Study Of Vehicle Braking Performance Test Method Based On Virtual Instrument

Automobile's braking ability is one of the important items in safety check for vehicle, and it is the security guarantee for running. The traditional device for braking system test can't work according to the kinds of vehicles increasing year by year. Therefore, it is necessary to pay more attention to the research of the test system which is portable, intelligent and high efficiency. After analysis the condition of detection methods, a study of the evaluation system for braking performances on the basis of virtual instrument was porposed. Taking Lab VIEW as platform and using the idea of modular design, we have developed a portable test system for braking performance. Main contents and conclusions of the study are listed as follows:1) This paper has analysed the evaluation indicator for braking performance and the methods of checking brake system systematically. After introduction of braking efficiency, homeostasic of braking efficiency and stability, the paper also points out that the slip rate is one of the important parameters for checking braking system within ABS. A portable test system for braking performance based on virtual instrument was proposed, according to the shortage of the traditional methods.2) It studied signal denoising and feature extraction of test signals according to the theory of signal process, and researched the determine methods for vehicle speed and braking distance. This article designed a fourth-order butterworth low-pass filter to deal with the interference and verified the rationality using an example. The speed of vehicle and distance of braking are important parameters for evaluation. This paper have analysed the methods for these parameters and it is a theoretical basis for data processing.3) This paper has researched the components of portable test system and the question of carry out. Hardware as the basis of test system includes sensors, data acquisition, portable computer and signal conditioning device. Software is the core of the test system, complex functions were broken down into small modules easy to implement and understand effectively and gradually using modular design in software. Focus on data acquisition module, signal processing module and a remote- controlled detection system module, in addition to give the design flow chart, explains the specific implementation of its functions and methods in detail. It is really reflects the thinking of "software is the instrument" using software to replace some hardware.4) For the environment interference, the measures of anti-jamming for test system have been researched. This article introduces the anti-jamming design form both hardware and software. The anti-jamming design for hardware mainly contains shielding, grounding, eliminating interference with other measures to reduce the interference power. The design of anti-jamming in software part achieved good results which from the test microscopic point of view to solve practical problems. Finally, the simulation for the speed of vehicle and wheel, pedal force have been done successfully, The curve of slip rate, speed and pedal force displayed on the front panel after processing. It provided a good theoretical basis for evaluate vehicle braking performance.The results show that, the system has a short development cycle, low cost, easy to expand and easy to carry etc, and it is the direction for test based on virtual instrument.