Research On Pre-stressed Parallel Six-axis Accelerometer

With the diversified development of information,sensors in the field of measurement,control and automation are more and more demanding.Six-axis accelerometer as a sensor that can get the full acceleration information of moving objects is of great concern.Through a comprehensive study on the six-axis accelerometer at home and abroad,a pre-stressed parallel six-axis accelerometer is proposed,and the configuration design,mathematical modeling,performance index and structural optimization are conducted.A type of 8-SPS parallel topology configuration is proposed as the elastic body of pre-stressed parallel six-axis accelerometer,and the piezoelectric ceramics can be pre-tightened by adding the disc spring,locking nut and sleeve.The forward kinematics solution of parallel mechanism is obtained with the help of numerical method,and dynamics equations of the sensor system are conducted based on Newton-Euler method.Six acceleration components are completely decoupled by using the numerical algorithm,which has a high decoupling precision.Force compatibility equations are derived through the inherent constraints of the parallel mechanism to solve the axial force of eight branched chains,which determined the magnitude of preload.The fundamental frequency model of the sensor is derived based on the Lagrange method,and the natural frequency and modal shape can be obtained by matrix iteration method.Compared with the ANSYS simulation data,the error of the fundamental frequency is not more than 4.17%.The sensitivity model about the structural parameters is derived from the above-mentioned compatibility equations,which is in agreement with the ADAMS simulation results.In order to solve the issue of multi-objective optimization effectively,a function of comprehensive performance index is proposed based on the fundamental frequency model and sensitivity model,and a set of structural parameters combination with the relative optimal comprehensive performance is obtained by orthogonal test,which has important reference value for the structural optimization design and quantitative evaluation of sensors.Finally,a prototype of a pre-stressed parallel six-axis accelerometer is designed,and then the correctness of the established mathematical models are verified through concrete experiments.