The objective of this study is to focus on the feasibility of a robotic solution for rehabilitation of children with Cerebral Palsy (CP). For this purpose, to restore the walking abilities and in order to stimulate the brain functionality, two rehabilitation techniques have been compared (a conventional rehabilitation and a robotized one). Results indicate that the key of a performant exoskeleton with a good tracking of the gait cycle is to use robust controllers to guarantee the tracking even with kids' parameter variations. A PD controller and a sliding mode controller are implemented and compared in order to prove the difference of their robustness. Through the proposed solution, it has been shown that sliding mode control is more robust than PD controller.