CN102540880B - Quick and stable tracking control method in servo turntable system - Google Patents

Abstract

The invention provides a quick and stable tracking control method in a servo turntable system, which is mainly used for realizing the quick overshooting-free tracking of a control system of a servo turntable, especially tracking positioning with a large angle. The invention particularly relates to a control strategy based on an if-else-end rule. A design formula of a controller is obtained by utilizing the maximum angular speed and the maximum angular acceleration of the control system of the servo turntable and a maximum angle needing to be positioned. In order to achieve the aims that the requirements of high speed and high stability are met and high accuracy can also be obtained, a proportional controller and a proportion integration (PI) controller are combined into one control strategy by adopting the if-else-end rule, and the switching conditions of the controllers are determined by the overshooting quantity. The quick and stable tracking control method in the servo turntable system is simple and effective, and engineering is easy to realize.

Description

Quick and stable tracking and controlling method in a kind of servo turntable system

Technical field

The invention belongs to turntable control field, be specifically related to quick and stable tracking and controlling method in a kind of servo turntable system, be mainly used in realizing control system fast, non-overshoot follows the tracks of, the especially track and localization of wide-angle.

Background technology

Realize turret systems fast, the Tracking Control Strategy of non-overshoot, conventionally adopt fuzzy control or intelligent control technology.Generally will utilize error, error rate and other signal to set up complicated logic and judge that rules realize control strategy, the judgment rule how establishing is obviously very important.For the rotating platform control system that needs wide-angle track and localization, adopting the Bang-Bang control based on optimal time is a kind of extraordinary method.But the cut-in timing that how to confirm Bang-Bang controls is extremely important, is also very very difficult.

Summary of the invention

The technical problem to be solved in the present invention is: overcome the deficiencies in the prior art, propose quick and stable tracking and controlling method in a kind of servo turntable system.The speed, acceleration and the maximum orientation angle design control strategy that make full use of rotating platform control system, described method is simple, reliable and stable, has improved rapidity and the accuracy of turntable control wide-angle track and localization.

The technical solution used in the present invention is: quick and stable tracking and controlling method in a kind of servo turntable system, and the method concrete steps are as follows:

The first step, maximum operating speed and the maximum functional acceleration of actual test servo turntable system, and obtain concrete numerical value and be designated as respectively V _max, a _max;

Second step, making U (k)=Ke (k) is positioner, and wherein U (k), e (k) k moment are position control output and error, and K is controller gain; If

if P≤0.5P _maxcarry out the 3rd step, after execution the 3rd step, carry out the 5th step; Otherwise the 4th step is carried out in redirect, after execution the 4th step, carry out the 5th step; Wherein, P _maxthe maximum angle scope that may locate for needs;

The 3rd step,

wherein Δ t is the position control sampling time;

The 4th step,

wherein Δ t is the position control sampling time;

The 5th step, the maximum angle scope P locating according to the 3rd step or the controlled device gain of the 4th step K _maxfor requiring, in actual servo turret systems, adopt controller U (k)=Ke (k), carry out closed loop test; Vernier control device gain K, by closed loop overshoot control in 0.01 °;

The 6th step, according to conventional Frequency Design method, designs a PI controller, and overshoot is no more than 10%.

Preferably, described the 5th step, the controller of the 6th step adopts if-else-end rule to be combined into a control strategy; Specific as follows:

If (| e (k) | > e ₀) carry out controller U (k)=Ke (k) described in the 5th step

PI controller described in Else execution the 6th step

End

Wherein, e ₀=0.01 °/10%=0.1 °.

The beneficial effect of the present invention compared with existing technical method is:

(1) the present invention sets up the mathematical formulae of maximal rate, maximum angular acceleration and maximum orientation angle, and design considerations is provided;

(2) adopt if-else-end rule to combine simple ratio and PI controller, method is simple and reliable;

(3) control system have fast, steadily, non-overshoot, high precision feature.

