Integrated calibration of a 3D attitude sensor in large-scale metrology

Yang Gao,Patrick Keogh,Jigui Zhu,Linghui Yang,Jody Muelaner,Jiarui Lin

doi:10.1088/1361-6501/aa7275

Yang Gao, Patrick Keogh + Show 4 more

Open Access

https://doi.org/10.1088/1361-6501/aa7275

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Abstract

A novel calibration method is presented for a multi-sensor fusion system in large-scale metrology, which improves the calibration efficiency and reliability. The attitude sensor is composed of a pinhole prism, a converging lens, an area-array camera and a biaxial inclinometer. A mathematical model is established to determine its 3D attitude relative to a cooperative total station by using two vector observations from the imaging system and the inclinometer. There are two areas of unknown parameters in the measurement model that should be calibrated: the intrinsic parameters of the imaging model, and the transformation matrix between the camera and the inclinometer. An integrated calibration method using a three-axis rotary table and a total station is proposed. A single mounting position of the attitude sensor on the rotary table is sufficient to solve for all parameters of the measurement model. A correction technique for the reference laser beam of the total station is also presented to remove the need for accurate positioning of the sensor on the rotary table. Experimental verification has proved the practicality and accuracy of this calibration method. Results show that the mean deviations of attitude angles using the proposed method are less than 0.01°.

Highlights

The problem of accurate attitude measurement for rigid body objects is important in large-scale equipment manufacturing and the engineering of several domains including aircraft and spacecraft, ships, tunnel boring machines, and cranes [1,2,3,4]
A novel calibration method is presented for a sensor fusion system in large-scale metrology, which improves the calibration efficiency and reliability
Motivated by the aforementioned studies, this paper proposes a novel calibration method for TS-attitude sensor in [18] which uses a three-axis rotary table and a total station as calibration tools to provide reference standard

Summary

Introduction

The problem of accurate attitude (orientation) measurement for rigid body objects is important in large-scale equipment manufacturing and the engineering of several domains including aircraft and spacecraft, ships, tunnel boring machines, and cranes [1,2,3,4]. Neither of them have a stable attitude accuracy better than 0.1°, besides, GNSS is not appropriate for use in indoor and underground environments, and electronic compasses may be influenced by local magnetic fields Another existing method is to use optical or vision based observations of targets located on an object [9,10,11]. The Leica T-Mac uses a motorized camera on the tracker station to track the multiple points on the T-Mac probe [12] It is a combination of laser tracking for position and PnP technique for orientation. The laser tracker based method has high accuracy, it has limited measurement range, is extremely costly and is not suitable for engineering applications in harsh environments. Concluding remarks and a brief overview of further work are presented

Principle of Measurement

Measurement Model The measurement model involves the following conventions:

Integrated Calibration Method

Experiments

Conclusions