The Research Of Fuzzy Self-Tuning Control Algorithm Of Automobile Adaptive Cruise Control System

As the gradually enhancing of our country's road quality classification, especially therapid development of the highway, now, how to increase the traffic safety and capacity onpresent infrastructure, becomes a problem focused by all. Normally, Intelligent Vehicle (IV)and Intelligent Transport System (ITS) are thought to be the best way to solve the problem.Driver Assistant System (DAS) is considered as the transitional stage from general drivingand absolute autonomous driving. Automobile Adaptive Cruise Control system (ACC), forits directly longitudinal driving control of vehicle, can obviously improve the active safetyand riding comfort, becomes the focus of DAS now. To realize the accurate longitudevelocity control of vehicle, basing on the strong nonlinear and time-varying dynamicscharacteristic in longitudinal vehicle control is the key theme in research.For the final purpose of DAS is partially or fully controlling vehicle to replace of realdriver, as a working well ACC system, its control character should be basically the samewith the most skillful and lofty driver's handling. Developed on formerly AutomobileAdaptive Cruise Control system based on driver optimal preview acceleration model, thisthesis simulates handling character and understanding with vehicle performance of realdriver, presents fuzzy self-tuning control algorithm of automobile Adaptive Cruise Controlsystem.Firstly, this thesis aiming at the strong nonlinear dynamics characteristic of vehicle inlongitudinal control, linearizes dynamics characteristic of vehicle in longitudinal controlwith time-varying simple linear model, identifys linear model parameter with least squaremethod on-line, introduces parameter identifyed on-line algorithm of vehicle longitudinaldynamics characteristic linear reference model. Describe vehicle longitudinal dynamicscharacteristic with the model which parameter is indentifyed on-line, correcte optimalpreview acceleration, acquire input of vehicle longitudinal control system on-line, realizevelocity controller parameter self-tuning algorithm.Secondly, aiming at solving the accuracy and real-time problem in parameter indentifyedon-line under complex conditions, introduced fuzzy control system in vehicle longitudinalcontrol system, presented fuzzy controller of vehicle longitudinal control. Some estimateindex are presented to describe vehicle longitudinal dynamics characteristic, based oncommon fuzzy controller, such as index of reaction error in vehicle longitudinal control,index of reaction velocity in vehicle longitudinal control, index of steady performance invehicle longitudinal control, index of acceleration error intensity and index of accelerationerror transformation. Though evaluating the estimating index of controller performance,adjust the parameter of fuzzy controller automatically. The parameter's self-tuning methodis made up of primary adjusting and accurate adjusting. Primary adjusting is done every 5seconds. Accurate adjusting is done in every sample time. Finally present fuzzy self-tuningcontrol algorithm of automobile Adaptive Cruise Control System.Finally, applying the vehicle dynamic model of twenty-ninth degree of freedom, which isfounded by State Key Lab of Automobile Dynamic Simulation of Jilin University, simulatethe fuzzy self-tuning control algorithm of automobile Adaptive Cruise Control system,proved validity and effective of the algorithm.In this paper, the innovative points are simulating the real driver handling behavior,presenting the fuzzy self-tuning control algorithm of automobile Adaptive Cruise Controlsystem, which can be adaptive when vehicle driving condition changes or disturb exists.The controller's self-tuning on-line not only guarantees the velocity control precision, butalso efficiently reduces workload of controller design and match.