Research And Development Of NC Puncher System Based On Embedded Technology

Some embedded microchip such as ARM, DSP, MIPS usually adopt reduced instruction set computing(RISC) technology with very fast execution cycle, strong real time ability, various source on chip and on-chip floating-point units(FPU) with single-precision and/or double-precision computations, which make them fit for the Numeric Control system. Besides, better means and testing platforms, and widely used real time operation system(RTOS) providing MCU development with good platform of task management and bottom drive, both guarantees the steady and convenient development and management of apply software.Based on the research and analysis of the stage and trend of NC machine domestic and abroad, and open-structure embedded NC technology theory, and following the discussion on the problems introduced from the system structure of current computer numerical control (CNC), such as the lack of tailorability, insufficient utilization of resources and complexity of interconnections based upon parallel interfaces etc., this paper presents and design an embedded-based numerical NC systems of puncher and describes the structure design in hardware and software.The hardware system adopts ARM+DSP as the main control platform. A 32-bit ARM microprocessor is employed as the MCU of the NC operation and management module, externally a SDRAM, a NorFlash and a NandFlash are added as extension memories. An RTL8019AS Ethernet interface is added to the module, and SL811HST is added as the USB controller to facilitate the transfer of NC code file. A DSP microprocessor is utilized as the MPU of machine control module, which connected to the puncher through I/O module and motor servo, fulfilling the motion control task.The software system adoptsμC/OS-II real-time embedded operating system, light weight TCP/IP protocol IwIP and FAT16 file system to construct the basic software running environment. Considering the real time ability and communication resource of ARM and DSP, we designed a communication protocol base on UART. The operation and management module realized basic human machine interface, management of the NC machining code files, edit and explanation of the NC machining code files, also, we realized the management of the NC machining code files in mobile disks by studying USB protocol and SL811HST drive, and it has network interface as well. The machine control module realized interpolation, intermittent compensation feed control and other motion control by calling relevant function modules.The embedded-based NC system of puncher overcome defects of current NC system, have the advantages of wide usage, high reliability, plug and play, tailorability and high performance-cost ratio, which is accord with the development of open structure NC system.