Study And Development Of Laser-alignment Metrical System

The theory of laser-alignment is presented, then a metrical system as an application is developed and detailed in the dissertation. Power-transmitting through shafts is one of the most important methods of mechanical transmission, for which the two coupled shafts'centerlines must be aligned, that is, their coaxial error should be controlled within a permissible tolerance level. Otherwise, wastage will increase, for the worse, bearing, axes, connectors and other parts will be damaged. Therefore, it is essential for coaxial shifts to be measured, especially when rotational machinery are installed or manufactured. The usual metrical way is to use a dial indicators fixed on the shifts, but it proves to be a very hard work requiring rich experience for the operators as well as less accuracy, and it is not available for the long-distance measurement. Because of laser's good linear characteristic of direction, these problems will be well solved with the aid of laser.In order to satisfy the need of the productive practice, laser-alignment theory combined with the technique of photoelectric detect, communication and electronic are applied for a more convenient and reliable metrical system. A laser-alignment instrument is then developed, and has passed the experiment. In this system, VC++ 6.0 and KeilC51 are respectively used for developing the software and MCU, and serial port is for data transmission.Coaxial error between coupled shafts is analyzed for parallel off-set and angular misalignment, which can be respectively measured through the facula's offset on the plate of PSD, the accuracy of the system is assured by laser's good linear characteristic of direction and the accuracy of PSD. In the dissertation, measurement model, developing scheme and other functional parts are amply analyzed and discussed. The main studies are as follows:1. Analyze the main theories of laser-alignment, and build a new, practical metrical system;2. Analyze the measurement model, deduct the formula and realize the arithmetic of alignment theory;3. Develop the program of interface, arithmetic, serial port communication , data acquisition and database operations; 4. Design and develop the whole circuit on Protel99se, including the principle chart and PCB plate;5. Program drivers on KeilC51 and do the emulating experiments on WAVE;6. Debug ,analyze and test the upper program, drivers and circuit together;7. Analyze the systemic error;8. Debug the whole system and analyze the result then draw a conclusion from the result, give a prospect.This laser-alignment measurement system can obtain the automatic data- acquisition and processing as well as a friendly interface, which make the installation and adjustment work easily done. As the experimental result shows, the laser-alignment instrument can reach a accuracy of 0.001mm, still is repeatable and reliable; use of the system can greatly reduce the product efficiency and increase measurement accuracy.