Quote:
Originally Posted by Tom Line
By design. As someone else already stated, the metronome, or 'wait' in Labview means 'execute no FASTER' than your set time.
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Yet in all of the data the avg loop time is less than the set loop time. In the roborio 20ms loop time, there are loop times of 8,9 & 10ms.
This effectively, doubled the PID gains for these loops... Again we really did not see any issue with the elevator with stability.. and as MrRoboSteve pointed out it is probably a better solution to incorporate the delta-t at this high school level, just in case the field impacts the control.
We had no programmers with calc yet this year, so we used NXT lego line following example as the start of the conversation, and 3 weeks later, ended with the white paper on the SRX internal PID code. The elevator code ended up with a separate P gain for raising the elevator, and a lower P gain for lowering the elevator, along with the SRX "IZone" implemented. This gave a very quick reacting and stable control for the elevator system. The mechanical gear ratio went from 35:1 minicim at Waterford, to 20:1 CIM at Championships.