Solution region synthesis method of planar one-dof six-bar linkages for specifying 4-positions of a 3R open chain

This paper addresses the synthesis problem of one-dof six-bar linkage motion generation for four precision points. A novel and convenient synthesis approach is introduced. With our method, a 3R chain that guides the movement of its end-effector through a set of four specified task positions is given. We then attach two RR links to this 3R chain to obtain a six-bar linkage. Motion generation can produce an infinite number of solutions for four desired positions. It is difficult for designers to synthesize defect-free linkages and synthesize the best linkage through rapidly and precisely selecting curve points that satisfy every design condition. To solve this problem, a solution region method is given in this paper. With this method an infinite number of mechanism solutions can be expressed on a coordinate plane. In addition, the paper still puts forward a distinguishing method for testing circuit and branch defects for Watt-I six-bar linkages. The feasible mechanism solution regions without any defects are obtained by using the solution region method.