The Development And Application Of Object-Orient Vehicle Noise And Vibration Signal Testing And Analyzing System

The noise and vibration of vehicle are related to environment protection, vehicle harshness and work life. How to control the noise and vibration has been one of the most important subjects in vehicle engineering. To achieve this goal, a powerful set of precise convenient testing and analyzing system is essential.Firstly, with view to the present characteristic of vehicle noise and vibration test and analysis, the paper introduces the domestic and international developing status and foreground in this field. Then, it expatiates the basal theory and the general structure of vehicle noise and vibration testing and analyzing system. Finally, base on this and with the conception of Object-Orient system development, such a system is devised and applied.The paper elaborates the system requirements in detail, defines the system functions and capabilities, and presents the general scheme of the system. It is composed of six subsystems, including onboard testing and analyzing portion, the pass-by noise portion, the speed testing subsystem, the engine rev testing subsystem, the throttle monitoring subsystem and the subsystem for synchronization and communication between onboard and outside signals. The paper also analyzes the demands for system software found on the general scheme, establishes the software model that consists of 4 objects-operator, interface-box, result data and result displaying. According to the software model, the paper creates the classes of objects with UML and develops the system software with C++Builder.After precision validated, the system is used to test and analyze local noise, interior noise, pass-by noise and engine vibration and noise. The results prove that the system is precise and helpful to accurately locate the source of noise and vibration, so it arrives at the requirements of functions and capabilities.In a word, the paper develops an integrated set of testing and analyzing system aimed at vehicle noise and vibration control, offering an important means to improve the vehicle NVH level. Though the structure of the system is complex, the employment of the Object-Orient technique ensures the development efficiency and makes the system more reusable and more expandable. Consequently maintenance and upgrade of the system are much more easier.