Zhang Guoxiong

An improved cat’s-eye retroreflector used in a laser tracking interferometer system

As an optical retroreflector used in a laser interferometer system, a cats eye is expected to provide high parallelism of the reflected beam, especially for large-range measurements. On the other hand, a cats eye should be light and portable for the convenience of operation in taking the actual measurement. To solve these problems, a new method for optimizing the parameters of a cats eye is proposed to obtain the least divergence angle of the reflected beam. Theoretical analysis and experiment show that the improved cats eye not only has smaller volume and less weight, but also greatly improves the parallelism of the reflected beam.

Online test system of large screw thread

A new method for automatically detecting the large screw thread is discussed by using the neotype gauge head of thread which includes TESA inductance type transducer and survey probe chosen according to the tooth-type of thread.The way of contact measurement is adopted on the basis of the synthetically measuring principle for thread.The functional diameter of thread is investigated and analyzed experimentally.Through spectrum analysis,the dynamic error is picked out while data of functional diameter of thread will be obtained.Because the measurement strength of the neotype gauge head is much smaller than that of the regular screw gauge so as to diminish the most measurement error resulted from the contact stress.Experimental results show that the neotype gauge head of thread can improve measuring accuracy and the measuring accuracy reaches l~tm after data processing.

Thread probe measuring angle calculation of flexible calibration

Large tubular serrated thread detection method uses a new type of threaded probe, the Cone anvil of the probe is selected by the thread teeth type. The angle between the axis of thread and cone is 60 °, the calibration device in this paper is designed to flexible to the angle of calibration, and the measuring range of flexible calibration for anvil is theoretical analyzed and calculated.

Application of particle filter in high accuracy geometry measurement

In order to enhance the adaptability of visual inspection systems to different environmental illuminations and backgrounds in projects, to eliminate the interference owing to various disturbances, such as the noises of inside circuits, the ideal model and the actual situation with the disturbances of noise of a gray transition region of a target edge was investigated and a new self-adaptive method for noise elimination and image segmentation based on a particle filter was proposed. First, the noise particle set of the pixels in the gray transition region of the target edge at the initial time was established, posterior probability density of noise particle was acquired through the recursive Bayesian estimation method, and disturbances on pixels of the gray transition region of the target edge was eliminated. Then, the iterate result of the precise edge position was estimated for the instability of the grey value of pixels in the gray transition region of the target edge. Finally, the geometrical parameters of the target concerned were solved with the computation of the data of the complete contour extracted. Using the method, the angle measurement accuracy is less than 0.0068 degrees, and the standard deviation is 0.00123; the diameter ratio measurement accuracy is less than 0.00057 degrees, and the standard deviation is 8.67215E-5. In conclusion, the proposed algorithm can quickly and precisely achieve the noise elimination and image segmentation.