Research On Flight Control Algorithm Of Quadrotor Helicopter

Quadrotor helicopter is a multi-rotor helicopter with simple physical structure,small size,low cost and flexible maneuvering.It is easily controlled and capable of vertical take-off and landing.Compared to the fixed-wing UAV,quadrotor helicopter is more suitable to perform tasks in complex environment with low requirements for take-off and landing conditions.At the same time quadrotor helicopter is a strong coupling,multivariable,non-linear under-actuated system with four control inputs and six state outputs.It is easy to be affected by air flow,un-modeled parts of the system,variation of model parameters,and other physical effects,such as gravity and gyroscopic effects resulting in flight instability.Therefore,it is very important to choose a control algorithm with strong robustness for external disturbances.In this paper,the control of position and attitude of quadrotor helicopter is studied.Firstly,the research background and development status of quadrotor helicopter are summarized.Then the dynamic model of quadrotor helicopter is established.The control algorithms are designed to simulate and experiment in control system.The effectiveness of the proposed control algorithm is verified.The main research contents of this paper are as follows:1.The establishment of quadrotor helicopter dynamics model: The structure and flight principle of quadrotor helicopter are analyzed.The dynamic model of quadrotor helicopter is established using Euler-Lagrangian equations.Finally,Translational equations and rotational equations of quadrotor helicopter are obtained.2.Controller design based on Super-Twisting sliding mode algorithm: The dynamic equation of quadrotor helicopter is divided into full-actuated subsystem and under-actuated subsystem.For the full-actuated subsystem,Super-Twisting sliding mode is used for control.A new global sliding mode control algorithm is used to solve the under-actuated problem in under-actuated subsystem.Finally,the simulation results show that the control algorithm can effectively track the position and attitude of quadrotor helicopter.3.Controller design based on the improved Super-Twisting algorithm: According to the characteristics of the dynamic model of quadrotor helicopter,the control system is divided into inner and outer rings by the structure of sub-loop control.The improved Super-Twisting algorithm is used for position and attitude control.Simulation results show that the control algorithm is better than the Super-Twisting controller.4.Controller design based on adaptive dual layer Super-Twisting algorithm: Aiming at thedynamic model of quadrotor helicopter,an adaptive dual-layer Super-Twisting algorithm is adopted to design the double closed-loop controller.Least squares method is used to solve the under-actuated problem in quadrotor helicopter translation.The two gains in Super-Twisting can be updated in real time,realizing the real-time estimation of system disturbance.The simulation results show the robustness and the effectiveness of the proposed control strategy.5.The hardware and software of quadrotor are designed.The adaptive dual layer Super-Twisting algorithm is used to experiment in actual quadrotor control system.The results show that the designed controller is effective.