PID Tuning COMDEF

A common principle in motion-control is that axes are tuned with a balance of speed and precision. As maximum speed increases, motion precision will drop. As maximum speed decreases, the motion precision can be increased without shaking or other adverse side effects. This is not unique to any one control system. It is a universal principle with all motion-controlled systems - and is taken into account when the machines are tuned.

For a bend-arm axis, push-bend arm motion can move very slowly - a fact that can be used to tune the axis in that condition for extreme high-precision without creating problems. Draw-bending arm motion needs to be faster, so the extra speed is traded for lower-precision in the tuning.

CNC Bender takes advantage of this principle for the different bend modes available. It examines the bending mode - either push-bend or draw-bend, then selects which PID command is inserted in the processlist.

Note that when we apply the term "lower-precision" to draw-bending, our systems are often many times more accurate than many competing systems. (It can be proved.) So the term "low" is relative to our system alone. "High-precision" means VERY high precision.

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