Optical fiber method for measuring small plane flatness error

摘要

A non-contact flatness error of small plane measurement method based on reflective optical fiber displacement sensor is presented. Using the model of single optical fiber, the light from laser source is modulated by the modulator. The modulated light passes through a circulator to an optical switch to realize the Time Division Multiplex (TMD) of optical fiber sensing array. The reflective light passes through the circulator to a common detector and process circuit. This configuration avoids the problem of parameter disagreement of multi-processing circuits, improves the measurement efficiency and cuts down the cost. The intensity fluctuation of the reference light is adopted to rectify the effects of the power variation of laser source, so as to improve stability of the system. The experiment results show that the measurand flatness error is consistent with the measurement result of Three Coordinates Measuring Machine (CMM). The architecture of the system is simple that it can be used in flatness error measurement of mechanical parts of different shapes by changing the number and layout of the optical fiber sensing array flexibly.