Research On The Bed-type Gait Rehabilitation Trining System Based On Motion Coupling

The number of patients with lower limb dyskinesia caused by cerebrovascular disease and spinal cord injury is very large.The basic theory of rehabilitation medicine shows that repetitive rehabilitation training exercises can promote the remodeling of human nervous system and contribute to the recovery of human motor function.Professional rehabilitation robots can accelerate the process and improve the effectiveness of rehabilitation treatment.Bed-type rehabilitation robots with few drivers such as Erigo from Switzerland,are relatively low-cost,but they can only perform simple stepping exercises and cannot accurately simulate the gait of normal people.In contrast,some exoskeleton rehabilitation robots,such as Lokomat,can accurately simulate the gait of normal people.Each motion joint is driven separately,but the number of motors used is large,resulting in high cost and poor economy.The control is more complicated.Aiming at the existing problems of rehabilitation robots,a bed-type gait rehabilitation training system based on motion coupling was proposed.The modular design was adopted in order to reduce the cost of machining and maintenance and improve the convenience of use.The movement of each part is driven by a common motor.Cam-linkage mechanism was used on the leg movement module to generate accurate joint motion curves.The tilt of the bed can be adjusted to fill the demand of every stage of rehabilitation.Main contents are as follows:(1)The physiological structure of human lower limbs were introduced.The basic parameters of lower limbs were understood.Which laid a foundation for the determination of structural parameters of the rehabilitation training system.The kinematic coupling relationship among the hip,knee and ankle joints was analyzed.The results showed that the Angle of walking gait of the knee joint and ankle joint could be uniquely determined by the Angle and angular velocity of the hip joint.The coupling relationship between the motion of the joints and the motion of the thigh,calf and foot was analyzed.The results showed that the position of any point of thigh,calf and foot could be uniquely determined by hip joint Angle and angular velocity.The coupling relationship will provide a theoretical basis for the design of the rehabilitation training system.(2)The whole configuration of the rehabilitation training system of bed gait was analyzed,and the whole composition of the rehabilitation training system of bed gait was determined.That is,it was composed of the bed body with adjustable inclination and the gait training mechanism.The gait training mechanism included the leg motion auxiliary mechanism and the foot support mechanism.Based on the results of the second chapter of joint motion coupling of walking gait,the design scheme of the gait training mechanism was developed,.That is,the thigh part and the calf part respectively adopted the cam-linkage mechanism with similar structure to realize the periodic movement of the thigh and the calf.The normal walking gait was realized by the coupling movement of the leg motion auxiliary mechanism and the foot support mechanism.The man-machine coupling model of leg motion auxiliary mechanism was established.The connection between the leg and calf motion and the movement of the mechanism was discussed.Then the structural parameters of the plantar support mechanism were designed based on the coupling relationship between foot motion and the Angle of hip,knee and ankle joints.Based on the requirements of use,the design scheme of the bed configuration was proposed,the kinematics model of the bed was established,and the movement and stress analysis were carried out,which provided guidance for the bed structure design.Finally,the transmission ratio of each mechanism is calculated according to the movement coupling law of normal people walking.(3)Based on the adaptability of the leg motion auxiliary mechanism to patients of different heights and weights,the dynamic simulation of the leg motion auxiliary mechanism was carried out,and the total maximum driving torque required for the normal movement of the leg motion auxiliary mechanism was 62Nm,which provided a reference for the design and selection of the drive system.In order to evaluate the adaptability of institutions to individual patient differences,an evaluation method was proposed.The structural parameters of the leg motion auxiliary mechanism were optimized using lsqcurvefit function of MATLAB.The optimal values of a group of mechanism parameters were determined.(4)The mechanical body and sensor system of the bed-type gait rehabilitation training system were built.Debugging tests were carried out.Then the manned rehabilitation training experiment was carried out under the condition that the system was in good condition.The experimental results show that the maximum error of hip between the experimental angle obtained by the experiment in different states and the standard angle is less than 5.5°,the maximum error of knee is less than 6.7°.Which demonstrated the rehabilitation training system can simulate the walking gait of normal people well under different tilt states,and it is feasible to carry out rehabilitation training with this system.