Research On A Piezoelectric Six-axis Accelerometer Based On 6-SPS Parallel Mechanism

Six-axis accelerometer, which is a kind of inertial sensors getting kinetic parameters in the field of robots, aerospace and the like, is an electromechanical integration system that concentrates multi-discipline. Key technical problems about six-axis accelerometer have not been worked out thoroughly, and there are a few researches on it at home and abroad. This thesis presented a method of designing piezoelectric six-axis accelerometer using parallel mechanism as the structure of sensor with the advantages of high sensitivity, high precision, large measurement range, broad working frequency band and etc.In this paper, theory and experimental research about multi-axis accelerometer in the world were deep analyzed and synthesized. Based on these, problems of six-axis accelerometers existing were summarized. Screw theory, vector mechanics, and analytical mechanics were used to analyze the kinematics and dynamics of the transducer, and the system's vibration differential equation was established. Sensitivity of the sensor was defined in this thesis, and the analytic expression was detailedly deduced, meanwhile the relationship of structural parameters and sensitivity was analyzed through observing curve of sensitivity. Deriving the mode equation of the sensor system by means of linearization of dynamic equations, and the six natural frequencies being developed according to the theory of matrix iteration.The varying law of the fundamental frequency based on the structural parameters of the sensor is presented, and ADAMS software is employed to testify the validity of theoretical results. The concept of compliance accuracy ratio of flexible spherical hinge is first proposed in this paper, and the study of structural optimization design on the flexure hinge is given. After manufacturing the prototype of the sensor and developing measurement system based on LabVIEW 8.6 , experiment was done, and the result which confirms the validity of the thesis was satisfactory. At last the decoupling property of the transducer is analyed by topology's method.The research work in this dissertation establishes the theoretical foundation for the development of six-axis accelerometers, and it is of great significant with the practical values.