Trajectory tracking control of a biomimetic exoskeleton for robotic rehabilitation

The main impetus for the development of bioinspired robotic technologies stems from their applications to some tasks which require a safe interaction with human beings, e.g., during rehabilitation exercises. In this context, this work presents the mechatronic design and the tracking control of a robotic exoskeleton actuated by biomimetic and soft actuators. The exoskeleton can perform some tasks of physical rehabilitation, whereas the intrinsic and tunable compliance of the robot joints guarantees the safety specifications required for human-robot interactions. The steps of design and realization described in this paper involve the synthesis and the implementation of a trajectory tracking controller. A nonlinear control law, which compensates for the nonlinear dynamics of the actuators, is employed in combination with a PID control action. The designed control law, experimentally validated during some sessions of robotic rehabilitation, achieves the robust regulation of the tracking error to zero.