CN1202360C - Multi-path synchronous hydraulic servo driving device - Google Patents

Abstract

The present invention discloses a multi-path synchronous hydraulic servo driving device which adopts multishaft transmission composed of a plurality of hydraulic servo systems to drive the same load object. In order to ensure that the synchronous transmission adopts a software servo to realize the synchronous transmission of a system, an instruction signal from a computer is output to a power amplifier to operate a servo valve; furthermore, an actuation barrel is operated; a piston is impelled to output displacement, and the pressure of the cavity of the actuation barrel is measured by a pressure sensor, and simultaneously, is output to a signal selector; a pressure average value is selected by the selector, and is compared with a pressure to obtain a pressure difference value which is fed back to a channel by a balance function device; simultaneously, position feedback is combined with the displacement of an output shaft, and is fed back to the power amplifier; thus, a position closed loop system is formed. Each channel pressure is almost the consistent, which relieves the dispeace of pressure among channels and achieves synchronous transmission. Experiments indicate that each channel of the multi-path synchronous hydraulic servo driving device can realize good synchronous transmission; force dispeace caused by the difference value is less than 1.4%.

Description

Multi-channel synchronous hydraulic servo transmission device

Technical field

The present invention relates to a kind of multi-channel synchronous hydraulic transmission, belong to hydraulic transmission and control technique field in the mechanical transmission.

Background technique

Lifting device, lift platform, large hydraulic extrusion press and redundant transmission system etc. are because load is big or because of reliability requirement usually adopts the multichannel driving, both several passages drive a load object simultaneously.Because interchannel difference, interchannel usually can not guarantee Synchronous Transmission, and this kind situation not only can not guarantee transmission performance, can cause the damage of system when serious.The synchronous hydraulic transmission all has application in industry, building, water conservancy, mine and Aero-Space.

Multichannel transmission at present solves stationary problem, and the one, improve machining accuracy, reduce interchannel difference; The 2nd, adopt high-precision fluid distributing valve, promptly the hydraulic oil that comes is equally divided into 3 road or 4 tunnel (can only be used in the very low open loop transmission of precision); The 3rd, in the way of channel output end employing mechanical linkage.These methods can guarantee to a certain extent synchronously, but can not fundamentally guarantee synchronously, when particularly each driving channel is subjected to different interference (differ as signal cause each passage transmission speed different), all the more so, rigid mechanical linkage meeting produces the dispute of power.The hydraulic synchronous system that transmission accuracy is had relatively high expectations must adopt the synchroballistic measure.

Summary of the invention

When the purpose of this invention is to provide a kind of multi channel system and driving same object, how to guarantee multichannel synchronous servo transmission accurately.Cast aside the indemnifying measure of mechanical property, and taked the scheme of " software servo ", successful solution the Synchronous Transmission problem.

A kind of multi-channel synchronous hydraulic servo transmission device of the present invention, it forms the multiaxis transmission by a plurality of Hydrauservo Systems, remove to drive same load object, described hydraulic servo transmission device is made up of power amplifier, servovalve, pressurized strut, detector, coupling cock valve, signal selector, comparator, balance function device, comprehensive output shaft and position feedback, by the next command signal U of computer _iExport to power amplifier, operation servovalve, and then operation pressurized strut promote piston output displacement X _tMeasure pressurized strut cavity pressure P by pressure transducer _i, export to signal selector simultaneously, choose a plurality of passage pressurized strut cavity pressure average P through signal selector _CpAnd compare with one of them passage pressurized strut cavity pressure and to obtain pressure difference value P _e=P _Cp-P _i, feed back to this passage through the balance function device again, simultaneously by position feedback with the Displacement Feedback of comprehensive output shaft to power amplifier, constitute the position closed loop system, make each channel pressure trend consistent, the dispute of alleviation interchannel power reaches Synchronous Transmission.

Described multi-channel synchronous hydraulic servo transmission device adopts a plurality of passage pressurized strut cavity pressure average P _CpCarry out equilibrium and relatively realize balanced control.

Described multi-channel synchronous hydraulic servo transmission device, servodrive adopt " software servo " to reach synchronous drive.

Described multi-channel synchronous hydraulic servo transmission device, whether the automatic sense channel of its detector is stuck, and the thresholding of detector is P _c, when | P _e| 〉=P _cThe time, the coupling cock valve is opened, pressurized strut two chamber UNICOMs.

