Controller Synthesis with a Cone Complementarity Linearization Algorithm for CACC System Under Time-varying Delay

Cooperative Adaptive Cruise Control (CACC) is an intelligent vehicle technology that enables vehicle follow-up in a small inter-vehicle distance. Stability is the main property of the CACC system that prevents any signal fluctuations throughout the vehicle string. In CACC system, time delay has a negative impact on string stability. The reason is that constant and varying time delays are unavoidable in real traffic. Here, controller gains should be synthesized under constant and time-varying communication delays to satisfy ${\mathcal{L}_2}$-string stability conditions (in the Lyapunov sense). Contrary to previously studied convex method, controller gains are now synthesized with iterative nonlinear minimization algorithm and Cone Complementarity Linearization (CCL) method. The results show that the new CCL approach provides more accurate and practical stability bounds. Hence, this shows the potential of CCL to perform more sensitive analyses. The results obtained are evaluated by simulations with the heterogeneous CACC system.