Research on tolerance optimal allocation method for a 6-DOF series manipulator based on DH-parameters

In order to provide theoretical reference for the determination of structural parameter tolerance at the initial design stage of manipulator body structure’s precision, so as to improve the geometric positioning accuracy of manipulator end-effector, a parameter tolerance optimal allocation method based on the optimal precision model is proposed. This method does not need tolerance-cost model and relevant statistical information, reaching the balance between accuracy and manufacturing cost. This study takes ROKAE XB7 6-DOF series manipulator as the research object. Based on the synthesis error of extremum model and optimal precision model, genetic algorithm is used to optimize the tolerance allocation of DH-parameters. Through the simulation analysis and experimental verification of the positioning error of the manipulator, the results show that the designed precision of the manipulator can meet the design requirements. The tolerance optimal allocation method proposed in this study can be applied to the geometric precision design of the 6-DOF series manipulator.