Draper Laboratory Research Articles

Digital Control and Readout of MEMS Gyroscope Using Second-Order Sliding Mode Control

Microelectromechanical system (MEMS) is a kind of MEMS that has been utilized to monitor the angular speed of moving objects on several occasions and has attracted the interest of several organizations across the globe. This type of sensor has the benefits of excellent integration, cheap cost, and low power utilization. This study begins by describing the research and development of silicon MEMS gyroscopes since the 1980s, including the work of several universities, such as Draper Laboratory and UC Berkeley, as well as various design ideas, control systems, and architectures. Matching resonance frequencies of the driving and sense mechanical resonators may significantly improve the efficiency of MEMS gyroscopes. In a closed-loop readout circuit, however, exact control of the resonance frequency is difficult. Because of their inexpensive production costs in large numbers, MEMS gyroscopes are gaining appeal. Because of substantial nonstationary noise processes in the output of MEMS gyros, such as 1/ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${f}$ </tex-math></inline-formula> noise, this creates difficulty for navigation system designing. In the implementation, relative error in ramp and step function is determined through the proposed methodology. Furthermore, the second-order sliding mode control (SoSMC) is used in the sliding mode of the gyroscope to minimize the chattering effect.

Hot Spot of Invention: Charles Stark Draper, Mit, and the Development of Inertial Guidance and Navigation

The idea that a vehicle could navigate entirely on its own, with no references to outside signals, formed a compelling narrative for Cold War engineers and led to the technology of “inertial guidance.” Few were as influential at creating that narrative and technology than Massachusetts Institute of Technology (Mit) professor Charles Stark Draper. Draper also built an institution, known as the Mit Instrumentation Laboratory, which survives today as the Charles Stark Draper Laboratories in Cambridge, Massachusetts, having contentiously spun off from Mit in the 1970s. Thomas Wildenberg's new history of Draper and his laboratory, Hot Spot of Invention, chronicles the man and his laboratory. Draper, trained in psychology and physics, got his start engineering instruments for internal combustion engines, which he then applied to aircraft engines. After initial success, in the 1930s he developed gyroscopically controlled instruments to aid pilots flying blind through clouds and weather—laying crucial...

A Language for Programmable Hardware Security

No paper or presentation is available, but information on the "inherently secure processor" developed by Draper Laboratory can be found here: https://www.draper.com/explore-solutions/inherently-secure-processor

Fabrication and Preparation of Micro-Coaxial Wires: Electrodeposition of Conductive Shields

We describe the fabrication of micro-coaxial cables with diameters of 25 to 300 micrometers. Draper Laboratory is developing a new microelectronics packaging platform that relies on such microcoax, in place of copper interconnects, for both power and signal distribution among the packaged electronic components. This platform could save design time and fabrication labor over conventional packaging techniques for custom electronics with small production volumes and offers a way to rapid prototype and/or edit circuits. In this work, we focus on the fabrication of microcoax for power distribution. The fabrication process of the metal-dielectric-metal cross-section of the microcoax begins with a commercial metal wire of 18 to 150 micrometer diameter, which is either purchased with a polymer insulation of 1 to 12 micrometer thickness, or is insulated with SiO2 or Al2O3 of 0.1 to 2 micrometer thickness by PECVD or ALD processes. Next, a thin Ti/Au bilayer is applied to the insulated wire by electron beam evaporation and acts both as an adhesive layer and as electrical contact to plate the outer metal shield to its full desired thickness. The metal shield is electroplated using a cyanide-free gold sulfite chemistry that produces a soft satin to bright electrodeposit, meeting Type IIIA of Mil-G-45204 C requirements (i.e., ≥ 99.9 % gold purity and Knoop hardness 90 maximum). Straight DC, temperature of 60 °C, current density of 2 mA/cm2and mild agitation were chosen as parameters for Au electroplating conditions. Gold electrodeposits exhibit very low roughness, good corrosion resistance, excellent solderability, high shine and with evaporated seed metal, good adhesion to the polymer dielectrics. The shield thickness is chosen to give a resistance equal to or less than the resistance of the metal core, e.g., 34 micrometers of plated Au for a 127 micrometer diameter Cu core. The use of the microcoax for packaging requires lengths of microcoax of < 15 mm with the wire tips prepared for electrical connection, i.e., tips where the metal shield ends abruptly leaving the center metal wire exposed for bonding, and so we introduce at periodic intervals along the wire length regions where the outer layers are more easily stripped to expose the metal core. We have accomplished this either by ad hoc placement of a plating-resistant (nail polish or soft-baked photoresist) bead on the seed metal to pattern regions where no shield metal is electrodeposited; or by an evaporation mask during seed metal deposition to pattern regions where neither the metal seed nor the metal shield are deposited. The core metal is then exposed in the beaded or masked regions by wet etching the seed metal, if necessary, and UV laser ablation of the polymer dielectric. In addition to the fabrication processes, we will also discuss the fixturing and handling protocols required for these fine diameter wires. Fixturing is designed to accomplish four criteria: to minimize handling among the various process steps (insulating the wire, e-beam evaporation, electroplating); to pattern the microcoax lengths and abrupt edges to the electrodeposited metal; to make electrical contact to the seed metal during electroplating; and for the necessary volume and yield. We will describe our scale-up from an initial proof-of-concept process that produced 0.1 meters of microcoax of arbitrary segment lengths to a simpler process that produces 2 meters of microcoax of well-defined segment length.

