Special Coverage

Converting from Hydraulic Cylinders to Electric Actuators
Automating Optimization and Design Tasks Across Disciplines
Vibration Tables Shake Up Aerospace and Car Testing
Supercomputer Cooling System Uses Refrigerant to Replace Water
Computer Chips Calculate and Store in an Integrated Unit
Electron-to-Photon Communication for Quantum Computing
Mechanoresponsive Healing Polymers
Variable Permeability Magnetometer Systems and Methods for Aerospace Applications
Evaluation Standard for Robotic Research

Shaker Fatigue Testing of a Turbine Engine Compressor Blade

Linear dynamic finite-element analysis was used to optimize testing. Hamler Test and Analysis (HTA) provides testing, design, and finite-element analysis (FEA) consulting services, specializing in vibration measurement and experimental vibration analysis tools such as tap testing, modal analysis, operating deflection shapes analysis, and rotating machinery analysis. HTA was contracted to perform physical fatigue testing of a compressor blade from a stationary gas turbine engine used for power generation. Electrodynamic shaker testing was required to verify the client’s analytical vibratory high-cycle fatigue life prediction methodology. The first phase of the shaker testing involved vibrating several blades to failure at the first bending mode, and the second phase involved testing several blades to failure at the first torsion mode.

Posted in: Briefs, Physical Sciences, Propellers and rotors, Finite element analysis, Fatigue, Vibration, Compressors, Gas turbines

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Dynamic Stability and Gravitational Balancing of Multiple Extended Bodies

Feasibility of a non-invasive compensation scheme was analyzed for precise positioning of a massive extended body in free fall using gravitational forces influenced by surrounding source masses in close proximity. The N-body problem of classical mechanics is a paradigm used to gain insight into the physics of the equivalent N-body problem subject to control forces.

Posted in: Briefs, Physical Sciences, Mathematical models, Attitude control, Vehicle dynamics

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Simulation of Stochastic Processes by Coupled ODE-PDE

A document discusses the emergence of randomness in solutions of coupled, fully deterministic ODE-PDE (ordinary differential equations-partial differential equations) due to failure of the Lipschitz condition as a new phenomenon. It is possible to exploit the special properties of ordinary differential equations (represented by an arbitrarily chosen, dynamical system) coupled with the corresponding Liouville equations (used to describe the evolution of initial uncertainties in terms of joint probability distribution) in order to simulate stochastic processes with the proscribed probability distributions. The important advantage of the proposed approach is that the simulation does not require a random-number generator.

Posted in: Briefs, TSP, Information Sciences, Computer simulation, Statistical analysis

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Cluster Inter-Spacecraft Communications

A document describes a radio communication system being developed for exchanging data and sharing data-processing capabilities among spacecraft flying in formation. The system would establish a high-speed, low- latency, deterministic loop communication path connecting all the spacecraft in a cluster. The system would be a wireless version of a ring bus that complies with the Institute of Electrical and Electronics Engineers (IEEE) standard 1393 (which pertains to a spaceborne fiber-optic data bus enhancement to the IEEE standard developed at NASA’s Jet Propulsion Laboratory). Every spacecraft in the cluster would be equipped with a ring-bus radio transceiver. The identity of a spacecraft would be established upon connection into the ring bus, and the spacecraft could be at any location in the ring communication sequence.

Posted in: Briefs, TSP, Electronics & Computers, Architecture, Data exchange, Wireless communication systems, Spacecraft

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Low-Impact Mating System for Docking Spacecraft

A document describes a low-impact mating system suitable for both docking (mating of two free-flying spacecraft) and berthing (in which a robot arm in one spacecraft positions an object for mating with either spacecraft). The low-impact mating system is fully androgynous: it mates with a copy of itself, i.e., all spacecraft and other objects to be mated are to be equipped with identical copies of the system. This aspect of the design helps to minimize the number of unique parts and to standardize and facilitate mating operations. The system includes a closed-loop feedback control subsystem that actively accommodates misalignments between mating spacecraft, thereby attenuating spacecraft dynamics and mitigating the need for precise advance positioning of the spacecraft.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Adaptive control, Architecture, Connectors and terminals, Spacecraft

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Non-Destructive Evaluation of Materials via Ultraviolet Spectroscopy

A document discusses the use of ultraviolet spectroscopy and imaging for the non-destructive evaluation of the degree of cure, aging, and other properties of resin-based composite materials. This method can be used in air, and is portable for field use. This method operates in reflectance, absorbance, and luminescence modes.

Posted in: Briefs, TSP, Physical Sciences, Spectroscopy, Composite materials, Resins, Non-destructive tests, Test procedures

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Gold-on-Polymer-Based Sensing Films for Detection of Organic and Inorganic Analytes in the Air

A document discusses gold-on-polymer as one of the novel sensor types developed for part of the sensor development task. Standard polymer- carbon composite sensors used in the JPL Electronic Nose (ENose) have been modified by evaporating 15 nm of metallic gold on the surface. These sensors have been shown to respond to alcohols, aromatics, ammonia, sulfur dioxide, and elemental mercury in the parts-per-million and parts-per-billion concentration ranges in humidified air.

Posted in: Briefs, TSP, Physical Sciences, Sensors and actuators, Air pollution, Chemicals, Composite materials, Polymers

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Genetic Algorithm Optimizes Q-LAW Control Parameters

A document discusses a multi-objective, genetic algorithm designed to optimize Lyapunov feedback control law (Q-law) parameters in order to efficiently find Pareto- optimal solutions for low-thrust trajectories for electronic propulsion systems. These would be propellant-optimal solutions for a given flight time, or flight time optimal solutions for a given propellant requirement. The approximate solutions are used as good initial solutions for high-fidelity optimization tools. When the good initial solutions are used, the high-fidelity optimization tools quickly converge to a locally optimal solution near the initial solution.

Posted in: Briefs, TSP, Information Sciences, Trajectory control, Mathematical models, Optimization, Propellants, Spacecraft fuel

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Quantum-Inspired Maximizer

A report discusses an algorithm for a new kind of dynamics based on a quantum-classical hybrid-quantum-inspired maximizer. The model is represented by a modified Madelung equation in which the quantum potential is replaced by different, specially chosen “computational” potential. As a result, the dynamics attains both quantum and classical properties: it preserves superposition and entanglement of random solutions, while allowing one to measure its state variables, using classical methods. Such optimal combination of characteristics is a perfect match for quantum-inspired computing. As an application, an algorithm for global maximum of an arbitrary integrable function is proposed. The idea of the proposed algorithm is very simple: based upon the Quantum-inspired Maximizer (QIM), introduce a positive function to be maximized as the probability density to which the solution is attracted. Then the larger value of this function will have the higher probability to appear.

Posted in: Briefs, TSP, Information Sciences, Mathematical models, Statistical analysis

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Vision, Software Enhancements Advance Robots

Robotics technology has made measurable strides in the last few years. Today’s robots can move with greater precision over a more flexible range of motion, while handling heavier payloads. Advances in vision systems and software are giving robots the ability to recognize and handle a wider range of parts than before, and make decisions that only humans could previously perform.

Posted in: Articles, Motion Control, Computer software and hardware, Imaging and visualization, Performance upgrades, Robotics

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