JP3004072B2 - Control device for actuator with friction of automobile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to, or to be used in the automobile
A control device for a frictional actuator, more specifically,
A first controller and an on-off controller connected to the first stage, the first controller comparing a first amount indicating an actual actuator position with a second amount indicating a desired actuator position; Calculating at least one input quantity to be input to a subsequent on-off controller, having friction and frictional force;
The present invention relates to a control device for an actuator.

[0002]

2. Description of the Related Art A closed-loop control system of this kind is known from German Offenlegungsschrift DE-OS 320 78 63 (US-PS 449).
9412). This publication describes a control device for an actuator having friction. An on / off controller is connected to the subsequent stage of the nonlinear controller. The on / off controller (two-position operation controller) switches only when the difference between the target value or the actual value of the control circuit changes. The characteristic curve of the non-linear controller is steeper at the switching point, but flat at the other points. The limiting device suppresses the switching frequency from increasing. This prevents the on / off controller from being frequently switched on and off. The entire system is analog.

[0003] The German Offenlegungsschrift DE-OS 3233290
(US Pat. No. 4,594,993) describes a device for controlling the exhaust gas recirculation rate of a diesel internal combustion engine. 3
The input amount of the position operation controller is output from the linear controller.
Also in this device, switching of the three-position operation controller is performed only when the difference between the target value or the actual value of the control circuit changes. In that case, by hysteresis, 3
Continuous on / off switching of the position operation controller is prevented.

[0004] Also, German Published Patent Application DE-OS 2726
987 describes dividing the control device into a digital part and an analog part. In that case, the digital part processes digital data and the analog part processes analog data.

[0005]

SUMMARY OF THE INVENTION It is an object of the invention to provide a control device of the kind mentioned at the outset in which the influence of friction can be reduced and the dynamics of closed-loop control can be improved.
It is an object of the present invention to provide a control device for a frictional actuator used in an automobile .

[0006]

According to the present invention, there is provided a frictional actuator for use in a motor vehicle.
Control apparatus , comprising a first controller and an on / off controller connected to a subsequent stage, wherein the first controller sets a first amount indicating an actual actuator position to a desired actuator position. Calculating a target value for the on-off controller in the subsequent stage by comparing the second value with the on-off controller;
Has a variable hysteresis width and the hysteresis
The cis width is determined when the actuator is turned on and off at the hysteresis width.
The friction force is offset when driven on / off by the controller.
But the actuator does not move yet
Value, and the hysteresis width is
A first controller for controlling the first amount, or the first amount,
The problem is solved by a configuration set according to the second quantity .

[0007]

By setting the hysteresis width of the control circuit in advance in accordance with the operating parameters, the characteristics of the closed-loop control device can be significantly improved. According to the device of the present invention, different hysteresis widths E can be adjusted according to various operating conditions such as the number of revolutions or the position of the actuator. Therefore, without moving the actuator itself,
The effects of friction can be compensated.

[0008] Further advantages and preferred embodiments of the invention are set out in the dependent claims.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.

In the following, the device of the present invention will be described by taking the actuator of a diesel fuel pump as an example. However, the device of the present invention has other frictional actuators,
In particular, it can be applied to an electromagnetic actuator. Therefore, for example, it can also be used for a throttle valve actuator.

If there is friction in the actuator, the position of the actuator does not change if the change in the operation signal is small. FIG. 1 shows the relationship between the current flowing through the actuator and the position of the actuator. In order for the actuator to assume the position X, different currents I1 and I2 are required depending on the history. When the actuator is at the position X with the actuator current I1, and it is desired to change the moving direction, the actuator current is first changed to I
It is necessary to raise to 2. The actuator position changes after the current has changed by the minimum amount H. Note that this minimum amount varies depending on various operating parameters. The amount of action is, for example, the position, temperature, number of revolutions, or manufacturing error of the actuator. In particular, it is effective to select the hysteresis width E so as to correspond to half of the minimum amount H.

FIG. 2 shows an outline of the closed-loop control device. A signal UI indicating the actual position of the actuator is input to the controller 10 via the A / D converter 70. Further, a signal US indicating a desired position (target position) of the actuator is sent to the controller 10 via the A / D converter 20.
Is entered. The controller 10 calculates a desired actuator current IS from this data and other data, and calculates the current I
S is supplied to the on / off controller 40 via the D / A converter 30 and the connection point 35. Further, the controller 10 calculates a hysteresis width E of the on / off controller 40 based on various quantities such as a desired cycle and a measurement cycle T. The hysteresis width E is input to the on / off controller 40 via the D / A converter 80. On / off controller 40 drives actuator 50 accordingly. The current II measured at the actuator is fed back to the junction 35. Furthermore, a signal UI relating to the actual position of the actuator is applied to the node 35 via an analog differentiating element 60 and the digital controller 10 via an A / D converter 70.
Is input to

Particularly preferably, as shown in FIG. 2, the controller 10 is constituted by digital, and other elements such as the on / off controller and the differential element are constituted by analog. Use of the digital controller 10 enables efficient adaptive adjustment.

