RU2132080C1 - Digital electrohydraulic tracing control system for position of object - Google Patents

Abstract

FIELD: engineering, in particular, controlling position of combustion chambers of missile propelling engines, or position of aircraft control surfaces. SUBSTANCE: device has two-level relay control of position of control valve of hydraulic distributor, which provides precision of positioning within range of one lowermost digit of digital position detector. EFFECT: increased precision of positioning, decreased power consumption, decreased weight of power supply source, decreased weight of cable network and weight of complete system. 1 dwg

Description

 The invention relates to mechanical engineering and can be used to control the position of various objects, for example, to control the position of the combustion chambers of liquid rocket engines (LRE) or the steering surfaces of aircraft.

 Known digital tracking control system - an analogue designed to control the operation mode of the engine of the second stage of the LV "Energy" [1]. This device contains a command signal shaper - a digital computer (digital computer) operating in a parallel binary seven-digit code and connected to a stand-alone computing device connected through an amplifying-converting device with a drive electric motor and a discrete feedback sensor connected to the output shaft of the gearbox, which is attached to the control object, while the input shaft of the gearbox is connected to the shaft of the drive motor.

 The system operates by comparing the control codes generated by the digital computer and the position codes of the output shaft of the drive coming from a discrete feedback sensor, while the drive shaft stops when these codes coincide. In this system, the functions of the device for comparing and controlling the electric motor are performed by an autonomous computing device (AVU) working with its own quantization clock, independently with respect to the command signal shaper (digital computer). The disadvantage of such a system is the limited ability to work on a positional load, in which self-oscillations are observed in the system with casting of the output shaft beyond the level determined by the discrete nature of the command.

 There is also known a system - the closest analogue (prototype) described in [2,3], which contains a command code generator (CVM), a power hydraulic cylinder having a piston with a rod that is attached to the control object and to the feedback lever, a control valve with a control valve connected to the feedback lever, while the hydraulic distributor cavities are connected to the cavities of the power hydraulic cylinder and to the discharge and discharge lines of the working fluid, the control digital electro-hydraulic drive (UTSEGP), which has several times yadnyh electrohydraulic amplifiers connected to the command signal shaper (DCM) and bit adder chain pistons extreme output shaft of which is connected to the feedback lever.

 The system is as follows. The digital computer sends a command in the form of a binary parallel code to the windings of several discharge electro-hydraulic amplifiers of the UTsEGP, as a result of which the corresponding discharge pistons of the summing chain and the rod of the extreme piston of the UTsEGP move apart the feedback lever, and with it the control valve of the hydraulic distributor. The movement of the valve spool causes the piston of the power cylinder, and with it the control object, to move the feedback lever, which moves the control valve to the side of closing the throttle valve windows. When the flow of working fluid from the control valve to the power hydraulic cylinder stops, the movement of the piston of the power hydraulic cylinder, and with it the control object, also stops.

 However, during the operation of this system, significant intermittent movements of the control spool forward and backward relative to a given position occur, especially when changing the least significant bits to one senior, which are transmitted to the piston of the power hydraulic cylinder, and through it to the control object. In addition, UDEGP has significant dimensions and mass, and consumes several times more electricity than analog drives, which requires an additional mass of batteries put into orbit.

 The technical result of the present invention is to reduce the cost of electricity for controlling the drive, and, as a result, reducing the mass of the onboard power supply, the mass of the cable network, as well as reducing the mass of the system as a whole.

 The technical result is achieved by the fact that in the well-known digital electro-hydraulic servo control system containing a command code generator, a control valve with a control valve, the cavity of the control valve is connected to the discharge and discharge lines of the working fluid and to the cavities of the power hydraulic cylinder having a piston with a rod that is attached to to the control object and to one of the ends of the feedback lever, an additional hydraulic cylinder is introduced, the cavities of which are connected to the cavities of the electrog hydraulic amplifier and with the discharge and discharge lines of the working fluid, while the piston rod of the additional hydraulic cylinder is connected to one of the ends of the feedback lever and is connected via a gearbox to a digital position sensor connected via an amplifier-code converter to the summing device, which is connected to the command code generator and with a matching device connected to a selector connected to a reference voltage unit and to a command signal amplifier connected to an electro-hydraulic amplifier Tieliu, the feedback lever via rods connected to one end of an additional arm, the other end of the further arm connected to the housing of the power cylinder, wherein the additional lever connected to the control spool of the control valve.

 Thus, thanks to this technical solution, the power part of the digital system is controlled using one analog electro-hydraulic amplifier, which reduces energy costs, the mass of the on-board energy source, the mass of the cable network and the mass of the whole system.

 The implementation of the claimed technical solution is illustrated using a block diagram of a digital electro-hydraulic system shown in FIG. 1 and the dependence of the command voltage on the difference code shown in FIG. 2.

