Evaluation of a multi-sensor horizontal dual arm Coordinate Measuring Machine for automotive dimensional inspection

Abstract

Multi-sensor coordinate measuring machines (CMM) have a potential performance advantage over existing CMM systems by offering the accuracy of a touch trigger probe with the speed of a laser scanner. Before these systems can be used, it is important that both random and systematic errors are evaluated within the context of its intended application. At present, the performance of a multisensor CMM, particularly of the laser scanner, has not been evaluated within an automotive environment. This study used a full-scale CNC machined physical representation of a sheet metal vehicle body to evaluate the measurement agreement and repeatability of critical surface points using a multi-sensor horizontal dual arm CMM. It was found that there were errors between CMM arms and with regard to part coordinate frame construction when using the different probing systems. However, the most significant effect upon measurement error was the spatial location of the surface feature. Therefore, for each feature on an automotive assembly, measurement agreement and repeatability has to be individually determined to access its acceptability for measurement with a laser scanner to improve CMM utilisation, or whether the accuracy of a touch trigger probe is required.

Calibration of laser beam direction for optical coordinate measuring system

“…1 are established. Through transformation among them, flexible disposition of merging data from multi view and orientations into a unified coordinate system can be achieved [19]. In order to acquire the 3D coordinates of the light spot and then transform them into the unified coordinate system O C -XYZ, which may help to merge together the measuring data, it needs to convert the output of the laser sensor to O C -XYZ according to the sequence:…”

Comparison of in-line and off-line measurement systems using a calibrated industry representative artefact for automotive dimensional inspection

“…The aim of this paper is, therefore, to investigate the measurement capabilities of three different measurement systems: (a) CMM touch-trigger probe, (b) CMM laser scanner (L100), and (c) laser radar (LR), using a fully industry representative and certified artefact, which includes standard features measured in the automotive sector. The majority of the research in this area often compared two similar measurement systems such as comparing off-line systems [8,31,34,43] or only use of the LR [11,12,14] .However, this study evaluate three different systems which are in high demand for automotive industry [33]. The CMM touch trigger probe is the benchmark off-line measurement with well-established determination of measurement capability and uncertainty.…”

A posture adjustment optimization method of the laser inspection device for large complex surface parts

“…The inspection device posture adjustment optimization of three-dimensional (3D) parts has been studied by some scholars. 16 Isheil et al 17 proposed an error correction procedure based on an experimental process which considered the orientation between the sensor and the surface, and the posture adjustment of laser inspection device is optimized to reduce the inspection errors. Derigent et al 18 presented a method to determine the 3D digitizing strategy for a mechanical part using a plane laser sensor, and a new approach based on the Minkowski operations is used to calculate the visibility of the different faces of the B-Rep model of the part; the minimum set of directions required to entirely digitize the part is computed to optimize the posture adjustment of laser inspection device.…”