| Tractors,as self-propelled power machines that pull and drive working machines to complete various mobile operations,have been widely used in various fields of agricultural production.With the continuous improvement of agricultural mechanization in China,people’s requirements for tractor comfort are also increasing.In actual work,due to the poor working environment,tractor drivers are more likely to feel pain and discomfort in their back and buttocks,and face serious health threats.The tractor seat is one of the main human-computer interfaces in the cab,and the seat design will directly affect the driver’s comfort.Therefore,in order to meet the comfort needs of tractor drivers and conduct a reasonable and objective evaluation of seat comfort,this paper studies the tractor seat comfort based on the distribution of body pressure to evaluate the comfort of tractor drivers during operation,mainly including the following parts:First of all,by combing the relevant comfort concepts of domestic and foreign scholars,on the basis of the comfort concept,the subjective and objective evaluation methods of seat comfort are discussed respectively,focusing on the key theories,technologies and applications of the objective evaluation of seat comfort based on the pressure distribution of the human-seat contact surface and the finite element simulation analysis method,and comprehensively summarizing the theory and evaluation methods of tractor seat comfort.Secondly,the static body pressure distribution experiment of tractor seat is designed to obtain the pressure distribution data between the human body and the seat interface,and the body pressure distribution affecting the seat comfort is studied in detail to explore the influence of different body mass index(BMI)and driving time on the tractor seat comfort.At the same time,the subjective evaluation table was made with reference to the Likert scale,and the subjective comfort score of the experimenter was obtained.The correlation between BMI and driving time,subjective comfort and objective body pressure distribution index was studied using SPSS data analysis software.It was found that BMI was significantly correlated with subjective comfort and body pressure distribution,especially in the hip region;However,there was no significant correlation between driving time and subjective and objective data.Then,the seat finite element simulation analysis process is introduced in detail,and the seat comfort finite element analysis method based on LS-DYNA is proposed.The finite element models of human body and tractor seat are established respectively,and the human-seat coupling finite element simulation analysis model is constructed.The Tekscan body pressure distribution measurement system was used to measure the static body pressure distribution index of the tractor seat on the subjects,and the simulation results were compared to verify the effectiveness of the simulation analysis method.At the same time,explore the influence of different percentiles of human body on the body pressure distribution index.Different percentiles of human body models have obvious differences in the peak pressure index and the displacement distance of seat cushion and backrest.The results can further deepen the understanding of seat comfort.Finally,in order to realize the quantitative evaluation of tractor seat comfort accurately and reliably,a comprehensive evaluation method of tractor seat comfort based on subjective and objective combination weighting model is proposed to solve the problem that it is difficult to conduct quantitative evaluation of tractor seat comfort only from a subjective or objective perspective due to the complexity of the comfort evaluation problem.Through literature research and expert questionnaire,combined with the frequent occurrence of human discomfort in the operation,the evaluation index system of driving comfort is constructed.At the same time,the combination weighting method is used to balance the subjective experience,data and objective information of experts,while retaining the subjective opinions of experts,avoiding the weight imbalance,and obtaining the comprehensive weight.The multi-level fuzzy comprehensive evaluation theory is introduced to convert comfort evaluation into quantitative evaluation,and the mapping relationship between subjective evaluation and objective data is established.Finally,the comfort weights of left upper back,right upper back,left lower back,right lower back,left hip,right hip,left thigh and right thigh are 0.130,0.094,0.133,0.105,0.193,0.162,0.085 and 0.098. |
