We present a dispersive interferometry of optical frequency comb for simultaneous measuring absolute distance and angle. The reconfigured Michelson interferometer can emit two parallel measured beams and one reference beam. The three pulse beams interfere with each other, and the interference spectrum is sampled by a spectrometer. It is simultaneously modulated by the three optical path differences, which contains the information of absolute distance and angle and can be demodulated by a Fourier transform. By making an angle measurement comparison with a calibrated turntable, the proposed method shows that the obtained mutual agreement is better than 3 arcsec in the range of ±5°. The commercial interferometer and autocollimator are used to verify the feasibility of the proposed method for precision distance and angle measurement.

The workspace measurement and positioning system is a three-dimensional (3-D) coordinate system based on laser scanning, which is widely applied in large-scale metrology. As a core part ensuring measurement accuracy, the transmitter parameters’ calibration is the critical technique of the system. The present transmitter parameter calibration method relies on auxiliary measurement equipment, which is more error prone and less efficient. This paper will focus on the improvement of the transmitter parameters’ calibration by using a highly precise 3-D coordinate control network. Several calibration points with known coordinates are set in the workspace to establish the precise 3-D coordinate control network. After the new model of transmitter parameter calibration has been explained, both the calculation method for optimization and the production of the initial iteration value are given. As indicated by the results of the verifying experiment, the accuracy and efficiency of the transmitter calibration can be distinctly improved by using the proposed method. The experimental data show that the 3-D coordinate measurement error has obviously decreased from 0.3 to 0.15 mm as a merit of the proposed method.

Directed at the strong correlation among the input parameters and long measurement chain, which are difficult for uncertainty analysis with the guide of the expression of uncertainty in the measurement (GUM) method, a novel dynamic stereo vision measurement system based on the quaternion theory is presented to reduce the orthogonality restrictions of shafting manufacturing and application. According to the quaternion theory in the kinematic model of the cameras and the analytical solution of uncertainty with the GUM method, the complete, detailed, and continuous uncertainty results of the full-scale measurement space can be obtained. Firstly, one-dimensional turntables and rigid connections are utilized to form the motion cores and the automatic control carriers in the system. Secondly, the novel measurement model is used in the measurement process to shorten the calibration and measurement chains. Once the system based on the novel measurement model is set up, the analytical solution of uncertainty is utilized in the accuracy process. During the analysis process, the strong correlation among the extrinsic parameters is decoupled by introducing virtual circles and the measurement strategy with the GUM method. Through analyzing the relationship among the attitude angles, the major factors which influence the uncertainties in each axis and the final uncertainty are clarified. Moreover, the analytical continuous uncertainty maps for the uncertainties along each axis, combined standard uncertainty, and the expanded uncertainty are illustrated and the uncertainty variation tendency is declared. Finally, the analytical solution of uncertainty with the GUM method proposed in this paper predicts the uncertainty in the full-scale space and provides a new idea of the uncertainty analysis for the complicated combined measurement system.

Laser-tracking measurement systems (laser tracker) have been playing a critical role in large-scale 3D high-precision coordinate measurement. However, the existing visual guidance of laser trackers is still limited by the disadvantages of operator-dependence, small-angle view field, time-consuming laser-guided process. This paper presents an automatic guidance method for laser trackers based on the rotary-laser scanning angle measurement technology. In this method, a special target consisting of six photoelectric receivers and a retroreflector is integrated into the rotary-laser scanning transmitter’ coordinate systems. Real-time constraints calculated by the proposed method would provide the coordinates of the target in a laser tracker coordinates system for guidance. Finally, the experimental results verified the automatic re-establish of sightline can be realized in horizontal 360° angle field within tens of arc-seconds, and this method is robust against the fast movement of the target.

The fault diagnosis of dimensional variation plays an essential role in the production of an automotive body. However, it is difficult to identify faults based on small labeled sample data using traditional supervised learning methods. The present study proposed a novel feature extraction method named, semi-supervised complete kernel Fisher discriminant (SS-CKFDA), and a new fault diagnosis flow for automotive assembly was introduced based on this method. SS-CKFDA is a combination of traditional complete kernel Fisher discriminant (CKFDA) and semi-supervised learning. It adjusts the Fisher criterion with the data global structure extracted from large unlabeled samples. When the number of labeled samples is small, the global structure that exists in the measured data can effectively improve the extraction effects of the projected vector. The experimental results on Tennessee Eastman Process (TEP) data demonstrated that the proposed method can improve diagnostic performance, when compared to other Fisher discriminant algorithms. Finally, the experimental results on the optical coordinate data proves that the method can be applied in the automotive assembly process, and achieve a better performance.