Study On The Evaluation Of Fatigue Degree Of Human Body In Incremental Load Exercise

Human fatigue is an important cause of production efficiency decline and accidents.Scientific and reasonable human body fatigue assessment method is of great significance for improving production efficiency,reducing accidents,reasonably arranging working time and ensuring the life,health and safety of workers.Based on heart rate,relative energy metabolism rate and human body temperature,this paper establishes human body fatigue evaluation index system,applies analytic hierarchy process(AHP)and comprehensive evaluation method based on fuzzy set theory to assess human body fatigue degree in incremental load exercise,and establishes comprehensive evaluation scale of fatigue degree.The main research contents and conclusions are as follows:(1)To explore the possibility of heart rate,energy metabolism rate and body temperature as the evaluation indexes of human fatigue.The human heart rate,relative energy metabolic rate and body temperature change regularly in the increasing load exercise.Among them,heart rate and relative energy metabolic rate increased with the increase of load.The temperature of the human body showed a downward trend,and the degree of decline was different in different parts,especially in the anterior leg area.(2)The evaluation method was selected to determine the fatigue level of human body under different load intensity.The weight coefficients of cardiopulmonary function parameters and body temperature of the first grade indexes were calculated by AHP as 0.667 and 0.333,while the weight coefficients of the second grade indexes,heart rate,relative energy metabolism rate,calf anterior region,calf posterior region,knee joint and femoral anterior region were 0.667,0.333,0.598,0.076,0.123 and 0.203,respectively.The comprehensive evaluation method based on the fuzzy set theory was used to assess the human body operating fatigue degree in the incremental load movement.The results showed that when the load was 50W~60W,the performance was non-fatigue.From 70 W to 120 W,moderate fatigue was observed.From 130 W to 170 W,it shows severe fatigue.Above 180 W,it shows extreme fatigue.(3)Assess the fatigue level of human body.Based on HR,RMR and anterior calf temperature,a comprehensive assessment scale of human working fatigue was established.Taking HR greater than 154 BPM as an example,extreme fatigue occurs when RMR is greater than 1.64 or the temperature difference in front of the calf is less than-0.42 C;severe fatigue occurs when RMR is greater than 3.75 or less than 6.80 and the temperature difference is greater than-3.62 or less than-1.8 C;moderate fatigue occurs when RMR is greater than 2.09 or less than-1.70 C;and moderate fatigue occurs when RMR is greater than 1.64 or the temperature difference is greater than-0.69 or less than-0.42 C.When RMR is less than 1.63 and temperature difference is greater than-0.41 C,it is not fatigue.Therefore,when the evaluation of fatigue degree is not determined by a single factor,it is the result of the interaction of multiple indicators.