A wearable robot for lower limb fracture reduction and rehabilitation: Design and experimental verification

Most current orthopedic robots focused on fracture reduction surgery with limited involvement in postoperative rehabilitation training. However, post-surgical orthopedic rehabilitation training directly impacts the recovery of mobility, ambulation, and limb function in patients. Here, we propose a six degree-of-freedom (DoF) parallel robot that can perform fracture reduction surgery as well as postoperative rehabilitation training for lower limb. The actuation system is switchable to reduce the weight in fixed status and reuse the actuation units for lowering treatment costs. An optimal parameter design based on multi-objective optimization is presented for maintaining lightweight and high stiffness. The wearable robot has a 1.7 kg weight in electric mode and 1.3 kg in manual mode, with >80 kg payload. A hierarchical control strategy with three control modes is developed to meet the requirements of different stages of fracture treatment. Our preliminary experiments on bone models demonstrated the potential effectiveness of the proposed wearable robot for lower limb fracture reduction and rehabilitation training.