On the block diagram (Fig. 1), the numbers indicate
1- shaper command code (FKK);
2 - summation device (CSS);
3 - amplifier code converter (CCP);
4 - matching device (SU);
5 - selector (C):
6 - reference voltage block (BON);
7 - command signal amplifier (UKS);
8 - electro-hydraulic amplifier (EHU);
9 - an additional hydraulic cylinder;
10 - feedback lever;
11 - thrust;
12 - additional lever;
13 - a hydrodistributor;
14 - power hydraulic cylinder;
15 - control object;
16 - gearbox (P);
17 - digital position sensor (DAC);
18 - line pumping the working fluid;
19 - line draining the working fluid.

 FKK 1 with its output is connected to one of the inputs of DC 2, while the output of SU 2 is connected to the input of SU 4, the output of which is connected to one of the inputs C 5, while the other input C 5 is connected to the BON 6. Output C 5 is connected to the input of UKS 7. The output of UKS 7 is connected to the input of the EGU 8, the cavities of which are connected to the discharge lines 18 and discharge 19 of the working fluid and to the cavities of the additional hydraulic cylinder 9. The piston rod of the additional hydraulic cylinder 9 is connected to the feedback lever 10 and to the gearbox 16. Gear 16 connected to the DAC 17, the output of which is connected to the input of the CPC 3. Output Y PC 3 is connected to the second input of the CSS. The feedback lever 10 is connected to the piston rod of the power hydraulic cylinder 14, while the piston rod of the power hydraulic cylinder is connected to the control object 15. The control valve of the hydraulic valve 13 is connected to an additional lever 12, while the cavity of the hydraulic valve is connected to the cavities of the hydraulic cylinder 14 and to the discharge pipes 18 and discharge of 19 working fluid. One end of the additional lever 12 is connected to the housing of the power cylinder 14, and the other end is connected to the rod 11, which is connected to the feedback lever 10.

 An on-board computer can be used as a command code shaper (FCC), and a summing device (CSS) can be made on the basis of well-known half-adder microchips or full adders [4]. The matching device (CS) can be performed on the basis of well-known microcircuits of arithmetic-logic elements, while the comparison functions can be achieved through the use of well-known circuits that implement the functions of equalities, strict and non-strict inequalities [5]. The selector (C) can be made on the basis of an eight-channel multiplexer [4], and a bipolar resistor voltage divider can be used as a block of reference voltages (BON). The command signal amplifier (UKS) can be made on the basis of well-known DC amplifier circuits, based on operational amplifiers [6], and the code converter amplifier (CPC) can be made on the basis of the known schemes of the amplifier-limiter and the Gray code-binary converter code "[4].

 Consider the operation of a digital electro-hydraulic tracking system for controlling the position of an object.

где δ_p - код разности; δ $\genfrac{}{}{0ex}{}{\text{*}}{\text{p}}$ - второе пороговое значение кода разности;
U_к - напряжение командного сигнала; U^min _к - напряжение командного сигнала низкого уровня; U^max _k - напряжение командного сигнала высокого уровня.FKK 1 issues the command code δ _k to CSS 2, in which the feedback code δ _oc generated by the CPC 3 is subtracted from the command code. The resulting difference code δ _{p is} sent to CS 4, which implements the comparison function and converts the difference code to the control code δ _y C 5, which, in turn, depending on the incoming code, outputs one of five values of command voltages generated by BON 6 and supplied to analog inputs C 5. The joint work of SU 4, C 5 and BON 6 is to implement the following algorithm:

where δ _p is the difference code; δ $\genfrac{}{}{0ex}{}{\text{*}}{\text{p}}$ - the second threshold value of the difference code;
U _to - voltage command signal; U ^min _k - voltage command signal low level; U ^max _k is the voltage of the command signal of a high level.

 The above algorithm is illustrated using FIG. 2.

The command voltage is supplied to UKS 7, where it is converted to a command current i _k flowing through the windings of an electromechanical converter of a one- or two-stage EGU 8. When a command signal arrives at EGU 8, the hydraulic spool (X _zg ) is displaced, as a result of which the piston begins to move , and with it the rod of the additional hydraulic cylinder 9 (Y ^III _dts ), which causes the shift of the feedback lever 10, rod 11, additional lever 12, and with them the control valve of the control valve 13 (X _zu ), which, in its in turn, causes the movement of the piston, and with it the rod of the power hydraulic cylinder 14 (Y ^III _ss ). Through the reducer 16, the movement of the piston rod of the additional hydraulic cylinder 9 in the form of an angle of rotation (φ _d ) is transmitted to the DAC 17 generating the code δ _{d of the} current position of the piston rod of the additional hydraulic cylinder 9, which, after amplification and conversion to CPC 3 (δ _oc ), enters the DC 2 where is subtracted from the command code δ _k . The movement of the piston and rod of the additional hydraulic cylinder 9 stops when the EGU 8 spool is installed in a position that overlaps the discharge line 18 and the drain 19 of the working fluid in the EGU.

