Construction And Application Of Sitting Comfort Evaluation Model For Electric Locomotive Cab

As the main carrier of the interaction between the driver and the vehicle,the cab of the wide-gauge electric locomotive is directly related to the driving experience and operational safety of the drivers and passengers.In order to improve the design level of China’s export electric locomotive products,a multi-dimensional analysis is conducted on the characteristics of freight locomotive drivers who drive for a long time and have persistent and repetitive driving tasks.The driving experience of the driver is quantitatively analyzed by establishing a suitable mapping relationship between subjective feeling and objective evaluation indexes of sitting comfort.Considering body pressure distribution and subjective comfort between the driver and the seat contact interface,the evaluation model of sitting position comfort was formed.The main research contents include:First,in order to explore the relationship between the shape design of the seat back and the driver’s sense of fatigue and comfort,a driver’s seat comfort evaluation test based on pressure distribution is designed.The results show that the driver’s seat can’t meet the driver’s comfort requirements,and in the process of pressure data collection,the test links were strictly controlled,and 12 groups of pressure distribution data and corresponding subjective scores were finally obtained,which provided powerful sample data for establishing a sitting comfort evaluation model.Secondly,according to the selection criteria of evaluation index of sitting comfort and the existing research results,it is shown that the back,waist,buttocks and thighs of the human body are highly sensitive.For the parts with higher frequency,the human body is divided into five parts,including upper back,lower back,waist,buttocks,and thighs,to construct a sitting comfort evaluation index system.By using AHP to limit entropy weight method and correcting the objective data with subjective values,the weights of the influence of each index on the sitting comfort are obtained.Then,the reverse design method based on key points is used to improve the design of the backrest of the driver’s seat.After comparative analysis,two optimal schemes are finally selected.The improved design scheme is verified,and the subjective and objective test results are consistent.The test results show that the design scheme 1 and the design scheme 2 are better than the seat back prototype.Taking height,weight,ideal backrest pressure distribution difference and seat cushion circular pressure gradient as independent variables,and overall subjective perceived comfort score as dependent variable,the SVR regression prediction model was constructed using MATLAB LIBSVM toolbox to carry out regression simulation on driver seat comfort.In conclusion,the prediction accuracy of the model is high,and the ideal pressure distribution difference of the backrest and the circular pressure gradient of the seat cushion can be further applied to the cab seating comfort evaluation model as objective parameters.Finally,a three-order response surface model with four variables and one output was established by taking four pressure distribution parameters,including cushion circular pressure gradient and ideal pressure difference of backrest,total pressure and maximum pressure of ischium nodal,as design variables,and the overall subjective comfort score as response values.The reference standard for the evaluation of sitting comfort was obtained by using particle swarm optimization(PSO)algorithm.That is,values of pressure distribution parameters of people with different body sizes in high comfort state.