Study On Distributed Adaptive Control Of Vehicle Platoon

Vehicle platoon is the cooperative motion of a group of automobile.Its prominent advantages in improving highway capacity,reducing traffic accident,reducing environmental pollution,improving operation efficiency as well as enhancing traffic safety have gained aroused attention.This dissertation addresses the problems of vehicle platoon with uncertain driving resistance,actuator saturation,velocity constrains and information of velocity and acceleration unmeasured.First,the current states and the main problems and basic engineering requirements of vehicle platoon are described.Then,a basic model of vehicle platoon is constructed based on Newton's laws of motion.Next,the basic mode are modified and optimized based on the detail requirements of each problem,and a series of control algorithms are designed to solve each problem.Numerical simulations verify the feasibility and effectiveness of the proposed control method.The main research work and contributions of the dissertation are summarized as follows:1.Considering the effects of external disturbance,the uncertain driving resistance of vehicle is analyzed and used to construct the model of vehicle platoon.An adaptive sliding-mode controller for vehicle is designed to achieve the identification of uncertain coefficients of driving resistance.The designed control algorithm can achieve the tracking for the desired curves of velocity-position with the influence of uncertain driving resistance.In addition,considering the time-varying coefficients of driving resistance,an adaptive sliding-mode is proposed.The results of simulations can demonstrate the effectiveness of proposed algorithms.2.Considering the problem of actuator saturation caused by restriction of the throttle,a signal is proposed to attenuate the integral windup of the control law when actuator saturation occurs.Combining the proposed signal with the basic model,a modified model is constructed.Then,an adaptive sliding-mode control algorithm is designed base on the modified model.Furthermore,leveraging the technique in solving the problem of actuator saturation,the problem of velocity constrains is analyzed and solved.Meanwhile,an adaptive sliding-mode controller is designed.Numerical simulations verify the feasibility and effectiveness of the proposed control method.3.In order to make up the weak and insufficient of model based on Newton's laws in the self-learning for the environment,a RNF NNs-based model is constructed,where the uncertain driving resistance can be approximated by RNF NNs.Next,a Neural-adaptive sliding-mode controller is designed.Then,to further reduce the communication load,an improved control protocol is proposed with only position information,in which a higher-order sliding-mode observer is employed to estimate the other required information(velocity and acceleration).In order to avoid collisions among the vehicles,the string stability of the whole vehicle platoon is proved through stability theorem.Numerical simulation results are provided to verify its effectiveness and advantages over the traditional sliding-mode control method.