Verifying cyber attack properties

Abstract The heterogeneous, evolving and distributed nature of Cyber-Physical Systems (CPS) means that there is little chance of performing a top down development or anticipating all critical requirements such devices will need to satisfy individually and collectively. This paper describes an approach to verifying system requirements, when they become known, by performing an automated refinement check of its composed components abstracted from the actual implementation. This work was sponsored by the Charles Stark Draper Laboratories under the DARPA HACMS project. The views, opinions, and/or findings expressed are those of the authors and should not be interpreted as representing the official views or policies of the Department of Defense or the U.S. Government

Development, integration, and test architecture for a software-based hardware-agnostic fault tolerant flight computer

In this article, we describe the development, integration and test architecture of a Fault Tolerant Flight Computer System (FTCS) designed by the Charles Stark Draper Laboratory (CSDL) for a manned spacecraft and elaborate on how this architecture might be improved upon and used generically among similar fault-tolerant systems. As the sophistication and complexity of software-defined fault tolerance systems continue to grow, leveraging commercial hardware and flexible architectures to support and verify the performance of fault-tolerant systems becomes critical. It is hoped that the methods described in this article provide a foundation for future programs to save on costs and resources, as well as develop and validate future systems with the highest possible level of functionality and reliability.

CFD Modeling and Modification of Cleanroom Design to Achieve ISO Class 6 Performance

The Charles Stark Draper Laboratory Microfabrication Lab, located in Cambridge, Massachusetts, was commissioned in November 2012. The design and construction of this lab was discussed in a previous paper.[1] The laboratory comprises an area of 700.1 m2 (7545 ft2) under filter with 280 m2 (3014 ft2) of clean chase space, divided into 11 distinct cleanrooms. This paper focuses on the design and operation of one ISO Class 6 [2] cleanroom (3335) used for wet processing of microelectromechanical systems (MEMS) and multichip modules (MCM). The initial design criteria are discussed, along with installation of the tools and the non-compliance of ISO Class 6 particle counts. Based on these results, computational fluid dynamics (CFD) modeling software was employed to study the airflow in the room and modify the airflow to be compliant with ISO Class 6 standards.

