Research On Sound Management System And Sound Simulation Method For Electric Vehicle

Electric vehicles are almost silent at low speeds,which greatly reduces city noise.At the same time,a growing number of studies and statistics have shown that too quiet driving at low speeds in electric vehicles can make it difficult for road users around them to detect the potential safety hazards of approaching vehicles.Therefore,this paper studies the sound simulation method and designs a sound management system for electric vehicle,which aims to simulate the real-time and real-life traditional engine sound which can indicate the running state of the vehicle according to the speed of the driving motor when the electric vehicle runs at low speed as a reminder to road users around electric vehicles.In this paper,firstly,the sound simulation method is studied,and a sound simulation method based on particle synthesis method is adopted.In that method,the sample of the engine sound unit are rearranged accord to the rotation speed to simulate the engine sound.The quality of the engine sound unit sample therefore determines the effect of the simulated engine sound.The engine sound unit sample is determined by the accuracy of the extracted engine sound characteristic parameters.In view of this,this paper proposes an improved method to extract the non-steady signal characteristic parameters based on the short-time Fourier transform.It is proved by signal simulation that the method has higher extraction precision.Secondly,by referring to the related literature and data,the composition of engine sound is determined and the model of engine sound is established.An improved non-steady state signal characteristic parameter extraction method is used to extract the feature parameters of a pre-processed engine sound signal under acceleration condition.The feasibility of the extracted characteristic parameters is verified from both subjective and objective aspects.The results show that the extracted characteristic parameters can be used in engine sound simulation.On the basis of the engine sound model,the extracted characteristic parameters are fitted to obtain the sound unit samples in the full speed range.According to the speed of the engine,the samples of the sound unit are rearranged and combined to simulate the sound of the engine under an acceleration condition.The results of subjective evaluation of the simulated engine sound show that the simulated engine sound retains the characteristics and components of the original engine sound,which indicates that the sound simulation method based on particle synthesis is feasible in the simulation of engine sound.Next,according to the principle of the sound simulation method and the aim of the sound management system of electric vehicle,the sound management system is modularized.According to the function that each module is responsible for,the software and hardware are designed in detail,and the sound management system of electric vehicle is built successfully.Finally,taking the characteristics of vehicle sound warning system in EU Regulation No.540 / 2014 as the test evaluation standard,the upper computer software is operated to simulate automobile CAN signal,and the sound management system of electric vehicle designed in this paper is debugged and tested.The results show that the sound management system designed in this paper can simulate the realistic engine sound,and the sound can indicate the driving status of the electric vehicle.