Systems Engineering and Multidisciplinary Design Optimization Commons^™

A Comparison Of Filtering Approaches For Aircraft Engine Health Estimation, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

Different approaches for the estimation of the states of linear dynamic systems are commonly used, the most common being the Kalman filter. For nonlinear systems, variants of the Kalman filter are used. Some of these variants include the LKF (linearized Kalman filter), the EKF (extended Kalman filter), and the UKF (unscented Kalman filter). With the LKF and EKF, performance varies depending on how often Jacobians (partial derivative matrices) are updated. In other words, we see a tradeoff between computational effort and filtering performance. With the unscented Kalman filter, Jacobians are not calculated but computational effort is typically high due to …

Towards A Metric For The Assessment Of Safety Critical Control Systems, Oscar R. Gonzalez, Jorge R. Chavez-Fuentes, W. Steven Gray

Electrical & Computer Engineering Faculty Publications

There is a need for better integration of the fault tolerant and the control designs for safety critical systems such as aircraft. The dependability of current designs is assessed primarily with measures of the interconnection of fault tolerant components: the reliability function and the mean time to failure. These measures do not directly take into account the interaction of the fault tolerant components with the dynamics of the aircraft. In this paper, a first step to better integrate these designs is made. It is based on the observation that unstable systems are intrinsically unreliable and that a necessary condition for …

A Design Of Experiments Approach To Deck Flow Characterization On An Aircraft Carrier, Yugapriya Sivanesan Wing

Mechanical & Aerospace Engineering Theses & Dissertations

A wind tunnel model of an aircraft carrier was used to make air wake measurements. Particle image velocimetry measurements of turbulence intensity were made on a center plane intersecting the angled deck of the aircraft carrier. The factors of interest for the study were model pitch, yaw, island location, and island type. Two island types were used, a representative shape of current designs and an ideal streamlined airfoil shape. Each factor was studied at two levels in order to provide linear models using a Design of Experiments factorial design. From the data for each experimental combination, regression models for turbulence …

Assessment Of Preliminary Design Approaches For Metallic Stiffened Cylindrical Shell Instability Problems, Vicki Owen Britt

Mechanical & Aerospace Engineering Theses & Dissertations

A preliminary design tool for metallic stiffened fuselage cylindrical panels subjected to longitudinal compression has been developed and validated by comparison to test results. Several methodologies for stiffened panel buckling and failure predictions were examined and evaluated. An appropriate level of analysis fidelity was determined for different failure modes and design details. Results from panel tests conducted to verify analytical methods used to design the Gulfstream V aircraft were presented. The panels were representative of four general skin/stringer configurations on the aircraft. Finite Element analyses and standard analytical methods were used to predict panel failure loads. The accuracy of the …

Investigation Into Nanocomposites For Applications In Lightning Strike Protection, Matthew S. Bond, James A. Rodriguez, Hieut T. Nguyen

Theses and Dissertations

The United States Air Force is continually researching ways to reduce costs associated with aircraft maintenance and improve operational safety. This study focuses on creating a systems engineering process to develop an Integrated Structural Health Monitoring System (ISHMS). The overarching process was then applied to design a conceptual ISHMS for a real-world scenario involving the F-15. Sensor selection, integration and testing were explored in detail using frequency response methods to detect structural damage. Testing was accomplished using a simplified structural specimen with Monitoring & Evaluation Technology Integration System (METIS) disk nodes attached at various locations. Two different METIS disk operation …

Determining Logistics Ground Support Manpower Requirements For A Reusable Military Launch Vehicle, Sydney C. Michalski

Theses and Dissertations

Successful space-based technologies like satellite imagery and GPS have increased military demand for a rapid-response launch capability. AF Space Command's Operationally Responsive Spacelift program was developed to ensure that the AF has the capability to launch a payload into orbit within hours of a tasking notification, and requires development of a new space launch vehicle. The Reusable Military Launch Vehicle (RMLV) is currently in the design phase. The AF Research Laboratory sponsored development of the MILEPOST simulation model in order to assess the turnaround time, and thus responsiveness, of various design alternatives. The focus of this thesis is to improve …

Prioritizing Satellite Payload Selection Via Optimization, Benjamin S. Kallemyn

Theses and Dissertations

This thesis develops optimization models for prioritizing payloads for inclusion on satellite buses with volume, power, weight and budget constraints. The first model considers a single satellite launch for which the budget is uncertain and constellation requirements are not considered. Subsequently, we include constellation requirements and provide a more enhanced model. Both single-launch models provide a prioritized list of payloads to include on the launch before the budget is realized. The single-launch models are subsequently extended to a sequence of multiple launches in two cases, both of which incorporate an explicit dependence on the constellation composition at each launch epoch. …

Innovative Schematic Concept Analysis For A Space Suit Portable Life Support Subsystem, M. Schuller, R. Kobrick, T. Lalk, L. Wiseman, F. Little, Et Al.

