Adaptive Amplitude, Offset and Phase Control for Waveforms


#1

Attached are example projects for adaptive amplitude control. Adaptive amplitude control is used for high-frequency repeating waveforms such as a sinusoid. The adaptive amplitude control changes the amplitude of the target signal (such as position of force), so that the actual amplitude reaches the desired amplitude.
Normal tuning can be very difficult for high-frequency waveforms, and the adaptive amplitude control makes it much easier. With adaptive amplitude control, a delay between the actual and target signals is expected. If you need the actual to follow the target exactly, adaptive amplitude will not work.

Attached are some examples:

  • Adaptive control of the amplitude and offset of a closed-loop sinusoidal wave, triangle wave, square wave, and trapezoid wave. The project includes user programs that generate a closed-loop sinusoidal, triangle, and square target profile and automatically adapt the target amplitude and offset such that the actual measured amplitude and offset match the requested amplitude and offset
  • Multi-axis adaptive control of amplitude, offset, and phase of a closed-loop sinusoidal wave. 4 axes. The project includes a user program that generate a closed-loop sinusoidal target profile and automatically adapts the target amplitude, offset and phase such that the actual measured amplitude and offset match the requested amplitude and offset.
  • Adaptive control of the amplitude and offset of a closed-loop sinusoidal wave for force.

This adaptive control is useful for test systems where the amplitude, offset, and possibly the phase are important, but there may be some change between each run, and it is not feasible to re-tune the system.

This method makes tuning the system very easy, if the only objective is to get the correct amplitude and offset. The position tuning itself doesn’t need to be tuned very well (just proportional gain is often enough), and the adaptive part will bring the offset and amplitude right on! You may need to adjust the two adaptive gains, but the default values of 1 may work quite well.

For the phase control, a positive phase is leading, and a negative phase is lagging. Typically, one axis will run at 0 phase, and the others will be lagging by specified amounts (negative phases).
Adaptive Closed-Loop Sine Wave Force.rmcproj (38 KB)
Adaptive Closed-Loop Sine Wave with Phase 150.rmcproj (86.3 KB)
Adaptive Closed-Loop Waveforms.rmcproj (107 KB)


min max values and adaptive control
Disturbance Rejection?