Described multi-channel synchronous hydraulic servo transmission device, the multivariate decoupling technology has been eliminated the power dispute that causes because of interchannel difference in its signal selector and the balance function device employing modern control theory, and its synchronous difference power is less than 1.4%.

Advantage of the present invention is, removes to drive same load object by the transmission of " software servo " control multiaxis and realizes synchronous drive, and this structural type realizes easily, and is simple in structure.Adopt balanced decoupling zero network to come elimination power dispute promptly thorough again rapidly, solution power dispute problem is guaranteed that the servo-driven conformity of multichannel has obtained breakthrough.

Description of drawings

Fig. 1 is that four-way drives same load object schematic representation simultaneously.

Fig. 2 is multichannel driving structure figure.

Fig. 3 is four-way driving structure figure.

Fig. 4 is that single channel transmits Block Diagram.

Fig. 5 is that four-way transmits Block Diagram.

Fig. 6 is pressure feedback decoupling zero Principles of Network figure.

Fig. 7 is an experimental curve diagram.

Among the figure: 1. power amplifier 2. servovalves 3. pressurized struts 4. detectors 5. coupling cock valves 6. signal selectors 7. comparators 8. balance function devices 9. comprehensive output shaft 10. position feedback

Embodiment

The present invention is described in further detail below in conjunction with accompanying drawing:

The present invention is a kind of multi-channel synchronous hydraulic servo transmission device, comprises computer and driving mechanism, and it removes to drive same load object by power unit, guarantees each power unit Synchronous Transmission control.Described transmission device is made up of power amplifier 1, servovalve 2, pressurized strut 3, detector 4, coupling cock valve 5, signal selector 6, comparator 7, balance function device 8, comprehensive output shaft 9 and position feedback 10, by the next command signal U of computer _iExport to power amplifier 1, operation servovalve 2, and then operation pressurized strut 3 promote piston output displacement X _tMeasure pressurized strut cavity pressure P by pressure transducer _i, export to signal selector 6 simultaneously, choose pressure average P through signal selector 6 _CpAnd compare with one of them passage pressurized strut cavity pressure and to obtain pressure difference value P _e=P _Cp-P _i, feed back to this passage through balance function device 8 again, simultaneously by position feedback 10 with the Displacement Feedback of comprehensive output shaft 9 to power amplifier 1, constitute the position closed loop system, make each channel pressure trend consistent, the dispute of alleviation interchannel power reaches Synchronous Transmission.

Synchronous drive device power unit of the present invention can be pressurized strut, also can be the hydraulic rotating motor.Generally speaking, pressurized strut is used for the short distance transmission, and revolution motor then is used for long apart from transmission, but principle is the same.The present invention is existing to be the process that power unit describes four passage Synchronous Transmission with the pressurized strut.

Shown in Figure 1 is four-way transmission schematic representation, and four pressurized struts promote a load object.Shown in Figure 3 is four-way driving structure schematic representation, by the next command signal U of computer _iExport to power amplifier 1, operation servovalve 2, and then operation pressurized strut 3 promote piston output displacement X ₁, X ₂, X ₃, X ₄Measure four passage pressurized strut cavity pressure P by pressure transducer ₁, P ₂, P ₃, P ₄, export to signal selector 6 simultaneously, choose four passage pressurized strut cavity pressure average P through signal selector 6 _CPAnd compare with one of them and to obtain pressure difference value P _e=P _Cp-P _i, feed back to this passage through balance function device 8 again and make each channel pressure trend consistent, simultaneously by position feedback 10 with the Displacement Feedback of comprehensive output shaft 9 to power amplifier 1, constitute the position closed loop system, the dispute of alleviation interchannel power reaches Synchronous Transmission.Pressurized strut cavity pressure average also can be chosen intermediate pressure value and compare.

