Mission Automation for "A Train" Correlative Measurements

Simulation of Modal Vibration Pattern Variations Due to Gyroscopic Effects in an Active Vibration-Controlled Structure

Aerospace Applications of Network Centric Computing

Better - 50X Faster - $12M Cheaper - An Example from ISS GN&C Systems Flight Readiness Certification

GN&C Technology Needed to Achieve Pinpoint Landing Accuracy at Mars

Fabrication and Measurement of an IC-Compatible GHz-Range Piezoelectric Longitudinal Bar Resonator

Candler, R.N. et al.

Reduction in Thermoelastic Dissipation in Micromechanical Resonators by Disruption of Heat Transport

Non-Gaussian Robust Matched Subspace Detectors and Signal Design Analysis for a Separable Class of Subspaces

Non-Gaussian Subspace Learning in the Presence of Interference

Subspace Learning in Non-Gaussian Log-Concave Noise

Micron-gap ThermoPhotoVoltaics (MTPV)

MEMS Arrays for Label-Free Sensing of Biomolecules

Modeling and Control of Micro Calorimeter

 XNsim Extensible Network Simulation

Fault-Tolerant Avionics Systems

Personal Navigation for the Warfighter

MEMS Inertial Technology: A Short Course

Draper Simulation Analysis Tool (DSAT): Graphical Object Simulation Techniques and Tools for Simulink

A MEMS-Based Renal Replacement System

Low-Cost IMU Technology

Kourepenis, A. et al.

MEMS Gyroscopes and Accelerometers : A Review of Current Designs and Fabrication Approaches

Autoregressive Modeling of Analytical Sensor Data Can Yield Classifiers in the Predictor Coefficient Parameter Space

Non-Invasive Breath Analysis Using Field Asymmetric Ion Mobility Spectrometry and Bioinformatics Pattern Recognition

CMOS-Compatible Erbium Coupled Si Nanocrystal Thin Films For Microphotonics

Optical Gain in Strongly Coupled Erbium-Doped Silicon Nanocrystals Annealed at Low Temperatures

LeBlanc, J. et al.

Photon Band-Gap Properties and Omnidirectional Reflectance in Si/SiO2 Thue-Morse Quasicrystals

Trajectory Interpolation for Parametrized Maneuvering and Flexible Motion Planning of Autonomous Vehicles

Omnidirectional Reflectance and Optical Gap Properties of Si/SiO2 Thue-Morse Quasicrystals

An Autonomous Threat Evasion Response Algorithm for Unmanned Air Vehicles During Low Altitude Flight

Hybrid Optimal Control Framework for Mission Planning

Rapid Trajectory Optimization of Multi-Agent Hybrid Systems

Satellite Constellation Design for a Mid-Course Ballistic Missile Intercept

Light Emission from Silicon Nanocrystals (Si-nc's) in SiOx Films Prepared by RF Magnetron Sputtering

Weinberg, E.J. et al.

Design and Fabrication of a Constant Shear Microfluidic Network for Tissue Engineering

Fluid Effects in Vibrating Micromachined Structures

Hierarchical Planning for Large Numbers of Unmanned Vehicles

11th Saint Petersburg International Conference on Integrated Navigation Systems

Saint Petersburg International Conference on Integrated Navigation Systems. 11th. Held in Russia, St. Petersburg, 05/24/2004 to 05/26/2004. (Draper Report no. CSDL-2004-040)

Subjects: NAVIGATION SYSTEMS, INERTIAL SYSTEMS, INERTIAL SENSORS, INTEGRATED SYSTEMS, SATELLITES

Abramson, M.; Carter, D.; Collins, B.; Kolitz, S.; Scheidler, P.; Strauss, C.

Mission Automation for "A Train" Correlative Measurements

Earth Science Technology Conference. Held in Palo Alto, CA, 06/22/2004 to 06/24/2004. Sponsored by: NASA. (Draper Report no. P-4243)

Abstract: Observing System testbed to utilize near-real-time cloud cover data from the Air Force Weather Agency's Joint Army Air Force Weather Information Network World-Wide Merged Cloud Analysis. The cloud data are used as input in the simulated tasking of the TES and HIRDLS instruments on Aura, with the objective of achieving increased science value of the observation data. The cloud cover data include 1) hourly updates of current conditions and 2) forecast updates provided every 6 hours for up to 30 hours in the future. The cloud cover contains information on up to four cloud layers for each of 1024 x 1024 cells per hemisphere specified in a polar stereographic grid. We describe models we have developed of the observation-taking processes used by Aura's HIRDLS and TES instruments. We model each HIRDLS mode as a fixed-scan pattern, i.e., a sequence of azimuth and elevation values. We model TES as a scan of a ground area, using a latitude and longitude viewpoint. We calculate the science value of sensor observations as a function of the target, the sensor line of sight and field of view, and the cloud cover. The observation science value function is used as input in the optimization-based planning function of the Earth Phenomena Observing System (EPOS) mission planner, which generates plans that could be used in HIRDLS' Selected Targets Mode and TES' Special Product Mode. These modes could be invoked during times the instruments are not in standard collection modes, e. g., HIRDLS' Global Observing Mode and TES' Global Survey Mode.

Subjects: EARTH PHENOMENA OBSERVING SYSTEM (EPOS), MISSION AUTOMATION, CLOUD COVER

Antkowiak, B.M.

Simulation of Modal Vibration Pattern Variations Due to Gyroscopic Effects in an Active Vibration-Controlled Structure

Virtual Product Development Conference. Held in Huntington Beach, CA, 10/18/2004 to 10/20/2004. Sponsored by: MSC Software. (Draper Report no. P-4226)

Abstract: A method to model and simulate an active vibration-controlled structure while subject to external inertia and gyroscopic effects is presented. Finite element is used to model the structure in detail, and modal reduction is used to reduce the model size. The finite-element model is also used to extract a modal reduced gyroscopic matrix [G]. This rate-dependent matrix is then included into the dynamics model. By reformulating the model in state-space, a rotational rate-dependent dynamics matrix [A], drive actuator matrix [B], and sensor matrix [C] are developed. These matrices can then be readily integrated into a closed-loop control system. This method is demonstrated on a hemispherical resonating gyroscopic where the modal patterns are influenced by the Coriolis forces from an externally applied rotation. MSC/PATRAN is used to model the significant components using solid geometry, and the element analysis is used to construct the state space dynamics matrices [A], [B], and [C], including the modally reduced gyroscopic matrix [G]. These matrices are then assembled and used in a closed-loop feedback control in MATLAB/SIMULINK. The vibrating gyroscope is then subjected to external inertial and rotation loads. The inclusion of the gyroscopic loads is verified by observing the shift in the modal pattern due to a given rotational input, and the results are compared to measured values.

