Tilt Wing Unmanned Aerial Vehicle Research Articles

Attitude and Cruise Control of a VTOL Tiltwing UAV

This paper presents the mathematical modeling, controller design, and flight-testing of an over-actuated Vertical Take-off and Landing (VTOL) tiltwing Unmanned Aerial Vehicle (UAV). Based on simplified aerodynamics and first-principles, a dynamical model of the UAV is developed which captures key aerodynamic effects including propeller slipstream on the wing and post-stall characteristics of the airfoils. The model-based steady-state flight envelope and the corresponding trim-actuation is analyzed and the overactuation of the UAV solved by optimizing for, e.g., power-optimal trims. The developed control system is composed of two controllers: First, a low-level attitude controller based on dynamic inversion and a daisy-chaining approach to handle allocation of redundant actuators. Secondly, a higher-level cruise controller to track a desired vertical velocity. It is based on a linearization of the system and look-up tables to determine the strong and nonlinear variation of the trims throughout the flight-envelope. We demonstrate the performance of the control-system for all flight phases (hover, transition, cruise) in extensive flight-tests.

Dynamics Modeling and Stability Analysis of Tilt Wing Unmanned Aerial Vehicle During Transition

In the transition mode of quad tilt wing-unmanned aerial vehicle (QTW-UAV), the system stability of UAV will change with the tilt angle changes, which will cause serious head drop down. Meanwhile, with the complex air flow and other disturbances, the system is prone to side bias, frying, stall and other kinetic stability problems, hence the system stability analysis has become an urgent problem to be solved. To solve the stability problem, we need the quantitative criteria of system stability and effective tool of stability analysis, and can improve the stability of the motion control by optimizing the structural parameters of the aircraft. Therefore, based on the design of the mechanical structure, the quantitative relationship between the structure parameters of the aerial vehicle and kinetic stability of the system transition mode is established by the Lyapunov exponent method. In this paper, the dynamic modeling of the position and attitude angle is carried out and the stability of the system is analyzed by Lyapunov exponent, the results show that changing the mechanical structure of the system can improve the flight stability for the system transition mode and lay a theoretical foundation for the system stability analysis. Compared with the Lyapunov direct method, this method can be construct easily, has a simple calculation process and so on. We improve the flight stability by optimizing the structure and the experiment confirms that expanding area can enhance flight stability within limits.

Design and co-simulation of a fuzzy gain-scheduled PID controller based on particle swarm optimization algorithms for a quad tilt wing unmanned aerial vehicle

This paper deals with the systematic design and hardware co-simulation of a fuzzy gain-scheduled proportional–integral–derivative (GS-PID) controller for a quad tilt wing (QTW) type of unmanned aerial vehicles (UAVs) based on different variants of the particle swarm optimization (PSO) algorithm. The fuzzy PID gains scheduling problem for the stabilization of the roll, pitch and yaw dynamics of the QTW vehicle is formulated as a constrained optimization problem and solved thanks to improved PSO algorithms. PSO algorithms with variable inertia weight (PSO-In), PSO with constriction factor (PSO-Co) and PSO with possibility updating strategies (PSO-gbest) are proposed. Such variants of the PSO algorithm aim further to improve the exploration and exploitation capabilities of such a stochastic algorithm as well as its convergence fastness. The robustness of the designed PSO-based fuzzy GS-PID controllers under actuators faults is shown on the non-linear model of the QTW. All optimized fuzzy GS-PID controllers are then co-simulated within a processor-in-the-loop (PIL) framework based on an embedded NI myRIO-1900 board and a host PC. Such a proposed software (SW) and hardware (HW) computer aided design (CAD) platform is based on the Control Design and Simulation (CDSim) module of the LabVIEW environment as well as a set-up Network Streams-based data communication protocol. Demonstrative simulation results are presented, compared and discussed in order to improve the effectiveness of the proposed PSO-based fuzzy gains scheduled PID controllers for the QTW’s attitude flight stabilization.

H∞ Structured Controller Synthesis Applied to Flight Controller of QTW-UAV Using Meta-Heuristic Particle Swarm Optimization

Structured H∞ controller synthesis using particle swarm optimization has been designed in control augmentation system of quad tilt wing unmanned aerial vehicle. It has been aimed to search for the existence of the optimal and practical controller feedback gains within the variations of the relaxation of H∞ constraints for longitudinal motions. The optimization results were achieved in both minimize the maximum real parts of closed-loop eigenvalues and performance indexes in order to verify the validity of the proposed method.

Aerodynamic Design and Characterization of a Quad Tilt-Wing UAV via Wind Tunnel Tests

This paper presents aerodynamic design and characterization of a new quad tilt-wing unmanned aerial vehicle [Sabanci University unmanned aerial vehicle (SUAVI)] through wind tunnel tests and provides experimental data for the design of similar aerial platforms. SUAVI is capable of vertical takeoff and landing (VTOL) and horizontal flight, and it can perform both indoor and outdoor surveillance. Aerodynamic design of the vehicle directly affects its operational performance, including flight stability and flight duration in vertical, transition, and horizontal flight modes. Selection of the propulsion system and determination of the shape of the fuselage and the wings are done in an optimal manner by taking several aerodynamic criteria into account. Flow simulations reveal that the rear wings are affected by the downwash of the front wings. To solve this problem, the rear wings are placed at a higher incidence angle than the front wings. Wind tunnel tests are performed to measure the lift and drag forces and pitching moments for level flight in the entire speed range. Furthermore, the rear and front motor throttle settings and the wing incidence angle combinations for the nominal flight are measured and tabulated. To eliminate undesired spanwise air flows at the wing tips, several winglets with different shapes and sizes are introduced, and the optimum winglet is developed by several simulations and experiments. Some of the results presented in this paper are novel contributions to the literature and can be used in the design of new hybrid unmanned aerial vehicles (UAVs).

Mathematical modeling and vertical flight control of a tilt-wing UAV

This paper presents a mathematical model and vertical flight control algorithms for a new tilt-wing unmanned aerial vehicle (UAV). The vehicle is capable of vertical take-off and landing (VTOL). Due to its tilt-wing structure, it can also fly horizontally. The mathematical model of the vehicle is obtained using Newton-Euler formulation. A gravity compensated PID controller is designed for altitude control, and three PID controllers are designed for attitude stabilization of the vehicle. Performances of these controllers are found to be quite satisfactory as demonstrated by indoor and outdoor flight experiments.

Design and development of a tilt-wing UAV

In this paper, the mechanical and aerodynamic design, carbon composite production, hierarchical control system design and vertical flight tests of a new unmanned aerial vehicle (UAV), which is capable of VTOL (vertical takeoff and landing) like a helicopter and long range horizontal flight like an airplane, are presented. Real flight tests show that the aerial vehicle can successfully operate in VTOL mode. Kalman filtering is employed to obtain accurate roll and pitch angle estimations.

Attitude Control of Quad Rotors QTW-UAV with Tilt Wing Mechanism

In this paper, we propose an autonomous attitude control of a quad tilt wing-unmanned aerial vehicle (QTW-UAV). A QTW-UAV can achieve vertical takeoff and landing; further, hovering flight, which are characteristic of rotary-wing aircraft such as helicopter. And high cruising speeds, which is a characteristic of fixed-wing aircraft, can be also achieved by changing the angle of the rotors and wings by a tilt mechanism. First, we construct an attitude model of the QTW-UAV by using the identification method. We then design the attitude control system with a Kalman filter-based linear quadratic integral (LQI) control method; the experiment results show that a model-based control design is very useful for the autonomous control of a QTW-UAV.