Navigation, Guidance, Control and Dynamics Commons^™

Improving Airplane Touchdown Control By Utilizing The Adverse Elevator Effect, Nihad E. Daidzic Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

The main objective of this original research article is to understand the short-term dynamic behavior of the transport-category airplane during landing flare elevator control application. Increasing the pitch angle to arrest the sink rate, the elevator will have to produce negative lift to rotate the airplane’s nose upward. This has an immediate adverse effect of initially accelerating airplane downward. A mathematical model of landing flare based on the flat-Earth longitudinal dynamics of rigid airplane was developed which is realistic only on very short time-scales as pitch stiffness and damping were neglected. Pilot control scenarios using impulse and step elevator pull-up …

Localization And System Identification Of A Quadcopter Uav, Kenneth Befus

Masters Theses

The research conducted explores the comparison of several trilateration algorithms as they apply to the localization of a quadcopter micro air vehicle (MAV). A localization system is developed employing a network of combined ultrasonic/radio frequency sensors used to wirelessly provide range (distance) measurements defining the location of the quadcopter in 3-dimensional space. A Monte Carlo simulation is conducted using the extrinsic parameters of the localization system to evaluate the adequacy of each trilateration method as it applies to this specific quadcopter application. The optimal position calculation method is determined.

Furthermore, flight testing is performed in which real range measurement data …

Filtered-Dynamic-Inversion Control For Fixed-Wing Unmanned Aerial Systems, Jon Mullen

Theses and Dissertations--Mechanical and Aerospace Engineering

Instrumented umanned aerial vehicles represent a new way of measuring turbulence in the atmospheric boundary layer. However, autonomous measurements require control methods with disturbance-rejection and altitude command-following capabilities. Filtered dynamic inversion is a control method with desirable disturbance-rejection and command-following properties, and this controller requires limited model information. We implement filtered dynamic inversion as the pitch controller in an altitude-hold autopilot. We design and numerically simulate the continuous-time and discrete-time filtered-dynamic-inversion controllers with anti-windup on a nonlinear aircraft model. Finally, we present results from a flight experiment comparing the filtered-dynamic-inversion controller to a classical proportional-integral controller. The experimental results show …

Robust And Adaptive Nonlinear Control Of Limit Cycle Oscillations In Uavs Using Synthetic Jet Actuators, Natalie Ramos Pedroza

Doctoral Dissertations and Master's Theses

Limit cycle oscillations (LCO), also known as utter, cause significant challenges in fight control of unmanned aerial vehicles (UAVs), and could potentially lead to structural damage and catastrophic failures. LCO can be described as vibrational motions in the pitching and plunging displacements of an aircraft wing. Even in low Reynolds number (low-Re) fight regimes, LCO can exceed the limiting boundary for safe UAV fight. Further, as practical considerations motivate the design of smaller, lighter weight UAVs, there is a growing need for UAV systems that do not require heavy mechanical actuators (e.g., ailerons). To address this, the use of synthetic …

Autonomous Capabilities For Small Unmanned Aerial Systems Conducting Radiological Response: Findings From A High-Fidelity Discovery Experiment, Brittany Duncan, Robin Murphy

School of Computing: Faculty Publications

This article presents a preliminary work domain theory and identifies autonomous vehicle, navigational, and mission capabilities and challenges for small unmanned aerial systems (SUASs) responding to a radiological disaster. Radiological events are representative of applications that involve flying at low altitudes and close proximities to structures. To more formally understand the guidance and control demands, the environment in which the SUAS has to function, and the expected missions, tasks, and strategies to respond to an incident, a discovery experiment was performed in 2013. The experiment placed a radiological source emitting at 10 times background radiation in the simulated collapse of …

Adaptive Control Techniques For Transition-To-Hover Flight Of Fixed-Wing Uavs, Brian Decimo Marchini

