Research on Radial Double Velocity Measurement Method of Laser Tracker

Abstract

For the dynamic problem that the low-speed sliding table is unable to meet the radial measuring speed of the laser tracker, this paper takes the sliding table of the indoor large-length standard device as the moving object to double the measuring distance by adding a pyramid prism, thereby doubling the radial speed of the laser tracker. In this paper, the measurement data are analyzed through equal interval measurement experiments, equal sampling frequency experiments and repeatability measurement experiments using a pyramid prism to obtain the following conclusions, respectively: Firstly, the stability of the actual interval of the laser tracker is optimal when the rated speed of the sliding table is 50 mm/s. When the pyramid prism is not used, the minimum standard deviation obtained by the laser tracker at a sampling interval of 5 mm is 0.0158 mm. Secondly, during the equal sampling frequency measurement, the stability of the laser interferometer is better than that of the laser tracker when the pyramid prism is not used. With two instruments at a sampling frequency of 10 Hz, the standard deviations of the local velocity of the laser interferometer are 0.1466 mm/s, 0.0693 mm/s and 0.1106 mm/s, respectively. The standard deviations of the laser tracker are 0.1582 mm/s, 0.1033 mm/s and 0.2008 mm/s, respectively. The same conclusion is obtained at a sampling frequency of 20 Hz. The stability of the laser tracker is better than that of the laser interferometer when the pyramid prism is used. Thirdly, the stability and reliability of the local velocity of the laser tracker are better than that of the laser interferometer. For example, at 10 Hz, the standard deviations of the local velocity of the laser tracker are 0.2745 mm/s and 0.2097 mm/s, respectively, and the repeatability of the local velocity is 0.9140 mm/s. The standard deviations of the local velocity of the interferometer are 0.6141 mm/s and 0.6368 mm/s, respectively, and the repeatability of the local velocity is 1.4886 mm/s. And the local velocity of the two measuring instruments is more reliable and stable at a low frequency (10 Hz). This experimental scheme provides a way to measure the high speed of a laser tracker using a sliding table at low speed.