High-speed civil transport flight- and propulsion-control technological issues

Technology advances required in the flight and propulsion control system disciplines to develop a high speed civil transport (HSCT) are identified. The mission and requirements of the transport and major flight and propulsion control technology issues are discussed. Each issue is ranked and, for each issue, a plan for technology readiness is given. Certain features are unique and dominate control system design. These features include the high temperature environment, large flexible aircraft, control-configured empennage, minimizing control margins, and high availability and excellent maintainability. The failure to resolve most high-priority issues can prevent the transport from achieving its goals. The flow-time for hardware may require stimulus, since market forces may be insufficient to ensure timely production. Flight and propulsion control technology will contribute to takeoff gross weight reduction. Similar technology advances are necessary also to ensure flight safety for the transport. The certification basis of the HSCT must be negotiated between airplane manufacturers and government regulators. Efficient, quality design of the transport will require an integrated set of design tools that support the entire engineering design team

Space Shuttle GN and C Development History and Evolution

Completion of the final Space Shuttle flight marks the end of a significant era in Human Spaceflight. Developed in the 1970 s, first launched in 1981, the Space Shuttle embodies many significant engineering achievements. One of these is the development and operation of the first extensive fly-by-wire human space transportation Guidance, Navigation and Control (GN&C) System. Development of the Space Shuttle GN&C represented first time inclusions of modern techniques for electronics, software, algorithms, systems and management in a complex system. Numerous technical design trades and lessons learned continue to drive current vehicle development. For example, the Space Shuttle GN&C system incorporated redundant systems, complex algorithms and flight software rigorously verified through integrated vehicle simulations and avionics integration testing techniques. Over the past thirty years, the Shuttle GN&C continued to go through a series of upgrades to improve safety, performance and to enable the complex flight operations required for assembly of the international space station. Upgrades to the GN&C ranged from the addition of nose wheel steering to modifications that extend capabilities to control of the large flexible configurations while being docked to the Space Station. This paper provides a history of the development and evolution of the Space Shuttle GN&C system. Emphasis is placed on key architecture decisions, design trades and the lessons learned for future complex space transportation system developments. Finally, some of the interesting flight operations experience is provided to inform future developers of flight experiences

Optical Rotary Sensors for Avionic Applications

RÉSUMÉ Cette thèse concerne des nouveaux capteurs optiques dédiés aux systèmes de contrôle de vol d’avions «fly-by-wire (FBW)». Les capteurs de déplacement sont utilisés dans les systèmes de contrôle de vol pour détecter la distraction du pilote, les déplacements de l'actionneur et ceux de la surface de vol. Actuellement, les capteurs « Rotary variable displacement transducers - RVDTs» utilisés dans les systèmes de contrôle de vol d'avions FBW sont les capteurs basés sur des circuits magnétiques et électroniques analogiques. Donc, une interface électronique est nécessaire pour la démodulation et numérisation des signaux reçus. Par conséquent, des paires de fils longs torsadés sont utilisés pour connecter le RVDT à l’ordinateur installé à bord de l’avion. Les paires de fils torsadés sont lourds et sensibles aux interférences électromagnétiques (IEM) et aux coups de foudre qui peuvent se produire pendant le vol. Nous proposons des capteurs optiques intelligents pour réduire le poids de l’avion, la consommation du carburant pour un environnement vert, l’IEM et pour utiliser moins de pièces métalliques afin de protéger davantage l’avion contre les coups de foudre. La conception des encodeurs de capteurs optiques rotatifs (Optical rotation sensors - ORSs) est basée sur trois exigences importantes, soient la fiabilité, la linéarité, et l’exactitude de mesures. Ces capteurs intégrés dans le système de vol doivent être intelligents. Pour la fiabilité, la réponse du capteur est calculée à partir du ratio des deux puissances optiques ou celui de la différence divisée par la somme de ces deux puissances optiques. Cependant, pour la linéarité, la réponse du capteur consiste en une relation linéaire avec le paramètre à mesurer qui est l’angle de rotation. Quant à l’exactitude, l’erreur doit être moins de 1% sur toute la gamme de mesures. De plus, pour un capteur intelligent, le capteur basé sur des circuits analogiques, les convertisseurs au monde numérique et l’étape de démodulation doivent être emballés dans un boîtier commun. Dans un premier prototype, un capteur de déplacement ratio-métrique, auto-référant, analogique et optique a été proposé pour les applications avioniques. La position de rotation est déterminée par le ratio de deux puissances lumineuses réfléchie et transmise qui rendent le capteur indépendant de fluctuations de puissance. L’encodeur multi-gradient original proposé compense pour l’usage d’une source non-uniforme.----------ABSTRACT This thesis is on novel optical sensors for smart sensor system needed in flight control system (FCS) of fly-by-wire (FBW) aircraft. Displacement sensors are needed in FBW-FCS to detect pilot inceptors, actuator displacements, and flight control surface movement. Currently, the sensors used for rotary variable displacement transducers (RVDTs) are analog electronic sensors, hence an electronic interface is needed for demodulation and digitization of analog signals. As a result, long twisted wires are drawn from the sensor to the flight control computer (FCC) interface which are heavy and susceptible to electromagnetic interference (EMI) and lightning strike. By proposing smart optical sensors, we aim to reduce the aircraft weight to decrease the fuel usage towards a greener environment, reduce EMI, and protect the aircraft against a lightning strike by using fewer metallic parts. The encoders of the optical rotation sensors (ORS) are designed based on three important requirements of reliability, linearity, and accuracy. In addition, they must be smart sensors to be integrated into the smart sensor system needed in FBW aircraft. For reliability requirements, the designed sensor response is the ratio of two optical powers or the ratio of the difference to the sum of two optical powers. For linearity requirement, the sensor response must be a linear relation with the measurand which is the rotation angle. For accuracy requirement, the error should be less than 1% over the full range. In addition, for a smart sensor, the analog sensor and the electronics for digitization and demodulation have to be packaged into a single housing.In the first design, an optical, analog, self-referencing, ratio-metric, smart displacement sensor is proposed for avionic applications. The position of rotation is determined by an encoder by the ratio of the transmitted and reflected light powers, which makes the sensor independent of power fluctuations. A single multi-gradient encoder design compensates for the use of a non-uniform source. An anti-reflection coated glass window with the outer diameter of 27mm is used with an encoder pattern mapped on it using aluminum deposition. The experimental results show that the ratio of the transmitted and reflected powers has an accuracy of 0.53% over the full range, matching the specifications for avionic applications

