Compensation of packet loss for a network-based rehabilitation system

In this paper, a network-based rehabilitation system is proposed to increase mobility of a rehabilitation system and to enable tele-rehabilitation. Control algorithms and rehabilitation strategies distributed at the central location (physical therapist) and the local site (patient) communicate over wireless network to realize a network-based rehabilitation system. To deal with possible packet losses over wireless network, a modified linear quadratic Gaussian (LQG) controller and a disturbance observer (DOB) are applied. The performance of the proposed system and control algorithms is verified by simulation and experiment with an actual knee rehabilitation system. The simulation and experiment results show that the network-based rehabilitation system with the proposed control schemes can generate the desired assistive torque accurately in presence of packet losses.