June 22, 2003
June 22, 2003
June 25, 2003
8.220.1 - 8.220.8
An Undergraduate Research Effort into Non-contact Motion Tracking
B. L. Newberry, H. Collins, and I. Lockwood
Oklahoma Christian University
Cable structures are used in many engineering applications for their ratio of high axial strength to negligible lateral stiffness. This advantageous property, however, can give rise to nonlinear oscillations that impair performance. Newberry 1 and Newberry & Perkins 2 analytically demonstrated that nonlinear modal coupling may occur between lateral and axial modes of certain cable suspensions producing premature cable failure. This coupling is most severe in submerged structures subject to fluid/cable interaction.
A prototype non-contacting sensor array, capable of submerged operation, is herein presented to allow future experimental verification of the analytical findings of Newberry and Perkins. The prototype array uses Hall sensors to track the position of a magnetic target, attached to the structure, by sensing magnetic field variations caused by motion. A properly configured array will allow motion to be accurately determined without physically touching, and thereby altering, the dynamics of the system. A prototype sensor array developed by undergraduate students at Oklahoma Christian University is presented. This prototype array is currently only a bench tool for experimentation, but provides proof-of-concept for eventual implementation in submerged service. Preliminary results for the constructed array are discussed.
II. Non-contact Sensor Array Theory and Calibration
The proposed array consists of three Hall sensors arranged in a triangular pattern around a moving structure equipped with a small magnetic target, as shown in Figure 1. The prototype array discussed in this report will be a bench-top adaptation of this concept. The motion of the structure is determined within the plane defined by the sensor array by triangulating the location of the target using the Hall sensor signals. The Hall sensors (named for their use of the effect discovered in 1879 by Edwin Hall) produce a voltage proportional to the perpendicular magnetic flux striking the element 3. The magnetic field strength is related to the separation distance between the sensor and the magnetic target. Melexis Hall elements (Digi-Key Part # MLX90215LVA-LC03-ND) were used in constructing the prototype array.
Proceedings of the 2003 American Society for Engineering Education Annual Conference & Exposition Copyright © 2003, American Society for Engineering Education
Collins, H., & Newberry, B., & Lockwood, I. (2003, June), An Undergraduate Research Effort Into Non Contact Motion Tracking Paper presented at 2003 Annual Conference, Nashville, Tennessee. https://peer.asee.org/12031
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