CN103604562B - Two-dimensional rotating mechanism and testing device and method for rotational inertia of complex parts of two-dimensional rotating mechanism - Google Patents

Abstract

The invention relates to a test device and method for the moment of inertia of a two-dimensional rotating mechanism and its complex parts, including a simulated two-dimensional rotating mechanism and a lever dial indicator assembly; The rotating device for platform rotation, the velocity measuring system and the timing device are placed on the table of the air bearing platform; the simulated two-dimensional rotating mechanism includes an azimuth rotating device and a pitch rotating device, the azimuth rotating device includes a two-dimensional turntable rotor and a turntable stator, and the pitch rotating device includes The pitch axis and the bracket fixed on the rotor of the two-dimensional turntable; the lever dial indicator assembly includes a column and a lever gauge. One end of the lever gauge is fixed on the column, and the other end acts on the azimuth rotation device. The side angle system is installed in the air bearing platform . The technical problem of complex testing and low precision of the existing testing method for the moment of inertia is solved, and the present invention uses the characteristics of the micro-friction moment of the air-floating platform to test the moment of inertia of the simulated two-dimensional rotating mechanism.

Description

Device and method for testing moment of inertia of two-dimensional rotating mechanism and its complex components

technical field

The invention relates to a testing device and method for the moment of inertia of a two-dimensional rotating mechanism and its complex components.

Background technique

At present, there are generally two ways to obtain the moment of inertia of an object: for objects with simple shapes and uniform density distribution, the theoretical calculation method is generally used; for objects with complex shapes and irregular mass distribution, the actual measurement method is used. The actual measurement mainly uses elastic elements to form an oscillation system, and calculates the moment of inertia through the oscillation frequency of the system. Commonly used methods for measuring the moment of inertia are: compound pendulum method, torsion pendulum method, three-line pendulum method, single-line pendulum method, and falling body method. For the moment of inertia measured by the compound pendulum method, when the length-to-diameter ratio of the measured piece is greater than 15, its influence cannot be ignored; and when the vertical and parallel angle deviation is greater than 2°, the influence of the perpendicularity and parallelism between the longitudinal axis and the rotating axis should also be considered ; When the pendulum angle is 60°, the measurement vibration period error is ±6.8%, and the moment of inertia error reaches 40%. When the three-wire torsional pendulum method is used to measure a large mass of the test piece, the test piece is rotated and clamped upright, which makes installation difficult and poses safety hazards; at the same time, the position of the large test piece is unstable, which also affects the measurement accuracy. The single-line torsion method has the same problem. The accuracy of the falling body method can only reach 3% for the measured piece with large mass and high impulse.

Moment of inertia is the measure of inertia when a rigid body rotates, and its size reflects the difficulty of state change when a rigid body rotates. For any problem involving rotational dynamics, the moment of inertia is a key measurement parameter. The moment of inertia of the azimuth axis of the space two-dimensional rotating mechanism changes during the movement of the turntable, and changes with the change of the load pitch angle. Although there is a certain mathematical relationship between the two, there will be certain differences due to processing and installation errors. Therefore, it is necessary to conduct actual measurements to obtain the variation curve of the azimuth moment of inertia with different pitch angles, and provide basic parameters for momentum balance control and mechanical testing to determine the disturbance moment generated by the satellite. Due to the complex shape of the two-dimensional rotating mechanism, in addition, the moment of inertia of the azimuth axis will change with the change of the rotational position of the pitch axis. Therefore, the traditional measurement methods cannot meet the current test requirements due to the complexity and low precision of the test.

Contents of the invention

In order to solve the technical problems that the existing testing methods for moment of inertia are complex, low in precision and unable to meet the current testing requirements, the present invention provides a test device for moment of inertia of two-dimensional rotating mechanism and its complex components, which utilizes the micro-friction of the air flotation platform The characteristic of moment is to test the rotor azimuth and pitch axis moment of inertia of the two-dimensional turntable.

