Emulation of Ankle Function for Different Gaits through Active Foot Prosthesis: Actuation Concepts, Control and Experiments

Abstract

A main effort has been devoted in this thesis to consider the effects of the actuator components (i.e. springs, dampers and motors) and their configuration (i.e. the way they are assembled) in power and energy requirement of powered foot prostheses. It has been investigated which actuation mechanism would have the least requirements to perform a certain human gait (e.g. walking, running, ascending or descending the stairs). This thesis shows that the components of the robotic foot and their configurations are important design factors. This information is fundamental for building mechanical prototypes of active foot prostheses. In addition, the human body is equipped with muscle assemblies to actuate a joint. In robotics this phenomenon is called over-actuation. In this thesis, it was investigated if and how this fact could be used to reduce power-energy requirements in active foot prosthesis. Furthermore, the control structures of the active foot prostheses are investigated and discussed and the results of the first laboratory experiments with the Powered Ankle Knee Ortho-prosthesis (the PAKO platform) are explained. In continuation to this topic, some master controller schemes were introduced for gait identification. A video of experiments with PAKO platform can be seen here: https://www.youtube.com/watch?v=i7N3L6RsNNU