SU330262A1 - ELECTRO-HYDRAULIC DIGITAL FOLLOWING SYSTEM - Google Patents

Description

The invention relates to the field of machine tools and can be used, for example, in contour software control systems.

Electro-hydraulic relay impulse tracking systems are known, in which in each of the positive and negative error signals the volumetric dosing devices are connected to the working cavities of one of the spools of each spool relay unit with electromagnetic control, and in the error signal conversion unit, the outputs of the reversing binary counter are connected to the input of the reverse binary counter. the logical element "OR, whose input is connected to the valve to open one of the inputs of the ferrotransistor modules, The outputs of which are connected to the corresponding inputs of the control units.

A disadvantage of the known pulse relay tracking system is the low quality of regulation.

The proposed electrohydraulic digital tracking system is different in that in order to improve the quality of control, the output of each of the n reversible binary counter triggers is connected to the corresponding valve of the ferrotransistor modules, the output of each of which is connected to the corresponding electromagnets relay relay blocks connected to volumetric dosing units. The outputs of the relay spool blocks are connected to the working cavities of the actuating cylinder.

FIG. 1 shows a general structural block diagram of the proposed system, where 1 is a program block; 2 - control pulse synchronizer; 3 - unit of digital conversion of the positive direction signal; 4 is a digital signal conversion unit of the negative direction; 5 - switching control unit, 6 and 7 - switching electromagnet control units of relay spools, 8 - electro-hydraulic digital regulator; 9 - initial state sensor; 10 is a feedback system; 11 - synchronize; or feedback pulses; 12-clock generator; 13 - reversible counter; 14 - the executive cylinder; AI and A - pulse synchronization frequency; B - clock frequency; ai6i, "262, ..., I fli6b AChba, ..., as68 J - input channels;

EM, EM2, ..., EL “16 1

„,. ., „1 о« 1- electromagnets.

EM I, JM 2, -, E. EI 16 I

FIG. 2 shows a diagram of an electro-hydraulic digital controller, where: 15-22 are volumetric dosing units; 23-30 - relay blocks

spools; 31 - relay directional spool; 32 - pressure from the pump; 33 - drain; 34 — working cavities used by the ity cylinder.

FIG. 3 shows the reversing circuit of the counter and the circuit of the digital signal conversion unit, where: BI, Bp, Siy are the valves open; B +, Vventili; ФГь ФТ-, ФТ -. ,,

FT - ferrotransistor modules: 55-triggers.

FIG. Figure 4 shows a sequence diagram of the operation-ferrotransistors of digital conversion units for signals of a positive or negative direction and a picture of the displacement of volumetric dosing systems.

The pulses of the program of the program block / synchronization clock with the pulse synchronization frequency / li from the generator 12 clock pulses are fed to one of the inputs (depending on the specified direction) of the reversible counter 13. In addition, feedback pulses are received at the input of the reversing counter 13 after synchronization pulse synchronization frequency .4i from the generator 12 clock pulses. Thus, the number of emulsions contained in a reversible counter and is a system error in a pulsed form.

The error signal, depending on the sign, is input to the digital conversion section 3 of the positive direction signal, or to the 4 digital conversion section of the negative direction signal. In addition, a clock frequency b from a generator of 12 clock pulses is applied to the inputs of blocks 5 and 4.

If the system error (in accordance with the state of the reversing counter) does not exceed + 2 °, then the clock frequency B pulses in a certain sequence arrive at the input channels a, 6i 02, 63 control units 6 and 7, turning on the electromagnets of the relay spools, electro-digital controller eight.

At a system error of +2, the clock pulses of frequency B fall in a certain sequence on the input channels az, bz, OA, b of control blocks (s and 7.

If the system error is equal to +2, then the pulses of the clock frequency B in a certain sequence are fed to the inputs az, o, b, b of the control units 6 and 7 by switching on the electromagnetic relay spools.

Finally, in the case of an increase in the error to +2, the pulses of the clock frequency B in a certain sequence are fed to the input channels a /, b, as, 6s.

