Development Of Measurement And Control System Of Undercutter For Pulling-motor Commutator

Undercutter is a device used to maintain commutator of pulling-motor. Its function is under cutting the mica-slots of commutator. Manual processing makes traditional mechanical undercutter precision-poor, inefficient and labour-intensive.A sophisticated measurement and control system of undercutter for pulling-motor commutator is developed in this thesis. Mechanical-transmission technology, AC-servo control technology, numerical control technology and sensor technology are used in this system. It achieves the automation of under cutting, and enhances the accuracy and efficiency of processing. This thesis includes:Firstly the transmission structure and processing principles of undercutter are discussed. And the measurement and control system structure of undercutter is introduced.The measurement system is mainly composed of laser contrast scanner and incremental code device. Through laser contrast scanner's identification on mica-slot and code device to record the angular displacement of commutator, the commutator's surface contour information is effectively acquired. Meanwhile, the quadruple and filter processing technology of the angular displacement signal ensure the high precision of measurement. Eventually, the relative position between mica-slot's center line and cutter is gotten.The design of external circuit and development of system software are simplified by making NC device as control platform of undercutter. And this method has shortened the development cycle and improved system reliability.A protection device to prevent mistaken processing is designed after discussing the sources of system errors and their impact on the processing precision. By studying the processing technic of undercutter, continuous processing and discontinuous processing are discussed. Experimental studies have showed that discontinuous processing can reduce the system accumulating errors, and ensure the high processing precision.Finally, the experimental data of actual processing are analysed , and a number of outstanding issues are discussed, forming the objects for future work.