June 24, 2007
June 24, 2007
June 27, 2007
12.1168.1 - 12.1168.14
PRECISION POSITIONING AND VIBRATION MEASUREMENT USING INTELLIGENT INSTRUMENTATION AND SIMULATION TOOLS
The objective of this research is to detail the development of a simple and unique instrumentation for precise micro-measurement as well as vibration measurement in an integrated manufacturing set up that can be demonstrated in a student laboratory. Based on this we propose new research for a smaller embedded measurement unit. All machines have some amount of forced vibration. However, in some cases, this vibration may cause damage to the machinery. Understanding vibration in aerospace applications is critical for any system that will be exposed to vibrating motion. Previously, strain gauges and piezoelectric accelerometers have been adequate for measuring vibration. However due to the increased requirements in performance, these methods are slowly being replaced by laser-based precision instruments. One of the main reasons for this transition is the fact that the equipment in these methods must be mounted on the surface of the object being measured which can result in increasing the mass and altering the frequency, mode shape of the vibrating object. Laser technology is a non-contact measuring method and provides the resolution needed to satisfy the changing requirements.
In order to demonstrate precise positioning and motion control for creating and detecting vibrational movements, an experimental test bed was constructed. Software based simulation tools were used to control the positioning system. For vibration monitoring, the vibrating surface was discretely sampled by individual laser pulses and recorded by the position sensitive detector by the generation of pulses whose magnitudes are proportional to the instantaneous surface displacements. With a sufficiently high sampling rate, reconstruction of the vibration wave form is achieved by conducting peak detection of the resultant series of pulses. Vibration sensing by position sensing detector and vibration sensing by interferometry were the two techniques that were experimented with the new micro-positioning system. Three methods of micro-positioning and measurement were experimented; a precision encoder, an optical interferometer and an integrated vision system. Data was collected at successive points along the translation stages. The results showed that the optical interferometer and the encoder produced the most accurate results. It was also observed that significantly higher peak optical power levels of the probe laser pulses lead to proportional enhancement in the position sensitive detector response and remarkable improvement in detection sensitivity. This paper also outlines the results of the new approach in micro-positioning, displacement creation and vibration sampling in high precision machine tools. Additional results with the prediction of break-through detection in laser drilling manufacturing process has also been documented.
Positioning systems are widely used in many industrial applications such as actuators, CNC machines, automated testing, calibration, inspection as well as processes such as laser welding and cutting. Micro-positioning refers to mechanical movement where the positioning accuracy is
Shetty, D., & Hill, J., & Eppes, T. (2007, June), Precision Positioning And Vibration Measurement Using Intelligent Instrumentation And Simulation Tools Paper presented at 2007 Annual Conference & Exposition, Honolulu, Hawaii. https://peer.asee.org/2988
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