This thesis contains recent results on the problem of coordinating a group of vehicles having nonlinear dynamics. The motivation driving this work is the development of control laws that steer individual members of a formation by solving the path- and/or speed assignments, such that the desired group behavior emerges. In this thesis I have attempted to achieve these goals and I have designed various control systems. For the solutions I used the publications of engineers well known around the world and the results of the past few decades’ control theory. The main contribution of this thesis can be grouped into three control designs.
The first design proposes a hierarchical formation stabilization method for road vehicles and marine supply vessels. I designed a potencial function based high-level controller which is interconnected with a dynamic inversion based low-level controller. The low-level controller linearizes the original vehicle dynamics, so that the stability of the formation could be easily guaranteed by applying a passivity based external feedback.
The second design describes the robust output maneuvering problem for passivity-based synchronized path-following in case of marine supply vessels. In this thesis I present two designs, a cascaded interconnection where a cooperating system provides synchronized path parameters as inputs to the individual path-following system, and a feedback interconnection which, moreover, employs the path error information in the synchronization loop and more robust to vehicle and communication failures. I have developed the controllers using a robust recursive technique called backstepping and I used passivity as a design tool for group coordination.
In the third design a scheme for formation modeling and control, inspired by analitical mechanics of multi-body systems and Lagrangian multipliers, is proposed for road and marine vehicles. In this approach to formation control, various formation behaviors are determined by imposing constraint functions.
For testing these methods I have used the MATLAB/Simulink™ software family and I have created a graphical user interface in which the various aspects of the implemented control system can be observed.