Time And Frequency Domain Analysis Of Vibration Fatigue And Exploration Of Its Prevention Methods

Land, sea and air a variety of vehicles (cars, tanks, ships, aircraft, spacecraft, etc.) will produce mechanical vibration when working in a dynamic environment. This vibration will cause muscle fatigue occupants, and especially the waist, neck, arm, leg fatigue is the most common stock. Besides, a long period of vibration fatigue can lead to chronic musculoskeletal injuries. Therefore, a study of the impact of dynamic environmental vibration and prevention methods of vibration fatigue on the human body has become an ergonomic and biomedical field important issue.Due to the difference of corresponding muscle fiber conduction velocity in a comfortable and fatigue situation, it will cause the different discharge of each skeletal, resulting in difference in surface EMG signal characteristics. Compared to the evaluation by the blood lactate content creators fatigue-in method for determining, the surface EMG is widely used in the field of medicine, kinematics, ergonomics and other as the virtue of its non-invasive, simple, multiple measurement points. Therefore, the surface EMG method is chosen as the main method of this paper experiments.This paper describes the generation mechanism of surface EMG, analyzes the main factors that interfere with the signal acquisition process according to the characteristics of EMG, and design signal acquisition experimental procedure of this article from both hardware and software; followed by the recording of experiments in this article steps. This article focuses on vibration fatigue analysis under the driving environment, so it needs to simulate driving a state as possible, building a driving environment. In this study, YS series electromagnetic suction fit shaking table excitation, and the subjects were placed in the car seat, to receive the EMG monitoring by Delsys software system, as a result, surface EMG recording and various skeletal muscle were displayed on the computer; then based on the monitoring of the EMG test samples, the signals were analyzed for its time domain and frequency domain analysis. The integral EMG value is regarded as fatigue evaluation criteria during time domain analysis, while the median frequency and the average frequency as fatigue evaluation criteria during frequency domain analysis. Through time and frequency domain analysis, we can get which skeletal muscle fatigue easily, when to fatigue, vibration frequency changes and fatigue indicator changes; Finally, acceleration-compensation, a method for preventing vibration fatigue was generated, which can be divided into single-direction acceleration compensation method, multi-directional acceleration and maximum compensation method. The basic theory is to find the largest muscle vibration acceleration direction and apply an impact on the opposite direction to low acceleration and offset the inertia force, reducing fatigue caused by vibration. Through applying the acceleration-compensation method in the corresponding skeletal muscle, we can obtain the difference of the EMG acceleration. By contrast, acceleration-compensation method can reduce the acceleration of the corresponding muscle from30%to80%, to relieve fatigue effect.