In order to improve the stability of the control circuit, the actual position UI of the actuator is fed back via a differentiating element 60 to the input of the on / off controller. This differentiating element 60 is constituted by an analog. This is significantly more effective than incorporating a digital differentiating element in the controller 10. When a digital differentiating element is used, it is difficult to obtain a necessary approximation due to the sampling time and the final resolution of a widely used A / D converter.

The digital controller 10 sets the current target value IS and the hysteresis width E of the on / off controller 40 according to the desired position US of the actuator, the actual position UI of the actuator, and other operating parameters. The on / off controller 40 controls the actuator according to a comparison between the desired actuator current and the actual actuator current and according to a desired hysteresis width E. For this purpose, the controller connects or disconnects the actuator from the power supply voltage.

When the on / off controller 40 detects that the actual actuator current II is larger than the desired actuator current IS by the hysteresis width E, the on / off controller 40 cuts off the connection to the power supply voltage. When the actual actuator current II becomes lower than the desired actuator current IS by the hysteresis width E, the controller supplies a power supply voltage to the actuator. Each switching state of the on / off controller is supplied to the controller 10 and used for measuring the period T. The measurement of the period may be performed by the controller 10,
The measurement can be performed with different measurement elements 205.

FIG. 3 shows the time characteristic of the actuator current.
It is described in. Therefore, the actuator current I
I is described for time t. At time T1, the actuator current is the desired actuator current I
At this point, a power supply voltage is supplied to the actuator, and thereafter the actuator current increases. At time T2, the actuator current becomes greater than the desired actuator current by a hysteresis width E, at which point the actuator is disconnected from the power supply voltage. As a result, the actuator current II drops again and becomes smaller than the desired value IS by the hysteresis width E.

Accordingly, the value of the actuator current continuously fluctuates between a value larger and smaller by the hysteresis width E around the value of the desired actuator current. By appropriately setting the hysteresis width, the actuator current can be changed up and down between two current values. The switching time can be changed by setting the hysteresis width. The switching time is adjusted so that the actuator responds very quickly if the desired actuator current IS changes. When the desired actuator current IS is constant, the actuator itself does not move.

FIG. 4 shows a part of the controller 10 (position controller) for calculating the target value IS of the actuator current. A / D converter 70 and A / D converter 20
The desired position US of the actuator and the actual position UI of the actuator are input to the comparison point 110 via. The difference between the two signals is supplied to the integrator 120 and the proportional element 130.

Reference numerals 2 and 3 indicate that the proportional constant P and the integrator operation amount can be adjusted. Output signals of the proportional element 130 and the integrator 120 are input to the limiter 140 via the addition point 135. The output signal of the limiter 140 becomes the output signal of the controller 10 and the D / A converter 3
Output to 0.

The output signal of the limiter 140 and the difference forming point 11
An output signal of 0 (control deviation) is an input signal of the circuit 150. The output signal of the integrator 12
Acts on zero. Various operating parameters and control deviations are input to the circuit 160. This circuit 160 acts on the proportional element, as indicated by reference numeral 2.

According to the difference between the desired position US of the actuator and the actual position UI, the integrator 120 and the proportional element 13
0 each form an output signal, which is added at summing point 135. These two circuits 120, 130
The (integrator, proportional element) at least functions as a controller having PI characteristics. The maximum value of the output signal of the controller is limited by the limiter 140. In the D / A converter 30, the output signal of the limiter is converted into a signal indicating a desired actuator current IS.

In a particularly preferred embodiment of the invention,
The output signal of the limiter 140, that is, the control deviation
50 is input. This circuit 150 has an anti-reset windup function. When the output signal of the controllers 120, 130 exceeds the limit, that is, when the signal is limited by the limiter, the value of the integrator is fixed.

This is because the value of the integrator 120 is stored,
This means that the output signal of the controller does not increase further until it leaves the limit. If the value of the integrator is not fixed and the control deviation is applied for a relatively long period,
The value of the integrator may be very large in some cases. Subsequently, when the sign of the control deviation changes, the controller requires a very long time before the value of the integrator runs out. The circuit 150 improves the control quality of the controller. When a further control deviation occurs in the circuit 150, the integrator starts operating immediately after the sign change of the control deviation.

A particularly preferred embodiment of the present invention includes a circuit 16
0 is provided. In this circuit, the proportionality constant of the P element is adjusted according to one or more of quantities such as control deviation, power supply voltage, speed or fuel temperature. The proportional constant of the proportional element 130 can be adjusted according to these quantities.

Particularly preferably, the proportionality constant P is increased when the control deviation is small, as compared with the case where the control deviation is large. When the driving voltage is low and / or when the temperature is low, it is preferable to increase the proportionality constant P. On the other hand, when the rotation speed is high, it is preferable to decrease the proportionality constant P.