Publications

Conceptual designs for a space suit Personal Life Support Subsystem (PLSS) were developed and assessed to determine if upgrading the system using new, emerging, or projected technologies to fulfill basic functions would result in mass, volume, or performance improvements. Technologies were identified to satisfy each of the functions of the PLSS in three environments (zero-g, Lunar, and Martian) and in three time frames (2006, 2010, and 2020). The viability of candidate technologies was evaluated using evaluation criteria such as safety, technology readiness, and reliability. System concepts (schematics) were developed for combinations of time frame and environment by assigning specific technologies …

Most Probable Point-Based Design Optimization, Akhil R. Tipnis

Mechanical & Aerospace Engineering Theses & Dissertations

Modem products ranging from simple components to complex systems should be designed to be optimal and reliable. The challenge of modem engineering is to ensure that manufacturing costs are reduced and design cycle times are minimized while achieving requirements for performance and reliability. If the market for the product is competitive, improved quality and reliability can generate very strong competitive advantages. Reliability based design optimization plays a very important role in designing almost any kind of product. This investigation focuses on the development of the hybrid PMNRIA approach which uses the active-in-reliability concept for reliability based design optimization. The efficiency …

A Comparative Analysis Of Transmission Control Protocol Improvement Techniques Over Space-Based Transmission Media, Joseph M. Lawson

Theses and Dissertations

The purpose of this study was to assess the throughput improvement afforded by the various TCP optimization techniques, with respect to a simulated geosynchronous satellite system, to provide a cost justification for the implementation of a given enhancement technique. The research questions were answered through model and simulation of a satellite transmission system via a Linux-based network topology; results of the simulation were analyzed primarily via a non-parametric method to ascertain performance differences between the various TCP optimization techniques. It was determined that each technique studied, which included the Space Communication Protocol Standard-Transport Protocol (SCPS-TP), window scale, selective acknowledgements (SACKs), …

Contingency Planning And An Air Force Space Command Information System, Kaylin Freedman, Michael R. Grimaila

Faculty Publications

No abstract provided.

Managing The Integration Of Space And Information Operations, Daniel F. Gottrich, Michael R. Grimaila

Faculty Publications

No abstract provided.

Improving Efficiency In Engineering Design Using Augmented D-Optimal Designs 'Synthetic Jet' Design Optimization Study, Fatih Erdogan

Engineering Management & Systems Engineering Theses & Dissertations

The purpose of this thesis is to study the efficiency of several "design of experiments" (DOE) approaches used for the analysis and optimization of engineering designs. A literature review is conducted to study various "design of experiments" methods and the advantages and limitations of each method are discussed.

As an application, Augmented D-Optimal designs are utilized for a design study of 'synthetic jet'.

With the objective of improving efficiency and providing a minimum point experimental design model, computer-aided D-optimal method is preferred for this study. For setting up the design of the experiments and for performing the analysis of results, …

Development Of Autonomous Unmanned Aerial Vehicle Platform: Modeling, Simulating, And Flight Testing, Nidal M. Jodeh

Theses and Dissertations

The Advanced Navigation Technology (ANT) Center at the Air Force Institute of Technology (AFIT) conducts extensive research in advanced guidance, navigation, and control to exploit the full potential of autonomous Unmanned Aerial Vehicles (UAV). The research in this thesis describes a UAV research platform developed to support the ANT Center's goals. This platform is now the bedrock for UAV simulation and local flight test at AFIT. The research has three major components. The first component is development of a physical, inertial, and aerodynamic model representing an existing aircraft. A systematic analysis of the airframe leads to a complete geometric, inertial, …

A Game Theory Approach To Constrained Minimax State Estimation, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

This paper presents a game theory approach to the constrained state estimation of linear discrete time dynamic systems. In the application of state estimators, there is often known model or signal information that is either ignored or dealt with heuristically. For example, constraints on the state values (which may be based on physical considerations) are often neglected because they do not easily fit into the structure of the state estimator. This paper develops a method for incorporating state equality constraints into a minimax state estimator. The algorithm is demonstrated on a simple vehicle tracking simulation.

