CN102829908A - Method for measuring comprehensive interference torque of three-axis air-floating platform - Google Patents

Abstract

The invention discloses a method for measuring a comprehensive interference torque of a three-axis air-floating platform. The method comprises the following steps: regulating the balance of the three-axis air-floating platform, marking at a certain position of the air-floating platform, providing an initial speed for the air-floating platform around a certain axis, measuring the time of rotating the mark for a circle and recording the time as T1; continuously rotating the air-floating platform, recording the time of continuously rotating the changed mark and recording the time as T2; obtaining the comprehensive interference torque M by calculation according to the formula; reversely rotating the air-floating platform and repeating the steps 2-4 to obtain the reverse comprehensive interference torque. The method has the characteristics of convenience in realization of high-precise measurement, simple principle, convenience and practicability, easy realization and low cost and is also suitable for measuring the comprehensive interference torque of a single-axis air-floating platform.

Description

Three-axis air-bearing table integrated interference torgue measurement method

Technical field

The present invention relates to measuring technique, is exactly three-axis air-bearing table integrated interference torgue measurement method specifically.

Background technology

The air film that three-axis air-bearing table relies on pressurized air between air-bearing and bearing seat, to form; The simulation stage body is floated; Thereby realize approximate friction free relative motion condition, with spacecrafts such as analog satellite in the outer space the very little mechanical environment of suffered disturbance torque.As the spacecraft motion simulator; Three-axis air-bearing table carries out the performance that satellite control system full physical simulation experiment can checking system, facts have proved that not only checking has vital role to the attitude of flight vehicle control system to utilize air floating table to carry out emulation; And can significantly improve the efficiency-cost ratio of aircraft; Reducing risk, shorten the R&D cycle, is important means and the method in the spacecraft development process.

The integrated interference moment of three-axis air-bearing table is a key technical index; Measuring three-axis air-bearing table integrated interference moment is the needs of air floating table parameter calibration; Also be based on an important previous work of the l-G simulation test of three-axis air-bearing table; Especially for high-precision pilot system, need to realize the high-acruracy survey of three-axis air-bearing table integrated interference moment.

Retrieve through document; Zhang Zhen army, Dong Yunfeng etc. " utilize the new method of momenttum wheel test air platform disturbance torque " at paper, and (see " computer measurement and control ", 2008 years, 16 rolled up for the 8th phases; Page number 1122-1124) in according to the moment of momentum theorem; Utilize the disturbance torque of the startup accelerating performance mensuration air floating table of momenttum wheel, but this method need dispose high-precision flywheel, cost is high, Project Realization is difficult.Eastwards, Yang Qingjun, Baogang, Wang Zuwen etc. (see Acta Astronautica at paper " three air floating platforms often are worth the analysis and the compensation of disturbance torque "; 2009; 30 the 2nd phases of volume, page number 448-452) proposed to measure the method for calculating disturbance torque in through the dynamics inverting, and through the physical pendulum cycle derivation of equation estimation equation of normal value disturbance torque; But this method need be set up precise math model, is not easy to Project Realization.Yang Xiubin, golden light, Xu Kai etc. propose to record each angular velocity constantly in real time with optical fibre gyro in paper " automatic adjustment of three-axis air-bearing table and disturbance torque test "; Angular velocity varies according to each moment stage body calculates disturbance torque then; This method need dispose optical fibre gyro; Cost is high, and because the high-precision measurement of the very difficult realization of the accuracy limitations of optical fibre gyro at present.

Summary of the invention

The object of the present invention is to provide that a kind of principle is simple, cost is low, the measuring method of the three-axis air-bearing table integrated interference moment of easy to operate, easy Project Realization.

The objective of the invention is to realize like this:

Described three-axis air-bearing table integrated interference torgue measurement method, step is following:

Step 1: with the three-axis air-bearing table adjustment, do a mark in certain position of air floating table stage body, give initial velocity around vertical axes of air floating table then, velocity magnitude is confirmed according to the measurement needs;

Step 2: measure this mark and rotate a circle the used time, and be designated as T1;

Step 3: air floating table continues rotation, writes down this mark and continues the used time that rotates a circle, and be designated as T2:

Step 4:

calculates integrated interference moment M according to formula, and wherein J is the air floating table that records the in advance moment of inertia around turning axle.

Step 5: let the air floating table reverse rotation, and repeat step 2～four, obtain reverse integrated interference moment.

Three-axis air-bearing table integrated interference torgue measurement method of the present invention; Operating speed sensitive equipment not, the metering outfit that only takes time is convenient to realize high-precision measurement; And simple, convenient and practical, the easy realization of principle, expense are low, and this method also is applicable to the measurement of single-axle air bearing table integrated interference moment.

Description of drawings

Fig. 1 is a three-axis air-bearing table integrated interference torgue measurement principle schematic;

Fig. 2 is a three-axis air-bearing table indicatory Sign Detection stage body rotation complete cycle synoptic diagram;

Fig. 3 is an optoelectronic switch sensor measurement three-axis air-bearing table swing circle synoptic diagram.

Embodiment

For example the present invention is described further below in conjunction with accompanying drawing.