Small Fixed-wing Aerial Positioning Using Inter-vehicle Ranging Combined with Visual Odometry

There has been increasing interest in developing the ability for small unmanned aerial systems (SUAS) to be able to operate in environments where GPS is not available. This research considers the case of a larger aircraft loitering above a smaller GPS-denied SUAS. This larger aircraft is assumed to have greater resources which can overcome the GPS jamming and provide range information to the SUAS flying a mission below. This research demonstrates that using a ranging update combined with an aircraft motion model and visual odometry can greatly improve the accuracy of a SUASs estimated position in a GPS-denied environment

3D printing reinforced concrete structures

This study aims to investigate a 3D printing method to directly incorporate continuous reinforcement into concrete structures. The ability to design and produce complex structures with optimized topographical configuration can be used to reduce potential material waste while maintaining the required structural strength. Furthermore, the ability to actively incorporate reinforcement into printed members substantially reduces potential labor requirements and eliminates the need to set up formwork. The study began its initial approach with a manual extrusion process containing reinforcement to observe the necessary constraints required to achieve a printing system with this functionality. The second stage of development was designing a preliminary 3D printer with an auger-based extrusion system using a dual-entrance nozzle with the capacity to extrude concrete containing shaped reinforcement. The third phase consisted of controlled testing to simulate the impacts of extrusion rate and elapsed time on the final bond capacity of cured, printed specimens. A 3D printing platform with a three-axis printing bed was developed with an embedded printing sequence to synchronize the extrusion of concrete and the insertion of the reinforcement. Various combinations of concrete mixes and types of reinforcement were investigated to produce self-sustaining, printed reinforced concrete members. The preliminary results have shown that the quality of printed reinforced specimens decreases as the extrusion speeds increase. The current results do not indicate any significant impacts on bond capacity by varying extrusion rates and elapsed times”--Abstract, page iii

Aeronautical engineering: A continuing bibliography with indexes (supplement 249)

This bibliography lists 637 reports, articles, and other documents introduced into the NASA scientific and technical information system in November, 1988. Subject coverage includes: design, construction and testing of aircraft and aircraft engines; aircraft components, equipment and systems; ground support systems; and theoretical and applied aspects of aerodynamics and general fluid dynamics

Microrobots for wafer scale microfactory: design fabrication integration and control.

Future assembly technologies will involve higher automation levels, in order to satisfy increased micro scale or nano scale precision requirements. Traditionally, assembly using a top-down robotic approach has been well-studied and applied to micro-electronics and MEMS industries, but less so in nanotechnology. With the bloom of nanotechnology ever since the 1990s, newly designed products with new materials, coatings and nanoparticles are gradually entering everyone’s life, while the industry has grown into a billion-dollar volume worldwide. Traditionally, nanotechnology products are assembled using bottom-up methods, such as self-assembly, rather than with top-down robotic assembly. This is due to considerations of volume handling of large quantities of components, and the high cost associated to top-down manipulation with the required precision. However, the bottom-up manufacturing methods have certain limitations, such as components need to have pre-define shapes and surface coatings, and the number of assembly components is limited to very few. For example, in the case of self-assembly of nano-cubes with origami design, post-assembly manipulation of cubes in large quantities and cost-efficiency is still challenging. In this thesis, we envision a new paradigm for nano scale assembly, realized with the help of a wafer-scale microfactory containing large numbers of MEMS microrobots. These robots will work together to enhance the throughput of the factory, while their cost will be reduced when compared to conventional nano positioners. To fulfill the microfactory vision, numerous challenges related to design, power, control and nanoscale task completion by these microrobots must be overcome. In this work, we study three types of microrobots for the microfactory: a world’s first laser-driven micrometer-size locomotor called ChevBot，a stationary millimeter-size robotic arm, called Solid Articulated Four Axes Microrobot (sAFAM), and a light-powered centimeter-size crawler microrobot called SolarPede. The ChevBot can perform autonomous navigation and positioning on a dry surface with the guidance of a laser beam. The sAFAM has been designed to perform nano positioning in four degrees of freedom, and nanoscale tasks such as indentation, and manipulation. And the SolarPede serves as a mobile workspace or transporter in the microfactory environment

