SU836638A1 - Device for reproducing functions of two variables - Google Patents

Description

The invention relates to analog computing and can be applied in the simulation of automatic control systems. A device for reproducing the functions of two variables ij is known, which contains functional converters of one variable, the inputs of which are connected to the input of the device linear elements by a reference voltage. This device is intended to multiply produce functions approximating parallel sections of broken lines, which limits the class of reproducible functions. The closest technical solution to the invention is a device for reproducing the functions of two L2J variables, containing functional converters of one variable and a functional converter with variable reference voltages, the inputs of which reference voltage are connected through linear elements with linear characteristics. with the first input of the device, the input of the functional converter with variable reference voltages is connected to the second input of the device, and the output is connected to the first input output adder, multipliers and an additional adder, the first input of which is connected to the output of the first power supply unit, the second input to the reference voltage bus, and the output to the first input of the second multiplication unit. The second input of the second multiplication unit is connected to the outputs of the first functional converter, the output of the second multiplication unit is connected to the second input of the output adder. The first input of the first multiplication unit is connected to the first input of the device via the second functional converter. The drawback of the device is the low accuracy of reproduction of the functions of two variables, which is due to the replacement of nonlinear characteristics of change.

yaklonov. plots of approximation by linear characteristics.

The chain of the invention is to improve the accuracy of the operation of the us;

This goal is achieved by the fact that the device for the reproduction of functions of two variables, containing the adder, the first subtraction unit, the first and second functional transducers, three multiplication units, the output of the first of which is the output of the device, and its inputs are connected respectively to the outputs of the first functional transducer and adder, the first input of the adder is connected to the first bus of the reference voltage, and the second input is connected to the output of the second multiplication unit, the inputs of the second multiplication unit are connected, respectively, to the output The second functional converter and the output of the first subtraction unit, the first input of which is the first input of the device and the second input connected to the second bus of the reference voltage, the inputs of the first and second functional converters connected and the second input of the device, contains the analog key, the third functional converter , second and third subtraction blocks. The inputs of the second subtraction unit are connected respectively to the outputs of the second and third functional transducers, and the output is connected to the first input of the third multiplication unit, the second input of which is connected to the output of the third subtraction unit. The output of the third multiplication unit is connected via an analog key to the third input of the adder, the inputs of the third subtraction unit are connected respectively to the third bus of the reference voltage and to the first input of the first subtraction unit, and its output is connected to the control input of the analog key. The input of the third (} unction converter is connected to the input of the first functional converter.

FIG. 1 shows a block diagram of the device; in fig. 2 - an example of approximation of a family of curves of functions of two variables f (X,).

The device for reproducing functions of two variables contains functional transducers 1-3, multiplication blocks 4–6, subtraction blocks 7–9, analog key 10, the output of which is connected to the input of adder 11; One of the inputs of the adder 11 is connected to the reference voltage bus 12, the second inputs

The subtraction blocks 7 and 9 are connected to the reference voltage buses 13 and 14, respectively, and the first Inputs are connected to the first input of the device 15. The inputs of the 1, 2, 3 converters are connected to the second input of the device 16.

The device for reproducing the functions of two variables works as follows.

A piecewise-linear approximation of the f (x, Nj, 0) curve, which limits the range of the function f (V) (Fig. 2) and has the greatest slope in the variable x, is preliminarily performed.

For the remaining curves, the families adopt the same law of splitting, since the steepness of the section of all curves does not exceed the slope of the corresponding section of the curve (iVo). Then, the family of curves K (X, V) of the slope of each approximating region is determined depending on a variable, which is represented by a family of linearly broken lines.

K, (, V).

This family can be represented by an analytical expression:

b-tg | 5 (x) (i / -v / o) with

k (y,)

(one)

btgf | b () f (4-5lVpH: bgfjbCx)

—dependence of the coefficient of the slope of the direct (variable X with ij С vj;

tg (x)

-dependence of the slope of the straight line t () (i) on the variable X when

 v;

X

- break point of the family

K, M);

With a value of 5 /, the magnitude of the error in replacing the curves of the K (,) family with linear sections is maximal. Position of the point v / put (depending on the type of the function f (X, V}

The dependence ig (X) is reproduced by the second functional converter 2, and the dependence tg X C) by the third fuvial converter 3. To the input of the adder 11, bus 12 is supplied with a reference voltage representing the corresponding scale.

Claims (2)

The dependence -tg 2 (() (fV) is obtained at the output of multiplication unit 6, and the dependence tgfjb (x) (Y () is at the output of multiplication unit 5. At Y 4, the voltage at the output of subtraction unit 9 has a positive sign, and the key 10 is open. In this case, the voltage at the output of the adder 11 corresponds to the expression (1) at. If VJ 7 is then the voltage at the output of the subtraction 9 changes the sign on the block A, the signal is shorted, the switch is the GO. adder 11 corresponds to the expression (1) with V The limiting curve f (X, Vo) is reproduced by the former 1, the output voltage of which is then multiplied on the multiplication unit 4 by the corresponding coefficient, V). The output voltage of the multiplication unit 4 thus obtained corresponds to a family of linearly broken ones (4 | VjJ, shown in Fig. 2. In preparing the function (c) for the reproduction path, the proposed device can The method of graphical approximation of functions or the computer-aided calculation of approximation parameters on a digital computer can be used. The proposed device allows to reproduce a wide class of functions of two variables, including functions with a sharp change in the slopes curves on both variables and has a high speed. The use of this device for reproducing a wide class of functions of two variables in the simulation of automatic control systems allows one to obtain a techno-electronic effect, consisting in a significant increase in the accuracy of reproduction of functions with a relatively simple structure of the device. Claims An apparatus for reproducing functions of two variables comprising an adder, a first subtraction unit, a first and a second functional transducer, three multiplication units, the output of the first of which is the output of the device, and its inputs are connected respectively to the outputs of the first functional transducer on the adder, first the sum of the mat- ter is connected to the first bus of the reference voltage, and the second one to the output of the second block of the voltage, while the hoops of the second multiplication unit are connected to the output of the second Functional converter and the output of the first subtraction unit, the first input of which is the first input of the device, and the second one is connected to the second bus of the reference voltage, the inputs of the first and second functional converters are connected and are the second input of the device, characterized in that In order to improve the accuracy of reproduction of functions, it contains an analog key, a third functional converter, a second and third subtraction blocks, the inputs of the second subtraction block are connected respectively to the outputs The second and third functional converters, and its output is connected to the first input of the third multiplication unit, the second input of which is connected to the output of the third subtraction unit, the output of the third multiplication unit is connected via an analog key to the third input of the adder, the inputs of the third subtraction unit are connected respectively to the third bus the reference voltage and to the first input of the first subtraction unit, and its output is connected to the control input of the analog switch,: the input of the third functional converter is connected to the input m of the first functional converter. Sources of information taken into account during the examination 1. USSR author's certificate 267196, cl. G 06 Q 7/26, 197O. 2. Authors certificate of the USSR 526919, cl. G About G 7/26, 1976 prototype).