Go to Post Limits are imposed by both man and nature. Understanding those limits and attempting to push past them is the basis of creativity. - Dave.Norton [more]
Home
Go Back   Chief Delphi > Competition > Rules/Strategy
CD-Media   CD-Spy  
portal register members calendar search Today's Posts Mark Forums Read FAQ rules

 
Closed Thread
Thread Tools Rate Thread Display Modes
  #16   Spotlight this post!  
Unread 07-01-2009, 11:19
kirtar kirtar is offline
Alumnus
FRC #0461 (Westside Boiler Invasion)
Team Role: Alumni
 
Join Date: Jan 2008
Rookie Year: 2007
Location: West Lafayette, IN
Posts: 169
kirtar will become famous soon enough
Re: Underestimating the Trailer

Quote:
Originally Posted by Petey View Post
I bet it'd be hard, but I'm pretty sure it's possible. You don't need a square chassis, all you need is a way to construct your back end in such a way that the sides of the hexagon abut the back end of your bot while the trailer tongue is pulled pretty far in while also observing the other rules about attaching easily and not hitting the walls before bumpers.

e: what's the shear strength of the bolt?

Just remember that the hitch has to be on the bumper perimeter. Even if you put an indentation, the outer vertices would still define a polygon which would put your hitch not on the bumper perimeter.

Also, to EricH, you only need bumpers on 2/3 of the bumper perimetier. The entire bumper perimeter exists whether on not there are bumpers on the robot.
__________________
  #17   Spotlight this post!  
Unread 07-01-2009, 11:28
=Martin=Taylor= =Martin=Taylor= is offline
run the trap!!!
FRC #0100 (The Wild Hat Society)
Team Role: Human Player
 
Join Date: Feb 2006
Rookie Year: 2005
Location: Bezerkeley, California
Posts: 1,255
=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute
Re: Underestimating the Trailer

Quote:
Originally Posted by Petey View Post
Something to think about:

Can you build a robot in such a way that the trailer's wheels are always oriented like the robot's?
Whats the advantage?

If you're dragging the trailer wheels sideways while you turn your gonna make steering much harder.

We've found that jacknifing the robot/trailer back and forth quickly is a great way to steer. Seems to work better than just plain tank steering.
__________________
"Cooperation; because life is a team sport"
-Philip J. Fry
  #18   Spotlight this post!  
Unread 07-01-2009, 11:55
Anna B.'s Avatar
Anna B. Anna B. is offline
has lots of NASA swag!
AKA: Anna
FRC #1735 (Green Reapers)
Team Role: Programmer
 
Join Date: Sep 2008
Rookie Year: 2007
Location: Worcester, MA
Posts: 85
Anna B. is a glorious beacon of lightAnna B. is a glorious beacon of lightAnna B. is a glorious beacon of lightAnna B. is a glorious beacon of lightAnna B. is a glorious beacon of lightAnna B. is a glorious beacon of light
Re: Underestimating the Trailer

Quote:
Originally Posted by Hachiban VIII View Post
We've found that jacknifing the robot/trailer back and forth quickly is a great way to steer. Seems to work better than just plain tank steering.
Exactly. Instead of fighting it, why not work with it?
__________________
raising my parents blood pressure since '94

the best numbers are made up numbers

"let's call the four things A, G, Semicolon, and Pointy"

Maxima debetur puer reverentia
The greatest respect is due a child (Juvenal)
  #19   Spotlight this post!  
Unread 07-01-2009, 12:26
pfreivald's Avatar
pfreivald pfreivald is offline
Registered User
AKA: Patrick Freivald
FRC #1551 (The Grapes of Wrath)
Team Role: Mentor
 
Join Date: Jan 2007
Rookie Year: 2001
Location: Naples, NY
Posts: 2,304
pfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond repute
Re: Underestimating the Trailer

Quote:
Originally Posted by Hachiban VIII View Post
We've found that jacknifing the robot/trailer back and forth quickly is a great way to steer. Seems to work better than just plain tank steering.
What kind of drive train did you use when you were jacknifing to steer? Tank? 4WD?

Thanks,

Patrick
__________________
Patrick Freivald -- Mentor
Team 1551
"The Grapes of Wrath"
Bausch & Lomb, PTC Corporation, and Naples High School

I write books, too!
  #20   Spotlight this post!  
Unread 07-01-2009, 12:38
Swerting's Avatar
Swerting Swerting is offline
King of the Geats
FRC #1523 (MARS)
Team Role: Mentor
 
Join Date: Jan 2009
Rookie Year: 2004
Location: United States
Posts: 14
Swerting is on a distinguished road
Re: Underestimating the Trailer

My team made a basic tank drive chasis from VeX kits, hooked up a trailer (also made of VeX) and drove it on a smooth table (the wheels being gears) and while it did seem to jacknife(?) quite a bit it didn't seem to matter too much since the wheels also slid fairly easily.

of course, it's just VeX on a smooth table, and it may be entirely different in competition
__________________
Six weeks is plenty of time to design and build a robot.
What do you mean that includes testing it?!?

