Robust Synthesis of Planar Function Mechanisms with Joint Clearance

The random factors in the mechanisms make the output of the motion fluctuate around the nominal value. The fluctuation leads to the reduction of movement precision and reliability of the mechanism. In order to reduce the sensitivity of mechanism motion output which effected by uncertainty and improve the quality of mechanism motion, we propose a robust synthesis approach which taking random factors such as links dimensional tolerances and joint clearances etc into account. First the hybrid dimensional reduction method (HDRM) was used to establish the probability model of mechanism motion error with clearances. Then the Taguchi quality loss function was introduced to derivate the quality loss function of motion of mechanism, and the robust design model of planar path mechanism was established. Finally, the synthesis of planar function mechanism was given to illustrate the effectiveness of the proposed method. Verification result shows that the new design method can improve the robustness of mechanical motion effectively which was proposed in the paper, the average mean and mean standard deviation of motion error of designed mechanism reduced by 55% and 25%, respectively, which were lower than original mechanisms'.