CN104074813B - A kind of controlling method of advanced prevention hydraulic shock power - Google Patents

Abstract

The present invention relates to a kind of controlling method of advanced prevention hydraulic shock power, comprise the following steps: according to the control frequency f of hydraulic system _minwith test requirements document loading speed v _yand the service behaviour of hydraulic system, the initial loading times coefficient k of setting hydraulic system, calculates the initial loading times t of hydraulic system _c, initial loading maximum acceleration a _max; Loading speed v is required again according to hydraulic pressure test _y, maximum acceleration a _max; Hydraulic system must meet actual loading speed v simultaneously and equal requirement loading speed v in hydraulic pressure test loading process _y, actual loading acceleration a be less than or equal to maximum acceleration a _max, and maximum acceleration a _maxthe mode loading of segment increasing can be adopted, the generation of hydraulic shock power can be prevented.The present invention can prevent concrete sample (component) consequent cracking, scrap, and can also avoid causing secondary injury to personnel, environment, thus improves reliability, the efficiency of whole system.

Description

A kind of controlling method of advanced prevention hydraulic shock power

Technical field

The present invention relates to the controlling method for hydraulic system in electromechanical control field, particularly a kind of controlling method can preventing hydraulic shock power in advance.

Background technique

A complete hydraulic system is made up of power system, data processing system, control system, executive system, auxiliary system and hydraulic oil 6 parts.Power system converts the mechanical energy of prime mover the pressure energy of liquid to; Data processing system processes input instruction signal, measuring system data, the action of command control system; Control system controls in hydraulic system and the pressure of regulates liquid, flow and direction; The pressure energy of liquid is converted to mechanical energy by executive system, drives load to do straight reciprocating motion or rotation motion; Auxiliary system then mainly refers to fuel tank, oil purifier, oil pipe and pipe joint, seal ring, quick release coupling etc. in hydraulic system; Hydraulic oil is the working medium of transferring energy in hydraulic system.The low-limit frequency f of hydraulic system _mini.e. control frequency is generally determined by the electrohydraulic control frequency characteristic of control system, and detection frequency in hydraulic system, data operation process frequency can higher than Systematical control frequency f _min.Whether the valve in control system can be divided into continuously by aperture is only had 2 points (standard-sized sheet, complete shut-down) state and has continuous aperture two class, the size of its valve opening describes relative value and absolute value two kinds of modes, as the valve opening relative value of full off state, absolute value describe and be 0, the valve opening relative value of full-gear is described as 100%, be described as 1 or 100 or other positive integer for being greater than 100 with absolute value.

Hydraulic system starting suddenly, shut down, speed change or commutation time, valve port is closed suddenly or action stops suddenly, and due to the effect of working fluid and moving element inertia, make the surge pressure that in system, instantaneous formation is very high, this phenomenon is just referred to as hydraulic shock.During generation hydraulic shock, in system, the peak value of local compression change can reach several times of normal operating pressure, system is not only very easily caused to shake, and likely make seal wear, pipeline burst, weld cracking, cause system leakage of oil, pressure meter, flowmeter also may be made malfunctioning, pressure relay and sequence valve mistaking signal, pressure regulator valve, Flow valve damage etc., even likely make the load of concrete sample (component) directly reach capacity load and cause sample (component) to be scrapped.Hydraulic shock had both affected the reliability of hydraulic system self, concrete sample (component) may be caused again to ftracture, scrap, also may cause secondary injury to personnel, environment.

The existing limitation of hydraulic shock technology that prevents is: be carry out physical modifications for the power system of hydraulic system, executive system, control system, auxiliary system and hydraulic oil mostly, the improvement still Shortcomings of controlling method, the drawback of hydraulic shock fails to eradicate.

Summary of the invention

For the deficiency that above-mentioned prior art exists, object of the present invention aims to provide a kind of controlling method of advanced prevention hydraulic shock power, control according to hydraulic pressure test requirement loaded load (hereinafter referred to as loading) speed, the actual hydraulic system loading speed and acceleration and newly-increased maximum acceleration of recording, and maximum acceleration a _maxthe mode loading of segment increasing can be adopted, the generation of hydraulic shock power can be prevented.Both improve the reliability of hydraulic system self, and concrete sample (component) consequent cracking can have been prevented again, scrap, and can also avoid causing secondary injury to personnel, environment, thus improve reliability, the efficiency of whole system.

