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At least 91 records · Page 5

Application of Sequential Quadratic Programming to Minimize Smart Active Flap Rotor Hub Loads

In an analytical study, SMART active flap rotor hub loads have been minimized using nonlinear programming constrained optimization methodology. The recently developed NLPQLP system (Schittkowski, 2010) that employs Sequential Quadratic Programming (SQP) as its core algorithm was embedded into a driver code (NLP10x10) specifically designed to minimize active flap rotor hub loads (Leyland, 2014). Three types of practical constraints on the flap deflections have been considered. To validate the current application, two other optimization methods have been used: i) the standard, linear unconstrained method, and ii) the nonlinear Generalized Reduced Gradient (GRG) method with constraints. The new software code NLP10x10 has been systematically checked out. It has been verified that NLP10x10 is functioning as desired. The following are briefly covered in this paper: relevant optimization theory; implementation of the capability of minimizing a metric of all, or a subset, of the hub loads as well as the capability of using all, or a subset, of the flap harmonics; and finally, solutions for the SMART rotor. The eventual goal is to implement NLP10x10 in a real-time wind tunnel environment.

HUB LOADS

A Framework for Testing Automated Detection, Diagnosis, and Remediation Systems on the Smart Grid

America's electrical grid is currently undergoing a multi-billion dollar modernization effort aimed at producing a highly reliable critical national infrastructure for power - a Smart Grid. While the goals for the Smart Grid include upgrades to accommodate large quantities of clean, but transient, renewable energy and upgrades to provide customers with real-time pricing information, perhaps the most important objective is to create an electrical grid with a greatly increased robustness.

autonomous detection, diagnosis, and remediation (

Testing and Evaluation of Multifunctional Smart Coatings

A smart coating system, based on pH sensitive microcontainers (microparticles and microcapsules) has been developed. Various corrosion inhibitors have been encapsulated and incorporated into commercial and formulated coatings to test the functionality imparted on the coating by the incorporation of the inhibitor microcontainers. Coated carbon steel and aluminum alloy panels were tested using salt immersion, salt fog, and coastal atmospheric exposure conditions. This paper provides the details on coating sample preparation, evaluation methods, as well as test results of the inhibiting function of smart coatings.

Testing and Evaluation

LPV Modeling and Control for Active Flutter Suppression of a Smart Airfoil

In this paper, a novel technique of linear parameter varying (LPV) modeling and control of a smart airfoil for active flutter suppression is proposed, where the smart airfoil has a groove along its chord and contains a moving mass that is used to control the airfoil pitching and plunging motions. The new LPV modeling technique is proposed that uses mass position as a scheduling parameter to describe the physical constraint of the moving mass, in addition the hard constraint at the boundaries is realized by proper selection of the parameter varying function. Therefore, the position of the moving mass and the free stream airspeed are considered the scheduling parameters in the study. A state-feedback based LPV gain-scheduling controller with guaranteed H infinity performance is presented by utilizing the dynamics of the moving mass as scheduling parameter at a given airspeed. The numerical simulations demonstrate the effectiveness of the proposed LPV control architecture by significantly improving the performance while reducing the control effort.

Smart Airfoil

Shadow Mode Assessment Using Realistic Technologies for the National Airspace System (SMART NAS) Test Bed Development

This paper is devoted to describing the development of a new NASA air traffic management simulation and testing system called the Shadow Mode Assessment using Realistic Technologies for the National Airspace System (SMART NAS) test bed. The test bed is a major activity of NASA’s air traffic management research portfolio and fills important gaps in the air traffic community’s simulation and testing needs for allowing more efficient acceleration and acceptance of NextGen and far-term concepts and technologies. The test bed will allow testing and validation in a realistic environment and provide rapid near-real-time “what-if” capability for air traffic management and airline decision support based on comprehensive real-time data feeds. The vision, requirements of the SMART NAS test bed and the effort for developing the test bed architecture are discussed. Finally, the five-year development plan is outlined.

simulation platform

Smart Sensor Systems for Human Health and Environmental Applications

Sensors and sensor systems are central to providing improved awareness of an individual's health state and surroundings. This presentation describes efforts to develop Smart Sensor Systems for a range of health and safety applications moving towards distributed intelligence. This includes efforts to develop a human health breath monitoring system using this microsensor Smart Sensor System approach. The same core technology can be used for a range of applications related to improved human health and environmental monitoring. Other examples of human health relevant technology development will also be given.

