Research on an optimal method for designing planar four-bar mechanisms according to a predetermined trajectory

This paper researched on designing a planar four-bar mechanism to realize a predetermined trajectory in a better way. In order to reproduce a given trajectory accurately, the interior point penalty function method was used in this paper. First of all, mathematical model was established, the dimension of each link, location of the fixed hinge and angles between some links were taken as design variables. Secondly, the objective function is established. According to Grashof Criteria and the minimum value of the transmission angle, the constraints of the design were determined. The interior point penalty function method is used to find the optimal solution of the objective function. Thirdly, a program for working out the optimal solution was written in Matlab to make the optimization method available. Finally, a wheelchair design was taken as an example to verify the availability of the computer program.