Structural Design, Kinematics And Fault Repair Of Reconfigurable Six-dimensional Acceleration Senso

With the continuous development of science and technology and the continuous improvement of people’s requirements for understanding the objective world,it is more and more important to detect the six-dimensional motion parameters of objects.The traditional six dimensional acceleration sensor has a single configuration.When facing the complex and changeable environment such as more noise or large change of input acceleration,it often can not meet the measurement requirements.In view of this,in order to make the sensor adapt to the rapidly changing working environment,this paper designs a reconfigurable six-dimensional acceleration sensor which can switch freely among the four configurations of 9-4,9-3,12-4 and12-6.The main research contents are as follows:(1)A variable cell mass block structure which can realize the reconstruction of parallel six-dimensional acceleration sensor is designed,which includes a central sphere,an arc slider and a corner piece.By twisting the arc slider and rotating angle piece,the layout and orientation of the branch chain can be changed,so as to realize the configuration reconstruction of the six-dimensional acceleration sensor.(2)With the amplitude and frequency of the input acceleration are constantly changing,the input and output results of the sensor are systematically simulated.The relationship curve between the relative error introduced by ignoring the relative motion and the amplitude and frequency of the midline acceleration and angular acceleration of the input motion is obtained.Furthermore,by calculating and comparing the condition number of parallel mechanism Jacobian matrix,the root of the difference of decoupling results under different measurement conditions is excavated and revealed.(3)A "four step method" is proposed to analyze the relationship between basic excitation,structural parameters and singular performance.In the first step,the forward dynamic equations of four configurations are established and solved by using Newton Euler method;The second step is to calculate and solve the forward kinematics equation of each configuration by introducing the "tetrahedral element",and combine the forward dynamics equation to deduce the functional relationship between the base excitation and the relative position and orientation of the mass block;In the third step,based on the direct differential method,the Jacobian matrix of elastomer structure is derived;The fourth step is to calculate the condition number of Jacobian matrix and draw the scatter diagram of singular surface.Accordingly,the mapping among basic excitation,structural parameters and singular performance is constructed.(4)Using Hooke’s law and piezoelectric theory,the charge coordination equations of four sensor configurations are derived respectively.Using the "output redundancy method" and based on the charge coordination equation,the self diagnosis and self repair of 9-3 and 9-4configurations are analyzed.Due to the large number of coordination equations of 12-6 and12-4 configurations,double branch and three branch fault processing algorithms based on redundant output information of sensors for 12-6 and 12-4 configurations are constructed based on "coordinated closed chain method" and "coordinated equation group method" respectively.Then,through the virtual prototype experiment,the relationship between the actual self diagnosis rate of the sensor and the threshold is analyzed.Finally,the comprehensive decoupling errors of 12-4 and 12-6 configurations before and after fault repair are calculated to test the effectiveness and feasibility of the repair algorithm.This paper provides new ideas and insights for improving the adaptability and reliability of six-dimensional acceleration sensor,and the conclusions and results provide theoretical guidance for the synthesis and optimization of elastomer topology of six-dimensional acceleration sensor.