FBG-based online monitoring for uncertain loading-induced deformation of heavy-duty gantry machine tool base

Abstract

An online monitoring approach for the uncertain loading-induced deformation of heavy-duty gantry machine tool base has been proposed by the combined use of Fiber Bragg Grating (FBG) sensors and a curvature-deformation algorithm. A placement strategy has been proposed to the deployment of these FBG sensors, ensuring to effectively sense the curvature. A cubic spline interpolation method has been applied to fully construct several continuous curvature functions. Deformation reconstruction principle based on these piecewise curvature functions has been elaborated and derived. FEM-based simulations for a prototyped base have been conducted to preliminary validate the effectiveness of the proposed approach. Experimental results further indicate that the maximum relative error of the reconstructed deformation values is decreased from 69.53% to 11% with an in-site calibration. The average of relative error with a value of less than 5.6% under different uncertain loadings, together with good consistency between the calculated deformation and detected values from the commercial sensors, have demonstrated the effectiveness and feasibility of the proposed approach. Several application experiments in a real gantry boring and milling machine tool base have been performed to further validate the feasibility of the proposed approach.