Accompanying drawing explanation

Fig. 1 is that desirable speed moving law: Fig. 1 (a) turntable reaches maximal rate; Fig. 1 (b) turntable does not reach maximal rate;

Wherein: V _maxfor turntable maximal rate; t ₀for turntable accelerates to time of maximal rate from zero velocity;

T ₂for turntable is from maximal rate to the moment of slowing down; t ₃for the theoretical time of turntable wide-angle operation;

T ₄for turntable accelerates to speed V ₁time; t ₅for the theoretical time of turntable low-angle operation;

Fig. 2 is that turntable wide-angle is followed the tracks of: the angle change in location curve of Fig. 2 (a) turntable; The speed change curves of Fig. 2 (b) turntable;

Wherein: Fig. 2 is described is 180 ° of actual rules of turntable operation; Position recording frequency is 100Hz, and speed record frequency is 400Hz;

Fig. 3 is that turntable low-angle is followed the tracks of: the angle change in location curve of Fig. 3 (a) turntable; The speed change curves of Fig. 3 (b) turntable;

Wherein: Fig. 3 is described is 30 ° of actual rules of turntable operation; Position recording frequency is 100Hz, and speed record frequency is 400Hz.

Embodiment

Below in conjunction with the drawings and specific embodiments explanation the present invention, the content that those skilled in the art can disclose according to this instructions is understood effect of the present invention and advantage.

Fig. 1 has provided servo turntable speed closed loop rule in the time following the tracks of, and in the time of wide-angle track and localization, can obtain the time of turntable operation:

$t_3=2\frac{V_{\max }}{a_{\max }}+(P_{\max }-\frac{V_{\max }}{a_{\max }}*V_{\max })/V_{\max }---\left(1\right)$

In the time of smaller angle track and localization, can obtain the time of turntable operation:

${\mathrm{<figure-callout\; id="5"\; label="t"\; filenames="HDA0000133968620000031.png"\; state="\{\{state\}\}">t</figure-callout>}}_5=\sqrt{2\frac{P_{\max }}{a_{\max }}}---\left(2\right)$

Maximal rate, the peak acceleration of test table can be carried out under speed closed loop.Servo turntable control system generally all has speed closed loop, in work, all can limit speed, and maximum speed limit is V _max.Peak acceleration method of testing: give step of Speed closed-link system, record the rise time, peak acceleration a _maxequaling given step value was removed in the rise time.

The control strategy of track and localization is exactly to design tracking control unit on the basis of speed closed loop.Proportional controller U (k)=Ke (k) has the feature of quick response, how to obtain ride gain, and method is as follows: first need to, in location, judge whether control system can reach maximal rate, and formula is as follows:

$P=\frac{V_{\max }}{2a_{\max }}*V_{\max }---\left(3\right)$

If P≤0.5P _maxshow that control system is bound to reach maximal rate; Otherwise, can not reach maximal rate.From Fig. 1, can obtain, adopt the constraint condition that controller U (k)=Ke (k) turntable slows down to be:

Reach maximal rate: $\frac{V_{\max }-K*P}{\mathrm{\&Delta;t}}\&le;a_{\max };$

Do not reach maximal rate: $\frac{\sqrt{a_{\max }*P_{\max }}-K*0.5P_{\max }}{\mathrm{\&Delta;t}}\&le;a_{\max },$

Wherein Δ t is the position control sampling time, so can determine controller gain K

Whether be rationally necessary, this is mainly because ignore the impact of speed closed loop here if carrying out test controller U (k)=Ke (k) at real system, and this factor K that conventionally makes to gain is more smaller than actual computation.The principle of debugging: closed loop overshoot control is in 0.01 °.Only adoption rate controller is inadequate, and this is main because there is no the participation of integral controller, and system can not obtained high precision.Do not consider any impact of step above, according to conventional Frequency Design method, design a PI controller, overshoot is no more than 10%.Adopt if-else-end rule that aforementioned proportion and PI controller are combined into a control strategy.Specific as follows:

If (| e (k) | > e ₀) carry out controller U (k)=Ke (k) described in the 5th step

PI controller described in Else execution the 6th step

End

Wherein, e ₀=0.01 °/10%=0.1 °.

