The Design Of The Automatic Welding Quality Inspection Equipment For Rails Welding Base-the Study Of Straightness & Flatness Detection Module For Rail Welded Joints

The unparalleled development of our country’s high-speed railway has increased our transportation capacity greatly, improving the running speed of the trains is still an essential direction of the present railway development. As one weak area of the track structure, the precisely control of the welded joints’ straightness and flatness is the significant assurance of the trains’safety, the necessary precondition of the railway’s further development also.The article introduced the mechanical frame of the stationary equipment of the rail welded joints’quality detection, designed straightness&flatness detection model. Described the detecting process and measurement condition of the straightness&flatness detecting model.The thesis has studied the algorithm principle of the stationary and the portable measurement system and the methods of the "two-datum" curve’s drawing, deduced the conclusion that the "two-datum" curve does not correspond to the real straightness and flatness of the welded joint. Firstly proposed the "one-datum" curve, which can describe the objective straightness and flatness of a welded joint precisely. Discovered the deviation between the "two-datum" curve and the real straightness and flatness of a welded joint has a positive correlation to the vector deviation between the two detecting endpoints of the detected rail. Gives the operation formula that can switch a "two-datum" curve into the rail’s real straightness and flatness curve, detailed reveals the difference between the two types of the curve under different vector deviation between the two detecting points.According to the principle of the "one-datum" curve’s drawing, the arch amount or concave-convex amount of the left side equals to which of the right side only when the vector deviation between the two detecting endpoints is 0. Geometric analysis has been applied to the measuring method from the Railway Industry Standard TB/T 1632 which using the lm straight ruler, revealed an issue that the unequal arch amount and concave-convex amount of the two sides had been overlooked. In this situation, the precisely control of the straightness cannot be guaranteed. A reliable way to control of the straightness precisely and a reasonable reference line drawing method is proposed.Meanwhile, the thesis programmed a software which can estimate the flatness qualification of a data and highlight the unqualified point when finding one. The data base of the software can import the straightness and flatness data so that the massive data can be managed and checked conveniently. A package of monitor and upload software also be programmed so that the concerned folder can be monitored and new data can be uploaded to the PC or sever with the IP which is appointed before.At the same time, a portable detector is designed. The detector using the motor and the synchro-wheels to drive the eddy current sensor so that the sensor’s precisely horizontal move can be achieved under the direction of the high precision guide. The position block is designed elaborately so that the detector can detect the running and directing surface of different type of the rails by change the orientation between the block and the beam.Nevertheless, the thesis programmed a Labview data acquisition project which based on the PCI Data Acquisition Card so that the portable detector can show the curve of the detected one-meter-rail. After designed a calibrate ruler, the detector was calibrated and the algorithm was corrected. Comparing the curves which drawn by the experimental detector,SEC-RC detector and RECTIRAIL DL2 detector, proposed the conclusion that the designed experimental detector can describe the straightness and flatness of a one-meter-rail with the curve precisely.