A Conversation with Nan Laird

Nan McKenzie Laird is the Harvey V. Fineberg Professor of Biostatistics at the Harvard T. H. Chan School of Public Health. She has made fundamental contributions to statistical methods for longitudinal data analysis, missing data and meta-analysis. In addition, she is widely known for her work in statistical genetics and in statistical methods for psychiatric epidemiology. Her 1977 paper with Dempster and Rubin on the EM algorithm is among the top 100 most highly cited papers in science [Nature 524 (2014) 550-553]. Her applied work on medical practice errors is widely cited among the medical malpractice community. Nan was born in Gainesville, Florida, in 1943. Shortly thereafter, her parents Angus McKenzie Laird and Myra Adelia Doyle, moved to Tallahassee, Florida, with Nan and her sister Victoria Mell. Nan started college at Rice University in 1961, but then transferred to the University of Georgia where she received a B.S. in Statistics in 1969 and was elected to Phi Beta Kappa. After graduation Nan worked at the Massachusetts Institute of Technology Draper Laboratories where she worked on Kalman filtering for the Apollo Man to the Moon Program. She enrolled in the Statistics Department at Harvard University in 1971 and received her Ph.D. in 1975. She joined the faculty of Harvard School of Public Health upon receiving her Ph.D., and remains there as research professor, after her retirement in 2015. The interview was conducted in Boston, Massachusetts, in July 2014. A link to Nan's full CV can be found at \surlwww.hsph.harvard.edu/nan-laird/.

Research development of silicon MEMS gyroscopes: a review

Micro-electromechenical Systems (MEMS) gyroscope is widely used in many occasions to measure the angular speed of the moving objects and attracts the attentions of many research institutions all over the world. This kind of sensor possesses the advantages of high degree of integration, low cost and consumption of power. This paper first introduces the research development of silicon MEMS gyroscope since eighties of last century; the researches of many institutions such as Draper Laboratory and UC Berkeley are mentioned and different design principles, control methods and structures are presented. This review then presents the key theories and technologies of the sensor and some research results of them. In additional, some recent new applications of MEMS gyroscope are also been introduced in this paper such as wearable motion capture system and micro inertial measurement unit. Finally, according to the review, some views of silicon MEMS gyroscope and its future prospects are put forwarded.

An Overview of the LADEE Ultraviolet-Visible Spectrometer

The Ultraviolet-Visible Spectrometer (UVS) instrument, which flew on the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft (SC), was one of three science instruments used to characterize the lunar exosphere. UVS is a point spectrograph operating between 230–810 nm and used its two optical apertures to make observations of the exosphere just above the surface at a range of local times and altitudes, as well as making solar occultation measurements at the lunar sunrise terminator. The instrument was led out of NASA Ames Research Center with primary hardware being provided by Draper Laboratories. Final instrument integration, testing and operations were performed at NASA Ames. Over the course of the 140-day LADEE mission UVS acquired more than 1 million spectra, providing a unique data set for lunar exosphere gasses and dust.

COMBS: A Biosurveillance Ecosystem (BSVE) Prototype

The goal of DTRA's Biosurveillance Ecosystem (BSVE) program is to significantly reduce the time required to identify threats to human health, whether of malicious or natural origin, and respond appropriately. Draper Laboratory is leading a team to develop the Collaborative Overarching Multi-feed Biosurveillance System (COMBS) for BSVE to revolutionize biosurveillance capabilities. USG analysts whose jobs are to reduce risks to national security will benefit from rapid and thorough information access, as will local public health authorities and individual citizens. This poster will provide an overview of the COMBS project and current progress towards meeting the goals of the BSVE.

