Academic literature on the topic 'Fixed-wing UAV guidance'

The purpose of this paper is to develop a fixed-wing aircraft that has the abilities of both vertical take-off (VTOL) and a fixed-wing aircraft. To achieve this goal, a prototype of a fixed-wing gyroplane with two propellers is developed and a rotor can maneuver like a drone and also has the ability of vertical take-off and landing similar to a helicopter. This study provides guidance, navigation, and control algorithm for the gyrocopter. Firstly, this study describes the dynamics of the fixed-wing aircraft and its control inputs, i.e., throttle, blade pitch, and thrust vectors. Secondly, the inflow velocity, the forces acting on the rotor blade, and the factors affecting the rotor speed are analyzed. Afterward, the mathematical models of the rotor, dual engines, wings, and vertical and horizontal tails are presented. Later, the flight control strategy using a global processing system (GPS) module is designed. The parameters that are examined are attitude, speed, altitude, turn, and take-off control. Lastly, hardware in the loop (HWIL) based simulations proves the effectiveness and robustness of the navigation guidance and control mechanism. The simulations confirm that the proposed novel mechanism is robust and satisfies mission requirements. The gyrocopter remains stable during the whole flight and maneuvers the designated path efficiently.

This article considers the problem of trajectory tracking control for a micro fixed-wing unmanned air vehicle (UAV). With Bank-to-Turn (BTT) method to manage lateral deviation control of UAV, this paper discusses the outer loop guidance system, which separates the vehicle guidance problems into lateral control loop and longitudinal control loop. Based on the kinematic model of the coordinated turning of UAV, the aircraft can track a pre-specified flight path with desired error range. Flight test results on a fixed-wing UAV have indicated that the trajectory tracking control law is quite effective.

A fault-tolerant control scheme for the autopilot of the small fixed-wing UAV is designed and tested by the actual flight experiments. The small fixed-wing UAV called Xiang Fei is developed independently by Nanjing University of Aeronautics and Astronautics. The flight control system is designed based on an open-source autopilot (Pixhawk). Real-time kinematic (RTK) GPS is introduced due to its high accuracy. Some modifications on the longitudinal and lateral guidance laws are achieved to improve the flight control performance. Moreover, a data fusion based fault-tolerant control scheme is integrated in altitude control and speed control for altitude sensor failure and airspeed sensor failure, which are the common problems for small fixed-wing UAV. Finally, the real flight experiments are implemented to test the fault-tolerant control based autopilot of UAV. Real flight test results are given and analyzed in detail, which show that the fixed-wing UAV can track the desired altitude and speed commands during the whole flight process including takeoff, climbing, cruising, gliding, landing, and wave-off by the fault-tolerant control based autopilot.

Abstract In this paper a single camera vision guidance system for fixed wing UAV is developed. This system searches for and identifies a target object with known colour and shape from images captured by an onboard camera. HSV colour space and moment invariants are utilised to describe the colour and shape features of the target object. Position, area and rotation angle of the target object in the image plane are collected. This information is then processed by the Extended Kalman Filter to estimate the relative positions and attitudes of the UAV. The vision guidance system guides the UAV towards the target object automatically based on these estimated states by using a proportional controller. A Senior Telemaster aircraft model kit installed with an onboard camera and computer is used for flight test. The target object for the flight test is a white flag with a red cross. Flight simulations and flight tests results are presented in this paper, showing that the vision guidance system can recognise the target object and guide the UAV effectively.

From the cost-effective viewpoint of low cost Bank-to-Turn (BTT) Unmanned Air Vehicles (UAV) and target drone, a low cost flight control system, with the fewest number of sensors, is studied in this paper for the fixed-wing UAV. The structure of the control system is described which is able to estimate necessary information to provide stabilization and guidance for a small fixed wing BTT UAV. The practical flight control system structure and control law for roll hold loop, altitude hold loop, trajectory tracking loop are designed based on the sensor configuration with only a MEMS rate gyro, a MEMS pressure sensor and global positioning system (GPS) receiver only. A prototype low cost autopilot is trial-produced to control a typical UAV. The Experimental results show the effectiveness of navigation and control methods of f the proposed methodology.