Subjects: ACTIVE VIBRATION, VIBRATION-CONTROLLED STRUCTURE, SIMULATIONS, FINITE-ELEMENT MODELS (FEM)

Bedrossian, N.; Harrison, J.

Aerospace Applications of Network Centric Computing

Modeling and Simulation Technologies Conference & Exhibit. Held in Reston, VA, 08/16/2004 to 08/19/2004. Sponsored by: AIAA. (Draper Report no. P-4238)

Abstract: This paper describes the use of Network Centric Computing ( NCC) in aerospace applications. NCC is a set of networked computers that are used for resource sharing and coordinated problem solving. Two categories of NCC, internet computing, and distributed simulation, are described with example applications. Internet computing describes centralized applications accessed by geographically distributed users. In this category, two internally developed software products are reviewed: eSim and VSSim. Distributed simulation involves geographically distributed software subsystems, which are assembled into complete simulations over a network by geographically distributed users. In this category, an internally-developed software product, XNsim, is reviewed.

Subjects: AEROSPACE APPLICATIONS, EXTENSIBLE NETWORK SIMULATION (XNISM), NETWORK CENTRIC COMPUTING

Bedrossian, N.

Better - 50X Faster - $12M Cheaper - An Example from ISS GN&C Systems Flight Readiness Certification

Modeling and Simulation Technologies Conference & Exhibit. Held in Providence, RI, 08/16/2004 to 08/19/2004. Sponsored by: AIAA. (Draper Report no. P-4237)

Abstract: This paper describes the systems engineering approach, claimed to be " better, faster, cheaper," used for Flight Readiness Certification of the International Space Station Guidance Navigation & Control systems. Using screening analysis, substantial productivity gains have been obtained during the past 6 years. Screening analysis and associated tools have provided the order-of-magnitude improvement compared with an all-legacy high-fidelity simulation analysis approach. Based on actual expenditures and by costing the screening effort using simulation analysis expenditures, savings of $12,000,000 have been achieved. By using linear time-invariant flex structural models, automated simulation configuration, analysis, and documentation features, execution speed is improved 50 times. Risk reduction is obtained due to confidence in predicted system behavior in the presence of uncertainties. The key enabling feature is identified as change of approach in how the task is performed, both in systems engineering approach and computational infrastructure. It is also shown that confidence is both cheaper and faster to obtain than accuracy, and that accuracy does not correspond to confidence.

Subjects: FLIGHT READINESS, CERTIFICATION, INTERNATIONAL SPACE STATION (ISS), GUIDANCE NAVIGATION AND CONTROL (GN&C), RISK MANAGEMENT

Brady, T.; Buckley, S.; Tillier, C.

Ground Validation of the Inertial Stellar Compass

Aerospace Conference. Held in Big Sky, MT, 03/06/2004 to 03/13/2004. Sponsored by: IEEE. (Draper Report no. P-4195)

Abstract: The Inertial Stellar Compass ( ISC), under development at Draper Laboratory, provides spacecraft attitude determination to 0.1-degree accuracy using just 3.5 W of power. This paper describes the process of validating the performance of the instrument on the ground prior to characterizing it on orbit. Starting with subsystem-level testing of the ISC's active pixel sensor camera and MEMS (Microelectromechanical System) 3-axis gyro board, we describe the operations leading up to integrated system testing of the camera and gyro sensor outputs, which are combined to provide a robust attitude solution over a wide range of operating conditions. Under the guidance of NASA's New Millennium Program, the ground validation process, which will be followed by an on-orbit demonstration, will make feasible a new class of low-power, integrated attitude sensors for small spacecraft.

Subjects: INERTIAL STELLAR COMPASS (ISC), MICROELECTROMECHANICAL SYSTEM (MEMS), ATTITUDE DETERMINATION

Brand, T.; Fuhrman, L.; Geller, D.; Hattis, P.; Paschall, S.; Tao, Y.C.

GN&C Technology Needed to Achieve Pinpoint Landing Accuracy at Mars

Astrodynamics Specialist Conference. Held in Providence, RI, 08/16/2004 to 08/19/2004. Sponsored by: AIAA. (Draper Report no. P-4240)

Abstract: The desire to achieve pinpoint landing accuracies of tens to hundreds of meters for future Mars surface missions has prompted a study of the technology that will be needed to make such landings possible. The Entry, Descent, and Landing (EDL) phases of such a mission were studied in detail in terms of contributions of various error sources to landing accuracy and control authority needed in each phase to remove errors. A broad variety of landing technologies were considered, and the field narrowed to focus on a modified version of the typical current landing sequence implementation (upgraded aeroshell, parachute, and propulsive lander with navigation aiding sensors), as well as one possible new decelerator technology (Hypercone) that could enable landings at very high (2.5 km above mean surface centroid) altitudes. It was found that incremental improvements to current technologies are required for each phase (aeroshell, parachute, and terminal descent) of the EDL sequence, and that new navigation sensor technology (navigation aiding sensors) is needed to meet the study parameters for payload delivered to target. The study parameters included a usable delivered payload of 1000 kg and an entry vehicle configuration that must fit inside a Mars Science Laboratory-class biconic aeroshell with an assumed system mass of 2400 kg at the entry interface.

Subjects: GUIDANCE NAVIGATION AND CONTROL (GN&C), MARS SURFACE, MARS LANDING, ENTRY, DESCENT, LANDING (EDL)

Carter, D.J.D.; Kang, J.; White, D.; Duwel, A.E.