So just realize control strategy of the present invention.Concrete embodiment provides as Fig. 2,3.The servo turntable control system of supposing a speed closed loop, position open loop characteristic is as follows:

$G\left(s\right)=\frac{1}{s(s+150)}---\left(4\right)$

Maximal rate is 100 ⁰/ s, peak acceleration is about 300 ⁰/ s ².The maximum angle that needs track and localization is 180 °, and calculating proportional controller by method is above U (k)=5.8e (k).In system, by test, being met the ride gain of closed loop overshoot control in 0.01 ° is K=5.7.PI controller is

control strategy is like this:

if(|e(k)|＞0.1)

U(k)＝5.7e(k)

Else

$G\left(z\right)=\frac{20(1-{0.985z}^{-1})}{(1-z^{-1})}$

End

Carrying out 180 ° of needed theoretical times of angular range is 2.13s, and in 2.13s left and right, systematic error has arrived within the scope of 0.01 ° as shown in Figure 2.

Still utilize this control strategy, carry out the result of 30 ° of angular ranges and can know as Fig. 3: systematic error has arrived within the scope of 0.01 ° in 1.1s left and right.

From implementation method above and use example can know rationality and the engineering validity of control method of the present invention.

Claims (1)

1. a quick and stable tracking and controlling method in servo turntable system, is characterized in that: the method concrete steps are as follows:

The first step, maximum operating speed and the maximum functional acceleration of actual test servo turntable system, and obtain concrete numerical value and be designated as respectively V _max, a _max;

Second step, making U (k)=Ke (k) is positioner, and wherein U (k), e (k) they are the output of k moment position control and error, and K is controller gain; If if P≤0.5P _maxcarry out the 3rd step, after execution the 3rd step, carry out the 5th step; Otherwise the 4th step is carried out in redirect, after execution the 4th step, carry out the 5th step; Wherein, P _maxthe maximum angle scope that may locate for needs;

The 3rd step,

wherein Δ t is the position control sampling time;

The 4th step,

wherein Δ t is the position control sampling time;

The 5th step, the maximum angle scope P locating according to the 3rd step or the controlled device gain of the 4th step K _maxfor requiring, in actual servo turret systems, adopt controller U (k)=Ke (k), carry out closed loop test; Vernier control device gain K, by closed loop overshoot control in 0.01 °;

The 6th step, according to conventional Frequency Design method, designs a PI controller, and overshoot is no more than 10%;

Described the 5th step, if the controller of the 6th step adopt if-else-end-otherwise-end rules is combined into a control strategy; Specific as follows:

If If is | e (k) | >e ₀, carry out controller U (k)=Ke (k) described in the 5th step;

Otherwise carry out PI controller described in the 6th step Else;

End finishes;

Wherein, e ₀=0.01 °/10%=0.1 °;

The concrete servo turntable control system for a speed closed loop, position open loop characteristic is as follows:

$G\left(s\right)=\frac{1}{s(s+150)}$

Maximal rate is 100 ⁰/ s, peak acceleration is about 300 ⁰/ s ²the maximum angle that needs track and localization is 180 °, and calculating proportional controller by method is above U (k)=5.8e (k), passes through test in system, being met the ride gain of closed loop overshoot control in 0.01 ° is K=5.7, and PI controller is

control strategy is like this:

If If is | e (k) | >0.1,

U(k)＝5.7e(k)

Else otherwise

$G\left(z\right)=\frac{20(1-{0.985z}^{-1})}{(1-z^{-1})}$

End, finishes;

Carrying out 180 ° of needed theoretical times of angular range is 2.13s, and in 2.13s left and right, systematic error has arrived within the scope of 0.01 °.

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