Research On The Key Technology Of Embedded CNC Software Platform

As various kind of embedded processors and embedded real-time operating systems emerging, it is possible to construct ECNCs(Embedded CNC Systems). This thesis describes the architecture of ECNCs and introduces its designing method. Based on this architecture, two complete new schemes are presented and implemented. The second one, which employs the embedded-system technology on the cutting edge, replaces the microprocessors or microcontrollers based CNC control unit. This kind of ECNC has the advantage that it can be upgraded, expanded in comparison with traditional systems.This thesis presents a reference architecture for ECNCs. The architecture is partly derived from existing HNC(HuaZhong Numerical Control System)at National Institute of Numerical Control Center, which has the characteristics of openness, flexibility and maintainability. Two application schemes based on this ECNC architecture are designed, i.e., HNC hardware platform plus ETS embedded real-time operating system and Nios soft-core processor hardware platform plusμC/OS-II embedded real-time kernel. The second scheme uses the soft-core processor to design ECNC, which is a new attempt to construct CNC system into a SOPC(System On a Programmable Chip).The method to deal with tasks in ECNCs(containing task partition and task priority assignment, etc) is discussed and mainly focused on task scheduling. The tasks are divided into periodic tasks and non-periodic tasks by executing-time, and also divided into hard real-time tasks and soft real-time tasks by their importance. The scheduling method and communicating method between tasks are discussed after task partition and task priority assignment.The method of designing HMI(Human Machine Interface) and especially 3-D graphic rendering are introduced. The UML(Universal Modelling Language)is used to analyze the relations among the components of HMI. A new architecture is introduced to eliminate the redundant operations on invisible triangles. This architecture is also tested by a program which renders a graphic entity on ECNC software platform.Based on the theory presented above, the two application schemes are constructed. Several programs are written to test the function of the platforms. The results show that the two schemes can be realized and the ECNCs have the characteristics of real-time, robust, low-cost and low-power consumption compared with common CNCs.