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Synthetic Jet Actuator-Based Aircraft Tracking Using A Continuous Robust Nonlinear Control Strategy, N. Ramos-Pedroza, W. Mackunis, M. Reyhanoglu

Publications

A robust nonlinear control law that achieves trajectory tracking control for unmanned aerial vehicles (UAVs) equipped with synthetic jet actuators (SJAs) is presented in this paper. A key challenge in the control design is that the dynamic characteristics of SJAs are nonlinear and contain parametric uncertainty. The challenge resulting from the uncertain SJA actuator parameters is mitigated via innovative algebraic manipulation in the tracking error system derivation along with a robust nonlinear control law employing constant SJA parameter estimates. A key contribution of the paper is a rigorous analysis of the range of SJA actuator parameter uncertainty within which asymptotic …

Highly Vented Truss Wall Honeycomb Structures, David J. Sypeck

Publications

A vented honeycomb structure with a plurality of honey­comb cells arranged in a hierarchical order and having a plurality of truss walls, each truss wall including a plurality of members. The vented honeycomb structure is fabricated by joining a plurality of sheets of trusses using any one of an expansion, a corrugation, and a slotting process. Fabri­cation can also occur by deposition, casting, additive, extru­sion, or aligning and joining methods. The honeycomb cells, truss walls, truss wall openings, and truss wall members can be functionally graded.

Highly Vented Truss Wall Honeycomb Structures, David J. Sypeck

Publications

A vented honeycomb structure with a plurality of honey­comb cells arranged in a hierarchical order and having a plurality of truss walls, each truss wall including a plurality of members. The vented honeycomb structure is fabricated by joining a plurality of sheets of trusses using any one of an expansion, a corrugation, and a slotting process. Fabri­cation can also occur by deposition, casting, additive, extru­sion, or aligning and joining methods. The honeycomb cells, truss walls, truss wall openings, and truss wall members can be functionally graded.

Flight Dynamics: Flying Qualities Of Handling Factors Are Engineered Into The Aircraft Design, Nihad E. Daidzic

Aviation Department Publications

Flight dynamics is an aerospace engineering discupline that addresses aircraft stability and controllability. It is also mathematically very intensive and is traditionally the most difficult in the pilot training curriculum. Ultimately, it does not matter how good steady-state performance of an aircraft design is if its flying (handling) qualities are deficient. Paradoxically, the first airplane Wright Flyer, was statically and dynamically unstable, had large control authority, and was difficult to fly. We've come a long way since those early days, but stability is still vitally important in aircraft design and flight ops. The focus of this article will be airplane …

Aerodynamic Analysis Of Low Speed Wing Design Using Taguchi L9 Orthogonal Array, Kenneth Witcher, Ian Mcandrew, Elena Vishnevskaya

Publications

The study of aerodynamics has been preoccupied with understanding flight at increasing speeds and ultimately supersonic. Today, this pursuit has advanced the science for both Hypersonic and Transonic flight to near Mach 1 supporting economical commercial flight operations. This research presents the data from a Taguchi array on low speed with twin wing designs to establish the design parameters for their use in low speed and high altitude. Also presented is how aerodynamic advantages can be achieved through understanding the interactions of parameters and their use. This is compared to operational effectiveness when applied to remotely piloted aircraft that are …

Transient Analysis Of Fracture Initiation In A Coupled Thermoelastic Solid, Louis Milton Brock

Mechanical Engineering Faculty Publications

An isotropic, thermoelastic solid is initially at rest at uniform (absolute) temperature, and contains a semi-infinite, plane crack. Application of in-plane and normal point forces to each face of the crack causes transient 3D growth. The related problem of discontinuities in temperature and displacement that exist on regions that exhibit dynamic similarity is first considered. Asymptotic expressions, whose inverses are valid near the crack edges for short times, are obtained in integral transform space. These lead to equations of the Wiener–Hopf type for the fracture problem. Analytical solutions are obtained and, upon inversion, subjected to a dynamic energy release rate …

Experimental Measurement Of Residual Stress And Distortion In Additively Manufactured Stainless Steel Components With Various Dimensions, M. Ghasri-Khouzani, H. Peng, R. Rogge, R. Attardo, P. Ostiguy, J. Neidig, R. Billo, D. Hoelzle, M. R. Shankar