Embodiment 1, in conjunction with Fig. 1, and three-axis air-bearing table integrated interference torgue measurement method of the present invention, principle is following:

Because the singularity of three air supporting rotary bodies, the selection of speed sensitive device and design proposal is difficulty relatively, this programme can obtain the integrated interference moment of three-axis air-bearing table under the situation of direct measuring speed not:

At first, let air floating table then under various disturbance torque effects at initial position of stage body marked, low speed is free rotate continuously 2 weeks or more than, and continuous recording is through the time of mark position.Know at oneself and the time according to record, then can calculate disturbance torque under the situation of air floating table moment of inertia.At first one week of horizontal direction low speed rotation (angular displacement s=360 °), write down used time t ₁Rotated for second week (angular displacement s=360 °) then continuously, write down used time t ₂Because the special construction of three-axis air-bearing table, its integrated interference moment are uniformly, therefore can be approximately even deceleration circular motion to rotating freely of stage body, so can calculate:

The mean angular velocity of first revolution is

The mean angular velocity of second revolution is

The speed in the moment in the middle of the average velocity of uniformly accelerated motion just in time equals.That is from the

to

the time spent for the

Therefore can get:

$\frac{\mathrm{<figure-callout\; id="2"\; label="s\; t"\; filenames="HSA00000772599400011.png"\; state="\{\{state\}\}">s</figure-callout>}}{t_{}}={\stackrel{\&OverBar;}{v}}_2={\stackrel{\&OverBar;}{v}}_1+a(\frac{t_1}{2}+\frac{{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000772599400011.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{2})=\frac{s}{t_1}+a\frac{t_1+{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000772599400011.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{2}$

That is:

$\frac{s}{t_2}-\frac{s}{t_1}=a\frac{t_1+{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000772599400011.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{2}$

Substitution s=360 °=2 π, final abbreviation can get:

$a=\frac{4\mathrm{\&pi;}(t_1-t_2)}{t_1{t}_2(t_1+t_2)}$

Also can be according to the direct compute angular acceleration of the relation of acceleration in the uniformly accelerated motion and speed, that is:

$a=\frac{{\stackrel{\&OverBar;}{v}}_2-{\stackrel{\&OverBar;}{v}}_1}{\frac{t_1+{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HSA00000772599400011.png"\; state="\{\{state\}\}">t</figure-callout>}}_2}{2}}=\frac{4\mathrm{\&pi;}(t_1-t_2)}{t_1{t}_2(t_1+t_2)}.$

By formula M=Ja, wherein M is a moment, and J is a moment of inertia, and a is an acceleration, can get integrated interference moment:

$M_Z=M=J\&CenterDot;\frac{4\mathrm{\&pi;}(t_1-t_2)}{t_1{t}_2(t_1+t_2)}$

In the actual test of three-axis air-bearing table disturbance torque; What be concerned about is integrated interference moment, can measure the disturbance torque around this turning axle with said method through the adjustment turning axle; Repeatedly measure the variation of observing numerical value, the distribution situation of disturbance torque in the time of can recording the different rotary axle thus.

Embodiment 2, in conjunction with Fig. 2-3, and three-axis air-bearing table integrated interference force measuring method of the present invention, the time measurement of described rotation complete cycle is achieved in that

(1) manual time-keeping method

As shown in Figure 2; The position is done a mark respectively near under three-axis air-bearing table stage body and the three-axis air-bearing table platform; Can detect the swing circle of three-axis air-bearing table, write down the time interval of double markers align, thereby record the swing circle of standard air float body with stopwatch.

In the manual time-keeping method; Relevant by the measuring accuracy of formula

disturbance torque and rotation inerttia precision, time measurement precision; The following analyst's part work and part study second of precision regularly: because three-axis air-bearing table real work rotating speed is not higher than 1 °/s usually; Typical rate is 0.2 °/s; With 1 °/s is that example is analyzed: rotate all 360s consuming time; Manual work is declared time error and is not more than 1s (through evidence, average error is in 0.2s), so the measuring error of time is less than 0.3%.This precision can satisfy the measurement requirement of high precision three-axis air-bearing table.

(2) optoelectronic switch sensor chronometry

As shown in Figure 3; Add a black strip mark at the stage body edge; The optoelectronic switch sensor is installed at the correspondence markings place under the three-axis air-bearing table platform, and sensor links to each other with computing machine, the timing of exporting control computer through the signal of detection optoelectronic switch sensor; Thereby detect the swing circle of stage body automatically, be shown in the following figure.

The stage body rotation, when mark process sensor, computing machine is just noted the moment of this point, so just can calculate the time interval t of double record ₁And t ₂Thereby, calculate acceleration.

In the above-mentioned clocking scheme, the manual time-keeping method is a method that engineering feasibility is stronger, without any need for other equipment, as long as on stage body, do a mark, can realize measuring with stopwatch.Optoelectronic switch is measured the swing circle scheme and can be realized with normal optical electric switch sensor coupled computer, low price, simple to operate, timing is accurate.

Claims (1)

1. the measuring method of a three-axis air-bearing table integrated interference moment is characterized in that step is following:

Step 1: with the three-axis air-bearing table adjustment, do a mark in certain position of air floating table stage body, give initial velocity around vertical axes of air floating table then, velocity magnitude is confirmed according to the measurement needs;

Step 2: measure this mark and rotate a circle the used time, and be designated as T1;

Step 3: air floating table continues rotation, writes down this mark and continues the used time that rotates a circle, and be designated as T2;

Step 4:

calculates integrated interference moment M according to formula, and wherein J is the known air floating table moment of inertia around turning axle;

Step 5: let the air floating table reverse rotation, and repeat step 2～four, obtain reverse integrated interference moment.

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