| Motor rehabilitation is crucial to paralyzed patients caused by spinal cord injury and stroke, which can enhance plastic recovery of the central nervous system. At present, advanced rehabilitation systems mainly include two kinds of technologies, i.e., functional electrical stimulation(FES) and robotic exoskeletons.Even though FES and robotic exoskeletons both have successful applications and even commercial products, some intrinsic drawbacks impede them from achieving satisfactory therapeutic effects in respective applications. Recently, hybrid rehabilitation devices that combine exoskeletons with FES have been one of the research hotspots in rehabilitation engineering.According to the practical requirements, the hybrid rehabilitation systems for lower extremities with one and two degrees of freedom are designed, which are based on synergetic control strategy. The performance of the hybrid systems is tested via simulation and experiments separately. The synergetic control scheme aims to regulate the torque allocation between exoskeletons and FES. The reference trajectories of FES and exoskeletons are generated by central pattern generator(CPG) and the synchrony can be achieved via regulating the phase difference. Besides, an experimental platform is built for hybrid FES-exoskeleton rehabilitation of knee joint, which uses a series elastic actuator to achieve stable torque control. Based on this platform, some proper experimental protocols have been designed, and evaluation experiments are conducted on both healthy subjects and paralyzed patients. The analysis of experimental data illustrates that the hybrid rehabilitation system of knee joint can balance the assistance torque between FES and the exoskeleton under the synergetic control strategy.The results of hybrid rehabilitation systems with one and two degrees of freedom through simulation and experiments demonstrate the feasibility and superiority, which will lay the foundation for further clinic implementation. |
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