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<p>I recommend to use three different positions for the chip kick.
As I have implemented our chip kick detection I am well aware of
the difficulties of detecting such kicks. I suggest the following
positions:<br>
- From a corner to the center of the field. This is most difficult
to detect as the ball goes through the camera axis and does not
show a parabola in the images.<br>
- From a corner along the long side of the field. Here, a single
camera is available as well but the ball shows a significant
parabola. The ball may vanish from the images at its high points.<br>
- From the center to the goal or vice versa. This is most simple
as the ball is visible on multiple cameras, basically providing
you stereo vision.<br>
<br>
We used these exact position at IranOpen. Furthermore, we used
distances from 2 - 3.5m. Basically, we had 2m, 2.5m, 3m, and 3.5m
in the bucket. Then we drew them in random order. Thereby, each
team gets the same chips, but cannot predict the order they were
executed. To speed up the challenge, this can certainly be reduced
to two distances. The technical difficulties of the different
positions might be used to weight scores.<br>
</p>
<p>Cheers,<br>
<br>
Andre Ryll<br>
<font size="-2">Project Leader & Founder of<br>
TIGERs Mannheim<br>
</font></p>
<br>
<div class="moz-cite-prefix">Am 24.07.2017 um 19:26 schrieb Danny
Zhu:<br>
</div>
<blockquote type="cite"
cite="mid:af2f7f32-c49f-22c6-d563-8652e0f8b006@cs.cmu.edu">That
sounds reasonable to me, though I think we'll need to see it in
practice. If the range needs to be wider, we can always add
variation in the commanded distance as well. The exact
distribution within the range shouldn't matter much, as long as
the same thing is done for all competitors, right?
<br>
<br>
Danny
<br>
<br>
On 07/24/2017 07:18 PM, Alexander Danzer wrote:
<br>
> That's a good point.
<br>
>
<br>
> However, when I investigated the possibilities of chip kick
estimation,
<br>
> I found that only considering a robot's orientation does not
provide enough
<br>
> precision for determining the kick's direction precise enough
<br>
> for a distance of more than 3 meters.
<br>
>
<br>
> But we certainly should have some variety in the distance.
When I wrote
<br>
> 3.5 meters, I had in mind that the kick was performed with an
ER-Force
<br>
> robot, which has significant variations in the actual kick
distance.
<br>
> I would estimate deviations of around 20 centimeters for said
distance,
<br>
> but I have to check our current hardware tomorrow.
<br>
>
<br>
> So, what do you think of a distance in the range of 3.0 to
3.5 meters?
<br>
> (with an ER-Force robot, this is quite hard to guarantee
however with
<br>
> an equal probability distribution).
<br>
>
<br>
>
<br>
> On 2017-07-24 18:55, Joydeep Biswas wrote:
<br>
>>> On Jul 24, 2017, at 6:22 PM, Alexander Danzer
<a class="moz-txt-link-rfc2396E" href="mailto:alex@dnzr.name"><alex@dnzr.name></a> wrote:
<br>
>>>
<br>
>>> The ball touches ground after 3.5 meters in field
plane.
<br>
>>
<br>
>> If the chip kick distance is fixed, then the intercepting
robot only
<br>
>> needs to know the kicking robots orientation when the
ball is kicked -
<br>
>> it does not really need to do chip kick estimation.
<br>
>>
<br>
>> -Joydeep
<br>
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