I will forever see the first logo in my sleep.
  #21   Spotlight this post!  
Unread 07-01-2009, 12:51
eschanz's Avatar
eschanz eschanz is offline
B.A.
AKA: Evan Schanz
FRC #1254 (Entropy)
Team Role: Human Player
 
Join Date: Dec 2008
Rookie Year: 2008
Location: Decatur, Michigan
Posts: 19
eschanz is infamous around these partseschanz is infamous around these parts
Send a message via Yahoo to eschanz
Exclamation Re: Underestimating the Trailer

I dont think it will be as hard as people are saying, because with less friction it will be close to impossible to get jack-knifed. This is because when you slide, the force from hitting a wall or another bot will send the trailer flying past or hit the wall (or bot) too.
  #22   Spotlight this post!  
Unread 07-01-2009, 12:53
JesseK's Avatar
JesseK JesseK is offline
Expert Flybot Crasher
FRC #1885 (ILITE)
Team Role: Mentor
 
Join Date: Mar 2007
Rookie Year: 2005
Location: Reston, VA
Posts: 3,722
JesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond reputeJesseK has a reputation beyond repute
Re: Underestimating the Trailer

FYI, unless there's something that I missed you cannot move the hitch location once the match has started. The rule regarding the trailer hitch says a rigid, fixed location which has been interpreted by most to mean that the hitch cannot be actuated.

As for detecting the trailer location, you could have ultrasonic sensors pointed out the back of the bot to where the tongue meets the trailer. If the trailer swings to one side, the range finder on that side will get shorter and the range finder on the other side will report a longer range or just noise. Of course, this assumes you already have a crab drive system and there's an actual benefit to keeping your robot wheels oriented with the trailer wheels.
__________________

Drive Coach, 1885 (2007-present)
CAD Library Updated 5/1/16 - 2016 Curie/Carver Industrial Design Winner
GitHub
  #23   Spotlight this post!  
Unread 07-01-2009, 15:04
EricH's Avatar
EricH EricH is offline
New year, new team
FRC #1197 (Torbots)
Team Role: Engineer
 
Join Date: Jan 2005
Rookie Year: 2003
Location: SoCal
Posts: 19,825
EricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond reputeEricH has a reputation beyond repute
Re: Underestimating the Trailer

Quote:
Originally Posted by kirtar View Post
Also, to EricH, you only need bumpers on 2/3 of the bumper perimetier. The entire bumper perimeter exists whether on not there are bumpers on the robot.
That's what I said. You only need 2/3 of it (the perimeter). Though maybe I should have added "covered" to the end.

Also note, though this is not official by any means: the trailer hitch will (most likely) take up 7" of the 1/3 uncovered. I don't think the GDC will rule that it's a bumper...
__________________
Past teams:
2003-2007: FRC0330 BeachBots
2008: FRC1135 Shmoebotics
2012: FRC4046 Schroedinger's Dragons

"Rockets are tricky..."--Elon Musk

  #24   Spotlight this post!  
Unread 07-01-2009, 19:42
=Martin=Taylor= =Martin=Taylor= is offline
run the trap!!!
FRC #0100 (The Wild Hat Society)
Team Role: Human Player
 
Join Date: Feb 2006
Rookie Year: 2005
Location: Bezerkeley, California
Posts: 1,255
=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute=Martin=Taylor= has a reputation beyond repute
Re: Underestimating the Trailer

Quote:
Originally Posted by pfreivald View Post
What kind of drive train did you use when you were jacknifing to steer? Tank? 4WD?

Thanks,

Patrick
4WD "long" configuration.

Tank steering.
__________________
"Cooperation; because life is a team sport"
-Philip J. Fry
  #25   Spotlight this post!  
Unread 07-01-2009, 20:01
pfreivald's Avatar
pfreivald pfreivald is offline
Registered User
AKA: Patrick Freivald
FRC #1551 (The Grapes of Wrath)
Team Role: Mentor
 
Join Date: Jan 2007
Rookie Year: 2001
Location: Naples, NY
Posts: 2,304
pfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond reputepfreivald has a reputation beyond repute
Re: Underestimating the Trailer

Quote:
Originally Posted by Hachiban VIII View Post
4WD "long" configuration.

Tank steering.
That's nice to know. We only have a single 4x8 sheet of the FRP so far, and we were looking at 4WD tank steering, probably wide configuration... As a team that experiences a lot of ice and snow on a regular basis, we've been thinking about 'using the slipperiness' instead of somehow trying to fight it since day one.

Patrick
__________________
Patrick Freivald -- Mentor
Team 1551
"The Grapes of Wrath"
Bausch & Lomb, PTC Corporation, and Naples High School

I write books, too!
  #26   Spotlight this post!  
Unread 07-01-2009, 20:12
rees2001 rees2001 is offline
Registered User
AKA: Rees
FRC #0340 (Greater Rochester Robotics)
Team Role: Teacher
 
Join Date: Jan 2002
Rookie Year: 2000
Location: Rochester NY
Posts: 802
rees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond reputerees2001 has a reputation beyond repute
Re: Underestimating the Trailer

Quote:
Originally Posted by pfreivald View Post
As a team that experiences a lot of ice and snow on a regular basis, we've been thinking about 'using the slipperiness' instead of somehow trying to fight it since day one.

