Online Feedforward/Feedback Structure Adaptation for Heterogeneous CACC Strings

Cooperative Adaptive Cruise Control has been extensively studied in recent years, however most of efforts have been oriented to homogeneous strings control. When a heterogeneous string is formed, the differences between vehicles dynamics introduce disturbances in the closed loop system affecting the string stability. This paper presents an online CACC feedforward adaptation with a fractional-order feedback controller for stable heterogeneous strings of vehicles. A particle filter algorithm is employed to perform an online parameter identification over the preceding vehicle longitudinal model, allowing further adaptation of the control structure. Simulations demonstrate the advantages over conventional homogeneous structures as well as system's capability to both enhance stability and guarantee string stability regardless the vehicles distribution.