Study On Key Control Technologies Of NC Grinding Machine Of Radome

Radome, as the important component in communication and radar system, is one of the key parts of missile. The machining precision of radome directly affects the control and guide performance of the weapon. Generally speaking the semi-finished radome can't meet the requirement for electromagnetic properties. The NC grinding machine of radome is used to grind the inner surface of radome to alter the geometric thickness after precisely measuring it to get the machining base face, so that the electric thickness can be compensated to satisfy the electromagnetic requirement of radome.In this paper, according to the double function demand of the NC grinding machining for both precision measurement and precision grinding, the key control technologies of integrative measuring and grinding have been studied and a special computer control system is developed. The control system is an open architecture system comprising of an Industrial Personal Computer (IPC) and a Programmable Multi-Axis Controller (PMAC), having friendly man-machine interactive control panel, with a compound cascade control strategy integrate full-close loop and half-close loop and prefect electromagnetic compatibility. PMAC, as the system motion control center, sends back the working information of the machine to IPC when it is doing movement control, and IPC does works assigning and also system monitoring according to the information. PMAC and IPC cooperate together to accomplish the work in measuring and grinding.Radome's inner surface measurement belongs to the category of free-form surface measurement. After making analysis about the characteristic of the radome which is rigid and complicated rotary object and comparing various methods and moving tracks, an efficient measuring technique, which uses triggered-probe dynamically scan along a series of generatrices on the radome's inner surface, is adopted to get the geometric shape of base face in grinding. The sampling discrete points are gathered by using the special position capturing function of PMAC and laid out after pretreatment.Basing on structure and object-oriented method, the software system is analyzed and developed. The software system includes programs in PMAC and man-machine interface programs in IPC. The programs in PMAC main realize real time control, variable initializing and decoding of the machining code. The logic and I/O control of the system are done by PLC programs which are also in PMAC. The man-machine interface programs take charge resources and programs distribution and also the management of the system. There are manymodules in MMI programs, and they accomplish their functions, such as parameters setting, grinding etc, through calling functions in PCOMM32 PRO library.In order to reducee the errors brought out from the measuring and grinding works finished in one machine, a calibrating device is designed and the principle and the calibrating process are introduced. At end of the paper a software compensating method is brought to make sure the machine tool satisfies the position accuracy.The key technologies studied in the paper have been applied in the equipments in two aeronautical institutes in China.