Design and Control of an Active Humanoid Leg for Testing Lower-Limb Prostheses

The present paper deals with the development of a bench for testing different types of lower limb prostheses. Aim of the bench is to test the prosthetic devices considering working conditions as much as possible similar to the real ones with respect to methodologies provided by International Standards. These standards merely identify structural tests whose purpose is just to verify that the prosthesis, or their individual components, are able to ensure adequate strength properties during their use. The only functional test concern just the ankle-foot units. Test methods for the assessment of the functional performances of the whole prostheses are missing. There are no criterions for such tests and no benches. From this the need to build new test machines that, simulating both the stance and the swing phase according to sought gait standards, allow to assess the functional properties of different lower limb prostheses and to make comparison between them. According to this, the purpose of the present work is to assess the feasibility of such a bench, evaluating, by mean of a co-simulation executed considering a Multi-Body model of the bench developed using MSC ADAMS and a model of the control system developed using MATLAB/Simulink, its capability in guaranteeing the sequential replication of movements and loads that distinguish a leg during the execution of the stride. The obtained results demonstrate the feasibility of the machine, encouraging therefore the development of more refined models, considering technological solutions closer to reality.