SU1312521A1 - Position control system for electric drive - Google Patents

Abstract

The invention relates to robotics and can be used in the construction of industrial robots manipulators. The aim of the invention is to improve the accuracy of the system. The goal is achieved due to the fact that the system has started the positioning start selection block, which operates in the predictive model of the electric drive and compares the roots of the velocity and positional equations of electric drive motion, solved in real time, based on the proposal that the speed of the electric drive is equal to zero. system mismatch. Depending on the results of the comparison, positive or negative control signals are applied to the drive input, as the relay control law is implemented. When creating a predictive model, the error signal, speed and setpoint value of the speed of the electric drive are used. 2 h. the item of f-ly, 4 ill. S (L with with N :) SP

Description

one

The invention relates to robotic technology and can be used for retracting industrial robot manipulators.

llcjb invention - new system accuracy.

FIG. 1 shows a functional system diagram; in fig. 2 - functional c. Block of the search for the beginning of positioning; in fig. 3 - functional diagram of the control signal generator; in fig. 4 - linear charts, according to the work of the search unit of the beginning of positioning.

The system comprises a setting device 1, a comparison unit 2, a control signal generator 3, a first source 4 of a constant signal, a first switch 5, a second source of a constant signal 6, a second switch 7, a current regulator 8, a power amplifier 9, an electric motor 10, working mechanism 1, position sensor 12, speed sensor 13, matching converter 14, positioning start selection block 15, third constant source 16, first integrator 17, first comparator 18, adder 19, second integrator 20, second comparator 21, element OR 22, one-shot 23, ele ment OR 24, element AND 25, RS-trigger 26, element AND 27, element 28 of the early values, elements AND 29-32, elements OR 33 and 34, fourth source 35 of a constant signal, current sensor 36, new, nerve , the second, third and fourth inputs 37-41 and the first and second outputs 42 and 43 of the forworld 3 control signal, the electric drive 44, the first, second and third inputs 45-47 and the first and second outputs 48 and 49 of the selector 15 start positioning.

The system can be implemented using both digital elements and analog elements. In the first case, the EVA1 with communication lines can be used as a setting unit, a digital comparison unit can be used as a comparison unit 2, a digital position sensor can be used as a position sensor 12, and a digital-analogue device as a matching device 14. develop; 1b. In the second case, all non-enumerated blocks are made analog. In addition to these, various intermediate modifications of the system with the use of a mixed digital-analog constructive implementation of these blocks are possible.

The positioning start selection unit 15 comprises an integrator 17, a comparator 18, an adder 19, an integrator 20, a room 21, an OR 22 element, a one-shot 23, an OR 24 element, an AND 25 element, an RS 26 trigger, and an 27 element.

about 5

0

50

The control signal generator 3 contains an equivalence element 28, AND elements 29-32, OR elements 33 and 34.

The actuator 44 includes a current regulator 8, a power amplifier 9, an electric motor 10, a working mechanism 11, a current sensor 36.

As an electric motor 10, a direct current electric motor can be used.

A tachogenerator can be used as a speed sensor.

The third source 16 of the constant signal forms at its output a signal proportional to the magnitude of the predetermined acceleration of the electric drive 44, and the fourth source 35 of the constant signal is designed to form a dead zone when forming a relay control law by position in the driver 3 of the control signal} 1i.

For definiteness, we consider the operation of the system in the digital execution of the setting device 1, the comparison unit 2, the position sensor 12, and the matching converter 14.

The system works as follows.

From the output of the setting device 1, the value of the specified movement in the parallel code enters the first input of the comparison unit 2, the second input of which receives the parallel code from the output of the sensor 12-. south, corresponding to the value of the displacement. The output signals of the comparator unit 2 are the error module code and the error sign signal (logical one with a positive error and a logical zero with a negative error.

Analog signals corresponding to the mismatch code in the position, the given acceleration code and the speed code are fed to the inputs 45-47, respectively, of the positioning search start unit 15. In accordance with the information received, the positioning start search unit 15 generates signals that are corrected by a logical form factor. 3 control signals, which ensure the formation of positional diagrams of the electric drive 44 in accordance with the specified acceleration value.

The principle of the predicative model is based on the operation of search unit 15 on the 4a; ia positioning. In block 15, the search for the start of positioning on a real-time basis is repeatedly analyzed to see if the speed can simultaneously reach zero values and the position difference from the current values with a deceleration equal to the specified acceleration value a. Depending on the results of the analysis, a control signal is generated that causes the key 5 (or 7) to close and feed a positive (or negative) constant signal to the input of the electric drive 44, i.e., the relay controls the electric drive 44.

The analysis is carried out by comparing the roots of the velocity and positional equations of motion of the electric drive 44, solved with respect to time and recorded in real time.

V "V ..- m, 5 a3dt; (one)

about

 - m / f (Un - TD aadt) dt; (2) ° A5k 0;

.

VH schd asdt; (3) tj

Asl m (,) 5 a3dt) dt, (4)

where Un, A5n are the current values of velocity and position mismatch, with respect to which the analysis is carried out;

AQ, D5k — final speed and position mismatch values, assumed to be zero; az is the specified acceleration value; t / is the scale factor of time.

The introduction of the time scaling factor makes it possible to solve the equations with hardware at an accelerated rate, which in turn, depending on the ratio of the roots (more or less), predicts further movement of the electric drive 44 and forms operational control to achieve the control goal.

After the system is started up, an analog signal proportional to the magnitude of the specified acceleration, which is integrated in the integrator 17, arrives at the input 45 of the search for start of positioning. The integrated signal is compared in the comparator 18 with an analog signal proportional to the current speed value.

