The Study Of The Metallographic Sample-Cutting Machine' Control System

The Metallographic Sample Cutting Machine is a kind of metallographic equipments, which is mainly used to cut off sample from test material. It is widely used in metallurgical and mechanical manufacturing industry. At the present time, its research and manufacture in domestic lag behind that of some foreign nation. There has nessesity to research and enhance the domestic develop level. It aims to designing a control system, that can monitor the cutting process, which make the abrasion wheel avoid blocking or cracking, can make the sample surface has no over-heated area, has a smooth surface, which has suitability for the next operation梡olishing. Another goal is change the operate interface, which can make the machine more easy to use.The tool chain under General Public License is used to creat a practical develop platform. After analysis on the cutting process, the scheme is offered. By monitoring the rotation speed of abrasion wheel, the quality of cut-off samle surface is controlled in expected range.Photoelectric sensor is used in measuring the rotation speed of abrasion wheel to obtain dimension of circumferential abrasive force indirectly. PID control algorithm is used and its parameter is adjusted according the change of hardness and contact area of the cutting material. Embedded Linux develop kit is choosed and power driver circuit and some interface is designed. The software is write by C programming language, which include two parts: the real time interrupt procedure, which monitor the rotation speed, pressed key; and the main program, which adjust the control parameter, process the command of corresponding key, display the cut information and so on.According to the experiment, the designed PID control system has a less overregulate. Its static control accuracy is equal to constant PID control, its dynamic control accuracy exceed the constant PID control. The designed system make the abrasive load is more stable. Problems are settled that the feed speed is difficult tochoose and abrasion wheel is blocked or cracked and the sample is sometimes overheated. The design is proved feasible.Applying embedded Linux develop technology in metallographic equipments research first time. It make the develop put more energy on the applying implementation, avoiding low level repetitive develop work.This design is more advanced on technique and more reusable in develop engineering.