Body guidance syntheses of four-bar linkage systems employing a spring-connected block model

•A unified method to solve body guidance mechanism synthesis problems is proposed.•A spring-connected block model is employed to solve the synthesis problem.•An optimization problem is formulated using model parameters as design variables.•Four-bar linkage systems with revolute or sliding joints can be synthesized effectively.

The body guidance synthesis, the task of seeking a mechanism which simultaneously generates a desired path of a point fixed to a link and desired orientation variation of the link, is the most difficult problem in syntheses. In the present study, a unified synthesis method for simultaneously determining the type and dimension of a planar four-bar linkage system is proposed to solve body guidance synthesis problems. A spring-connected block model is employed and parameters of the model including block sizes, spring stiffness constants, spring directions, input joint location and coupler point location are employed as design variables to formulate an optimization problem. Solving the optimization problem yields a simultaneous solution for the type and dimension of a planar four-bar linkage system.