Optimization And Simulation Of CACC System Based On Multi Objective Decision Algorithm And PID Control

The Cooperative Adaptive Cruise Control(CACC for short) system is one of the most important parts of ITS. Based on the adaptive cruise control,through the internet of vehicles,the vehicles share the state information to the vicinal vehicles which can makes the vehicle not only response the car directed before it but also response all the vehicles in front of it in a certain range.The CACC system is more security, efficient and comfort than conventional ACC system.In this paper, we design the longitudinal CACC system based on multi objective decision algorithm and PID control, the system is divided into decision making layer and control layer. First of all, we collection of the vehicle and the vehicle around information, through the decision making layer of multi objective decision algorithm we get an ideal acceleration then put the acceleration to the control layer, through the PID control algorithm we get the vehicle control information, then the control information input to the vehicle module, finally realizes the control of the vehicle. In the analysis of the acceleration decision algorithm based on multi objective, this paper analyzes three indicators which influence of car, security, efficiency and stability in the analysis of safety distance we improved the original safety distance formula joined the acceleration parameters, makes the safety distance calculation more in line with the actual situation, and the stability of the safe distance of the improved algorithm is verified. In CACC system control layer design, combined with the actual situation of auto control, first of all, the PID controller is optimized the input, then use two PID controller, control of automobile throttle and brake pressure respectively, and finally in the output stage, according to the actual situation we filter the output, through simulation experiment, we put the ideal acceleration compare the actual acceleration,we verified the effectiveness of the control layer.Using carsim and simulink simulation, set up the vehicle parameters of kinematics and dynamics in carsim, then output the related data of carsim into the simulink model, through model we calculate the amount of control then back to the carsim, achieve the control of the vehicle state. In five car model, we compare CACC system with the conventional ACC system under the five common working condition,by contrast, we verified the CACC system is more security, efficient and comfort than conventional ACC system.