In the present invention, remove a plurality of passage pressurized strut cavity pressure average P of employing _CPOutside the equilibrium, also regard multichannel servodrive as the multivariate system, the multivariate decoupling technology has been eliminated the power dispute that causes because of interchannel difference in the employing modern control theory, at last equilibrium is combined with decoupling zero and proposed balanced decoupling zero strategy and designed signal selector 6 and balance function device 8, reached the optimal design of system, the synchronous transmission device of being developed is through test, and its synchronous difference power only is 1.4%.Remove the safety measure that the present invention has in addition also considered system, in case a certain passage is stuck, detector 4 can detect automatically, and this passage is promptly isolated, and the thresholding of detector is P _c, when | P _e| 〉=P _cThe time, coupling cock valve 5 is opened, pressurized strut two chamber UNICOMs, and affiliated passage is promptly cut, is unlikely to the stuck entire equipment that causes of this passage and damages.

The present invention will reach below that the interchannel transmission is consistent analyzes explanation by " software servo ":

1. the inconsistent cause analysis of interchannel transmission

Single pass transmission Block Diagram as shown in Figure 4, multichannel Block Diagram is as shown in Figure 5.

Wherein: U _iRepresent the signal that computer is exported, perhaps represent the input signal of power amplifier

K _q=K _aK _v(K _dThe unconventional and unrestrained device gain of expression power, K _vThe gain of expression servovalve)

T _vThe time constant S of expression servovalve represents laplace operator

K _mThe expression valve control pressurized strut K that comprehensively gains _hExpression pressurized strut output gain

K _sTransmission rigidity between expression piston and comprehensive output shaft

X _tExpression piston output displacement X _pRepresent the output of comprehensive output shaft

F _iExpression ouput force D _lExpression damping constant A represents piston area

d _iRepresent interchannel difference

Wherein interchannel difference d _iWhen theory is analyzed the concentrated reflection d _iOn, the transfer function that so can set up four-way is:

$X_P\left(S\right)=\frac{K_h{K}_m{K}_q}{G\left(S\right)}(U+\frac{1}{4}\underset{i=1}{\overset{4}{\mathrm{\Σ}}}{d}_i)---\left(1\right)$

Wherein:

G(S)＝S(T _mS+1)(T _VS+1)+K _mK _h[K _hK _qAS(T _VS+1)]+K _h(T _mS+1)D _lS

Ouput force F _iTransfer function:

$F_i\left(S\right)=\frac{K_h{K}_m{K}_q}{G\left(S\right)}(U+d_i)+---\left(2\right)$

$\frac{K_m{K}_h[S(T_{m}S+1)(T_{h}S+1)+K_h{K}_m[K_b{K}_q+\mathrm{AS}(T_{V}S+1)\left]\right]}{G\left(S\right)(T_{m}S+1)(T_{V}S+1)}(d_i-\frac{1}{4}\underset{j=1}{\overset{4}{\mathrm{\Σ}}}{d}_j)$

Being not difficult to find out from (2) formula, mainly is ouput force F _iDifference, i.e. F ₁, F ₂, F ₃, F ₄Difference causes the transmission difference of each passage, ouput force F _iThe comprehensive output shaft 9 that do not coexist on cause the dispute of power, and ouput force F _iDifference mainly is the difference d of each passage _iDifference cause, particularly when the gain K _mK _qNumerical value is very big, makes capable dispute aggravation, removes in addition in (2) formula there is one in difference

Link, this link K _m, T _mGenerally bigger, so this link is equivalent to an integral element, integral element exists, and very easily makes ouput force F _iDisperse.

2. solve the inconsistent measure of interchannel

(1) balancing technique

Basic thought is that the pressure signal to each passage carries out signal and selects (average or intermediate value), again the pressure of this passage and the difference of average (or intermediate value) are fed back to this passage by a balance function K (S), make each channel pressure reach unanimity (seeing shown in Figure 2), alleviate the dispute of interchannel power, reach Synchronous Transmission.

Equilibrium can be set up following transfer function to pressurized strut cavity pressure average:

$X_P\left(S\right)=\frac{K_m{K}_q{K}_h}{G\left(S\right)}(U+\frac{1}{n}\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{d}_i)---\left(3\right)$

$F_i\left(S\right)=\frac{K_h{K}_m{K}_q{D}_{l}S}{G\left(s\right)}(U+d_i)+$

$\frac{K_m{K}_q[S(T_{m}S+1)(T_{v}S+1)+K_h{K}_m[K_b{K}_q+\mathrm{AS}(T_{v}S+1)]-K_m{K}_q{K}_{h}K\left(S\right)D_{l}S}{G\left(S\right)[(T_{m}S+1)(T_{v}S+1)+K_m{K}_{q}K\left(S\right)}(d_i-\frac{1}{4}\underset{i=1}{\overset{4}{\mathrm{\Σ}}}{d}_j)$

This shows and introduce after the equalising network that compare with (2) formula, the high gain link obviously descends, integral element has also thoroughly been eliminated, and can not reduce the global stiffness of system, so balancing technique is a kind of effective way of solution power dispute problem.

