The Research And Design Of Open Architecture CNC System Interpolation Based On SoftDMC

In recent years, with the design ideas of the open Architecture CNC system proposed and the rapid development of the PC technology, modern CNC system are developing towards the open Architecture system. The open Architecture CNC system, which has the advantages of flexible for it adopts modular design method, very suitable for modern manufacturing technology development.Firstly this paper analyzed the overall architecture of the CNC system. The original CNC system of our lab used software to implement all the CNC functions, which caused that the speed cannot be improved sufficiently because of the software implementation will take some time and the operating frequency of the processor is certain. Especially in the high-speed manufacturing occasions, the speed and efficiency of the all-software CNC system will be the manufacturing bottleneck. Thus, with the development of the large-scale programmable logic device FPGA technology, this paper presents a new concept SoftDMC motion controller, that is embedded a small DSP core in FPGA. On this basis, a portion of NC function (the CNC fine interpolation) implement on the hardware.At present, the common interpolation algorithm can be implement by hardware or software. In this paper, the two levels interpolation scheme of coarse and fine is used. The coarse interpolation based on velocity linking of small segment and velocity planning run on the RTLinux platform of the industrial control computer; The fine interpolation based on the cubic spline interpolation algorithm run on the SoftDMC platform of the Mesa5I20 motion control card. This can take full advantage of hardware and software resources, which diminishes the error caused by the interpolation algorithm for approximating the outline of trajectory, helps to improve the output precision interpolation calculation and contribute to release high-speed and high- precision manufacturing.