Study and Realization of Hardware Precision Interpolation Based on CPLD Motion Control System

Aiming at the problem of the relatively low accuracy and speed of NC machine´s feed motion derived from the present pulse incremental interpolation algorithm and the digital sampling interpolation which is only suitable for the closed loop control system, a high-speed digital signal processor(DSP) has been raised for the realization of the rough interpolation of data sampling software; and a complex programmable logic device(CPLD) is to be used for the realization of the precision interpolation of data sampling hardware. Through the analyses of the operating principles of CPLD hardware interpolator, some key devices such as digital differential analyzer(DDA), interpolation algorithm controller, mode controller, quadruple frequency phase discrimination controller and so on have been designed. Through the analyses of waveform simulation, it has been proved that the method is applicable to the open looped NC system for stepping motor and pulse type full digital AC servo system and retains certain practical value for improving the performance indices of systems.