[Dprglist] From DPRG RBNV last night - about that heading loop glitch when rotate CW from 360 thru 0

[David]

Carl,

Excellent!

The robot seems to rotate in place really well.  And with the IMU for 
direction, the wheel slippage is greatly minimized.  Good demo.  You 
have to have a lot of stuff working to make that happen.

I never had a lazy susan for such precise testing.  But back when I had 
a station wagon I used to put jBot in the back, turn it on set up to 
point North, and watch it rotate while we drove around, just for grins. 
     Good stuff.

onward!

dpa


On 3/24/21 8:13 AM, Carl Ott via DPRGlist wrote:
> As discussed last night.
>
> Karim was right - it was easy.
>
> Plus - we now have */additional proof that _algebra doesn't work on 
> the weekends when the weather is nice outside_./*
>
> instead of cancelling out to zero, this term somehow wound up getting 
> doubled
> image.png
>
> the ugly logic below still wants to be simplified & cleaned up.  But 
> at least it now works correctly:
>
> the method below calculates *fbTerm* for this summing node
>
> *setpoint - fbTerm = loop error *
>
> where *setpoint *has range [ 0 .. 360 ]
> where*IMU outputs* [ 0 .. 360 ]
> and where *error *has range [ -180 .. +180 ], to give the shortest 
> rotation from current to setpoint
>
> image.png
>
> Anyhow...
> Now onto cleanup, then to actually tuning the loop, then finally to 
> more interesting behaviors...
>
> Carl
>
>
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