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Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu 2019 Laboratoire des Signaux et Syst`emes (L2S) CentraleSup´elec-CNRS-Universit´e Paris Sud, 3 rue Joliot- Curie 91192 Gif-sur-Yvette cedex, France.

Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, Chi Jin, Keqin Gu, Islam Boussaada, Silviu-Iulian Niculescu

SIUE Faculty Research, Scholarship, and Creative Activity

This paper presents a systematic method to analyse the stability of systems with single delay in which the coefficient polynomials of the characteristic equation depend on the delay. Such systems often arise in, for example, life science and engineering systems. A method to analyze such systems was presented by Beretta and Kuang in a 2002 paper, but with some very restrictive assumptions. This work extends their results to the general case with the exception of some degenerate cases. It is found that a much richer behavior is possible when the restrictive assumptions are removed. The interval of interest for the ...


End To End Satellite Servicing And Space Debris Management, Aman Chandra, Himangshu Kalita, Roberto Furfaro, Jekan Thanga 2019 Univ. of Arizona

End To End Satellite Servicing And Space Debris Management, Aman Chandra, Himangshu Kalita, Roberto Furfaro, Jekan Thanga

Space Traffic Management Conference

There is growing demand for satellite swarms and constellations for global positioning, remote sensing and relay communication in higher LEO orbits. This will result in many obsolete, damaged and abandoned satellites that will remain on-orbit beyond 25 years. These abandoned satellites and space debris maybe economically valuable orbital real-estate and resources that can be reused, repaired or upgraded for future use. Space traffic management is critical to repair damaged satellites, divert satellites into warehouse orbits and effectively deorbit satellites and space debris that are beyond repair and salvage. Current methods for on-orbit capture, servicing and repair require a large service ...


Low Level Turbulence Detection For Airports, Anthony O' Connor, Derek Kearney 2019 Dublin Institute of Technology

Low Level Turbulence Detection For Airports, Anthony O' Connor, Derek Kearney

International Journal of Aviation, Aeronautics, and Aerospace

Abstract—— Low level wind shear and turbulence present a serious safety risk to aircraft during the approach, landing and take-off phases. Despite many advances in on-board and ground based warning systems. Wind shear remains a formidable force that coupled with a microburst can overpower any aircraft. Aviation reports have concluded that pilots need to have improved information in relation to tailwinds, wind shear and wind variations on approach and during the landing phases. Low level wind shear continues to cause disruption, delays and contribute to aircraft crashes. As recently as 2016, two Boeing aircraft crashed while attempting a Go-around manoeuver ...


Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins 2019 Embry-Riddle Aeronautical University

Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins

International Journal of Aviation, Aeronautics, and Aerospace

The Federal Aviation Administration (FAA) has put forth a set of regulations (Part 107) that govern small unmanned aerial system (sUAS) operations. These regulations restrict unmanned aircraft (UA) from flying over people and their operation to within visual line of sight (VLOS). However, as new applications for unmanned aerial systems (UAS) are discovered, their capabilities improve, and regulations evolve, there is an increasing desire to undertake urban operations, such as urban air mobility, package delivery, infrastructure inspection, and surveillance. This built environment poses new weather hazards that include enhanced wind shear and turbulence. The smaller physical dimensions, lower mass and ...


Optimal Attitude Control Of A Two-Cubesat Virtual Telescope In A Highly Elliptical Orbit, reza pirayeshshirazinezhad 2018 University of New Mexico - Main Campus

Optimal Attitude Control Of A Two-Cubesat Virtual Telescope In A Highly Elliptical Orbit, Reza Pirayeshshirazinezhad

Shared Knowledge Conference

This paper investigates a novel approach for attitude control of 2 satellites acting as a virtual telescope. The Virtual Telescope for X-ray Observations (VTXO) is a mission exploiting 2 6U-CubeSats operating in a precision formation. The goal of the VTXO project is to develop a space-based, X-ray imaging telescope with high angular resolution precision. In this scheme, one CubeSat carries a diffractive lens and the other one carries an imaging device to support a focal length of 100 m. In this mission, the attitude control algorithms are required to keep the two spacecraft in alignment with the Crab Nebula observations ...