FIG. 5 shows in detail a part of the controller 10 for calculating the hysteresis width E of the on / off controller (periodic controller). For example, the target value calculation device 200 determines the rotation speed and the actuator position UI to US.
The target value TS related to the cycle is set according to various operation parameters. This cycle target value is compared with the actual value T of the cycle. Difference between these two signals (control deviation of periodic controller)
Is supplied to the cycle controller 210. Controller 210 has at least an I characteristic. The upper and lower limits of the output signal are limited by limiter 220.

At the addition point 225, the output signal of the map value generator 230 functioning as a pre-control is added to the output signal of the first limiter 220. The sum of both signals is limited in a second limiter 240 to a predetermined value. The output signal indicates the hysteresis width E and is supplied to the on / off controller 40 via the D / A converter 80.

By comparing the cycle target value TS with the actual cycle T, the controller 210 calculates a value related to the hysteresis width E. Since this value must be greater than the minimum value and less than the maximum value, the limiter 220
The value of the output signal of No. 10 is limited to a predetermined range.

The map value generator 230 allows for a wide range of sudden changes in actuator position. The map value generator stores a value related to the hysteresis width E according to the operation parameters. If the friction is large, it is necessary to increase the hysteresis width E to overcome the frictional force. As the hysteresis width E increases, the period P also increases. When the friction is small, the frictional force can be overcome with a small hysteresis width E. In that case, if the hysteresis width is large, the actuator itself will be moved.

In particular, the friction is related to the actuator position, so that the hysteresis width E is stored in the map value generator at least according to the actuator position. If the actuator position is large, the friction will be significant. In that case, it is necessary to increase the hysteresis width. When the actuator position is small, the hysteresis width is small. Because the friction is small. If the actuator position changes suddenly, a new value of the hysteresis width E is immediately output to the output of the second limiter 240.

In a simple embodiment of the device according to the invention, no period measurement is performed. The hysteresis width is then read from the map value generator as a function of various operating parameters. Therefore, the map value generator 230
Is corrected. The map value generator stores the hysteresis width according to the actuator position, the number of rotations, and other quantities. Devices of this kind can be realized particularly easily.

The above-described cycle controller is effective for an actuator having friction. In particular, it is effective when the friction value is different when the operating point is different and the operating state is different.

[0034]

As is apparent from the above description, according to the present invention , the frictional force in the actuator is canceled.
The actuator should be selected so that it does not move yet.
Actuator is turned on and off with wide hysteresis width
If the target value is constant, the actuator
Without moving itself and when the target value changes
Can move the actuator very quickly
Kill As becomes, to reduce the effects of frictional forces on the actuator to be capable of improving the dynamic characteristics of the system
Become .

[Brief description of the drawings]

FIG. 1 is a diagram showing a relationship between a current flowing through an actuator and a position of the actuator.

FIG. 2 is a block diagram schematically showing a control device.

FIG. 3 is a diagram showing a current flowing through an actuator with respect to time.

FIG. 4 is a block diagram showing details of a controller.

FIG. 5 is a block diagram showing details of a controller.

[Explanation of symbols]

 10 controller 40 on-off controller 50 actuator

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Roland Karelmeier 7107 Neckarsulm Weststrasse 10 (56) References JP-A-61-198310 (JP, A) JP-A-62-20647 (JP, A JP-A-61-123736 (JP, A) JP-A-61-117602 (JP, A) JP-A-60-27747 (JP, A) JP-A-1-214909 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G05D 3/00-3/20 F02D 41/00-41/40

Claims (8)

(57) [Claims] 1. An activator having frictional force for use in an automobile.
A first controller (10) and an on-off controller (40) connected to a subsequent stage thereof, wherein the first controller (10) is configured to control an actual actuator position (UI). ) Is compared with a second amount indicating a desired actuator position (US) to calculate a target value for a subsequent on-off controller (40), and the on-off controller (40) Hysteresis width
(E), and the hysteresis width is
The eta is turned on by the on / off controller at the hysteresis width.
When driven off, the friction force is canceled but the actuator
Is selected so that it does not move yet, and the hysteresis width is set by the first controller.
According to the first amount, or the first amount and the second amount
An actuator control device characterized by being set . 2. The control device according to claim 1, wherein the first controller is digitally configured and includes a position controller and a period controller. 3. The control device according to claim 1, wherein the first controller outputs a current target value of the on / off controller. 4. The control device according to claim 1, wherein at least one variable such as a control deviation, a power supply voltage, a rotational speed or a fuel temperature changes a control parameter of the first controller.
The control device according to any one of claims 1 to 7. 5. The control device according to claim 2, wherein the cycle controller outputs the hysteresis width E. 6. The periodic controller preferably has an I characteristic,
The control device according to claim 2, wherein the output signal is limited. 7. The hysteresis width according to claim 2 , wherein a hysteresis width is changed by a map value according to an actuator position in addition to the output signal of the periodic controller.
The control device according to Item. 8. The control device according to claim 1, wherein the actuator position is applied to an input of an on / off controller via an analog differentiating element.