[Dprglist] Fwd: LF intersection angle rule
David Anderson
davida at smu.edu
Sun Dec 10 09:51:45 PST 2017
I did see Ron's robot demo, and interesting contrast between his
approach and Carl's, though Carl's is admittedly a simulation at this
point.
Carl says that this year he is going to "get physical" so I was about to
post a link to Olivia Newton-John's "Let's Get Physical" as a theme
song. But then I went back and read the lyrics, and all the thinly and
not-so-thinly veiled innuendo from 1980's disco seem oddly discordant
in today's cultural environment ("I've been patient, I've been good.
Trying to keep my hands on the table").
So instead I offer the following, in keeping with the line-following
theme and the observation that all robot contests eventually devolve
into races. Even if the requirements are, say, that only
line-following WALKING robots are allowed:
<https://www.youtube.com/watch?v=4XiRxNkZleY>
https://www.youtube.com/watch?v=4XiRxNkZleY
cheers!
dpa
On 12/10/2017 11:32 AM, Doug Paradis wrote:
> David,
> From watching actual robots run the stain elements, I know that
> it very possible for the robot to follow the outside edge of the stain
> and recover the line on the opposite side (my robot did this for one).
> Following this path the robot would be considered not following the
> line. Again after watching multiple robots navigate the S curves, it
> is easy to see if the robot is following the line (I.e., swaying with
> the S curve) versus just cutting across the center line (i.e., not
> following the line). I agree that bigger robots, those with wheel
> bases larger than the maximum radius of curve used in the course
> (i.e., 6 inches), might not be as responsive as the smaller robots.
> However, I still believe that you can tell when they are not following
> the line.
>
> BTW, did you see Ron's robot demo on Saturday? His robot was
> doing pretty well. I think the course he was running had a S curve
> which he handled without issue. The practice course didn't have any
> stains, if I recall right.
>
> Regards,
> Doug P,
>
> On Sun, Dec 10, 2017 at 10:49 AM, David Anderson <davida at smu.edu
> <mailto:davida at smu.edu>> wrote:
>
> Thanks Doug,
>
> I'm not sure I follow your examples (pun intended!).
>
> For the segmented S curves, the difference between following the
> arc and following straight line approximations of that arc are
> pretty small, and likely to be indistinguishable from Ron's
> robot's path, for example. Similarly, each of the stains on the
> published "challenge" course is on a straight line segment between
> the entry point and exit point, so the paths would be identical in
> both cases.
>
> For a robot with a base the size of the tiles, I'm not sure there
> would be any difference at all, unless the rules require that the
> "exact center" of the robot must remain on the line, in which case
> I don't see how either Carl's approach or Ron's would qualify.
>
> This is just an intellectual exercise, I'm not planning on
> fielding such a 'bot.
>
> cheers!
> dpa
>
>
>
> On 12/10/2017 10:06 AM, Doug Paradis wrote:
>> David,
>> Going from entry point to exit point is not considered
>> enough. You have to follow the line. For example, the segmented S
>> curves, the robot needs to follow the curve and make an S type
>> movement. Another example is the stain elements, the robot needs
>> to follow the line across the stain not follow the outside edge
>> of the stain.
>>
>> Regards,
>> Doug P.
>>
>> On Sun, Dec 10, 2017 at 1:11 AM, David Anderson <davida at smu.edu
>> <mailto:davida at smu.edu>> wrote:
>>
>> Great meeting today.
>>
>> Doug, I have a question based on Ron and Carl's
>> presentations, perhaps it has already been answered, to wit:
>>
>> As I understand, the line following course consists of an
>> assembly of square tiles, each of which has an entry and exit
>> point.
>>
>> Is it sufficient for the robot to just identify the entry and
>> exit points, and drive directly from one to the other?
>>
>> That is, it would not follow the line per se, though with
>> sufficiently large robot the differences would probably be
>> pretty negligible, but it would follow the course.
>>
>> thanks,
>> dpa
>>
>>
>>
>> On 12/09/2017 08:18 AM, Doug Paradis wrote:
>>> John,
>>> Currently, the intersecting lines are always straight
>>> and all intersections are 90 degrees. Curves lines at an
>>> intersection would be a possible addition to further
>>> challenge courses (interesting idea). The link to the course
>>> layout is at
>>> https://www.dprg.org/wp-content/uploads/2017/11/DPRG-Roborama-2011b-Challenge-Level-LF-Course.pdf
>>> <https://www.dprg.org/wp-content/uploads/2017/11/DPRG-Roborama-2011b-Challenge-Level-LF-Course.pdf>
>>> If you have any additional questions, let me know. I would
>>> love to see your work on the tests that you are developing.
>>>
>>> Regards,
>>> Doug P.
>>>
>>> On Sat, Dec 9, 2017 at 12:36 AM, John Swindle
>>> <swindle at compuserve.com <mailto:swindle at compuserve.com>> wrote:
>>>
>>> Doug,
>>>
>>> I'd say the crossing in your drawing was about either 30
>>> degrees or 150 degrees, and since it could come in on
>>> either side, I'd have to look for both. I am not asking
>>> that the rules state which side the angle is measured
>>> from. My issue is that I am developing a two-step test
>>> that covers all the conditions in the Challenge, but in
>>> the steps I need to include something that rejects the
>>> intersections. I am OK with rejecting any line that is
>>> 70 degrees to 110 degrees on either side. If the
>>> intersecting line is straight, the test is a bit more
>>> robust. If each side is 70 to 110 degrees (a bent
>>> intersecting line), my two-step test might fail.
>>>
>>> Doing it "that's just wrong" way,
>>> John Swindle
>>>
>>>
>>> -----Original Message-----
>>> From: Doug Paradis <paradug at gmail.com
>>> <mailto:paradug at gmail.com>>
>>> To: John Swindle <swindle at compuserve.com
>>> <mailto:swindle at compuserve.com>>
>>> Cc: DPRG <dprglist at lists.dprg.org
>>> <mailto:dprglist at lists.dprg.org>>
>>> Sent: Fri, Dec 8, 2017 11:52 pm
>>> Subject: Re: LF intersection angle rule
>>>
>>> John,
>>> In the challenge course, all the intersections are
>>> 90 degrees. The rule was written to allow crossing
>>> variations in the future. I'm thinking that 70-90
>>> degrees would represent the smallest angle of the
>>> intersection. I not sure that is right, just the way I
>>> would interpret the angle.
>>> if you saw an intersection that was like this:
>>> | /
>>> | /
>>> /
>>> / |
>>> / |
>>> / |
>>>
>>> What angle would you say the intersection was?
>>>
>>> Regards,
>>> Doug P.
>>>
>>> On Fri, Dec 8, 2017 at 9:03 PM, John Swindle
>>> <swindle at compuserve.com <mailto:swindle at compuserve.com>>
>>> wrote:
>>>
>>> Doug,
>>> The Line Following Challenge rules say
>>> "Intersections may cross with angles of 70 - 90
>>> degrees." Doesn't that really mean 70 to 110
>>> degrees? Is the intersecting line straight, or can
>>> it bend at the intersection?
>>> Thanks,
>>> John Swindle
>>>
>>>
>>>
>>>
>>>
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