Experimental And Numerical Simulation Study On Ergonomics Of Soldier And Individual Equipment

The soldier system is considered as the complex and typical people(soldiers)-Machine(equipment)-Environmental(tactical missions and environment)light weapons system.The ergonomics of soldier system are proven to improve the level of combat safety,comprehensive combat effectiveness and comfort.How to reduce the error rate of equipment operator and enhance the comfort soldier during fighting are mainly focused in this paper.Experimental and numerical simulation methods are used to analyze the ergonomics of soldier system,and the main work and research of this paper as follows:A helmet-head-neck musculoskeletal model is established to investigate the effect of helmet on soldier’ head and neck muscular activities.In the sagittal plane,the neck muscle activity increases if the centroid position of helmet changes from-40mm to 23mm and from53.3mm to 60mm.The neck muscle activity decreases at first and then increases when the centroid position of helmet changes from 23mm to 53.3mm.In the coronal plane,the neck muscle activation has little change when additional lateral bending moment is less than the corresponding threshold.Enhancing the tightening force is advantageous to enhance the stability of helmet,while increases the activation of jaw muscles.The soldier balance capability test is completed to investigate the effect of the load on the soldiers.The amplitude and the envelope area of pressure center increase linearly as the load increasing.However,the speed of the plantar pressure center decreases when the load increasing.The positions of the load affectes the soldier balance capability,but did not show significant.The types of positions of the load impaired the soldier balance capability,and the right rear load,left anterior load and all around load impair the soldier balance capability,while all around load is minimum difference to the no load condition.The gait of solder was obtained to investigate the effects of loads on solder in this paper.The tests results show that the angle of subtalar joint,foot flat phase,the max force and the unbalance foot were increased as the load increases,while the hip joint range reduced as the load increases.Generally,those testing index did not showed significantly,unless the weight of load exceed 20kg.In this paper,the effects of the positions of load are also studied,and all around load is considered as the mostly similar to without weight condition.The shoulder peak stress is obtained to evaluate the effect of load on subjective comfortable.The tests results show that the shoulder peak stress and comfort evaluation score increases linear as the load increasing.There are related between shoulder peak stress and comfort evaluation score.If the soldier bear the same load,evenly arranged the load is beneficial to relieve shoulder stress and improve comfortable.The Individual weight musculoskeletal model is build to investigate the effects of load weight on soldier,and the maximal muscle activity is used to evaluate the comfortable.The maximal muscle activity increase as the load increase,while the maximal muscle activity remarkable rise when the load exceed 20kg.As the load centroid position moving downward along the height direction,the maximum muscle activity decrease linearly.In the longitudinal direction of the body,the maximum muscle activity decrease as the load centroid position closing to the back.In the lateral direction,the maximum muscle activity decrease exponentially with the load centroid positional deviation of the spine.A motion capture system and plantar pressure measurement system are used to get the motion trajectory and plantar pressure of pistol shooting and a man-pistol system model is established.The results show that there is close correlation between pistol movement and foot force/pressure center position during the continuous shooting.For 54 pistol,the shooter has gone through the passive response phase and active response phase,and the active response startes at 250ms(SD=62.9ms).The shooting is also a process of continuous learning behavior consciousness,the muscle activity three times and the first two activity is due to the movement of pistol while the last activity is due to the shooter active response phase.Fatigue and weakly gun control ability occurre after 4 consecutive shots.A motion capture system and plantar pressure measurement system are used to get the motion trajectory and plantar pressure of rifle shooting and a man-rifle system model is established.For 15 continue shoots,the entire shooting process can be divided into four stages:aiming phase,passive response phase,active response phase and gun revenue phase.The ability of control rifle is differences between horizontal,shooting and vertical directions.The experience show that the ability to control the shooter on the vertical direction significantly better than horizontal.The movements discipline of the markers set on the body were similar to rifle,showing peaks and valleys variation.The motion amplitude of the body changed smaller as the joints far away from the rifle.During the 15 continue shoots,the muscle activity changed 15 times,and the max activity appeared at the first shoot.The shooter active response phase appeared from the sixth shoots.During the shooting,the reaction force of left elbow was greater than right,and the reaction force of left shoulder was greater than right.The proximo-distal force of L5 lumbar joint was max,and the medio-lateral force was similar to antero-posterior.