Research On Formation Control Problems Of Second-order Multi-agent Systems

In the past decades,distributed cooperative control of multi-agent systems has attracted increasing interests.This is partly due to its wide applications to service robots,exploration of hazardous environments,military surveillance and reconnaissance,search and rescue in disaster sites,spacecraft formation flying,etc.Formation control,which is one of the most actively studied topics within the realm of multi-agent systems,the application of formation control spans various fields,such as cooperative surveillance,source seeking,unmanned aerial vehicle,and so on.In addition,as a matter of fact,second-order multi-agent system is a kind of very extensive agent system,such as unmanned aerial vehicles,underwater vehicles and so on.Now,second-order multi-agent systems is an important model of formation control.Therefore,research on formation control problems for second-order multi-agent systems has broad application prospect and great values both on theory and practice.Considering the future trend of broader networks and increased quantity of agents,as well as physical,safety or technological constraints,this thesis studies the formation control problem of second-order multi-agent system based on event-triggering mechanism and the formation control problem of second-order multi-agent system subjected to input saturation.and several formation control protocols for linear/nonlinear second-order multi-agent systems are proposed.More specifically the frame and innovation of this thesis are given as follows:1.Event-triggering formation control for second-order multi-agent systems with sampled position data.The problem of event-triggering formation control for second-order multi-agent with sampled position data is discussed.Firstly,two types of distributed event-triggering formation control strategies based on the position sampled data are proposed to solve the formation control problems.These novel formation control strategies allow the event-triggering conditions to be intermittently examined at random sampling instants where the data transmission is driven by an event-triggering control protocol.Under this framework,both time-invariant and time-varying formation controls are considered.Then,based on the algebraic graph theory and matrix theory,some sufficient conditions are given to ensure that the second-order multi-agent systems achieve the specified formation shape that belongs to the feasible formation sets.Finally,simulation results are provided to show the effectiveness of the theoretical analysis.2.Event-triggering formation tracking for second-order multiagent systems subjected to input saturation.The formation tracking control protocols are designed for second-order multi-agent systems,in which each agent is subject to input saturation.First,by using the low-gain state feedback technique,it is proved that second-order multi-agent system subjected to input saturation achieves the specified semi-global formation tracking if the formation tracking feasibility condition holds.Then,in order to reduce the communication load,an event-triggering control strategy is applied to solving the considered system.It is shown that the specified semi-global formation tracking is guaranteed,and Zeno behavior can be avoided.Finally,several simulation examples are given to confirm the theoretical results.3.Time-varying formation tracking for second-order multi-agent systems subjected to switching topology and input saturation.The problem of time-varying formation tracking is addressed for a kind of secondorder multi-agent systems with a switching topology,in which the dynamics of agents are modeled by double integrators and harmonic oscillators respectively.The control input of each agent is subject to saturation.First,depending on the low-gain state feedback technique,an algorithm is designed to solve semiglobal time-varying formation tracking problem,where feasibility condition of formation tracking is introduced.Then,by utilizing the Lyapunov function and low-gain feedback theory,it is proved that second-order multi-agent system with a switching topology achieves the specified semi-global time-varying formation tracking if some sufficient conditions hold.Further,as an extension,jointly connected switching topology is considered,and the corresponding formationtracking problem is also explored.Subsequently,several simulation examples is worked out for illustration.4.Formation Control with Multiple Leaders via Event-triggering Transmission Strategy.Event-triggering formation control with multiple leaders in second-order nonlinear multi-agent systems is investigated in this paper.This proposed formation control strategy allows the event-triggering condition to be intermittently examined at sampling instants,where the data transmission is driven by an event-triggering control protocol.Based on this strategy,two different formation control protocols are presented.Then,some sufficient conditions are given to ensure the second-order nonlinear multi-agent systems converge to the desired formation shape.Finally,examples are given to show the effectiveness of theoretical results.