Flatness-based trajectory tracking control of a rehabilitation robot with disturbance compensation

Rehabilitation robots are an effective supplement to classical locomotion therapy, guaranteeing a high training intensity with a sufficient amount of iterations. Rehabilitation robots are developed with respect to the needs of the patients, ensuring safety and optimal training conditions. In this contribution, a control structure for a gait trainer is presented allowing unsupervised training. The controller comprises a flatness-based trajectory tracking control and a disturbance compensation. It is shown that the controller maintains an absolutely robust and, therefore, safe behavior for all kinds of disturbances, even for spasticities of the patient. Furthermore, the controller shows an elastic tracking behavior leaving space for the idiosyncrasies of the patient´s gait, while granting the qualitative characteristics of the gait trajectories at all times.