Topology optimization design of compliant amplification mechanisms with low parasitic displacement

Abstract

Compliant amplification mechanisms amplify input displacement in the desired output direction. However, owing to structural design, parasitic motion can easily be produced in an unexpected direction. The parasitic motion has a negative effect on the motion accuracy of the mechanism. To solve this problem, a topology optimization method for compliant amplification mechanisms with low parasitic displacement was proposed. Based on the variable density topology optimization method, the topology optimization model of the compliant amplification mechanism was established with the goal of increasing the output displacement and reducing the parasitic displacement. Volume ratio was set as constraint condition. The optimization criterion (OC) method were used to solve the problem and topology optimized amplification mechanisms were obtained. Simultaneously, the configuration characteristics and displacement amplification ratios of the mechanism under different virtual spring stiffnesses were compared. To verify the validity of the method, the performance of the topology optimized amplification mechanism and the typical amplification mechanism were compared using finite element simulation. The displacement amplification ratio is 5.95 and 3.17, and the relative parasitic displacement is 0.6% and 10.27%, respectively. Finally, the performance of the topology optimized amplification mechanism and the typical amplification mechanism was verified by experiments. The displacement amplification ratio is 5.72 and 3.06, and the relative parasitic displacement is 0.95% and 10.64%, respectively. Simulation and experimental results show that the topology optimized amplification mechanism has a larger displacement amplification ratio and a lower parasitic displacement, which verifies the validity of this method.

Nonlinear design, analysis, and testing of a single-stage compliant orthogonal displacement amplifier with a single input force for microgrippers

“…Compliant mechanisms that do not introduce clearance and friction issues are commonly used to construct displacement amplifiers, in which single-stage displacement amplifiers, e.g. the lever-type mechanism [11], triangulation-amplification-based mechanism [12,13], Scott-Russell amplifier [14], and topology-optimized amplifier [15], are more compact than the multistage ones [16,17].…”