JPH0764644A - Gain switching device for positioning servo mechanism - Google Patents

Abstract

PURPOSE:To attain a stable positioning sction with no waste of time by means of a servo mechanism by dealing in real time with the change of the target acceleration/deceleration or the distrubance. CONSTITUTION:A control means 3c is provided on a gain switching device to updata gain KB of stop mode by fetching the difference between product UBe of deviation E betwen the target load value and the feedback value and final gain KBe of stop mode and product UBi-1 of deviation E and gain KBi-1 set at each prescribed time point precedent each prescribed time point of stop mode at each prescribed time point after a gain switching time point when the load reaches the final positioning point and gain KA of action mode is switched to gain KB of stop mode.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gain switching device for a positioning servo mechanism and is used for positioning a motor or the like.

[0002]

2. Description of the Related Art A servo system for positioning a motor or the like usually employs a feedback system. This is controlled to stop at a predetermined target position by using the gain that is proportional to the deviation between the positioning command value, that is, the target value and the actual position fed back, or makes full use of the gain obtained by differentiating or integrating this deviation. To do.

Originally, in such position control, two kinds of gains are generally switched and used, that is, a gain that is easy to operate is set during operation and a gain that is not easily influenced by disturbance is set during stop. The position control is performed so that it can be accurately and quickly achieved without influence of disturbance.

However, in simple gain switching, when switching from the operating gain to the stopped gain, the input to the actuator for driving the load becomes discontinuous.

Therefore, the shift of the load to the stopped state becomes oscillating and the positioning time becomes long.

Therefore, conventionally, as shown in FIG. 3, the gain during operation is changed at a constant rate from the gain during operation to the gain during stop.

FIG. 4 is a block diagram showing a conventional servo mechanism for doing this. To explain this, the actual position value from the actuator a that drives the load is constantly detected by the sensor b, and this is fed back from the command generator c to the summing point f of the output line of the target value toward the actuator a. .

The deviation E between the target value and the feedback value at the summing point f is the product of this and the gain K _A during operation K _A ·
It is outputted to a gain setting line c _{1 in} operation which takes E and a gain setting line c _{2 in} stop which takes a product K _B · E of the gain K _{B in} stop. Both lines c ₁ and c ₂ are selectively connected to the actuator a by a changeover switch e.

The changeover switch e is changed over by the changeover device d, and the changeover device d is determined to be the final positioning position based on the target value from the command generator c and the feedback value from the sensor b which are input to the changeover device d. At that time, the operating gain setting line c ₁ is switched to the stopped gain setting line c ₂ , and the gain to be applied to the actuator a is switched from the operating gain K _A to the stopping gain K _B.

At this time, the switch d further sequentially switches the stopped gain K _B to the final stopped gain at a fixed rate for a fixed time.

Specifically, each time a unit time elapses after the determination of the final positioning position, the gain K _Bi-1 during the previous stop and the final gain during the stop from the gain during operation. The gain during stop is updated to be the current gain K _Bi during stop by a value that takes into account a constant α representing the amount of change required per unit time up to a certain gain.

This can be expressed by the following equation (1).

K _Bi = K _Bi-1 + α −−−−−−−−−−− (1) K _Bi : gain at the i-th stop, but α = (K _Be −K _A ) / t · Δt K _A : Gain during operation K _Be : Gain during final stop t: Switching time Δt: Sampling time

[0014]

However, it is still insufficient to switch from the operating gain to the stopped gain at a constant time and at a constant rate as in the conventional case.

Consider now that the target acceleration / deceleration is changed from a high value shown by A to a low value shown by B as shown in FIG. 2 (a).

The switching time (t) in the conventional method is set so that, in the case of a high acceleration / deceleration A, a smooth change as shown in FIG. 2 (b) corresponding to the high acceleration / deceleration A can be obtained. Suppose you have set it.

