MEMS Test System Design For Position-attitude In Process Of Space Shuttle

Motion characteristics of displacement and attitude acquired under simulated releasing test environment is significant to verify the design of releasing mechanism of a product assembly and test its performance in the development of satellite and rocket.Optical testing method is mostly adopted in the conventional test,but its application limitations have gradually appeared with the diversification and complication of structure and motion forms of the assembly,e.g.,movement process in cylinder before out of cylinder,self-rotation after out of cylinder and deployment of stretched out structure of the assembly in releasing test.High accuracy test and comprehensive measurement of the test parameters cannot be fulfilled by only optical testing method.This paper brings forward a design thought of a posit ion-attitude measurement system mainly integrated by MEMS linear accelerator and angular rate sensor.The measurement system takes high-frequency sampling on the linear acceleration along three orthogonal-axis and angular rate of a moving object,coverts the sampled data into digital signal through A/D digital analog inverter,uses ARM+FPGA circuit to complete data compensation and saving,then calculates the data transmitted from the sensors by navigation solvers to achieve the measurement of position velocity and attitude angle.This research started from the actual test application demand of the product,analyzed and raised the sampling rate,memory space and indexes of configuration dimensions of the measurement system,combined the motion characteristics and measurement requirements of released object,chose the vibration-resistant and shock-resistant packaging structure for the sensors of the position-attitude measurement system.The measuring accuracy of the position-attitude measurement system is optimized by sensing variation correction of temperature sensor and digital analog compensation according to the basic principle and temperature drift characteristics of MEMS linear accelerator and angular rate sensor.The definition of initially set parameters in different coordinates systems is designed,and navigation calculation of displacement velocity and attitude angles of moving parameters are made by quaternion method.In conclusion,a set of IMU position-attitude measurement system with high sampling rate and high accuracy which is applicable to simulated releasing test is developed and designed in this paper considering the test requirements,test environment,test application features,implementation method and integrated data analysis.