[Dprglist] Fwd: LF intersection angle rule
Doug Paradis
paradug at gmail.com
Sun Dec 10 11:23:26 PST 2017
Carl,
Seeing Ron and you go at it has bee inspirational. I have learned a lot
just watching the progress both of you have made. In fact, I considered
scoping out what it would take to use the little red hexapod I demoed at
the November meeting. That would be cool, but 2018 is the year of the
Rover for me.
--Doug P.
On Sun, Dec 10, 2017 at 12:51 PM, Carl Ott <carl.ott.jr at gmail.com> wrote:
> David,
>
> 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...
>
> Carl
>
> 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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