Adaptive Controller Design for Heterogeneous Cooperative Adaptive Cruise Control System with Uncertain Vehicle Parameters

The implementation of Cooperative Adaptive Cruise Control (CACC) in a vehicle platoon significantly enhances road throughput, traffic safety, and energy efficiency. However, practical applications often involve vehicles with uncertain parameters, as well as a heterogeneous vehicle string. Therefore, instead of relying on linear CACC dynamics, the controller design should consider nonlinear vehicle dynamics. In this paper we propose an adaptive controller that ensures the internal stability of the CACC system without requiring precise vehicle parameter information. The parameter update law for the adaptive controller is derived using Lyapunov theory. To demonstrate the performance of the proposed controller, we conduct simulations comparing the adaptive CACC controller to a standard non-adaptive CACC controller in terms of state tracking and string stability. For this analysis, the adaptive controller presents a reasonable control performance similar to feedback linearizing PD controller with actual vehicle parameters, thus ensuring vehicle platoon string stability for a CACC system with uncertain parameters.