Technical solution of the present invention:

A test device for the moment of inertia of a two-dimensional rotating mechanism and its complex parts, which is special in that it includes an angle measuring system, a timing device, a speed measuring system, a simulated two-dimensional rotating mechanism and a lever dial indicator assembly;

The test platform includes an air flotation platform, a rotating device fixedly connected with the air flotation platform to drive the rotation of the air flotation platform, and the speed measurement system and the timing device are all located on the air flotation platform table;

The simulated two-dimensional rotation mechanism includes an azimuth rotation device and a pitch rotation device. The azimuth rotation device includes a two-dimensional turntable rotor and a turntable stator. The platform is fixedly connected, and the pitching rotation device includes a pitching shaft and a bracket fixed on the rotor of the two-dimensional turntable, the pitching shaft is arranged on the bracket and can perform pitching motion around the horizontal axis of the bracket;

The lever dial indicator assembly includes a column and a lever gauge, one end of the lever gauge is fixed on the column, and the other end acts on the azimuth rotation device,

The two-dimensional turntable rotor of the azimuth rotation device coincides with the rotary axis of the air bearing platform after being measured and adjusted by the lever dial indicator assembly;

The side angle system is installed in the air bearing platform.

The above-mentioned rotating device includes a fixed pulley, a weight and a stay rope, one end of the stay rope is fixed on the air floating platform, and the other end of the stay rope is connected with the weight through the fixed pulley.

The speed measuring system mentioned above is a rate gyroscope.

The test method for the moment of inertia of two-dimensional rotating mechanism and its complex parts is special in that it includes the following steps:

1) Measure the moment of inertia J ₀ of the non-rotating part of the turntable and the rotating plane of the air bearing platform:

1.1] Build the test device described in claim 1, only place the non-rotating part in the azimuth rotation device, and use the lever gauge to align the turntable stator with the air-floating platform;

1.2] Start the rotating device, so that the air bearing platform starts to rotate from a static state;

1.3] After rotating for t ₁ time, use the speed measurement system to collect the velocity V ₁ of the air floating platform at the moment;

1.4] Use the following formula to calculate the moment of inertia J ₀ of the non-rotating part of the azimuth rotating device and the rotating plane of the air bearing platform:

${\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}}{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

Wherein: M is a known moment, M=mg l, mg is the weight of the rotating device, and l is the distance between the connecting point of the rotating device and the air-floating platform from the rotating shaft of the air-floating platform;

ω ₀ is the acceleration value of the air bearing platform,

2) Measure the moment of inertia J _{A of the azimuth axis system when the pitch axis system of the simulated two-dimensional rotating mechanism is at the rotation angle A} :

2.1] Assemble the two-dimensional turntable rotor and pitch rotation device on the turntable stator after step 1.1], and use the lever table to adjust the azimuth axis of the two-dimensional turntable rotor to coincide with the rotation axis of the air-floating platform;

2.2] Turn the pitch axis to the angle A;

2.3] Start the rotating device so that the air-floating platform starts to rotate from a static state, and at the same time the angle measuring system measures the initial angle B ₀ of the air-floating platform;

2.4] When the angle measuring system measures the angle of the air-floating platform as B ₁ , stop the air-floating platform, and record the rotation t of the air-floating platform measured by the timing device and the velocity V of the air-floating platform measured by the speed measuring system at the same time;

2.5] Repeat steps 2.3]-2.4] n times;

2.6] Use the following formula to calculate the moment of inertia J _{A of the simulated rotating mechanism when the angle is A} :

${\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}$

$\mathrm{<span\; class="notranslate">\; \&omega;</span>}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\frac{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; .</span>$

A sampling interval is 5°, B ₁ -B ₀ =±5°, n is 5-6.

The speed measuring system mentioned above is a rate gyroscope.

The advantages that the present invention has:

The invention effectively solves the test of the moment of inertia of the two rotating shafts of the two-dimensional rotating mechanism. In the long run, this device will be a widely used testing instrument. It can not only replace the current existing products, but also has a testing method Simple, high measurement accuracy, high degree of automation and a series of advantages.

