Tech Briefs

First-Order Theory of Control of Motion of a Crane and Load

Suitably modulated motion of the crane could prevent swinging of the load.

A first-order mathematical model has been developed in a theoretical study of the dynamics of a load suspended by a cable from a crane that moves along a straight track. The model is the basis of a proposed method of computer control of the velocity as well as the position of the crane to minimize or prevent swinging of the load. (Traditionally, only the position of the crane is controlled; there is no engineering provision against swinging of the load.) Velocity and position control to prevent swinging would be highly desirable, especially in situations in which there are requirements for precise placement of large loads and/or the delays incurred in waiting for damping of pendulum oscillations of loads are unacceptable. Because most modern cranes are already controlled by computers and include position-indicating control subsystems, the implementation of this method of control would entail little or no additional equipment and thus should be relatively inexpensive.

Posted in: Briefs, TSP, Mechanical Components, Mechanics, Mathematical models, Industrial vehicles and equipment
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A Personal-Computer-Based Physiological Training System

This system is an improved means of implementing autogenic-feedback training exercise.

The Autogenic Clinical/Lab System (ACLS) is a personal-computer-based instrumentation system for physiological training. This system can be used to implement a program of multiparameter physiological conditioning known as autogenic-feedback training exercise (AFTE).

Posted in: Briefs, Electronics & Computers, Education, Education and training, Test equipment and instrumentation
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Reconfigurable Arrays of Transistors for Evolvable Hardware

Transistors in hierarchical arrays would be connected according to hierarchical control signals.

Very-large-scale integrated (VLSI) circuits containing electronically reconfigurable arrays of transistors have been proposed as means to implement a forthcoming generation of a special class of digital/analog electronic circuits. The class in question is a subclass of advanced electronic and other equipment of a type called "evolvable hardware" (EHW). The major distinguishing feature of EHW is that under the direction of genetic and/or other evolutionary algorithms, its configuration and thus its functionality can be made to evolve until it exhibits a desired behavior or adapts to the environment in a prescribed way. An EHW system is said to be extrinsic if its evolution is directed and evaluated by a computer or other external system. An EHW system is said to be intrinsic if it includes an electronic or other subsystem that automatically directs and evaluates its evolution.

Posted in: Briefs, TSP, Electronics & Computers, Electronic equipment, Transistors, Hardware
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Active Tactile Display Device for Reading by a Blind Person

Heights of numerous pins would be varied to form patterns that could be felt.

A proposed active tactile display device would present textual and graphical information to a blind person. The concept of this device is a byproduct of recent research on the use of electroactive polymers to generate forces and displacements in novel robotic actuators.

Posted in: Briefs, TSP, Electronics & Computers, Human factors, Displays
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Program Automates Management of IBM VM Computer Systems

The VM Automated System computer program was developed to satisfy a need for efficient management of operations in a large client/server computer network that includes multiple mainframe computers and multiple local-area subnetworks. Functions performed by the program include the following:

Posted in: Briefs, Information Sciences, Computer software and hardware, Systems management, Automation
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System for Monitoring the Environment of a Spacecraft Launch

A system that includes sensors and computers that communicate via an intranet enables both real-time monitoring and subsequent analysis of acoustic, overpressure, and thermal aspects of a spacecraft-launch environment and the structural response (vibration and strain) to that environment. The sensors include microphones, accelerometers, strain gauges, and a thermocouple attached to a cantilever beam mounted vertically on the roof of a building near a launch pad. The sensors are connected via cables to signal conditioners inside the building. The conditioned sensor outputs are coupled to a digital audio tape (DAT) recorder that is monitored and controlled by a computer denoted the "remote" computer. A host computer in a different building communicates with the remote computer via the intranet, using the Transmission Control Protocol/Internet Protocol. Ambient test conditions can be monitored in real time before a launch. Last-minute adjustments can be accomplished remotely and dynamically. A few minutes before the launch, the DAT recorder is turned on to record launch events. Data can be monitored in real time during the launch. After the launch, data can be copied from the DAT recorder onto the remote computer and then transferred to the host computer for plotting and analysis.

Posted in: Briefs, Electronics & Computers, Analysis methodologies, Sensors and actuators, Launch vehicles, Spacecraft
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Measurement of Stresses and Strains in Muscles and Tendons

Small, electrically and chemically neutral sensors would be implanted surgically.

Miniature fiber-optic-coupled sensors based on optically excited, self-resonant microbeams are being developed for measuring stresses and strains within muscle fascicles and tendons. These sensors could be used in medical and biological research on humans and other animals, or to obtain data for the design of lifelike robots.

Posted in: Briefs, TSP, Test & Measurement, Fiber optics, Sensors and actuators, Medical, health, and wellness
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Optical Measurement of Temperatures in Muscles and Tendons

Small, electrically and chemically neutral sensors would be implanted surgically.

Miniature fiber-optic-coupled sensors based on optically excited, self-resonant microbeams have been proposed for measuring temperatures within muscle fascicles and tendons. The proposed sensors could be used in medical and biological research on humans and other animals. The proposed sensors would be variants of those described in several previous articles in NASA Tech Briefs: "Proximity Measurement of Pressure and Temperature" (NPO-20223), Vol. 22, No. 1 (January 1998), page 48; and "Measurement of Stresses and Strains in Muscles and Tendons" elsewhere in this issue.

Posted in: Briefs, TSP, Test & Measurement, Fiber optics, Sensors and actuators, Medical, health, and wellness
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Small Low-Temperature Thermometer With Nanokelvin Resolution

The magnetic field is generated by permanent magnets instead of a solenoid.

An improved high-resolution thermometer (HRT) for use in scientific experiments at temperatures

Posted in: Briefs, TSP, Test & Measurement, Measurements, Test equipment and instrumentation
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Heterodyne Interferometer With Phase-Modulated Carrier

Resolution and working distance are increased.

A heterodyne optical interferometer of a type used to measure small displacements can be augmented to suppress a phenomenon, called "self-interference," that tends to limit the achievable resolution and working distance and can even render the interferometer inoperable. The technique for suppressing self-interference can be implemented by use of commercial off-the-shelf optoelectronic and electro-optical components, and does not degrade the fundamental operation of the interferometer.

Posted in: Briefs, TSP, Electronics & Computers, Measurements, Test equipment and instrumentation
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