Fleet Cooperative Adaptive Cruise Control And Analysis

In order to improve the adverse effects of the self-imposed defects of the wireless communication system on the cooperative adaptive cruise control and to study the performance improvement of the cooperative adaptive cruise control,this paper establishes a queue cooperative adaptive cruise control(CACC)controller based on the model predictive control(MPC)algorithm,and proposes a corresponding switching strategy for the communication delay packet loss and communication interruption problems.The performance and effectiveness of the established queue controller and the proposed switching strategy are simulated and verified by the joint Simulink and Car Sim simulation platform.First,the overall control framework of cooperative adaptive cruise control is established as a hierarchical control structure,where the upper controller is built based on the model predictive control algorithm and the lower controller is based on the fuzzy PID control algorithm.Next,the drive and brake models of the vehicle are established;the switching strategy between drive and brake is designed by fitting a function with a fifth polynomial numerator and a fourth polynomial denominator;the shift logic strategy is established based on the throttle opening and engine speed;and the vehicle longitudinal lower-level controller is established based on the fuzzy PID control algorithm.The final simulation results show that the lower level controller has excellent control performance.Then,the vehicle model and queueing model are established according to the spacing strategy and communication topology,and the upper layer controller is designed based on the model predictive control algorithm,and the following,safety,comfort and fuel economy are expressed as physical expressions and the cost function is established and optimized;the physical limit of the vehicle is used as the constraint for the optimal solution in the optimization;in order to cope with the communication packet loss and communication interruption to achieve In order to cope with communication packet loss and communication interruption to achieve better queueing control effect,this paper improves a packet loss compensation strategy to cope with packet loss and a transition mode for cooperative adaptive cruise control system to degrade to adaptive cruise control system smoothly to cope with communication interruption.Finally,the simulation analysis of CACC queue is summarized based on Simulink and Car Sim joint simulation platform,and four simulation conditions are designed for acceleration-even speed-deceleration condition,rapid acceleration start-high speed emergency braking condition,communication packet loss delay condition and communication interruption condition.The results show that the improved packet loss compensation strategy to cope with packet loss has good information compensation effect,and the transition mode can make the cooperative adaptive cruise control system degrade into adaptive cruise control system more smoothly.And after the analysis of the communication delay condition,it can be concluded that the communication delay has a large impact on the spacing error and has a very obvious negative impact on the performance of the cooperative adaptive cruise control queue,and if we want to improve the overall following performance and stability of the CACC vehicle queue,reducing the communication delay is a very effective way.