Specific areas of research include foot prosthesis design, modeling of human walking, and walking robot design. We use simple passive-dynamics based models to gain insight into human walking. Our basic models have led naturally to some design ideas for building human foot prostheses that may help an amputee to walk more stably and with lower metabolic energy cost. We have also found that while sagittal motions can be inherently stable, lateral balance seems to require feedback control, most likely through foot placement. As new concepts like these arise, we build walking robots based on the proposed mechanical design or neuromuscular coordination strategy as a concrete proof of concept. Thus our understanding is advanced by simulation and experimentation with both humans and robots, with each approach benefitting from the others. See the links below for more details.