Research On Coordination Control Of Multiple Unmanned Underwater Vehicles Under Limited Communication

Unmanned Underwater Vehicle(UUV)is a kind of reused underwater vehicle,which can make decisions independently,recycle and uses repeatedly.UUV is widely applied in military and civil area,such as marine scientific investigation,shipwreck and aircraft inspection,intelligence surveillance,anti-mine and anti-submarine detection.Howerver,an UUV is equipped with limited power supply and sensors,so it cannot meet the requirements of multiple and complex tasks in the harsh marine environment.In recent years,Multiple Unmanned Underwater Vehicles(Multi-UUVs)have been becoming a hot topic,due to its ability to make full use of resources and achievements of the desired goals.Multi-UUVs system is a complex system.Howerver,there are many changllenges for multi-UUVs system to reach control automatically and make decisions independently.Firstly,the overall efficiency of the multi-UUVs system can be reduced and the system can be in the dangerous situation,like conflicts and collisions,if there are no reasonable and efficient coordination control strategies for the multi-UUVs system.Secondly,multi-UUVs system is constrained by liminted communication.Multi-UUVs apply acoustic channel to transmit information among multi-UUVs,which results to the case of liminted communication,such as communication time delays,liminted bandwidth and time varying communication.Thirdly,multi-agents are subject to environment diturbances and uncertainty disturbances.As a consequence,we investigate effective coordination control strategies for multi-UUVs system under limited communication to perform predetermined tasks in this dissertation.According to reaching various tasks for multi-UUVs system,we discuss solution to coordination control of multi-UUVs system from three aspects: leaderless multi-UUVs coordination control algorithms,leader-followings multi-UUVs coordination control algorithms and multiple leaders-followings multi-UUVs coordination control algorithms.Basd on the three aspcects,we also present coordination strategies for multi-UUVS system suffered to limited underwater acoustic communication,envieromental and unmeasurable disturbances.The details are listed as follows.1.Considering about the complex nonlinear and couple model of the UUV,the method of the feedback linearization is used to transform the model into a second-order integral UUV model,in order to apply the advanced linear control method to realize the coordination control of multi-UUVs.Meanwhile,we design reasonable framework of coorperative control to achieve predeterminated tasks for various tasks,which are the framework of leaderless multiUUVs system,the framework of a leader multi-UUVs system and the framework of leaders multi-UUVs system.2.Considering about coordination control of leaderless multi-UUVs system,it is investigated for the coordination method of mulit-UUVs based on no-sampled information and sampled information under limited communication.We propose consensus control method over heterogeneous networks topologies based on no-sampled information and show the sufficient condition to reach consensus control.Then,a novel consensus algorithm is applied to tackle remarkable problems of unmeasurable velocities,the environmental disturbances,and the limited communication condition for the multi-UUVs.we propose a protocol based on the estimation information from the distributed extended state observer(DESO)and demonstrate the multi-UUVs system with the switching directed topologies under the protocol can reach consensus asymptotically.With consideration about the sampled information coordination control,a new sampled-data coordination control algorithm is proposed under position state information relative to neighbor UUVs.Finally,we develop the sufficient condition for the coordination control.3.Concerning about coordination control of leader-followings multi-UUVs system,we address two coordination control problems.Firstly,we establish the coorperation control method for multi-UUVs with unmeasurable disturbances and the time delay under the fixed and switching topologies.For the case of multi-UUVs suffered to unmeasurable disturbances,we design the DESO to estimate the disturbance using the UUV position information relative to its neighbours.In order to solve the problems of unmeasurable disturbance and the case of the limitated communication.DESO is designed to estimate the disturbance and velocity of UUV.Moreover,we show that leader-following multi-UUVs consensus control can be reached for the leader–following UUV system.Secondly,we solve the consensus control problem of leaderfollowing multi-UUVs system suffering the varying communication and time delay under the fixed and switching topologies.For the case of the multi-UUVs with fixed topology,a necessary and sufficient condition of obtaining stability of multi-UUVs system is achieved.For the case of multi-UUVs with switching topology,we develop a sufficient condition with the assumption that leader UUV is globally reachable for the case of multi-UUVs system under the switching topologies.It is proved that multi-UUVs system can reach consensus control and show the estimation of the convergence rate.4.We show the coordination control of multiple leaders-followings multi-UUVs system.Firstly,we discuss the limited conmmunication consensus control of leaders-followings multiUUVs in multi-UUVs system over heterogeneous networks topologies with time delay.Two suitable Lyapunov-Krasovskii functionals is given to obtain sufficient consensus conditions.Then it is proved that system is stochastically stable.Secondly,we present the containment control for multi-UUVs under directed topologies without time delay and with time delay.Two control protocols are designed for multi-UUVs system with time delay and without time delay.Then the sufficient condition is analyzed and obtained.Especially,we show the value of the maximus allowable time delay for the multi-UUVs system with time delay.Finally,we propose the containment control method for multi-UUVs system over heterogeneous topologies with time dealy.Lyapunov-Krasovskii functionals and LMI method are given to obtain sufficient containment control conditions and allowable upper bound of time delay.Meanwhile,the containment control methods for the multiple stationary leaders and dynamic leaders are established.