Introduction To Product Design And Innovation: A Cross Disciplinary Mini Curriculum, Patricia Backer, Seth Bates

Faculty Publications

For the past two years, faculty at San Jose State University (SJSU) have implemented a three- semester minicurriculum in Product Design and Manufacturing. The project follows the Project- Based Learning (PBL) model and is central to the Certificate Program in Product Design in the Mechanical Engineering Department, the Manufacturing Systems concentration in the Department of Aviation and Technology, and the Industrial Design Program in the School of Art and Design. Students in the three courses in the minicurriculum face design challenges while being instructed about the constraints of manufacturability. In each course, students develop three to four products. All products …

Stochastic Capability Models For Degrading Satellite Constellations, Cole W. Gulyas

Theses and Dissertations

This thesis proposes and analyzes a new measure of functional capability for satellite constellations that incorporates the instantaneous availability and mission effectiveness of individual satellites. The capability measure yields a continuous score between zero and one accounting for the degree to which the constellation meets operational requirements. The measure is computed from an average of satellite capabilities, composed of the product of the satellite's instantaneous availability and value score. Instantaneous availability is acquired by modeling the satellite degradation status as either a time-homogenous, continuous-time Markov chain (CTMC) if it possesses functions with exponential lifetime distributions, or as a time-homogenous, semi-Markov …

An Approach For Optimizing The On-Orbit Servicing Architecture For The Space-Based Radar Constellation, Michael L. Mcconnell

Theses and Dissertations

Satellite systems, once operational, are essentially a consumable item with no capacity to maintain, repair, or upgrade them while on-orbit. In order to avoid having to replace costly space assets, the Defense Advanced Research Projects Agency (DARPA) and Air Force Space Command (AFSPC) are looking to developing programs to provide an on-orbit servicing capability for future satellite systems under development, such as the Space-Based Radar (SBR) system. DARPA and AFSPC are studying on-orbit servicing using the Orbital Express platform as part of an Analysis of Alternatives for the SBR program. Like their satellite clients, on-orbit servicing assets are expected to …

Results Of An Interlaboratory Study Of The Astm Standard Test Method For Tensile Properties Of Polymer Matrix Composites D 3039, Margaret Pinnell, Richard Fields, Ronald Zabora

Mechanical and Aerospace Engineering Faculty Publications

An investigation was conducted on the ASTM Standard Test Method for Tensile Properties of Polymer Matrix Composites (D 3039). This investigation consisted of both preliminary testing and an interlaboratory test program. Information generated from preliminary testing was used to determine the effects of various parameters and to optimize the interlaboratory test plan and test protocol. The interlaboratory study portion of this investigation was conducted on six composite material systems in a variety of lay-up configurations. The number of participating labs ranged from five to nine depending on the material type. Precision statistics were determined for the ASTM D 3039 standard …

Performance Analysis And Validation Of A Recoverable Flight Control System In A Simulated Neutron Environment, Hong Zhang, W. Steven Gray, Oscar R. Gonzalez

Electrical & Computer Engineering Faculty Publications

This paper introduces a class of stochastic hybrid models for the analysis of closed-loop control systems implemented with NASA's Recoverable Computer System. Such Recoverable Computer Systems have been proposed to insure reliable control performance in harsh environments. The stochastic hybrid models consist of either a stochastic finite-state automaton or a finite-state machine driven by a Markov input, which in turn drives a switched linear discrete-time dynamical system. Their stability and output tracking performance are analyzed using an extension of the existing theory for Markov jump-linear systems. For illustration, a stochastic hybrid model is used to calculate the tracking error performance …

Aeroelastic Analysis Of A Flexible Membrane Wing, Isaac Nguri Wanjohi

Master's Theses - Daytona Beach

The focus of this research proposal is the investigation of the aeroelastic effects of a flexible lift augmentation system (LAS) wing. This research involves characterization of the forced vibration response of a wing appendage used to augment short field take off and landing (STOL) operations.

Although flutter theory is now well understood, the LAS presents the complications of a highly deformable airfoil shape as well as larger structural damping values compared to metal wings.

The proposed research will involve derivation of the equations of motion aided by experimental data from nodal excitation of the wing; stiffness and rigidity modeling from …

Modeling Launch Vehicle Success Using Artificial Neural Networks, Jennifer A. Schuck

Master's Theses - Daytona Beach

Expendable launch vehicles in the United States currently have a reliability of 92%. The failures that do occur cost millions of dollars in spacecraft replacement, lost revenue, and other expenses. These costs are passed on in higher insurance rates and launch vehicle price. If the launch outcome of the launch vehicles could be better predicted, the overall cost of launching payloads into space would decrease. This study used artificial neural networks to model the overall launch outcome of a launch vehicle so that the results of a launch could be predicted. Two neural network architectures--MLP and fuzzy ARTMAP--were trained on …

Data Smoothing And Interpolation Using Eighth-Order Algebraic Splines, Daniel J. Simon

Electrical and Computer Engineering Faculty Publications

A new type of algebraic spline is used to derive a filter for smoothing or interpolating discrete data points. The spline is dependent on control parameters that specify the relative importance of data fitting and the derivatives of the spline. A general spline of arbitrary order is first formulated using matrix equations. We then focus on eighth-order splines because of the continuity of their first three derivatives (desirable for motor and robotics applications). The spline's matrix equations are rewritten to give a recursive filter that can be implemented in real time for lengthy data sequences. The filter is lowpass with …

