θr = K * δr + θro '. Here, K is a constant for converting the target rear wheel steering angle value δr into a motor rotation angle equivalent value θr, and K = 512 in the electric rear wheel steering mechanism 6 which is the present actuator.

In step 57, the position of the high cas motor 15 is controlled based on the target rear wheel steering angle value δr.

[Driving] When turning, the target rear wheel steering angle value δr is calculated based on the front wheel steering angle and the vehicle speed according to the flowchart of FIG. The rear wheel steering angle is controlled by outputting a servo current to the high cas motor 15 so that the deviation Δδ between the angle main sensor value δ ₁ and the target rear wheel steering angle value δr becomes zero. That is, the position feedback information of the rear wheel steering angle control rear steering angle main sensor value [delta] _1, the rear wheel steering angle is controlled to a neutral position to be used for actuator control as a reference, intended turning turning property and cornering stability is Achieved.

Here, the rear steering angle main sensor 24 detects the rotation angle of the motor 15 using, for example, a potentiometer (output 0 to 5 V), and is in a neutral position (position where the rear wheel steering angle is 0 °). Then, the potentiometer output is, for example, V0
= 0.25V. However, the frequency of straight traveling and turning traveling in vehicle traveling depends on road conditions etc., but generally the frequency of straight traveling is high,
The wear of the potentiometer is concentrated around the output V0 = 0.25V, and there is a possibility that the deterioration will be partially accelerated.

On the other hand, in the present embodiment, the above problem is solved by changing and setting the neutral position used for the actuator control when the ignition is turned on.

That is, by the neutral position setting process shown in FIG. 5A, the rear wheel steering angle | 0.05 is set every time the ignition is turned on.
Using the random number r within the range of ± 25 corresponding to ° |, the current rear wheel steering angle neutral position is offset from the neutral position motor rotation angle equivalent value θro by the equation θro ′ = θro + r.

The rear wheel steering angle | 0.05 ° | is set such that the neutral position of the rear wheel steering angle does not affect the vehicle behavior. This is because the steering gear ratio is, for example, 1:
When converted to the steering angle for 15 vehicles, | 0.75 ° |
This is because it is considered that there is almost no influence of discomfort due to a change in vehicle behavior on the driver.

Next, the effects will be described.

(1) In a position control device having a rear steering angle main sensor 24 for detecting a control operation position by contact in a control system, a true position where the rear steering angle main sensor 24 detects a neutral position used for controlling an actuator. Since the neutral position is set so as to be shifted from the neutral position within a range that does not affect the behavior of the vehicle, the deterioration of the rear steering angle main sensor 24 can be prevented.

(2) The position control device is a rear wheel steering angle control device, the neutral position used for controlling the actuator is set when the ignition is turned on, and the neutral position is changed during the operation of the rear wheel steering angle control device. Therefore, the deterioration of the rear steering angle main sensor 24 can be prevented while minimizing the influence on the vehicle behavior.

(3) Since the neutral position used for controlling the actuator is set randomly using a random number r within a range of ± 25, the durability of the rear steering angle main sensor 24 is reduced by effective wear prevention. Improvement can be achieved.

Although the embodiment has been described with reference to the drawings, the specific configuration is not limited to the embodiment, and any changes or additions without departing from the spirit of the invention are included in the invention. It is.

For example, in the embodiment, the rear wheel steering angle control device of the electric motor driven four-wheel steering vehicle has been described as an example. However, another position control device using a contact type feedback sensor such as a potentiometer, for example, Also, the present invention can be applied to an electronic throttle control device for an automobile.

[0058]

According to the first aspect of the present invention, in a position control device having a position sensor for detecting a control operation position by contact in a control system, the position sensor detects a neutral position used for controlling the actuator. The same position does not overlap within the range that does not affect the vehicle behavior from the true neutral position
Since the apparatus is provided with the neutral position setting means for setting the position sensor so as to be shifted, an effect is obtained that the deterioration of the position sensor can be prevented.

According to the second aspect of the present invention, the position control device is a rear wheel steering angle control device, and the neutral position used for controlling the actuator is set when the target position calculation means is turned on or reset, and the rear wheel is set. Since the change is not performed during the operation of the steering angle control device, an effect is obtained that the deterioration of the rear wheel steering angle position sensor can be prevented from being deteriorated while the influence on the vehicle behavior is minimized.

According to the third aspect of the present invention, the neutral position used for controlling the actuator is changed randomly or sequentially within a predetermined range.
The effect that the durability of the position sensor can be improved by effective wear prevention can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram corresponding to claims showing a position control device of the present invention.

FIG. 2 is an overall system diagram showing an electric motor driven four-wheel steering vertical vehicle to which the position control device of the embodiment of the present invention is applied.

FIG. 3 is a diagram showing an electric rear wheel steering mechanism of an electric motor driven four-wheel steering vehicle to which the embodiment device is applied.

FIG. 4 is an electronic control system diagram centering on a 4WS control unit of the embodiment vehicle.

FIG. 5 is a flowchart showing a flow of a neutral position setting processing operation and a rear wheel steering angle control operation performed by a 4WS control unit of the embodiment device.

FIG. 6 is a diagram showing an electric rear wheel steering mechanism of a conventional electric motor driven four-wheel steering vehicle.

[Explanation of symbols]

 a position sensor b target position calculation means c actuator d position control means e neutral position setting means

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-3-243468 (JP, A) JP-A-5-147548 (JP, A) JP-A-3-243469 (JP, A) (58) Field (Int.Cl. ⁶ , DB name) B62D 6/02 B62D 7/14

Claims (3)

(57) [Claims] 1. A position sensor for detecting a control operation position by a contact, a target position calculation means for calculating a target position, and a target position calculated by the target position calculation means for a position detection value detected by the position sensor. Position control means for controlling the actuator so that the neutral position used for controlling the actuator is set so that the same position does not overlap within a range that does not affect the vehicle behavior from the true neutral position detected by the position sensor. Shifted
And a neutral position setting means for determining the position. 2. The method according to claim 1, wherein the position control device is a rear wheel steering angle control device, and a neutral position used for controlling the actuator is set when the target position calculation means is turned on or reset. The position control device according to claim 1, wherein no change is made during the operation. 3. The position control device according to claim 1, wherein the neutral position used for controlling the actuator is changed randomly or sequentially within a predetermined range.