Mechanical Study On The Force Of Upper Extremities During Assistive Walking Based On Simulation Of Knee Joint Stiffness

With the development of biomedical engineering and rehabilitation medicine, walking aids have been playing a more and more significant role in the reconstruction of the standing and walking function. So, the evaluation of the walking effect has been a hot problem which is needed to be investigated immediately. At present, there are few researches about the situation of the upper extremity force during the assistive walking which can provide a practical meaning for this research.The research of upper extremity force during the assistive walking includes two parts: the collection of the force data and the research of force mode. This thesis is based on a knee joint stiffness simulation experiment in which we utilize a special-designed walker dynamometer system which is designed by ourselves as the testing flat. Through a multi-channel strain gauge bridge network instrumented on the walker frame, we collect the HRV data of 15 healthy youths in four different stiffness modes. And in this research, a significant difference analysis of HRV characteristic parameters was carried out by using the statistical analysis method. The discussions and analysis were made about the effects exerted on upper extremities from different stiffness modes. On the basis of the statistical analysis, a SVM mode recognition investigation of different stiffness modes was made by using HRV as the eigenvector.The results of this research indicate that the knee joint stiffness will have a great influence on the situation of the upper extremity force during the assistive walking. It is also concluded that for the patients who have only one leg dysfunction, the knee joint stiffness has little impact on some vectors of HRV including the horizontal force on healthy side hand, the vertical force on healthy side hand and the vertical force on affected side hand. Through researches, we can conclude that the statistical analysis method and support vector machine (SVM) are effective tools in the research of differences of upper extremity force at different knee joint stiffness modes. And it is also founded that the non-linear kernel function SVM is more effective than the linear kernel function SVM in obtaining the non-linear information in HRV. And all the results above will be helpful to the evaluation of the effects of rehabilitation walking.