Compliant mechanisms are prone to generate unwanted parasitic motion in the input and output directions

which is detrimental to the drive and motion control of the mechanism. To solve this problem

a topology optimization method of compliant mechanisms considering parasitic motion is proposed in this paper. Based on the solid isotropic material with penalization (SIMP) method

the parasitic motion is introduced into the objective function

in which the rotational motion is represented by the translational displacement difference between two points. The performance relationship between output displacement and parasitic motion was considered as the objective function. Weight factor was used to convert the multi-objective into a single objective

the topology optimization model of the compliant mechanism was established. The Heaviside function was used for density filtration

and the optimization criterion (OC) method was used to solve the problem. Design of a compliant amplification mechanism with low parasitic motion at the input end was taken as an example

and the topology optimization results under three different conditions are given. Finite element analysis (FEA) of the optimized mechanism was performed using ANSYS Workbench

which verifies the validity of the proposed method.