Event-Triggered Circle Formation Control For Multi-Agent Systems

In practical applications, controllers are in general implemented on digital platforms, and control laws can only be updated at discrete instances of time. Currently, the most common way is periodic sampling, in which controller updates are determined by a constant sampling period. However, the sampling time of periodic sampling system might be conservation in terms of the number of control updates, since the constant sampling period has to guarantee stability in the worst-case scenario. With the progress of technology, agent may equip with an embedded microprocessor, which will be responsible for exchanging information with neighboring agents and actuating the individual agent controller updates. The individual agent has limited energy, which requires the system to reduce energy consumption as much as possible. The controllers update when some certain conditions are satisfied with event-triggered control strategy, and the energy can be saved by this way. Event-triggered multi-agent system not only guarantees the control performance of system to some extent, but also reduces the number of controller updates greatly. Event-triggered formation control for multi-agent systems is studied in this thesis. The main results and contributions of this thesis are as follows.In this thesis, event-triggered circle formation problem is considered firstly for multi-agent system with first-order integrator dynamics. A proper distributed control protocol is designed to form desired circle formations which uses the information of each agent and its neighbors as well as the desired formation information. Both the centralized and decentralized event-triggered control strategies are considered for the circle formation of first-order systems. The circle formation control problem becomes uniform circle formation problem when the desired distance between any two neighboring agents is equal. Therefore, the centralized event-triggered circle formation problem for first-order system is considered first and its uniform circle formation counterpart is considered latter. Further, the decentralized event-triggered uniform circle formation control problem is also investigated in this thesis. Two different kinds of event-trigger conditions are derived through Lyapunov method. Within the proposed strategy and with the event-trigger condition, the circle formation control for first-order system is achieved.Based on the analysis of first-order integrator system, the event-triggered control strategy for the circle formation problem of second-order integrator multi-agent systems is also investigated in this thesis. Similarly, both the centralized and decentralized event-triggered control strategies are considered for second-order systems. Two different kinds of event-trigger conditions corresponding to the centralized and decentralized control scheme are derived through Lyapunov method. The event-triggered circle formation problem of second-order systems is solved under the proposed control law and event-trigger condition.