MULTIOBJECTIVE OPTIMIZATION OF A LEG MECHANISM WITH VARIOUS SPRING CONFIGURATIONS FOR FORCE REDUCTION

In this paper, the design of a two degree-of-freedom leg mechanism is accomplished by a two-stage optimization process. In the first stage, leg dimensions are optimized with respect to three design objectives: minimize (i) peak crank torque for an entire walking cycle, (ii) leg s ize, and (iii) vertical actuating force. Following the optimization of leg dimensions, in the second stage, spring elements with various pla cement configurations are considered for further reduction of the actu ating force and crank torque. Several tradeoff solutions are obtained and a comparison between various spring configurations is made. It is shown that the inclusion of spring elements can significantly reduce t he actuating force and crank torque.