CN104454789A - Field calibration method for flow parameters of electro-hydraulic servo valve test system - Google Patents

Abstract

The invention relates to a field calibration method for flow parameters of an electro-hydraulic servo valve test system. The field calibration method comprises the following steps: carrying out field calibration of linear error on low-range sections of the flow parameters of the electro-hydraulic servo valve test system by using a standard electro-hydraulic flow servo valve; obtaining the linear error within the range (10 percent below zero to10 percent) of the flow parameters of the calibrated system. Compared with a traditional calibration method, the field calibration method has the characteristics of being simple and convenient in operation, short in calibration period, high in data processing speed and the like, and meanwhile, the consistence between a calibration state and a use state of the calibrated system is ensured.

Description

A kind of field calibration method of electrohydraulic control test system flow parameter

Art

This technology belongs to flow measurement field, relates to a kind of field calibration method of electrohydraulic control test system flow parameter.

Goal of the invention

Object of the present invention is as follows:

1, flow field calibration problem is solved;

2, the bidirectional linear calibration of electrohydraulic control test system flow parameter lower range section is realized;

3, the problem that the Linearity error solving electrohydraulic control test system flow parameter zero point cannot be calibrated;

4, a kind of low cost is found, the short period, simple and efficient on-the-spot flow calibration steps.

Background technique

Electrohydraulic control test system is developed, for the special device of test traffic valve various performance parameters specially according to electrohydraulic control special technology condition.To leaking in electric flow quantity servovalve, zero partially, the important performance such as resolution, overlap test time, actual flow is that electrohydraulic control test system measures less than 10% of the upper limit, and is twocouese use.

Traditional calibration steps unloads after being removed by flowmeter to send laboratory investment, and there are the following problems for the method:

1, the required precision of flowmeter itself is higher, to reach to reach this, laboratory is selected by (10% ~ 100%) of the school flowmeter survey upper limit usually as its range ability, therefore gained Linearity error does not comprise the lower range section particularly zero point of less than 10%, and zero of valve product inclined and interior leakage characteristic is all record at zero crossings, cannot zero point be calibrated, just cannot ensure the accuracy of this feature measurement;

2, laboratory investment only carries out unidirectional calibration, and actual use is two-way, and align mode and using state there are differences;

3, the volume of flowmeter is large, Heavy Weight, repeated disassembled and assembled and transport not only difficulty but also very easily damage, and the censorship cycle is long, has a strong impact on product delivery progress.

In sum, in real work, often there is the phenomenon that the test result of different tests platform to same deck valve product differs greatly and can not pay in time because of system censorship product.

This programme is that emphasis solves and linearly calibrates for error at two-way calibration, zero point and the problem such as field calibration.The capital equipment that the program uses comprises standard electric flow quantity servovalve, static tester, test-bed body, X-Y recorder.Standard electric flow quantity servovalve output flow range is by (-10% ~ 10%) of calibration system measuring range, maximum tolerance is less than by 1/3 of calibration system maximum tolerance, meet volume passes requirement, and its repeatability and stability, all through making strict assessment, meet the condition as standardized product; Volume is little, lightweight simultaneously, is easy to carry, and remove and install conveniently, pole is applicable to field calibration; This programme is simple to operate, and data processing is easy, quick, can directly obtain, by the Linearity error of school flow parameter lower range section, having extremely strong use value.

Technological scheme: the specified output flow of standard electric flow quantity servovalve selected by this method is by 10% of the calibration system flow measurement upper limit, because its range is little, therefore greatly reduce with absolute error compared with calibration system, its maximum tolerance is less than by 1/3 of calibration system maximum tolerance; Whole calibration process only needs the test method according to product, records the no load discharge output characteristics of standard electric flow quantity servovalve, slightly deals with gained characteristic curve, just can directly obtain by the Linearity error of school flow parameter in this range section.Concrete operation step is as follows: a kind of field calibration method of electrohydraulic control test system flow parameter, is characterized in that, comprise the following steps:

Step 1, standard electric flow quantity servovalve is correctly installed on electrohydraulic control test system, and static tester control signal output line is connected with standard electric flow quantity servovalve terminal, flow simulation output terminal is connected with X-Y recorder Y input end, standard electric flow quantity servovalve current output terminal is connected with X-Y recorder X input terminal;

Each valve, the electrical switch of step 2, adjustment electrohydraulic control test system, be set to no load discharge characteristic test state;

