The Theory And Simulation Analysis Of Stiffness Modeling Of Redundant Spoke Six-dimensional Force Sensing Mechanism

This paper mainly researches the configuration design,stiffness modeling method,and finite element simulation of the spoke-type parallel six-dimensional force sensing mechanism based on the orthogonal decoupling isotropic configuration.Systematic research is focused on stiffness modeling methods such as static stiffness modeling,nonlinear continuous stiffness modeling,and flexible ball joint size optimization,which provides new ideas and methods for the theoretical research of stiffness modeling of spoke-type parallel six-dimensional force sensing mechanisms..Firstly,the simplest stiffness model of the rotating configuration spoke-type parallel six-dimensional force sensing mechanism is established by using the line vector expression method.Based on this,the branch direction and hinge position are determined based on the orthogonal decoupling constraints,and the six-dimensional force is further constructed Perceptual mechanism static mapping matrix.This method can quickly screen all the isotropic configurations of spoke-type parallel six-dimensional force sensing mechanisms and summarize them.Secondly,the static stiffness of the redundant eight-branch six-dimensional force sensing mechanism screened in the previous chapter is considered,considering the flexible measurement unit.Starting from the flexibility matrix of the flexible ball hinge and flexible beam elements,a flexible measurement single branch stiffness matrix is established based on the deformation superposition principle.Based on this,based on the deformation coordination conditions and the simplest stiffness model of the six-dimensional force sensing mechanism,a flexible parallel six The overall stiffness model of the dimensional force sensing mechanism,and then a static mapping model between the internal forces at the measurement points and the six-dimensional external load of the redundant eight-branch six-dimensional force sensing mechanism considering the flexible measurement unit is constructed.Thirdly,in order to solve the problem that the large deformation of the flexible mechanism when subjected to a large load will greatly affect the stiffness model of the force-sensing mechanism,a non-linear continuous stiffness modeling method based on the iterative step loading idea is proposed.The process of mechanical deformation of the mechanism is made continuous by section loading,and a static mapping matrix considering the mechanical deformation of the mechanism is derived.Through finite element simulation verification,it can be found that compared with the static stiffness modeling method,the nonlinear continuous stiffness modeling method has a slight improvement in modeling accuracy.Finally,in view of the problem of coupling errors between force-sensitive components caused by flexible ball joints,the mapping matrix of force sensing mechanism based on ideal spherical joints is compared,and the key dimensions parameters of flexible ball joints are analyzed in depth based on iterative method to measure the accuracy of force sensing mechanism.The influence rules are generated,the optimal size parameters are screened,and the effectiveness of the optimization is verified by finite element simulation.Finally,a virtual calibration and error analysis were performed on the optimized six-dimensional force sensing mechanism,and the sensor product rendering was drawn.