Master's Theses

Fixed-wing unmanned aerial vehicles (UAVs) with the ability to hover combine the speed and endurance of traditional fixed-wing fight with the stable hovering and vertical takeoff and landing (VTOL) capabilities of helicopters and quadrotors. This combination of abilities can provide strategic advantages for UAV operators, especially when operating in urban environments where the airspace may be crowded with obstacles. Traditionally, fixed-wing UAVs with hovering capabilities had to be custom designed for specific payloads and missions, often requiring custom autopilots and unconventional airframe configurations. With recent government spending cuts, UAV operators like the military and law enforcement agencies have been urging …

Aircraft Tests Arrive At Numbers Pilots Need For Safe Operations, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Integrated Collision Avoidance System Sensor Evaluation Final Design Project, Alex F. Graebe, Bridgette S. Kimball, Drew T. Lavoise

Mechanical Engineering

Following the development of Aircraft Collision Avoidance Technology (ACAT) by the National Aeronautics and Space Administration (NASA), a need arose to transition the life-saving technology to aid the general aviation community. Considering the realistic cost of implementation, it was decided that the technology should be adapted to function on any smartphone, using that device as an end-to-end solution to sense, process, and alert the pilot to imminent threats. In September of 2012, the SAS (Sense and Survive) Senior Project Team at California Polytechnic University (Cal Poly), San Luis Obispo was assigned the task of using smartphone technology to accurately sense …

Robust Parafoil Terminal Guidance Using Massively Parallel Processing, Jonathan Rogers, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Terminal guidance of autonomous parafoils is a difficult problem in which wind uncertainty and system underactuation are major challenges. Existing strategies almost exclusively use impact error as the criterion for optimality. Practical airdrop systems, however, must also include other criteria that maybe even more important than impact error for some missions, such as ground speed at impact or constraints imposed by drop zones with restrictions on flight patterns. Furthermore, existing guidance schemes determine terminal trajectories using deterministic wind information and may result in a solution that works in ideal wind but may be sensitive to variations. The work described here …

Determination Of Human Powered Helicopter Stability Characteristics Using Multi-Body System Simulation Techniques, Sean M. Brown

Master's Theses

Multi-Body System Simulation combined with System Identification was developed as a method for determining the stability characteristics of a human powered helicopter(HPH) configurations. HPH stability remains a key component for meeting competition requirements, but has not been properly treated. Traditional helicopter dynamic analysis is not suited to the HPH due to its low rotation speeds and light weight. Multi-Body System Simulation is able to generate dynamic response data for any HPH configuration. System identification and linear stability theory are used to determine the stability characteristics from the dynamic response. This thesis focuses on the method development and doesn't present any …

Development Of A Pyrotechnic Shock Simulation Apparatus For Spacecraft Applications, Joseph Binder, Matthew Mccarty, Chris Rasmussen

Aerospace Engineering

This report details the research, design, construction, and testing of a pyrotechnic shock simulation apparatus for spacecraft applications. The apparatus was developed to be used in the Space Environments Lab at California Polytechnic State University. It will be used for testing spacecraft components with dimensions up to 24”x12”x12” as well as CubeSats. Additionally, it may be used as an instructional or demonstrational tool in the Aerospace Department’s space environments course. The apparatus functions by way of mechanical impact of an approximately 20 lb stainless steel swinging hammer. Tests were performed to verify the simulator’s functionality. Suggestions for improvement and further …

Nonlinear Uav Flight Control Using Command Filtered Backstepping, Brian M. Borra

Master's Theses

The aim of this effort is to implement a nonlinear flight control architecture, specifically flight path control via command filtered backstepping, for use in AME UAS's Fury® 1500 unmanned flying wing aircraft. Backstepping is a recursive, control-effort minimizing, constructive design procedure that interlaces the choice of a Lyapunov function with the design of feedback control. It allows the use of certain plant states to act as intermediate, virtual controls, for others breaking complex high order systems into a sequence of simpler lower-order design tasks.

