Research On Wheelset Dimension Measurement Technology Based On Multi-line Structured Ligh

Wheelset is an important part of the running part of rail vehicle.It carries the weight of the train and has contact friction with the steel rail,so its size is constantly worn.In order to ensure the safe operation of the train,the wheelset size parameters need to be measured.Therefore,the research on reliable on-line detection method of wheelset size is of great significance to ensure the safe operation of subway.Based on multi line structured light measurement technology,this paper designs an on-line wheelset size detection system,and studies the image processing and three-dimensional measurement algorithms involved in the measurement process.The main work is as follows:(1)The principle and measurement model of multi-line structured light measurement technology are studied.Based on multi line structured light measurement technology,a wheelset size measurement system is designed,and the overall design of the system is given.(2)For complex multi-line structured light images,the stripes of different light planes in the image are matched and segmented using filtering,binarization,blob analysis and mask operations.For light stripe centerline extraction,an improved Steger centerline extraction algorithm based on skeleton pre-extraction is studied.Compared with the Steger algorithm,it avoids false extraction and improves the extraction speed by 2.3 times.(3)Wheel structure and the point cloud obtained from the measurement model characteristics were analyzed,and the algorithm of wheelset dimension measurement was studied.For the key lateral surface fitting,an improved RANSAC algorithm based on grouping sampling and verification is studied to improve the accuracy and speed of plane fitting.For the extraction of normal section outline,a method based on auxiliary plane is given in combination with wheel structure characteristics.The parameters of wheelset are obtained by using space plane circle fitting method and local curve fitting method.(4)Based on the system design,an experimental platform is set up,the measurement module is calibrated,and a multi-line structure light measurement model is built.The point cloud of wheelset is obtained from the measurement model and image processing algorithm,and then the 3-D measurement algorithm is used to calculate the wheelset size parameters.The feasibility of the algorithm is verified by laboratory and field vehicle passing tests.