But it is optimum how to select equalising network to be only? the present invention proposes the method that a kind of optimum equalization decoupling zero network gives meter first, has realized optimal control.

(2) decoupling technology

Can know by inference from the mathematical model of system, the coupling function F (S) of ouput force is:

Wherein:

$a=\frac{3}{(T_{m}S+1)(T_{v}S+1)}+\frac{K_h{D}_{l}S}{G\left(S\right)}$

$b=\frac{-1}{(T_{m}S+1)(T_{v}S+1)}+\frac{K_h{D}_{l}S}{G\left(S\right)}$

$F_i\left(s\right)=\frac{K_m{K}_q{K}_h{D}_{l}S}{G\left(S\right)}(U+d_i)+$

$\frac{K_m{K}_q[S(T_{m}S+1)(T_{v}S+1)+K_m{K}_h[K_b{K}_q+\mathrm{AS}(T_{v}S+1)\left]\right]}{G\left(S\right)(T_{m}S+1)(T_{v}S+1)}(d_i-\frac{1}{4}\underset{j=1}{\overset{4}{\mathrm{\Σ}}}{d}_j)---\left(6\right)$

From coupling function as can be seen: coupling is that interchannel exists crosslinked interference.

The present invention proposes to adopt pressure feedback decoupling zero scheme, and Principles of Network figure as shown in Figure 6.

If decoupling zero battle array D (s) is:

According to the decoupling zero control theory, the transfer function matrix after the decoupling zero should be diagonal form and nonsingular, and according to system's control requirement, system still keeps single pass performance after the decoupling zero.

So the ssystem transfer function matrix should be after the decoupling zero:

In the formula $\mathrm{\β}\left(s\right)=\frac{K_h{K}_m{K}_q{D}_{l}S}{G\left(s\right)}$

Draw the decoupling zero battle array by the theory derivation:

Wherein:

$A\left(s\right)=\frac{T_m{T}_{v}A}{K_m{K}_h{K}_q{\mathrm{<figure-callout\; id="2"\; label="D\; l\; S"\; filenames="C0313705400121.png"\; state="\{\{state\}\}">D</figure-callout>}}_l}{S}^{}{}^2+\frac{T_{m}A+(1+K_h{K}_{m}A){\mathrm{AT}}_v}{K_m{K}_h{K}_q{D}_l}S+\frac{(1+K_h{K}_{m}A)A}{K_m{K}_h{K}_q{D}_l}+\frac{K_{b}A}{D_{l}S}$

Obviously, ordinary circumstance:

K _mK _qK _hK _l＞＞T _mT _vA

K _mK _qK _hD _l＞＞[T _m+(1+K _lK _mA)T _v]A

So when realizing, the decoupling zero network can be designed to simply:

$D\left(s\right)=(a_0+\frac{a_1}{S}\mathrm{\&phi;}\left(n\right))$

In the formula:

$a_0=\frac{(1+K_h{K}_{m}A)}{K_h{K}_m{K}_q{D}_l}\&ap;\frac{A^2}{K_q{D}_l}$

$a_1=\frac{K_{b}A}{D_l}$

As seen the decoupling zero network only is proportional-plus-integral and parameter a in the conclusion ₀, a ₁Selection be easy to realize that this shows, adopting the pressure feedback decoupling zero is comparatively desirable decoupling zero mode.

Yet, adopting this decoupling zero mode, how the conclusion in that the situation of parameter model abbreviation draws guarantees that its robustness still has certain problem.

(3) equilibrium solution RMD fing mode decoupling

The front says that the basic reason that the exertin dispute produces is that interchannel exists crosslinked interference, therefore, equalising network is realizing that decoupling zero is that the thought of optimum design is correct, and the decoupling zero network has just solved the robustness problem of decoupling zero control if can adopt balanced way to realize.

