Model based compensation of systematic errors in an inductive gap measurement method
(English)Article in journal (Other academic) Submitted
This paper presents an improvement to a recently presented inductive gap measurement method, using a model to reduce systematic errors. Gap measurement is important in laser keyhole welding, where the laser beam and the resulting weld seam are very narrow, requiring high precision in alignment and gap preparation. The previously reported method for gap measurement uses one inductive coil on each side of the gap, each measuring distance to the gap and lift off above a plate, to estimate the position, width and alignment of the gap in a square butt joint. The method can detect zero width gap and shows position error less than 0.1 mm, but gap width and alignment measurement suffer from systematic errors. The improvement is based on a model that is designed to describe these systematic errors as functions of the gap dimensions. The model relies on observations of experimental data, and is calibrated to a small set of measurements. Using the model with the initial estimate of the gap dimensions to compensate the coil measurements, an improved estimate of the gap dimensions can be calculated. The errors in the compensated results are within 0.1 mm except for gap width, which still suffers from the effect of combined gap width and misalignment.
Seam tracking, inductive, complex response, zero gap, laser beam welding, error compensation
Manufacturing, Surface and Joining Technology
Research subject Production Technology
IdentifiersURN: urn:nbn:se:hv:diva-10148OAI: oai:DiVA.org:hv-10148DiVA: diva2:1047298
Ingår i lic. uppsats2016-11-172016-11-172016-11-17Bibliographically approved