Landing Of Unmanned Aerial Vehicle Research Articles

A Brief Survey on Bio-inspired Algorithms for Autonomous Landing∗∗The work is supported under IISc-DRDO collaborative project TR-DRDO-PAME-2015-05. The authors acknowledge Mr Ashutosh Simha, SERC, IISc for technical inputs and DRDO-FIST for the infrastructure provided.

The paper briefly introduces a few bio-inspired algorithms which can be applied to autonomous landing for Unmanned Aerial Vehicles (UAVs). A number of vision based data acquisition methodologies used for UAV navigation and guidance are described. Monocular camera based vision data can be used to extract plethora of information about the dynamics of a target plane in landing problems and also about the pose of the camera itself. Some recent, developments in the areas of autonomous landing and perching based on vision data from monocular camera are introduced. Some possible relevant extensions are also provided. (C) 2016, IFAC (International Federation of Automatic Control) Hosting by Elsevier Ltd. All rights reserved.

Control System Design of a Vertical Take-off and Landing Fixed-Wing UAV

Abstract: In this study, design and implementation of control system of a vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) with level flight capability is considered. The platform structure includes both multirotor and fixed-wing (FW) conventional aircraft control surfaces; therefore named as VTOL-FW. The proposed method includes implementation of multirotor and airplane controllers and design of an algorithm to switch between them in achieving transitions between VTOL and FW flight modes. Thus, VTOL-FW UAV’s flight characteristics are expected to be improved by enabling agile maneuvers, increasing survivability and exploiting full flight envelope capabilities.

An Integration Method of Inertial Navigation System and Three-Beam Lidar for the Precision Landing

To ensure the high accuracy, independence, and reliability of the measurement system in the unmanned aerial vehicle (UAV) landing process, an integration method of inertial navigation system (INS) and the three-beam Lidar is proposed. The three beams of Lidar are, respectively, regarded as an independent sensor to integrate with INS according to the conception of multisensor fusion. Simultaneously, the fault-detection and reconstruction method is adopted to enhance the reliability and fault resistance. First the integration method is described. Then the strapdown inertial navigation system (SINS) error model is introduced and the measurement model of SINS/Lidar integrated navigation is deduced under Lidar reference coordinate. The fault-detection and reconstruction method is introduced. Finally, numerical simulation and vehicle test are carried out to demonstrate the validity and utility of the proposed method. The results indicate that the integration can obtain high precision navigation information and the system can effectively distinguish the faults and accomplish the reconstruction to guarantee the normal navigation when one or two beams of the Lidar malfunction.

An Actuator Fault Detection and Isolation method design for Planar Vertical Take-off and Landing Unmanned Aerial Vehicle modelled as a qLPV system

This paper presents the design of a tracking controller and a fault detection and isolation system for a Planar Vertical Take-off and Landing (PVTOL) Unmanned Aerial Vehicle (UAV) under actuator faults. In order to control the PVTOL, the dynamic system is divided into three subsystems driven by the rotational, the altitude, and the position dynamics. The altitude and position subsystems are based on qLPV model while the rotational subsystem is linear. A linear observer applied to the rotational subsystem is considered to detect actuator faults, which can occur as failures (loss of a propeller or a motor) or partial faults (degradation). Furthermore, fault isolation is done by measuring roll velocity due to the actuator fault. In all cases, sufficient conditions for the existence of the observer and the controllers are given in terms of linear matrix inequalities (LMIs). Finally, simulations (on the nonlinear model) are done in order to illustrate the effectiveness of the proposed methodology.

Определение конструктивных параметров беспилотного летательного аппарата с изменяемой в полете структурой с использованием математического моделирования

A review of existing approaches to reduce the distance run and a horizontal speed landing unmanned aerial vehicle. In this paper we investigate the dynamics of movement of the unmanned aerial vehicle with a constant angle of wing sweep. Balancing control method used to commit the landing maneuver. Such a control process is carried out by displacing part of the machine, called the load platform relative to the main portion of the apparatus. For the mathematical description of the selected control principle uses dynamic equations of motion of the system of rigid body. Mathematical models of the aerodynamic force coefficients are approximated by trigonometric functions, for use in a wide range of angles of attack. The implementation of the mathematical model of the motion is carried out by means of the library SimMechanics Matlab / Simulink software. Against the background of the overall driving dynamics further discusses the use wing warping to increase the power of resistance in order to reduce the horizontal landing speed. We consider constructive solutions drive wing warping, stand design parameters influencing the driving dynamics of an unmanned aircraft as a whole. It is proposed to consider the following structure of a mathematical model consisting of two parts: a general driving dynamics system of rigid body and the internal dynamics of the drive. This approach allows you to evaluate the impact on the overall dynamics of the movement of unmanned aircraft in flight with a variable structure of the internal dynamics of the drive. In this paper we performed numerical simulations and discuss the results characterizing the operation of the drive. We study kinematic parameters of the drive: the angle of rotation, rotational speed and angular acceleration, as well as the source specified by the control law. The results suggest the feasibility of the proposed approach.