By formula (7) as seen, equalising network is if adopt the average equilibrium promptly to finish the calculating of φ (n), and assurance K (s)=A (s) (shown in Fig. 2,5), then can realize decoupling zero control.

Because what adopt is the proportional-plus-integral equilibrium, system's static state is full decoupled, and equalising network itself to the power dispute with regard to restricted effect, so adopt equalized form to realize decoupling zero, decoupling zero is controlled has been had certain robustness.

The optimum equalization decoupling zero network theory that proposes according to the present invention, we test actual triple channel servo-actuating device, and the gained empirical curve is as shown in Figure 7.From figure as can be known, do not add balanced decoupling zero timing (anterior three lines), 188.6 kilograms of maximum dispute power add that to become its dispute power maximum value of a line substantially behind the compensation correction be 2.64 kilograms, and the attenuation ratio of dispute power is $\frac{2.64}{185}=1.43\%.$

As seen add after the optimum equalization decoupling zero network, elimination power dispute is promptly thorough again rapidly, and solution power dispute problem is guaranteed that the servo-driven conformity of multichannel has obtained breakthrough.

Claims (7)

1, a kind of multi-channel synchronous hydraulic servo transmission device, it is characterized in that: described hydraulic servo transmission device is made up of power amplifier (1), servovalve (2), pressurized strut (3), detector (4), coupling cock valve (5), signal selector (6), comparator (7), balance function device (8), comprehensive output shaft (9) and position feedback (10), by the next command signal U of computer _iExport to power amplifier (1), operation servovalve (2), and then operation pressurized strut (3) promote piston output displacement X _tMeasure pressurized strut cavity pressure P by pressure transducer _i, export to signal selector (6) simultaneously, choose a plurality of passage pressurized strut cavity pressure average P through signal selector (6) _CpAnd compare with one of them passage pressurized strut cavity pressure and to obtain pressure difference value P _e=P _Cp-P _i, feed back to this passage through balance function device (8) again, simultaneously by position feedback (10) with the Displacement Feedback of comprehensive output shaft (9) to power amplifier (1), constitute the position closed loop system, make each channel pressure trend consistent, alleviate the dispute of interchannel power, reach Synchronous Transmission.

2, multi-channel synchronous hydraulic servo transmission device according to claim 1 is characterized in that: during for four-way, by the next command signal U of computer _iExport to power amplifier (1), operation servovalve (2), and then operation pressurized strut (3) promote piston output displacement X ₁, X ₂, X ₃, X ₄Measure four passage pressurized strut cavity pressure P by pressure transducer ₁, P ₂, P ₃, P ₄, export to signal selector (6) simultaneously, choose the pressure average P of four passages through signal selector (6) _CpAnd compare with one of them passage pressurized strut cavity pressure and to obtain pressure difference value P _e=P _Cp-P _i, feed back to this passage through balance function device (8) again, simultaneously by position feedback (10) with the Displacement Feedback of comprehensive output shaft (9) to power amplifier (1), constitute the position closed loop system, make each channel pressure trend consistent, alleviate the dispute of interchannel power, reach Synchronous Transmission.

3, according to claim 1,2 described multi-channel synchronous hydraulic servo transmission devices, it is characterized in that: adopt a plurality of passage pressurized strut cavity pressure average P _CpCarry out equilibrium and relatively realize balanced control.

4, according to claim 1,2 described multi-channel synchronous hydraulic servo transmission devices, it is characterized in that: servodrive adopts " software servo " to reach synchronous drive.

5, according to claim 1,2 described multi-channel synchronous hydraulic servo transmission devices, it is characterized in that: whether detector (4) sense channel automatically is stuck, and the thresholding of detector is P _c, when | P _e| 〉=P _cThe time, coupling cock valve (5) is opened, pressurized strut two chamber UNICOMs.

6, according to claim 1,2 described multi-channel synchronous hydraulic servo transmission devices, it is characterized in that: the multivariate decoupling technology has been eliminated the power dispute that causes because of interchannel difference in signal selector (6) and balance function device (8) the employing modern control theory, and its synchronous difference power is less than 1.4%.

7, multi-channel synchronous hydraulic servo transmission device according to claim 1 is characterized in that: power unit also can be the hydraulic rotating motor.

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