Theory And Simulation On Overall Design And Control System Of The Saucer Ducted Unmanned Aerial Vehicle

The saucer ducted Unmanned Aerial Vehicle (UAV) utilizes the ducted fan as the main lift system, its unique characteristic is the vertical take-off, landing, and hovering. Comparing to the traditional UAV, there still exist many problems on the aerodynamic, structural design and flight control. Especially, the stability of the saucer UAV is undesired, a flight control system is often used to compensate this stability.In this study, the special aerodynamic configuration of the saucer ducted UAV, involving the key technology of designing the vehicle, is systemically studied and simulated in details. We focused on applying the robust control theory to the flight control system, and developed a corresponding hybrid robust controlling method. Finally, this controlling method is applied to designing of the flight control system of saucer UAV. The main results in this study are reported as follows:1?On the basis of the domestic and abroad reports for the overall configuration of the ducted UAV and the design parameters, the overall structure of disc ducted UAV is designed. The vehicle in this study consists of a single rotor with three groups of control vane flake, and the bypass duct structure, the ducted fan provides the main driving force of flight. Due to the imperfect of the recent aerodynamic ducted fan design theory, we integrate the smooth flow theory, the blade element theory and vortex theory of the ducted fan and summarize the computational model, to establish aerodynamic models for hover and forward flight and aerodynamic models of body parts of the disc UAV, then analyze the flight performance. These models may be helpful to solve the complexity of aerodynamic characteristics caused by the low Reynolds number, improve the deficiencies in the aerodynamic design of ducted fan, and provide the supports for the overall design of the saucer ducted UAV.2?A model of whole vehicle dynamics and a model of attitude are built up, the minimum perturbation theory is used to linearize the model of whole vehicle dynamics under the hover style, the equations are decoupled linearly at the operating point, and finally an easy-to-analyze linear model was derived. Due to its special structure, including the light weight and the low moment of inertia, the saucer UAV is easy to be affected by circumstances, otherwise, the unique aerodynamic configuration of saucer UAV leads to the nonlinear strong coupling of its aerodynamic parameters. The above characteristics bring the great difficulty to the design of saucer UAV's flight control system. The dynamics model created according to the above characteristics of the saucer UAV plays a key role in the design of flight control system and sets a fundamental ground for the robust controller.3?A hybrid multi-objective H2/H?Robust control method of uncertain systems is proposed. Based on the H2/H?theory, the robust controller designed via linear matrix inequality method is capable to solve the hybrid control problem in flight control with a variety of performance indicators, and to solve the interference and parameter perturbation problems of uncertain systems. In this paper, we apply those methods to the saucer UAV, and our simulation shows that the hybrid multi-objective H2/H?controller is effective to solve the hybrid control problem in flight control with a variety of performance indicators and has high robust stability and satisfactory dynamic performance. The control method can be applied to UAVs to elevate their levels of anti-interference and maneuverability.4?A design method with hybrid PID/H?Robust control is proposed and applied to the flight control system of saucer UAV. A Hoo robust control design with quadratic stability is used in the inner loop control unit and an interval model is used in the system of aircraft model. This design solves the control problem when the uncertainty of the system matrix and the control matrix parameters exist simultaneously, and ensures the robust stability of design parameters domain in the inner loop to the model's parameter perturbations. By simulating, it is found that, under the hybrid PID/H?robust control, the system could track attitude command excellently, and the overshoot is decreased, which indicates that the controller had strong robustness and the system could effectively inhibit the noise interference.5?In Visual C++development platform, by means of Simulink and FlightGear, a virtual reality flight simulation system is developed. The concept of modular design is adopted by using simulink, the serial communication is applied in Matlab. The real three-dimensional simulation of the UAV is realized by the use of local area network communications and mathematical simulation module communication in order to obtain the mathematical simulation of UAV data. After completed a certain action, according to the given the algorithms, the autopilot issues the steering control instructions, as the feedback signal back to the Simulink model, so that the flight attitude change. The results indicate that, the visual simulation technology used in flight control system can process a variety of flight simulation characteristics, the essential characteristic of the system can be expressed vividly through the virtual prototype. From the real-time simulation results, it is concluded that, the property of real-time meet the requirements, and the result is in agreement with pure digital simulation results, furthermore, it improves the accuracy and reliability of the system.In summary, in this study, the overall design and control system of the saucer ducted UAV are investigated deeply. Considering its special structure of the vehicle, which causes the interference vulnerable to the uncertain interference during the flight, a variety of control methods are used to improve the control theory and the design. Simulation results show that the control system designed in this study can improve and enhance the anti-interference and the aircraft flight maneuverability, and possesses the strong robustness as well as the good noise suppression effect. The theoretical and simulation results obtained in this paper are helpful for the design of the disc UAV.