Design Method Of Acceleration Sensor's Dynamic Compensator Based On Reference-model

Acceleration sensor has many advantages such as low power consumption, small volume, and it has been widely applied to acceleration measurement occasions. With the development of measurement technology, the requirement of its capability has enhanced. The accelerometer should have fast response speed and wide working frequency band. Due to the acceleration sensor structure characteristics, its maximum measuring frequency is limited. When the accelerometer's working band is smaller than the upper frequency, it has large measuring error and cannot meet the measurement requirements. For example, the frequency of shock acceleration, generated from crash test is great. But the existing accelerometer's working band is smaller than the upper frequency, so it has large measuring error and cannot meet the measurement requirements. In order to reduce its dynamic measurement error, it is very urgently needed to compensate its dynamic error.Concatenating a dynamic compensator filter is a common method to compensate the dynamic error of accelerometer. The existing compensating method takes sensor as a second-order model. The compensator's structure and parameters are calculated by Zero-pole assignment or identification algorithm. These methods can compensate the sensor to some extent. Acceleration sensor's second-order dynamic model can accurately describe the dynamic performance of low frequency scope, but in the higher frequency scope, it can not describe the dynamic performance accurately. The second order compensator can't achieve ideal compensation effect. For compensating the dynamic error comprehensive and accurately, it is need to build the acceleration sensor's high-order model and design the corresponding high-order dynamic compensator. So it is very important to design high-order compensator filter, which is based on accelerometer's high-order model and measurement indexes.In this paper, an accelerometer's high-order dynamic compensator design method is proposed to improve the accelerometer's working frequency band and dynamic response speed. The accelerometer's high-order modeling method is studied and the four-order ARX model of accelerometer is built by its experimental data; the method of calculating the order of the compensator base on the pole and zero of the model is studied; the parameter of the compensator is identified by error white algorithm; the method of using colored Kalman filter to eliminating compensator's noise is proposed; finally, the accelerometer's dynamic compensator is built.The experimental results show that high-order ARX model is able to describe its dynamic characteristics comprehensively; the order of the compensator calculated by the pole and zero of the model is the best; the parameters of the compensator identified by Error White algorithm (EWC) can get the unbiased estimation. The high-order dynamic compensator, compared with the low-order compensator, can improve its dynamic characteristics better.