Rail Wear Precison Profilometer Based On DSP

The friction force which is generated when the train traveling on the rail makes the train traction, braking and guidance coming true. Meanwhile, it also causes the rail surface changes, it is bad to the wheel/rail dynamic performance. Therefore, measuring the rail head shape is the base work to the railway safety and economical operation. The purpose of this paper is to invent an instrument to increase the rail head's measuring rang and improve the abrasion accuracy. It includes the following jobs:Firstly, Based on the principle of measuring profiles with planar articulated five-bar mechanism and the standard of the rail abrasion calculation, the rail head's measurement model and the inverse kinematics model have been established. After the parameters of five-bar mechanism are simulated for optimization, a protable rail profilometer with double probe is investigated and designed, which is able to measure the whole rail's head and its jaw for the 50kg,60kg,75kg rail.Secondly, to improve the precision of the instrument, an acquisition system based on TMS320F2812 DSP has been designed, including power circuit, DSP minimal system, data collection interface circuit, data sending circuit, etc. And then according the feature of the rail head, data acquisition and processing have been researched. Data acquisition and sending software for DSP is compiled under the environment of the CCS3.1. Data processing software for PDA is to get the rail head curved shape, and then to calculate the abrasion values after the curved aligned to the standard curve.Finally, the calibration method has been designed to eliminate system error and improve measurement accuracy. Image instrument is used to calibrate the five-bar mechanism parameters and the encoder initial position angle.The model machine testing shows:Because of the powerful signal acquisition and processing ability, DSP2812 made the encoder pulse data acquisition and calculation easy and intelligently; The profilometer can measure the whole rail's head and its jaw; And, after using the curve digital alignment, the Vertical and Lateral wear abrasion of the rail head have been calculated accurately and conveniently.