Smart Sensors Health

Multispectral data acquisition and classification - Computer modeling for smart sensor design

In this paper a model of the processes involved in multispectral remote sensing and data classification is developed as a tool for designing and evaluating smart sensors. The model has both stochastic and deterministic elements and accounts for solar radiation, atmospheric radiative transfer, surface reflectance, sensor spectral reponses, and classification algorithms. Preliminary results are presented which indicate the validity and usefulness of this approach. Future capabilities of smart sensors will ultimately be limited by the accuracy with which multispectral remote sensing processes and their error sources can be computationally modeled.

Park, S. K.

Space Missions for Automation and Robotics Technologies (SMART) Program

NASA is currently considering the establishment of a Space Mission for Automation and Robotics Technologies (SMART) Program to define, develop, integrate, test, and operate a spaceborne national research facility for the validation of advanced automation and robotics technologies. Initially, the concept is envisioned to be implemented through a series of shuttle based flight experiments which will utilize telepresence technologies and real time operation concepts. However, eventually the facility will be capable of a more autonomous role and will be supported by either the shuttle or the space station. To ensure incorporation of leading edge technology in the facility, performance capability will periodically and systematically be upgraded by the solicitation of recommendations from a user advisory group. The facility will be managed by NASA, but will be available to all potential investigators. Experiments for each flight will be selected by a peer review group. Detailed definition and design is proposed to take place during FY 86, with the first SMART flight projected for FY 89.

Cliffone, D. L.

Space missions for automation and robotics technologies (SMART) program

The motivations, features and expected benefits and applications of the NASA SMART program are summarized. SMART is intended to push the state of the art in automation and robotics, a goal that Public Law 98-371 mandated be an inherent part of the Space Station program. The effort would first require tests of sensors, manipulators, computers and other subsystems as seeds for the evolution of flight-qualified subsystems. Consideration is currently being given to robotics systems as add-ons to the RMS, MMU and OMV and a self-contained automation and robotics module which would be tended by astronaut visits. Probable experimentation and development paths that would be pursued with the equipment are discussed, along with the management structure and procedures for the program. The first hardware flight is projected for 1989.

Ciffone, D. L.

Smart structures research program at Virginia Tech

A review of the smart structures and avionics research and teaching program that started in 1979 at Virginia Tech is described. Current smart structures research include major efforts in the development of embedded and attached optical fiber and acoustic fiber sensors for cure monitoring, in-service lifetime structural testing, nondestructive evaluation, and impact and damage detection and analysis; of gradual material degradation; sensor signal multiplexing, processing and data handling to achieve near real-time distributed structural analysis; and the integration of embedded sensors, actuators and control electronics to achieve controlled structural response. Special campus facilities used for this work include an optical fiber fabrication facility, an autoclave for composite structure fabrication and curing, and laboratories for optical fiber sensor development, materials response and nondestructive evaluation, structural control testing and computer engineering.

Claus, R. O.

Optical signal processing of spatially distributed sensor data in smart structures

Smart structures which contain dense two- or three-dimensional arrays of attached or embedded sensor elements inherently require signal multiplexing and processing capabilities to permit good spatial data resolution as well as the adequately short calculation times demanded by real time active feedback actuator drive circuitry. This paper reports the implementation of an in-line optical signal processor and its application in a structural sensing system which incorporates multiple discrete optical fiber sensor elements. The signal processor consists of an array of optical fiber couplers having tailored s-parameters and arranged to allow gray code amplitude scaling of sensor inputs. The use of this signal processor in systems designed to indicate the location of distributed strain and damage in composite materials, as well as to quantitatively characterize that damage, is described. Extension of similar signal processing methods to more complicated smart materials and structures applications are discussed.

Bennett, K. D.

Sensor technology for smart structures

Advanced aerospace structures are discussed that will very likely be fabricated with integral sensors, actuators, and microprocessors for monitoring and dynamic control of configuration. The concept of 'smart structures' integrates fiber-optic sensor technology with advanced composite materials, whereby the optical fibers are embedded in a composite material and provide internal sensing capability for monitoring parameters which are important for the safety, performance, and reliability of the material and the structure. Along with other research facilities, NASA has initiated a cooperative program to design, fabricate, and test composite trusses, tubes, and flat panels with embedded optical fibers for testing and developing prototype smart structures. It is shown that fiber-optic sensor technology can be combined with advanced material and structure concepts to produce a new class of materials with internal sensors for health monitoring of structures.

