ArticlePublisher preview available
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Over the last decade, the share of civilian Unmanned Aerial Vehicles (UAVs) in the general UAV market has steadily increased. These systems are being used more and more for applications ranging from crop monitoring to the tracking air emissions in high-pollution areas. Most civilian applications require UAVs to be low cost, portable, and easily packaged while also having Vertical Take-off and Landing (VTOL) capability. In light of this, the TURAC was designed, a VTOL Tilt Rotor UAV with these capabilities. Mathematical and CFD analyses were performed iteratively in order to optimize the design, but testing in actual conditions were needed. However, as with such an iterative design process, the manufacturing process costs, including different molds for each design, can be exorbitant. In addition, once an imperfection in the design is encountered, making design modifications on the full scale UAV prototype is difficult and expensive. Therefore, a cheap, rapid, and easily reproducible prototyping methodology is essential. In this study, the end result of an iterative design process of TURAC is presented. In addition, a lowcost prototyping methodology is developed and its application is demonstrated in detail. The ground and flight tests are applied on a fully functional prototype and the results are given.
A preview of the PDF is not available
... Additionally, VTOL fixed-wing UAVs with sensors can give real-time, accurate three-dimensional comparative data, critical for effective infrastructure development. As a result, current research has concentrated on fixed-wing VTOL ideas that combine the advantages of fixed-wing and rotary-wing UAVs (Carlson, 2014), , , (Aktas et al., 2016). The predominant imaging sensors such as RGB, spectral, LIDAR, and thermal are mounted on UAV platforms for the advanced applications in sugarcane industries. ...
Article
Full-text available
Recent advancements in the application of unmanned aerial vehicles (UAVs) based remote sensing (RS) in precision agricultural practices have been critical in enhancing crop health and management. UAV-based RS and advanced computational algorithms including Artificial Intelligence (AI), Machine Learning (ML) and Deep Learning (DL), are progressively being applied to make predictions, solve decisions to optimize the production and operation processes in many farming industries such as sugarcane. UAVs with various advanced sensors, including RGB, multispectral, hyperspectral, LIDAR, and thermal cameras, have been used for crop RS applications as they can provide new approaches and research opportunities in precision sugarcane production. This review focuses on the use of UAVs in the sugarcane industry for pest and disease management, yield estimation, phenotypic measurement, soil moisture assessment, and nutritional status evaluation to improve the productivity and environmental sustainability. The goals of this review were to: (1) assemble information on the application of UAVs in the sugarcane industry; and (2) discuss their benefits and limitations in a variety of applications in UAV-based sugarcane cultivation. A literature review was conducted utilizing three bibliographic databases, including Google Scholar, Scopus, Web of Science, and 179 research articles that are relevant to UAV applications in sugarcane and other general information about UAV and sensors collected from the databases mentioned earlier. The study concluded that UAV-based crop RS can be an effective method for sugarcane monitoring and management to improve yield and quality and significantly benefits on social, economic, and environmental aspects. However, UAV-based RS should also consider some of the challenges in sugar industries include technological adaptations, high initial cost, inclement weather, communication failures, policy, and regulations.
... The development of convertible aircraft has been hampered by the complexity involved in the mechanical design. The objective of such prototypes is to obtain an aircraft that can fly as efficiently as an airplane but has the ability to hover as a quadrotor or a helicopter [1][2][3][4][5][6]. ...
Article
Full-text available
This paper proposes a simple flying rotor prototype composed of two small airplanes attached to each other with a rigid rod so that they can rotate around themselves. The prototype is intended to perform hover flights with more autonomy than existing classic helicopters or quad-rotors. Given that the two airplanes can fly apart from each other, the induced flow which normally appears in rotorcrafts will be significantly reduced. The issue that is addressed in the paper is how this flying rotor prototype can be modeled and controlled. A model of the prototype is obtained by computing the kinetic and potential energies and applying the Euler Lagrange equations. Furthermore, in order to simplify the equations, it has been considered that the yaw angular displacement evolves much faster than the other variables. Furthermore a study is presented to virtually create a swashplate which is a central mechanism in helicopters. Such virtual swashplate is created by introducing a sinusoidal control on the airplanes’ elevators. The torque amplitude will be proportional to the sinusoidal amplitude and the direction will be determined by the phase of the sinusoidal. A simple nonlinear control algorithm is proposed and its performance is tested in numerical simulations.
