Semi-active prostheses for low-power gait adaptation

Abstract Semi-active prostheses occupy the middle ground between traditional passive prostheses and powered robotic prostheses. Semi-active prostheses aim to improve biomechanical function by modulating their mechanical properties with minimal actuation, rather than directly powering the movement of the body. This paradigm requires a different approach to design, from conceptualization of how the prosthesis might be beneficial to mechanisms that can implement semi-active control of properties. This chapter presents an overview of the design process that enables these devices to be realized, including considerations for biomimetic devices in general and semi-active prostheses in particular. Key ideas for semi-active mechanisms are described including discussion of why they are important enablers of this technology. Examples are given from the author’s work, including details of the design process for prostheses that semi-actively control their shape, stiffness and alignment.