Research On Consensus Formation Control Method Of Multiple Quadrotors

Quadrotor unmanned Aerial Vehicle(UAV)has the advantages of simple structure,light weight,strong flexibility and can take off and land vertically and hover at a fixed point.It has been widely used in environmental monitoring,target search,accident rescue and other fields.The dynamic model of quadrotor is an underactuated nonlinear system with strong coupling and it is susceptible to external disturbances during flight.Under certain complicated circumstances,we always need to use several quadrotors to accomplish a task cooperatively for the limited payload,sensor,cruising ability of a single quadrotor.The quadrotor unmanned aerial vehicles are considered as the research object and the control of a single quadrotor as well as multiple quadrotors are analyzed in this paper.The main contents are provided as follows:Firstly,the structure and motion control method of the quadrotor are introduced.The quadrotor is regarded as a rigid body and the appropriate coordinate system is selected.The force and moment are analyzed to establish the kinematics and dynamics models of the quadrotor.The quadrotor model is divided into position subsystem and attitude subsystem.Considering the external disturbance and modeling error of the quadrotor during flight,disturbance observers and controllers are designed for the position subsystem and attitude subsystem respectively to realize the stable tracking of the desired reference trajectory for a single quadrotor and the influence of compound disturbance on the stability of the aircraft is reduced at the same time.Secondly,a distributed finite-time formation tracking control strategy based on state observer is proposed to solve the problem that only part of quadrotors can obtain the state information of leader quadrotor directly.Considering that not all quadrotors can communicate with the leader and obtain its state information under the condition of using distributed formation control strategy.The distributed finite time state observer is designed for each quadrotor to estimate the relative state information of itself and the leader quadrotor.Then,a finite-time controller is designed based on the results of the state observer and the stability analysis verifies the effectiveness of the proposed formation control strategy.From the simulation results,it can be seen that the quadrotors can form and maintain the desired formation in finite time.Finally,considering that the upper bound of the compound disturbance of the quadrotor may not be obtained in advance,a formation control strategy based on adaptive observer is proposed.The adaptive disturbance observer is designed to estimate the compound disturbance which is compensated in the design of the control law in real time.The adaptive state observer is designed to estimate the relative state information between the followers and the leader quadrotor.The derivative of the desired attitude angle is difficult to calculate due to the influence of external disturbance on virtual control input and the chattering of the sliding mode control method.Then,the third-order integral filter is designed to estimate the desired attitude angle and its derivative to reduce the influence of external disturbance and chattering on the stability of the system.