 The movement of the piston rod of the power hydraulic cylinder 14 causes the control object 15 to move and the feedback lever 10 to shift in the opposite direction, while the rod 11, the additional lever 12 and the control valve of the control valve 13 are also shifted in the opposite direction. The movement of the piston and rod of the power hydraulic cylinder 14, and together with them and the control object 15, stops when the control valve spool 13 closes the discharge pipe 18 and the discharge 19 of the working fluid.

A feature of the system is a digital two-level relay control of the position of the control valve of the control valve, which is carried out as follows. If the difference code δ _p modulo equal to or exceeds the second threshold value δ $\genfrac{}{}{0ex}{}{\text{*}}{\text{p}}$ , then in the UKS, and therefore in the EHU, a high level command signal of one or another polarity is received corresponding to the maximum movement of the EHU spool and the maximum opening of its throttle windows, which leads to the maximum speed of the piston of the additional hydraulic cylinder, and with it the control valve of the hydraulic valve . As the piston of the auxiliary hydraulic cylinder moves, the difference code δ _p , due to the feedback action, decreases, and when it modulo becomes less than the second threshold value δ $\genfrac{}{}{0ex}{}{\text{*}}{\text{p}}$ , but is greater than or equal to the unit of the least significant bit of the DAC (the first threshold value), in the UKS, and therefore in the EHU, a low-level command signal is received, which leads to the EHU spool shifting by a certain value towards the neutral position, which corresponds to a certain minimum opening of the EHU throttle windows and leading to a decrease in the speed of the piston of the additional hydraulic cylinder, and with it the control valve of the hydraulic distributor. With a further decrease in the difference code, when it in absolute value becomes less than the unit of the least significant bit of the DAC (the first threshold value), a zero command signal is supplied to the UKS, and therefore to the EHU, as a result of which the EHU spool is set to a neutral position that overlaps the discharge lines and draining the working fluid, which leads to a stop of the piston of the additional hydraulic cylinder, and with it the control valve of the hydraulic distributor. If due to the action of inertial or any other forces, the piston of the additional hydraulic cylinder, and with it the control valve, do not stop, but continue to move, then, depending on the received difference code, command signals are sent to the EHU in accordance with the above algorithm, interfering with the movement and, ultimately, setting the piston of the additional hydraulic cylinder and the control valve of the control valve to a predetermined position within the plus or minus units of the minor discharge of the central heating unit.

The choice of the value of the second threshold value δ $\genfrac{}{}{0ex}{}{\text{*}}{\text{p}}$ is the subject of optimization for a specific technical task, and is determined from the condition of ensuring the retention of the control valve of the control valve in a given position.

 Thus, the claimed system due to the digital two-level relay control of the position of the control valve of the control valve ensures the accuracy of the positioning of the control object within plus or minus the units of the low-order digit of the DAC, and the use of one EGU in the claimed system instead of several, reduces the cost of electricity, mass of the onboard energy source, the masses of the onboard cable network and the masses of the entire system as a whole.

Literature
1. Belitsky D. S., Zharkov M. N., Stoyalov V. V., Shutenko V. I. Electromechanical drive in a control system for liquid rocket engines. News of the Academy of Sciences. Theory and control systems, 1996, N 1, p. 118-124.

 2. Electro-hydraulic servomechanisms with digital control (review) / Issues of rocket technology, N 2, 1965, p. 77.

 3. Baida S. I., Kudryavtsev V. V., Chertok B. E., Shutenko V. I. Digital electro-hydraulic drive in the control system of the launch vehicle "Energy" / Technical cybernetics, M 1, 1990, p. 186.

 4. Handbook of integrated circuits / B. V. Tarabrin, S. V. Yakubovsky, N. A. Barkanov and others, ed. B.V. Tarabrina. -2nd ed. reslave. and add. - M.: Energy, 1981.

 5. Tokheim P. Fundamentals of Digital Electronics: Per. from English -M .: World, 1988.

 6. Aleksenko A. G. et al. Application of precision analog microcircuits / A. G. Aleksenko, E. A. Colombet, G. I. Starodub, 2nd ed. reslave. and add. - M .: Radio and communications, 1985.

Claims (1)

 A digital electro-hydraulic tracking system for controlling the position of the object, comprising a command code generator, a power hydraulic cylinder having a piston with a rod that is attached to the control object and to one of the ends of the feedback lever, a control valve with a control valve, while the hydraulic distributor cavities are connected to the cavities of the power hydraulic cylinder and with the discharge and discharge lines of the working fluid, characterized in that the other end of the feedback lever is connected to the piston rod of an additional g an idro cylinder, while the piston rod of the additional hydraulic cylinder is connected through a gearbox to a digital position sensor connected via a code amplifier to a summing device, which is connected to a command code generator and to a matching device connected to a selector connected to the reference voltage block and to the command amplifier a signal connected to an electro-hydraulic amplifier, the cavities of which are connected to the cavities of the additional hydraulic cylinder and to the discharge and discharge lines eyes liquid, wherein a feedback lever is connected by means of rods with one end of the additional arm and the other end of the further arm connected to the housing of the power cylinder, wherein the additional lever connected to the control spool of the control valve.

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