Papers by Keyword: Laser Interferometry

Abstract: Verification systems are needed for periodic verification and calibration of robots and machine tools to maintain and increase their accuracy. One of the ways to verify the volumetric accuracy of a manufacturing system is to measure the position of its head (X, Y, Z coordinates) using measurement systems that provide these results with the appropriate precision. The laser interferometer provides results with accuracy levels suitable for robot and machine tool verification applications. However, to measure the head position of manufacturing systems (X, Y, Z coordinates), the use of laser interferometers requires a prior adjustment to a reference length, since they measure incrementally. This adjustment procedure of the measurement system introduces an error in the resulting head coordinates that depends on the environmental conditions and the material of the standard element used to materialize the reference length. This paper analyzes the temperature effect in the adjustment process and how temperature errors introduced in said process affect the head 3D coordinates calculation of the Manufacturing System under inspection.

Abstract: The hydroacoustic transponder based on the principle of laser interferometry is investigated, which consists of three parts: 1) the front-end module, which is a signal receiving and pre-processing module, and consists of a laser interferometric receiver and a filter group; 2) the signal processing module, which consists of the data acquisition module and a data processing system; 3) the back-pulse module, which consists of an automatic gain adjustment module, a transmitter module and a back-transducer. We give the detailed designing flow charts of the hardware and software programs.

Abstract: The incremental hole-drilling technique was applied to determine residual stress profiles in shot-peened steel layers. The accuracy of using an enhanced Digital Speckle Pattern Interferometry technique for measuring the strain relaxation arising around the drilled holes and, consequently, the in-depth residual stress distribution induced by shot-peening, was evaluated. The experimental results were systematically compared with those determined using standard electric strain-gauges. The X-ray diffraction technique was chosen as reference due to its high accuracy to determine shot-peening residual stresses.

Abstract: In the current space program, astronaut body mass onboard spacecraft, including the International Space Station (ISS) is measured with spring-mass device. We propose a new device “Space Scale” with laser interferometry acceleration measurement and an inline force sensor with a bungee cord. This paper describes concept of Space Scale and its accuracy estimation by ground model test. Accuracy obtained in this ground test was –0.293 %, of which force sensor contributed most to error.

Abstract: This abstract presents the development of an ultra-precision motion controlled positioning stage for nanometer positioning over a working volume of 50 mm × 50 mm × 4 µm at an accuracy of better than 10 nm that is traceable to the national standards. The positioning stage is designed to use various probing systems to perform “pick and place” manipulations and scanning of large specimens, including biological. The system is comprised of a two-axis, long-range stage and a 6 degree-of-freedom (DOF) short-range stage. The long-range stage is responsible for coarse motions of up to 50 mm, while the short-range stage is responsible for correcting positioning errors generated by the long-range stage to achieve nanometer level accuracies. The system will be housed in a vacuum chamber operating at a vacuum pressure of better than 10-3 Torr. The vacuum chamber is also designed to act as an environmental chamber where different gases can be used depending on the measurement task. The initial results of the fully developed positioning stage will be presented at the conference.