Description of drawings

Fig. 1 is the structural representation of measuring device of the present invention;

The reference signs are: 1-column, 2-lever table, 3-time system device, 4-rate gyroscope, 5-pitch device, 6-azimuth rotation device, 7-air floating platform, 8-pull rope, 9- Fixed pulley, 10-weight, 11-angle measuring system.

detailed description

As shown in Figure 1, a test device for the moment of inertia of a two-dimensional rotating mechanism and its complex parts, including an angle measurement system 11, a timing device 3, a speed measuring system, a simulated two-dimensional rotating mechanism and a centering component,

The test platform includes an air flotation platform 7, a rotating device fixedly connected with the air flotation platform to drive the rotation of the air flotation platform, the speed measurement system and the timing device 3 are located on the air flotation platform table,

The simulated two-dimensional rotating mechanism includes two parts: the azimuth rotating device 6 and the pitching device 5 , wherein the azimuth part includes the turntable stator and the turntable rotor. The two-dimensional rotating mechanism is placed on the table of the air-floating platform and fixedly connected with the air-floating platform through the turntable stator, and the pitching device is installed on the U-shaped bracket through the horizontal shaft system and can perform pitching motion around the horizontal axis;

The lever dial indicator assembly includes a column 1 and a lever indicator 2. One end of the lever indicator is fixed on the column, and the other end acts on the simulated two-dimensional rotating mechanism. The rotor of the two-dimensional turntable is adjusted by the centering component to coincide with the rotary axis of the air bearing platform. ; The side angle system 11 is installed in the air bearing platform.

The rotating device comprises a fixed pulley 9, a weight 10 and a stay rope 8, one end of the stay rope is fixed on the air floating platform, and the other end of the stay rope is connected with a weight through the fixed pulley.

Take the test of the moment of inertia of the azimuth shaft system as an example to illustrate the steps of the test method:

1) Measure the moment of inertia J ₀ of the non-rotating part of the turntable and the rotating plane of the air bearing platform;

1.1] Build the test device described in claim 1, only place the non-rotating part (rotary table stator) in the two-dimensional rotating mechanism, and use the lever gauge to align the stator with the air-floating platform;

1.2] Start the rotating device, so that the air bearing platform starts to rotate from a static state;

1.3] After rotating for t ₁ time, use the speed measurement system to collect the velocity V ₁ of the air floating platform at the moment;

1.4] Use the following formula to calculate the moment of inertia J ₀ of the non-rotating part of the turntable and the rotating plane of the air bearing platform:

${\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}}{{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}$

J ₀ ＝J _gas +J _set;

Among them, J is the known moment of inertia of the rotating shaft of the _air bearing table, and J _is the non-rotating part of the turntable.

Wherein: M is a known moment, M=mg l, mg is the weight of the rotating device (the weight of the weight), and l is the distance between the connecting point of the rotating device and the air-floating platform from the rotating shaft of the air-floating platform;

ω ₀ is the acceleration value of the air bearing platform,

2) Measure the moment of inertia J _{A of the azimuth axis system when the pitch axis system of the simulated rotating mechanism is at the rotation angle A} :

First, place the simulated two-dimensional rotating mechanism on the plane of the air-floating platform as shown in Figure 1, and use the fixed support around the air-floating platform to erect a lever gauge with a sensitivity of 0.01mm to detect the radial runout of the azimuth axis of the two-dimensional rotating mechanism. , adjust the rotary axis of the air bearing platform to be coaxial with the rotary axis of the measured two-dimensional turntable rotor;

Put the pitch axis at different angles with a sampling interval of 5°

A weight with a mass of m is connected to the rotating part of the air-floating platform through a fixed pulley and a pull rope. The distance between the connection point and the rotating shaft of the platform is l, and a tangential force is applied by the weight to make the air-floating platform rotate. The force direction is the same as that of the platform. The misalignment error of the rotating part at the tangent line of the force application point is not more than 5°, and the initial angle value of the air floating platform is recorded with the angle measuring system;

Use the rate gyroscope to record the rotation speed curve of the air bearing platform, and take the data with a difference of less than 5° from the initial angle of the platform for processing. The processing formula is:

${\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; A</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; m</span>}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; J</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}$

$\mathrm{<span\; class="notranslate">\; \&omega;</span>}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{<span\; class="notranslate">\; \&Sigma;</span>}}\frac{{\mathrm{<span\; class="notranslate">\; v</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}{{\mathrm{<span\; class="notranslate">\; t</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}}}}{\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; .</span>$

In the formula: M: known moment, in mg l, generally m is the mass of the weight;

ω: average value of platform acceleration;

V: the speed of rate gyro acquisition;

t: the time of time series collection;

J _A : Moment of inertia of the azimuth rotation part when the pitch axis is at angle A;

J ₀ : Moment of inertia of the rotating part of the air bearing platform and the stator of the turntable fixedly connected to it, that is, the non-rotating part of the azimuth axis of the turntable.

