For most rigid mechanisms, the standard PID loop parameters are all that are required to achieve good motion performance. For some high performance systems, the acceleration and velocity feedforward can further improve performance by providing additional torque early on to get the axes quickly moving. However, if the mechanism has resonance's due to flexing in the mechanical structure or elasticity in the drive train, the following optional tuning parameters can be of assistance as you perform Setup 2E to tune the position loop.
| Setup 3-Tuning: Tuning parameters for resonance's | ||
|---|---|---|
| Function | Action / DataID's | See Also |
| S-curve acceleration softening | To avoid exciting resonance's, specify long s-curve acceleration and deceleration ramp times. Increasing the ramp times will increase the total motion time, but by gradually ramping up and down the acceleration, you avoid "hammering" the system. Try a ramp time of 0.05 to 0.5 sec. To set the default ramp times, alter "Default max accel ramp time in sec" (2712) and "Default max decel ramp time in sec" (2713). |
(Web) ... > Joint/Cartesian control > Dynamic parameters |
| Feed forward softening | Similar to the effect of s-curves, the "Feedforward SPR filter pole, Hz" (10328) will soften the hammering effect of any feedforward compensation. |
(Web) ... > Servo parameters > Compensator |
| Output torque filtering |
To avoid having the torque output of the servo excite a resonance in the mechanism, a notch filter at the frequency of the resonance can be set by using the "Torque output filter pole, Hz" (10329) and the "Torque output filter damping ratio" (10330). |
|