Method 105

Angular position control test

1. Test Objective

Detect the repeatability, accuracy, and resolution of the turntable angular position control system.

2. Test instruments

Verified digital display device for a measured shaft angular position measurement system.

3. Test Environment Conditions

Ambient temperature: 20±2℃ (for accuracy higher than ±2”);

20±3℃ (for accuracy higher than ±5”);

Relative humidity: ≤70%;

Vibration isolation requirements: The turntable under test shall be placed on a vibration isolation foundation, with no severe vibrations or impacts around it;

Electromagnetic field requirements: There should be no strong electromagnetic interference in the vicinity of the test site.

4. Test Methods

When the turntable is in angular position automatic control mode, the turntable axis is automatically rotated to a predetermined angular position by a given position command.

4.1 Repeatability and accuracy test of angular position control

Sequentially issue angular position commands for angles θi = i × 360°/7 , causing the turntable to rotate one revolution in both the forward and reverse directions. After the system stabilizes at each position, the digital display value of the angular position measurement system is read. The readings are recorded as a 11 , ..., a 17 , a21, ..., a27

4.2 Angular position control resolution

The measured axis is in angular position control state and positioned at any angular position. Record the digital display value d1 of the angular position measurement system of the measured axis. The minimum position command equivalent is given by the turntable angular position control system, and record the digital display value d2 of the angular position measurement system.

5. Data Processing and Result Evaluation

5.1 Angular position control repeatability

5.1.1 Data Processing

In the formula: e1.i — The difference between the measured values of adjacent test points when the measured shaft rotates forward, (");

e2.i — The difference between the measured values of adjacent test points when the measured shaft rotates reversed, (").

N—Number of position measurement points.

5.2 Angular position control accuracy

5.2.1 Data Processing

In the formula: Uα0 — angular position control accuracy when the measured axis rotates forward, (");

U 2α0 — Angular position control accuracy when the measured axis rotates reversed, (").

5.2.2 Result Evaluation

The angular position control accuracy is the maximum value between U1 α0i and U2 α0i .