SU1576881A2 - Nonlinear correcting device - Google Patents

Abstract

The non-linear correction device relates to automatic control, is intended to improve the dynamic characteristics of the automatic control system, in particular, drives of industrial robots and computer numerical control machines, and is an improvement on the known device by author. N 1120276. The purpose of the present invention is to improve the accuracy and speed of the device. The goal is achieved by controlling the transmitting ratio of the device amplifier, which allows one to purposefully change the instant of switching of the corrected system from negative feedback to positive and thereby increase its speed with varying parameters. The transient of the system with each step of tuning the gain of the amplifier approaches the process with maximum speed and without overshoot. 7 il.

Description

The invention relates to automatic regulation, is intended to improve the dynamic characteristics of automatic regulation systems, and is an improvement of the device according to aut. No. 1120276.

The aim of the invention is to improve the accuracy and speed of the device.

Figure 1 shows the block diagram of the proposed device; 2 and 3, phase trajectories explaining the operation of the device; figure 4 is a block diagram of a peak detector; Fig. 5 shows a circuit diagram for resetting a peak detector; in Figs. 6 and 7, voltage diagrams explaining the operation of the device.

The device contains an amplifier 1, a module 2 determining module, a unit 3 multiplying, the first peak detector 4, the scaling unit 5, the first adder 6, the signal-relay 7, the zero-organ 8, the second adder 9, the second peak detector 10, the comparator 11, driver 12 pulses, element OR 13, reversible counter 14, block 15 of the initial installation of the counter, peak detector 16 positive values, peak detector 17 negative values, adder 18, source 19 positive supply voltage, source 20 negative supply voltage, capacitors 21 and 22, tr nzistory 23-25, optocouplers 26 and 27, resistors 28-31, a tire 33 total devices.

cd j

ZE

00 Ab

to

Amplifier 1 is controllable. In the initial state, it has a transfer coefficient K defined by a code recorded in the reversible counter 14 with the help of block 15 of the initial installation of the counter. Each pulse arriving at the summing input of the reversible counter 14 increases its content, which leads to an increase of 4K in the gain of amplifier 1. The gain becomes equal to K hDe n, the number of pulses received at the summing input of counter 14.

Each pulse arriving at the subtracting input of the reversible counter 14 reduces its content, which leads to a decrease in D K of the gain of amplifier 1. The gain becomes equal to K - where n is the number of pulses received at the sub input of the reversible counter.

Peak detectors 4 and 10 are bi-directional. As a reversible counter, any counter, such as a binary one, can be used.

Consider the work of the corrective device on the phase plane (Figures 2 and 3) using the example of a second-order system with a transfer function

W (P)

R (Tr + 1)

where K0, is the transmission coefficient of the open-loop system corrected by this device, without taking into account the transmission coefficient of the correction device; K - transfer coefficient correction device.

Since the correction device only changes the sign of the feedback, the characteristic equations for positive and negative feedback in the system are written as

 5L-0; tf + -L -fl + IS

1 f

ABOUT

0

The first case is characterized by the presence of two phase trajectories in the form of direct 33, passing through the origin of coordinates with angular coefficients equal to the root of the characteristic equation fl, 0, g O. In the second case at 4К0Т. 1, the phase trajectories have the form of twisting spirals — 34 and 35. In the initial state, negative feedback is included in the system. The initial values of the transmission coefficient of the amplifier 1 and the transmission ratio of the scaling unit 5 are set such that the control system provides a process without overshoot with the required speed.

The output signal of amplifier 1 is converted by unit 2 of determining the module to unipolar. In block 3 of multiplication, the sign is assigned to the output signal of block 2 of the module definition,

5 The initial conditions are set on the phase plane (X and X phase coordinates) by the point N. Movement occurs along the phase trajectory Nd (figure 2). The first peak detector 4 stores the extreme XQA value of the input signal X of the correction device. The first adder 6 compares the current value of the input signal of the device with its memorized extreme value, converted by the scaling unit 5. If the transfer coefficient of the scaling unit 5 is critical, the point d of reaching equal X t-X01 equals the direct slope of ft 2 . At point d, the positive feedback of the system is turned on, and the movement proceeds along this line. The system is also very fast in the absence of overshoot.