Patrick

Wouldn't today be one of those ice & snow days?
  #27   Spotlight this post!  
Unread 07-01-2009, 22:04
Booksy Booksy is offline
Registered User
FRC #1244 (Viking Robotics)
Team Role: Programmer
 
Join Date: Apr 2008
Rookie Year: 2007
Location: Great White North
Posts: 97
Booksy will become famous soon enoughBooksy will become famous soon enough
Re: Underestimating the Trailer

What if you designed the robot to be mainly driven backwards?

Have the trailer be like the "skis". When you want to turn, just jackknife the trailer and drive straight. The wheels would that way aid in turning.

Or else maybe drive forward, turn backwards.

I honestly didn't think turning would be an issue... until we tried to turn today on linoleum. If you start off spinning you're fine, if you try to turn while driving straight, you better be prepared to wait. And that's without a trailer BTW.

I think the trailer could be used advantageously, if used properly. Just some testing is needed to figure out how that would work. Hopefully we'll have a trailer by Monday. I am thinking of taking some video of it and recommend other teams to do the same, that way we can all examine it and try and figure out how to drive with this thing.
__________________
My favorite CD quote ever(taken out of context of course):
Quote:
Originally Posted by ttldomination
water would be hard to build
  #28   Spotlight this post!  
Unread 07-01-2009, 22:27
Enigma's puzzle's Avatar
Enigma's puzzle Enigma's puzzle is offline
Strategery
AKA: Matt Brechting
FRC #2075 (Enigma)
Team Role: College Student
 
Join Date: Jan 2008
Rookie Year: 2006
Location: Sparta MI
Posts: 261
Enigma's puzzle is a splendid one to beholdEnigma's puzzle is a splendid one to beholdEnigma's puzzle is a splendid one to beholdEnigma's puzzle is a splendid one to beholdEnigma's puzzle is a splendid one to beholdEnigma's puzzle is a splendid one to beholdEnigma's puzzle is a splendid one to behold
Re: Underestimating the Trailer

If i planned on building to utilize the trailer for steering i would get practicing now.
  #29   Spotlight this post!  
Unread 07-01-2009, 23:02
silicon_ghoti's Avatar
silicon_ghoti silicon_ghoti is offline
AKA: I think I'm a freshman?
AKA: Luke
FRC #1425
Team Role: Alumni
 
Join Date: Jul 2006
Rookie Year: 2005
Location: Oregon
Posts: 44
silicon_ghoti will become famous soon enoughsilicon_ghoti will become famous soon enough
Re: Underestimating the Trailer

Quote:
Originally Posted by Petey View Post
I bet it'd be hard, but I'm pretty sure it's possible. You don't need a square chassis, all you need is a way to construct your back end in such a way that the sides of the hexagon abut the back end of your bot while the trailer tongue is pulled pretty far in while also observing the other rules about attaching easily and not hitting the walls before bumpers.
We were looking into that too, but our team came to the general consensus that FIRST was trying to articulate that the trailer hook-up was to be attached to the "outer-edge" created by the bumper polygon. For those curious about the bumper polygon it is shape created by the outermost points/corners of the robot. (Note, by definition polygons cannot have indentations, or in other words internal angles greater than 180 degrees.) But I would love for someone to prove us wrong.
__________________
What? You guys still opperate in only 2 dimensions?

This is a BEAR, it saves you.

Ghoti is pronounced "fish," ain't that sumthin'?
  #30   Spotlight this post!  
Unread 07-01-2009, 23:07
Team 2811's Avatar
Team 2811 Team 2811 is offline
WHAT DID YOU DO!? ..umm... whoops!
AKA: Ian Heffron
FRC #2811 (Stormbots)
Team Role: Electrical
 
Join Date: Jan 2009
Rookie Year: 2008
Location: Vancouver
Posts: 31
Team 2811 is on a distinguished road
Re: Underestimating the Trailer

I think that if you have enough speed when you are backing up the jack-knife problem won't be a problem since the wheels on the trailer have no more traction than the robot wheels so they will slip and slide even going sideways when jack-knifed. As long as you keep some speed when going either backwards or forwards you cann still keep going into a possible orientation spot.
Closed Thread


Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
The Trailer measurements Nadav Gross General Forum 16 06-01-2009 22:45
Attaching the Trailer Eiske Rules/Strategy 6 04-01-2009 22:33
Trailer Available for the Championship OZ_341 General Forum 0 23-03-2008 07:25
To Trailer or Not to Trailer? Carol General Forum 14 25-06-2006 18:14


All times are GMT -5. The time now is 04:32.

The Chief Delphi Forums are sponsored by Innovation First International, Inc.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright © Chief Delphi