In this case, if the target acceleration / deceleration is lowered from the acceleration / deceleration A to the acceleration / deceleration B, the approach of the load to the target position becomes slow. That is, the way the deviation E decreases decreases. On the other hand, the actual gain switching time is shown in FIG.
Since the same time t as described above is maintained as shown in correspondence with the low acceleration / deceleration B, the result is substantially the same as that when the gain is changed rapidly. Therefore, the gain input to the actuator changes abruptly, becomes discontinuous, and the transition to the stopped state tends to be oscillating, and is easily affected by disturbance.

In order to deal with this, the gain switching time must be sequentially changed according to the target acceleration / deceleration and the state of disturbance. When lowering the target acceleration / deceleration as in the above example, it is necessary to lengthen the switching time.

However, even when the gain switching time is sequentially set corresponding to the change in the target acceleration / deceleration, the characteristic equation of the system is not simple and involves trial and error again, so that much labor and time are required. Is. Also, it is difficult to deal with unexpected disturbances.

If an attempt is made to cope with this by setting the switching time corresponding to the low acceleration / deceleration, there is a problem that the time is unnecessarily long in the case of the high acceleration / deceleration.

[0021] Therefore, the present invention has an object to solve the above problems, and responds to a change in the target acceleration / deceleration or a disturbance in real time to position the load when the target acceleration / deceleration is high. An object of the present invention is to provide a gain switching device for a positioning servo mechanism that can be stably performed without wasting time.

[0022]

In order to achieve the above-mentioned object, a gain switching device for a positioning servomechanism of the present invention operates a load to a target value based on a deviation between a target value of a load and a feedback value. In the gain switching device of the positioning servo mechanism that switches the operating gain to the stopped gain when the load reaches the final positioning position, each predetermined time after the gain switching time. In the product of the deviation and the final gain during stoppage, the difference between the product of the deviation and the feedback value of the gain set at a predetermined time point before each predetermined stoppage time is taken in, and It is characterized in that a control means for updating the gain is provided.

[0023]

In the above structure of the gain switching device for the positioning servomechanism of the present invention, when the load reaches the final positioning position, the control means operates to switch the operating gain to the stopped gain. , At each predetermined time point after the time point, during the stop set at a predetermined time point before the deviation and the product of the deviation of the target value of the load and the feedback value and the final gain during stoppage The difference in the product with the feedback value of the gain of is taken in and the gain during the stop is updated, and the difference of this product represents the actual approach state of the load to the target position according to the acceleration / deceleration of the target of the system Since it reflects the gain during stop, even if the target acceleration / deceleration changes or there is an unexpected disturbance,
These can be dealt with in real time.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A gain switching device for a positioning servo mechanism as an embodiment of the present invention will be described below with reference to FIGS.

In the apparatus of this embodiment, as shown in the block diagram of FIG. 1, the value of the actual position of the actuator 1 for driving the load is constantly detected by the sensor 2, which is directed from the command generator 3 to the actuator 1. It is fed back to the combining point 6 on the output line of the target value.

The deviation E between the target value and the feedback value at the summing point 6 is a gain setting line 3a in operation which takes a product K _A · E of this and the gain K _{A in} operation, and the gain is being stopped. is the output of the gain setting line 3b in stop taking the product K _B · E between the gain K _B, the two lines 3a, 3b are to be connected alternatively switched to the actuator 1 by the change-over switch 5 There is.

Further, the changeover switch 5 is changed over by the changeover device 4, and the changeover device 4 is considered to be the final positioning position by the target value from the command generator 3 and the feedback value from the sensor 2 which are inputted thereto. When the determination is made, the changeover switch 5 is switched from the operating gain setting line 3a to the stopped gain setting line 3b so that the gain applied to the actuator 1 is switched from the operating gain to the stopped gain.

In the present embodiment, in particular, at each predetermined time point after the determination time, the gain setting line 3b in the stopped state is _added to the product K _Be · E of the deviation E and the final gain K _{Be in the} stopped state, The stopped gain K _B is calculated by the difference of the product K _Bi-x · E between the deviation E and the feedback value K _Bi-X of the stopped gain set at a predetermined time point before each of the predetermined time points. An update gain setting line 3c for updating is provided.

