This paper is aimed toward the development and evaluation of a novel active ankle foot orthosis (AAFO) based on shape memory alloy (SMA) actuators. This device intends to fill the gap in the existing research aimed at helping patients with drop foot muscle deficiencies as well as rehabilitation activities. To check the feasibility of this idea, a brief study is done on the dynamic behavior of ankle joint and then an SMA manipulator with a similar biological concept is used for experiment. Nonlinear behavior of SMA wires requires nonlinear control techniques such as Sliding Mode Controller (SMC) for tracking the desired ankle angle. Simulation results of three different techniques are compared (PID, SMC and SMC-PID) and finally the experimental result of a SMC-PID switching control is provided. This results shows that a switching control between simple PID and Sliding Mode Control can be a good alternative to follow the desired trajectory in slow walking cycles.

This content is only available via PDF.
You do not currently have access to this content.