Analytical Results For A Single-Unit System Subject To Markovian Wear And Shocks, Daniel E. Finkelstein

Theses and Dissertations

This thesis develops and analyzers a mathematical model for the reliability measures of a single-unit system subject to continuous wear due to its operating environment and randomly occurring shocks that inflict a random amount of damage to the unit. Assuming a Markovian operating environment and shock arrival mechanism, Laplace-Stieltjes transform expressions are obtained for the failure time distribution and all of its moments. Moreover, an analytical expression is derived for the long-run availability of the single-unit system when it is subject to an inspect-and-replace maintenance policy. The analytical results are illustrated, and their results compared with those of Monte Carlo-simulated …

Systems-Level Feasibility Analysis Of A Microsatellite Rendezvous With Non-Cooperative Targets, Allen R. Toso

Theses and Dissertations

The feasibility of using a microsatellite to accomplish an orbital rendezvous with a noncooperative target was evaluated. This study focused on identifying and further exploring the technical challenges involved in achieving a noncooperative rendezvous. A system engineering analysis and review of past research quickly led to a concentration on the guidance, navigation, and control elements of the microsatellite operation. The integration of control and orbit determination algorithms was investigated. A simple yet robust solution could not be found to meet reasonable rendezvous criteria, using essentially off-the-shelf technology and algorithms. System feasibility has been assessed to have a low probability in …

Reusable Space Vehicle Ground Operations Baseline Conceptual Model, Dennis R. Maynard, Patricia Pettit

Theses and Dissertations

Modeling efforts for future space operation vehicles at the United States Air Force Research Labs Air Vehicles Directorate have been focused towards the in-flight mission. To better serve the research and development effort, a simulation of the ground operations is required allowing for trade-offs within turnaround operations and between the components that drive those procedures. However, before a simulation can be developed a conceptual model must be generated to guide the model building process. This research provides a baseline conceptual model for reusable space vehicles based on the space shuttle as the only operational vehicle of its kind. The model …

Optimal Constellation Design For Orbital Munitions Delivery System, Jason Anderson

Theses and Dissertations

Rather than delivering conventional munitions through the airspace of uncooperative nations, a constellation of space-stored weapons could potentially target any point on the Earth and arrive within the time it takes to de-orbit and re-enter through the atmosphere. The research involves applying the dynamics of atmospheric re-entry to a Common Aero Vehicle (CAV) and defining a footprint of attainable touchdown points. The footprint is moved forward to create a swath representing all the possible touchdown points in a 90 minute window. A nominal constellation of CAVs is established using a streets of coverage technique, and both analytic studies and numeric …

Calibrating Expert Assessments Of Advanced Aerospace Technology Adoption Impact, Bruce A. Conway

Engineering Management & Systems Engineering Theses & Dissertations

This dissertation describes the development of expert judgment calibration methodology as part of elicitation of the expert judgments to assist in the task of quantifying parameter uncertainty for proposed new aerospace vehicles. From previous work, it has been shown that experts in the field of aerospace systems design and development can provide valuable input into the sizing and conceptual design of future space launch vehicles employing advanced technology. In particular (and of specific interest in this case), assessment of operations and support cost implications of adopting proposed new technology is frequently asked of the experts. Often the input consisting of …

Multimission Aircraft Design Study, Payload, Ahmet Kahraman

Theses and Dissertations

It is proposed that a Multi-Mission Aircraft (MMA) be prepared to combine some or all the functions of the aging AWACS, JSTARS, RIVET JOINT, COMPASS CALL, and AECCC fleet. Three different thesis studies have been developed by three Air Force Institute of Technology GSE students to show the feasibility of replacing the current aging fleet with one or more MMA platforms. This is the thesis in which the payload issuer have been examined. Within this thesis, two different alternative architectures, which are One Tail Number and Different Tail Numbers including nine different configurations, have been considered. Estimated payload characteristics of …

Multimission Aircraft Design Study: Electromagnetic Compatibility, Jenna M. Davis

Theses and Dissertations

The multi-mission aircraft (MMA) technical feasibility study looked at the replacement of the aging fleet of C-135 and C-130 theater based command & control (C2) and intelligence, surveillance and reconnaissance (ISR) fleet. It is proposed that the MMA be out-fitted to combine some or all the functions of existing AWACS, JSTARS, RIVET JOINT, COMPASS CALL, and ABC CC platforms. It would also have links to other manned or unmanned ISR aircraft, as well as satellites. The objective of the proposed design study is to examine the technical risks involved in combining multiple functions onto one aircraft that currently reside on …