In order to improve the low output accuracy caused by the elastic deformations of the branch chains,a finite element-based dynamic accuracy analysis method for parallel mechanisms is proposed in this paper.First,taking a 5-prismatic-spherical-spherical(PSS)/universal-prismatic-universal(UPU)parallel mechanism as an example,the error model is established by a closed vector chain method,while its influence on the dynamic accuracy of the parallel mechanism is analyzed through numerical simulation.According to the structural and error characteristics of the par-allel mechanism,a vector calibration algorithm is proposed to reduce the position and pose errors along the whole motion trajectory.Then,considering the elastic deformation of the rod,the rigid-flexible coupling dynamic equa-tions of each component are established by combining the finite element method with the Lagrange method.The elastodynamic model of the whole machine is obtained based on the constraint condition of each moving part,and the correctness of the model is verified by simulation.Moreover,the effect of component flexibility on the dimension-less root mean square error of the displacement,velocity and acceleration of the moving platform is investigated by using a Newmark method,and the mapping relationship of these dimensionless root mean square errors to dynamic accuracy is further studied.The research work provides a theoretical basis for the design of the parameter size of the prototype.

Yanbiao Li;Zesheng Wang;Chaoqun Chen;Taotao Xu;Bo Chen

College of Mechanical Engineering,Zhejiang University of Technology,Hang-zhou 310023,China;Key Laboratory of E&M,Ministry of Education&Zheji-ang Province,Zhejiang University of Technology,Hangzhou 310023,China

中国机械工程学报

[1]Yanbiao Li;Zesheng Wang;Chaoqun Chen;Taotao Xu;Bo Chen-.Dynamic Accuracy Analysis of a 5PSS/UPU Parallel Mechanism Based on Rigid-Flexible Coupled Modeling)[J].中国机械工程学报,2022(02):77-90

5PSS,elastodynamic

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