Sitting Posture Support Design And Biomechanical Modeling Of The Musculoskeletal Model Based On Anybody

Incidence of d low back pain (LBP) and lumbar disc herniation and other diseases is high in the professional drivers. Some studies show that award sitting postures and unreasonable seat design does increase the association with the presence of LBP. Establishment of biomechanical model and bone muscle system model of driver contribute to analysis causes of occupational diseases, more effective improcement scheme of car seat will be given and verified according to the human body biomechanics model. It is important to the health of drivers and prevention of occupational disease.This study analyzed the impact of poor posture and unreasonable lumbar support on human musculoskeletal system based on AnyBody Modeling System (AnyBody Technology A / S, Aalborg, Denmark). This study builds seated human musculoskeletal model and studies factors which may affect the musculoskeletal diseases of drivers. The main works are as follows:(1) Establish two dimensional driver biomechanical model. According to the characteristics of driving posture, a rigid biomechanical model is established, and the joint of the driver is simplified as a hinge structure. Considering to relative quality and length distribution of driver and systemic stress condition, driver’s waist force under the condition of single point support is derived according to the Newton first and third law and moment equilibrium. Comparison of the two state formulas can be drawn when pedaling with right foot, waist stress will become large and leading to L4/L5 lumbar pressure increase. This could provide some ideas for improving design of seat.(2) Establish human skeletal muscle model based on AnyBody Modeling System. The driver cab interaction model is established based on AnyBody Modeling System(AMS) with detailing introduction of the principle of AnyBody software modeling. And the initial state of the interaction model between the driver and cab is defined. In order to facilitate researching, this paper makes a classification of muscle groups according to driving posture characteristics of driver, and analyzes driver’s muscle model. The results showed that activity of driver leg muscles, abdominal muscles and waist muscle groups were significantly increased with frequent pedaling.(3) Analyze the impact of changing the distance between pedal and seat on the driver’s comfort. This study analyzed the effects of changing the distance between the pedal and the seat on the leg, back and abdominal muscle fatigue of the body and the changes of the waist force, the five distances of 95cm,97cm,99cm,101cm and 103cm were mainly selected. Firstly, having a simulation analysis on changing distances between pedal and seat for studying each muscle activity levels and L4/L5 lumbar force using Anybody software. Secondly, muscle oxygen data of leg, waist and abdomen were measured by near infrared spectroscopy (NIRS). At the same time external force of L4/L5 lumbar spine was measured by force sensor. The results show that distance between pedal and car seat has a great influence on the human body’s skeletal muscle system. The proper spacing between pedal and seat is beneficial to the comfort and portability of driver.(4) The improvement of the seat is proposed and verified based on the theory of pelvis and lumbar vertebra composite support. The design of the seat is improved. A "combined pelvic and lumbar support" theory is put forward as the driver always inadvertently keep bad driving posture and the unreasonable design of the seat, and the purpose is keeping driver’s waist have a reasonable support to maintain proper posture. This theory must accord with ergonomic design, effectively reduce the level of back muscle activity.To test this theory, first of all, changing the driver support conditions based on human-seat model, and get gastrocnemius,musculus vastus lateralis,erector spinae and rectus abdominis muscle activity and muscle force with simulation calculations. Secondly, erector spinae muscle oxygen content was measured by NIRS in two kinds of support conditions. The results show that "combined pelvic and lumbar support" theory can effectively reduce the level of muscle activity, and reduce the force of lumbar.