At the output of the adder 19 is formed

.

the signal UI asdi, which is subsequently integrated into the integrator 20. The integrated signal in the comparator 21 is compared with the current value of the position error. The moment of switching of the comparator 18 corresponds to the fulfillment of condition 3, and the moment of switching of the compressor 21 is of condition 4.

If the comparator 18 is triggered earlier than the comparator 21, then the root of the velocity equation is less than the positional root and, therefore, when moving with a given acceleration by the moment the value of the velocity equals zero, the value of the position error is not zero. If earlier the comparator 21 is triggered, then by the time the zero value of the position error is reached, the speed does not reach the zero value.

In accordance with this, to achieve the goal of the equation — simultaneous achievement of a zero velocity value and a position mismatch,

relay control of the electric drive. When the comparator 18 is triggered earlier, the signal of the logical unit from its output goes to the inputs of the elements OR 24 and 27, but passes only through the channel formed by the elements OR 24 and AND 25 on

0 The R input of the RS flip-flop 26, which generates at the inverse output a signal that triggers the key 5 and sends a constant positive signal to the input of the electric drive 44.

5 When the comparator 21 is triggered earlier or when the comparators 18 and 21 are simultaneously triggered, the R-input of the RS flip-flop 26 receives a logical zero signal and it generates a signal at the non-inverse output causing the switch 7 to be triggered and a constant negative signal applied to the electric drive 44 .

After triggering the comparator 18 or the comparator 21 at the outputs of the element OR 22

 and the one-shot 23, a pulse is generated, which simultaneously resets the integrators 17 and 20. The single-shot 23 expands the reset pulse to the value needed to completely reset the integrators 17 and 20. After the integrators are reset, 17 and 20

0, the operation cycle of the position start search block 15 is repeated. The frequency of repetition of work cycles is determined by a time scaling factor.

The operation of the control signal generator 3 is carried out in such a way that

5, the key control signal 5 appears in the following ratio of signals at its inputs.

Р, МДзн5к + МАЗ „5к

where M is the logical “1” signal at the inverse of Q output of the trigger 26;

M - logical “1 on forward” signal

trigger output 26; LZN - signal mismatch sign

position;

S is the logical signal of equality of consistency on the position of the dead zone size; SH -logical SH -logical "O. The key control signal 7 appears in the following ratio of signals at the 0 inputs of the mode selector

P2 MLS5n - - MAZIzn.

When the error module attains the position of the dead zone value, the SH signal from the output of the fourth constant signal source 35 blocks the operation of the control signal generator 3 and the electric drive 44 stops.

Thus, the proposed POSITIONE1 electric drive control system differs from the known systems by simple reconfiguration when the moment of inertia or static moment changes, since for reconfiguration it is only necessary to change the voltage setting at the output of the specified acceleration setpoint unit, which allows to obtain a process that is optimal in speed.

Claims (3)

1. A positional control system for an electric drive containing a setter connected by an output to the first input of a comparator unit connected by sign and modular outputs to the first and second inputs of a control signal generator connected to the first and second outputs from the control inputs of the first and second keys, respectively, connected by information inputs to the outputs of the first and second sources of a constant signal, respectively, and outputs to the first and second inputs of the electric drive, the inputs of which are set A speed sensor and a position sensor connected by the output to the second input of the comparison unit, characterized in that, in order to improve the accuracy of the system, it additionally has a positioning start search unit, a third and fourth constant signal sources and a matching converter connected by the input to the modular the output of the comparison unit, and the output to the first input of the search unit of the beginning of positioning, connected by the second input to the output of the third source of the sustained signal, the third output to the output of the speed sensor and the first and second outputs to the third and fourth inputs of the control signal generator connected by the fifth input to the output of the fourth constant signal source. 2. The system according to claim 1, wherein the search for the start of positioning comprises a first integrator connected by an output to the first input of the adder and to the information input of the first comparator connected by the output to the forward input of the first element AND, to the inverse input of the first element OR and to the first input of the second OR element, connected by the output to the one-vibrator input, connected to the reset input of the first integrator and to the reset input of the second integrator, connected by an information input to the output of the adder, and the output from ormatsionnym input of the second comparator output connected to a second input of the second OR gate, to the inverse input of the first AND gate, to the input of the first forward; the OR element and to the first input of the second element AND, connected by the second input to the output of the first element OR, and the output to the R input of the RS trigger, connected by the S input to the output the first element And, with the first, second and third inputs of the block are respectively the reference input of the second comparator, the information input of the first integrator and interconnected reference the input of the first comparator and the second input of the adder, and the first and second outputs of the block are the inverse and direct outputs of the RS flip-flop. 3. The system according to claim 1, characterized in that the control signal generating unit contains an element of equivalence connected to the output with inverse inputs of the first and second elements And and with the first inverse inputs of the third and fourth elements And, the outputs of the first and third elements And connected with the first and with the second inputs of the first element OR, and the outputs of the fourth and second elements AND are connected to the first and second inputs of the second element OR, the first direct inputs of the first and second elements AND and the second inverse inputs The third and fourth elements And are interconnected and form the first input of the generator, the first input of the element of equivalence is the second input of the generator, the second direct input of the second element And and the direct input of the third element And are interconnected and form the third input of the generator, the second direct the input of the first element And and the direct input of the fourth element And are interconnected and form the fourth input of the former; the second input of the element of equivalence is the fifth input of the former. 6 2C B hell 2S Fy