A variable structure pantograph mechanism for comprehensive upper extremity haptic movement training

Numerous haptic devices have been developed for neurorehabilitation of upper extremities, but their wide-spread use has been largely impeded for reasons of complexity and cost. In this paper we describe a variable structure pantograph mechanism that produces a versatile rehabilitation robot for movement training of the shoulder, elbow, and wrist. The device has three operational modes: ARM, REACH and WRIST. The performance of the mechanism, driven by series elastic actuators, is similar in all three operational modes while using a single control scheme and set of gains. This means a single device with minimal setup changes can be used to treat a variety of upper limb impairments following stroke, traumatic brain injury, or other direct trauma to the arm.