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Disk-shaped 316L stainless steel parts with various diameters and heights were additively manufactured using a direct metal laser sintering (DMLS) technique. Neutron diffraction was used to profile the residual stresses in the samples before and after removal of the build plate and support structures. Moreover, distortion level of the parts before and after the removal was quantified using a coordinate measuring machine (CMM). Large tensile in-plane stresses (up to ≈ 400 MPa) were measured near the as-built disk top surfaces, where the stress magnitude decreased from the disk center to the edges. The stress gradient was steeper for the disks …

Prediction-Based Adaptive Robust Control For A Class Of Uncertain Time-Delay Systems, Jayaprakash Suraj Nandiganahalli, Cheolhyeon Kwon, Inseok Hwang

School of Aeronautics and Astronautics Faculty Publications

This paper presents an integrated control design approach for a class of dynamical systems that satisfy a certain matching condition subject to known input time-delay, unknown parameters, and time-varying disturbances, simultaneously. A novel nonlinear predictor adaptive robust control (PARC) is proposed to track a desired state trajectory. The controller uses predictor-based model compensation to attenuate the effect of input time-delay, gradient type projection with prediction-based learning mechanisms to reduce the parameter uncertainties, and prediction-based nonlinear robust feedback to attenuate the effect of model approximation errors and disturbances, simultaneously. The controller guarantees a prescribed transient performance (with global exponential convergence) and …

An Enhanced Operational Definition Of Dielectric Breakdown For Dc Voltage Step-Up Tests, Allen Andersen, Jr Dennison

Journal Articles

The imprecise definition of breakdown in the ASTM D3755-14 standard can misidentify breakdown. If the recommended test circuit current sensing element threshold is set too high, breakdown may occur undetected. Conversely, false positives may result from designating a low current threshold. An operational definition of breakdown much less sensitive to these pitfalls is outlined herein. This enhanced definition of breakdown is based on the average rate of change of the leakage current with increasing voltage, rather than a simple current threshold, avoiding ambiguous association with anomalies in current traces. For tests that continuously monitor leakage current, breakdown can be detected …

United States Drone Laws, Jacob Crittenden

Student Works

The purpose of this Directed Study was to investigate and compile the drone laws that exist within the United States, both on the federal level and for each individual state. The federal laws are directed by the Federal Aviation Administration (FAA) under laws that pertain to “Unmanned Aircraft Systems” (UAS) and are relatively new. Most states have further regulations on UAS that they have passed. Most of these laws are in place to protect public safety and privacy, but some also prohibit certain locations of flight and certain modifications that might be made to the platform. State laws that limit …

The Shaping Of Things That Are: How Airplane Windows Took Their Shape, Morgan Lopez

Student Works

Have you ever wondered why your airplane's windows are rounded? It is not for aesthetic appeal.

The first commercial jetliner windows' sole purpose was appearance; a squared window afforded an impressive view of the earth, but the view was not without consequence.

The Capabilities Of The Geostationary Operational Environmental Satellite-16 (Goes-16), Brandon M. Kane

Student Works

This report investigates the capability of the new Geostationary Operational Environmental Satellite-16 (GOES-16) satellite to display 16 channels of the electromagnetic spectrum, to produce images at a higher resolution at increased intervals, and to detect and display lightning. This report also discusses the main instrumentation aboard the new geostationary satellite and how it aids in creating accurate data collection, which in turn, produces quicker weather forecasts and warnings. The 16 different channels produced by the Advanced Baseline Imager aboard the new satellite are analyzed in detail as to the functions and wavelengths on which the channels operate. The image resolution …

Shear Joy Of Watching Paint Dry, Randy Craig Hurd, Nathan B. Spiers, J. Belden, Zhao Pan, B. Lovett, W. G. Robinson, M. A. Zamora, Saberul I. Sharker, Mohammad M. Mansoor, A. Merritt, Tadd T. Truscott

Mechanical and Aerospace Engineering Faculty Publications

This paper is associated with a video winner of a 2016 APS/DFD Milton van Dyke Award for work presented at the DFD Gallery of Fluid Motion.

