The design of a laser-based digital displacement/deflection measurement system of a remote object and its calibration

摘要

We describe in this paper a laser-based digital displacement measuring system, which can detect displacement or deflection of an object in a long distance. It has the advantages of nor-contact, high resolution, fast response, and more importantly being remote. In order to achieve a remote measurement, the laser beam is first collimated, and directed to the detector array, which is attached to the remote object to be measured. The relative movement between the laser source and the detector will provide a measure to the displacement or deflection of the object. This system has three major features compared with the common laser-based displacement measurement systems. The first one, remote wireless digital signal and data transmission has been used in this measurement system, which increases the stability and practicability of the system. The second one, a laser level instrument has been used as a laser source, which makes it much easier to direct the laser beam to the detector at a long distance. The last one, MCU and LED have also been investigated, which makes the system more convenient. The measurement effect is proved by experiment. The academic measuring distance of the system is 100m and it is calibrated at a distance of 20m in the lab. The measuring frequency of the system is 29Hz. The error of the system is between -0.07mm to 0.07mm and the standard error is less than 0.05mm. The standard error of the system at an immovable point in four hours is 0.0134mm. Due to its features, perspective of its appreciation should be wide.