SU1288651A1 - Adaptive servo system - Google Patents

Abstract

The invention relates to the field of automatic control and regulation of technological processes and is intended to track a useful input signal arriving at the input in a mixture with interference of variable intensity. The aim of the invention is to increase the accuracy and noise immunity of the system. Lent on the goal is achieved by the fact that in barely; a system comprising a switch 4, a stepping motor 5, a control object 6, a position sensor 7, a comparison element 2, an amplifier 3, a generator of 8 rectangular pulses, additionally connected in series are a nonlinear converter 10 and a driver 9 of control signals. The structural organization of the tracking system, based on the entered set of features, allows to increase the accuracy and noise immunity of the tracking system when tracking a variable speed input signal under the influence of a variable intensity disturbance. 2 hp f-ly, 7 ill. 1C (L with o oo as 05 SP

Description

one

The invention relates to automatic control and regulation of technological processes and is intended to track a useful input signal entering the input in a mixture with a variable intensity disturbance.

The aim of the invention is to improve the accuracy and noise immunity of the system.

Figure 1 is a block diagram of an adaptive tracking system; FIG. 2 is a block diagram of a control signal driver; FIG. FIG. 3 is a block diagram of a non-linear converter; in fig. 4 - input and output signals (a), error signal (b); on fig.Z - graphs of D

max

5 (5),

five

(KJ

(Kg) for- f 1 (5) Vg; ,, - 0.5

figure 6 is a graph depending on the parameters of the input signal; 7 is a graph of output versus converter code-to-converter input.

The block diagram of the adaptive tracking system comprises a control J, a comparison element 2, an amplifier 3, a switch 4, a shaking motor 5, a control object 6, a position sensor 7, a square pulse generator 8, a control signal driver 9, a nonlinear converter 10.

The block diagram of the control signal generator contains the amplitude-time converter 11, the first driver of the polarity signals 12, the first 13 and the second 14 logic gates, the first 15 and the second 16 inverting amplifiers.

The block diagram of the nonlinear converter contains the second shaper 17 of the polarity signals, a reversible counter 18, a register 19, a converter 20, a code-code, controlled frequency dividers 21 and 22.

The figures assume the following precepts; and - the output signal of the K-th element; © g, bd, - input and output useful signals; Vg and Vgyj; - input and output interference signals; X - error error signal.

The following system works as follows.

The setpoint signal le ,, + is fed to the second input of the comparison element 2, where it is compared with the output signal of the position sensor 7, the post

five

0

five

0

five

0

five

0

five

switch 4 comes on

the first input of the reference element. From the output of the element 2, the comparison of the error through the amplifier 3, the driver 9 of the control signals and (for example, the type BU-14D) stepper motor 5 (for example, the type of search PP-711). The amplified and formed error signal is processed by the stepper motor 5, the control object 6 changes its position so that the error is reduced.

When the input signal speed changes, the tracking error also changes, and for high input signal change rates, the system may have a large speed error.

The amplified error value from the output of amplifier 3 goes to the inputs of Shaper 9 and converter 10. Converter 10 calculates the duration of negative and positive error values x and realizes dT if (f) by their difference (Fig. 7). The generated frequency value {arrives at the second input of the imaging unit 9, where the signals arriving at the switch 4 are formed. The time interval of the positive and negative polarities and, in the first driver 12, the polarity signals are converted into positive polarity signals + and the outputs of the first driver 12 of the polarity signals are control for the valves 13 and 14, the second inputs of which receive the filling frequency f time interval.

Inverting amplifiers 13 and 16 amplify pulses up to -V (since existing switches require negative voltage to the Forward and Backward control inputs that go to switch 4. The first output of the driver 9 means control of the rotation of the engine 3 forwards (B), the second output back (H). Consequently, the driver 9, based on the error values, generates control signals, filled with a frequency from converter 10, of input 1

then to switch 4 to rotate the engine 5.

