Research progress of ankle-foot rehabilitation robots

With the development of medical-engineering integration technology and the growing clinical rehabilitation demands, intelligent rehabilitation robots have emerged as a prominent area of research in stroke rehabilitation. The application of exoskeleton rehabilitation robots holds significant potential to alleviate the pressure on rehabilitation resources in China. These robots offer high-intensity, high-repetition rehabilitation training for stroke patients, helping to restore limb motor function, improve daily living independence, and contribute to neuroplasticity. As such, they are becoming an essential treatment modality for patients with motor function disorders. In this review, we first categorize ankle-foot rehabilitation robots based on the interaction methods between the robot and the user, detailing their structural characteristics and application scenarios. Additionally, we classify existing control strategies, including admittance control, impedance control, electromyography control, trajectory tracking control, and Proportional-Integral-Derivative control, based on the rehabilitation needs at various stages of recovery. Each control method is summarized, and their current research status is analyzed. Besides, current research status of key technologies in rehabilitation robots, both domestically and internationally are also summarized in this paper. Finally, the key challenges in the development of ankle-foot rehabilitation robots and future research directions are discussed, providing a reference for the research and design of these robots.