[EMAIL PROTECTED] wrote: > did you find out how fast you could get away with sampling the various > devices? I have some robot applications where I found that if I sample > the data too fast I get different result than if I give things a chance > to settle. Its a function of the device you are measuring.
This is a good point. It would be nice if we could at least design the embedded system to vary the sample rate and demonstrate that things tracked as expected. We could also demonstrate/verify the upper bound on sampling rate. Bench testing on the old IMU looked very reasonable. The histograms were good Gaussians, and at least for the accelerometers, the widths were about what was expected. The old gyros weren't very well documented. (The new IMU should have much better gyros in it :) Given that the roll gyro gave reasonable data during earlier LV1b flights, and that the pitch/yaw circuits were topologically identical, It seems likely that the pitch/yaw data is in some way meaningful. The DC average pitch/yaw during flight is zero, so a noisy-looking signal is actually a reasonable result. The vibrational environment ought to be estimable from the accelerometer data. When the new IMU is online, hopefully we'll have the software ready to do realtime attitude estimating, not on the bench, but possibly near the bench. The old IMU did seem to give good pitch/yaw info. at least in a low dynamic environment. You could pick up the avionics module and twist it about pitch/yaw and see reasonable results on the realtime display, though nothing was being integrated to find attitude. ------------------------------------------------------------------------------ A democracy cannot exist as a permanent form of government. It can only exist until the voters discover that they can vote themselves largesse from the public treasury. From that moment on, the majority always votes for the candidates promising the most benefits from the public treasury, with the result that a democracy always collapses over loose fiscal policy, always followed by a dictatorship. The average age of the world's greatest civilization has been two hundred years. These nations have progressed through this sequence: From bondage to spiritual faith; from spiritual faith to great courage; from courage to liberty; from liberty to abundance; from abundance to [selfishness; from selfishness to] complacency; from complacency to apathy; from apathy to dependence; from dependence back again into bondage. -- Scottish historian Alexander Tyler on the fall of the Athenian republic. The bracketed portion on ``selfishness'' appears in only some citations, and the term here means pathological acquisitiveness and a preference for short term advantage at the expense of long term disadvantage _______________________________________________ psas-software mailing list firstname.lastname@example.org http://lists.psas.pdx.edu/mailman/listinfo/psas-software