[Dprglist] Pat's robot

[Pat Caron]

David, I thought that I had mechanical issues two meetings ago, but I have
since eliminated most of them as the robot now travels fairly straight (on
a ceramic tile floor).  I thought that possibly the axle shaft(s)
were slipping at the wheels or drive pulleys.
I have found a couple of bugs in my program, but the biggest find was the
4mm (~1/4") difference in circumference on the tires as was suggested to
check during the Feb 18th meeting.  I had been using wheel diameter in my
calculations!
I am looking to find a large flat space in our covid world that will allow
me to do the straight line and UBMmark as suggested.

Thanks for the calibration instructions!

...Pat C.


On Wed, Mar 2, 2022 at 2:30 PM David P. Anderson via DPRGlist <
dprglist at lists.dprg.org> wrote:

> Howdy DPRG,
>
> At the meeting last night we talked about ways to use testing to measure
> a robot's performance, and I pointed Pat to a webpage on odometery
> calibration.  But I don't want to get the cart before the horse here.
>
> Pat, you mentioned that there might be some mechanical issues and those
> should of course be addressed first.
>
> I've found it useful to strip down to the simplest exercises. You might
> consider finding a nice flat long place, turn off odometery/navigation,
> and just set the robot's speed controllers to run both motors at the
> same speed.  Then point it down the hallway or whatever and let it go.
> Do this a couple of times. Does it tend to drift right or left?  Can you
> ascertain that the chassis is straight and the wheels are parallel?  Is
> there slippage in the drive train?   The wheel-to-shaft coupling?  The
> tire to wheel attachment?  And so on.
>
> I would nail down the mechanical issues first before looking at
> odometery calibration and so on.
>
> cheers!
>
> dpa
>
>
>
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