Work herein is a simplified implementation based on publications by Farrell, Sharma, and Polycarpou. Online approximation …

Specialized System Identification For Parafoil And Payload Systems, Michael Ward, Mark Costello, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

There are a number of peculiar aspects to parafoil and payload systems that make it difficult to apply conventional system identification procedures used for aerospace systems. Parafoil and payload systems are unique because typically there is very little sensor information available, the sensors that are available are separated from the canopy by a complex network of flexible rigging, the systems are very sensitive to wind and turbulence, the systems exhibit a number of nonlinear behaviors, and the systems exhibit a high degree of variability from flight to flight. The current work describes a robust system identification procedure developed to address …

Evaluation Of Multibody Parafoil Dynamics Using Distributed Miniature Wireless Sensors, Chrystine M. Gorman, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Guided parafoils arc composed of two primary bodies, a payload and parafoil. The payload encompasses the majority ofthe ovcrdll system mass; however, the parafoil generates the majority of aerodynamic loads and is the sole source of control. Despite the canopy being the source of control, the sensor systems used for guidance are located away from the parafoil. Many multi body models exist in literature and use different degrees of freedom to represent parafoil-payload relative motion. However, in many cases, simulations are used to investigate how the relative motion between bodies affects the overall dynamics without experimental validation determining the accuracy …

Imu Integration To The Cal Poly Spacecraft Attitude Dynamics Simulator Power System, Wayland Chan

Electrical Engineering

The Cal Poly Spacecraft Attitude Dynamics Simulator mimics the rotation dynamics of a spacecraft in orbit and acts as a test bed for spacecraft attitude control system development and demonstration. Prior to this project, the simulator measured its attitude dynamics from a total of seven sensors mounted on to the platform, including three micro-electromechanical system (MEMs) gyroscopes, and four motor encoders. This project entails the installation of an LN-200 high performance gyroscope, which will provide a greater measure of accuracy. The goal of this project is to design a power circuit that will integrate the LN-200 inertial measurement unit onto …

Airplane Landing Flare-The Last 5 Seconds, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Some Considerations For Regional Airline Operations On Contaminated Runways., Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Guidance, Navigation And Control Of A Fly-By-Wire Transport Category Airship Designed For Hover Cargo Delivery, Harshad H. Lalan

Master's Theses - Daytona Beach

The purpose of this thesis is to develop fly-by-wire pilot controls for a transport category airship propelled with six thrust vectoring engines, and to develop control laws to maintain position, heading, and attitude during hover and cargo operations. Owing to the large body area, most airships require that they be pointed into the wind to maintain their position. This research aims at controlling an airship attitude and position during hover cargo delivery, irrespective of the wind direction.

Control laws were developed for two primary modes of the airship: Flight (High Speed Mode) and Hover (Cargo Delivery Mode). Different sets of …

Unmanned Aerial Vehicles Collision Avoidance From Moving Obstacles, Atila Ozdemir

Electrical & Computer Engineering Theses & Dissertations

The usage of the unmanned aerial vehicles (UAV) is becoming more diverse day by day in both military and civil applications. Specifically in military applications, they are becoming a "must-have" component in every arsenal. Low cost, and especially the importance of human life, makes these vehicles desired in any military situation. But in order to take advantage of the UAVs, these vehicles should be able to navigate safely and not collide with other air vehicles, especially ones that are manned and carry personnel. As a result, the importance of a collision avoidance system of the UA V arises and begins …

Terminal Guidance Of Autonomous Parafoils In High Wind-To-Airspeed Ratios, Nathan Slegers, O A. Yakimenko

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Autonomous precision placement of parafoils is challenging because of their limited control authority and sensitivity to winds. In particular, when wind speed is near the airspeed, guidance is further complicated by the parafoils inability to penetrate the wind. This article specifically addresses the terminal phase and develops an approach for generating optimal trajectories in real-time based on the inverse dynamics in the virtual domain. The method results in efficient solution of a two-point boundary-value problem using only a single optimization parameter allowing the trajectory to be generated at a high rate, mitigating effects of the unknown winds. It is shown …

Tethered Aerostat Modeling Using An Efficient Recursive Rigid-Body Dynamics Approach, Brad Hembree, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

