Application Of The Networked Predictive Control In 3-DOF Helicopter

Compared with the traditional fixed-wing aeroplane,a helicopter has the advantages of vertical take-off and landing,spot hovering and flexible flight,so it has a bright future in both the military and civil aeras.At the present stage,there are many mature methods for the local control of the helicopter.However,combined with the rapidly changing network technology,the research on the control of the helicopter through the communication network is still l ittle.So the aim of this paper is to apply the network predictive control(NPC)method to the helicopter.In order to cope with the bad effects on the performance of the system caused by network delay and data packet loss in the short time-delay networked control system(NCS),this paper adopted the network predictive control method.The predictive sequence is generated to provide the control parameters and the network delay is compensated.Based on the theoretical analysis,this paper applies the method to the numerical simulation of helicopter system,achieves the flight control of helicopter and verifies the effectiveness of the algorithm.In this paper,the main work and achievements are summarized as follows:(1)This paper introduces the relevant control method of 3-DOF helicopter,the developments of the control method based on NCS and the status of the networked predictive control.(2)To make the research more objective,the basic problems existing in the networked control system,including single packet transmission a nd multi packet transmission,network induced delay,data packet loss,packet timing disorder and network scheduling are introduced and their influences on control system are analyzed.In addition,to provide a theoretical basis for the following research analysis,the basic principle and three features of predictive control,including predictive model,rolling optimization and feedback correction are described.(3)For the 3-DOF helicopter platform produced by Quanser company,the motion equations of each DOF are analyzed,and the state space representation of the system is obtained.Then it is transformed into the state space model of discrete time,the local LQG control law K is solved by using the LMI toolbox,and the pole assignment method is used to obtain the observer gain L,and the local controller is designed.(4)According to the basic idea of predictive control algorithm,combined with the theoretical derivation,the predictive control generator and network delay compensator are designed.And the stability analysis of the closed-loop system whose network delay only exists in the forward channel is done.Then the simulation platform in MATLAB/Simulink environment is set up by using the True Time network toolbox.Based on the platform,each module's function is designed by M-language and the TrueTime package function.(5)Based on the simulation platform,given different control inputs,the response performance of the system is analyzed.Then compare the simulation results with them under the local control,to verify the feasibility of the algorithm.In addition,the numerical simulation is done for different packet loss rate,and the performance of the system is compared.(6)At last,summary of this paper is given,and the future research direction i s also discussed.