... Over recent years, various kinds of UAV concepts have been developed [1][2][3][4][5][6][7][8][9][10][11][12]. The three most common types of UAVs are the rotary-wing UAVs, the fixed-wing (FW) UAVs, and the mixed UAVs known as hybrid UAVs. ...
Article
Full-text available
In the design stage of an aircraft, structural analyses are commonly employed to test the integrity of the aircraft components to demonstrate the capability of the structural elements to withstand what they are designed for, as well as predict potential failure of the components. This research focused on the structural design and analysis of a high-lift, low Reynolds number airfoil profile, the Selig S1223, under reciprocating inertial force loading, to determine the feasibility of its use in a new reciprocating airfoil (RA) driven VTOL UAV. The material selected for the wing structures including ribs, spars, and skin, was high-strength carbon fiber. The wing was designed in SolidWorks, while finite element analysis was performed with ANSYS mechanical in conjunction with the inertia forces due to the reciprocating motion of the wing and the lift and drag forces that were derived from the aerodynamic wing analyses. The structural stress and strain determined under the loading conditions were satisfactory and the designed wing could sustain the high reciprocating inertia forces in the RA-driven VTOL UAV module. The results of this study indicate that the Selig S1223 airfoil profile, due to its superior performance at low Reynolds numbers, high-lift, and reduced noise characteristics at low angles of attack, combined with the use of the high strength carbon fiber, proves to be an excellent choice for this RA-driven aircraft application.
Article
Full-text available
A Vertical Take-Off and Landing-Plane (VTOL-Plane) is an Unmanned Aerial Vehicle (UAV) that combines multirotor and fixed-wing configurations. It has a good cruise range compared to a VTOL vehicle. Furthermore, it can take-off and land vertically. This technology is ideal for surveillance/monitoring missions and transmitting data in real-time. This study discusses the design of a VTOL-Plane with a preset Design Requirement Objectives (DRO), namely a Maximum Take-Off Weight (MTOW) of 14 kg, a cruise speed of 23 m/s, and a cruising range of 6 h. To maximize the performance, the empennage configurations on the VTOL-Plane varied, and then a Computational Fluid Dynamics (CFD) simulation was carried out. The empennage configurations analyzed were a U-shaped boom, an inverted U-shaped boom, an inverted V-tail boom, and a semi-inverted V-tail boom. The interpreted performance related to the stalling angle, flight efficiency, stability, stall speed, and maneuverability. The relative wind directions toward the longitudinal axis of the UAV, also called the sideslip angle, were varied. The CFD simulation results showed that the empennage configuration of the inverted U-shaped boom is suitable for a surveillance mission. This article also optimized the final empennage design by adding a vertical fin to improve stability.
Chapter
The hybrid-electric technology has great potential in electric aviation. By optimizing power system, hybrid-electric technology can not only improve the efficiency, but also satisfied the requirements of distributed layout to obtain more agile vertical takeoff and landing (VTOL) aircrafts. Combining with flight conditions of VTOL UAV and energy supply characteristics of hybrid-electric systems, this paper establishes a hybrid-electric VTOL UAV model. The impacts of battery initial capacity on the process of vertical takeoff are analyzed that increasing the initial capacity of battery is unfavorable to the agility of the VTOL UAV. On this basis, the typical parameters of hybrid-electric VTOL UAV are calculated by comparing with pure electric VTOL UAVs. It shows that the hybrid-electric VTOL UAV has great advantages in power weight ratio, maximum rate of climb and widest power margin at the takeoff moment. Through emulation program, the minimum fuel consumption distribution at different flight conditions is obtained, and the energy management strategy of the hybrid-electric VTOL UAV in takeoff process is given, which mainly includes the selection of rate of climb and the adjustment of hybridization. The conclusions and analysis methods of this paper can provide a reference for the conceptual design of hybrid-electric aircrafts.
