[chbot] A possible challenge

[Synco Reynders]

Interesting idea... couldn't help but run some numbers.... I get:
So firstly 1acre is ~4000m^2, or a ~63m square field.
Assuming the robot is ~ 0.5 wide, and we were to do a full sweep of
the field in half a day (12 hours), we get:
Total distance traveled ~ (63 * 2) * 63 = 8000m
Average speed ~ 8000/12/3600 = 0.2m/s

I just happened to have a bag of walnuts and found:
~50 walnuts fit in a 1 litre container
A dried walnut weighs about 6grams so budget 10g for a fresh one.
Assuming a walnut is spherical ~30mm diameter

Next guess energy consumption... Thinking back to the days of driving
my RC car around... it had a 700mAh battery and it would last ~10min.
So to last a full acre we need: 12hrs * 6 * 0.7Ahr =~ 50Ah which is
~5kg of LiPo batteries (assumes 1000mAh is ~100g)
or ~250g of fuel (can be petrol/diesel/kerosene and assumes 33% conversion loss)

So far, I'd suggest using a little petrol motor which generates
electricity / (drives pneumatic pump?) to get duration and a quick
turn-around time.

Now the mechanics... I'll let someone else design this.
Hope this has helped.
/s




On 10 October 2011 21:23, Robin Gilks <robin at gilks.org> wrote:
> Greetings
>
> I'm just starting to put together the specs for a challenge to make a
> walnut picker-upper - nuts in NZ are picked from the ground having dropped
> naturally rather than the tree being shaken - it avoids having to remove
> the husk.
>
> So far I have the following criteria:
>
>  * cover 1 acre of ground in 0.5 days, repeating for about 5 weeks
>  * avoid trees and irrigation nozzles (tricky as that is where most of the
> nuts land)
>  * return 'home' to empty and recharge. Not sure about the total load
> expected from an acre but during the 0.5 day cycle it would only be a few
> kg.
>  * recharge can be by battery exchange or refilling with
> diesel/unobtainium to reduce turn-around time
>
> Up to the next meeting I'll assemble some pictures of manual devices that
> may be adaptable.
>
> You may have guessed that I'm not thinking at toy level here :)
>
> --
> Robin Gilks
>
>
>
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