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Jan
06

Review of Deminar #11 – Feedforward Control -Timing is Everything

You can have the best feedforward measurement and accurate feedforward gain and still do more harm than good with feedforward control. If the feedforward correction does not arrive at the same time at the same place in the process as the disturbance, an irregular, oscillatory, and confusing response can occur. If the feedforward signal arrives too soon, there is inverse response. If the feedforward signal arrives too late, a second disturbance is created. A wireless measurement can help prevent the inverse response and second disturbance if the elapsed time of the wireless is reset upon activation of the feedforward and the default update rate is longer than the time to steady state. However, the additional delay of the wireless update rate could cause instability unless the traditional PID is detuned. An enhanced PID for wireless (PIDPlus) will prevent the instability without retuning regardless of how much the default update rate is increased to extend wireless battery life or to ride out feedforward timing errors.

If you want to view the screencast click on the picture.

 How to Setup and Adjust the Dynamic Compensation of Feedforward Signals - Greg McMillan Deminar

If you want to view the PowerPoint slides: How to Setup and Adjust the Dynamic Compensation of Feedforward Signals