Study On Dynamic Correction System For Shoulder Subluxation

Due to poor shoulder function and low strength in stroke patients,the incidence of shoulder subluxation(GHS)after stroke can be as high as 80%.If GHS is not corrected in time,the shoulder ligament will be fibrosis,eventually resulting in permanent disability of the upper limb.As the pathogenesis of GHS has not been clarified,no unified and effective treatment system has been developed.What is more,there are many risk factors and complications of GHS,which makes the rehabilitation of GHS require a systematic and long flow correction,including detecting the degree of GHS,maintaining the shoulder in a natural motion state,maintaining the shoulder stability,maintaining an appropriate compensation force,and improving shoulder function and muscle strength.Thus,it is difficult for patients and therapists to implement the whole correction task,and eventually results in poor rehabilitation of GHS.Considering the demands and challenges of GHS correction,this dissertation focuses on GHS long-term detection techniques,dynamic configuration design of GHS orthoses,gravity compensation monitoring and automatic adjustment mechanism,and physiological state monitoring of rehabilitation training,which could make GHS correction more scientific,effective,and safe.In order to achieve this goal,the dynamic correction system for GHS is proposed and investigated based on rehabilitation medicine theory and anatomy theory.The dynamic correction system for GHS mainly includes a detecting algorithm for the degree of GHS in terms of the flex sensor,a GHS orthosis configuration for omnidirectional shoulder motion and shoulder gravity compensation,an automatic compensation actuator for GHS orthosis based on shape memory alloy,and a detection algorithm for fatigue compensation based on surface electromyography.The main contribution of this dissertation can be summarized as follows:First,a GHS degree detection algorithm based on the flex sensor is proposed in terms of the shoulder physiological appearance change to solve the lack of an objective,safe,and wearable GHS degree detection method.On the strength of clinical experimental data,the relationship between the flex sensor detection result and the clearance of the glenohumeral joint is established to provide a data basis for maintaining the physiological integrity of the shoulder joint.In order to solve the problem of flex sensor sample anisotropy,a fast calibration method of the flex sensor is proposed,which makes the flex sensor easy to use in GHS detection.Second,an omnidirectional shoulder motion GHS orthosis configuration to compensate for arm weight is proposed to meet the demand of sufficient compensating force without resisting shoulder movement.The effectiveness of the omnidirectional shoulder motion GHS orthosis configuration is verified by theoretical mechanics calculation,experimental platform test,and prototype wearing test.This configuration meets the core technical requirements of increasing the glenohumeral joint’s stability and maintaining the shoulder in a natural motion state.Meanwhile,compared with the traditional GHS orthoses configuration,the proposed configuration can prevent the severe complications resulted by the shoulder motion restriction.Third,an automatic compensation actuator for GHS orthosis based on shape memory alloy is proposed to solve the problem that the shoulder easily falls into undercompensation.The shape memory alloy is used as the driving element to achieve the actuator integration,lightweight and low power consumption,making the actuator meet the requirements of wearable GHS orthoses.Through material mechanics calculation,structure design,and algorithm design,the defects of the small controllable range and nonlinearity of shape memory alloy are overcome,and the automatic and accurate adjustment of compensation force is realized.This actuator reduces the therapist’s work intensity and solves the problem of ineffective GHS orthoses.Forth,a fatigue compensation algorithm based on surface electromyography(s EMG)is proposed to solve the problem that patients are prone to a second injury caused by fatigue compensation during rehabilitation training.Through the experimental study of fatigue compensation in patients and healthy subjects,the characteristics of fatigue compensation relative to pathological compensation were clarified,and the relationship between the median frequency of SEMG signal and the degree of fatigue compensation was established.The fatigue compensation algorithm ensures the safety of GHS patients during rehabilitation training and guarantees the improvement of GHS patients’ shoulder function and strength.Finally,the dynamic correction system for GHS was used in the hospital for experimental study and clinical trial.The clinical trial of patients with GHS proves that the dynamic correction system of GHS meets the critically technical requirements,including detecting the GHS degree,maintaining the shoulder in a natural motion state,maintaining shoulder joint stability,and monitoring fatigue compensation state.The dynamic correction system for GHS fulfills the requirements of systematic and comprehensive correction of GHS.This dissertation synthesizes the techniques of flexible sensing,wearable design,shape memory alloy,and physiological electrical signal sensing,combines with the physiological structure of shoulder joints and the basic theory of rehabilitation medicine,develops the dynamic correction system for GHS.This system meets the core requirements in the GHS treatment,including long-term detection of the GHS degree,maintaining the shoulder stability and natural motion state,ensuring consistency of gravity compensation,and safely improving shoulder function,which provides a solid guarantee for effective and rapid rehabilitation of GHS.