Pulsed Fiber Optics Lasers As Highly Sensitive Sensors, Hanieh Afkhamiardakani 2018 University of New Mexico

Pulsed Fiber Optics Lasers As Highly Sensitive Sensors, Hanieh Afkhamiardakani

Shared Knowledge Conference

An interferometer or resonator is a device in which optical beams of specific frequencies circulate with minimal losses. These losses are completely compensated by the gain inside a laser resonator. A small perturbation introduced inside the laser can affect its frequency, which in turns becomes a metric of that perturbation. The perturbation is usually caused by an electric or magnetic field, rotation, acceleration, nonlinear index of refraction etc. Tiny changes of optical frequency are monitored by superimposing the laser field and a reference field (from the same laser) on a detector. This technique requires creating a laser in which two ...


Quadrotor Swarm Arena (Quasar) Development Of A Swarm Control Testbed, Shane T. Stebler, William MacKunis 2018 Embry-Riddle Aeronautical University

Quadrotor Swarm Arena (Quasar) Development Of A Swarm Control Testbed, Shane T. Stebler, William Mackunis

Beyond: Undergraduate Research Journal

Swarm control systems are increasingly popular in the robotics industry and academia due to their many potential applications. The goal of the Quadrotor Swarm Arena (QuaSAr) project is to construct a quadrotor swarm control testbed to provide researchers with the tools needed to experimentally investigate this emerging science. This testbed is equipped with a motion capture system, test control station, and numerous quadrotor UAVs. MATLAB-Simulink is utilized for control law development, data processing, and test control. This configuration allows researchers to test developing control law in a 'plug and play' manner as control development and test control are all completed ...


Design And Performance Estimation Of A Low-Reynolds Number Unmanned Aircraft System, Sean Lauderdale King 2018 Louisiana State University and Agricultural and Mechanical College

Design And Performance Estimation Of A Low-Reynolds Number Unmanned Aircraft System, Sean Lauderdale King

LSU Master's Theses

The purpose of this thesis is to conceptually design a fixed-wing unmanned aircraft systems (UAS) with a higher flight-time and top stable speed than comparable systems. The vehicle adheres to specifications derived from the client, the market, and the Federal Aviation Administration (FAA). To broadly meet these requirements, the vehicle must fly for a minimum of three hours, return to the original flight path quickly if perturbed, and must be hand-launched. The vehicle designed must also have a large potential center of gravity movement to allow for customization of the planform and client customization.

An iterative design process was used ...


Static Performance Results Of Propellers Used On Nano, Micro, And Mini Quadrotors, Robert W. Deters, D. Dantsker, Stefan Kleinke, Narcrisha Norman, Michael S. Selig 2018 Embry-Riddle Aeronautical University

Static Performance Results Of Propellers Used On Nano, Micro, And Mini Quadrotors, Robert W. Deters, D. Dantsker, Stefan Kleinke, Narcrisha Norman, Michael S. Selig

Publications

An increase in the number of small quadrotors has created the interest in having performance data on the propellers used by these aircraft. With an aircraft size less than 5 in and propellers diameters less than 3 in, these quadrotors are typically referred to mini, micro, or nano by hobbyists and manufacturers. The size of the propellers used on these aircraft operate at low Reynolds numbers that are typically less than 50,000 for diameters up to 3 in and less than 20,000 for diameters up to 2 in. Static performance testing of the propellers used on 11 small ...