The amplified error signal U, at the input to the converter 10, in the second driver 17, polarity signals is converted into positive polarity signals: the corresponding outputs of the second polarity generator 17 + and -. If the error value is x; A reversible counter 18 performs a summation of frequency pulses f, arriving from frequency divider 22. If, then. the counter 18 will carry out, the subtraction of the pulses with the frequency f, and during the error period X in the counter 18 there will be a code corresponding to the difference

N

XiO

Counter 18 is porazr associated with

By register 19, which, on the leading edge of the output + of the second polarity signal generator 17, records the code obtained in the counter 18, the counter 18 is then reset to 0 and starts counting from the beginning.

The fixed difference code is transferred from register 19 to the converter 20; a code is a code that has a dependence of the output code on the input code, shown in Fig. 7. The signal of the second polarity signal generator + allows the conversion and the code for writing to the control frequency divider 21, which divides the frequency f depending on the division code applied to it. So, if the input signal is lagging behind, the difference () 0 and the frequency at the output of the divider 21 f is higher than the previous frequency f, which ensures a quick decrease in the tracking error of the input useful signal.

Let, for example, a useful signal at a certain section be approximated by a linearly growing function with an unknown growth rate: a) at; noise is a harmonic function with an unknown amplitude: VBX (t) bsincJO t. Transmitting to a stepping motor 5

W (P)

to

pdgp + i)

TO,

n. P -L- -n

(I)

 ... The engine output signal 5 is different.

is from the useful signal © p ,, (t) on

the magnitude of the displacement d, determined by the rate of change1 and the input useful signal, and by the magnitude of the amplitude of the disturbance at the output Vgj ,, (Fig. 4a). Dependence and and У „.„ On K, - looks like

U and V, from K

l x, - (2)

V,

6S

 -b)) sin (u) t -IP- + D) (3)

where A (i)) is the frequency response of the tracking system; H - phase shift;

1 5 Р

(four)

- gain factor

tracking system; u3 2 3ff is the interference frequency.

Maximum, the error has the following form:

.bA (u))

Figure 5 shows the dependences of the ICs), (.U.S (K). With a sufficiently large K, the tracking system will monitor the entire input signal, i.e., follow the noise, the magnitude of which in the output is: nominal signal will determine the main error. With a small K J, the error will be determined by the magnitude of the offset of the output useful signal from the input, these two opposite processes

in total, they give ec (K,) and)

the strand characteristic, which for some K has a minimum of the maximum error S. When you change the speed o. the desired signal or amplitude b of the interference of the graphs & (K j) will shift (Fig. 6). Therefore, it is worthwhile to control the value of K in order to achieve a minimum & . Information on the optimal value of K can be obtained by measuring the time difference between the existence of positive and negative tracking errors (Fig. 4b). Tracking error is

50

- V

OUT

(.B / t) in ()) - (e "Jt) (t) 0" x (t) + bsinoA 55

- (0Bx (t) -u) -b-A (u)). Sin (u) t-4) L-b AsinCu) t-4) - sinufcl l – b-C (u5 (sin (u) t -V),

where C (u)) / l + A4u)) - 2 A ())

V arctg A (uJ) sinH -lACiO) cos4 - Hence, in FIG. DB

s-%)

2oiu3;

 2dL.

X) u)

2 (71 -ci) u) - 2otuJ (5

dx - (x)

soL b,

- eleven

b C (ijO)

(6)

(7)

approximate

With (and))

l (iI))

(eight)

 231- 2. 2 ()

Then, substituting the expression (5), we get

.- 2 (| -) 2 S corresponds to

8 (l v) o,

  Mhvj

(8) in

a) -b-C (a))

(9)

Therefore, A (u)) l / b, (10)

and this corresponds to the case when

9. (t) + V -. ,, (t) is a positive BWXych

 maximum of Gn (t).

 | e1L

Determine what value of dT so we substitute

corresponds to

expression (10) in (9), we get

MIN

d1

Then lT 2 A (u)) / vnc (oJ). Substitute the expression (9) in (4)

(eleven)

S ..vZ (lt

out

Substitute the expression

5 (, + „)

yg

Thus, with two values

(13)

k

It has

SN 0

and

eight; 2D,

five

0

five

0

five

0

0

a this corresponds to the case of a positive maximum touching the output of the input useful signal.

Solving together expressions (13) and (}, we obtain the dependence K i (ur, however, to control Kg, having dependence (1), it suffices to change the pulse and in proportion to the frequency of the pulses f supplied to the switch input Then, in order to control the K stepper motor, a sufficient amount of supply — that is directly presented by the pro- cector — to change the frequency f of the dependence on d-t in Fig. 7.