The turntable of the present invention can also be a component with complex shape. At this time, the component to be tested is placed on the plane of the air-floating platform, and a lever gauge with a sensitivity of 0.01mm is erected on the fixed support around the air-floating platform to detect the reference surface of the component rotation. The radial runout of the platform is adjusted to be coaxial with the rotary axis of the tested part. The precise moment of inertia of complex parts about their rotary axis or center of mass can be measured by the above method.

Claims (3)

1. the method for testing of two-dimensional rotation mechanism and complex parts moment of inertia thereof, is characterized in that, comprises the following steps:

1) the moment of inertia J of measuring circurmarotate non-rotating part and air floating platform rotational plane ₀:

1.1) build proving installation, only place the part of not rotating in directional rotating device, utilize lever meter by turntable stator and air floating platform centering;

Described proving installation comprise angle measuring system, time bulk cargo put, velocity-measuring system, test platform, simulating two-dimensional rotating mechanism and lever indicator assembly;

The wheelwork that the driving air floating platform that described test platform comprises air floating platform, be connected with air floating platform rotates, described velocity-measuring system and time bulk cargo put and be all positioned on air floating platform table top;

Described simulating two-dimensional rotating mechanism comprises directional rotating device and pitch rotation device, described directional rotating device comprises dimensional turntable rotor and turntable stator, described dimensional turntable rotor to be placed on air floating platform table top and to be fixedly connected with air floating platform by turntable stator, described pitch rotation device comprises pitch axis and is fixed on the epitrochanterian support of dimensional turntable, and described pitch axis to be arranged on support and can to do luffing around the transverse axis of support;

Described lever indicator assembly comprises column and lever meter, and described lever meter one end is fixed on column, and the other end acts on directional rotating device,

The dimensional turntable rotor of described directional rotating device is by overlapping with the revolving shaft of air floating platform after lever indicator assembly measurement adjustment;

Described angle measuring system is arranged in air floating platform;

Described wheelwork comprises fixed pulley, counterweight and stay cord, and one end of described stay cord is fixed on air floating platform, and the other end of described stay cord is connected with counterweight by fixed pulley;

1.2) start wheelwork, air floating platform is rotated from stationary state;

1.3) t is rotated ₁after time, velocity-measuring system is utilized to gather air floating platform speed V this moment ₁;

1.4) the moment of inertia J of non-rotating part and air floating platform rotational plane in following formula computer azimuth wheelwork is utilized ₀:

$J_0=\frac{M}{{\mathrm{\&omega;}}_0}$

Wherein: M is known moment, M=mgl, mg are the weight of wheelwork, and l is the distance of the tie point distance air floating platform rotating shaft of wheelwork and air floating platform;

ω ₀for air floating platform accekeration,

2) the moment of inertia J of azimuth axle when measure analog two-dimensional rotation mechanism pitch axis system is in corner A _a:

2.1) in step 1.1) after turntable stator on assemble dimensional turntable rotor and pitch rotation device, and the azimuth axis utilizing lever meter to adjust dimensional turntable rotor overlaps with the revolving shaft of air floating platform;

2.2) by pitch axes to angle A place;

2.3) start wheelwork, air floating platform is rotated from stationary state, angle measuring system records the initial angle B of air floating platform simultaneously ₀;

2.4) when the angle of angle measuring system measurement air floating platform is B ₁, stop air floating platform, during record, the air floating platform of system measurement device rotates the air floating platform speed V this moment of t and velocity-measuring system measurement simultaneously;

2.5) step 2.3 is repeated)-2.4) n time;

2.6) following formula is utilized to calculate when angle is for A, the moment of inertia J of simulation rotating mechanism _a:

$J_A=\frac{M}{\mathrm{\&omega;}}-J_0$

$\mathrm{\&omega;}=\frac{\underset{i=1}{\overset{n}{\&Sigma;}}\frac{v_i}{t_i}}{n}.$

2. the method for testing of two-dimensional rotation mechanism according to claim 1 and complex parts moment of inertia thereof, is characterized in that: A sampling interval is 5 °, B ₁-B ₀=± 5 °, n is 5-6.

3. the method for testing of two-dimensional rotation mechanism according to claim 1 and 2 and complex parts moment of inertia thereof, is characterized in that: described velocity-measuring system is rate gyro.