Abstract P5-04-08: Modeling breast cancer dormancy

Abstract Most cancer mortality results from distant metastases. The metastatic microenvironment protects ectopic tumors, these nodules are often resistant to agents that eradicate the primary mass. Although significant interventional progress has been made on primary tumors, the lack of relevant accessible model in vitro systems in which to study metastases has plagued metastatic therapeutic development – particularly among micrometastases. One third of women diagnosed with breast cancer (BC) will have metastatic disease which often presents years after a seeming cure from the primary malignancy. An in silico model of micrometastases strongly suggests that these disseminated cells are quiescent, or ‘dormant’, for long periods of time. Current models fail to recapitulate metastatic dormancy, in vivo due to issues of spontaneous metastases and rodent lifespan and in vitro due to the nascent state of organotypic organs or microphysiological systems (MPS). We hypothesize that even the most developed MPS do not allow tumors to attain dormancy due to continued stress signaling from stiff matrices and an artificial microenvironment. We use an innovative all human three dimensional liver MPS to faithfully reproduce human physiology and pathology. In the initial iteration, the liver cells are isolated from therapeutic partial hepatectomies, but as this source may be limiting, we are examining induced pluripotent stem cells (iPSC). Currently these iPSC-derived hepatocyte-like cells demonstrate cyp p450 activity and production of fibrinogen and urea through 15 days in our MPS, albeit at levels below fresh human hepatocytes; optimization protocols are underway. In the first phase of this work we optimized the flow rate and seeding of hepatocytes with non-parenchymal cells (NPCs) from fresh human liver resections. We found that higher flow rates produced poorer tissue formation and increased stress fibers/actin filaments. We maintained functioning hepatocytes in the MPS through 15 days. Hepatocyte function and injury was measured by urea, lactate, AST, ALT, A1AT, fibrinogen and cyp p450 assays. NPCs survived through the 15 day endpoint with immunofluorescent microscopy visualizing leukocytes, endothelial cells and macrophages. The proliferative MDA MB 231 BC cell line showed preliminary evidence of growth attenuation after 12 days of culture in a subpopulation of cells in our MPS. Luminex cancer panel studies are underway with systems biology modeling to describe a communication network in the early microenvironment of micrometastases. In parallel we are piloting hydrogel scaffolds that support tissue formation but provide a more physiologic rheology; stiff supporting materials yield an inflammatory phenotype in the NPC which forces even well-differentiated BC cells towards a mesenchymal phenotype. We found that hydrogels support hepatocytes through 15 days and incorporate cancer cells. Micropumps are also being developed by Draper Laboratories to allow for physiologic diurnal variations of hormones and nutrients to liver tissues to accurately assess dormancy and chemotherapy response. The completion of these studies will provide insights into the tumor biology of dormant micrometastases and an accessible tool for testing of therapeutics against metastatic BC in a metabolically competent system. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-04-08.

Case Study: Design and Construction of the Draper Laboratory Microfabrication Center

For 25 years, Draper Laboratory has been active in the areas of microelectromechanical systems (MEMS) and multichip modules (MCM), using two separate laboratories. When these laboratories were constructed, cleanroom technology was in its mid-life cycle. To meet evolving R&amp;D needs, the cleanroom facilities recently underwent a major renovation as described in this article.

TALARIS project update: Overview of flight testing and development of a prototype planetary surface exploration hopper

The TALARIS (Terrestrial Artificial Lunar And Reduced GravIty Simulator) project is intended to test GNC (Guidance, Navigation, and Control) algorithms on a prototype planetary surface exploration hopper in a dynamic environment with simulated reduced gravity. The vehicle is being developed by the Charles Stark Draper Laboratory and Massachusetts Institute of Technology in support of efforts in the Google Lunar X-Prize contest. This paper presents progress achieved since September 2010 in vehicle development and flight testing.Upgrades to the vehicle are described, including a redesign of the power train for the gravity-offset propulsion system and a redesign of key elements of the spacecraft emulator propulsion system. The integration of flight algorithms into modular flight software is also discussed.Results are reported for restricted degree of freedom (DOF) tests used to tune GNC algorithms on the path to a full 6-DOF hover-hop flight profile. These tests include 3-DOF tests on flat surfaces restricted to horizontal motion, and 2-DOF vertical tests restricted to vertical motion and 1-DOF attitude control. The results of tests leading up to full flight operations are described, as are lessons learned and future test plans.

About the Authors

About the Authors

A 10 Point Checklist for Getting it Off the Shelf

Far too many R&amp;D programs in industry as well as government result in reports or prototypes that represent fundamentally good ideas but end up gathering dust on a shelf. Ellison "Dick" Urban, formerly of DARPA (Defense Advanced Research Projects Agency) and now the Director of Washington Operations at Draper Laboratory, has had considerable experience with technology transition. We talked to him about his guidelines for success.

Anisotropic Collagen Fibrillogenesis Within Microfabricated Scaffolds: Implications For Biomimetic Tissue Engineering

Anisotropic collagen fibrillogenesis is demonstrated within the pores of an accordion-like honeycomb poly(glycerol sebacate) tissue engineering scaffold. Confocal reflectance microscopy and image analysis demonstrate increased fibril distribution order, fibril density, and alignment in accordion-like honeycomb pores compared with collagen gelled unconstrained. Finite element modeling predicts how collagen gel and scaffold mechanics couple in matching native heart muscle stiffness and anisotropy.

