Abstract:The parallel mechanisms with analytic positive position solution and partial motion decoupling are of great benefit to subsequent research such as error analysis, workspace solution, singularity analysis and stiffness analysis, dynamic performance analysis, motion trajectory planning and control. Firstly, a class of two 2T1R parallel mechanisms with analytic positive position solutions and partial motion decoupling were proposed according to the design theory and method of parallel mechanism (PM) based on position and orientation characteristics equation (POC). The main topological performance, including position and orientation characteristics, degree of freedom and coupling degree calculation, was performed. Secondly, according to the method for kinematics modeling based on topological characteristics by the author, the analytic positive solution of one of the PMs was solved in detail. Then, based on the derived position inverse solution, the workspace, singular configuration, velocity and acceleration variation of the PM were analyzed. Finally, the difference between the two PMs in the above various performance indexes was compared and analyzed. Based on this, the preferred PM was selected. Because of its simple structure, good kinematics and dynamic performance, it had potential applications in the manufacturing, which was especially suitable for handling, grabbing, loading and unloading of workpieces with large length in the longitudinal direction. The research result laid a theoretical foundation for the dynamic analysis and prototype development of the preferred PM.