Design And Research Of M Humanmachine Compatible Upper Limb Rehabilitation Exoskeleton Based On Gravity Balance

Stroke is the brain tissue death caused by decreased cerebral blood flow or insufficient cerebral oxygen supply,which has become the primary cause of disability and death in China.High cost of rehabilitation nursing,low development level of rehabilitation medicine,excessive labor intensity of doctors,shortage of medical resources,and other issues promote the rapid increase of research and investment in the field of rehabilitation medicine.In order to improve the rehabilitation efficiency,relieve the resource shortage,and improve body comfort,many scientific research institutions have invested in the research and development of the upper limb rehabilitation robot,and achieved some research results through continuous efforts.Combined with ergonomics,and structure and motion characteristics of human upper limb,a compact and light upper limb rehabilitation exoskeleton is designed for 99% of Chinese adults over 40 years old in terms of human body size and range of daily life activities.On the basis of the overall scheme design,the structure design of 4-DOF training joints,2-DOF unpowered compensation joints and 1-DOF lifting platform are introduced in detail.Secondly,based on introduction of the gravity balance theory,the structural parameters of auxiliary springs and parallel links of the unpowered compensation joints are determined.The gravity balance model of exoskeleton system is established.An intuitive and quantitative spring adjustment scheme is proposed to adjust different human parameters,which makes the spring connection position linearly related to the body mass.The kinematic analysis of the compensation mechanism shows the applicability of the mechanism to 99% of the human physique,the range of motion of the humerus in daily life and different humeral elevation methods.The dynamic simulation study shows that the driving torques of the mechanism are reduced to the original 3% at most,which verifies the feasibility of the mechanism to provide stable support.For the exoskeleton training joints,the D-H method is used to establish its forward kinematics model,so as to establish the position and posture relationship between the wrist and the shoulder joint center.Based on Monte Carlo method,the wrist motion space is solved intuitively.The inverse kinematics solutions of the training joints are obtained by adaptive quantum genetic algorithm.The experimental results show that the stability and accuracy are improved by one order of magnitude compared with genetic algorithm.Finally,on the basis of the Lagrange equation method to deduce the dynamic equations of the training joints,the ADAMS software is used to carry out the dynamic simulation analysis of the limit positions of the exoskeleton joints.The intuitive driving torque curves are obtained,which provide the basis for the research of the control system.Finally,the hardware and software platform of exoskeleton control system is built,and three modules of control,perception,acquisition and execution are designed and debugged in detail.On this basis,the human-machine contact pressure collection experiments are carried out for different personnel.The results show that after enabling the compensation mechanism,the human-machine contact pressure of the test personnel is reduced by more than 70% compared with the case of losing the compensation mechanism.It is verified that the mechanism improves the human-machine compatibility and the robustness of different human bodies.