Bad vibes

The U.S. Department of Homeland Security (DHS), which operates airport security checkpoints in the United States, is spending upward of US $7 million a year trying to develop technology that can detect the evil intent of the terrorists among us. Yes, you read that correctly: It is intended to read the minds of suspicious peoples. Dozens of researchers across the country are in the middle of a five-year program contracted primarily to the Charles Stark Draper Laboratory, in Cambridge, Mass. They've developed a psychophysiological theory of "malintent"-basically, a hodgepodge of behaviorism and biometrics according to which physiological changes can give away a terrorist's intention to do immediate harm. So far, they've spent $20 million on biometric research, sensors, and a series of tests and demonstrations.

Autonomous safety and reliability features of the K-1 avionics system

Kistler Aerospace Corporation is developing the K-1, a fully reusable, two-stage-to-orbit launch vehicle. Both stages return to the launch site using parachutes and airbags. Initial flight operations will occur from Woomera, Australia. K-1 guidance is performed autonomously. Each stage of the K-1 employs a triplex, fault tolerant avionics architecture, including three fault tolerant computers and three radiation hardened Embedded GPS/INS units with a hardware voter. The K-1 has an Integrated Vehicle Health Management (IVHM) system on each stage residing in the three vehicle computers based on similar systems in commercial aircraft. During first-stage ascent, the IVHM system performs an Instantaneous Impact Prediction (IIP) calculation 25 times per second, initiating an abort in the event the vehicle is outside a predetermined safety corridor for at least 3 consecutive calculations. In this event, commands are issued to terminate thrust, separate the stages, dump all propellant in the first-stage, and initiate a normal landing sequence. The second-stage flight computer calculates its ability to reach orbit along its state vector, initiating an abort sequence similar to the first stage if it cannot. On a nominal mission, following separation, the second-stage also performs calculations to assure its impact point is within a safety corridor. The K-1's guidance and control design is being tested through simulation with hardware-in-the-loop at Draper Laboratory. Kistler's verification strategy assures reliable and safe operation of the K-1.

Squashing a Matrix by Adding an Imaginary Part: 10776

Solution by David W. Carter, Draper Laboratory, Cambridge, MA. The minimum rank of the combination is Fr/21, where r = rank A. It is convenient to work in a more general setting. Let K be a field, A an m-by-n matrix over K, and ae a nonzero element of an algebraic extension of K. Define p(K, A, ao) = minB rank (A + aoB), where B ranges over m-by-n matrices with entries in K. If S is an invertible matrix of order m over K, then p(K, SA, a) = p(K, A, a). Similarly, p(K, AT, o!) = p(K, A, a!) when T is an invertible matrix of order n. By elementary linear algebra, there exist invertible matrices S and T such that SAT = E, where E = (Ir 0). Hence it suffices to determine p(K, E, a). Let B* be an m-by-n matrix such that E + aB* achieves the minimum rank. We may assume that the last m -r rows of B* are zero, since the dimension of the vector space over L spanned by the first r rows of E + aB* is not more than the dimension of the space spanned by all m rows. Similarly, we may assume that the rightmost n -r columns of B* are zero. Thus B* has the form (C O), where C is an r-by-r matrix over K. The rank of E + aoB* is the rank of 1r + oaC. This is less than r if and only if -a71l is an eigenvalue of C. Indeed, the rank of Ir + aoC equals r s, where s is the dimension of the eigenspace associated with eigenvalue -o-1 of C. Let f be an irreducible polynomial over K with -a-1 as a root. The degree d of f is the degree of the field extension [K(a): K]. If C has s linearly independent eigenvectors with eigenvalue -a-1, then fS divides the characteristic polynomial of C. Thus ds < r. Conversely, if s is a positive integer such that ds < r, then we construct an rby-r block diagonal matrix over K with s linearly independent eigenvectors having eigenvalue -o-1: use s blocks equal to the d-by-d companion matrix for f and one remaining block Ir-ds* We have shown that p(K,A,a) = Fr/dl. When K = IR and oa = i, we have d = 2.