Model-Dependent Prosthesis Control with Real-Time Force Sensing

Lower-limb prosthesis wearers are more prone to fall than non-amputees. Powered prostheses can reduce this instability of passive prostheses. While shown to be more stable in practice, powered prostheses generally use model-independent control methods that lack formal guarantees of stability and rely on heuristic tuning. Recent work overcame one of the limitations of model-based prosthesis control by developing a class of stable prosthesis subsystem controllers independent of the human model, except for its interaction forces with the prosthesis. Our work realizes the first model-dependent prosthesis controller that uses in-the-loop on-board real-time force sensing at the interface between the human and prosthesis and at the ground, resulting in stable human-prosthesis walking and increasing the validity of our formal guarantees of stability. Experimental results demonstrate this controller using force sensors outperforms the controller when not using force sensors with better tracking performance and more consistent tracking performance across 4 types of terrain.