Research of NC Program Processor in Embedded Control System

NC program processor is an important module in Computer Numerical Control (CNC) system. NC program processor is divided into interpreter and look-ahead function. In the paper, the macro variable computation, the geometric transformation and the look-ahead pre-interpolation which is widely adopted in machining small-line blocks are introduced for their importance in modern CNC system. The former two works are executed in the interpreter, and the last one is performed in look-ahead pre-interpolation function. A method for five formats of computing macro variable is proposed as well as the proportion and rotation transformation in the interpreter. Then, four conditions including angle constraint between two NC blocks, chord constraint rule, length of the small-line and monotone rule are also discussed. NC program processor is implemented in an embedded control system based ARM (advanced RISC machine), DSP (digital signal processor) and FPGA (field programmable gate array) processors. Experiments show the system is reliable.