Stability Analysis Of A More General Class Of Systems With Delay-Dependent Coefficients, 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 ...
Optimal Attitude Control Of A Two-Cubesat Virtual Telescope In A Highly Elliptical Orbit, 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, 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, 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, 2018 Louisiana State University
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, 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
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 ...
Book Review: Fundamentals Of International Aviation, 2018 Embry-Riddle Aeronautical University - Worldwide
Book Review: Fundamentals Of International Aviation, Alan Bender
International Journal of Aviation, Aeronautics, and Aerospace
Mitigating Interference With Knowledge-Aided Subarray Pattern Synthesis And Space Time Adaptive Processing, 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 ...
Determining Feasibility Of A Propulsionless Microsatellite Formation Flight Mission, 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 ...
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 ...
Role Of Diagnostic Monitoring Software Versus Fault-Tolerant Components In The Development Of Spacecraft Avionics Systems, Andrew Attorri
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 ...
Non-Linear Controls Project Report, 2018 Utah State University
Non-Linear Controls Project Report, Rachit Bhatia
Depot For Martian And Extraterrestrial Transport Resupply (Demetr), 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, 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, 2018 Embry-Riddle Aeronautical University
Single Axis Stability Autonomous Glider Control, Brian Study
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 ...
Safety Analysis Of Automatic Dependent Surveillance – Broadcast (Ads-B) System, 2018 Embry-Riddle Aeronautical University
Safety Analysis Of Automatic Dependent Surveillance – Broadcast (Ads-B) System, Rajee Olaganathan
ADS-B is one of the significant implementation systems of NextGen, to help pilots and air traffic controllers to create a safer, and more efficient National Airspace System (NAS). First, this research paper will briefly describe the ADS-B system, its design structure, ADS-B In and ADS-B Out systems, its efficiency both in pilot applications and in air traffic control applications, and then discuss about the system safety analysis. The preliminary hazard analysis and fault tree analysis will be done for the identified and selected hazards, and will be briefly discussed. The paper will conclude by providing recommendations to prevent/mitigate the ...
Integrity Monitoring For Automated Aerial Refueling: A Stereo Vision Approach, 2018 Air Force Institute of Technology
Integrity Monitoring For Automated Aerial Refueling: A Stereo Vision Approach, Thomas R. Stuart
Theses and Dissertations
Unmanned aerial vehicles (UAVs) increasingly require the capability to y autonomously in close formation including to facilitate automated aerial refueling (AAR). The availability of relative navigation measurements and navigation integrity are essential to autonomous relative navigation. Due to the potential non-availability of the global positioning system (GPS) during military operations, it is highly desirable that relative navigation can be accomplished without the use of GPS. This paper develops two algorithms designed to provide relative navigation measurements solely from a stereo image pair. These algorithms were developed and analyzed in the context of AAR using a stereo camera system modeling that ...
An Exploration Of Error-Correcting Codes For Use In Noise-Prone Satellite Environments, 2018 Air Force Institute of Technology
An Exploration Of Error-Correcting Codes For Use In Noise-Prone Satellite Environments, Min W. Kang
Theses and Dissertations
Satellites are crucial for the modern world to function properly as they provide Global Navigation Satellite System (GNSS) and global communication. However, the data that is stored on these satellites can be corrupted by the radiation found in space, and its bits can be improperly flipped. In the past, Forward Error Correction (FEC) algorithms were selected based on their strength and implemented to correct these bit flips back to their original values. This thesis seeks to determine if the strength of the FEC algorithms Reed Solomon (RS) code and Reed Solomon Product Code (RSPC) directly translates to their effectiveness. These ...
Modeling A Space-Based Quantum Link, 2018 Air Force Institute of Technology
Modeling A Space-Based Quantum Link, Alexander W. Duchane
Theses and Dissertations
Quantum sources and single photon detectors have improved, allowing quantum algorithms for communication, encryption, computing, and sensing to transition from theory and small-scale laboratory experiments to field experiments. One such quantum algorithm, Quantum Key Distribution, uses optical pulses to generate shared random bit strings between two locations. These shared bit strings can be turned into encryption keys to be used as a one-time-pad or integrated with symmetric encryption techniques such as the Advanced Encryption Standard. This method of key generation and encryption is resistant to future advances in quantum computing which significantly degrade the effectiveness of current asymmetric key sharing ...
Design And Test Of A Uav Swarm Architecture Over A Mesh Ad-Hoc Network, 2018 Air Force Institute of Technology
Design And Test Of A Uav Swarm Architecture Over A Mesh Ad-Hoc Network, Timothy J. Allen
Theses and Dissertations
The purpose of this research was to develop a testable swarm architecture such that the swarm of UAVs collaborate as a team rather than acting as several independent vehicles. Commercial-off-the-shelf (COTS) components were used as they were low-cost, readily available, and previously proven to work with at least two networked UAVs. Initial testing was performed via software-in-the-loop (SITL) demonstrating swarming of three simulated multirotor aircraft, then transitioned to real hardware. The architecture was then tested in an outdoor nylon netting enclosure. Command and control (C2) was provided by software implementing an enhanced version of Reynolds’ flocking rules via an onboard ...