The exoskeleton for gait rehabilitation ALICE: dynamic analysis and control system evaluation using Hamilton quaternions

A robotic exoskeleton is an electromechanical device that can be worn by a person to increase its physical capacity, to assist locomotion or for gait rehabilitation processes. In the case of rehabilitation exoskeletons, the control system is required to be smooth and capable to match accurately with the patients' evolution in order to optimize the efficiency of their recovery, this implies the design of robust and precise controllers. In this paper, kinematic analysis, dynamic analysis and control system evaluation for ALICE rehabilitation exoskeleton is presented. Among the control techniques used are: the PD controller, adaptive PD, and the sliding mode controller. In addition, a stability analysis using the Lyapunov criterion is performed. To test the performance of the controllers, gait data obtained by the ONCE School of Physiotherapy in Madrid, which correspond to healthy people and people with multiple sclerosis, are used. MATLAB as simulation software and programming language is used.