If the error is equal to a certain binary combination, then the pulses of the clock frequency B are fed to the inputs of the corresponding combination of control units for switching on the electromagnets of the relay spools associated with the bits of the reversible counter 13.

of the spools, and in the case of a polishing field, a group of control units is connected by turning on the electromagnets of the relay spools. Work of various combinations of blocks 6

or 7 is connected with the need to regulate the speed of the actuating cylinder depending on the error signal, i.e. depending on the state of the reversing counter 13. Electrohydraulic digital

The regulator 8 (see FIG. 2) is a combination of relay spool blocks 23-30 with electromagnetic control, switched in forced mode for driving volumetric metering units 15-22. Each spool is controlled by two corresponding electromagnets EMB ..., 9Mie or 3MS, 7 EMF of the control units for switching on the electromagnets of relay spools (respectively 6 or 7). For example, when a pulse 6 is received at input i of block 6, a high forcing voltage is applied to the 3Mi electromagnet of the corresponding relay spool, after which the spool is instantly transferred to another extreme position, and the voltage on the EM electromagnet decreases to the support level. Further, when a pulse arrives at the input b of the control unit by turning on the electromagnets of the relay spools, the voltage from the electromagnets 3Mi is removed,

and a high forcing voltage is applied to the BMz electromagnets of the same spool, after which the spool instantly returns to its original position, and the voltage on the EM2 electromagnet decreases to

support

All spools of the electrohydraulic digital regulator 5 are connected with the corresponding control units for switching on the electromagnets of the relay spools and operate

similarly. The forced switching of the spools makes it possible to realize a practically inertialess communication of the electronic control circuit of the actuator.

It was noted above that the blocks of relay spools of 23-30-30 electro-hydraulic digital regulator 8 control volumetric metering units 15-22, which directly implement digital control of the speed of the hydraulic actuating cylinder 14.

The control cylinder 5 is reversed using the switching control unit 5 (Fig. 1). So, if the system error is positive, then the clock frequency B pulses go to the input a of block 5, it works

(with force) electromagnet ZUI relay spool direction 31, the pressure from the pump 32 is supplied to the right cavity of the executive cylinder (see Fig. 1), and the digital speed control is carried out by an electro-hydraulic digital regulator 8 on the drain from the left cavity of the executive cylinder.

The EM electromagnet of the relay spool of direction 31 is pumped (with force), pressure from pump 32 is supplied to the left cavity of the executive cylinder, and digital speed control is performed by an electro-hydraulic digital regulator 8 at the drain from the right cavity of the hydraulic cylinder.

The initial state sensor is designed to set the reversible counter 13 to the zero state, to reset the ferrotransistors of blocks 3, 4, digitally convert the signals of the positive and negative directions, to transfer all spools of the electro-hydraulic digital controller S to the initial position.

The electrohydraulic digital regulator 8, the basis of which the circuit is a complex of blocks of relay spools 23-30 with electromagnetic control and volumetric metering units 15-22 with hydraulic control, contains four positive direction cells, which are a combination of volume metering units 19-22 with the corresponding blocks of relay spools 27-30, and four negative-direction cells, which are a combination of volumetric metering devices 15-18, with corresponding blocks of relay spools 23-26, one relay slide valve 31. The relay directional spool connects the Yao pressure from the pump 32 to one or another cavity of the executive cylinder, the electro-hydraulic digital controller provides digital control of the speed of the executive cylinder on the drain.

Consider the operation of one positive direction cell, for example, a volumetric metering device 15 with a relay spool block 23. The relay spool blocks are a combination of two two-position two-edge spools switched by pushing electromagnets from one extreme position to another. In the normal upper position, all the working slots of the relay spools 23 are closed, and the cavities of the corresponding volume dispenser 5 are locked. The total stroke of each zolotyika is about 1 mm, and with each flip of the valve the condition of the slits changes to the opposite. Half of the total stroke of the spool occurs at the opening of the working slots, half - overlap. Thus, the opening and closing of the working slots is in the order of 0.5 mm. Suppose that the electromagnet of the electromagnetic relay of direction 31 is turned on, the pressure from the pump 32 is supplied to the right cavity of the executive cylinder. If the spools in the relay spool blocks 23-26 or dispensers 19-22 are in the normal position (top), then the left cavity of the hydraulic cylinder is locked and its movement is impossible. Let us now assume that at some instant of time the EM электромагнит electromagnet turned on (and the EM4 electromagnet turned off) and the relay valve connected with it instantly shifted down. The left cavity of the executive cylinder turned out to be connected to the upper, lower cavity of the corresponding volumetric watch, and the lower cavity of the dispenser was connected to the drain 33. As a result, the piston of the actuating cylinder 14 moved to the amount corresponding to the dose volume of this dispenser, and the plunger of the dispenser occupied the lower position. Suppose further that at the next moment of time {after one period of the clock frequency B) the electromagnets EM and EM turned on (and EM2 and 3Mz turned off). The left cavity of the hydraulic cylinder was connected to the lower cavity of the same volumetric dispenser, and the upper cavity of the dispenser was connected to a drain. As a result, the hydraulic cylinder piston was able to take the next step, the value of which corresponds to the volume of the dispenser dose, and the dispenser plunger is in the upper position. If further with each new clock pulse B, the spools of the relay spool block will occupy new and opposite positions, the dosing will be almost continuous, and the speed of the actuating cylinder will be determined by the dose and clock frequency B. Moreover, both the forward and reverse plunger strokes dispensers are workers.