Conceptual Study of a Smart Docking System for VTOL-UAV

AbstractThis paper describes the conceptual design of a vertical takeoff and landing unmanned aerial vehicle (VTOL-UAV), mountable on an unmanned ground vehicle (UGV) for their combined operation as a team. The design aims to compensate for the weak points of each platform by providing carrying, launching, recovery, and recharging capabilities for the mounted VTOL-UAV through the host UGV. A sphere-shaped mechanical docking interface between the UAV–UGV is proposed to allow flexible and accurate positioning, and its operational concept with a coaxial rotorcraft UAV is suggested as one particular instance. A vision-based, target-tracking method to enhance the precision landing performance also was investigated and tested with a ground-based experimental setup.

Inspection of Pole-Like Structures Using a Visual-Inertial Aided VTOL Platform with Shared Autonomy.

This paper presents an algorithm and a system for vertical infrastructure inspection using a vertical take-off and landing (VTOL) unmanned aerial vehicle and shared autonomy. Inspecting vertical structures such as light and power distribution poles is a difficult task that is time-consuming, dangerous and expensive. Recently, micro VTOL platforms (i.e., quad-, hexa- and octa-rotors) have been rapidly gaining interest in research, military and even public domains. The unmanned, low-cost and VTOL properties of these platforms make them ideal for situations where inspection would otherwise be time-consuming and/or hazardous to humans. There are, however, challenges involved with developing such an inspection system, for example flying in close proximity to a target while maintaining a fixed stand-off distance from it, being immune to wind gusts and exchanging useful information with the remote user. To overcome these challenges, we require accurate and high-update rate state estimation and high performance controllers to be implemented onboard the vehicle. Ease of control and a live video feed are required for the human operator. We demonstrate a VTOL platform that can operate at close-quarters, whilst maintaining a safe stand-off distance and rejecting environmental disturbances. Two approaches are presented: Position-Based Visual Servoing (PBVS) using an Extended Kalman Filter (EKF) and estimator-free Image-Based Visual Servoing (IBVS). Both use monocular visual, inertia, and sonar data, allowing the approaches to be applied for indoor or GPS-impaired environments. We extensively compare the performances of PBVS and IBVS in terms of accuracy, robustness and computational costs. Results from simulations and indoor/outdoor (day and night) flight experiments demonstrate the system is able to successfully inspect and circumnavigate a vertical pole.

Visual 3D Model-based Tracking toward Autonomous Live Sports Broadcasting using a VTOL Unmanned Aerial Vehicle in GPS-Impaired Environments

This paper presents a novel approach for autonomous live sports broadcasting using visual 3D model-based tracking and a vertical take-off and landing (VTOL) unmanned aerial vehicle (UAV) such as a quadcopter or hexacopter in GPS-impaired environments. To achieve this level of autonomy, position estimation is essential and is a highly challenging problem using a monocular camera due to the scale ambiguity. In this paper, we track a tennis court, that is standard in dimension, using a moving edge-based tracker, and recover the scale with the prior knowledge of the fixed playing field. Experimental results are demonstrated in 3 different environments including static scenes, real broadcast video, and indoor flying. We also evaluate the proposed approach with the ground truth provided by a motion capture system and achieve a position estimation with less than 0:02m standard deviation in the error.

수직이착륙 무인항공기 자동 착륙을 위한 영상기반 항법

Pose estimation is an important operation for many vision tasks. This paper presents a method of estimating the camera pose, using a known landmark for the purpose of autonomous vertical takeoff and landing(VTOL) unmanned aerial vehicle(UAV) landing. The proposed method uses a distinctive methodology to solve the pose estimation problem. We propose to combine extrinsic parameters from known and unknown 3-D(three-dimensional) feature points, and inertial estimation of camera 6-DOF(Degree Of Freedom) into one linear inhomogeneous equation. This allows us to use singular value decomposition(SVD) to neatly solve the given optimization problem. We present experimental results that demonstrate the ability of the proposed method to estimate camera 6DOF with the ease of implementation.