Fabrication and Measurement of an IC-Compatible GHz-Range Piezoelectric Longitudinal Bar Resonator

Transducers Research Foundation. Held in Hilton Head, SC, 06/06/2004 to 06/10/2004. (Draper Report no. P-4199)

Abstract: We report on the fabrication and measurement of an acoustic MEMS resonator designed to operate in air with high Q and low impedance in the ~50-MHz to 2-GHz frequency range. The resonator is a longitudinal-mode, piezoelectrically-actuated bar consisting of a sandwich of metal/aluminum nitride (AlN)/metal (Figure1). It is suspended above a gap by two tethers. The device is a one-port component, where top and bottom metal electrodes both actuate the resonator and sense its response. Since the longitudinal-mode frequency is set lithographically by the lateral bar dimensions, a wide range of resonator frequencies can be created on a single chip. This first set of fabricated devices had resonator lengths ranging from 3 to 30 microns, corresponding to frequencies from 100 MHz to 1.3 GHz, on a single wafer. Device processing is IC compatible, offering the potential for integration in transceiver applications. Figure 2 shows an overview of the process flow. Device fabrication starts with a molybdenum (Mo)/AlN bilayer deposited in-situ using sputtering and reactive sputtering. The resonator stack structure is patterned by top-metal (nickel (Ni)) liftoff, wet etching of the piezoelectric AlN, and reactive ion etching (RIE) of the bottom metal (Mo). Additional etch steps pattern the proper electrical circuit. The release of the structure uses the patterned Mo/AlN/Ni stack as an etch mask for the SiO2 release layer. Figure 3 shows a scanning- electron micrograph of the etched and released resonator. Notable features of the fabrication process include tradeoffs among device electrical characteristics, IC-compatible processing, and piezoelectric film growth requirements dictated materials selection. The choice of molybdenum, aluminum nitride, and nickel required a unique set of selective etch chemistries. AIN wet etching in AZ400k resist developer with a Ni etch mask was seemingly self-limiting a fixed sidewall angle; over etching by a factor of ~50 did not deteriorate the pattern. A scanning-electron micrograph of the etched stack structure is shown in Figure 4.  As shown in Figure 1, the resonator structure is a small (few micron square) parallel plate capacitor suspended above the substrate by narrow tethers. For optimal device response, it was necessary to minimize parasitic capacitances from the tethers by allowing the top and bottom metal to overlap only at the resonator. A XeF2 undercut etch was used to pattern the bottom molybdenum layer in the tether. The small device size requires precise alignment between the device, the tethers, and the supports. The process incorporates all of these alignments into the first mask level, and both the device definition and release are self-aligned. Testing is conducted at the wafer level, in air, at room temperature, using commercially available probe tips and an HP Network Analyzer. The device is wired in a series configuration for two-port measurements. Figure 5 shows test data on individual resonators and a plot of frequency vs. device length, indicating that scaling with length with the same scaling factor as our calculations.

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), ACOUSTIC MEASUREMENTS, ACOUSTIC RESONATORS, PIEZOELECTRICITY

Candler, R.N.; Hopcroft, M.; Park, W.T.; Chandorkar, S.A.; Yama, G.; Goodson, K.E.; Varghese, M.; Duwel, A.E.; Partridge, A.; Lutz, M.; Kenny, T.W.

Reduction in Thermoelastic Dissipation in Micromechanical Resonators by Disruption of Heat Transport

Hilton Head 2004: A Solid State Sensor, Actuator, and Microsystems Workshop. Held in Hilton Head, SC, 06/06/2004 to 06/10/2004. Sponsored by: Transducer Research Foundation, Inc. (Draper Report no. P-4225)

Abstract: Micromechanical resonators have been fabricated with a novel geometry designed to disrupt thermoelastic dissipation (TED), which is heat flow that can limit the quality factor, Q. Finite-element simulations were used to design resonators with heat flow-interrupting slits that have achieved Q's higher than a simple beam achieves and higher than a simplistic application of Zener theory predicts. The new structures have a Q as much as 4X the value of those without the new geometry, 40,000 as compared with 10,000 for a ~550-kHz resonator. This result shows the necessity of modeling the complex interaction between the thermal and mechanical modes, and demonstrates a tool to engineer specific Q values for micromechanical resonators.

Subjects: MICROMECHANICAL RESONATORS, THERMOELASTICITY, HEAT FLOW

Curey, R.K.; Ash, M.E.; Thielman, L.O.; Barker, C.H.

Proposed IEEE Inertial Systems Terminology Standard and Other Inertial Sensor Standards

Position Location and Navigation Symposium (PLANS). Held in Monterey, CA, 04/26/2004 to 04/29/2004. Sponsored by: IEEE/AESS. (Draper Report no. P-4127)

Abstract: A new inertial systems terminology standard is being developed by the IEEE/AESS Gyro and Accelerometer Panel for consideration by the IEEE Standards Board as IEEE Std 1559. It is intended to be a companion to IEEE Std 528- 2001, IEEE Standard for Inertial Sensor Terminology. These two documents as well as IEEE standards that have been published for single- and two-degree-of-freedom spinning wheel gyros, laser gyros, interferometric fiber-optic gyros, Coriolis vibratory gyros (including MEMS gyros), angular accelerometers, linear accelerometers, accelerometer centrifuge testing, and an inertial sensor test equipment and analysis document are discussed in this paper.

Subjects: INERTIAL SYSTEMS, STANDARDIZED TERMINOLOGY, INERTIAL SENSORS

Desai, M.; Mangoubi, R.

Non-Gaussian Robust Matched Subspace Detectors and Signal Design Analysis for a Separable Class of Subspaces

Array and Multichannel Signal Processing Workshop. Held in Barcelona, Spain, 07/18/2004 to 07/21/2004. Sponsored by: IEEE. (Draper Report no. P-4211)

Abstract: This paper introduces a new class of subspaces, denoted separable subspaces, that enable the derivation of computationally efficient expressions for robust matched filter detectors for the family of Generalized Gaussian (GG) density functions. These generalized likelihood ratio detectors are robust to interference whose subspace may or may not be known or learned. The detectors are generalizations of the X2, and t or F statistics used when the noise is assumed to have a Gaussian density, also a member of the GG family. This paper also describes how arbitrary subspaces can be approximated by the newly introduced separable ones should it be advantageous to do so; separable subspaces therefore make it possible to discretize the space. The computationally efficient expressions for the detectors enable the performance analysis for signal design when the basis for the separable subspaces consists solely of binary valued elements. This class, which includes the Haar basis functions, has been shown to be applicable to functional MRI detection problems.

Subjects: NON-GAUSSIAN, SUBSPACE DETECTORS, GAUSSIAN, SIGNAL ANALYSIS

Desai, M.; Mangoubi, R.

Non-Gaussian Subspace Learning in the Presence of Interference

Sensors and Actuators A- Physical. 3rd. Held in Barcelona, Spain, 07/18/2004 to 07/21/2004. Sponsored by: IEEE. (Draper Report no. P-4210)

Abstract: We consider the problem of subspace learning in the presence of interference and generalized Gaussian noise, two realistic scenarios for many applications. We also explore learning in the context of a non-Euclidean generalization of the Courant-Fisher minmax characterization. Implications for learned subspace properties in the presence of Laplacian noise are discussed as well.

Subjects: GAUSSIAN, NON-GAUSSIAN, SUBSPACE LEARNING

Desai, M.; Mangoubi, R.

