Optical fibre sensor

Abstract

An optical fibre sensor 18a(b) which functions as a tactile sensor, e.g. for a manipulator, includes a plurality of shearing stress sensor sections 32, 34 and a perpendicular stress sensor section 36, each section including respective optical fibres 38, 44, 50 and a plurality of gratings 40, 46, 52 such as fibre Bragg gratings (FBGs), for reflecting light beams at particular wavelengths. The gratings are arranged in the optical fibres such that the sensor is responsive to shearing stress applied to the sensor along X- and Y-axis directions as well as to perpendicular stress applied along a Z-axis direction. Stress direction converting means such as elastic members (156, figure 17) for converting the direction of an applied stress may be mounted on the optical fibres.

Description

technical field [0001] The present invention relates to a fiber optic sensor for detecting stress using an optical fiber incorporating a plurality of gratings for reflecting light beams having specific wavelengths. Background technique [0002] In some manipulator applications, the manipulator grabs an object and performs some type of work on the object. At this point, if the manipulator applies excessive grasping force to the object, the object tends to be destroyed. Conversely, if the manipulator does not apply sufficient grasping force to the object, the object may fall from the manipulator. [0003] In order to prevent damage to the object or hold the object stably, attempts have been made in the prior art to combine a manipulator with a sensor to detect the grasped state of the object being grasped by the manipulator. One such sensor includes a tactile sensor for detecting vertical stress from the object as the gripping force of the manipulator, and shear stress from ...

AI Technical Summary

Problems solved by technology

[0009] However, even with the structure disclosed in Japanese Laid-Open Patent Application No. 2005-134199, if the object grasped by the manipulator has a different shape or touches the optical fiber at a different position, a different Stress distribution

Therefore, it is not easy to determine the precise magnitude of the applied stress, or in other words, to obtain a sufficiently high level of measurement accuracy

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