Topology Synthesis and Optimal Design of an Adaptive Compliant Gripper to Maximize Output Displacement

This paper presents the optimal design process of an innovative adaptive compliant gripper (ACG) for fast handling of objects with size and shape variations. An efficient soft-add topology optimization algorithm is developed to synthesize the optimal topology of the ACG. Unlike traditional hard-kill and soft-kill methods, the elements are equivalent to be numerically added into the analysis domain through the proposed soft-add scheme. A size optimization method incorporating Augmented Lagrange Multiplier (ALM) method, Simplex method, and nonlinear finite element analysis with the objective to maximize geometric advantage (which is defined as the ratio of output displacement to input displacement) of the analyzed compliant mechanism is carried out to optimize the design. The dynamic performance and contact behavior of the ACG is analyzed by using explicit dynamic finite element analysis. Three designs are prototyped using silicon rubber material. Experimental tests are performed, and the results agree well with the simulation models. The outcomes of this study provide numerical methods for design and analysis of compliant mechanisms with better computational efficiency, as well as to develop an innovative adaptive compliant gripper for fast grasping of unknown objects.