Parachute systems for unmanned aerial vehicles

The types and characteristics of parachute systems, which can be used for the safe landing of unmanned aerial vehicles in an emergency or safe landing parachute after the flight mission.

Trajectory tracking of vertical take-off and landing unmanned aerial vehicles based on disturbance rejection control

We investigate the trajectory tracking problem of vertical take-off and landing (VTOL) unmanned aerial vehicles (UAV), and propose a practical disturbance rejection control strategy. Firstly, the nonlinear error model is established completely by the modified Rodrigues parameters, while considering dynamics of the servo actuators. Then, a hierarchical control scheme is applied to design the translational and rotational controllers based on the time-scale property of each subsystem, respectively. And the linear extended state observer and auxiliary observer are used to deal with the uncertainties and saturation. At last, global stability of the closed-loop system is analyzed based on the singular perturbation theory. Simulation results show the effectiveness of the proposed control strategy.

Image-based tracking control of VTOL unmanned aerial vehicles

This paper addresses the image-based control problem of vertical take-off and landing (VTOL) unmanned aerial vehicles (UAVs). Specifically, we propose a control scheme allowing the aircraft to track a moving target captured by an onboard camera where the orientation and angular velocity of the vehicle are assumed available for feedback. The proposed approach relies on appropriate image features, defined based on perspective image moments along with a useful projection, and the design of a bounded adaptive translational controller without linear velocity measurements in the presence of external disturbances. Estimates of the target’s acceleration and the disturbances as well as some auxiliary variables are used to simplify the control design and guarantee the stability of the overall closed loop system. Simulation examples are provided to show the effectiveness of the proposed theoretical results.

Design of Four-Rotor Unmanned Aircraft Control System Based on ARM

As a new type of vertical take-off and landing unmanned aerial vehicles, four-rotor unmanned aircraft has strong load capacity, simple structure, flexible operation Characteristics, so it is the preferred method of execution the air, and is widely used in military and civil field. Based on four-rotor aircraft structure and movement theory, this paper designs the aircaft control system based on ARM. Based on upper machine, the design of PID control algorithm was tested in this paper. From the results, the stability of the controller is good, and its speed control is superior to the single closed-loop.

LSD Based Pose and Position Estimation for UAV Landing

Currently, there has been growing interest in unmanned aerial vehicle (UAV) during the landing. With the widespread use of the UAVs, a more precise estimation on pose and position in the process of landing is required to support the higher-level applications. In this paper, the estimation of pose and position based on the line segment detection (LSD) is proposed. By applying a vision camera, a landmark is detected using the effective LSD algorithm. Then a line-based vision model is built to calculate the pose and position of the UAV. Experimental results show that the state solutions of the proposed method are effective with different shape of landmarks, and the accuracy is minute-level in pose angle error and centimeter-level in position error.

Altitude and Attitude Control of a Trirotor UAV

This paper outlines the dynamic modelling as well as the attitude and altitude control of a rotary based unmanned aerial vehicle (UAV). A multirotor vertical take-off and landing (VTOL) UAVs, namely Trirotor aircraft is investigated. In essence the the trirotor model consists of three DC motors equipped with three fixed pitch angle rotors without the aid of a swashplate. The mathematical modelling of this multirotor is governed by the Newton-Euler formulation. A classical control algorithm viz. heuristic (Proportional-Integral-Derivative) PID tuning was adopted in the attitude and altitude control of this particular multirotor configuration. It was established from the Simulink simulations that, a PD controller was suffice to control the attitude whilst PID was apt for controlling the altitude of this form of multirotor.