Subspace Learning in Non-Gaussian Log-Concave Noise

Asilomar Conference on Signals, Systems, Computers. 38th. Held in Pacific Grove, CA, 11/07/2004 to 11/10/2004. Sponsored by: IEEE. (Draper Report no. P-4298)

Abstract: We consider subspace learning from measurements corrupted by log-concave random noise. The class includes, but is not limited to, Generalized Gaussian (GG) noise with shape parameter greater than or equal to unity, log-concave Spherically Invariant Random Processes (SIRPs), and their generalizations to Norm Invariant Random Processes (NIRPs). The noise properties need not be constant in the independent time and/or space variable. Necessary conditions are derived and they are computationally simpler when factorability properties are applicable, as is the case with GGs, SIRPs, and NIRPs when the signal space is one-dimensional.

Subjects: SUBSPACE LEARNING, NON-GAUSSIAN, RANDOM NOISE, GENERALIZED GAUSSIAN, SPHERICALLY INVARIANT RANDOM PROCESSES (SIRP), NORM INVARIANT RANDOM PROCESSES (NIRP)

DiMatteo, R.; Greiff, P.; Meulenberg, D.; Brown, E.; Carlen, E.; Kaiser, K.; Finberg, S.; Nguyen, H.; Seltzer, D.; Azarkevich, J.; Baldasaro, P.; Beausang, J.; Danielson, L.; Dashiell, M.; DePoy, D.; Ehsani, H.; Topper, W.; Rahner, K.; Siergiej, R.

Micron-gap ThermoPhotoVoltaics (MTPV)

Thermophotovoltaic Generation of Electricity. 6th. Held in Freiburg, Germany, 06/14/2004 to 06/16/2004. Sponsored by: AIP. N738. 08/2004. p. 42-51. (Draper Report no. P-4242)

Abstract: This paper discusses advances made in the field of Micron-gap ThermoPhotoVoltaics (MTPV). Initial modeling has shown that MTPV may enable significant performance improvements relative to conventional far-field TPV. These performance improvements include up to a 10x increase in power density, 30% to 35% fractional increase in conversion efficiency or alternatively, reduced radiator temperature requirements to as low as 550 deg C. Recent experimental efforts aimed at supporting these predictions have successfully demonstrated that early current and voltage enhancements could be done repeatedly and at higher temperatures. More importantly, these efforts indicated that no unknown energy transfer process occurs reducing the potentially utility of MTPV. Progress has been made by running tests with at least one of the following characteristics relative to the MTPV results reported in 2001: Tests at over twice the temperature (900 deg C). Tests at 50% smaller gaps (0.12 micron). Tests with emitter areas from 4 to 100 times larger (16 mm2 to 4 cm2). Tests with over 20x reduction in parasitic spacer heat flow. Remaining fundamental challenges to realizing these improvements relative to the recent breakthroughs in conventional far-field TPV include reengineering the photovoltaic (PV) diode filter and emitter system for MTPV, and engineering devices and systems that can achieve submicron vacuum gaps between surfaces with large temperature differences.

Subjects: MICRON-GAP THERMOPHOTOVOLTAICS (MTPV), PHOTOVOLTAIC CONVERSION

Dubé, C.E.; Weinberg, M.S.; Carlen, E.T.; Mescher, M.J.; Duwel, A.; Baldwin, K.; Sitomer, J.L.

MEMS Arrays for Label-Free Sensing of Biomolecules

Society for Experimental Mechanics. 5th. Held in Costa Mesa, CA, 06/07/2004 to 06/10/2004. Sponsored by: SEM. (Draper Report no. P-4203)

Abstract: Three different label-free biosensors fabricated using microelectromechanical systems (MEMS) technology are presented. The flexural plate-wave (FPW), capacitive surface stress (CSS), and microcalorimeter (µCal) sensors all share two basic elements: a receptor for molecular recognition and a physicochemical transducer. Since the receptor is coupled directly to the physical transducer, all three devices are label-free sensing systems. The FPW resonating sensor measures the mass of affinity-captured molecules and organisms using the change in resonant frequency of a piezoelectric actuated flexural plate. The CSS sensor measures the capacitance variation between a plate and a diaphragm that deflects under the surface stress induced by ligand-receptor binding process. The µCal sensor detects and analyzes the energetics of ligand-receptor binding by measuring the heat of reaction using a resistive temperature detector on a thermally-isolated micro hotplate. The design, fabrication, and performance of the three sensors are presented.

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), BIOSENSORS, BIOMOLECULES

Dubé, C.; Mescher, M.; Duwel, A.; Baldwin, K.; King, T.

Modeling and Control of Micro Calorimeter

Workshop on Control and System Integration of Micro and Nano-scale Systems. Held in Washington, DC, 03/29/2004 to 03/30/2004. Sponsored by: NSF. (Draper Report no. P-4229)

Subjects: MODELING, CALORIMETRY, TEST AND CONTROL, MICROELECTROMECHANICAL SYSTEM (MEMS), BIOLOGICAL SYSTEMS

Flannery, E.; Novotny, J.; Karpov, I.; Zhang, C.; Bedrossian, N.

XNsim Extensible Network Simulation

International Symposium on Collaborative Technologies and Systems. Held in Orlando, FL, 01/19/2004 to 01/24/2004. (Draper Report no. P-4183)

Abstract: In this paper, a dynamically scalable distributed simulation framework called eXtensible Network Simulation (XNsim) is presented. With this approach, a complete simulation can be assembled from shared component subsystems written in different formats, which run on different computing platforms, with different sampling rates, in different geographic locations, and over single/ multiple networks. The software uses a peer-to-peer communication architecture. An example is presented to illustrate its features and capabilities. Further information about XNsim is available at the product homepage, http:// www. xnsim. com/.

Subjects: EXTENSIBLE NETWORK SIMULATION (XNISM), DISTRIBUTED SIMULATIONS, INTERNET

Hammett, R.C.

Fault-Tolerant Avionics Systems

Digital Avionics Systems Conference. Held in Salt Lake City, UT, 10/24/2004 to 10/28/2004. Sponsored by: AIAA/IEEE. (Draper Report no. P-4266)

Subjects: FAULT-TOLERANT SYSTEMS, AVIONICS SYSTEMS, TUTORIALS

Holmes, S.; Kourepenis, A.; Sherman, P.; Girolamo, H.; Zimmer, G.; Sokolowski, S.

