Study on dimension synthesis optimization of five-bar metamorphic mechanism

Planar five-bar mechanism has been widely studied as the executive mechanism of the walking part of the robot leg. In order to improve the precision of dimension synthesis optimization of five-bar metamorphic mechanism, a new dimension synthesis method of five-bar metamorphic mechanism is proposed. By constructing a metamorphic cell into the planar five-bar mechanism, the presented method makes the five-bar mechanism have two configurations of crank-slider mechanism and crank-rocker mechanism. Firstly, according to the round-trip characteristics of the slider in the crank-slider mechanism, the working interval of the two configurations is divided and the method of metamorphic configuration is determined. Subsequently, the optimization model of the five-bar metamorphic mechanism is constructed, the coordinate formula of the target trajectory point is derived, the optimization design variables, objective functions and constraints are determined, through this rigorous process determine the dimension comprehensive optimization parameters of the five-bar metamorphic mechanism. Then, different optimization algorithms are used to simulate different classical target trajectories and the optimization results of the three mechanisms are compared. Moreover, the continuity between configurations is verified and the feasibility of the method is proved. The results underscore the superiority of the proposed method over traditional single configuration designs, which enhances the versatility of the five-bar mechanism, avoids the error caused by the two-degree-of-freedom drive, improves the working condition fitness of the five-bar mechanism and provides a theoretical basis for the study of the comprehensive dimension optimization of the five-bar metamorphic mechanism.