Cloud-based Connected Vehicle Control under Time-Varying Delay: Stability Analysis and Controller Synthesis

The emergence of connected vehicles and cloud-based control technologies promise great benefits to transportation systems. For practical application, time-varying delay from vehicular communication and edge/cloud computing has a critical influence on the vehicle control performance. To address this problem, this paper focuses on the stability analysis and controller design for connected vehicles under time-varying delay at the cloud-based control architecture. Particularly, connected car-following control and connected path-following control are under consideration as specific examples, where the cloud-unit assigns the control commands. A general switched system model has been established for connected vehicle control, where time-varying delay is imposed on partial system states. For stability analysis, an improved stability condition is proposed for the switched system under general case of time-varying delay with less conservative property compared with existing work. Further, based on Markov process assumption on time-varying delay, a quantitative stability evaluation method is introduced. Then, an $\mathcal {H}_\infty$ controller design method has been presented, which incorporates multiple requirements, including stability under delay, control error for safety, and control rapidity. Extensive numerical simulations validate the performance of the proposed control method at multiple traffic scenarios.