High-Performance, Virtual Constraint Control of a Powered Prosthetic Leg

Powered prosthetic legs independently control different joints and time periods of the gait cycle, resulting in control parameters and switching rules that can be difficult to tune by clinicians. This challenge might be addressed by a unifying control model used by recent bipedal robots, in which virtual constraints define joint patterns as functions of a monotonic variable that continuously represents the gait cycle phase. Engineers at the University of Texas at Dallas have applied robot control theory to enable powered, robotic prosthetics to respond to the wearer's environment and help amputees walk. Transferal (above-the-knee) amputees at the Rehabilitation Institute of Chicago were able to move at speeds of more than 1 meter per second and exerted less energy than with their traditional prostheses.