Personal Navigation for the Warfighter

Joint Navigation Conference . Held in Las Vegas, NV, 05/03/2004 to 05/06/2004. Sponsored by: JSDE/JNC. (Draper Report no. P-4233)

Subjects: PERSONAL NAVIGATION, WARFIGHTER, MICROELECTROMECHANICAL SYSTEM (MEMS)

Hopkins, R.

MEMS Inertial Technology: A Short Course

Plans 2004. Held in Monterey, CA, 04/26/2004 to 04/29/2004. Sponsored by: IEEE. (Draper Report no. P-4232)

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), INERTIAL TECHNOLOGY, INERTIAL SENSORS

Jackson, M.C.; McDonald, R.D.

Draper Simulation Analysis Tool (DSAT): Graphical Object Simulation Techniques and Tools for Simulink

Modeling and Simulation Technologies Conference and Exhibit. Held in Providence, RI, 08/16/2004 to 08/19/2004. Sponsored by: AIAA. (Draper Report no. P-4248)

Abstract: A graphical object-based approach to simulation design is presented using Simulink. High-level, drag-and-drop simulation objects such as satellites, boosters, and planets are created using structured data and layers of subsystem masks. These objects may be replicated with no manual internal changes, allowing easy instantiation of multiple vehicles. Each object creates its own set of structured default data when it is introduced to the simulation. Structured initialization parameters reduce workspace clutter by combining parameters into hierarchical substructures corresponding to each simulation object and subsystem. Rapid construction of spacecraft simulations is demonstrated using a library of high-level graphical objects. The library also contains mix and match subsystem objects, allowing the designer to start with a vehicle "chassis" and add sensors, effectors, and guidance, navigation, and control (GN&C) laws - either from the library, or custom developed. Automated, graphical S-Function development tools are also discussed. These tools create subsystem objects that can utilize structured data as parameter inputs. Graphical initialization interfaces may also be added to the simulation via drag-and-drop from the library. An interface to Satellite Tool Kit (STK) that allows automatic instantiation of STK scenario objects from Simulink is also presented. The techniques for architecting these graphical, object-based simulations are also detailed.

Subjects: DRAPER STATION ANALYSIS TOOL (DSAT), SIMULINK, SIMULATION DESIGN, OBJECT SIMULATION

Kaazempur-Mofrad, M.R.; Vacanti, J.P.; Borenstein, J.T.

A MEMS-Based Renal Replacement System

Solid State Sensors and Actuators. Held in Hilton Head, SC, 06/06/2004 to 06/10/2004. (Draper Report no. P-4198)

Abstract: Over the last decade, medicine and the biological sciences have benefited from advances in microfabrication technologies and microdevices originally developed for consumer and industrial electronics, automotives and aerospace, and national defense. Real-time miniaturized diagnostic tests, implantable drug delivery and minimally invasive imaging technologies are on the verge of revolutionizing the delivery of health care. Beyond these products lies the field of regenerative medicine, a merger of cell biology, computational biology, microfabrication, and biomaterials, aimed at replacing the function of failing tissues and/or organs in patients with end stage organ failure. One of the most critical applications is in the field of renal dialysis, in which waste products in the blood are filtered in an intermittent, invasive and costly manner, with very poor patient outcomes. It is the aim of this work to develop a minimally invasive, continuous hemodialysis capability that utilizes a combination of advances in computational fluid dynamics, Microelectromechanical System (MEMS) fabrication and biomaterials. Here, early ultrafiltration results are reported, using a microfabricated biopolymer blood processing unit, designed, built, and tested in a model system containing a single vascular and dialysate layer.

Subjects: RENAL REPLACEMENT SYSTEM, MICROELECTROMECHANICAL SYSTEM (MEMS), MICROFABRICATION, MICROVASCULAR SYSTEMS, BIOMEDICAL ENGINEERING

Kourepenis, A.; Weinberg, M.

Low-Cost IMU Technology

Unification of Analytical, Computational, and Experimental Solution Methodologies (UACEM) in MEMS and Nanotechnology. Held in Springfield, MA, 10/28/2004 to 10/29/2004. Sponsored by: Society for Experimental Mechanics. (Draper Report no. P-4286)

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), INERTIAL TECHNOLOGY, INERTIAL MEASUREMENT UNIT (IMU)

Kourepenis, A.; Weinberg, M.S.

MEMS Gyroscopes and Accelerometers: A Review of Current Designs and Fabrication Approaches

Plans 2004. Held in Monterey, CA, 04/26/2004 to 04/29/2004. Sponsored by: IEEE. (Draper Report no. P-4178)

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), INERTIAL SENSORS, ACCELEROMETERS

Krebs, M.D.; Tingley, R.D.; Zeskind, J.E.; Kang, J.M.; Holmboe, M.E.; Davis, C.E.

Autoregressive Modeling of Analytical Sensor Data Can Yield Classifiers in the Predictor Coefficient Parameter Space

Bioinformatics, Vol. 1, No. 1, 2004. (Draper Report no. P-4252-REV-A)

Abstract: The analysis of chromatographic data resulting from complex chemical mixtures is challenging. Components may co-elute, causing their signals to overlap. An algorithm that will increase the signal-to-noise ratio so compounds present in low abundance can be better distinguished from noise is useful in this type of analysis. The autoregressive (AR) filter offers the advantage of smoothing chromatograms to increase this ratio, while also offering data compression and increased resolution. Furthermore, this filter can be useful for classification, as the roots of the predictor coefficient vectors represent features present in the data and can therefore be used for pattern recognition. In this paper, we present a novel method for applying AR filtering to chromatogram data. We show that the AR filter outperforms the Savitzky-Golay filter for smoothing noise while retaining important information within chromatograms, and also that AR correlation coefficients have the potential to be used to classify chromatogram data into groups.

Subjects: ANALYTICAL SENSOR, CHROMATOGRAMS, SIGNAL RESOLUTION, AUTOREGRESSIVE FILTERS

Krebs, M.D.; Shnayderman, M.; Kang, J.M.; Holmboe, M.E.; Stair, T.O.; Dorkin, H.L.; Ryan, E.T.; Gelfand, J.A.; Davis, C.E.; Gill, C.J.; Callahan, M.V.

Non-Invasive Breath Analysis Using Field Asymmetric Ion Mobility Spectrometry and Bioinformatics Pattern Recognition

BioDefense & Emerging Infectious Disease Research. Held in Durham, NH, 09/20/2004. Sponsored by: NERCE. (Draper Report no. P-4254)

Subjects: BREATH ANALYSIS, FIELD ASYMMETRIC ION MOBILITY SPECTROMETER (FAIMS), BIOINFORMATICS, VOLATILE ORGANIC COMPOUNDS (VOC)

LeBlanc, J.; Haavisto, J.; Stolfi, M.; Negro, L. Dal; Michel, J.; Duan, X.; Kimerling, L.C.

