Motorized Measurement of Deformation on Surface of Revolution With 2-D Laser Profiler

The 2-D laser profiler potentially provides an efficient way to measure the profile of a deformed surface of revolution. However, the application is constrained by its finite measurement range, as well as the accumulated errors during device installation, workpiece placement, and 3-D reconstruction. In this work, an integrated measurement system is designed with high-precision rotary table (HRT) and a motorized vertical stage (MVS), so that in situ scanning measurement is achieved by coordinated motion of the workpiece and the 2-D laser profiler. An extrinsic calibration method is proposed between the 2-D laser profiler and the HRT with fittings of a plane and a circle curve by the Leica absolute tracker (LAT), so that large tolerance of installation error is allowed for both MVS and HRT. Eventually, the point cloud of the workpiece with respect to the HRT is virtually relocated on the CAD model by the iterative closest point (ICP) algorithm with the kd-tree construction, so that the amount of deformation is correctly assessed even when the deformed workpiece is arbitrarily clamped by the three-jaw chuck. The experiment is conducted on the testbed for measuring the deformation of a wheel rim, which verifies the effectiveness of the developed system and the proposed method.