Articulated mechanism design with a degree of freedom constraint

This paper deals with design of articulated mechanism using a truss-based ground-structure representation. The proposed method can accommodate extremely large displacement by considering geometric non-linearity. In addition, it can also control the mechanical degrees of freedom (DOF) of the resultant mechanism by using a DOF equation based on Maxwell’s rule. The optimization is based on a relaxed formulation of an original integer problem and also involves developments directed at handling the redundancy inherent in the ground-structure representation. One planar test example is selected as the basis for the developments so as to compare the proposed method with other alternative approaches including a graph-theoretical enumeration approach which guarantees the identification of the globally optimal solution. Also, an inverter problem is treated where a continuation method is required in order to direct the optimization algorithm towards an integer solution.