[Dprglist] Fwd: LF intersection angle rule

Carl Ott carl.ott.jr at gmail.com
Sun Dec 10 10:51:29 PST 2017


you've shared those videos before - fun for speed even if the line is
rather boring :)...

you mentioned no plans to field a robot - why not?

e.g. You could field the first line-following bipedal walking robot in the
club, and give Ron and I a 'run' for the money...


On Sun, Dec 10, 2017 at 11:51 AM, David Anderson <davida at smu.edu> wrote:

> 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>
> 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> 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>
>> 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-Roboram
>>> a-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>
>>> 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>paradug at gmail.com>
>>>> To: John Swindle < <swindle at compuserve.com>swindle at compuserve.com>
>>>> Cc: DPRG < <dprglist at lists.dprg.org>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>
>>>> 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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