基于PVDF的膝关节控制肌群运动信息采集研究

发布时间：2018-10-12 15:32

【摘要】：膝关节对人体来说至关重要,因为它的结构和功能相当复杂,且是人体最大的滑车关节。在日常生活、工作、劳动,尤其是体育运动中,膝关节都起着非常重要的作用。在球类、田径等体育项目中,姿势不当、重心不稳、负荷过重、准备运动不足以及下肢肌群疲劳等原因经常引发膝关节损伤继而引发下肢功能障碍甚至下肢瘫痪；膝关节周围的控制肌群决定了膝关节的安全,因此研究膝关节的控制肌群将对康复医学、病理诊断、运动科学和体育教学等领域产生深远的影响,对预防膝关节劳损和病变有着直接的意义。要研究膝关节的控制肌群,就需要在运动过程中采集肌群的运动信息。基于肌电信号的采集和分析只能够在某种程度上描述神经肌肉的运动。尽管相对于利用针电极通过刺入肌肉体接触肌纤维而得到肌电信号,表面肌电信号的采集使用面电极,具有无创伤性和无副作用等改善,但无论是肌电信号还是表面肌电信号都很容易受到人体自身导电性、心电信号、体温变化和个体体质差异等因素的影响,再加上肌电信号本身非常微弱并且频谱分布很窄,信息采集往往缺乏可靠性和一致性,并且采集过程需要昂贵的设备和安静的环境,难以在真实的运动过程中进行采集和监测。针对目前采集肌群信息的研究局限于肌电信号和表面肌电信号的现状,本文提出了一种新的采集方法：在运动过程全方位采集膝关节控制肌群的压电信息,准确获取肌群的力学运动学参数,以定量揭示膝关节控制肌群的生物力学特征和动力学规律。本文专门设计并制作了基于PVDF的膝关节控制肌群电信息采集传感器。PVDF压电薄膜具有质轻、柔软、极薄、耐冲击和抗腐蚀等优点,并且特别适合工作于动态环境。经过测试和仿真的对比,传感器的悬臂梁最终采用了圆形简支悬臂梁结构。针对传感器的性能开发了信号调理电路,并测试了传感器的性能：压力信号在500N-1500N之间,传感器有良好的输出；激励频率控制在750Hz左右,将获得偏差最小的传感器响应频率；激励频率低于6Hz或者高于2000Hz,传感器响应频率的偏差将超过5%。研究膝关节临床解剖学,设计了传感器阵列布置方案并利用运动紧身裤进行加工。利用深蹲运动进行了动态测试,证明了该采集方法经济、可靠、实用,能够有效采集和监测人体运动时膝关节控制肌群的电信息。
[Abstract]:Knee joint is very important for human body because its structure and function is very complex and it is the largest pulley joint. In daily life, work, labor, especially in sports, knee joint plays a very important role. In ball games, track and field and other sports events, the posture is improper, the center of gravity is unstable, the load is overweight, the preparation movement is insufficient and the lower extremity muscle group fatigue and so on the reason and so on often causes the knee joint injury and then causes the lower extremity dysfunction and even the lower extremity paralysis; The controlled muscles around the knee joint determine the safety of the knee joint. Therefore, the study of the controlled muscle group of the knee joint will have a profound impact on the fields of rehabilitation medicine, pathological diagnosis, sports science and physical education, etc. It is of direct significance to prevent knee joint strain and disease. In order to study the controlling muscle group of knee joint, it is necessary to collect the movement information of the muscle group during exercise. The collection and analysis based on EMG signal can only describe the neuromuscular movement to some extent. Although EMG signals are obtained by pricking the muscle body into the muscle fibers with needle electrodes, the surface electrodes used to collect surface EMG signals have improved in terms of non-traumatic and non-side effects, etc. However, both EMG signals and surface EMG signals are easily affected by the human body's own electrical conductivity, ECG signals, body temperature changes and individual physical differences. Besides, the EMG signals themselves are very weak and the spectrum distribution is very narrow. Information collection is often lack of reliability and consistency, and the acquisition process requires expensive equipment and quiet environment, so it is difficult to collect and monitor in real motion process. In view of the fact that the current research of collecting muscle group information is limited to the current situation of EMG signal and surface EMG signal, a new method is proposed in this paper: to collect the piezoelectric information of knee joint control muscle group in all directions during the motion process. The mechanical kinematics parameters of the muscle group were obtained accurately to reveal the biomechanical characteristics and dynamics of the knee joint controlled muscle group quantitatively. In this paper, the electrical information acquisition sensor of knee joint control muscle group based on PVDF is designed and fabricated. The PVDF piezoelectric film has the advantages of light weight, soft, extremely thin, impact and corrosion resistance, and is especially suitable for working in dynamic environment. Through the comparison of test and simulation, the cantilever beam of the sensor is finally adopted circular simply supported cantilever structure. The signal conditioning circuit is developed for the performance of the sensor, and the performance of the sensor is tested: the pressure signal is between 500N-1500N and the sensor has good output, the excitation frequency is controlled around 750Hz, the sensor response frequency with the minimum deviation will be obtained. If the excitation frequency is lower than 6Hz or higher than 2000 Hz, the deviation of sensor response frequency will exceed 5. The clinical anatomy of knee joint was studied and the sensor array arrangement was designed. The dynamic test of squat motion shows that the method is economical, reliable and practical, and can effectively collect and monitor the electrical information of knee joint control muscle group during human motion.
【学位授予单位】：昆明理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：R684;TP274

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