Dynamic Characterisation of the Head-Media Interface in Hard Disk Drives using Novel Sensor Systems

Hard disk drives function perfectly satisfactorily when used in a stable environment, but in certain applications they are subjected to shock and vibration. During the work reported in this thesis it has been found that when typical hard disk drives are subjected lo vibration, data transfer failure is found to be significant at frequencies between 440Hz and 700Hz, at an extreme, failing at only Ig of sinusoidal vibration. These failures can largely be attributed to two key components: the suspension arm and the hard disk. At non-critical frequencies of vibration the typical hard disk drive can reliably transfer data whilst subjected to as much as 45g. When transferring data to the drive controller, the drive's operations are controlled and monitored using BIOS commands. Examining the embedded error signals proved that the drive predominantly failed due lo tracking errors. Novel piezo-electric sensors have been developed to measure unobtrusively suspension arm and disk motion, the results from which show the disk to be the most significant failure mechanism, with its First mode of resonance at around 440Hz. The suspension arm movement has been found to be greatest at IkHz. Extensive modelling of the flexure of the disk, clamped and unclamped, has been undertaken using finite element analysis. The theoretical modelling strongly reinforces the empirical results presented in this thesis. If suspension arm movement is not directly coupled with disk movement then a flying height variation is created. This, together with tracking variations, leads to data transfer corruption. This has been found to occur at IkHz and 2kHz. An optical system has been developed and characterised for a novel and inexpensive flying height measurement system using compact disc player technology

NASA Tech Briefs, April 2011

Topics covered include: Amperometric Solid Electrolyte Oxygen Microsensors with Easy Batch Fabrication; Two-Axis Direct Fluid Shear Stress Sensor for Aerodynamic Applications; Target Assembly to Check Boresight Alignment of Active Sensors; Virtual Sensor Test Instrumentation; Evaluation of the Reflection Coefficient of Microstrip Elements for Reflectarray Antennas; Miniaturized Ka-Band Dual-Channel Radar; Continuous-Integration Laser Energy Lidar Monitor; Miniaturized Airborne Imaging Central Server System; Radiation-Tolerant, SpaceWire-Compatible Switching Fabric; Small Microprocessor for ASIC or FPGA Implementation; Source-Coupled, N-Channel, JFET-Based Digital Logic Gate Structure Using Resistive Level Shifters; High-Voltage-Input Level Translator Using Standard CMOS; Monitoring Digital Closed-Loop Feedback Systems; MASCOT - MATLAB Stability and Control Toolbox; MIRO Continuum Calibration for Asteroid Mode; GOATS Image Projection Component; Coded Modulation in C and MATLAB; Low-Dead-Volume Inlet for Vacuum Chamber; Thermal Control Method for High-Current Wire Bundles by Injecting a Thermally Conductive Filler; Method for Selective Cleaning of Mold Release from Composite Honeycomb Surfaces; Infrared-Bolometer Arrays with Reflective Backshorts; Commercialization of LARC (trade mark) -SI Polyimide Technology; Novel Low-Density Ablators Containing Hyperbranched Poly(azomethine)s; Carbon Nanotubes on Titanium Substrates for Stray Light Suppression; Monolithic, High-Speed Fiber-Optic Switching Array for Lidar; Grid-Tied Photovoltaic Power System; Spectroelectrochemical Instrument Measures TOC; A Miniaturized Video System for Monitoring Drosophila Behavior; Hydrofocusing Bioreactor Produces Anti-Cancer Alkaloids; Creep Measurement Video Extensometer; Radius of Curvature Measurement of Large Optics Using Interferometry and Laser Tracker n-B-pi-p Superlattice Infrared Detector; Safe Onboard Guidance and Control Under Probabilistic Uncertainty; General Tool for Evaluating High-Contrast Coronagraphic Telescope Performance Error Budgets; Hidden Statistics of Schroedinger Equation; Optimal Padding for the Two-Dimensional Fast Fourier Transform; Spatial Query for Planetary Data; Higher Order Mode Coupling in Feed Waveguide of a Planar Slot Array Antenna; Evolutionary Computational Methods for Identifying Emergent Behavior in Autonomous Systems; Sampling Theorem in Terms of the Bandwidth and Sampling Interval; Meteoroid/Orbital Debris Shield Engineering Development Practice and Procedure; Self-Balancing, Optical-Center-Pivot, Fast-Steering Mirror; Wireless Orbiter Hang-Angle Inclinometer System; and Internal Electrostatic Discharge Monitor - IESDM