SU1730610A1 - Digital tracking system - Google Patents

Abstract

The invention relates to digital tracking systems with contactless DC motors and can be used in manipulation work and other automation devices as an executive tracking system. The purpose of the invention is to simplify the system and increase its speed. The digital following system includes the error meter 1, the black 2 module formation, the first 3 and second 4 threshold elements, the digital pulse-width converter 5, the reverse relay 6, the switch 7, the non-contact DC motor 8, the gearbox 9, the sensor 10 rotor positions, first 11 and second 12 multipliers, adder 13 and code-frequency converter 14. The invention may find the greatest application in manipulative robots, where when changing the loading moment over a wide range, high speed is required and overshoot is unacceptable. 2 Il. WITH

Description

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The invention relates to digital servo systems with contactless DC motors and can be used in manipulation robots and other automation devices as an executive tracking system.

The purpose of the invention is to simplify the system and increase its speed.

FIG. 1 is a block diagram of a digital tracking system; in fig. 2 is a block diagram of a digital pulse-width converter for a three-phase non-contact DC motor,

The digital following system (Fig. 1) includes the error meter 1, the module forming unit 2, the first 3 and second 4 threshold elements, the digital pulse-width converter 5, the reverse relay 6, the switch 7, the non-contact DC motor 8, gearbox 9, rotor position sensor 10, first 11 and second 12 multipliers, adder 13 and code-frequency converter 14.

A digital pulse-width converter (Fig. 2) includes an address generation unit 15, an address conversion unit 16, read only memory 17, a first 18, a second 19 and a third 20 pulse-width modulators, a generator 21.

The following abbreviations and notation are accepted in the text:

CShIP - digital pulse-width converter;

БДПТ - contactless DC motor;

PCH - code-frequency converter;

DPR - rotor position sensor;

BFA - address generation unit;

BPA - address translation block;

ROM - read only memory;

PWM - pulse width modulator;

BFM - module forming unit; &, v0, v, D # | ,, D0 is the input, output angles, the error of the tracking system and their digital codes, respectively;

I D $ I - system error code module;

FAL is the triggering code of the threshold elements;

sign D $ is the sign bit of the system mismatch (error) code;

sign W - sign of the direction of rotation of the electric motor;

gsh is the pulse frequency at the output of the code-frequency pulse converter;

Mn - the moment of load on the engine shaft;

Mo is the maximum synchronizing torque of the engine;

Fr, Fs is the magnetic flux of the rotor and stator of the electric motor, respectively; tn is the instant of system switching from continuous to discrete-step mode.

CSRT 5 is designed to convert the angle of rotation of the rotor in the system

0 three latitude modulated sequences. The modulation depth of the indicated sequences is determined by the digital code Uo. in this case, in the continuous mode, U0 remains constant, and in the discrete-step mode, it changes according to the transformation law of the PKC 14.

CSRT 5 contains serially connected BFA 15, BPA 16 and ROM 17, in which the pulse width codes are written

0 three functions (for example, harmonic), shifted by 120 °. These codes are fed to the inputs of three PWM 18, 19, and 20, where they are converted into pulse-width sequences. To the control inputs of the task

5 modulation depth PWM connected to the output of the generator 21. The outputs of the PWM 18, 19 and 20 are connected to the relay 6 of the reverse, which is controlled by the signal sign, and when the sign of the latter changes, the signs sign

0 1, sign 2, sign 3 PWM 1, PWM 2, PWM 3 signals, i.e. the direction of the currents in the windings BDPT 8, switched switch 7.

The system uses incremental rotor position sensor

5 is a sensor based on photo reading sensing elements, the counting of pulses from which makes it possible to obtain a digital code D $ 0 to close the main feedback to the error meter 1. In addition, when using the incremental sensor, it is possible to obtain the direction of rotation sign w.

In static mode, Df D00 and D (9 0, the first threshold element 3 has

5 is the maximum output code, and the second threshold element 4 is the zero signal at the output. As a result, the output of the DPR 10 by means of multiplier 12 is disconnected from the input of the PSRT 5, and the output of the RCF 14 is connected to its input. Since 0 D 0, the pulses at the output of the RCF 14 are absent, and PWM 18, 19 and 20 generate pulses whose duration is constant in time. The stator field BDPT 8 is fixed, maximum in magnitude, and the angle po5 of its gate relative to the rotor is equal to

Mn -r a - arcsin -rr-. Thus, in mode

Mq

the rest of the TIRB 8 develops a synchronizing moment, fully compensating

the moment of load on the engine shaft with zero mismatch, i.e. the system has astatism with respect to momentary disturbances.

