Study On The Influence Of Ergonomic Seat Parameters On Comfort

Sitting posture is currently the most common posture in work,and the number of people with prevalent low back pain caused by prolonged sitting is increasing and becoming younger.Today,with the continuous improvement of living conditions and the increasing popularity of the concept of "proactive health",consumers’ demands for seat comfort have also increased simultaneously.In order to improve the customized design level of ergonomic seats,this article studies the impact of some parameters of ergonomic seats on human comfort.The main research content is as follows:(1)Analyzed the biomechanical characteristics of the lumbar back and buttocks and legs in a sitting posture,as well as the fatigue status under prolonged sitting,and summarized that the specific locations where discomfort is more common in the human sitting posture are the L4-S1 segment of the lumbar intervertebral joint and the vicinity of the hip ischial tubercle.Explored the impact of multiple seat parameter changes on the human body,and summarized the advantages and limitations of the subjective and objective comfort evaluation system for ergonomic seats.(2)A biomechanical coupling model of human chair sitting posture was established using AnyBody muscle bone model software.Four parameters of 252 groups of variables,namely,the height of the front edge of the seat,the inclination of the backrest,the height of the lumbar support and the amount of lumbar support protrusion,were selected.The activation degree of the longissimus,rectus femoris,quadratus femoris and the joint force between L4-L5 and L5-S1 of the lumbar spine were simulated.The obtained data were compared with the relevant research literature data,and the validity of the model in this paper was verified.(3)A BP-GA neural network model for evaluating the comfort of ergonomic seats was constructed,and the simulation results were input into the network for training and testing.The genetic algorithm was used to conduct global optimization in the trained neural network model,and the conclusion was reached that the highest level of human comfort is achieved when the protrusion height of the front edge of the seat surface is 35mm,the waist support height is 100mm,the waist support protrusion is 70mm,and the backrest angle is 120°.(4)A seat model structure that meets the requirements of adjustable research parameters was designed,and the prototype was processed and constructed.Surface electromyography(EMG)signal equipment was used to measure the activity signals of the lumbar longest muscle and anterior thigh rectus muscle of 10 subjects in the optimized seat parameter standard group and control group,verifying the effectiveness of the established BP neural network model.The research results of this article indicate that the four parameters of seat front edge protrusion height,lumbar support height,lumbar support protrusion,and backrest inclination have a significant impact on the comfort of ergonomic seats.The BP-GA neural network can be used to obtain an optimized combination of these four parameters.The design method in this article has theoretical guidance significance for improving the customized design level of ergonomic seats.