Measuring System For Contact Wire Geometry Parameters

A new "Measuring System for Contact Wire Geometry Parameters" is designed in the thesis paper. Rotating laser is used to measure contact wire geometry parameters and digital signal processor is used to control the system and process data. High technologies nowadays are applied, for example: Laser ranging, digital signal processor, complex programmable logic device, analog-to-digital converter with high precision, stepper motor, power rechargeable battery pack of lithium ion.What is the contact wire, and its three important geometry parameters, height, stagger and wear, are explained in the first chapter. The catenary examining and repairing mode that Power Supply Segment of Chengdu Railway Bureau used is observed and learned. Contact wire geometry parameters measurements of inland and overseas are referred broadly. Portable system of contact wire geometry parameters measurements of inland now are analyzed and compared, for example, JJS laser catenary measurement, DJJ multifunction laser catenary measurement, TJC ultrasonic catenary measurement. Several contact wire wear measuring systems of overseas are introduced, like WIRE CHECK of Italy, SURCAT of France and contact wire wear measurement of Japan.System parameters and requests are brought forward in the second chapter. Then the operating principle of the system is described. The principle of laser ranging applying phase and pulse is given. The way of computing contact wire geometry parameters is analyzed in detail. Finally, measuring error is calculated by theoretic analyzing and practical application, and the superiority of the system is given.In the third chapter, popular digital signal processors of these days are compared, and TMS320F2812 chip made by Texas Instruments is confirmed to control system and process data. The inner configuration, hardware characters and main performance parameters of the chip are presented. The integrated development environment of software, CCS, is recommended simply.In the fourth chapter, each actual module of different functions is selected according to design request. SEED-DEC2812 board based on TMS320F2812 chip is chosen as the center of system and other modules are connected to the center board. And then, the function, main parameters and interface of each module are shown, the referred modules include SEED-DEC2812 board, Banner LT3NI laser ranging, AD7892 Analog-to- digital converter board, stepper motor and driver, inclinometer, liquid crystal display and power supply.In the fifth chapter, several experiments are done to prove the correctness and feasibility of the design. Five sub- experiments are presented: communications between central DSP board and computer, DSP controlling stepper motor achieving rotating laser, Laser ranging sensor calibrating, AD7892 sampling profile, DSP software compiling of contact wire geometry parameters. The process of experiments is described in detail. Many practicality photographs, data, and partial program are given. Finally, all the experiments are summarized and farther improved advices are given.AD7892 ADC board schematic diagram, main program of DSP, DSP28_Sci.h and DSP28_Sci.c source program are supplied in appendix.