Rogowski, R. S.

System requirements specification for SMART structures mode

Specified here are the functional and informational requirements for software modules which address the geometric and data modeling needs of the aerospace structural engineer. The modules are to be included as part of the Solid Modeling Aerospace Research Tool (SMART) package developed for the Vehicle Analysis Branch (VAB) at the NASA Langley Research Center (LaRC). The purpose is to precisely state what the SMART Structures modules will do, without consideration of how it will be done. Each requirement is numbered for reference in development and testing.

Source record

Quantification of uncertainties in the performance of smart composite structures

A composite wing with spars, bulkheads, and built-in control devices is evaluated using a method for the probabilistic assessment of smart composite structures. Structural responses (such as change in angle of attack, vertical displacements, and stresses in regular plies with traditional materials and in control plies with mixed traditional and actuation materials) are probabilistically assessed to quantify their respective scatter. Probabilistic sensitivity factors are computed to identify those parameters that have a significant influence on a specific structural response. Results show that the uncertainties in the responses of smart composite structures can be quantified. Responses such as structural deformation, ply stresses, frequencies, and buckling loads in the presence of defects can be reliably controlled to satisfy specified design requirements.

Shiao, Michael C.

Launch vehicle flight control augmentation using smart materials and advanced composites (CDDF Project 93-05)

The Marshall Space Flight Center has a rich heritage of launch vehicles that have used aerodynamic surfaces for flight stability such as the Saturn vehicles and flight control such as on the Redstone. Recently, due to aft center-of-gravity locations on launch vehicles currently being studied, the need has arisen for the vehicle control augmentation that is provided by these flight controls. Aerodynamic flight control can also reduce engine gimbaling requirements, provide actuator failure protection, enhance crew safety, and increase vehicle reliability, and payload capability. In the Saturn era, NASA went to the Moon with 300 sq ft of aerodynamic surfaces on the Saturn V. Since those days, the wealth of smart materials and advanced composites that have been developed allow for the design of very lightweight, strong, and innovative launch vehicle flight control surfaces. This paper presents an overview of the advanced composites and smart materials that are directly applicable to launch vehicle control surfaces.

Barret, C.

A Coupled Layerwise Analysis of the Thermopiezoelectric Response of Smart Composite Beams Beams

Thermal effects are incorporated into previously developed discrete layer mechanics for piezoelectric composite beam structures. The updated mechanics explicitly account for the complete coupled thermoelectromechanical response of smart composite beams. This unified representation leads to an inherent capability to model both the sensory and actuator responses of piezoelectric composite beams in a thermal environment. Finite element equations are developed and numerical results are presented to demonstrate the capability of the current formulation to represent the behavior of both sensory and active smart structures under thermal loadings.

Lee, H.-J.

Solid Modeling Aerospace Research Tool (SMART) user's guide, version 2.0

The Solid Modeling Aerospace Research Tool (SMART) software package is used in the conceptual design of aerospace vehicles. It provides a highly interactive and dynamic capability for generating geometries with Bezier cubic patches. Features include automatic generation of commonly used aerospace constructs (e.g., wings and multilobed tanks); cross-section skinning; wireframe and shaded presentation; area, volume, inertia, and center-of-gravity calculations; and interfaces to various aerodynamic and structural analysis programs. A comprehensive description of SMART and how to use it is provided.

Mcmillin, Mark L.

SMART Structures User's Guide - Version 3.0

Version 3.0 of the Solid Modeling Aerospace Research Tool (SMART Structures) is used to generate structural models for conceptual and preliminary-level aerospace designs. Features include the generation of structural elements for wings and fuselages, the integration of wing and fuselage structural assemblies, and the integration of fuselage and tail structural assemblies. The highly interactive nature of this software allows the structural engineer to move quickly from a geometry that defines a vehicle's external shape to one that has both external components and internal components which may include ribs, spars, longerons, variable depth ringframes, a floor, a keel, and fuel tanks. The geometry that is output is consistent with FEA requirements and includes integrated wing and empennage carry-through and frame attachments. This report provides a comprehensive description of SMART Structures and how to use it.

Spangler, Jan L.