Thus, in order to control the coefficient K, it is necessary to control the frequency f supplied to the switch, which varies with the magnitude (Fig. 7).

Indeed let f. will increase (the slope of the useful signal has increased). Then the magnitude of the tracking error l will increase, which will lead to the shift of the optimum to the right (Fig. 6), therefore, K needs to be increased. Considering FIG. 46 and FIG. 7, it can be seen that the magnification is about. therefore l, will reduce the difference and increase the frequency f. An increase in the amplitude of the noise b leads to

this optimum is shifted to the left (Fig. b). Therefore, Kg must be reduced 5 sew. Investigation of fig.4b and fig.7, it can be noted that -increasing k to increase the amplitude of the interference

and this in turn will lead to an increase in the difference in LT and a decrease in the frequency f, .B as a result of the optimum transmission coefficient of the engine 5 Kc is determined by the value of SL, the amplification of the amplitude is, (VICXKC

output, sietemy V, with

about yd

dit

max nk

the torus corresponds to the code in the reversible counter 18, by subtracting the number of pulses N transmitted to the N counting input of the counter 18 in the subtraction mode for x сO from the number N corresponding to the mode of additions 0;

dN

The reversible counter code captures AN when going from x O to x; It writes to the register 19. From the output of the register 19, the code goes to the converter, a code-code with the dependence shown in Fig. 7, and through the controlled frequency divider 21, the code of the converter 20 controls the change of frequency q in f, ensuring the setting of the optimal transmission coefficient which establishes in the tracking system a tracking mode with a minimum deviation of the output signal of the tracking system from the input useful signal.

Interference immunity of the servo system is also provided by the chosen method of converting the information about the optimal coefficient into the code of the control transmission coefficient of the actuator.

Thus, the proposed structure of the tracking system organization improves the accuracy and noise immunity of the tracking system when tracking a useful input signal with a variable speed in the field - the influence of the interference of the variable intensity.

Claims (3)

1. Adaptive tracking system, comprising a generator of rectangular pulses and a series-connected switch, a stepper motor, a control object, a position sensor, a reference element and an amplifier, the second input of the comparison element is connected to the output of the setter, characterized in that, in order to increase accuracy and noise immunity-. system, the nonlinear converter and driver of control signals are additionally connected in series, the first and second outputs of which are connected respectively to the first and second switch inputs, and the first inputs of the control signal generator ten 15 , - 25 20 thirty  , 35 40 45 50 The main input of the nonlinear converter is connected to the output of the amplifier, the second input of the nonlinear converter is connected to the output of the generator of rectangular pulses. 2. The system of claim 1, wherein the driver of the control signals comprises a series-connected amplitude-time converter, the first polarity driver, the first logic gate and the first inverting amplifier, the converter input amplitude - time is connected to the first input of the control signal generator, the second logic gate and the second inverting amplifier are connected in series, the first inputs of the first and second logic valves are connected to the output of the first one L polarity signal, and the second inputs are connected to their second input of the control signals, the inverting inputs of amplifiers connected respectively to the first and second output of the control signals. 3. Pop. 1 system, which differs from the fact that the nonlinear converter contains serially connected second polarity signal generator, reversible counter, register, converter code - a code, controlled frequency divider and frequency divider whose output is connected with a counting input of a reversible counter, the reset input of which is connected to one of the first outputs of the second polarization signal generator, the recording input of the register, the hystera and the control input of the converter is a code-code, and the input of the frequency divider is connected to the second output th nonlinear transducer controllable frequency divider output - with output the nonlinear transducer and the input of the second polarity signal shaper is connected with non-linear converter input. / 7 g 78  nineteen  go ten DiJ2.2 L g  go f / . 22  //, . fig.Z G1A a7b g. 4 Max f. jI-by s. 6th, About srig.5 , S, M, .6 bt (At.a,} Iff Iff %% FIG. B f.lf J. lH Compiled by I. Gvozdyova Editor A. Shandor Tehred V. Kadar Corrector I. Erdeyi Order 7805/45 Circulation 885 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4