Using ‘stall detection’ as an auxiliary mechanism for sensing obstacles and hand grasping in arm prosthesis

This paper proposes a novel method for sensing obstacles and hand grasping activities in electromechanical arm prosthesis. The described method is based on indirectly sensing `Stall´ condition in prosthesis actuators through hall-effect sensors already embedded on its dc motors, thus not requiring external sensors. To test the proposed methodology, an electromechanical arm prosthesis of 3 degrees of freedom (DOF), plus `open-close´ of hand, which is being developed at CINVESTAV Mexico, was used. At the end of this paper, experimental measurements performed on the tested prosthesis, using and non using `Stall Detection´, are shown. We demonstrated that methodology can be used successfully for “sensing obstacles”, but it cannot be used alone for “hand grasping”. In any case, this technique demonstrated to be a good method to simplify and strengthen control of prosthesis.