| Highway platooning of vehicles has been identified as a promising framework in developing intelligent transportation systems. By autonomous or semi-autonomous vehicle control and inter-vehicle coordination, an appropriately managed platoon can potentially offer enhanced safety, improved highway utility, increased fuel economy, and reduced emission. This thesis is focused on quantitative characterization of impact of communication information structures and contents on platoon safety. By comparing different information structures which combine front sensors, rear sensors, and wireless communication channels, and different information contents such as distances, speeds, and drivers' actions, we reveal a number of intrinsic relationships between vehicle coordination and communications in platoons. Typical communication standards and related communication latency and package loss are used as benchmark cases in our study. These findings provide useful guidelines for information harmonization module (IHM) design in sensor selections, communication resource allocations, and vehicle coordination. Two new weighted multi-information structure control and information data rate control are proposed. Both control methods have been validated by experimental simulation and finite element analysis, and also show a surprising improvement of communication resources usage with data rate control. The results for the proposed module are new in the literature for vehicle platoon control. A new method is introduced to enhance feedback robustness against communication gain uncertainties. The method employs a fundamental property in stochastic differential equations to add a scaled stochastic dither under which tolerable gain uncertainties can be much enlarged, beyond the traditional deterministic optimal gain margin. Algorithms, stability, convergence, and robustness are presented for first-order systems. Extension to higher-dimensional systems is further discussed. Simulation results are used to illustrate the merits of this methodology. |
