Three-translation parallel mechanism with excellent kinematic decoupling characteristics—topological design and analysis

SHE Xingyu; SHEN Huiping; MENG Qingmei; ZHU Xiaorong; LI Ju

doi:10.16578/j.issn.1004.2539.2025.12.003

Abstract：[Objective]Superior motion decoupling characteristics can significantly simplify the subsequent motion planning,control,error analysis,and dynamics analysis of mechanisms.However,current research on mechanisms possessing such characteristics remains relatively scarce.Therefore,based on the topology design theory and methodology of parallel mechanisms grounded in the position and orientation characteristic equation,a three-translation parallel mechanism with excellent motion decoupling and zero coupling degree was designed.[Methods]Firstly,a topological analysis of the proposed mechanism was conducted to obtain its position and orientation characteristic(POC)set,degree of freedom(DOF),coupling degree,and topological analytical expressions.Secondly,employing a kinematic modeling and analysis method based on topological features,symbolic forward and inverse position solutions of the proposed mechanism were derived.The forward solution was used to determine the mechanism's workspace,and singularities were identified by deriving the Jacobian matrix based on the inverse position solution equations.Thirdly,the dynamics performance of the proposed mechanism was analyzed using the principle of virtual work combined with the serial single-open-chain method.The required driving forces were solved,and the geometric parameters of the mechanism were optimized using a differential evolution algorithm.Finally,a conceptual design of an application scenario for the proposed mechanism was presented.[Results]The research results indicate that the workspace of the mechanism optimized by the differential evolution algorithm is significally expanded;the proposed mechanism,characterized by zero coupling degree,facilitates the derivation of symbolic forward and inverse solutions,and its motion decoupling capability substantially simplifies motion planning.