Novel Physical Human-Robot Interactions at the Hands Alter Walking Coordination Without Relying on Mechanical Effects: 2024 10th IEEE RAS/EMBS International Conference for Biomedical Robotics and Biomechatronics (BioRob)

While current physical human-robot interactions (pHRI) aid walking primarily through direct mechanical effects, we take a different approach to altering gait through low-force interactions at the hands. We use our recently developed high-fidelity robotic testbed, Slidey, to examine pHRI at the hands consisting of velocity profiles with transient pulses. We hypothesize that our novel pHRI controller induces people to alter their gait coordination, which must be adapted for different contexts and is affected in gait impairments. Our study is the first to demonstrate that low-force hand interactions can elicit intended changes to gait coordination, with the ratio of step length to step frequency changing by ∼ 60% across experiment conditions. These changes were achieved with hand force amplitudes < 10 N and mechanical power transfer at the hands lower than levels required to directly alter gait. Our hand pHRI controller for altering gait opens many new areas of research with potential applications for gait rehabilitation and improving performance of human-robot collaborative tasks.