Straightness Perception Mechanism of Scraper Conveyor Based on the Three-Dimensional Curvature Sensing of FBG

In order to solve the key technical problem of accurate perception of the straightness of a scraper conveyor in intelligent mining of coal mines, a three-dimensional (3D) curvature sensor of fiber Bragg grating (FBG) is designed and developed based on the curvature sensing principle of FBG. The grating string embedded in the FBG curvature sensor is simulated under the radius of curvature of 100 m, 200 m, 300 m, 400 m and 500 m. The results show that the strain of the built-in FBG string is linearly related to the curvature at the bend of the FBG string. The simulation results are consistent with the theoretical results, which verifies the rationality of the sensor design. Based on the discrete curvature information obtained by the 3D curvature sensor of FBG, the curve reconstruction algorithm is derived by using the method of fitting recursion, and the bending shape fitting perception and curve reconstruction of the scraper conveyor is realized. A test platform for the three-dimensional bending of the scraper conveyor is set up. The measuring effect of perceived and actual shape at the straight and bending states of the scraper conveyor is verified. The test results show that the measured curve is basically the same as the perceptual curve in the three-dimensional bending configuration of the scraper conveyor, and the error of the direction of each coordinate axis is not more than ±15 mm, which can meet the requirements of the accuracy of detecting the straightness of the intelligent work.