An optimal method to determine the parameters of anthropomorphic finger based on four-link mechanism

Anthropomorphic fingers based on four-link mechanisms are commonly used in the design of the dexterous robotic hands. The most critical part of the design is to determine a set of optimal linkage parameters that will provide the desired mechanical configuration and motion scope to match human fingerspsila. The existing optimization method is based on the vector kinematics equations of the linkages, which must apply the abstract constraints to ensure that the four-link mechanism is crossed. These constraints are non-intuitive to apply and may yield unsatisfactory results if applied improperly. This paper will propose an alternative approach, a geometry-based kinematics, to ensure the crossed four-link configuration without applying the abstract constraints. This paper will briefly review the vector kinematics based optimal method. Optimization using geometry-based kinematics will be introduced. Constraints and boundary conditions for the optimal parameters of the four-link mechanism will be discussed. An example is given to demonstrate the effectiveness of the proposed method to an anthropomorphic finger.