Intelligent Vehicle Control Based On Extended State Observer

During the past decades, with the rapid development of economy and technology, the prevalence rate of vehicles is more and more high, and it can be a threat to life and property of people, although vehicles have brought much convenience to us. With the study of intelligent vehicle control, the. number of traffic accidents can be decreased, the traffic flow can be improved and the air pollution can be reduced and so on. Therefore, research topics about the intelligent vehicle control have attracted much attention of investigators and lots of results have been achieved. In addition, time delay is inevitable in the practical intelligent vehicle control system, and the control performance even the stability of the system may be affected by the time delay. Consequently, it is important to investigate the problem of the intelligent vehicle control system with time delay both in theory and practice. In this paper, the time delay is taken into consideration, and a technology named extended state observer is used for studying the control problems of autonomous vehicle following system and active vehicle suspension system.The main results in the thesis are as follows:In chapter 1, the background of this thesis is introduced and the research situation of the intelligent vehicle control including autonomous vehicle following control and active vehicle suspension control is recalled both at home and abroad.In chapter 2, the problem of autonomous vehicle following control based on an extended state observer is investigated. First, by introducing a platoon following model with a known time delay and an unknown time delay, an extended state observer is constructed for estimating both the total disturbance and states of the vehicle following system. Then, the states estimated by the extended state observer are used for the controller design, and based on the Lyapunov stability theory and linear matrix inequality(LMI) approach, a stability condition of the autonomous vehicle following system and a design method of the controller are presented. Finally, simulation results of Matlab/Simulink show that the designed controller can keep a safe distance between neighbouring vehicles in the presence of disturbances.In chapter 3, the problem of active vehicle suspension control based on an extended state observer is investigated. By establishing an active vehicle suspension model with control input time delay for a quarter of vehicle, an extended state observer is constructed to estimate both the total disturbance and states of the active vehicle suspension system. Then, the states estimated by the extended state observer are used for the controller design, and a design method of the feedback controller is given in terms of linear matrix inequalities. Finally, simulation results of Matlab/Simulink show that the designed controller can limit the influence of the road disturbance on the suspension deflection in a small range.In chapter 4, some conclusions of the thesis are summarized, and some research issues in future are proposed.