Modeling And Verification Of A Ducted Coaxial Rotor Aircraft

Rotorcraft is always the hotspot in aviation field for its perfect performance in hovering and low-speed flight. Generally, rotorcraft is of considerable size for torque balancing. In recent years, a new kind of aircraft called ducted coaxial rotor aircraft is showing up prominently, with both the advantage of rotorcraft and much smaller scale. Modeling and verification of this widely watched aircraft is the mainly work of the paper.At first, this paper designs the model with traditional theories of rotorcraft, for example, the momentum theory and the blade element theory. And data from the flight experiment is used to correct the error of these theories. This paper builds a nonlinear simulation model with Matlab/Simulink and trims the nonlinear model in some conditions, then gets the linear model in the form of state-space equation. Designing the flight control law and doing some simulation.Secondly, this paper designs a flight control system for the study object. The design covers avionics system design, flight control software design and ground control system design. This paper chooses motors, electric adjustors and cells based on the estimation result of the required power and chooses sensors like IMU, GPS and Altimeter considering the need of the signal’s precision. The flight control software uses PID method as its core algorithm and accomplishes the stability augmentation control loop and the attitude control loop. The ground control system includes communication equipments, operation computer and the software, and the software is most important. The ground control software is based on C# visual language. Modularized design idea and multi-thread technique are adopted. The ground design accomplishes data recording, data and curve displaying, electronic map displaying and so on.Then, this paper tests the flight control system and tunes the PID parameters. Testing and tuning are accomplished in several experiments, just like static debugging, mooring test and flight test. In the experiment process, each step is progressive to guarantee the UAV is stable enough for the next step.At last, this paper gathers and processes data in and after flight experiments, then accomplishes the work of verification. Verification is done from the aspects of trim verification, control parameters verification and simulation verification.