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2022-0879.vid Tilt-rotor vertical takeoff and landing aerial vehicles have been gaining popularity in urban air mobility applications because of their ability in performing both hover and forward flight regimes. This hybrid concept leads energy efficiency which is quite important to obtain a profitable and sustainable operation. However, inherent dynamical nonlinearities of the aerial platform requires adaptation capability of the control systems. In addition, transition flight phase should be planned carefully not only for a profitable operation but also for a safe transition between flight regimes in the urban airspace. In this paper, transition flight phase of a tilt-rotor vertical-takeoff-and-landing unmanned aerial vehicle (UAV) is studied. Low-level flight control systems are designed based on adaptive dynamic inversion methodology to compensate aerodynamic effects during the transition phase. Reinforcement learning method is utilized to provide safety and energy efficiency during the transition flight phase. An actor-critic agent is utilized and trained by using deep deterministic policy gradient algorithm to augment the collective channel of the UAV. This augmentation on the collective input is used to adjust flight path angle of the UAV which results in adjusting the angle of attack when pitch angle is zero. By using this relationship, it is proposed to generate aerodynamic lift force and perform transition flight with minimum altitude change and energy usage. Simulation results show that the agent reduces the collective signal level as the aerodynamic lift force is created in the descent flight phase. This affects overall system efficiency, reduces operational costs and makes the enterprise more profitable.
Chapter
Unmanned aircraft systems (UAS) are an emerging technology with extensive applications in various domains and industries. This technology lends itself greatly to the need in generating high‐quality geospatial data with a high temporal resolution, while also maintaining a high degree of safety. With flexible operations, low implementation costs, and high‐quality data outputs, UAS are ideal tools for urban applications that require rapid mapping, assessment, or management. However, increasingly these applications are facing regulatory challenges from local, state, and national governing bodies. This chapter discusses the opportunities and challenges of UAS for urban remote sensing research. It begins with an introduction to the concept of UAS and some common types of UAS models and cameras onboard, followed by a discussion of a typical UAS data collection procedure including mission planning, flight operations, and data processing. Several urban applications using UAS are discussed, including disaster relief efforts, building inspection, disorder detection, and smart cities construction, along with a case study to demonstrate how UAS can be used for 3D mapping of urban structures. Finally, the major challenges of using UAS for urban studies are discussed, which are related to regulations, operations, and data processing. Recognizing a new frontier of remote sensing applications emerging with UAS platforms, this chapter helps better understand the potential of UAS in urban applications and points out potential future research directions .
Conference Paper
View Video Presentation: https://doi.org/10.2514/6.2021-2415.vid A verification and validation assessment of an open-source framework, the Stanford University Aerospace Vehicle Environment (SUAVE), and its individual modules, for the multidisciplinary design and optimization of small-scale, supersonic, unmanned aerial vehicles (UAVs) was performed. Multi-fidelity modules for aerodynamics, stability, propulsion, and weight estimation are compared to experimental wind-tunnel data, flight data, and commercial supplier data for supersonic aircraft, high-speed UAVs, and turbojet propulsion systems. An improved weight estimation module is proposed for small-scale, supersonic UAVs. Academic designs for supersonic UAVs are analyzed and compared to a conceptual design from the University of Calgary, for a variety of metrics. These UAV designs are compared at a range of scales, and the impact of different conceptual design methods on their performance is compared. Design improvements, and potential pitfalls related to conceptual design accuracy are discussed.
Article
Full-text available
Testing of untethered subscale models, often referred to as subscale flight testing, has traditionally had a relatively minor, yet relevant use in aeronautical research and development. As recent advances in electronics, rapid prototyping and unmanned-vehicle technologies expand its capabilities and lower its cost, this experimental method is seeing growing interest across academia and the industry. However, subscale models cannot meet all similarity conditions required for simulating full-scale flight. This leads to a variety of approaches to scaling and to other alternative applications. Through a literature review and analysis of different scaling strategies, this study presents an overall picture of how subscale flight testing has been used in recent years and synthesises its main issues and practical limitations. Results show that, while the estimation of full-scale characteristics is still an interesting application within certain flight conditions, subscale models are progressively taking a broader role as low-cost technology-testing platforms with relaxed similarity constraints. Different approaches to tackle the identified practical challenges, implemented both by the authors and by other organisations, are discussed and evaluated through flight experiments.
