Experimental Study And Modeling Of Muscle Fatigue Of Upper Limb In Push Operation

Push operation is required to be implemented by operators in many industries,which is widely used in work and life.When people work in fatigue state,they often have problems such as loss of enthusiasm,inattention,decline of thinking and judgment ability and physical activity ability,which increase the probability of operation error or unsafe behavior,and eventually lead to accidents and injuries.Aiming at the problem of muscle fatigue in push task,this paper designed two muscle fatigue experiments and mental fatigue tests after experiment 1?Muscle fatigue rate of upper extremity?,and systematically studied the fatigue rule in push task.First,through the selection of muscle fatigue attribute index and muscle fatigue model,the muscle fatigue rate K in index muscle strength decline model is selected to describe the upper limb muscle fatigue attribute in push operation.The experimental results show that this parameter can effectively describe the fatigue properties of upper limb muscles.Among them,the average value of muscle fatigue rate k of male subjects was 1.18min^-1;the average value of muscle fatigue rate k of female subjects was1.07min^-1.Neither gender nor BMI could predict the muscle fatigue rate K.Mental fatigue test showed that the test before and after the experiment was significantly different,mental fatigue increased with the increase of physical workload.In order to explore more influencing factors of muscle fatigue in push operation,an experimental system simulating push operation is designed in this paper.Different working time intervals are set.At the same time,each group of subjects bears different relative loads in different thrust angles to seek the rule of muscle fatigue in intermittent operation and evaluate the main factors affecting muscle fatigue in push operation.The results of variance analysis show that the relative force has a significant impact on the rating of perceived fatigue?RPE?,and the thrust angle has a significant impact on the subjective fatigue score,but there is no significant correlation between the working time interval and the subjective fatigue score.Through the muscle fatigue rate measured in Experiment 1,the prediction equation of push operation muscle fatigue is established.The scatter diagram shows that the difference between the measured residual force value and the predicted residual force value is small.Through the real-time force curve,it is found that there are many phenomena of the general attenuation of the thrust from the beginning to the end.Because of the function of the muscle itself,that is to manage its own fibers and change the position of the activation center of the muscle itself.Finally,the concept of force application attenuation is proposed,which is defined as the average force in the first half of each experimental process minus the average force in the second half.Correlation analysis shows that there is a strong correlation between the impairment of exertion failure and RPE,which can reflect the degree of muscle fatigue.This provides a new and real-time method for muscle fatigue monitoring of push operation.The advantage of using force attenuation value to evaluate muscle fatigue is that it only needs to measure the force in real time through sensors,and it can be evaluated and forewarned in real time through a simple program.It is simple and easy to use in engineering and has strong practicability.The research results of this paper can be used to understand and control the fatigue state of push operation,reduce the injury of muscle fatigue,also can be used to evaluate the task design and improve the overall work performance.The thesis includes 33 figures,21 tables and 74 references in this paper.