A Neuro-Adaptive Augmented Dynamic Inversion Design for Robust Auto-Landing

A neuro-adaptive augmented nonlinear dynamic inversion approach is proposed in this paper for robust automatic landing of unmanned aerial vehicles. Following the philosophy of indirect adaptive control, a set of linear in weight neural networks are used to rapidly learn the unknown part of the system model online. This continuously updated model is simultaneously used in a dynamic inversion framework that results in an adaptive controller which is quite robust to the modeling inaccuracies (i.e. parametric uncertainties of the model) and external wind shear disturbance. The training rule of neural networks is obtained from Lyapunov stability theory, where a Sobolev norm based Lyapunov function is chosen. This leads to 'directional learning', resulting in fast learning without exciting too much of transient oscillations. Robust performance of this neuro-adaptive augmented nonlinear controller is successfully validated through six degree-of-freedom simulation studies.

Optical-Flow Based Strategies for Landing VTOL UAVs in Cluttered Environments

This paper considers the question of landing an Unmanned Aerial Vehicles (UAV) using a single monocular camera as the primary exteroceptive sensing modality. The proposed control law is based on tracking a single point feature, representing the desired landing point on a ground plane, along with optical flow computed over the full image. The bearing of the desired landing point is used as a driving term to force convergence, while the optical flow is used to provide a damping force that guarantees both obstacle avoidance as well as damping the convergence of the vehicle to the ground plane ensuring a soft touchdown. A detailed analysis of the system closed-loop dynamics is undertaken and the response of the system is verified in simulation.

Pitch Loop Control of a VTOL UAV Using Fractional Order Controller

Pitch loop control is the fundamental tuning step for vertical takeoff and landing (VTOL) unmanned aerial vehicles (UAVs), and has significant impact on the flight. In this paper, a fractional order strategy is designed to control the pitch loop of a VTOL UAV. First, an auto-regressive with exogenous input (ARX) model is acquired and converted to a first-order plus time delay (FOPTD) model. Next, based on the FOPTD model, a fractional order [proportional integral] (FO[PI]) controller is designed. Then, an integer order PI controller based on the modified Ziegler-Nichols (MZNs) tuning rule and a general integer order proportional integral derivative (PID) controller are also designed for comparison following three design specifications. Simulation results have shown that the proposed fractional order controller outperforms both the MZNs PI controller and the integer order PID controller in terms of robustness and disturbance rejection. At last, ARX model based system identification of AggieAir VTOL platform is achieved with experimental flight data.

Tip Clearance Investigation of a Ducted Fan Used in VTOL Unmanned Aerial Vehicles—Part I: Baseline Experiments and Computational Validation

Ducted fans that are popular choices in vertical take-off and landing (VTOL) unmanned aerial vehicles (UAV) offer a higher static thrust/power ratio for a given diameter than open propellers. Although ducted fans provide high performance in many VTOL applications, there are still unresolved problems associated with these systems. Fan rotor tip leakage flow is a significant source of aerodynamic loss for ducted fan VTOL UAVs and adversely affects the general aerodynamic performance of these vehicles. The present study utilized experimental and computational techniques in a 559 mm diameter ducted fan test system that has been custom designed and manufactured. The experimental investigation consisted of total pressure measurements using Kiel total pressure probes and real time six-component force and torque measurements. The computational technique used in this study included a 3D Reynolds-averaged Navier–Stokes (RANS) based computational fluid dynamics model of the ducted fan test system. Reynolds-averaged Navier–Stokes simulations of the flow around the rotor blades and duct geometry in the rotating frame of reference provided a comprehensive description of the tip leakage and passage flow. The experimental and computational analysis performed for various tip clearances were utilized in understanding the effect of the tip leakage flow on the aerodynamic performance of ducted fans used in VTOL UAVs. The aerodynamic measurements and results of the RANS simulations showed good agreement, especially near the tip region.

A camera calibration method for large field optical measurement

A camera calibration method is presented for large field optical measurement, where the camera is close to the ground and the control points can only be located close to the ground, too. In such conditions, the camera's optical center and the control points are approximately coplanar. Only a single image of these control points captured by the camera in measurement state is used in the method. Neither to distribute the control points in space rationally nor to calibrate the camera's intrinsic parameters in laboratory in advance is needed. By the presented method, the camera's principal point position, focal length, radial and transverse tangency lens distortion coefficients, and the camera's position and attitude parameters can be estimated precisely. Then the calibration results can be used for precise large field optical measurement in the conditions that the camera's longitudinal tangency lens distortion can be neglected or the objects’ movement field is close to the ground, which is usually factual in practical applications. The presented camera calibration method has been successfully used in applications, such as automatic landing of UAV (Unmanned Aerial Vehicle) based on optical measurement guidance, to calibrate the cameras precisely.