Implementing human-like motion patterns in a trans-humeral prosthesis of three degrees of freedom and parallel actuators

This work purposes an innovative methodology for implementing and executing patterns of natural motion from a healthy human arm in an upper limb prostheses using parallel actuators. Firstly, it was developed a calibration control capable of simultaneously gathering on-line the movement range of all actuators of prosthesis. Then, ten calibration tests were performed in which movement ranges were characterized and averaged into single values called "calibration ranges". Later, the kinematics approximation of two activities of daily living (ADLs), already available from a previous work, were physically execute trough the control system already implemented in the tested prosthesis. Finally, positioning error and standard deviation of ADLs executed are obtained. The results gathered from experimentation take us to two different conclusions: 1) It was possible to properly perform the two characterized ADLs (with an average “positioning error” below 1.5 %), and 2) As ADLs applied were analyzed and reproduced by prosthesis at the elbow joint level, it is necessary a trade-off movement of user to properly perform the desired actions.