Research And Development Of A Five-DOF Active Upper Limbs Exoskeleton Force Trainer

During the rehabilitation process of stroke people,convalescent training plays an important role in patients' complete rehabilitation.Convalescent people can hold on their upper limb,but load movements is difficult.They have the certain initiative movement ability but still need training.Currently,there are few professional rehabilitation institutions,few therapists and few targeted rehabilitation equipment in the convalescent period,making it difficult for patients to go to the rehabilitation center regularly and do rehabilitation under the guidance of the therapists.Therefore,it's necessary to develop a Mechanical assisted rehabilitation equipment for convalescent patients and reduce their dependence on therapists.An active 5-DOF force trainer for upper limb was developed based on musculoskeletal system and mechanical design method,and experimental studies were conducted in this dissertation.The main work and achievements can be included as:1)Following the general rules of product development/design and users' requirement,the core design objectives were clarified through QFD.Based on the axiomatic design theory and the independence axiom,the functional requirements were comprehensively analyzed,the simplest engineering implementation scheme was sought,and the design objectives and order were clarified.According to the design objectives and order,a scheme design of the trainer structure was obtained.2)Taking into account upper limb musculoskeletal system and kinematics,detailed mechanical structure design was carried out,including the motion following mechanism,driving system and resistance loading system,so as to realize the movement following of the upper limbs of patients.The mechanical analysis of key load-bearing parts,kinematics analysis and motion simulation of the trainer(through CREO)were carried out,which theoretically proved the rationality of the trainer's design,structural reliability,measurement accuracy and movement feasibility.3)According to the needs of signal acquisition and feedback system,centralized control hardware system and client/local database schema software system were built.Individual joint motion data were acquired by a rotary encoder and were display by game images,using a sampling frequency higher than that perceived frequency of the human eye on the image,thereby achieved real-time tracking of the motion.A variety of training games were designed to meet meet the needs of patients' daily life activities.For different joints,a variety of training modes were set up in the training games,such as single-joint training mode and multi-joint horizontal compound training mode,so as to enhance the training performance of patients.By customizing the training duration and adjusting the spring resistance training level,the training difficulty was customized.At the end of the training,a training report was presented to therapists for improvement of the training program.A simple and easy-to-understand graphical operation interface is designed to make the operation simple,intuitive and convenient.4)The resistance training level and range provided by upper arm and forearm spring were calibrated,providing a direct and feasible quantitative data reference for training programs formulation.Repeatability experiments were carried out,and the tracking ability of the trainer was verified.The motion tracking ability and data acquisition ability were quantitatively evaluated by root mean square error(RMSE)and standard deviation(SD)respectively.Experimental results showed that the training device was capable of collecting the range of rotation of each joint.In the motion tracking experiment,RMSE was less than 2.5mm and SD was less than 2.34 mm.Hence,the 5-DOF force trainer designed in this dissertation realized the 5-DOF force training and motion control ability training of the upper limb,provided training programs with adjustable difficulty,established the information transmission closed loop among patients,therapists and the force trainer and provided a feasible way to motivate the patient training and assisted the therapists to update the treatment program.