In this paper, we present a virtual prototype for a Upper-Limb Rehabilitation Robotic System is review, where the conflict of stability for a non-linear system its implemented, using as a model a double inverted pendulum and its response in Matlab - SimMechanics. It demonstrates the ability and ease of using new computerized tools where simulation and modeling of a system becomes an important utility to understand control concepts and carry them out in a controlled environment, it also can be of great help ensuring the complete characterization of a system, in which it can also result in experimental results. A soft trajectory follower PID controller is implemented to provide individual rehabilitation movements in a 2 DoF robotic system.