Modeling and control of 4-DOF powered upper limb exoskeleton

The exoskeleton robots because of its potential applications in rehabilitation engineering, assistive robotics, and power augmentation are getting more attention in the field of robotics. Besides kinematics model and dynamic model, three type controllers are applied in position control mode, PID control, computed torque control and time delay control, respectively. For the sake of the difficulty in tuning the PID parameters and compensating the uncertainties of the dynamic model used in the computed torque control, time delay control is employed to reduce or cancel the effect of the uncertainties and is characterized by relatively simple gain selection procedure simultaneously. Simulation results show the feasibility of the proposed exoskeleton in supplement or reinforce the wearer's muscular strength.