Unmanned Aerial Vehicle (Uav): Flight Performance, Fevens Louis Jean

Student Works

It is important that when measuring the sideslip angle and angles of attack during flight test performance of a UAV (Unmanned Aerial Vehicle), to fully understand that the Angles of attack and sideslip are parameters that aid in determining the safety of the flight as they improve stability and control of the aircraft. The disadvantage of the measurement of these angles using this method is low accuracy of measurement due to friction to the potentiometers in connection with the vanes. To counter this, a new sensing method was developed to minimize friction and collect more accurate data. The method is …

Compensating For Cryogenic Propellant Boiloff For A Cargo Mission To Mars, Thomas M. Perrin, James Casler

Space Studies Faculty Publications

A previous work by the authors (Architecture Study for a Fuel Depot Supplied from Lunar Resources – AIAA 2016-5306) examined architectures for a fuel depot supplied from lunar ice deposits. The study recommended a fuel depot be located at Earth-Moon L1. The study used three design reference missions in the formulation of candidate architectures – among them a Mars Cargo Vehicle (MCV). Each vehicle used 60 layers of multi-layer insulation (MLI) to minimize the boiloff of cryogenic propellants. Boiloff was shown to not be a driver in architecture selection, but it was noted that reducing the number of layers of …

Simplex Solutions For Optimal Control Flight Paths In Urban Environments, Michael D. Zollars, Richard G. Cobb, David J. Grymin

Faculty Publications

This paper identifies feasible fight paths for Small Unmanned Aircraft Systems in a highly constrained environment. Optimal control software has long been used for vehicle path planning and has proven most successful when an adequate initial guess is presented flight to an optimal control solver. Leveraging fast geometric planning techniques, a large search space is discretized into a set of simplexes where a Dubins path solution is generated and contained in a polygonal search corridor free of path constraints. Direct optimal control methods are then used to determine the optimal flight path through the newly defined search corridor. Two scenarios …

Using Unmanned Aerial Vehicles (‘Drones’) To Collect Data From Tagged Fishers In The Environment, Vu A. Pham, Marc Horney, Aaron Drake

STAR Program Research Presentations

Fisher (Pekania pennant) belongs to the weasel family. In October 2014, the United States Fish and Wildlife Service proposed to list the West Coast Distinct Population Segment of fisher as threatened under the Endangered Species Act. We wish to better define where fishers live within their habitats and use that information to improve conservation efforts. Previously, to track the behavior of wild fishers, researchers put tracker collars on the animals and relied on networks of fixed antennas on the ground in the environment to collect data. We are experimenting with using unmanned aerial vehicles (‘drones’) to collect data …

A Mathematical Model And Numerical Simulations Of Redox Electrochemical Systems With Mhd And Natural Convection, Kakkattukuzhy M. Isaac, Fangping Yuan

Collaborative Research: Actively Controllable Microfluidics with Film-Confined Redox-Magnetohydrodynamics -- Video and Data

A comprehensive mathematical model for redox electrochemical systems with magnetohydrodynamics (MHD) and natural convection are presented. The model is based on density changes in isothermal systems that accompany redox reaction at the electrode due to supporting electrolyte ions migrating into and out of the diffusion layer to satisfy electroneutrality. Numerical simulations have been performed for an axisymmetric, milli-electrode electrochemical cell with gravity directed along the axis in both directions to investigate the effect of the electrode orientation with respect to gravity. Results show that natural convection is significant in both cases, with the maximum velocity being an order of magnitude …

Cyber-Physical System Characterization And Co-Regulation Of A Quadrotor Uas, Seth E. Doebbeling

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

An Unmanned Aircraft System (UAS) is a Cyber-Physical System (CPS) in which a host of real-time computational tasks contending for shared resources must be cooperatively managed to obtain mission objectives. Traditionally, control of the UAS is designed assuming a fixed, high sampling rate in order to maintain reliable performance and margins of stability. But emerging methods challenge this design by dynamically allocating resources to computational tasks, thereby affecting control and mission performance. To apply these emerging strategies, a characterization and understanding of the effects of timing on control and trajectory following performance is required. Going beyond traditional control evaluation techniques, …

