The Research On The Measurement And Control System Of Small Vehicle Braking Performance

The braking performance of vehicle is an important guarantee for driving safety. Therefore, it is of great significance to test vehicle correctly, rapidly and effectively. Virtual instrument in line with the principle that "software is instrument" reduces the cost of hardware in the system, shortens the development cycle and strengthens the expansion capability of the system. This design is based on the LabVIEW platform, combining the virtual instrument technology with the technology of testing, constructing a braking performance testing system which is powerful, with reliable performance and with convenient operation.This paper firstly introduces the sorts of testing system, principles, results and the advantages and developments of virtual instrument. Then the mechanical part of the testing platform is completed according to the principle of inertia braking.The hardware of the testing system is composed of frequency converter, electric motor, disk light beam encoder and data acquisition card. Frequency converter controls the rotational speed through controlling the frequency, and data acquisition card gathers the pulse signals output of disk light beam encoder. This whole hardware system lays a firm foundation for the braking performance test.This design adopts three methods to control the rotation of motor, which are PID control, fuzzy logic control and PID-fuzzy logic control, and the control effects are simulated. The results have proven that PID- fuzzy logic control has the best result.The software of this testing system has fulfilled the function of communication of serial port, PID control algorithm, fuzzy logic control algorithm, display of control diagram, data preservation. The interface of the software is clear with good human-computer interaction.This paper finally introduces the operational steps under practical testing, and analyzes the comparison of effect of speed control under the current situation and the test of braking performance. The results have proven that this system has met the expected functional requirements with high accuracies of test and control.