Research On The S&R Evaluatione Method Of Automobile Seats’ In Road Simulation Environment

Car noise can be divided into two categories:continuous noise and intermittent noise.Continuous noise will continue to occur under normal operating conditions,such as engine noise,tire noise and wind noise.This noise will make the user feel uncomfortable and should be eliminated first.With the continuous improvement of vehicle quality,such noise has been reduced,intermittent noise,including Buzz,Squeak and Rattle that BSR(abnormal sound)problem becomes more obvious,abnormal sound problems need to be eliminated,so as to continue to improve the vehicle quality.Abnormal sound phenomenon will occur in any two car on the relative movement of the surface,which dashboard,doors and seats are the most likely to produce abnormal parts of the car,accounting for more than 50 percent of the problem.The main causes of abnormal sound are dimensional tolerances,assembly accuracy,contact material compatibility,structural design,a variety of temperature and humidity environmental conditions and product quality.Manufacturers often require parts suppliers to have better sound performance,but the current test standards are not clear,suppliers do not know whether their products meet the customer’s standards,so the need for a clear test method and select the appropriate evaluation Indicators to better describe the product of the abnormal sound problem.In order to determine whether the specific parts has abnormal sound,mainly through the bench test to carry out subjective evaluation.Subjective evaluation over-reliance on experienced personnel and poor consistency.Based on the detailed description of the method of seat noise abnormality,this paper explores the evaluation method of seat abnormality.Through the correlation analysis of subjective evaluation results and acoustic parameters,this paper summarizes the objective acoustics that can reflect the subjective evaluation results parameter.The method is close to the engineering practice and can identify the abnormal sound problem.The main work of this paper is as follows:(1)The mechanism and influencing factors of BSR are studied,and the common BSR sound of automobile seat is summarized.Then the seat is divided into eight regions according to its BSR problems,and the subjective and objective evaluation is carried out for different parts of the seat.An objective and repeatable method for the measurement of seat’ BSR problem is established.(2)Select the typical road surface that can arouse the abnormal sound of seats,including cobblestone road,Belgian road and rough asphalt road.The choice of the road surface can simulate the actual use of the situation is relatively poor driving.Then,eight different prototypes are used to collect the road spectrum,and the collected road spectrum is analyzed and processed.At last,two vehicles were selected to carry out the vehicle road test and the seat abnormal sound test respectively.(3)The abnormal sound of the seat is tested by the typical road spectrum.Five long engaged in the development of BSR sound engineers,respectively,on the six seats in the typical road surface under the excitation of different parts of the three subjective evaluation.The method of grading.Finally,the experimental results are given to describe the subjective feelings of the people to the BSR sound.(4)The BSR sound generated by the seat on the typical road surface is measured objectively,and then the data are analyzed and processed.(5)To obtain the acoustic parameters and subjective evaluation results by correlation analysis,the study of the relationship between objective parameters and people’s subjective feelings,extract can well reflect the subjective feelings of the evaluation of acoustic parameters.By using the multiple regression method to get the seat different loudness,roughness and sharpness of the three acoustic sound index evaluation model based on the model,and the subjective scores were highly correlated,can be used to assess the noise,the noise is more close to the seat of the subjective rating.The method of seat abnormal sound evaluation is further improved.The innovation of subject:(1)A general load spectrum is generated and its validity is verified.First of all,select three typical road surface,for the same road surface,using eight different models of the load spectrum data acquisition,and then use the envelope method to generate the seat abnormal sound test general load spectrum.In the end,two models are selected to test the vehicle road test and the seat abnormal sound respectively,which proves the validity of the load spectrum.(2)The subjective and objective evaluation methods for different parts of the chair are proposed,and the acoustic parameters which can reflect the subjective evaluation results are extracted.Based on the method of multiple linear regression,the evaluation model of seat abnormal sound.There is a strong correlation between the evaluation model and the subjective score,which can be used to evaluate the abnormal sound,and to achieve a more subjective feeling.The method of seat abnormal sound evaluation is further improved.