Study On The Realization Technology Of NC Interpolation Algorithm Based On DSP Processor

Interpolation module is the core of the numerical control system. Along with the development of the modern numerical control technology, the interpolation algorithm is maturing and diversifying step by step. From the angle of mathematic model, it can be divided into straight line interpolation, conic interpolation and so on. And from the angel of output format of interpolation calculation, it can be divided into reference pulse interpolation (or pulse increment interpolation) and data sampling interpolation. At present, parameter curve real-time interpolation is gradually becoming a research hotspot of numerical control interpolation technology. The NURBS curve is a widely used parameter curve in practice. And the NURBS curve interpolation has become one of the most important functions in the modern CNC system.As for the design of open numerical control machine tool system, the priority job at present is how to choose a proper hardware system to interpolation. So that the control system could become more stable, and the interpolation algorithm would become more reliable and quicker. Nowadays, some numerical control interpolations using monolithic processor as controlling chip can not operate speedy because of the structural restriction, and can not satisfy the speed require of numerical control interpolation. DSP (the digital signal processor)chip, because of its special hardware structure (the Harvard structure, the multi-bus technology, the pipeline command structure, the Hardware multiplier), has high arithmetic capability (the single instruction execution time of current mainstream DSP chip is 8 to 10 times quicker than that of the 16-bit monolithic processor, and the time needed to perform a MAC is 16 to 30 times quicker), and can well satisfy the speed and accuracy require of interpolation arithmetic. Base on the mainstream DSP processor-TMS320LF2407 A of the TI company, the thesis uses the algorithm of numerical control interpolation to carry out technique research. Mainly performs the following operations:1,The thesis deeply study its for the principle of numerical control technology and the algorithm of interpolation. Thorough of comprehend for the classification and develop present condition of the modern numerical control interpolation. It provides the basis for algorithm of the following selection and improvement.2,It deeply study its for the DSP processor. Comprehend structural principle of DSP and master its applied technique. And selects proper motor control TMSLF2407A as control processor chip.3,Base on TMS320LF2407A to select other outer circle chip,stepper motor and the driver of stepper motor .The thesis also constructs the hardware system and analyses capability of the system.4,The thesis deeply researches and study its for the numerical integration interpolation algorithm as the required accomplishment numerical control algorithm. At the same time, it also studies for NURBS interpolation method which widely used step by step at present.5,The thesis has designed software systems and divided module research. And it given out the program flow chart of DDA straight line and the arc interpolation. The thesis also writes interpolation source program and tries to design the program flow chart of NURBS interpolation.