Optimization design for linkage mechanism based on reliability of kinematic accuracy

In this paper, the optimization design of four-bar mechanism of mechanical finger is investigated by taking into consideration the motional smoothness and reliability of kinematic accuracy. In the investigation, first, the motion relationship between driving lever and driven lever is obtained by building a mathematic model for linkage mechanism of finger and the motional smoothness of mechanism can be described by the acceleration of driven lever. Next, the reliability index is obtained by first-order second-moment method and is used to reflect the reliability of kinematic accuracy. Then, the minimum acceleration of driven lever and the maximum reliability are respectively chosen as the objective function to establish the optimization model of the four-bar mechanism, with a certain boundary condition according to the practical requirement of finger. Last, the optimization design is completed by genetic algorithms (GA) and the simulation of optimization result is conducted with MATLAB. The results show that, as compared with the optimization design only considering kinematics, the proposed method is more reliable in kinematic accuracy of the finger.