Research On Seven-DOF Upper Limb Exoskeleton Robot Based On Semg Signal Control

With the increasing aging in China and the onset of cardiovascular and cerebrovascular diseases at a younger age,the number of people with sports difficulties or incapacitated physical infirmity is increasing.For weak people assisted living in the present stage is mainly by artificial auxiliary product realization or the traditional sports,and the auxiliary pattern from cost and resources to the patient's quality of life are hard to meet the needs of society.At the same time,medical clinical evidence shows that the rehabilitation training for the frail people is very helpful to the recovery of their athletic ability.Exoskeleton,as a kind of wearable devices,with flexible movement,feature-rich,rehabilitation treatment and auxiliary combined with the advantages of life,become the future weak crowd life auxiliary equipment of optimal choice.However,the existing exoskeletons of upper limbs have such defects as high cost,heavy weight,poor recognition of motion intention and poor wearing comfort.Therefore,based on the 6-DOF exoskeleton platform developed by the research group,a 7-DOF exoskeleton robot was developed.At the same time,the calculation algorithm between sEMG signal and joint Angle and the exoskeleton control algorithm which can compensate the hysteretic phenomenon of lasso drive are studied.In order to solve the above problems,the proportional electromyogram control algorithm for the upper limb exoskeleton is realized by combining the two algorithms.With 7-DOF arm exoskeletons need to wear,so this topic first on human upper limb kinematical analysis,and the existing 6-DOF arm exoskeleton system were tested and analyzed.According to the analysis results,the design scheme of 7-DOF upper limb exoskeleton was developed.In this stud y,the exoskeleton is designed with lasso drive,which makes the motor layout more flexible.Thanks to the lasso transmission scheme,the overall weight of the exoskeleton is 3.5kg,which is lighter than the existing exoskeleton of the upper limbs.In the system,a large arm rotatory internal/external rotatory joint is added.The addition of this degree of freedom solves the problem of motion limitation and low flexibility caused by the lack of freedom in the original scheme.At the same time,in order to solve the hysteretic phenomenon caused by the lasso drive system,a multi-stage wire rope tensioning system was added to the exoskeleton of the upper extremity.The system consists of three kinds of tensioning devices,which are respectively applicable to differ ent installation positions and tensioning requirements of the exoskeleton.In addition,absolute encoder is designed in each joint to measure the actual motion Angle of each joint.After the completion of the design,the kinematics analysis of the 7-DOF exoskeleton of the upper limb was also carried out.There are two modes of use in the design of the exoskeleton of the upper extremity studied in this study,namely the active mode of the exoskeleton driving the wearer's movement and the passive mode of the wearer controlling the movement of the exoskeleton.In order to identify the wearer's motion intention more accurately and quickly,a set of sEMG acquisition,processing and operation mechanism is designed in this paper.In this paper,five main characteristic signals in sEMG signal are extracted as input values of the algorithm and the calculation method of sEMG-joint motion Angle is proposed by using random forest algorithm.The application of five machine learning algorithms in the calculation of sEMG-joint motion Angle is studied.Finally in order to verify this topic the research and development of upper limb exoskeleton structure and the performance of the control algorithm of physical movement experiment was carried out,respectively was carried out to r epresent the exoskeletons of two kinds of usage patterns three experiments: exoskeleton active mode control experiment,electromyographic signal control experiment in vitro,and electromyographic signal control dressing experiment.The experimental results show that the studied exoskeleton structure and algorithm can achieve the targets of rehabilitation training and sports assistance for the frail population,and the performance is better.