For example, laser trackers and total stations are typically specified for use as a conventional laser-based spherical coordinate measurement system complying with ASME B There is not much to be gained by specifying the frequency and amplitude of measurements for a spherically mounted retroreflector resting in a static nest, if the objective is to compare the measurements to static drawing specifications.
The device is an extension of a known approach using an hexapod a Stewart-Gough platform. Depending on the signal-to-noise of the instrument, and the atmospheric turbulence, a series of periods are averaged to determine the phase.
For an instrument located on the axis of rotation, the distance would not change as the target maps out a cone. By using three, or more, electronic distance measurement EDM instruments, such as commercially available laser trackers, in an unconventional trilateration architecture, 3D coordinates of specialized retroreflector targets attached to cardinal points on a structure can be measured with absolute uncertainty of less than one part per million.
The robot is calibrated in 61 configurations and the absolute position accuracy of the robot after calibration is validated with a Faro laser tracker in about 10, robot configurations. To allow a comparison, the robot is also calibrated using the laser tracker and the robot accuracy validated in the same 10, robot configurations.
Table 2 shows information that would be useful for an engineer designing Laser tracker thesis experiment using a laser tracker distance meter. However, for quasi stationary targets, such as on a bridge, there is no need to repeat the full ambiguity measurement every time the instrument switches to the target, so the instrument can make the first measurement immediately after switching with a much shorter maximum latency.
The maximum distance may depend on the return power, so it may depend on the retroreflector size. For example, cracks exhibit a highly nonlinear response when strains are reversed from compression to tension. The American Society of Mechanical Engineers. Relative dynamic movements, such as vibrations at 30 Hz, are typically measured 10 times better, i.
An email including comments pointing this out was sent to the PPC members following the CMSC Conference,49 but was not acknowledged with a response.
The mean distance error is improved from 1. For a phase measurement system, one would like to know the nominal modulation frequency, i.
One case was found that used a Leica AT laser tracker, but it also measured deflections by measuring the elevation angle, i. In most cases, the experimenters tried to measure these deflections and vibrations using the angle measurements of a total station, i.
Significant opportunities are available in the civil, structural, mechanical, and software engineering fields, as well as expanded markets for instrument manufacturers, dimensional metrology measurement service providers, and software companies.
Only one case reported 3D measurements, using a total station. This technique has been used in a patent to Nelson et al. For example, as shown in table 1, the range specifications for present-day commercially available laser trackers is between 80 m and m.
For enhanced accuracy, the dwell time may be increased to average out noise. An argument will be made that laser trackers and total stations should begin to be thought of as DCMS.
For NDT applications, it may be desirable to measure a plurality of targets attached to the structure by switching rapidly between the targets in a sequence.
If, on the other hand, one were to have an application that lends itself to measuring in Laser tracker thesis the radial direction, for a 1D measurement, or use a combination of instruments in a trilateration architecture for a 3D measurement, the uninitiated may be led to believe that the range for commercially available instruments is limited to the published 3D specifications, and incorrectly assume the measurement cannot be performed with the instruments available.
Measurements of such accuracy open new areas for nondestructive testing and finite-element model confirmation of stiff, large-scale structures, such as buildings, bridges, cranes, boilers, tank cars, nuclear power plant containment buildings, post-tensioned concrete, and the like by measuring the response to applied loads, changes over the life of the structure, or changes following an accident, fire, earthquake, modification, etc.
Selected excerpts of the First Paper will be repeated herein. Railroad Bridges and Structural Engineering. This article, which is intended to be an introduction to NDT for the Coordinate Metrology Society CMS community, will be cumulative, so those interested in the subject should also read the First Paper, which is incorporated by reference.
The developed methods focus on using low cost measurement equipment. The sensitivity of these measurements makes it possible to measure parameters such as linearity, hysteresis, creep, symmetry, damping coefficient, and the like.Implementation of the Digital Communication System in the F/A Aircraft Gregory D.
Bigalk University of Tennessee - Knoxville This Thesis is brought to you for free and open access by the Graduate School at Trace: Tennessee Research and Creative Exchange. It has been LST Laser Spot Tracker LTD Laser Target Designator. 6 DIY Star Trackers for Perfect Night Sky Photos.
Live: World Maker Faire New York The Humble, Inspiring Magic of Maker Faire Alex Kuzmuk’s laser-cut, Arduino-driven barn door tracker.
Finally, Alex Kuzmuk in the Ukraine designed custom laser-cut doors and acrylic gears for his curved-bolt tracker. APPLIED MASS PROPERTIES IDENTIFICATION METHOD TO THE CAL POLY’S SPACECRAFT SIMULATOR A Thesis (MEMS Gyros), laser-ring gyroscopes, optical sensors such as star tracker, and/or GPS.
The accuracy of these sensors depends on their application and can vary from to A need for an inertial measurement. One case was found that used a Leica AT laser tracker, but it also measured deflections by measuring the elevation angle, i.e., like the total station cases, the measurement architecture did not exploit the higher accuracy and speed of EDM.
Jul 26, · The objective of this thesis is to develop a tracking system based on visual servo control. The mechatronic system drives a laser pointer to indicate the position of (ISS Tracker. the thesis. For further investigation though, it would be in teresting to use the "drive by sensor" modality to do online path planning along with path c orrection.
This would make A laser tracker from Leica Geosystems is a portable measurem ent system that relies on.Download