One of the experiments I had intended to do (whenever we got around to driving the motors) was to do a bode plot on the gizmocopter schematics by running a swept sine wave through the motor controller and measuring the response on our gyros. I suppose we could measure just the motors themselves by doing a similar experiment with one motor and a strain guage.
-----Original Message----- From: John Carmack [mailto:[EMAIL PROTECTED]] Sent: Wednesday, September 18, 2002 11:33 AM To: [EMAIL PROTECTED] Subject: RE: [ERPS] Antimatter research vs Gizmocopter At 11:05 AM 9/18/2002 -0700, you wrote: >I managed to write a bit of code which quadruples my DOS machine's systick >rate and spits out the appropriate width pulses needed to drive our >off-the-shelf motor controllers. This works fine, but I don't know how >translatable it would be to our target Linux machine. That should be one of the things you can do well with RTLinux. >The issue I have with the serial PWM controllers is that you'ld be looking >at about a 20 mSec lag that would be introduced in your control loop. By my >calculations, a 20mSec lag translates as a 72 degree lag for a 10Hz >bandwidth control loop, which sounds pretty awful to me. But servo wasn't >really my forte, so we shall see. > >Bill Think in terms of what the actuator is actually going to do -- say you have your rotor spinning at hover speed, probably about 90% of peak RPM, and you increase or decrease speed. How much is the RPM actually going to change in 20 msec? That large inertia in the rotors are going to be one big difference between POGO and gizmocopter. You should make time/RPM graphs of accelerating at full power from a dead stop to max rpm, then coasting back down to zero lift level to determine how important this is. John Carmack _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