As the feedback value K _Bi-x , the feedback value of the gain during stop set at each predetermined number of previous times may be used in any way, and may be determined according to various actual conditions. . In the case of this embodiment, the gain K _Bi-1 during the previous stop is used. More specifically, the input U of the gain K _Bi-1 in the last stop, the actuator 1 which is the product K _Bi-1 · E of the difference E calculated from the gain K _Bi-1 in the last stop Input U to the actuator 1, which is K _Be · E calculated from _Bi-1 and the final gain K _Be during stop.
_The value obtained by multiplying the difference from _Be by the constant β shown in the conventional example is added, and the result of this addition is the gain K _Bi during the current stop.

If this is expressed by an equation, the following equation (2) is obtained.

K _Bi = K _Bi-1 + β · (U _Be −U _Bi-1 ) −−−−− (2) K _Bi : i-th stopped gain U _Be = K _Be · E U _Bi = K _Bi · E Here, in order to facilitate comparison with the case of the conventional example described above, consider a case where the target acceleration / deceleration is changed from a high acceleration A to a low acceleration B as shown in FIG.

In the present embodiment, at a predetermined time point before the deviation E and each predetermined time point with respect to the product U _Be of the deviation E between the target value of the load and the feedback value and the final gain K _Be during stop. Feedback value K of the set gain during stop
Captures differences in product U _Bi-x and _Bi-x, by updating the gain K _B suspended at each predetermined time point, the target of the load difference between this product is in accordance with the acceleration and deceleration of the target system The actual approach to the position can be reflected in the gain during stop.

Specifically, when the target acceleration / deceleration is high,
The load gets closer to the target position. In other words, the difference in the product difference decreases quickly. Conversely, if the target acceleration / deceleration is low,
The load approaches the target position slowly, and the difference in the product decreases slowly.

Therefore, if the difference in the product is reduced quickly, the gain during stop is also fast and approaches the final gain,
If the difference between the products decreases slowly, the gain during stop will slowly approach the final gain, and the input to the actuator 1 will change accordingly.

As a result, as shown in FIG. 2 (c), when the target acceleration / deceleration is as high as A or as low as B, the gain during stop changes continuously and smoothly. Therefore, positioning control can be achieved in a stable manner in response to changes in acceleration / deceleration, and without wasting time when the target acceleration / deceleration is high. Can also respond in real time.

[0036]

According to the gain switching device of the positioning servomechanism of the present invention, the target of the system is used to update the gain while the load is stopped at each predetermined time after the load reaches the final positioning position. The element that represents the actual approaching state of the load to the target position according to the acceleration / deceleration of the vehicle is reflected in the gain during stop, and even if the target acceleration / deceleration changes or there is an unexpected disturbance, the real time Since it can handle these, the positioning control can be achieved stably and with high accuracy, and there is no wasted time when the target acceleration / deceleration is high, and positioning can always be performed as quickly as possible. it can.

[Brief description of drawings]

FIG. 1 is a block diagram showing a positioning servo mechanism having a gain switching device as an embodiment to which the present invention is applied.

FIG. 2 is a comparative explanatory diagram of a conventional technique and an embodiment of the present invention when a target acceleration / deceleration changes.

FIG. 3 is an image diagram of a gain switching state by a gain switching device of a conventional positioning servo mechanism.

FIG. 4 is a block diagram showing a positioning servo mechanism having a conventional gain switching device.

[Explanation of symbols]

 1 Actuator 2 Sensor 3 Command generator 3c Update gain setting line 4 Changer 5 Changeover switch 6 Addition point

Claims (1)

[Claims] 1. When operating the load up to the target value based on the deviation between the target value and the feedback value of the load, when the load reaches the final positioning position, the operating gain is changed to the stopped gain. In a gain switching device for a positioning servo mechanism that is switched, at each predetermined time point after the gain switching time, from the deviation and each predetermined stop time point with respect to the product of the deviation and the final stopped gain A gain switching device for a positioning servomechanism, comprising a control means for taking in a product difference between a gain and a feedback value set at a previous predetermined time point and updating the stopped gain.