Design and Control of a SEA Driven Knee Exoskeleton for Walking Assistance

Hemiplegia is the most common sequelae of stroke, which will lead to the loss of mobility in patients. Rehabilitation robots can efficiently assist patients in performing rehabilitation training. This paper designed an exoskeleton based on a series elastic actuator (SEA) to assist patients with post-stroke hemiplegia for knee rehabilitation. Due to the use of SEA, the exoskeleton can achieve low impedance and precise force control. The mechanical limit can improve the safety of the device, and the bracket can reduce the wearing burden on the human body. Unlike traditional rigid drives, our design improves compliance of human-robot interaction. The spring can provide cushioning for increased safety when the patient suffers an accidental shock. In this paper, the design process is introduced and the exoskeleton model is analyzed. We implement the force control based on the integral separation PID algorithm and conduct experiments and analysis on the impact resistance of the exoskeleton.