Longitudinal and Lateral Coordinated Control of a Platoon Based on Improved Intelligent Driver Model

In order to study the influence of road geometric parameters such as curve, super-elevation and slope on the longitudinal and lateral coordinated control of intelligent and connected platoon, a cooperative control system using the longitudinal velocity of the vehicle as the coupled variable of the longitudinal and lateral motion is designed. The upper acceleration model of longitudinal car-following control adopted the improved intelligent driver model to reflect the influence of road geometric parameters on the car-following behavior. Combined with the inverse longitudinal dynamics model to realize the speed following of the guided vehicle. The lateral trajectory control adopted the single-point preview model in which the preview distance follows the coupling speed change to realize the trajectory tracking of the guided vehicle, and the sliding mode controller is designed to improve trajectory tracking accuracy. The Carsim/Simulink co-simulation platform was built, then acceleration-deceleration, double shifting line and ramp conditions were adopted to verify longitudinal, lateral and cooperative control performance of the cooperative control system. The results show that (1) The longitudinal and lateral cooperative control system has good longitudinal car-following performance and high lateral trajectory tracking accuracy, it maintains high tracking accuracy for the speed and acceleration of the guided vehicle. The distance between vehicles is positively correlated with speed changes, and the inter-vehicle distance tends to be stable when the speed is stable. Meanwhile, the steering angle of the control system has a high consistency with the Carsim's built-in model, and the steering is smooth. The lateral offset is less than 0.2 meters, and the control system with sliding mode control has higher trajectory tracking accuracy. (2) The intelligent and connected platoon composed of the coordinated control system based on the IIDM has more obvious longitudinal and lateral response to the road geometric parameters than the platoon of the IDM. The specific performance is that the deceleration behavior is more obvious, the inter-vehicle distance increase by 0.55 meters, the steering angle reduce and average lateral offsets reduce by 2.51×10^-6 meters, which is more conducive to the overall safety of the platoon.