Validation And Verification Flight Tests Of Fixed-Wing Collaborative Uass With High Speeds And High Inertias, A Ram (Bella) Kim 2018 Iowa State University

Validation And Verification Flight Tests Of Fixed-Wing Collaborative Uass With High Speeds And High Inertias, A Ram (Bella) Kim

A Ram (Bella) Kim

The research objective for this work is to validate and verify guidance, navigation, and control algorithms that are designed for fixed-wing collaborative unmanned aerial systems (UASs) in unstructured environments. A biologically-inspired swarm control theory provides a framework to distribute sensor payloads between several smaller and less complex agents that have local interactions. Controller design and flight testing of large UASs with high speeds and high inertias holding a formation in a dynamically changing environment and in the presence of external disturbances is complex and requires advanced planning and safety measures. Verification and validation flight tests were conducted using a fixed-wing ...


Book Review: Fundamentals Of International Aviation, Alan Bender 2018 Embry-Riddle Aeronautical University - Worldwide

Book Review: Fundamentals Of International Aviation, Alan Bender

International Journal of Aviation, Aeronautics, and Aerospace

Not applicable.


Mitigating Interference With Knowledge-Aided Subarray Pattern Synthesis And Space Time Adaptive Processing, Yongjun Yoon 2018 Air Force Institute of Technology

Mitigating Interference With Knowledge-Aided Subarray Pattern Synthesis And Space Time Adaptive Processing, Yongjun Yoon

Theses and Dissertations

Phased arrays are essential to airborne ground moving target indication (GMTI), as they measure the spatial angle-of-arrival of the target, clutter, and interference signals. The spatial and Doppler (temporal) frequency is utilized by space-time adaptive processing (STAP) to separate and filter out the interference from the moving target returns. Achieving acceptable airborne GMTI performance often requires fairly large arrays, but the size, weight and power (SWAP) requirements, cost and complexity considerations often result in the use of subarrays. This yields an acceptable balance between cost and performance while lowering the system’s robustness to interference. This thesis proposes the use ...


Control Of Multi-Agent Collaborative Fixed-Wing Uass In Unstructured Environment, A Ram (Bella) Kim 2018 Iowa State University

Control Of Multi-Agent Collaborative Fixed-Wing Uass In Unstructured Environment, A Ram (Bella) Kim

A Ram (Bella) Kim

Swarms of unmanned aircraft are the inevitable future of the aerospace industry. In recent years, swarming robots and aircraft have been a subject of much interest; however, many research projects make impractical assumptions such as point mass dynamics with no aerodynamic effects for aircraft models, and most works stop short of fully validating their methods via flight testing. This work presents a proximity based guidance, navigation, and control of multi-agent fixed-wing unmanned aerial systems in an unstructured environment. A scalable swarm navigation method is developed using adaptive moving mesh partial differential equations controlled by the free energy heat flow equation ...


Validation And Verification Of Gnc For Large Fixed-Wing Unmanned Aerial System In Unstructured And Noisy Environment, A Ram (Bella) Kim 2018 Iowa State University

Validation And Verification Of Gnc For Large Fixed-Wing Unmanned Aerial System In Unstructured And Noisy Environment, A Ram (Bella) Kim

A Ram (Bella) Kim

The impact of high update rate on the disparity in eigenvalues of the auto-correlation matrix, along with slow convergence and reduced stability of numerical analysis are well studied. However, the impact of high update rates of autopilots on the performance of unmanned aircraft has been ignored due to the intrinsic limitations of COTS autopilots
computation power. Although MEMS based IMUs have very high update rates, the majority of existing UAS autopilot system processing power is limited to 20 Hz. In this work, the challenges and processes for developing and flight test validating an autonomous flight controller for a large 30-kg ...


Role Of Diagnostic Monitoring Software Versus Fault-Tolerant Components In The Development Of Spacecraft Avionics Systems, Andrew Attorri 2018 Union College

Role Of Diagnostic Monitoring Software Versus Fault-Tolerant Components In The Development Of Spacecraft Avionics Systems, Andrew Attorri

Honors Theses

In any spacecraft, there are several systems that must work simultaneously to ensure a safe mission. One critical system is the ‘avionics’ system, which is comprised of all of the electronic controls on-board the spacecraft, as well as radio links to other craft and ground stations. These systems are present for both manned or unmanned spacecraft.

