The number of mechanical degrees of freedom (DoFs) within rehabilitation robots directly influences the scope of the movements that a subject can perform when training walking. Currently, gait rehabilitation robots have a limited number of mechanical DoFs, as a consequence this limits the movements these robots can make possible. In this paper, the novel gait rehabilitation system CORBYS is presented which consists of the mobile platform and a powered orthosis which is attached to the platform. The CORBYS powered orthosis has 16 DoFs enabling more physiological movements, making it a state-of-the-art gait rehabilitation robotic system. With the sufficient number of DoFs to enable natural-like walking, the CORBYS robotic system enables the integration of the “learning gait by therapist demonstration” paradigm. This paper presents the fully integrated functional CORBYS gait rehabilitation system, with the focus on the implementation aspects which enable generation of the reference gait trajectory through learning by therapist demonstration, and the use of the generated trajectory in the robotic therapy session. The results of the initial evaluation of the robotic system obtained in tests with a selected patient are given in the paper.

This paper discusses two ways to estimate the interaction force at the end-effector of a robot. The first approach that is presented combines filtered dynamic equations with a recursive least squares estimation algorithm to provide a smoothened force signal, which is useful in the (common) case of noisy torque measurements. The second approach, which uses a generalized momentum based disturbance observer, is mainly discussed to compare it to the first approach. Although very different in appearance, it is shown that a close connection exists between both approaches. Simulation results for both algorithms are shown, and experimental results derived from a sensorless admittance controller that was implemented using the algorithms are presented.