Powered Prosthesis Locomotion on Varying Terrains: Model-Dependent Control with Real-Time Force Sensing
This addresses the risk of falling for prosthesis wearers by providing formal stability guarantees, though it is incremental as it builds on prior model-based controllers.
The paper tackled the problem of instability in lower-limb powered prostheses by developing a model-dependent knee controller that uses real-time force sensing at the human-prosthesis interface and ground, resulting in improved tracking across 4 terrain types.
Lower-limb prosthesis wearers are more prone to falling 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 provably stable prosthesis controllers that only require the human interaction forces with the prosthesis, yet these controllers have not been realized with sensing of these forces in the control loop. Our work realizes the first model-dependent prosthesis knee controller that uses in-the-loop on-board real-time force sensing at the interface between the human and prosthesis and at the ground. The result is an optimization-based control methodology that formally guarantees stability while enabling human-prosthesis walking on a variety of terrain types. Experimental results demonstrate this force-based controller outperforms similar controllers not using force sensors, improving tracking across 4 terrain types.