A Generalized Method for Automatic Downhand and Wirefeed Control of a Welding Robot and Positioner

A generalized method for controlling a six degree-of-freedom (DOF) robot and a two DOF positioner used for arc welding operations is described. The welding path is defined in the part reference frame, and robot/positioner joint angles of the equivalent eight DOF serial linkage are determined via an iterative solution. Three algorithms are presented: the first solution controls motion of the eight DOF mechanism such that proper torch motion is achieved while minimizing the sum-of-squares of joint displacements; the second algorithm adds two constraint equations to achieve torch control while maintaining part orientation so that welding occurs in the downhand position; and the third algorithm adds the ability to control the proper orientation of a wire feed mechanism used in gas tungsten arc (GTA) welding operations. A verification of these algorithms is given using ROBOSIM, a NASA developed computer graphic simulation software package design for robot systems development

Chironomid (Diptera: Chironomidae) Larvae as Indicators of Water Quality in Irondequoit Creek, NY

Chironomid community structure and mouthpart deformities were examined as indicators of pollution or degradation of water quality in the Irondequoit Creek watershed. Differences in Simpson\u27s diversity, taxa richness, and chironomid abundance were assessed in upper, middle, and lower creek locations to determine changes as the creek passes through increasingly populated areas. Differences in the same measures also were assessed in vegetation, mud, and gravel habitats in order to assure that any changes observed were not due to differences in chironomid community structure in dissimilar substrates. Diversity and taxa richness were highest in the upper creek and lowest in the lower creek. Abundance was highest in the middle creek. All three measures were highest in the gravel habitats and lowest in the vegetation habitats. Slight organic pollution impacts on the creek were indicated by lower diversity and richness values in the lower locations of lrondequoit Creek and by community structure differences. Mouthpart deformity comparisons were inconclusive because affected taxa were not present at all sites. This study brings into question the feasibility of using chironomid communities and deformity rates as indicators of water quality changes in the Irondequoit Creek system. Due to the high variance in chironomid distributions, a larger number of samples is needed to detect changes in chironomid communities. Other changes in sampling methods may also be necessary

ROBOSIM, a simulator for robotic systems

ROBOSIM, a simulator for robotic systems, was developed by NASA to aid in the rapid prototyping of automation. ROBOSIM has allowed the development of improved robotic systems concepts for both earth-based and proposed on-orbit applications while significantly reducing development costs. In a cooperative effort with an area university, ROBOSIM was further developed for use in the classroom as a safe and cost-effective way of allowing students to study robotic systems. Students have used ROBOSIM to study existing robotic systems and systems which they have designed in the classroom. Since an advanced simulator/trainer of this type is beneficial not only to NASA projects and programs but industry and academia as well, NASA is in the process of developing this technology for wider public use. An update on the simulators's new application areas, the improvements made to the simulator's design, and current efforts to ensure the timely transfer of this technology are presented

ROBOSIM: An intelligent simulator for robotic systems

The purpose of this paper is to present an update of an intelligent robotics simulator package, ROBOSIM, first introduced at Technology 2000 in 1990. ROBOSIM is used for three-dimensional geometrical modeling of robot manipulators and various objects in their workspace, and for the simulation of action sequences performed by the manipulators. Geometric modeling of robot manipulators has an expanding area of interest because it can aid the design and usage of robots in a number of ways, including: design and testing of manipulators, robot action planning, on-line control of robot manipulators, telerobotic user interface, and training and education. NASA developed ROBOSIM between 1985-88 to facilitate the development of robotics, and used the package to develop robotics for welding, coating, and space operations. ROBOSIM has been further developed for academic use by its co-developer Vanderbilt University, and has been in both classroom and laboratory environments for teaching complex robotic concepts. Plans are being formulated to make ROBOSIM available to all U.S. engineering/engineering technology schools (over three hundred total with an estimated 10,000+ users per year)

Simulation-based intelligent robotic agent for Space Station Freedom

A robot control package is described which utilizes on-line structural simulation of robot manipulators and objects in their workspace. The model-based controller is interfaced with a high level agent-independent planner, which is responsible for the task-level planning of the robot's actions. Commands received from the agent-independent planner are refined and executed in the simulated workspace, and upon successful completion, they are transferred to the real manipulators

Robot graphic simulation testbed

The objective of this research was twofold. First, the basic capabilities of ROBOSIM (graphical simulation system) were improved and extended by taking advantage of advanced graphic workstation technology and artificial intelligence programming techniques. Second, the scope of the graphic simulation testbed was extended to include general problems of Space Station automation. Hardware support for 3-D graphics and high processing performance make high resolution solid modeling, collision detection, and simulation of structural dynamics computationally feasible. The Space Station is a complex system with many interacting subsystems. Design and testing of automation concepts demand modeling of the affected processes, their interactions, and that of the proposed control systems. The automation testbed was designed to facilitate studies in Space Station automation concepts

A generalized method for multiple robotic manipulator programming applied to vertical-up welding

The application is described of a weld programming algorithm for vertical-up welding, which is frequently desired for variable polarity plasma arc welding (VPPAW). The Basic algorithm performs three tasks simultaneously: control of the robotic mechanism so that proper torch motion is achieved while minimizing the sum-of-squares of joint displacement; control of the torch while the part is maintained in a desirable orientation; and control of the wire feed mechanism location with respect to the moving welding torch. Also presented is a modification of this algorithm which permits it to be used for vertical-up welding. The details of this modification are discussed and simulation examples are provided for illustration and verification

DNA/RNA Degradation Rate in Long Term Fixed Museum Specimens

In today’s research driven society, it has become commonplace for institutions to rely upon DNA and RNA extraction techniques to help obtain genomic data from old specimens. Generally, specimens were commonly preserved for future gross examination and/or teaching. Using histological examination of specimens from museum jars from the Pathology Department at the Indiana University School of Medicine, the sequential and chronological degradation of DNA and RNA has been studied. We examined gross specimens from nine decades from 1920 until 2000. We evaluated histologic preservation of kidney, liver, heart, lung, spleen, uterus, and brain for nuclear structure in these samples. Nuclear preservation was based on amount of nuclei per 20x microscopic field and the crispness of the nuclear membrane and internal features. The nuclei in high lipid tissues such as the brain were found to degrade at a quicker rate than dense tissues such as the heart and uterus. Our study has shown specimens preserved beyond fifty years were likely to have little to no nuclei left, thus indicating that there was little to no DNA and RNA remaining. This technique of histologic evaluation first is an important finding and a general guideline which may save research institutions from the expensive process of DNA and RNA extraction

Glad News no. 2: a Collection of Sacred Songs, Both New and Old, for the Church, the Sunday-School, the Revival Meeting, the Singing School, the Singing Convention, and All Kinds of Religious Work and Worship

Glad News no. 2, edited by George W. Bacon, Alfred E. Helton, and W. N. Cook, published by the Teachers\u27 Music Publishing Co. in Hudson, NC, and printed by the Armstrong Printing Co. Shape Note Hymnal with 7 shape notation. Includes Index. Collection contains 2 copies.https://digitalcommons.gardner-webb.edu/shape-note-collection/1008/thumbnail.jp