Three-Dimensional Printing Of "Green" Fuels For Low-Cost Small Spacecraft Propulsion Systems, Stephen A. Whitmore

Mechanical and Aerospace Engineering Faculty Publications

This paper details the advantages of employing modern additive manufacturing methods to fabricate hybrid rocket fuels for intrinsically safe and green small spacecraft propulsion systems. Using additive manufacturing overcomes multiple issues frequently associated with hybrid propulsion, including poor volumetric efficiency, system ignitability, and low fuel regression rates. When certain three-dimensionally printed thermoplastics are subjected to a high-voltage low-wattage charge, electrostatic arcing along the surface pyrolizes a small amount of material that, with the introduction of an oxidizer, “seeds” combustion and produces immediate and reliable ignition. Thermoplastic fuel grains can be printed with port shapes that enhance burn properties and increase …

Structural Vs.. Compositional Disorder In Thermal Conductivity Reduction Of Sige Alloys, Jihui Nie, Raghavan Ranganathan, Zhi Liang, Pawel Keblinski

Mechanical and Aerospace Engineering Faculty Research & Creative Works

We Use Equilibrium Molecular Dynamics Simulations to Determine the Relative Role of Compositional and Structural Disorder in a Phononic Thermal Conductivity Reduction by Studying Three 50-50 SiGe Alloy Structures: Ordered Alloys, Disordered Alloys, and Amorphous Alloys, as Well as Pure Amorphous Si and Ge Structures for Reference. While Both Types of Disorders Significantly Reduce Thermal Conductivity, Structural Disorder is Much More Effective to This Aim. the Examination of Phonon Lifetimes in Disordered Alloys Shows High Values in a Low Frequency Regime Governed by Umklapp Scattering that Are Reduced Rapidly with Increasing Frequency Following Rayleigh Scattering Behavior. the Local Properties Analysis …

Singularity Formation In The Geometry Of Perturbed Shocks Of General Mach Number, Wouter Mostert, Dale I. Pullin, Ravi Samtaney, Vincent Wheatley

Mechanical and Aerospace Engineering Faculty Research & Creative Works

While planar shock waves are known to be stable to small perturbations in the sense that the perturbation amplitude decays over time, it has also been suggested that plane propagating shocks can develop singularities in some derivative of their geometry (Whitham (1974) Linear and nonlinear waves. Wiley, New York) in a nonlinear, wave reinforcement process. We present a spectral-based analysis of the equations of geometrical shock dynamics that predicts the time to singularity formation in the profile of an initially perturbed planar shock for general shock Mach number. We find that following an initially sinusoidal perturbation, the shock shape remains …

Implementing Conditional Inequality Constraints For Optimal Collision Avoidance, Nathan E. Smith, Christopher D. Arendt, Richard G. Cobb, Jonah A. Reeger

Faculty Publications

Current Federal Aviation Administration regulations require that passing aircraft must either meet a specified horizontal or vertical separation distance. However, solving for optimal avoidance trajectories with conditional inequality path constraints is problematic for gradient-based numerical nonlinear programming solvers since conditional constraints typically possess non-differentiable points. Further, the literature is silent on robust treatment of approximation methods to implement conditional inequality path constraints for gradient-based numerical nonlinear programming solvers. This paper proposes two efficient methods to enforce conditional inequality path constraints in the optimal control problem formulation and compares and contrasts these approaches on representative airborne avoidance scenarios. The first approach …

Suitability Testing For Possum Scientist-Astronaut Candidates Using The Suborbital Space Flight Simulator With An Iva Spacesuit, Pedro J. Llanos, Victor Kitmanyen, Erik Seedhouse, Ryan L. Kobrick

Publications

This paper evaluates key functional data parameters that must be considered for suborbital spaceflight participants wearing pressurized suits for intravehicular activity (IVA). Data parameters of an analog spacesuit worn in an analog flight environment were obtained from 40 civilian participants using the Suborbital Space Flight Simulator (SSFS) at Embry-Riddle Aeronautical University (ERAU) while donning Final Frontier Design’s (FFD) fully pressurized third-generation spacesuit as part of their training for Project PoSSUM (the Polar Suborbital Science in the Upper Mesosphere Project). The physiological data collected included: blood pressure, electrocardiograms, heart rate, grip strength, and skin temperature. These parameters were measured using a …

