Originally Posted by Graviman
IFMU, agreed duty cycle would be nP, but one of the X2 suite of technologies is active vibration control. There will be an accelerometer somewhere in the hub which alters the input signal to the hydraulic servo dual valves.
Mart,
Don't forget back in post 24 you asked:
I'd be interested to know more about the Moog active vibration control though. I could have a reasonable guess at how it might work, but will dig up some papers.
And Nick replied in post 25:
Originally Posted by NickLappos
Grav,
The Moog system is the same as that in the S-92, and it works like a charm. I understand the EC225 has a similar system.
The Moog vibration absorber is a electronic motor is digitally controlled to have very precise rpm capability. The digitally controlled motor spins counter rotating weights which are driven eccentrically in and out by separate jackscrews to produce higher or lower vibration amplitudes. Because the rpm of the motor is precisely controlled, the phase of the counterrotating weights can be adjusted, where the phase is the precise direction of the maximum amplitude of the weights. As a result the vibration absorber is capable of being adjusted to precise RPMs and to precise vibration absorbtion direction (lateral, vertical, horizontal). It can also be adjusted automatically by a computer as the aircraft flies. A vibration pickup is located near the place where you want to quell a vibration the most. Using that pickup the computer determines the best way to tune the weights to drive the rpm to its lowest. The computer uses precise logic that learns as the flight conditions change and so the computer becomes specific for the aircraft it is installed in. You can use up to six absorbers with the computers so that it's quite possible to quell the vibration across a very large area. Each of the absorbers weighs around 40 pounds and the amplifier maybe 10 pounds.
Try this patent number: 6,869,375