Quartz accelerometer is widely used in inertial navigation system, and is one of the important measurement sensitive components in the precision guidance of inertial navigation system. Its working principle is to convert the sensitive acceleration of the carrier into the corresponding electrical value and transmit it to the navigation control computer, and then obtain the displacement value of various attitude of the carrier after integral calculation. The stability of quartz flexible accelerometer also directly affects the stability of inertial navigation system. Through the analysis of the output model of quartz accelerometer, it is found that the main factors affecting the stability of quartz flexible accelerometer are the stability indexes of offset value and scale factor.The products represented by the scale factor of ER-QA-01A is 1.1~1.5mA/g bias ≤1mg and the scale factor of ER-QA-03A is 1.3±0.2mA/g bias ≤ ±3mg meet the high requirements for the bias and scale factor.
The main test methods of quartz accelerometer include position tumbling in gravity field, precision centrifugal test, precision line vibration test, dynamic test by electric simulation method, etc. The actual testing process is often one or more combinations of testing. As shown in figure 1.The Quartz accelerometer's fixed fingers in the forcing cells are normally kept at the same potential as that of the movable frame. When the digital self-test input is activated, the sensor changes the voltage on the fixed fingers in these forcing cells on one side of the moving plate. This potential creates an attractive electrostatic force, causing the sensor to move toward those fixed fingers. The entire signal channel is active; therefore, the sensor displacement causes a change in XOUT. The sensor’s self-test function verifies normal operation of the sensor, interface electronics, and accelerometer channel electronics.
In the testing process of the accelerometer, a set of accurate acceleration values are usually input to the accelerometer, a set of corresponding accelerometer output values are measured, and the accelerometer model equation is obtained through calculation. In the actual use process, the output of the accelerometer is measured, and the acceleration value felt by the accelerometer (and its carrier) is calculated by using the calibrated accelerometer model equation.
Why is the quartz accelerometer being tested
Simply , it is necessary to understand the performance of the quartz accelerometer. Quartz accelerometer is affected by temperature, vibration and other environmental loads and the characteristics of the internal components of the accelerometer, the parameters will have nonlinear drift with time, and the long-term repeatability will change.
Test index
1. Test the size of each coefficient item in the accelerometer model equation;
2. Test the changes of the coefficients in the accelerometer model equation with external conditions (such as time, temperature, vibration, shock, air pressure, electric pressure, electromagnetic, noise, etc.);
3. Test the response of the accelerometer to the input signal (such as bearing capacity, reaction speed, sensitive range, etc.);
4. Test the life of the accelerometer (such as working life, storage life, etc.) and reliability indicators.
As mentioned above, the pendulum is a key component of the quartz flexible accelerometer, and its performance and quality play a key role in the technical performance index of the quartz flexible accelerometer. The performance and quality of the pendulum, to a large extent, depends on the quartz material made of the pendulum. Carry out the analysis and research on the influence of quartz material properties on the performance of quartz flexible accelerometer, use advanced detection means to further analyze the indicators of the material, verify the influence of quartz material on the performance of quartz flexible accelerometer through swing processing and quartz flexible accelerometer performance test, and determine the technical performance requirements of quartz flexible accelerometer on quartz material.
More Technical Questions
1.Calibration Method of Accelerometer
2.How to Improve the Long-term Stability of the Quartz Accelerometer?
3.What is the Purpose of the Accelerometer Senor?
4.What are the Advantages and Disadvantages of Quartz Accelerometers?
5.What is the Effect of Temperature Coefficient on Quartz Accelerometer?
6.What is Sensitivity and Measurement Range in Quartz Accelerometer?
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