WalkMECH: design and control of an energy recycling transfemoral prosthesis

This study presents the design and realization of an energy-efficient trans-femoral prosthesis called WalkMECH. Trans-femoral amputees consume significant amount of extra metabolic energy (more than 65% extra) during walking compared to the able- bodied person. Therefore, we mainly focused on the design possibili- ties for reducing the metabolic cost of an amputee during walking. Both clinical and bio-mechanical research studies have shown that ... Finally, the adaptation of the prosthesis to the different walking speeds and gait characteristics of amputees is investigated by further exploiting the working principle. The realization of the third proto- type, WalkMECHadapt, together with the actuation system and con- troller architecture are presented. To keep the design both mechani- cally and metabolically energy-efficient, we design the actuation sys- tem based on the minimal actuation principle. With this regard, the system is designed to change the equilibrium position of the mov- able elastic element, that stores the energy during the swing phase of the gait, when there is no load on it. The system is evaluated with the experimental test set-up that enables a healthy subject walking with WalkMECHadapt. The test results show that the system is work- ing sufficiently for adapting the energy storage capacity of the Walk- MECHadapt thanks to the principle of the actuation system and the simple nature of the controller architecture. In conclusion, the evaluation studies on the performance and vali- dation of the working principle show that the prosthesis prototype is working as hypothesized. Also the feedback from the amputee partic- ipants are promising for the realization of WalkMECH as a prosthetic device. The patent application of the design was published under the Patent Cooperation Treaty (PCT) with the international publication number: WO 2012/177125 A1 on 27 December 2012.