| Vehicle platoon control has received substantial attention in recent years due to the serious problems of road congestion,traffic accidents and environmental pollution.For the physical limitations of vehicle systems and distributed characteristic,distributed model predictive control(DMPC)algorithm has become the main strategy to tackle with vehicle platoon control problems.From the points of development and practical requirement of vehicle platoon control,the external disturbances,multiple constraints,communication delays and other issues are considered in vehicle platoon control system.The corresponding DMPC algorithms are proposed,which can make vehicles drive in the desired platoon stably and effectively.Numerical simulations and experiments verify the effectiveness of the proposed control method.The main contributions of this dissertation are as follows:1.Considering the nonlinear dynamic model of vehicles,a dual-mode DMPC algorithm is proposed for vehicle platoon control.In details,vehicle states are divided into two parts by a designed invariant set(outside invariant set and inside invariant set).When the vehicle states are outside the invariant set,the control input is calculated by online receding horizon optimization;otherwise,a simple state feedback control law is applied.The dual-mode mechanism can not only reduce the calculation burden,but also save the communication resources to some extent.2.Considering the problems of control input saturation and external disturbances in the vehicle platoon driving process,a robust DMPC algorithm is proposed for vehicle platoon control.In the optimization control model of distributed vehicles,the control constraint and robust constraint can effectively control the vehicle platoon control system and ensure the stability of the vehicle platoon system under bounded disturbances.On this basis,the feasibility of the algorithm and the stability of the system are fully analyzed and verified by simulation results.3.Considering the problems of actual physical constraints of vehicles and communication delays between vehicles,a delay-involved constrained DMPC algorithm is proposed for vehicle platoon control.In practice,these physical constraints contain vehicle control input,velocity,acceleration and acceleration jerk.Meanwhile,the DMPC algorithm combining with the waiting mechanism is applied to deal with the communication delays effectively.By ensuring the feasibility and stability of the algorithm,the upper bound value of the delays is obtained,the vehicles can achieve stable platoon under the bounded communication delays meanwhile satisfying the multiple constraints.4.The DMPC algorithm is verified by simulating experiments with multiple Turtle Bot3 mobile robots substituting vehicles.The Robot Operating System(ROS)is used to realize the driving,communication and distributed model predictive controllers designing for Turtle Bot3 mobile robots with certain authenticity and expandability.In the experiment,multiple mobile robots can achieve the desired formation under the proposed control algorithm.The experimental results verify the feasibility of the algorithm and the stability of the platoon system. |