For achieving the above object, the technological scheme that the present invention takes is: a kind of controlling method of advanced prevention hydraulic shock power, comprises the steps:

(1) according to the control frequency f of hydraulic system _minwith test requirements document loading speed v _yand the service behaviour of hydraulic test system, the initial loading times coefficient k of setting hydraulic system, calculates the initial loading times t of hydraulic system _c,; Wherein, k be more than or equal to 2 positive integer;

(2) according to step (1) described test requirements document loading speed v _y, the initial loading times t of hydraulic system _c, calculate the maximum acceleration a of initial loading _max; Wherein, described hydraulic pressure test requires loading speed v _y, maximum acceleration a _max, hydraulic system meets actual loading speed v simultaneously and equals test requirements document loading speed v in hydraulic pressure test loading process _y, actual loading acceleration a be less than or equal to maximum acceleration a _max;

(3) to the maximum acceleration a of hydraulic system in the initial loading stage _maxadopt the loading of segment increasing mode, described segments i is the positive integer for 2 or 3; Hydraulic system also should meet the actual loading speed v in each stage in initial loading phase process simultaneously _iequal the requirement loading speed v in this stage _yi, actual loading acceleration a _ibe less than or equal to the maximum acceleration a in this stage _maxi.

The controlling method of a kind of advanced prevention hydraulic shock power of the present invention is mainly for the hydraulic shock power of hydraulic system instantaneous formation when unexpected speed change or commutation, and its control object can be load, also can be strain, displacement.

Compared with prior art, the invention has the beneficial effects as follows and fully use existing control technique and performance, according to the loading speed v that hydraulic pressure test requires _y, actually record hydraulic system loading speed v and acceleration a and newly-increased maximum acceleration a _maxcontrol, and maximum acceleration a _maxthe mode loading of segment increasing can be adopted, the generation of hydraulic shock power can be prevented, both improve the reliability of hydraulic system self, can reduce again and secondary injury is caused to concrete sample (component), thus improve efficiency and the quality of whole system.

Embodiment

Embodiment one:

A kind of control object of controlling method of advanced prevention hydraulic shock power is load:

The electronic-hydraulic servo pressure testing machine of one 500 tons, Systematical control frequency f _minfor 150Hz, test requirements document loading speed v _yfor 18.0kN/s, maximum valve opening is 30000, and after testing machine starts, oil cylinder moves to test specimen distance test (DT) machine top board 2mm place time-out and reset by load.General hydraulic pressure test is when starting to test, all first will perform automatch---for ensureing the slow loading of oil cylinder, the valve opening of the initial loading of computer control is 1000, when its load is 1000N, computer controlled system will be automatically converted to actual loading speed v and equal requirement loading speed v _y, and the acceleration a simultaneously meeting actual loading is less than or equal to maximum acceleration a _max, and the initial velocity v of setting oil cylinder ₀=0, the initial loading times coefficient k of hydraulic system is 30000, hydraulic system maximum acceleration a _maxadopt 3 segmentations 235 to open and increase progressively control.

According to the condition of the above hydraulic pressure test, because control frequency cycle T _minfor:

T _min＝1/f _min(s)(1)

The initial loading times t of hydraulic system _c:

t _c＝k×T _min＝k×(1/f _min)＝k/f _min＝30000/150＝200(s)(2)

Assuming that the at the uniform velocity acceleration of hydraulic system, if the time of initial 1st, 2,3 be respectively t _c1, t _c2, t _c3, then:

t _c1＝t _c×5/10＝200×5/10＝100(s)(3)

t _c2＝t _c×3/10＝200×3/10＝60(s)(4)

t _c3＝t _c×2/10＝200×2/10＝40(s)(5)

If the final velocity of initial 1st, 2,3 section is respectively v ₁, v ₂, v ₃, and:

v ₃＝v _y＝18.0kN/s(6)

v ₁＝2×v ₃/10＝3.6(kN/s)(7)

v ₂＝(2+3)×v ₃/10＝9.0(kN/s)(8)

If the maximum acceleration of initial 1st, 2,3 section is respectively a _max1, a _max2, a _max3, then have:

v ₁＝v ₀+a _max1×t _c1(9)

v ₂＝v ₁+a _max2×t _c2(10)

v ₃＝v ₂+a _max3×t _c3(11)

By v ₀=0 and above-mentioned 1 formula substitute into 7 formulas, have after arrangement:

$a_{\max 1}=\frac{v_1}{t_{c1}}=\frac{3.6}{100}=0.036(\mathrm{kN}/s^2)=36(N/s^2)---\left(12\right)$

