Coping with intrinsic constraints of neural origin in the design of rehabilitation robots: A preliminary study

This work proposes a mechatronic solution to increase the backdrivability of a rehabilitation robot in order to cope with intrinsic kinematic constraints which are adopted by the human brain to solve redundancy in motor tasks. In order to reduce the interaction force between the user and the robot and ensure the robot to follow subjects movements a pure force control algorithm has been adopted. The control law has been validated on the MIT-Manus robotic system: first simulation tests have been performed, and then experimental trials on the real machine have been realized in several operative conditions. A net decrease of human force required to execute a motor task in interaction with the robot has been verified both in simulation tests and experimental validation; this confirms that force control effectively reduce the robot perturbation to subjects intrinsic motor strategies. From these observations it would be possible to define useful indications for the design of a new generation of rehabilitative robots, which comply with constraints of neural origin.