CMOS-Compatible Erbium Coupled Si Nanocrystal Thin Films For Microphotonics

2004 Materials Research Society Fall Meeting. Held in Boston, MA, 11/29/2004 to 12/03/2004. Sponsored by: MRS. (Draper Report no. P-4271)

Abstract: Er doped Si-rich SiO2 films were deposited through reactive rf magnetron co-sputtering and subjected to a single annealing step to simultaneously form silicon nanocrystals (Si-nc's) and activate the Er emission. Reference Er in stoichiometric SiO2 (Er:SiO2) films were deposited for comparison and the Er emission in the presence of Si-nc's was optimized with respect to the annealing temperature. The Er emission from Er in SiO2, containing Si-nc's (Er:SiO2+Si-nc) films is maximized at annealing temperatures between 600° C and 800° C, where the 1.54-micron emission is enhanced by more than two orders of magnitude relative to Er:SiO2 samples. Efficient energy coupling between Si-nc's and Er ions was demonstrated through excitation cross section measurements and nonresonant Er excitation experiments for samples annealed at temperatures as low as 600° C. Since strong emission can be achieved from Er:SiO2+Si-nc films deposited through a standard CMOS process and annealed at temperatures below 700° C, they can be used to fabricate CMOS-compatible light sources and amplifiers.

Subjects: COMPLEMENTARY METAL OXIDE SEMICONDUCTORS (CMOS), NANOCRYSTALS, MICROPHOTONICS

LeBlanc, J.; Haavisto, J.; Negro, L. Dal; Stolfi, M.; Duan, X.; Kimerling, L.C.; Michel, J.

Optical Gain in Strongly Coupled Erbium-Doped Silicon Nanocrystals Annealed at Low Temperatures

Materials Processing Center, Materials Day 2004, MIT. Held in Cambridge, MA (Draper Report no. P-4282)

Abstract: Erbium and silicon nanocrystal (Si-nc) co-doped SiO2 slab waveguides were fabricated on silicon (Si) substrates by reactive radio-frequency (RF) magnetron sputtering followed by a single thermal annealing step. In the presence of Si-nc, the Er emission is maximized at annealing temperatures between 600°C and 700°C, where the 1.54-µm emission is enhanced by more than two orders of magnitude relative to reference Er in SiO2 samples. For samples annealed at 600°C, pump-dependent variable stripe length (VSL) measurements indicate an optical gain of 4 cm-1 at 1.54 µm. A large coupling coefficient yc = 150 x 10-15 cm3/s between Er ions and Si-nc was found by using a simple coupled rate equation model to describe both the optical emission and the gain data. These Er:Si-nc films can be used for the fabrication of compact waveguide optical amplifiers and integrated light sources with full CMOS compatibility.

Subjects: OPTICAL WAVEGUIDES, NANOCRYSTALS, OPTICAL GAIN

LeBlanc, J.; Haavisto, J.; Stolfi, M.; Michel, J.; Duan, X.; Kimerling, L.C.; Dal Negro, L.; Yi, Y.

Photon Band-Gap Properties and Omnidirectional Reflectance in Si/SiO2 Thue-Morse Quasicrystals

Applied Physics Letters, Vol. 84, No. 25, 06/21/2004, p. 5186-5188. Sponsored by: AIP. (Draper Report no. P-4196)

Abstract: Aperiodic one-dimensional Si/SiO2 Thue-Morse (T-M) multilayer structures have been fabricated in order to investigate both the band gap properties with respect to the system size (band gap scaling) and the omnidirectional reflectance at the fundamental optical band gap. Variable angle reflectance data have demonstrated experimentally a large reflectance band gap in the optical spectrum of a T-M quasicrystal, in agreement with transfer matrix simulations. We explain the physical origin of the T-M omnidirectional band gap as a result of periodic spatial correlations in the complex T-M structure. The unprecedented degree of structural flexibility of T-M systems can provide an attractive alternative to photonic crystals for the fabrication of photonic devices.

Subjects: BAND GAP, PHOTONIC CRYSTALS, PHOTONIC DEVICES, REFLECTANCE

McConley, M.; Dever, C.; Mettler, B.; Feron, E.; Popovic, J.

Trajectory Interpolation for Parametrized Maneuvering and Flexible Motion Planning of Autonomous Vehicles

Guidance, Navigation, and Control Conference and Exhibit. Held in Providence, RI, 08/16/2004 to 08/19/2004. Sponsored by: AIAA. (Draper Report no. P-4206)

Abstract: This paper describes a method of generating continuously parametrized maneuver classes based on a finite number of user-provided examples motions. A trajectory interpolation algorithm performs a smooth transformation of vehicle maneuvers across a continuous range of boundary conditions while enforcing nonlinear system equations of motion as well as nonlinear equality and inequality constraints. The scheme is particularly useful for describing motions that deviate widely from the range of linearized dynamics and where satisfactory examples may be found from off-line nonlinear programming solutions or human pilot motion capture. The interpolation algorithm is computationally efficient, making it a suitable alternative for near-real-time maneuver synthesis, particularly when used in concert with a vehicle motion planner. Experimental application to a 3-degree-of-freedom rotorcraft test bed demonstrates the essential features of system and trajectory modeling, maneuver example selection, maneuver class synthesis, and integration into a hybrid system path planner.

Subjects: AUTONOMOUS VEHICLES, INTERPOLATION, MOTION PLANNING, ROTORCRAFT AIRCRAFT

Manobianco, J.; Bickford, J.; George, S.; Pister, K.S.J.; Manobianco, D.M.

GEMS: A Revolutionary Concept for Planetary and Space Exploration

Institute for Space and Nuclear Power Studies, Space Technology and Applications International Forum. Held in Albuquerque, NM, 02/08/2004 to 02/12/2004. Sponsored by: ISNPS. (Draper Report no. P-4167)

Abstract: A novel observing system known as Global Environmental MEMS Sensors (GEMS) offers the potential to significantly improve the ability to take in situ measurements for a variety of space missions. The GEMS concept features devices with completely integrated sensing, power, and communications with characteristic dimensions of just millimeters. Thousands of these low-cost devices could potentially be deployed together from a spacecraft to enable distributed sensing in planetary and other space environments. The deployment of such probes is analyzed and discussed for various scenarios on Mars that would provide measurements with unprecedented spatial and temporal resolution. The extended coverage provided by the arrays would improve the ability to calibrate remote sensing data while also extending the areas traditionally measured by localized landers. The unique features of such a system could significantly improve the capabilities for planetary and space exploration in the near and far term.

