Design and Simulation of a Mechanism for Human Leg Motion Assistance

Abstract

Legs are the mostimportant elements for accomplishing human physical work includingtransportation or displacement. In this paper, a new mechanism for human legmotion assistance has been proposed for rehabilitation purposes. The structureof human leg and its motions have been used as inspiration for design purposes.For a simple control algorithm, the proposed mechanism for the legs mustgenerate an ovoid path of the foot, by uniform rotating of actuating crank. Themechanism must generate an approximately linear trajectory of foot duringpropulsion. The resulting linkage is a single degree-of-freedom (DOF)mechanism, which exemplifies the shape and movement of a human leg. Theactuator of the mechanism is located in the upper portion of the linkagesimilar to it in a human leg. The mechanism is simulated and tested to verifythe proposed synthesis. A 3D model of the proposed system has been elaboratedin Solid Works®, booth for design and simulation purposes. Simulation resultsshow that the proposed mechanism performs movements similar to those of a humanleg. Maple and Adams software packages are used to simulate and validate the usabilityof the mechanism. The proposed mechanism demonstrates that a one DOF closedloop mechanical linkage can be designed to the shape and movement of the bipedhuman walking apparatus. The proposed mechanism is suitable for the fabricationof legged robots. Proportions of the linkage are estimated utilizinganthropometric measures of the human leg.