On Fri, 2004-01-02 at 00:21, John Carmack wrote: > Can you describe the complete sensor / computation / actuator system for > gizmocopter?
Sure - I'll also include a few more notes that did not make into the previous email. Spec is for a gyro and accelerometer in each axis, control is done with two threads - a hard real-time stability augmentation and a non-real-time command augmentation. The stability thread is a simple proportional-derivative control off the gyros which then converts the resulting pd vector into 4 integers for the relative motor speeds. The motor control variables are sent via serial to a BasicStamp that converts the integers to standard R/C control signals. The command augmentation is a PID control on the combined gyros and accelerometers (and anything else we decide to add). The command augmentation does all the higher level work - rotations, integrations and derivatives to determine what it is doing; massaging the incoming joystick commands for the stability thread; telemetry; etc. What we actually flew was just the stability thread - without calling from the real time interupt (we called it from a timed loop) and without actually reading the instruments. We "flew" it completely by hand - or rather I should say we bounced it around on its two inch tether. What we were after was more or less three things - do we have enough power for the weight to actually fly? (yes), How long do the new battery packs last? (two packs - 1 minute flight duration, and we have a few seconds between noticeable engine slowdown and engine cutoff), and what should the constants on the control loop be? (the first test was way off - this test was close, and about an order of magnitude less). I was able to actually have some control over the bouncing around, including the rate at which it hopped from leg to leg. Anyway, we still have a long way to go, but at least we are making progress again. Dave -- David Masten <[EMAIL PROTECTED]> _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