Article
Full-text available
Distributed electric propulsion technology brings new ideas to the design of unmanned aerial vehicle(UAV), such as improving aerodynamic efficiency and propulsive efficiency, and new concept of vertical/short takeoff and landing configurations. However, compared with conventional UAV, the propulsion system of distributed electric propulsion UAV is more complex, which brings difficulties and challenges to the design of distributed electric propulsion UAV. Based on its special aerodynamic/propulsive coupling characteristics, this paper studies the design method and process of primary parameters of distributed electric propulsion UAV. A short takeoff and landing UAV with distributed electric propulsion system is taken as an example for the conceptual design and primary parameter design, and the influence of design parameters on the takeoff mass and endurance is analyzed. Finally, the validity of the established design method is verified by the flight test of the prototype. Results indicate that the distributed electric propulsion system accounts for more than 20% of the takeoff mass; the electric ducted fan efficiency, mass specific power of the motor, mass specific power of the electronic speed controller and the resistivity of power wires are the most significant design parameters that affect the performance of the UAV; with the improvement of technologies, the takeoff mass is expected to be reduced by more than 20%, and the endurance is expected to be increased by more than three times.
Conference Paper
Full-text available
This paper presents a formal intent based Flight Management System (FMS) hardware and functional structure utilising multi-level autonomy modes. The novel advanced capabilities added to the UAV autopilots are envisioned to meet the requirements of the future flight operations of the UAVs integrated into national airspace. The proposed FMS structure integrates new functionalities such as a) formal intent based information exchange and collaborative tactical planning utilising air-to-air and air-to-ground data links and, b) decentralised immediate sense-and-avoid. The collaborative nominal operation mode enables the ground operator to build “shared intelligence” with the UAV through the intent sharing. In this mode, the intent sharing process benefits from the advantages of formal intent languages at different levels of abstraction and data-links. The air-to-ground data link allows the ground operator to update/modify/re-plan the flight intent (FI) of the UAV(s) in any phase of the operation according to evolving situations through ground station. The air-to-air intent sharing also continues between the surrounding aircraft through the aircraft intent (AI) (“machine-to-machine” level) communication which makes unmanned systems to be visible. The sense-and-avoid mode, the FMS recursively computes and observes the probabilities of potential immediate collisions with the other aircraft and terrain. Whenever the immediate response needs, the FMS executes the generated 3D avoidance maneuver. For technology demonstration purposes, an experimental FMS hardware has been deployed in a quadrotor UAV, and a ground operator station with GUI has been designed enabling envisioned operational experiments.
Article
Full-text available
For the last four decades Unmanned Air Vehicles (UAVs) have been extensively used for military operations that include tracking, surveillance, active engagement with weapons and airborne data acquisition. UAVs are also in demand commercially due to their advantages in comparison to manned vehicles. These advantages include lower manufacturing and operating costs, flexibility in configuration depending on customer request and not risking the pilot on demanding missions. Even though civilian UAVs currently constitute 3 % of the UAV market, it is estimated that their numbers will reach up to 10 % of the UAV market within the next 5 years. Most of the civilian UAV applications require UAVs that are capable of doing a wide range of different and complementary operations within a composite mission. These operations include taking off and landing from limited runway space, while traversing the operation region in considerable cruise speed for mobile tracking applications. This is in addition to being able traverse in low cruise speeds or being able to hover for stationary measurement and tracking. All of these complementary and but different operational capabilities point to a hybrid unmanned vehicle concept, namely the Vertical Take-Off and Landing (VTOL) UAVs. In addition, the desired UAV system needs to be cost-efficient while providing easy payload conversion for different civilian applications. In this paper, we review the preliminary design process of such a capable civilian UAV system, namely the TURAC VTOL UAV. TURAC UAV is aimed to have both vertical take-off and landing and Conventional Take-off and Landing (CTOL) capability. TURAC interchangeable payload pod and detachable wing (with potential different size variants) provides capability to perform different mission types, including long endurance and high cruise speed operations. In addition, the TURAC concept is to have two different variants. The TURAC A variant is an eco-friendly and low-noise fully electrical platform which includes 2 tilt electric motors in the front, and a fixed electric motor and ducted fan in the rear, where as the TURAC B variant is envisioned to use high energy density fuel cells for extended hovering time. In this paper, we provide the TURAC UAV’s iterative design and trade-off studies which also include detailed aerodynamic and structural configuration analysis. For the aerodynamic analysis, an in-house software including graphical user interface has been developed to calculate the aerodynamic forces and moments by using the Vortex Lattice Method (VLM). Computational Fluid Dynamics (CFD) studies are performed to determine the aerodynamic effects for various configurations For structural analysis, a Finite Element Model (FEM) of the TURAC has been prepared and its modal analysis is carried out. Maximum displacements and maximal principal stresses are calculated and used for streamlining a weight efficient fuselage design. Prototypes have been built to show success of the design at both hover and forward flight regime. In this paper, we also provide the flight management and autopilot architecture of the TURAC. The testing of the controller performance has been initiated with the prototype of TURAC. Current work focuses on the building of the full fight test prototype of the TURAC UAV and aerodynamic modeling of the transition flight.
