Study On The Embed CNC System Based On ARM MPU

This Paper study on the feasibility of CNC system hardware based on cheapness ARM core processor-LPC21XX series single-chip, and put forward interface circuit scheme of CNC system which marked out by research target based on make full use of the resource of LPC21XX series single-chip. These interface circuit scheme include interface circuit scheme of inner PLC, interface circuit scheme of hardware fine interpolation, interface circuit scheme of keyboard and LCD, and interface circuit scheme of memorizer. Etc.The Paper using twice interpolation method, established a work flat on which rough-interpolation was complete by software, fine interpolation was completed by hardware. It can realize 3-axis linkage, of course it can control the CNC machine, lettering machine, embroider machine, manipulator, etc. During the phase of rough-interpolation was realized through data sampling. The phase of fine interpolation was completed by Intel 8254's subharmonic component.For discussing convenience, the concept of "minimum Shot-axis frequency-divide coefficient" is put forward. Short-axis refers to the axis that has shortest feed distance in a interpolation course among all feed axis. It is corresponding to large frequency-divide coefficient. Frequency-divide coefficient of Short-axis determines the precision of interpolation, and vice versa. All above should be considered synthetically to determine the pulse-generator output frequency.In CNC settings, in order to avoid impact, asynchronization, over-travel, vibrate. Etc. We must practice the acceleration/deceleration control. When interpolation Trapezoidal acceleration/deceleration control uses short time in the same distance, as the distance, maximum velocity, acceleration, and deceleration are the same for both Trapezoidal Profile and S curve Profile. Of course S curve acceleration/deceleration control use more time. But the S curve acceleration/deceleration impact response is resolved well at the turning point.