From the diagram in FIG. 2 that the four positive direction cells 19, 27, 20, 28, 21, 29 and 22, 30 are connected in parallel to one cavity of the executive cylinder, and the four negative direction cells are connected in parallel to the other cavity of the executive cylinder. Individual cells are distinguished by useful dispenser volumes, which are related to each other as bits of a binary number system. Therefore, when the volumetric metering device 20 is operating, the speed of the executive cylinder will be twice as high, when the volumetric metering unit 21 is four times higher, and when the volumetric metering unit 22 is eight times higher than when the volumetric metering unit 19. The individual cells can work both separately and and together in any combination.

If the positive direction cell group is in operation, all the spools of the negative direction relay blocks are in the normal state (electromagnet ELG, EM, EMB, 5M8, 5M, o, ZMChg, EMi, EMCh are included) - The work of the negative direction cells is quite similar, however the EM electromagnet of the direction spool relay must be turned on and pressure from the pump 32 is supplied to the left cavity of the executive cylinder 14.

The initial state of the reversible counter (Fig. 3) corresponds to memorization of the number 16 (in this state, the counter is shown in Fig. 3). If a number equal to or greater than 16 is contained in the reversible counter, valve B of the output of the clock frequency pulse B is open to block 3 of the digital signal conversion of the positive direction and the input

channel a of control switching unit 5. If any number less than 16 is contained in the reversible counter, then the output pulse of the clock frequency B is opened to the digital conversion unit 4 of the negative signal and the input channel b of the switching control unit. As noted, when clock pulses B hit the input channel a of block 5, the electro-hydraulic digital controller 8 is connected to the executive cylinder in such a way that movement is possible only in the positive direction. Accordingly, when clock pulses B hit input b, movement of the executive cylinder is possible only in the negative direction.

The digital conversion unit of the signal of a negative or positive direction is a combination of gates and ferrotransistor modules, the nature of which is due to the state of the reversible counter. Let, for example, the state of the counter 10001, i.e., the positive increment relative to the initial state be one pulse. The gate valve BI will then open and the operation of the ferrotransistor OB associated with this gate will follow the cyclogram in FIG. 4. Sequential appearance of pulses in channels ai, b, “2. Bz will give a clear definiteness in the triggering of electromagnets EM, EM2, 9Mz, EM, and the theoretical picture of the movement of the dispenser will look like the last graph of the cyclogram in FIG. 4. In fact, with the correct choice of the clock frequency B, the dosing will be almost continuous. At the same time, the speed of movement of the hydraulic cylinder is minimal (in accordance with the increment of the reversible counter), since the useful volume of the metering device is the smallest.

If the increment of the reversible counter increases to two pulses (state 10010), then of the valve group B-B iv, only the valve B c will remain open. The ferrotransistors associated with this valve will operate according to a sequence diagram, similar to FIG. 4. The dosing of the working fluid at the discharge from the hydraulic cylinder is carried out by the dispenser 20 and the speed is twice the minimum.

It is not difficult to show further that the speed of the hydraulic cylinder will exceed the minimum as many times as the increment of the reversible counter relative to its initial state.

From the structure of the digital conversion unit, it can be seen that the output of the pulses into the channels a-, is related to the state of the valves B, B} -5 | y,

i.e. with a reversible counter state. In channels b, -; 1, the pulses arrive with a delay of one clock cycle regardless of the state of the reversible counter. This is done so that the spools of the relay blocks can return to normal when the counter increment changes in the intervals between clock cycles B.

PRIORITY 3 of the thru and

Electrohydraulic digital tracking system containing program block, control pulse synchronizer, generator

clock pulses, reversible counter, negative direction digital signal conversion unit, performed on ferrotransistor modules, positive direction digital signal conversion unit, executed on ferrotransistor modules, switching control unit, electrical switching modules of relay spools, electro-digital regulator, made in the form

connecting relay spool units with volumetric metering devices, an initial state sensor and a feedback system, characterized in that, in order to improve the quality of regulation, the output of each of the n triggers

the reversible counter is connected to the corresponding valve of the opening of the ferrotransistor modules, the output of each of which is connected to the inputs of the corresponding electromagnets through the appropriate control unit,

associated with the corresponding blocks of the relay spools connected to the volumetric metering units, the outputs of the blocks of the relay spools being connected to the working cavities of the actuating cylinder.

Vuz.2