Throughout the history of spaceflight, there have been several disasters related to avionics failures. To make these systems safer and more reliable, two main strategies have been adopted. The first, more established approach is through use of fault-tolerant components, which can operate under a ...


Orbital Constellation Design And Analysis Using Spherical Trigonometry And Genetic Algorithms: A Mission Level Design Tool For Single Point Coverage On Any Planet, Joseph R. Gagliano 2018 Cal Poly, SLO

Orbital Constellation Design And Analysis Using Spherical Trigonometry And Genetic Algorithms: A Mission Level Design Tool For Single Point Coverage On Any Planet, Joseph R. Gagliano

Master's Theses and Project Reports

Recent interest surrounding large scale satellite constellations has increased analysis efforts to create the most efficient designs. Multiple studies have successfully optimized constellation patterns using equations of motion propagation methods and genetic algorithms to arrive at optimal solutions. However, these approaches are computationally expensive for large scale constellations, making them impractical for quick iterative design analysis. Therefore, a minimalist algorithm and efficient computational method could be used to improve solution times. This thesis will provide a tool for single target constellation optimization using spherical trigonometry propagation, and an evolutionary genetic algorithm based on a multi-objective optimization function. Each constellation will ...


Determining Feasibility Of A Propulsionless Microsatellite Formation Flight Mission, Aaron Levis 2018 California Polytechnic State University, San Luis Obispo

Determining Feasibility Of A Propulsionless Microsatellite Formation Flight Mission, Aaron Levis

Master's Theses and Project Reports

Benefits of developing missions with multiple formation flying spacecraft as an alternative to a traditional monolithic vehicle are becoming apparent. In some cases, these missions can lower cost and increase flexibility among other situational advantages. However, there are various limitations that are imposed by these missions that are centered on the concept of maintaining the necessary formation. One such limitation is that of the propulsion system required for each spacecraft. To mitigate the complexity and mass of the onboard propulsion, the pairing of electromagnetic actuators and differential drag to replace the functionality of a propulsive system is investigated. By using ...


Depot For Martian And Extraterrestrial Transport Resupply (Demetr), Emily Beckman, Ethan Vogel, Caleb Peck, Nicholas Patterson 2018 University of Tennessee-Knoxville

Depot For Martian And Extraterrestrial Transport Resupply (Demetr), Emily Beckman, Ethan Vogel, Caleb Peck, Nicholas Patterson

University of Tennessee Honors Thesis Projects

No abstract provided.


Active Permanent Magnet Attitude Control For Cubesats Using Mu-Metal Shielding, Maxwell Martin 2018 University of Arkansas, Fayetteville

Active Permanent Magnet Attitude Control For Cubesats Using Mu-Metal Shielding, Maxwell Martin

Mechanical Engineering Undergraduate Honors Theses

Cube-Satellites (CubeSats) are nanosatellites composed of cube shaped units, each nominally 10cm to a side and around 1kg in mass. Due to their inherent size and weight limitations, it is often impractical to use conventional attitude, or rotational, control methods such as thrusters on these small satellites. Several methods, including magnetorquer rods and small reaction wheels, are often used instead of traditional methods to work around the size and weight limitations. As a new alternative to these methods, a permanent magnet mounted on a rotatable shaft could be used to achieve attitude control. In much the same way that a ...


Single Axis Stability Autonomous Glider Control, Brian Study 2018 Embry-Riddle Aeronautical University

Single Axis Stability Autonomous Glider Control, Brian Study

Student Works

To investigate and increase knowledge on autonomous control systems, an autonomous glider was fitted with a control system with the purpose of creating a craft that would be capable of maintaining a wings level condition despite perturbations to the trim condition. The glider measures bank angle and roll rate information from an accelerometer and gyro, before it relays the data to an equipped microcontroller. Programmed on the microcontroller is a control law to take the input from the sensors and issue a command to a single servo that controls both ailerons, allowing for the vehicle to autonomously correct its bank ...


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