On comparing two methods for low degree-of-freedom mechanisms

In this paper, we compare two our design methods for active mechanisms based on the motion analysis of given tasks. The common purpose of these methods is to achieve low degree-of-freedom (DOF) mechanisms. The mechanisms which are designed with two methods can reconstruct the approximated motions for the tasks that are defined by the motion trajectories of the end effectors. The difference of the methods is the independent variables to represent the approximated motion. There exists a tradeoff between the DOF and accuracy of the reconstructed motion trajectory. The proposed method optimizes the kinematic parameters of the low DOF mechanisms with respect to the evaluation index for the approximation error. The designed mechanisms achieve the high accuracy of the reconstructed motion trajectory. The kinematic parameters are determined by the numerical optimization method.