SU384108A1 - DEVICE FOR MODELING LINEAR SYSTEMS - Google Patents

Description

one

The invention relates to modeling devices of linear systems and objects.

At present, one of the urgent tasks is the development of a device for modeling linear systems and objects according to their experimental dynamic characteristics. This is because the transient or impulse transition function is often known, and the equations of the object are unknown. In addition, the simulation of objects according to their experimental dynamic characteristics provides higher accuracy in reproducing dynamic properties.

Devices are known that are designed to reproduce the dynamic properties of linear systems and objects by their dynamic characteristics, which can be obtained both experimentally and by calculation.

Known modeling device containing a ring distributor, storage devices, keys, adders and resistors.

In such a device, each pure lag unit is implemented using four or five DC amplifiers. In connection with this, the use of this device leads to a complex circuit of a model containing a large number of constant-current amplifiers.

2

current, which significantly reduces the accuracy of reproduction of the dynamic properties of the system and complicates its operation.

The implementation of pure lag units at the infra-low frequencies inherent in automatic control systems and objects with large time constants is associated with technical difficulties, since this; it becomes necessary to use capacitors and resistors with large parameter values.

The low accuracy of the reproduction of the dynamic properties of the object being simulated and the instability of the work is caused by the drift of zero DC amplifiers.

Changing the time scale of the model in such a device entails the need for blocks of pure delay. All this significantly limits the scope of application of known modeling devices, does not provide high accuracy of the solution, and makes it difficult to prepare and use them.

The goal of the acquisition is to simplify the circuit design, increase the stability of the work, the accuracy of reproduction of the dynamic properties of the objects being modeled and improve the operational characteristics.

This is achieved by the fact that in the proposed device the input of the simulator

connected to the inputs of all memory blocks whose inputs through the resistors of their groups are connected to the inputs of the keys, as well as to the input of the first adder. The number of memory blocks, switches, resistors in the group, and the number of groups of resistors correspond to the number of cells in the ring distributor. The outputs of the keys and the output of the first adder are connected to the input of the second adder, the output of which is connected with the output of the simulator. The control input of each memory block is connected to the control input of the corresponding key and is connected to the output of one of the cells, and the control input of each subsequent memory block is connected with the output of the next cell of the ring distributor.

FIG. 1 shows a diagram of a modeling device.

The circuit contains a ring distributor /, cells 2i-2 "ring distributor, a generator of 3 clock pulses, memory blocks 4t-4p, keys 5i-5", resistors Ro, Ri-Rn of block 6i-6p of resistors, adders 7i and / 2.

FIG. Figure 2 shows the weight function Wi (t) of the object being simulated, displaced in the positive direction along the ordinate axis by the value - Woi, corresponding to the maximum negative value, where TW is the duration of the weight function.

FIG. 3 depicts voltage plots at various points of the simulator, where f / 2i - (- / 2 "are the voltage at the outputs of the cells of the ring distributor,

f / Bx is the input of the simulator, / 4, ,, - voltage at the outputs

memory blocks

1 (0 - n (t) - formed weight functions,

Woi-Won is the magnitude of the displacements of the generated weight functions Wi (t) - Wn (t), is the output signal of the simulator.

In the proposed device, the input t / i is connected to the inputs of the memory blocks. The output of the memory unit is connected through resistors i-Rn of its group to the inputs of the keys, and also through a resistor Ro to the input of the first adder 7i. The number of memory blocks, the number of keys, and the number of resistors in each group correspond to the number of cells in the ring distributor. The outputs of the keys and the output of the first adder are connected to the input of the adder / g, the output of which is connected to the output of the simulator. The control input of each memory block 4i and the control input of the corresponding key 5 are interconnected and connected to the output of the corresponding cell 2g of the ring distributor.

Modeling device works as follows.

From the outputs of the cells of the ring distributor, the pulses are t / 2, -1/2 ,; (Fig. 3) are fed to the control inputs of all memory blocks and keys. When a pulse is received from one of the cells to the control input of the corresponding memory block, the current value of the input signal C / j, x is stored, which is permanently applied to the input of all of the us blocks. The signal U ,, - / 74 "from the output of the memory blocks is fed through the resistors of its group to the inputs of the keys.

At each moment of time, only one key is opened, from the output of which the signal determined by the value of the resistor is fed to the input of the second adder. When preparing the task, the resistance values of the resistors of each group are set proportionally to the offset values of the ordinate axis Woi (Fig. 2) of the weight function of the modeling object at discrete equal times with a period equal to the pulse duration of the ring distributor cell. As a result, for the period T of operation of the ring distributor, during which the output value of the input signal is saved at the output of the memory unit using a group of resistors and switches included at the input of the second adder / 2, the weighting function of the simulated object is fixed, the beginning of which coincides with the moment of memory input signal (Fig. 3).

Simultaneously, the signal from the output of the memory unit through the resistor Ro and the adder 7; is fed to the input of the second adder 7z which ensures the subtraction of the components Woi (Fig. 2) and the formation of the output of the second adder of the weight functions of the simulated object of a given type (Fig. 2). After a period of operation of the ring distributor, which corresponds to the duration of the weighting function, the value of the input signal is memorized again and further the cycle of operation repeats.

All memory blocks and keys connected to their outputs through groups of resistors work in a similar way. However, due to the fact that the control inputs of the memory blocks and the control inputs of the keys are connected to the cells of the ring distributor with a shift, the weighting functions of the simulated object are stored at discrete equal time moments, shifted one relative to another Hia, the pulse width of the cell of the ring distributor. The sum of these weight functions, which is obtained at the output of the adder / 2, corresponds to the output signal of the OUT of the simulated object (Fig. 2).

If we assume that the shift interval tends to zero, then the convolution equation

Bb, xW-jX () (-), (1)

where o (0 - output signal;

(t) - input signal; W (t-m) is the weight function of the system, shifted in time by interval t, can be represented as a sum of the following form:

output (0 D J Bx (i А)) (- i А), (2)

where DT is the shift interval,

which is implemented by the proposed simulator.

Thus, the proposed simulator is built from simple blocks of the same type, its layout, setup and operation are simple. The device has a wide dynamic range, since it can work in the frequency range from infra-low frequencies to video frequencies, it has high accuracy of reproduction of the dynamic properties of the simulated systems and objects.

W; (t)

Subject invention

A device for simulating linear systems comprising memory blocks, resistor blocks, adders, keys and a ring distributor, characterized in that, in order to simplify the device and increase its accuracy, in it the outputs of the memory blocks are connected to the input of the first adder via blocks

resistors, the outputs of which are connected to one of the inputs of the keys connected via the second input to the first inputs of the memory blocks, the second inputs of which are connected to the input terminals of the device, the outputs of the keys

and the output of the first adder are connected to the input of the second adder, and the cells of the ring distributor are connected to the first input of the memory blocks.

20

72 th, 1

; I 2

t

F

 ; rm ..., -. . . .. ...

i- / ff / - /,.

iJ2Zw- - i- iJJxxlJx j: p2:: 2z2zzzz:,., ....., .. ,, ..

.LLiMjJ.L; JJJJj.rnTlTtt ..

..

-H

pTTxTTTTTTT lu