1. P3K RTC Algorithm/Controls Mitchell Troy With much thanks to Chris Shelton System Engineering meeting 8/9/2007

2. 2 Modal Versus Zonal Control Assume A=# Actuators, M=# modes to control, S= # of slope measurements, G = M gains (one for each mode) Zonal control –1 matrix multiply (S by A matrix) Modal control option #1 –2 matrix multiplies (S by M and M by A matrices) –M can be as large as A –Allows for on-fly adjustment of gains for each mode Model control option #2 –1 matrix S by A –Adjust modal gains (G) offline and generate control matrix ( (S by M) X G X (M by A)) offline –Must be able to hot swap reconstructors Suggested requirement: –Single matrix multiple S X A –Must be able to hot swap reconstructors

3. 3 Woofer/Tweeter Control How do we split the Woofer/Tweeter commands? Two basic methods 1.Split commands based on spatial frequency 2.Let tweeter DM do everything and then offload to woofer If split based on spatial freq. –Still MAY need to handle saturation on tweeter If split based on temporal freq. –Might get better temporal correction using both DMs GPI PDR Design –Current design splits spatially –Does not appear to handle saturation of tweeter! Shelton’s suggestion for P3K –Implement BOTH

4. 4 GPI AO block diagram Slide curtsey of Jean-Pierre Véran from GPI

5. 5 P3K AO block diagram

6. 6 Discussions/Issues Is the offload from tweeter to woofer going to the correct place? We should eventually design the whole P3K control design (don’t forget): –design the TT path for woofer and TTM –Leaky terms