Research Of A High-frequency Simulation Table With Stewart Parallel Structure

Stewart parallel manipulator has been widely used in modern industry fieldssuch as flight simulator, parallel robots, high-precision machine tool etc., for itsstiffness in mechanical structure, a larger payload to robot weight and high positionaccuracy. Though hydraulic driving Stewart parallel manipulator has lots ofadvantages compare with serial mechanism, its low frequency and bandwidthrestricts its use in some high-frequency fields.The high-frequency simulation table in this paper can overcome the deficiencyof low-frequency of Stewart parallel mechanism. And reach higher frequencymeeting up with some systems’ high-frequency request.This paper first introduces and analyzes the structure and parameters of thesimulation table. Based on the analysis, kinematics of the table are researched,giving the forward kinematics, reverse kinematics solutions of hydraulic cylinders’position, and also the velocity and acceleration. The Jacobian matrix betweenvelocity of upper platform and velocity of hydraulic cylinders is calculated, and thismatrix is important for further dynamics analysis.This paper builds system’s dynamic model with Kane’s method, it first deducesthe Jacobian matrix of respective components from their motion relation, thencalculates the partial velocity and partial angle velocity of each link’s velocity forgeneralized velocity. After that generalized active force and generalized inertiaforce of active force and inertia force in the generalized velocity direction are alsocalculated. Then dynamic equations of multi-rigid-body system are obtainedthrough Kane’s method, corresponding M programs are also given.Besides the theoretical model, a parametric model is built with ADAMSsimulation software for system’s kinematic and dynamic simulation. The results ofthe simulation are compared with theoretical results verifying the reliability of themodel and theoretical analysis.At last, simulation table’s workspace and singularity are analyzed, givingfixed-attitude-position space and fixed-position-attitude space which are thefoundations of structure design. Natural frequency and stiffness of this table are alsoanalyzed for further understanding of the table’s dynamic performance.