A tethered aerostat model is developed using a computationally efficient recursive tether model. The recursive rigid-body tether model results in unconstrained ordinary differential equations and maintains much of the simplicity of simple lumped-mass tether models, while avoiding numerical difficulties associated with using many stiff elastic elements with low mass. Further efficiency is achieved by treating each tether link as a body of revolution and assuming that tether spin is negligible to the dynamics. The tether is attached to a six-degree-of-freedom aerostat model using a single viscoelastic element. The final recursive tethered aerostat model is well suited for a variety of …

Adverse Elevator Effect In Landing Flare, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Monocular Vision Localization Using A Gimbaled Laser Range Sensor, Don J. Yates

Theses and Dissertations

There have been great advances in recent years in the area of indoor navigation. Many of these new navigation systems rely on digital images to aid an inertial navigation estimates. The Air Force Institute of Technology (AFIT) has been conducting research in this area for a number of years. The image-aiding techniques are centered around tracking stationary features in order to improve inertial navigation estimates. Previous research has used stereo vision systems or terrain constraints with monocular systems to estimate feature locations. While these methods have shown good results, they do have drawbacks. First, as unmanned exploration vehicles become smaller …

Efficient Tether Dynamic Model Formulation Using Recursive Rigid-Body Dynamics, Brad Hembree, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

A computationally efficient discrete model for low-strain tethers used in many engineering applications is developed without the use of elastic elements. The tether is modelled using N links, with each link treated as a body of revolution where it is assumed the tether spin is negligible to the dynamics, resulting in each link having only two degrees of freedom. A recursive algorithm is developed for the dynamic equations, with the solution procedure being an order N method requiring only a 2 x 2 matrix inversion, resulting in approximately half the computations of the general recursive algorithm. A comparison between the …

Effects Of Canopy-Payload Relative Motion On Control Of Autonomous Parafoils, Nathan Slegers

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

An 8 degree-of-freedom model is developed that accurately models relative pitching and yawing motion of a payload with respect to a parafoil. Constraint forces and moments are found analytically rather than using artificial constraint stabilization. A turn rate controller common in precision placement algorithms is used to demonstrate that relative yawing motion of the payload can result in persistent oscillations of the system. A model neglecting relative payload yawing failed to predict the same oscillations. It is shown that persistent oscillations can be eliminated by reduction of feedback gains; however, resulting tracking performance is poor. A reduced order linear model …

Avoiding Overrun Accidents On Contaminated Runways, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Avoiding Aircraft Icing Accidents, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Avoiding Veer-Off Accidents On Contaminated Runways, Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

Design Of A "Figure-8" Spherical Motion Flapping Wing For Miniature Uav's, Zohaib Parvaiz Rehmat

UNLV Theses, Dissertations, Professional Papers, and Capstones

Hummingbirds and some insects exhibit a Figure-8 motion, which allows them to undergo variety of maneuvers including hovering. It is therefore desirable to have flapping wing miniature air vehicles (FWMAV) that can replicate this unique wing motion. In this research, a design of a flapping wing for FWMAV that can mimic Figure-8 motion using a spherical four bar mechanism is presented. To produce Figure-8 motion, the wing is attached to the coupler point of the spherical four bar mechanism and driven by a DC servo motor. For verification of the design, a prototype of the wing and mechanism is fabricated …

A Flight Simulation Study Of The Simultaneous Non-Interfering Aircraft Approach, Brian H. Reel

Master's Theses

Using a new implementation of a NASA flight simulation of the Quiet Short-Haul Research Aircraft, autopilots were designed to be capable of flying both straight in (ILS) approaches, and circling (SNI) approaches. A standard glideslope coupler was sufficient for most conditions, but a standard Proportional-Integral-Derivative (PID) based localizer tracker was not sufficient for maintaining a lateral track on the SNI course. To track the SNI course, a feed-forward system, using GPS steering provided much better results.

NASA and the FAA embrace the concept of a Simultaneous, Non-Interfering (SNI) approach as a way to increase airport throughput while reducing the noise …