Step 3, adjustment static tester export as triangular signal, and amplitude corresponds to standard electric flow quantity servovalve rated current, and frequency is 1Hz, is then set to static tester automatically to export gear;

Step 4, by coordinate paper, be laid in X-Y recorder drawing area, centering is also fixing, and adjustment test pencil is to origin position, and adjustment X, Y-axis gear, make test pencil stroke take whole coordinate paper as far as possible;

Step 5, control static tester export the triangular signal of one-period, and draw out the no load discharge characteristic curve of standard electric flow quantity servovalve one-period, in winding shape, one-period is-100% → 0 → 100% → 0 →-100%;

Step 6, drafting nominal flow capacity curve, namely the mid point line of loop curve is returned, then with 100% rated current on no load discharge characteristic curve and-100% rated current corresponding points for end points, the straight line connecting two-end-point gained is nominal flow gain curve, coordinate paper reads the maximum deviation of nominal flow capacity curve and nominal flow capacity gain curve, and Linearity error is calculated as follows:

${\mathrm{\λ}}_L=\frac{\mathrm{\Δ}{I}_{\mathrm{LM}}}{2I_n}\×100\%$

Wherein: λ _l---Linearity error;

Δ I _lM---the maximum deviation of nominal flow capacity curve and nominal flow capacity gain line;

I _n---the rated current of standard electric flow quantity servovalve;

Step 7, when gained Linearity error is less than this type valve product linearity EE Error Excepted, can judge that this electrohydraulic control test system flow parameter-10% ~ 10% range section linearity meets usage requirement.

Beneficial effect:

When operating by this method, each constituent element of electrohydraulic control test system is all in running order, is a kind of on-line calibration method, can ensures the conformity of align mode and using state; In a calibration process, the measuring device such as flow, electric current, pressure, temperature of electrohydraulic control test system and TT&C system all need to participate in, and have both calibrated the flow parameter of electrohydraulic control test system, and can verify again its combination property, and killed two birds with one stone simultaneously;

Use the calibration of standard electric flow quantity servovalve, without the need to dismounting flowmeter, easy and simple to handle, fast reliably, utilize on-the-spot oil sources to realize calibration, both economized on resources and again reduced calibration difficulty, and greatly can also shorten the alignment time;

Standard electric flow quantity servovalve volume is little, lightweight, is easy to carry, and without the need to other planning standard equipment, is extremely applicable to field calibration.

Embodiment:

In the inventive method, specifically there is following outstanding feature:

1, standard electric flow quantity servovalve is used to carry out field calibration to electrohydraulic control test system flow parameter;

2, the specified output flow of standard electric flow quantity servovalve is reached the standard grade by calibration system measurement 10%;

3, the no load discharge characteristic curve of drawing standard electricity flow quantity servovalve, realizes being calibrated by the bidirectional linear of school flow parameter;

4, the no load discharge characteristic curve of standard electric flow quantity servovalve, by zero point, therefore can obtain the Linearity error at place at zero point;

5, use X-Y recorder to carry out data logging, it is simple, quick that coordinate paper carries out data processing, and linearization error value directly can read and obtain.

The each critical component adopted is described below:

Static tester: be made up of parts such as dc amplifier, digital-to-analog conversion amplifier, differential amplifiers, for the display of Flow Characteristics of Electrohydraulic Servo Valve, Pressure characteristics, conversion and output, and provide the testing apparatus of the direct current (d.c.) needed for performance test for electrohydraulic control.

Test-bed body: for electric flow quantity Testing Performances of Hydraulic Servo Valve is developed specially, imitates the testing apparatus of valve product actual conditions; For tested valve product provides the tested media with certain pressure and flow; And possess flow, pressure, temperature test and output function.

X-Y recorder: be pen recorder again, can be depicted as function curve by the analogue signal of input.In this method, with the no load discharge characteristic curve of its drawing standard electricity flow quantity servovalve.