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), MARS PROBES, ARTIFICIAL INTELLIGENCE, REMOTE SENSING, SPACE EXPLORATIONS, MEASUREMENTS

Negro, L. Dal; Yi, Y.; Michel, J.; Duan, X.; Kimerling, L.C.; LeBlanc, J.; Haavisto, J.; Stolfi, M.

Omnidirectional Reflectance and Optical Gap Properties of Si/SiO2 Thue-Morse Quasicrystals

Material Research Society, 2004 Spring Meeting. Held in San Francisco, CA, 04/12/2004 to 04/16/2004. Sponsored by: MRS. (Draper Report no. P-4181)

Abstract: Aperiodic one-dimensional Si/SiO2 Thue-Morse (T-M) multilayer structures have been fabricated, for the first time, in order to investigate both the band-gap behavior, with respect to the system size (band-gap scaling), and the omnidirectional reflectance of the fundamental optical band-gap. Variable angle reflectance data have experimentally demonstrated a large reflectance band-gap in the optical spectrum of a T-M quasicrystal, in agreement with transfer matrix simulations. We have explained the physical origin of the T-M omnidirectional band-gap as a result of periodic spatial correlations in the self-similar T-M structure, as revealed by Fourier transform and wavelet analysis. The unprecedented degree of structural flexibility shown by T-M systems can provide an attractive alternative to photonic crystals for the fabrication of photonic devices.

Subjects: BAND GAP, QUASICRYSTALS, PHOTONIC DEVICES

Pettit, R.L.; Homer, M.L.

An Autonomous Threat Evasion Response Algorithm for Unmanned Air Vehicles During Low Altitude Flight

Intelligent Systems Technical Conference. Held in Chicago, IL, 09/20/2004 to 09/22/2004. Sponsored by: AIAA. (Draper Report no. P-4219)

Abstract: As military unmanned air vehicles increasingly enter the low-altitude regime of the battlefield, such platforms need to be both threat and terrain aware. Lack of a communications link or timely response by the operator motivates the need for an autonomous threat evasion capability. This paper first explores the scenario of a vehicle encountering a previously unknown threat. The discussion leads to the proposal of a genetic algorithm approach for autonomous response. The algorithm develops a trajectory (three spatial dimensions and time) while respecting the vehicle's dynamic maneuver capabilities. We detail the algorithm's logic and implementation, including how feasibility is maintained during crossover and mutation operations. Results from a case study involving an unmanned autonomous attack helicopter encountering a ground threat yield a performance assessment.

Subjects: UNMANNED AERIAL VEHICLES (UAV), THREAT EVASION, ALGORITHMS, CASE STUDIES

Phillips, R.; Kachmar, P.

Apollo Rendezvous Navigation

Guidance and Control Conference. 27th. Held in Breckenridge, CO, 02/04/2004 to 02/08/2004. Sponsored by: AAS. (Draper Report no. P-4207)

Abstract: The Apollo guidance, control, and navigation system was designed by Draper Laboratory (nee the MIT Instrumentation Laboratory) during the mid to late 1960s, but was the legacy of a series of earlier studies of Mars photographic reconnaissance missions that had been sponsored by the Air Force Ballistic Missile Division. The development of rocket engines and inertial measurement instruments was basic to turning the dream of poets into the reality of a trip to the moon, but on a narrower scale, the development of practical guidance and navigation algorithms was enabled by the development of programmable digital computers and of higher order programming languages. In this paper, we will focus in particular on navigation and guidance associated with the rendezvous of the Lunar Module with the Command Module as they orbited the moon. The rendezvous was accomplished with a sequence of thrusting maneuvers interspersed with relative measurements between the two vehicles. The Lunar Module had the primary responsibility for these measurements and maneuvers, but the Command Module had similar capabilities that could be used in a backup mode. The Lunar Module was equipped with a radar that supplied range, range rate, and two angle measurements. The Command Module was initially to be equipped with only a sextant through which the Command Module pilot could sight the Lunar Module. These angular measurements were, in the end, augmented with a range measurement based on the communications link between the two vehicles. The rendezvous sequence began with each vehicle observing the other using their respective set of sensors. After a short sequence of measurements, the first of six maneuvers was performed. These maneuvers set up the Lunar Module in a coelliptic orbit below and behind the Command Module. After another sequence of sensor measurements, an intercept maneuver was performed. This was succeeded by interspersed measurements and two mid-course correction maneuvers and finally terminated by a braking maneuver. At the end of this sequence, the vehicles were in close proximity and the pilots manually maneuvered them to docking.

Subjects: APOLLO NAVIGATION SYSTEM, RENDEZVOUS NAVIGATION, COMMAND MODULES

Ross, M.; D'Souza, C.N.

Hybrid Optimal Control Framework for Mission Planning

Guidance, Navigation, and Control Conference and Exhibit. Held in Providence, RI, 08/16/2004 to 08/19/2004. Sponsored by: AIAA. p. 1-9. (Draper Report no. P-4280)

Abstract: With the progressive sophistication of future missions, it has become increasingly apparent that a new framework is necessary for efficient planning, analysis, and optimization of various concepts of operation ( CONOPS). In recognizing that CONOPS involve categorical variables, we propose a hybrid optimal control framework that mathematically formalizes such problems. Hybrid optimal control theory extends ordinary optimal control theory by including categorical variables in the problem formulation. The proposed formalism frees mission planners to focus on high-level decision-making by automating and optimizing the details of the inner loops. The eventual goal of this formalism is to develop efficient tools and techniques to support the objective of increasing autonomy for future systems. In using the pseudospectral knotting method to solve hybrid optimal control problems, we generate a mixed-variable programming (MVP) problem. A simple, feasible integer programming subproblem is identified that reduces the combinatorial complexity of solving the MVP. In addition to developing the framework using various examples from aerospace engineering, we provide details for a two-agent benchmark problem associated with a multiagent launch system. The entire process is illustrated with a numerical example.

Subjects: MOBILE ROBOTS, HYBRID SYSTEMS, MULTI-AGENT SYSTEMS, TRAJECTORY OPTIMIZATION

Ross, I.M.; D'Souza, C.N.

