Design And Force Feedback Control Research Of SEA-based Hand Rehabilitation Exoskeleton Robot

Stroke is the leading cause of cardiovascular disease in China,with over 10 million people suffering from stroke at this stage,and the trend is increasing year by year.Patients with stroke have a severe loss of mobility and poor motor skills after surgery and are unable to complete rehabilitation on their own,requiring the combined assistance of the patient and their caregivers,therapists and physicians.The rehabilitation training process is extremely tiring and boring,requiring great effort from both the patient and the rehabilitation physician.The number of rehabilitation physicians in China is small and the number of patients is large,and the ratio of the population is only 4:1 million,which is far below the level of developed countries.Therefore,this paper proposes a research proposal for a hand rehabilitation exoskeleton robot that can replace the rehabilitation physician in the rehabilitation training of patients to address these two problems.Human hand anatomy,joint displacement forms,and spatial trajectories of human hand movements have been analyzed.The movements that can be performed by the hand are classified.The focus of the study was determined according to the importance of each hand movement.Performance indicators of the hand rehabilitation exoskeleton were studied.The study mainly includes finger movement space,finger movement angle,and exoskeleton assisted force.Research on the structure of various hand exoskeleton robots,analyze their advantages and disadvantages,and design hand exoskeleton configurations through research,improvement,and design.A rigid directdrive hand rehabilitation exoskeleton robot driven by five rotary motors and one linear motor was designed.Motor model is selected.Focusing on the mechanism analysis and kinematic modeling of the hand thumb CMC joint exoskeleton,we obtained the mapping relationship between the exoskeleton driven joint motion parameters and the force/moment applied to the thumb.Various SEA structures applied to exoskeleton robot joints have been analyzed.Based on the designed exoskeleton structure and transmission form,a new type of SEA transmission joint with small size and light weight and stable performance was designed,including linear SEA and rotary SEA.Torsion spring stiffness calculation model is analyzed and modeled.The forces and deformations as well as the static and dynamic stiffness and load carrying capacity of the SEA elastic element are analyzed.Torsion springs were processed by wire cutting process,and various torsion spring test benches were designed and fabricated.The static stiffness and dynamic stiffness of torsion springs were obtained through testing,and the stiffness calculation model was verified.Repeatability tests have shown that torsion springs maintain stable torque output and feedback after high frequency bi-directional loading and tens of thousands of cyclic movements.The bandwidth of both SEAs were analyzed separately,and the bandwidth of both rotational and linear SEAs met the bandwidth requirements of the hand rehabilitation exoskeleton.Robot flexible joint control method was briefly analyzed and introduced,and force feedback control was selected as the control method for SEA flexible joints.Build a position feedback test platform,combine simulink and d Space platform to implement position feedback,and verify the position feedback algorithm.Experimental platform of f/e and e/e motion force feedback for robotic exoskeleton was built to verify the reliability of force feedback for both motion modes of the exoskeleton robot.According to the experimental results,both force and position feedback effects can be achieved and the feedback effect is good.The force control experimental platform and control program are built to verify the effectiveness of the force-position feedback Jacobi matrix and the reliability of the PID force feedback control.Performance testing of hand rehabilitation exoskeleton robot and clinical trials and evaluations were completed.The motion angles of the knuckles were compared between worn and unworn states using the Opti Track motion capture system and the MYO surface electromyography signal collector.The kinematic transparency of the hand rehabilitation exoskeleton robot driving the rehabilitation movements of the patient’s hand was calculated by Pearson’s coefficient.Designed and built the XYZ coordinate motion platform to simulate the finger joint rotation center displacement,and demonstrated the self-alignment capability of the designed rehabilitation exoskeleton robot for different hand sizes and joint "variable axis motion".Virtual interactive game platform was built to achieve a fun rehabilitation process and enhance patients’ motivation for rehabilitation.Evaluated the interaction forces between the exoskeleton and the manual hand during rehabilitation.Designed and conducted fineassisted movement tests,as well as clinical trial evaluation and validation.