Mapping Of Iva Spacesuit Mobility: Design Observations And Functionality, Gavin C. James, Ryan L. Kobrick, Victor Kitmanyen

Publications

The SUIT Lab at Embry-Riddle Aeronautical University is a joint student-faculty project utilizing multiple high altitude pressure garments to investigate suited crew capabilities within a spacecraft during simulated spaceflight missions. The testing environment within the SUIT lab includes the use of suits in a lowfidelity capsule cabin mockup with a horizontally situated launch-positioned chair simulator. Standard videography and analytical video software are used to determine levels of achievement in ergonomic range of motion and comfort design across multiple spacesuits. Comparative analysis and testing provide data supporting the requirement for the use of particular spacesuits inside proposed commercial launch vehicles. Results …

Human Factors For Small Net Habitable Volume: The Case For A Close-Quarter Space Habitat Analog, Victor Kitmanyen, Timothy J. Disher, Ryan L. Kobrick, Jason P. Kring

Publications

Increasing efforts in sending humans to Mars calls for greater considerations of the ways in which vehicle and habitat design can influence crew performance and behavioral health.

Six Degrees Of Freedom From Six Degrees Of Separation: The History Of Flight Simulators, David Keck, Morgan Lopez

Publications

Some of today's advanced flight simulators have the capacity to provide pilots with experiences of six degrees of freedom: forward/backward, up/down, or left/right (or pitching, rolling, or yawing in either direction). These incredible devices are the product of over 100 years of design developments that come from a series of technological discoveries and historical events.

Time Optimal State Feedback Control With Application To A Spacecraft With Cold Gas Propulsion, Samuel J. Kitchen-Mckinley, Sergey V. Drakunov

Publications

A cold gas propulsion system is well suited to provide the required thrust for a small surveyor spacecraft operated near an asteroid or planetary surface. The cold gas propellant can obtained in-situ from local surface or atmospheric constituents. For small spacecraft, the cold gas system may be limited to only on-off control of the main tank where the generated thrust is directly dependent on the tank pressure. As such the thrust will slowly decrease as the propellant is expended. A state feedback, time optimal, control law is developed for a vehicle with propellant is expended. A state feedback, time optimal, …

Novel Layered Double Hydroxides-Hydroxyapatite/Gelatin Bone Tissue Engineering Scaffolds: Fabrication, Characterization, And In Vivo Study, Fateme Fayyazbakhsh, Mehran Solati-Hashjin, Abbas Keshtkar, Mohammad Ali Shokrgozar, Mohammad Mehdi Dehghan, Bagher Larijani

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Developing Porous Biodegradable Scaffolds through Simple Methods is One of the Main Approaches of Bone Tissue Engineering (BTE). in This Work, a Novel BTE Composite Containing Layered Double Hydroxides (LDH), Hydroxyapatite (HA) and Gelatin (GEL) Was Fabricated using Co-Precipitation and Solvent-Casting Methods. Physiochemical Characterizations Showed that the Chemical Composition and Microstructure of the Scaffolds Were Similar to the Natural Spongy Bone. Interconnected Macropores Ranging over 100 to 600 Μm Were Observed for Both Scaffolds While the Porosity of 90 ± 0.12% and 92.11 ± 0.15%, as Well As, Young's Modulus of 19.8 ± 0.41 and 12.5 ± 0.35 GPa Were …

Creating An Experimental Learning And Research Driven Spacesuit Lab For Erau, Ryan L. Kobrick, Erik Seedhouse

Publications

This paper evaluates key functional data parameters that must be considered for suborbital spaceflight participants wearing pressurized suits for intravehicular activity (IVA). Data parameters of an analog spacesuit worn in an analog flight environment were obtained from 40 civilian participants using the Suborbital Space Flight Simulator (SSFS) at Embry-Riddle Aeronautical University (ERAU) while donning Final Frontier Design’s (FFD) fully pressurized third-generation spacesuit as part of their training for Project PoSSUM (the Polar Suborbital Science in the Upper Mesosphere Project). The physiological data collected included: blood pressure, electrocardiograms, heart rate, grip strength, and skin temperature. These parameters were measured using a …