Article
Full-text available
Nowadays, mini Unmanned Aerial Vehicles (UAVs) are utilized in a wide range of reconnaissance and surveillance missions with an ever increasing need for endurance and range. Thus, a slight improvement on these two primary performance parameters is considered as a competitive advantage. In this work, a multi-functional tailless UAV concept and its design process is presented. In comparison to existing conventional UAV designs, the concept is shown to have superior aerodynamic and flight performance characteristics. In addition the detachable wing and body concept provides the much needed flexibility and multi-functionality for using the UAV for a range of operation concepts, in which each concept requires different payloads of distinct weight and size.
Article
Full-text available
Design of an electric propulsion system for an unmanned aerial vehicle incorporates various disciplines such as the propeller's aerodynamic and structural properties, characteristics of the electric system, and characteristics of the vehicle itself. This makes the design of this propulsion system a multidisciplinary design optimization task. Although the present propeller model is based on previous derivations that are described very briefly, new models of the electric motor and battery pack, which are based on examining existing products on the market, are described in more detail. The propeller model and a model of the electric system, together with various optimization schemes, are used to design optimal propulsion systems for a mini unmanned aerial vehicle for various goals and under various constraints. Important design trends are presented, discussed, and explained. Although the first part of the investigation is based on typical characteristics of the electric system, the second part includes a sensitivity study of the influence of variations of these characteristics on the optimal system design.
Conference Paper
Full-text available
In this work, we present a micro-avionics system structured around the controller area network (CAN) bus data backbone. The system is designed to be cross-compatible across our experimental mini-helicopters and ground vehicles, and it is tailored to allow autonomous navigation and control for a variety of different research test cases. The expandable architecture deploys a hybrid selection of COTS Motorola (MPC555) and Arm processor boards (LPC2294), each with different operating systems and coding techniques (such as rapid algorithmic prototyping using automatic code generation via Matlab/Real Time Workshop Embedded Target). The micro-avionics system employs a complete sensor suite that provides real-time position, orientation and associated time-rate information. As a part of the on-going fleet autonomy experiments, we present the design of a novel wireless SmartCan node. This wireless node allows seamless CAN Bus access of low-level sensor and operational data of other vehicles within close proximity.
Conference Paper
Full-text available
Aricopter is a COTS micro-helicopter heavily modified for research on embedded flight and vision controls, and distributed autonomy. In this work, we present an overview of the exciting development process of the flight hardware, the micro-avionics system, and the off-board vision implementations.
Article
The rapidly-expanding aerospace industry is a prime developer and user of advanced metallic and composite materials in its many products. This book concentrates on the manufacturing technology necessary to fabricate and assemble these materials into useful and effective structural components. Detailed chapters are dedicated to each key metal or alloy used in the industry, including aluminum, magnesium, beryllium, titanium, high strength steels, and superalloys. In addition the book deals with composites, adhesive bonding and presents the essentials of structural assembly. This book will be an important resource for all those involved in aerospace design and construction, materials science and engineering, as well as for metallurgists and those working in related sectors such as the automotive and mass transport industries. Flake Campbell Jr has over thirty seven years experience in the aerospace industry and is currently Senior Technical Fellow at the Boeing Phantom Works in Missouri, USA. *All major aerospace structural materials covered: metals and composites *Focus on details of manufacture and use *Author has huge experience in aerospace industry *A must-have book for materials engineers, design and structural engineers, metallurgical engineers and manufacturers for the aerospace industry.