A novel shoulder-elbow exoskeleton with series elastic actuators

This work presents a new shoulder-elbow exoskeleton (NESM) for upper-limb neurological rehabilitation. The system has four active degrees of freedom, namely shoulder adduction/abduction, flexion/extension and intra/extra rotation and elbow flexion/extension, together with eight additional passive degrees of freedom for the alignment of the motor axes to the human joint axes, regardless the user's specific anthropometry sizes. All the four active joints employ series elastic actuators: such compliant architecture makes the device both controllable in position mode and in torque mode. In order to realize a safe human-machine interface in the rehabilitation treatment, an algorithm for detecting spastic user contractions, or equivalently collisions with external objects, based on the torque measured in real-Time by the device, has been preliminary tested.