Optimization design of a compliant linear guide for high-precision feed drive mechanisms

This paper presents an optimal design of a compliant linear-guide mechanism for a high-precision feed drive. In this design, semi-circular flexural hinges are integrated with rigid-links to make lever mechanisms and parallelogram mechanisms to produce large amplification, increase structural rigidity, and reduce undesirable parasitic motion. Therefore it enhances the accuracy and enlarge the operational range of the mechanism. The design process includes five steps: (1) design the pseudo-rigid-body diagram, (2) transform it into the compliant mechanism (CM), (3) analyze the mechanical behaviors using FEM, (4) implement multi-objective optimization using NSGA-II with Pareto-optimal front, and (5) seek the global optimum solution by determining Entropy weight with TOPSIS method. Experiments and GA-PID feedback control are carried out to evaluate the performances of the mechanism. The discrepancies of the theoretical, and simulated results benchmarked against the experimental results for the displacement amplification, and natural frequency are 3.67%, and 1.73% respectively. With an integration of a dual parallelogram mechanism to the linear guide, both simulated and experimental results show that the parasitic motion is negligible. The closed-loop control error of the output displacement is smaller than 0.02 mu m. These results reconfirm the effectiveness of the proposed optimization method for other kinds of CMs.