Quote:
Originally Posted by Ether
Very noticable quadrature error.
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Yes, and the duty is not very close to 50%, either.
The two channels will be useful for telling which direction the motor is turning. Using more than the rising (or falling) edges of one channel will add jitter to the speed measurement, making the speed loop either less effective, or increasing sensitivity of its stability on tuning.
In a shooter geared 2:1 per Ether's recommendation, this gives maybe 7 or 8 useful speed samples during the loaded part of a shot. The speed regulator will be trying to boost voltage to compensate that ~ 8 millisecond load transient, with boost adjustments 16 times per millisecond (controller output modulation frequency). It will be interesting to see how well the 775pro, this encoder, and a Talon SRX can regulate wheel speed during a shot load. Factors to influence the regulation include shooter wheel moment of inertia, speed regulator tuning, supply voltage feed-forward, ball compression, wheel compression, wheel-to-ball friction, etc.
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Richard Wallace
Mentor since 2011 for FRC 3620 Average Joes (St. Joseph, Michigan)
Mentor 2002-10 for FRC 931 Perpetual Chaos (St. Louis, Missouri)
since 2003
I believe in intuition and inspiration. Imagination is more important than knowledge. For knowledge is limited, whereas imagination embraces the entire world, stimulating progress, giving birth to evolution. It is, strictly speaking, a real factor in scientific research.
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