Structural design and research of a novel lower limb rehabilitation robot for human-robot coupling

A bedside rehabilitation robot is developed to address the challenge of motor rehabilitation for patients with lower limb paralysis. Firstly, based on the principles of physical rehabilitation, a two-link planar robot model is used to simulate both the robot and human lower limbs, and the coupling characteristics between the human and robot are thoroughly analyzed. Then, the lower limb rehabilitation robot, fitted with an end-effector and ankle wearable feature, is designed according to the structural parameters. To enhance patient safety during rehabilitation, the device incorporates a freely rotating leg support mechanism that reduces the load on the ankle due to gravitational forces, and a two-stage series elastic mechanism is integrated below the foot support to provide a passive compliant output of robot power, allowing for more natural movement and reducing the risk of injury. Secondly, dynamic modeling is used to determine the dynamic parameters of the robot by conducting simulation calculations based on the inertia parameters of the human body and the robot model design parameters. Finally, an experimental platform is established using the structural and dynamic parameters, and the robot's reliability is validated through experimentation. Results indicate that the robot can accurately complete passive rehabilitation training tasks, and the dynamic parameters meet the expected requirements.