When a large hopping signal is applied to the system input, the code of the error signal module exceeds the triggering code of the threshold elements, i.e. I AUn, the threshold elements 3 and 4 are triggered, as a result of which the output of multiplier 11 is zeroed out, and the output of PKC 14 is disconnected from the input of the chipset 5. The activation of threshold element 4 causes the multiplier 12 and the adder 13 to trigger this input the pulse output of the DPR 10 is connected. At the same time, by the signal AUn, the BNP 16 transforms the output code of the BFA 15 thus, between the magnetic fluxes of the stator FS and the rotor Fr BDPT 8 will amount to 90 el. hail. The error signal code A (9 arrives at the input of the CSRT 5, the output of which through the reverse 6 relay is connected to the input of the switch 7. The stator field of the engine, due to the rigid connection in the angular position with the rotor, through the DPR 10 rotates synchronously with the rotor, its angle with the latter is 90 el.rad., And its module has a maximum value, Therefore, the motor, rotating as a contactless DC motor with a relay regulator, fulfills the mismatch. Moreover, the maximum supply voltage on the windings of the electric motor ensures minimum time for working out this mismatch.

With a decrease in the error signal at some time point t tn, determined by the magnitude of the trigger code, the threshold elements 3 and 4 are triggered. This causes the output of the second threshold element 4 to be zeroed and, due to the action of the multiplier 12, the relationship between the DPR 10 and the MSBR 5. is broken. At the same time, a high level signal appears at the output of the first threshold element 3. This leads to the fact that the input of the chipset 5, through the adder 13 and multiplier 11, goes to the FSC 14 output. In addition, the control unit 16 transforms the code from the output of the BFA 15 so that the magnetic field of the rotor and stator of the electric machine are combined . The sign signal together serves to select the correct reference direction.

These switches lead to the fact that starting from the moment of time t tn, the motor and the system as a whole start working as discrete-step ones. This mode is characterized by the fact that the magnetic field

The stator windings of the TIRB 8 move discretely in space one step with the arrival of each new impulse from FCP 14. In this case, the sign of the moment on the motor shaft is determined by the mutual orientation of the magnetic fluxes of the rotor Фр and the stator FS. At the moment of switching t tn, the magnetic fluxes of the rotor and stator of the electric motor coincide, but already at the next

the moment of time at t tn + 1 the rotor will overtake the stator flow and the motor develops a decelerating moment, and the moment pulses with the arrival of each pulse from PKCh 14 to the input chipboard 5. With a decrease in the rotor kinetic energy, it will begin to lag behind the flow of the stator , reducing the mismatch in the system to zero.

Thus, at large mismatches x (t tn - 1), the TIRBT 8 is controlled by a relay controller, which, as is well known, provides the maximum speed.

At the moment of switching t tn, the magnetic fluxes of the stator and the rotor are combined, which also leads to an increase in the system speed. Indeed, in the prototype system after translating the TIRB 8 into

step mode (with the FS module increased to the maximum), i.e. after the moment of time t tn, some more time until the combination of FS and Fr is applied to the rotor, an accelerating moment acts

leads to the need to extinguish it in subsequent periods of time, and therefore, to increase the time of the transition process of the system in discrete-step mode,

Immediately after switching to the stepping mode, the engine develops a braking moment, and consequently, the transient process of the system in the discrete-continuous mode is significantly less.

Claims (1)

Invention Formula A digital tracking system containing the first and second multipliers connected by the first inputs to the outputs of the first and second threshold elements, respectively, and the outputs to the first and second inputs of an adder connected to the information input of a digital pulse-width converter, the output of which is connected to the information input a reverse relay, the output of which is connected via a series-connected switch and non-contact motor 1 of direct current to the input of the reducer, the output of which is the output of the SI and the input of the rotor position sensor, the pulse output of which is connected to the second input of the second multiplier, and the digital output to the difference input of the error meter, the summing input of which is the system input and the output connected to the sign input of the reverse relay, to the input of the code converter the frequency connected by the output to the second input of the second multiplier and to the input of the module forming unit whose output is connected to the inputs of the first and second threshold elements, which, in order to simplify and increase ystrodeystvi, therein digital pulse-pulsed converter comprises a block forming the address conversion unit addresses, a read only memory, a generator, and three pulse-width modulator outputs FIG. 2 which are the output of a digital pulse width converter, the inputs of the modulation depth are connected to the output of the generator, and the information inputs are connected to the outputs of a permanent storage device whose address inputs are connected to the output of the address conversion block, the control input of which is control input of the digital pulse-width converter, connected to the output of the first threshold element, the sign input, which is the sign input of the digital pulse-width converter, according to favoring the rotor position sensor output and data input - output from the address generating unit whose input is a digital information input pulse width converter.