Abstract: Aiming at the problem of uneven distribution of output pulse by the fine interpolation in the numerical control system, experimental study on the operation mechanism、hardware structure and software algorithm of the fine interpolator were summarized, the traditional solution of the fine interpolator and the reason about uneven distribution of output pulse were comparatively analyzed. A method of pulse uniformization algorithm based on the control law accelerator (CLA) module of synchronous digital signal processor (DSP) was proposed. A fine interpolator that could output distributed pulse evenly was constructed based on the hardware architecture with DSP and CLA in same clock signal, data bus and instruction, the running mode of processing task in parallel with running program in CLA by hardware trigger and the improved algorithm of double pulse period interpolation. A method was presented to test the pulse uniformization algorithm by hardware platform with TMS320F28377S and its online debugging function. The experimental results indicate that the time of output pulse occupy 100% of loop scheduling period in the CNC system by the design, and the pulse period can be as short as 2 μs, achieve the uniformization of distribution about output pulse.
Key words: digital signal processor (DSP); control law accelerator (CLA); pulse uniformization algorithm; fine interpolation