Changing the system parameters for a given transfer coefficient of the scaling unit 5 leads to an improvement in the transient process (phase trajectories 34 and 35 in Figures 2 and 3, respectively). If such a change in the parameters of the control system occurred such that the transfer coefficient of the scaling unit 5 becomes higher than the critical one, then the movement from point N goes along a spiral trajectory to point a4, which belongs to the straight line with the slope | C, | g.

five

0

five

At point a, equality holds.

X wx

0) and is included positive

X02 is inversely connected to the system. Movement occurs to the point XQ2 along the section of the hyperbola. During this time, the output of the second adder 9 increases in magnitude and the input signals of the comparator I1 are equal. At the point, the signal of the second adder 9 reaches an extremum and begins to decrease in magnitude. At this point, a voltage drop appears at the output of the comparator 11, from which the driver 12 forms a reset pulse for the first 4 and second 10 peak detectors. The reset pulse also arrives at the summing input of the reversible counter 14, increasing its content, thereby increasing the gain factor of amplifier 1 by DC.

After resetting, the peak detectors 4 and 10 store the current values of the input signal of the device and the output signal of the second adder 9, respectively. In the system, the negative feedback of the system is turned on and the movement from point X to point a, which belongs to the straight line with the angular coefficient | C2 | 7 | C, |, occurs along a section of the spiral-like phase trajectory. At point a, the positive feedback of the system is turned on again, and the process is repeated until the input signal of the correction device becomes zero. At the same time, with each switch from the positive to the negative side, the communication of the system results in a further increase in the content unit of the reversible counter I4 and, as a result, an increase in the gain of amplifier 1 per DC, which provides a stepwise approximation of the transition process to the best for the changed system parameters Fig. 2 shows the phase transition trajectory 34 of the system with a dashed line without changing the transmission coefficient of amplifier 1.

If the parameters of the system being adjusted have changed so that the value of the transfer coefficient of the scaling unit 5 becomes less critical, then the transition process is oscillatory in nature (Fig. 3, phase trajectory 35. And phase trajectory 33 for a critical value

157688

transfer coefficient of the scaling unit 5).

In the initial state, negative feedback of the system is included. With the change of parameters under consideration, the motion in the system occurs from point N along a helical phase trajectory. The first peak detector 4 remembers the extreme value

X signal

01

When performing at

five

0

five

and, belonging to a straight line with an angular coefficient, the equality X ttX- includes the positive feedback of the system. Further, before changing the sign of X, the motion passes through the section of the hyperbola. At point b, the null organ 8 generates a pulse that flushes the first 4 to the second 10 peak detectors and simultaneously reduces the contents of the reversing counter 14, which leads to a decrease in the gain gain I on the DC. The system turns on the negative feedback and moves along spiral phase trajectory 34. The first peak detector 4 stores the next extreme value of the input sig0

five

0

five

0

five

Nala X

ov

At the moment of equality X m X

But on (dot), the next positive feedback of the system occurs. At the same time, the point aa belongs to the straight line with the slope | C, j. In the following, the process is repeated. There is a step-by-step approach of the transition process to the best for the changed system parameters. This reduces the oscillation and increases the speed of the corrected system.

Using new: elements of the reversible counter 14 and the block 15 of the initial installation of the counter to control the transfer ratio of amplifier 1 distinguishes this correction device from the known one. as it allows an increase in the speed and accuracy of the system under the conditions of changing its parameters, and a transition process is provided that approaches the process step by step without overshoot. Testing the next action with constant values of the system parameters, the correction device provides with the greatest speed and without overshoot.

Claims (1)

Invention Formula Nonlinear correction device according to auth.St. No. 1120276, characterized in that, in order to improve the accuracy and speed of the device, a reversible counter and a block on the initial installation of the counter, connected by the outputs to the installation inputs of a reversible counter connected by a summing input to the output of the pulse former, the subtractive input to the output of the zero-organ, and the outputs to a group of amplifier control input inputs. 1 FIG. g N Hogh fflXoi XH J5 Ґig.CH N Fig.Z FIG. five