Development of FPGA-based arithmetic module in CNC system

Many complex computational problems have to be overcome in the Computer Numerical Control (CNC) system, such as tool compensation calculation, contour interpolation, speed decomposition, position control and so on. If all the functions are accomplished by software, the corresponding execution time will affect the velocity of the CNC system. This paper has put forward a scheme of software hardening technique based on FPGA (Flied Programmable Gate Array), and developed an independent arithmetic calculating module for CNC system to improve the feed-rate of machine tool. VHSIC Hardware Description Language (VHDL) is adopted in Quartus II 9.0 development environment, based on FPGA chip of Altera company CYCLONE II series. Several algorithm operation processes relating to complex calculation are introduced in detail, such as addition, subtraction, multiplication and division operation of floating-point numbers. The simulation results prove that the proposed design methods of the arithmetic module are feasible and reasonable, which can also enhance the portability and applicability of floating-point calculating module in CNC system.