Advanced cable robots for upper and lower limb rehabilitation

Since the mid-1990s, robotic systems for orthopedic and neurorehabilitation have been developed. Several studies and experiments have demonstrated that the use of robots, in conjunction with a physiatrist, leads to an improvement in the effectiveness of therapy, both in the short and long term. These devices primarily allow an increase in the duration and precision of delivered therapy. Additionally, they offer the possibility of activity recording, tele-rehabilitation, and multisensory stimulation of the patient through virtual environments. This Dissertation focuses on the design and implementation of two cable-driven rehabilitation robots for upper and lower limb rehabilitation. The design and control algorithm of a 5-degree-of-freedom robotic system, named MariBot, were improved to rehabilitate the upper limb of patients in the acute phase post-stroke. The control of MariBot involves a trajectory setup phase followed by the actual therapy where sliding control with forgetting factor technique is used to control cable motions and increase patient contribution. Initially, the physiatrist moves the patient's arm in space, constrained by the orthosis, setting a trajecory through waypoint and defining parameters for execution (velocity, repetitions, etc.). Subsequently, the machine cyclically guides the orthosis along a trajectory that interpolates the stored waypoints, applying assistance algorithms during the rehabilitation exercises. This work presents also the design and initial testing of a novel cable-driven device called AirStep that compensates for the weight of the legs, facilitating air stepping practice while supine. In the AirStep robot, kinematic and kientostatic analyses were conducted to optimize the parameters of the counterbalance system. Additionally, leg movement and its trajectory were experimentally validated through Motion Capture system and compared to trajectories typically performed during normal walking or running. A motor was incorporated to replace the manual assistance, successfully allowing stepping-like motions. Finally, a device for proprioceptive foot stimulation through vibrations was designed and implemented, and preliminary clinical tests were conducted on two individuals with incomplete spinal cord injury.