On Wed, 2002-09-18 at 20:52, [EMAIL PROTECTED] wrote: > But an even bigger problem is a close coupling between the attitude sensors > and the differential throttling. The bad news is the difficulties associated > with attitude sensors, but I won't get into that, this message; that is another > thick book. I would be inclined to include some sort of hard-wired loop > between the attitude sensors and the differential throttling, so that the > darn thing has some tendency to want to fly straight and level. >
We aren't quite doing a hard-wired loop, but we are pretty close. We have a realtime, interrupt driven thread reading the gyros, doing a quick control calculation, and writing the motors. At a higher level in the code, "hands off" is hover. At least that is the theory. On the motor control itself, one of the things I like about the DAC is that you write the four channels, then a read from one of the channels actually loads the values to the channels. All four motors are updated simultaneously. > At the ConJose party, someone mentioned Futaba R/C Helo gyros. If I understand > correctly, these sense either absolute position or angular rate, and generate > a signal that R/C servos (or some R/C receivers) understand, which modifies > the commands from the Radio Control receiver to the servos, making the helo > more stable (if that is not an oximoron). If this is the case, then > encorporating these into a hard-wired control loop would affect the design, > biasing it towards an R/C servo-like signal. Since R/C servo pulses are > another pulse-position/pulse-width signal, they could be generated by a > similar DAC->monostable(555) or programable timer arrangement, only slightly > different from the PWM motor controller. Current gyros are rate gyros from a gyro mouse. We will want to replace them. Futaba R/C gyros might be a possibility, we are also considering higher end gyros. The issue being how good do we really need vs. how much can we afford. Dave _______________________________________________ ERPS-list mailing list [EMAIL PROTECTED] http://lists.erps.org/mailman/listinfo/erps-list