In like manner:

$a_{\max 2}=\frac{V_2-V_1}{t_{c2}}=\frac{9.0-3.6}{60}=0.09(\mathrm{kN}/s^2)=90(N/s^2)---\left(13\right)$

$a_{\max 3}=\frac{V_3-V_2}{t_{c3}}=\frac{18-9.0}{40}=0.225(\mathrm{kN}/s^2)=225(N/s^2)---\left(14\right)$

Embodiment two:

A kind of control object of controlling method of advanced prevention hydraulic shock power is strain:

The electro-hydraulic servo universal testing machine of one 30 tons, Systematical control frequency f _minfor 150Hz, tension test requires that the rate of straining of loading is 6 μ ε/s, and maximum valve opening is 40000, suspends also loading clearing, strain capacity resets when oil cylinder moves to appropriate location after testing machine starts.General hydraulic pressure test is when starting to test, all first will perform automatch---for ensureing the slow loading of oil cylinder, the valve opening of the initial loading of computer control is 1000, when its load is 100N, the rate of straining v being automatically converted to actual loading is equaled the rate of straining v of requirement loading by testing machine system _y, and the acceleration a simultaneously meeting actual loading is less than or equal to maximum acceleration a _max, and the initial velocity v of setting oil cylinder ₀=0, the initial loading times coefficient k of hydraulic system is 22500, hydraulic system maximum acceleration a _max2 segmentation 2:8s are adopted to increase progressively control.

According to the condition of the above hydraulic pressure test, because control frequency cycle T _minfor:

T _min＝1/f _min(s)(1)

The initial loading times t of hydraulic system _c:

t _c＝k×T _min＝k×(1/f _min)＝k/f _min＝22500/150＝150(s)(2)

Assuming that the at the uniform velocity acceleration of hydraulic system, if the time of initial 1st, 2 be respectively t _c1, t _c2, then:

t _c1＝t _c×8/10＝150×8/10＝120(s)(3)

t _c2＝t _c×2/10＝150×2/10＝30(s)(4)

If the final velocity of initial 1st, 2 section is respectively v ₁, v ₂, and:

v ₂＝v _y＝6με/s(5)

v ₁＝v ₂×2/10＝1.2(με/s)(6)

If the maximum acceleration of initial 1st, 2 section is respectively a _max1, a _max2, then have:

v ₁＝v ₀+a _max1×t _c1(7)

v ₂＝v ₁+a _max2×t _c2(8)

By v ₀=0 and above-mentioned 1 formula substitute into 5 formulas, have after arrangement:

$a_{\max 1}=\frac{v_1}{t_{c1}}=\frac{1.2}{120}=0.01(\mathrm{\μ\ϵ}/s^2)---\left(9\right)$

In like manner:

$a_{\max 2}=\frac{V_2-V_1}{t_{c2}}=\frac{6-1.2}{30}=0.16(\mathrm{\μ\ϵ}/s^2)---\left(10\right)$

The specific embodiment of the invention is in sum only the preferred embodiment of the present invention, is not intended to limit the restriction of scope.Therefore, any do within technical characteristics of the present invention change, modification, substitute, combination or simplify, all should be equivalence substitute mode, be included within protection scope of the present invention.

Claims (1)

1. a controlling method for advanced prevention hydraulic shock power, is characterized in that, comprise the steps:

(1) according to the control frequency f of hydraulic system _minwith test requirements document loading speed v _yand the service behaviour of hydraulic test system, the initial loading times coefficient k of setting hydraulic system, calculates the initial loading times t of hydraulic system _c; Wherein, k be more than or equal to 2 positive integer;

(2) according to step (1) described test requirements document loading speed v _y, the initial loading times t of hydraulic system _c, calculate the maximum acceleration a of initial loading _max; Wherein, described hydraulic pressure test requires loading speed v _y, maximum acceleration a _max, hydraulic system meets actual loading speed v simultaneously and equals test requirements document loading speed v in hydraulic pressure test loading process _y, actual loading acceleration a be less than or equal to maximum acceleration a _max;

(3) to the maximum acceleration a of hydraulic system in the initial loading stage _maxadopt the loading of segment increasing mode, segments i is the positive integer for 2 or 3; Hydraulic system also should meet the actual loading speed v in each stage in initial loading phase process simultaneously _iequal the requirement loading speed v in this stage _yi, actual loading acceleration a _ibe less than or equal to the maximum acceleration a in this stage _maxi.