The application of yaw sensor for measuring carriage system
Laser interferometers have generally been used for the angular measurement of measuring tape calibration systems. Yaw error measurements using a yaw sensor have been carried out to determine the characteristics of yaw errors and analyze the behaviors of the structural guide. The yaw sensor technique is identical to the error compensation used in a measuring tape calibration, and also has some special parameters. However, the yaw error observation period is very short, but it is sufficiently accurate for a carriage yaw sensor. This paper presents the yaw sensor innovation for the measuring carriage application that would be compensated by using yaw error is approximately minimized to 65 arcsec and its repeatability is less than 30arcsec.
The modification of yaw sensor for length standard calibration system
Yaw error measurements using a yaw sensor have been carried out to determine the characteristics of yaw errors and analyze the behaviors of the structural guide. The modification of yaw sensor design is necessary to improve the yaw error measurement. The contactless of a magnetic levitation technique that is supported a load of magnetic bearing. It is more suitable for reduction of yaw measurement error. This paper presents the new design of yaw sensor for the application that would be improved both the measurement error and repeatability. Those are measurement error and repeatability approximately minimized to 36 arcsec and less than 15 arcsec respectively, with the measurement uncertainty is 28.5 arcsec, at the confident level 95%.
A 50 m laser interferometer for automatic calibration of surveying tapes using wireless communication
A 50 m linear measuring interferometer, consisting of a precision laser interferometer, a 51 m long guide rail, a moving carriage, an optical microscope with a CCD camera and an image processor, is described here. The system is designed for the automatic calibration of surveying tapes. The carriage can move up to 50 m along the guide rail. The dc servo motor, which is fixed on the carriage, drives the carriage and its speed is controlled by a computer through wireless communication. The CCD camera captures the image of tape lines through the microscope fixed on the stage, and the image is wireless transferred to the image processor installed in the computer. The image processor calculates the deviation between the center of the line and the field-of-view of the CCD camera, and the laser interferometer measures the displacement of the carriage simultaneously. Finally, the intervals between lines are determined using the deviation and the reading of the laser interferometer. The calibration process is performed automatically after the installation of the tape. The estimated expanded uncertainty of the steel tape measurement is at the confidence level of approximately 95%.