Research On Automobile Exhaust Measurement Mode Controlling System Of VMAS195

The testing technology of automobile exhaust pollutants of VMAS195 is the key technology for the implement of Inspection/Maintenance system. The theory, technology and application of automobile exhaust measurement mode controlling system of VMAS195 are researched theoretically and experimentally in this article. The results are of theoretic significance and practical value in applied engineering.Based on the analysis of automobile road driving resistance and dynamics when the automobile is running on the dynamometer, the mathematic model of automobile road driving resistance simulated by the dynamometer is founded. On the basis of the principle that the same automobile driving wheel transient angle acceleration should be produced in the action of the same the change of driving forceΔFt when the automobile is running on the road and on the dynamometer, the mathematic model of automobile road driving resistance simulated by the dynamometer is established in the way of the loaded torque incrementΔTe, which provides the basic theory when the automobile is running on the dynamometer.Introducing the made mechanism and the influenced factor of the automobile emission exhaust primary pollutant, Controlling the VMAS195 testing mode is necessary. According to the characteristic of VMAS195 testing mode, the overall design is made. The VMAS195 testing mode control system that is constructed mainly consists of dynamometer, industrial controlled computer, rectifier voltage regulating devices and driver aid. The whole system adopts human-computer compound controls strategy.The performance of eddy current dynamometer is influenced by magnetizing current and rotating speed at the same time through theoretic analysis and experiments. Because of the nonlinear traits, time-varying and slow responding, the steady and dynamic model of absorbing torque controlled by eddy current dynamometer is brought forward.The control method of VMAS195 testing mode control system is designed, which adopts Dynamic Matrix Control (DMC). To reduce the absorbing torque interference of eddy current dynamometer caused by variable rotating speed of dynamometer, the decoupling control project of the feedback predictive compensation torque for automobile speed is put forward, which is used by VMAS195 testing mode.The dynamometer torque controller of VMAS195 is designed and developed based on DMC and decoupling control. The DMC with model gain coefficient and decoupling function is used. DMC predictive control speeds up torque response of dynamometer; Model gain coefficient improves the robustness of control and the adaptability of the system to different tested automobile types and testing conditions; the application of the feedback predictive compensation torque decoupling for automobile speed reduces effectively the maximum impacting torque value of VMAS195 testing.An experimental software system of VMAS195 driving mode control is designed and developed by adopting the associative method of two high program languages of LabVIEW and Visual C++. And the experiment has been carried out. The experiment results show that the systemic project is reasonable and the overall design is feasible.