Research And Control Strategy Of The Ducted-Fan UAV Based On Control Rudder Using Magnus Effect

The ducted-fan UAV has a compact structure. It is more safe between people and the ducted-fan UAV. The ducted-fan UAV has the ability of vertical take-off and landing and hover. Due to the unique properties of the ducted-fan UAV, the research on the ducted-fan UAV will be theoretical value and practical applications. The ducted-fan UAV usually adopts the control vane as the steering engine. This structure has some drawbacks: the control torque is nonlinear. when the adjustment the overall lift will be affected. In order to solve the problems, a ducted fan aerial vehicle model using Magnus effect steering engine is proposed in this paper. This model utilizes a steering engine that comprises four cylinders that are symmetrically installed at the aft inside the duct. Interaction between the spinning cylinder surface and the duct jet flow causes the aerodynamic lift proportional to angular velocity of the cylinder. Therefore, operating range of the aerodynamic lift is guaranteed to be sufficiently wide. This dissertation studies the presented model from the point of computational fluid dynamics(CFD), system dynamics and experiment to analyze and verify the model.In this paper, the ducted fan UAV is analyzed numerically based on the Computational Fluid Dynamics(CFD) by means of sliding mesh technology. The optimization of this ducted fan UAV is conducted based on CFD. The response surface methodology(RSM) and Genetic Algorithm(GA) are adopted in the optimization. The cylinder which is the main component of the steering engine is analyzed by CFD method in 3D geometrical shape. The Magnus effect of the cylinder is clear from the analysis. From the comparison analysis of the cylinder and dumbbell-shape, a more reasonable solution was found. A 3D model of the ducted-fan UAV was established. The forwad flight state and hover state of the ducte-fan UAV were simulated by CFD method. From the analysis results,the generated Magnus force can supply the control torque to stabilize the ducted-fan UAV. The actuator system based on the Magnus effect can decrease the disturbance from the wing and improve the control stability. The cylinder structure, dumbbell structure, the duct, and the position of the steering engine in the duct were optimized based on the CFD method. From the optimization, the structure of the ducted-fan UAV is more reasonable to use the Magnus effect and control the ducted-fan UAV. This provides the basis for the flight of the ducted-fan UAV.Based on the rigid body kinematics, a coordinate system and representation of the attitude angle were established. From the attitude kinematics, linear motion and angular motion of the ducted-fan UAV were obtained. The kinetic equations of the ducted-fan UAV was established inclued the degrees of freedom of the cylinder and propeller. Based on the kutta joukowsky theorem and Magnus effect, the force model of cylinder was established. The whole 11 DOF nonlinear kinetic equations of the ducted-fan UAV was established by Lagrange method. This laid the foundation for the control system design and verify the ducted-fan UAV.From the point of the system theory to verify the ducted-fan UAV, a virtual force(torque) guidance control strategy was proposed based ont the complicated nonlinear kinetic equations of the ducted-fan UAV. The concept of the virtual force(torque) guidance was introduecd. In the design of the control system, the virtual force(torque) guidance method directly used the whole kinetic equations inclued the steering engine and the propeller motion. the proposed method solves the problems as follow: the the steering engine can adjust the aerodynamic lift by itself and the nonlinear couple in the kinetic equations. From the proofs of the system stability, the controller is designed for the ducted-fan UAV. Based on the design of the control system, the simulation is conducted.Due to the kinetic equations which is extremely complex,this will lead to large calculating quantity in the control. From the practical point of view, a layered state-feedback-control algorithm is utilized for performance evaluation. The kinetic equations were linearized with small perturbations, and the decomposed dynamic models were obtained: pitch-forward dynamics, roll-forward dynamics, yaw dynamics, hover dynamics, actuator dynamics. Because of the couple between body dynamics and steering engine, a layed control strategy was proposed. The speed loop and the position loop were analyzed in frequency-domain. The fast response of the speed loop can meet the demands to adjust the attitude control. The position loop is a stable and contractive system. Based on the design of the layed control algorithm, a step response is simulated,and a compensation strategy is designed to solve the fluctuations caused by the the un-modeled coupling factors and yaw motion. In order to verify the design of the control algorithm, three modes which are continuous command mode,step command mode, and free flying mode were simulated. From the results, the control algorithm can make the complicated system stable.In order to verify the theory and method proposed in the paper, the experiments should be conducted. A test platform to test the ducted-fan UAV was established. A controller based on ARM was designed. The measurement module, the Bluetooth module, and the electrical system for the ducted-fan UAV were designed. The program for the attitude control was designed. In order to verify the attitude adjustment ability of the ducted-fan UAV based on the Magnus effect, the test of pitch attitude control was conducted. To verify the validate of control strategy and the fast repsonse of the steering engine, the hover test and angle tracking test were conducted.