Choose a concrete situation below, the specific embodiment of the present invention be described in detail as follows:

By school electrohydraulic control test system:

Model: SC09;

Measure the upper limit: 150L/min;

Maximum tolerance: 1.5L/min;

Standard electric flow quantity servovalve

Model: FF102/10

Rated flow: 10L/min

Maximum tolerance: 0.4L/min;

Rated current: 10mA;

Linearity error: be not more than 4%

Step 1, standard electric flow quantity servovalve is correctly installed on electrohydraulic control test system, and static tester control signal output line is connected with standard electric flow quantity servovalve terminal, flow simulation output terminal is connected with X-Y recorder Y input end, standard electric flow quantity servovalve current output terminal is connected with X-Y recorder X input terminal;

Step 2, open electrohydraulic control test system oil inlet valve, oil return valve opens to maximum, opens static tester, selects knob to be adjusted to " Q-I " state its test parameter, observe static tester upward pressure, temperature, flow indication be all normal;

Step 3, adjustment static tester export as triangular signal, and output amplitude is 10V, is 10mA corresponding to standard electric flow quantity servovalve rated current, and frequency is 1Hz, is then set to static tester automatically to export gear;

Step 4, be the coordinate paper of 1mm by 20cm × 40cm, minimum calibration lattice, be laid in X-Y recorder drawing area, fixing after centering, origin position aimed at by adjustment test pencil, adjustment X-axis gear makes its resolution be about 0.5mA/cm, and adjustment Y-axis gear makes its resolution be 1L/min/cm;

Step 5, start test, control static tester export triangular signal, output order be-100%I _n→ 0 → 100%I _n→ 0 →-100%I _n, draw out the no load discharge characteristic curve of standard electric flow quantity servovalve one-period, in winding shape;

Step 6, draw out nominal flow capacity curve and nominal flow capacity gain curve, through observing, to find that maximum deviation is positioned at output flow be 0.8L/min place, and read the maximum deviation of two curves herein differs about 4 minimum calibration lattice, the Linearity error calculating this place is:

${\mathrm{\λ}}_L=\frac{4\×10/200}{2\×10}\×100\%=1\%$

Namely its Linearity error is less than the Linearity error permitted value of this type valve product, can judge that this electrohydraulic control test system flow parameter-10% ~ 10% range section linearity meets usage requirement.

Whole experimentation has two people to coordinate, do not remove any equipment of electrohydraulic control test system, electrohydraulic control test system is returned to upstate 1.5 hours used times altogether from preparing to reach a conclusion, the runnability of observing each measuring equipment is therebetween all normal again.

In electrohydraulic control product submitted for test afterwards, the stable performance of electrohydraulic control test system, the characteristic curves such as inclined, the interior leakage of valve product zero, resolution are clear and legible, and test result is intuitively credible, obtain client's accreditation.

Claims (1)

1. a field calibration method for electrohydraulic control test system flow parameter, is characterized in that, comprises the following steps:

Step 1, standard electric flow quantity servovalve is correctly installed on electrohydraulic control test system, and static tester control signal output line is connected with standard electric flow quantity servovalve terminal, flow simulation output terminal is connected with X-Y recorder Y input end, standard electric flow quantity servovalve current output terminal is connected with X-Y recorder X input terminal;

Each valve, the electrical switch of step 2, adjustment electrohydraulic control test system, be set to no load discharge characteristic test state;

Step 3, adjustment static tester export as triangular signal, and amplitude corresponds to standard electric flow quantity servovalve rated current, and frequency is 1Hz, is then set to static tester automatically to export gear;

Step 4, by coordinate paper, be laid in X-Y recorder drawing area, centering is also fixing, and adjustment test pencil is to origin position, and adjustment X, Y-axis gear, make test pencil stroke take whole coordinate paper as far as possible;

Step 5, control static tester export the triangular signal of one-period, and draw out the no load discharge characteristic curve of standard electric flow quantity servovalve one-period, in winding shape, one-period is-100% → 0 → 100% → 0 →-100%;

Step 6, drafting nominal flow capacity curve, namely the mid point line of loop curve is returned, then with 100% rated current on no load discharge characteristic curve and-100% rated current corresponding points for end points, the straight line connecting two-end-point gained is nominal flow gain curve, coordinate paper reads the maximum deviation of nominal flow capacity curve and nominal flow capacity gain curve, and Linearity error is calculated as follows:

${\mathrm{\λ}}_L=\frac{\mathrm{\Δ}{I}_{\mathrm{LM}}}{2I_n}\×100\%$

Wherein: λ _l---Linearity error;

Δ I _lM---the maximum deviation of nominal flow capacity curve and nominal flow capacity gain line;

I _n---the rated current of standard electric flow quantity servovalve;

Step 7, when gained Linearity error is less than this type valve product linearity EE Error Excepted, can judge that this electrohydraulic control test system flow parameter-10% ~ 10% range section linearity meets usage requirement.