Experimental evaluation of an assistive knee brace with magnetorheological actuator

Magnetorheological (MR) fluid is a smart fluid, which theological behavior can be controlled by magnetic field. Rotary devices using MR fluids have the benefits of high torque, good controllability, and low power requirement. Recently, we developed a new MR actuator and applied it to assistive knee braces. It was demonstrated that the knee brace with this MR actuator can provide proper torque under control. In this study, we evaluate the knee brace with MR actuator on three aspects: power consumption, torque output performances, and safety. A knee brace with MR actuator is compared to the knee brace without MR actuator. The power consumption for both knee braces under bending and extending processes as well as normal walking are evaluated; the force/torque controllability and output inertia of knee brace are studied; and the safety under some extreme conditions is tested.