Assistive controllers and modalities for robot-aided neurorehabilitation

Abstract Several studies have shown that exercise facilitates the recovery of motor functions following stroke. Intensity and frequency of practice are major determinants of this recovery, but mere repetitive task training results in only modest or no increases of motor function. The way robots can be used to facilitate training is of key importance for their application to therapy and has important implications for their mechanical and control design. Robots can be used for haptic rendering in virtual environments, to provide forces that facilitate task performance or task completion and to make a task more difficult and challenging. This chapter reviews the control strategies for robotic therapy devices and summarizes the techniques for implementing assistive strategies, including counterbalance techniques and adaptive controllers that modify control parameters based on the patient's ongoing performance.