A Comparison of a Passive and Variable-Damping Controlled Leg Prosthesis in a Simulated Environment

Abstract

This paper presents two control methods for a leg prosthesis: a passive based and a variable-damping based. First, the concept of the mechanical design for the leg prosthesis is described. A simulated environment is used to compare the two control methods. The joint setup and its control scheme, in which a passive or a variable-damping control can be easily implemented, are introduced for the prosthetic leg in the simulated environment. Intelligent prosthesis require a specific adjustment for each gait phase based on kinematic events of knee and ankle joints along a gait cycle. A feasible damping profile is generated based on kinematic and dynamical data of the knee joint along a gait cycle. This data set was extracted from a simulated biped which is 1.8 m in height and 76 kg in weight with 21 degrees of freedom during normal walking. The data show that the damping profile is critical between the toe-off and heel contact events. Tests using the simulated biped with the passive and the variabledamping controlled leg prosthesis during walking enables the comparison of both control approaches.