Abstract This paper presents the design and implementation of a vision-based automatic guidance system on a fixed-wing unmanned aerial vehicle (UAV). The system utilises a low-cost ordinary video camera and simple but efficient image processing techniques widely used in computer-vision technology. The paper focuses on the identification and extraction of geographical tracks such as rivers, coastlines, and roads from real-time aerial images. The image processing algorithm primarily uses colour properties to isolate the geographical track of interest from its background. Hough transform is eventually used to curve-fit the profile of the track which yields a reference line on the image plane. A guidance algorithm is then derived based on this information. In order to test the vision-based automatic guidance system in the laboratory without actually flying the UAV, a hardware-in-the-loop simulation system is developed. Description regarding the system and significant simulation result are presented in the paper. Finally, an actual test flight where the UAV successfully follows a stretch of a river under automatic vision-based guidance is also presented and discussed.

In recent years, inspired by technological progress and the outstanding performance of Unmanned Aerial Vehicles (UAVs) in several local wars, the UAV industry has witnessed explosive development, widely used in communication relay, logistics, surveying and mapping, patrol, surveillance, and other fields. Vertical Take-Off and Landing fixed-wing UAV has both the advantages of vertical take-off and landing of rotorcraft and the advantages of long endurance of fixed-wing UAV, which broadened its application field and is the most popular UAV at present. Recently, fixed-wing UAV failure analysis highlights that cruise engine shutdown is the most common reason for emergency landing, which is also a governing factor for Vertical Take-Off and Landing (VTOL) fixed-wing UAV failures. Nevertheless, the emergency landing trajectory of the latter UAV type after engine shutdown is different from that of the conventional fixed-wing UAVs due to the VTOL power system. Hence, spurred by the requirement of a safe emergency landing trajectory for VTOL fixed-wing UAVs, this paper develops an architecture capable of safe emergency landing for such platforms. The suggested method develops a particle dynamics model of the VTOL UAV and analyzes its aerodynamic characteristics utilizing Computational Fluid Dynamics (CFD) results. The UAV’s trajectory is divided into three parts for enhanced planning. For the guidance stage, the initial position and heading angle are arbitrary. Hence, the Dubins shortest cross-range and the fastest descent trajectory are adopted to steer the UAV above the landing window quickly. The spiral stage comprises a conical and cylindrical part combined with a spiral descent trajectory of variable radius for energy management and landing course alignment. Given the limited energy storage of VTOL power systems, the landing stage exploits an optimal control trajectory problem solved by a Gaussian pseudospectral method, involving trajectory conventional landing planning, unpowered landing, distance optimal landing, and wind-resistant landing. All trajectories meet the dynamics constraints, terminal constraints, and sliding performance constraints and cover both 2-dimensional and 3-dimensional trajectories. A large number of simulation experiments demonstrate that the proposed trajectories manage broad applicability and strong feasibility for VTOL fixed-wing UAVs.

Abstract For the fixed-wing UAV control system, the lateral path-following system is an important part, which ensures that the UAV flies stably in accordance with the predetermined route within a certain height. For the lateral path following of UAV based on nonlinear model predictive control, the model of the lateral kinematics of the fixed-wing UAV is established first, and then the path-following problem of UAV at a constant height is considered. The objective function with constraints based on the NMPC is established, and finally the nonlinear optimization algorithm is used to minimize the designed objective function. The optimal control quantity in the rolling interval is obtained. Matlab is used to simulate the designed controller and compare it with the commonly used L1 guidance law, and the results of the simulation demonstrate that the NMPC has superior control leverage.

This paper covers exploratory efforts that attempt to address limitations and restrictions in the operating envelope of UAVs, and proposes a conceptual solution to the problem. UAVs, like aircraft, can be categorized into two main types: fixed wing and rotary wing. A fixed wing UAV flies using wings that generate lift caused by the vehicle’s forward airspeed and the shape of the wings. The greatest advantage of fixed wing UAVs obtained from utilizing aerodynamic lift is its long range and high endurance performance. However, this primary advantage comes from the fact that most fixed wing UAVs have wings that are of a high aspect ratio, which becomes a liability in confined operating conditions. An autonomous aerial hard docking system is proposed as a system that manages to enable different UAV platforms to have operational envelopes which far exceed the operational envelopes of the constituent UAV platforms. The paper outlines necessary subsystems that need to exist for autonomous aerial hard docking capability. It presents practical requirements of the various constituent subsystems, namely the guidance and navigation subsystem, the grasping subsystem and the damping subsystem. For each of the subsystems, the challenges which have to be overcome to ensure the effectiveness of the complete system are examined. It further elaborates the testing, investigation and development steps that need to be implemented to realize this capability. It ends by elaborating on the work already underway and future development plans. Note that this paper presents a conceptual logical and architectural solution, and as such detailed analysis findings are inappropriate and premature.