Dynamic Modeling and Identification of Wearable Lower Limb Rehabilitation Exoskeleton Robots

Abstract

Wearable lower limb rehabilitation exoskeleton robots play a positive role in lower limb rehabilitation training and assistance walking for patients with lower limb disorders. Firstly, the 3 degrees of freedom link-based dynamic model with friction is established by the Lagrange method. Secondly, a parameter identification experiment is designed based on a lower limb exoskeleton prototype. It contains three parts: static experiment of discrete controlled by specified position, dynamic experiment of uniform speed motion controlled by linear excitations, and dynamic experiment of continuous motion controlled by sinusoidal excitations. During the process of experiment, several terms in joint output torque expression are set to zero for simplicity of calculation, and leave the parameters to be identified. Furthermore, based on the acquired actuator torque data, nine parameters are identified by plotting and curves fitting with the least square method, including inertial parameters, static friction and Coulomb viscous friction. Finally, the parameter identification results are verified through comparing the torque measured by experiment and estimated by model.