Rapid Trajectory Optimization of Multi-Agent Hybrid Systems

Guidance, Navigation, and Control Conference. Held in Providence, RI, 08/01/2004. Sponsored by: AIAA. (Draper Report no. P-4202)

Abstract: Multi-agent systems in aerospace applications correspond to coordinated control of multiple vehicles such as those arising in multiple entry-vehicle systems, air-traffic control, and formation flying to name a few examples. In certain applications, the vehicles may be docked or separated in mid-flight, resulting in switches in the dimension of the continuous-time state and control variables. Dimensional switching distinguishes such problems in a somewhat unique way when compared with other multi-agent systems such as mobile robots where docking may not be allowed. A hybrid optimal control framework is presented that mathematically formalizes such mission planning problems toward the goal of quick flight plan analyses via rapid trajectory optimization. One motivation for this formalism is that many future systems are conceived as multi-agent control systems, and it has become increasingly apparent that a new framework is necessary to efficiently analyze various scenarios. The pseudospectral knotting method is proposed as a fast computational technique to solve such hybrid optimal control problems. The concepts are illustrated for a two-agent benchmark problem associated with a multi-agent launch system where the return vehicle is constrained by a return point requirement.

Subjects: TRAJECTORY OPTIMIZATION, HYBRID CONTROL, HYBRID SYSTEMS

Sauter, L.M.; Proulx, R.R.; Musoff, H.

Satellite Constellation Design for a Mid-Course Ballistic Missile Intercept

Space Flight Mechanics Conference. 14th. Held in Maui, HI, 02/08/2004 to 02/12/2004. Sponsored by: AAS/AIAA. (Draper Report no. P-4163)

Abstract: This paper will establish a conceptual approach to the design of satellite-based mid-course missile defense. This intercept problem leads to a new paradigm of coverage for constellation design where interceptor "reachability" replaces visual coverage. Interceptors in this concept are limited in their time of flight and deltaV capabilities. Missile defense in this research will focus on a specific simulated threat, e. g., North Korea. Previous constellation designs, based on ground coverage by symmetrical patterns of circular orbits, provide an initial basis for the new reachability metric. Although nonsymmetric and noncircular constellations are considered, this paper explores constellations derived from Walker delta patterns. They provide an upper bound on the number of satellites required. These a priori constellations are optimized to achieve 100% interceptor coverage. Results will show that satellite-based mid-course ballistic missile defense from a regional threat is achievable with as few as 21 satellites.

Subjects: SATELLITE CONSTELLATION, BALLISTIC MISSILE DEFENSE (BMD), SATELLITE INTERCEPTION SYSTEMS

Stolfi, M.; Duan, X.; Michel, J.; Kimerling, L.C.; LeBlanc, J.; Haavisto, J.; Dal Negro, L.

Light Emission from Silicon Nanocrystals (Si-nc's) in SiOx Films Prepared by RF Magnetron Sputtering

American Vacuum Society. Held in Burlington, MA, 06/14/2004 to 06/15/2004. Sponsored by: NEAVS. (Draper Report no. P-4231)

Subjects: LIGHT EMISSION, SILICON, SPUTTERING

Weinberg, E.J.; Borenstein, J.T.; Kaazempur-Mofrad, M.R.; Orrick, B.; Vacanti, J.P.

Design and Fabrication of a Constant Shear Microfluidic Network for Tissue Engineering

Spring Conference. Held in San Francisco, CA, 04/15/2004. Sponsored by: MRS. (Draper Report no. P-4180)

Abstract: Recent progress in microfabrication of biodegradable materials has resulted in the development of a three-dimensional construct suitable for use as a scaffold for engineering blood vessel networks. These networks are designed to replicate the critical fluid dynamic properties of physiological systems such as the microcirculation within a vital organ. Ultimately, these 3D microvascular constructs will serve as a framework for population with organ-specific cells for applications in organ assist and organ replacement. This approach for tissue engineering utilizes highly engineered designs and microfabrication technology to assemble cells in three-dimensional constructs that have physiological values for properties such as mechanical strength, oxygen, nutrient and waste transport, and fluidic parameters such as flow volume and pressure. Three-dimensional networks with appropriate values for blood flow velocity, pressure drop and hematocrit distribution have been designed and fabricated using replica molding techniques, and populated with endothelial cells for long-term microfluidic cell culture. One critical aspect of the fluid dynamics of these systems is the shear stress exerted by blood flow at the walls of the vessel; a key parameter because of well-known mechanotransduction phenomena from mechanical shear forces that govern endothelial cell behavior. In this work, we report the design and construction of three-dimensional microfluidic constructs for tissue engineering that have uniform wall shear stress throughout the network. This type of control over the shear stress offers several advantages over earlier approaches, including more uniform seeding, more rapid achievement of confluent coatings, and better control over endothelial cell behavior for in vitro and in vivo studies.

Subjects: MICROFLUIDICS, TISSUE ENGINEERING, MICROVASCULAR SYSTEMS

Weinberg, M.; Kwok, P.; Breuer, K.

Fluid Effects in Vibrating Micromachined Structures

Unification of Analytical, Computational, and Experimental Solution Methodologies (UACEM) in MEMS and Nanotechnology. Held in Springfield, MA, 10/28/2004 to 10/29/2004. Sponsored by: Society for Experimental Mechanics. (Draper Report no. P-4285)

Subjects: MICROELECTROMECHANICAL SYSTEM (MEMS), HYDRODYNAMIC LIFT, HYDRODYNAMIC DAMPING, MICROMACHINED, FLUID

Yang, L.; Kreamer, W.; Adams, M.; Carr, F.; Guerra, C.J.; Page, L.; McConley, M.

Hierarchical Planning for Large Numbers of Unmanned Vehicles

1st Intelligent Systems Technical Conference. Held in Chicago, IL, 09/20/2004 to 09/23/2004. Sponsored by: AIAA. (Draper Report no. P-4268)

Abstract: In this paper, we describe an approach for planning missions for teams of unmanned vehicles in large theater campaigns. The method uses a hierarchical structure that decomposes a complex optimization problem into smaller, more manageable subproblems. Each level of the hierarchy solves a simpler optimization problem and produces objectives and constraints for the next lower level to solve. In the algorithm, we use three levels: 1) Team Composition and Task Allocation (TCTA), 2) Team Dynamics and Tactics (TDT), and 3) Cooperative Task and Path Planning (CTPP). We describe the optimization algorithms used at each level and address issues that arise from the decomposition. Results from a representative battle simulation are shown and used for discussion.

Subjects: UNMANNED AERIAL VEHICLES (UAV), TEAM COMPOSITION AND TASK ALLOCATION (TCTA), TEAM DYNAMICS AND TACTICS (TDT), COOPERATIVE TASK AND PATH PLANNING (CTPP), ALGORITHMS, HIERARCHIAL PLANNING