[Dprglist] Fwd: LF intersection angle rule

Doug Paradis paradug at gmail.com
Sun Dec 10 10:29:23 PST 2017

      I agree about that all robot contests eventually devolve into races.
Especially after multiple people have solved the problems of the contest.
It is possible to give points for subjective attributes of the robot, but
that can be a slippery slope. The winner of Table Top this year, was an
example of a robot that was extremely cool. I competed in that contest and
even if my robot (Little Andy) had beat his time, my robot was nowhere as
cool as his. Luckily, that wasn't an issue since my robot screwed up.

      However, I don't think that the eventual devolution of robot contest
into races is the point. I think that the solving of the problems of the
contest is the fun and interesting part. Also, after you have several
people who have solved the problem, especially if they used different
approaches initially, it is fun to see which approach wins the day or how
far you can take your robot. I do think there should be a lifetime to a
specific contest. Sometimes you can extend a contest by adding new
challenges. I believe DPRG's table top contest and RoboColumbus are
examples of this. The trick is to know when to give the contest a rest.
When you give a contest a rest, you shut the door for new people who might
be interested is solving that contest's challenges.  I would still like
another shot at making a cool Table Top robot.

      There has to be an entry point for new roboticists to gain skills and
also a challenge point where people can continue to develop. Maybe, an
approach would be to set a "challenge" that is really hard, like the
Challenge LF course, and leave the challenge standing until someone solves
it. If both Carl and Ron manage to solve the Challenge LF course this May,
I will enjoy both of their efforts, even if the winner is the fastest of
the two.

Doug P.

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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