Elevator Traction Wheel Rope Groove Wear Detection System Based On Monocular Vision

In recent years,the popularity of elevators in high-rise residential quarters,office and commercial buildings has been increased year by year,and the safety of elevators has gradually become a focus of public concern.Traction wheel is one of the important components of the traction machine in the elevator power system,and its reliability is very important for the safe and stable operation of the elevator.During the use of a traction elevator,the traction sheave grooves are subject to wear due to constant contact friction with the wire rope.Once the amount of wear of the rope groove exceeds the standard,it may cause the steel rope to slip and a safety accident.At present,the measurement of the amount of traction wheel rope groove wear in China was still limited to the traditional manual feeler measurement method,which has low accuracy and lacks traceable measurement data.This dissertation used a non-contact monocular vision measurement method,which not only can make up for the shortcomings of manual measurement,but also avoid the problems that the binocular stereo vision method is difficult to install in a small space and the dual camera is difficult to match due to the lack of public field of view The field of wheel wear detection has broad application prospects.In this dissertation,based on the principle of monocular vision,the detection of the amount of rope groove abrasion of traction elevator with semi-circular grooved traction sheave was studied.The measurement system hardware platform used a 5 million pixels,pixel size 2.2?m×2.2?m CMOS industrial camera and supporting light source.The industrial camera was fixed on the inner side of the wire rope through a jig and took an image of the contact gap between the wire rope and the traction sheave rope groove.The computer triggered the camera to collect image information through the control module,and the industrial camera transmitted the image to the computer through the Gigabit network cable for image processing.The measurement software was based on monocular vision technology,contour matching and other algorithms to achieve the target gap positioning.The measured value was compensated for the bottom of the rope groove to realize the real-time measurement of the amount of wear and sink of the elevator traction wheel.The camera's pinhole imaging model was first established and analyzed,and the calibration method for a single camera was studied in the dissertation.A 12 × 9 checkerboard calibration board was used to achieve the calibration of the camera system.Then,the target contour matching and edge fitting algorithms were analyzed and the real-time performance of the algorithm was verified.The measurement accuracy of the system was determined through a comparative measurement experiment with a digital vernier caliper with an accuracy of ± 0.02 mm and a range of 150 mm.The elevator machine room simulation experiment platform was built in the laboratory and static testing and performance verification were carried out.The experimental results are showed that the absolute measurement error of this system at the object distance of 300 mm is less than ± 0.1mm,and the average time of the algorithm is about 5s,which meets the measurement accuracy and real-time requirements of the traction sheave groove detection system.