Study On Lower Limb Exoskeleton For Rehabilitation Based On Multi-source Information Fusion Including SEMG&Interactive Force And Its Clinical Trail

The patients with chronic diseases increase with elderly population. The conflictbetween limited medical resources and strong demand for quality medical servicesbecomes more and more serious. Furthermore, investigations indicate that a late orinappropriate treatment to the patients with nerve injury caused by diseases such as strokemay lead to hemiplegia or paralysis. Therefore a device that can provide sufficient activerehabilitation treatment is in dire need.In order to help the recovery of motor function after stroke by rehabilitationexoskeleton robot, the thesis conducted in-depth research in prediction of human motionintention, closed-loop control of the human-machine system, development and clinicaltrial of the rehabilitation exoskeleton system. The main contents and contributions of thethesis can be summarized as follows:In order to promote the application of the exoskeleton rehabilitation system in clinicaltreatment, active and passive rehabilitation is designed according to the Brunnstromstaging of patients with central nervous system injury, and progressive rehabilitationstrategy is proposed based on real-time monitoring and evaluation according to differentrequirements of the patients. However, there are three key points that should be solved:accurate prediction of motion intention in real time, coordinated control of thehuman-exoskeleton system, development of the lower extremity rehabilitation exoskeletonsystem and clinical rehabilitation.Aiming at accurate prediction of motion intention in real time, and in order to reducethe motion delay of exoskeleton system, differentiated method is used to extractinformation from sEMG in real time. Feature extraction experiments to the synthetic signals and sEMG indicate that AR model based differentiated method can extract theinformation50ms in advance and the accuracy is10%higher. Multi-source informationbased neuro-fuzzy network is established to predict human motion intention in real time.The performance of network with different topology structure is compared in theexperiments. The results indicate that the network with best structure can reduce the errorby about6.4%.Aiming at coordinated control of the human-exoskeleton system, a sEMG and EPPbased human-machine interface and coordinated control strategy are established.Coordinated control is realized based on a bidirectional human-machine interface, whichincludes a motion control interface and an information feedback interface. The motioncontrol interface control the exoskeleton by real-time prediction of human motionintention based on multi-source information fusion and kinematic and dynamic model ofthe exoskeleton. The information feedback interface detects the joint angle or torque inreal time and feed the information back to human body in the form of pressure of thegasbag. Experiments of coordinated control demonstrates that human-machine interfacecan help the wearer control the exoskeleton to desired angle, the errors are6.9780°,7.7946°and9.6750°when the desired angles are0°,30°and60°respectively.Aiming at development of the lower extremity rehabilitation exoskeleton system andclinical rehabilitation, the exoskeleton is developed based on the characters of human limb.The lower extremity exoskeleton includes two active degree of freedoms which is hip andknee, the range of motion is-25~60°and0~110°respectively. They are driven by a ballscrew and four-bar linkage. Weight-support devices with bed type, chair type and standingtype are developed to realize rehabilitation with different posture. The hardware includesthe sEMG amplifier with maximum amplification of5000times; the ISA based device forsEMG acquisition with16channels and maximum sampling frequency of30kHz; and theUSB based motion control card with four axes. The application is also developed for theexoskeleton robot and the device for sEMG acquisition. Preliminary clinical trials of thelower extremity exoskeleton system that conducted in the Shanghai6th People’s Hospitalindicates the rehabilitation system can help recovery of range of motion and muscle activecontraction in shorter time with better performance and less manpower consumption.