Design Of Automotive Brake's Vibration And Noise Testing And Analytic Instrument Based On Virtual Instrument

The braking performance is very important for all vehicles. If the design of the brake is unreasonable, the friction material is aging or the braking condition is changing, the intense vibration can be brought when braking, and going with the noise. We always take trial and error depending on experience to depress braking noise. It is not only the number of testing equipments and the workloads of testing will be increased, but also the cost of the testing will be higher, if we use traditional hardware testing equipments. Based on the concept of virtual instrument, combined with the vibration and sound measurement and analysis techniques of disc brake, and using Graphic Programming Language LabVIEW, the subject constructs a vibration and sound measurement and analysis system of the brake based on virtual instrument under Windows environment. And the system carries on a research in view of the problem about brake squeal of a disc brake.Firstly, the paper introduces the conception and content of virtual instrument, and then discusses the generation mechanism of braking noise and parts vibration detailedly. After finished the theory analysis, the collectivity design of the system is developed with Graphic Programming Language LabVIEW. Then the hardware selection and configuration, and the software structure and its modules' function are introduced. At the same time, the functions of the system is verified and corrected. Finally, verifies the correctness of the program and the reliability of the system through test in practice. And comparing the experimental result with the theoretical calculation result to research the relation between the natural frequency of parts and the braking noise frequency. It is found that, the main reason for braking noise is resonance vibration, which provides the basis for more optimum design of brake and depressing braking noise. The testing and analytic system of automotive brake's vibration and noise adopts the idea of modular design and offers the functions of collection, measurement, storage, analysis and display. The functions of FFT transition, correlation, power spectrum, third-octave analysis and etc are realized in the software. On the basis of completing basic measurement functions of the brake vibration and sound experiment, the system expands other testing functions.