View Single Post
  #2   Spotlight this post!  
Unread 03-02-2003, 16:00
Chris Hibner's Avatar Unsung FIRST Hero
Chris Hibner Chris Hibner is offline
Eschewing Obfuscation Since 1990
AKA: Lars Kamen's Roadie
FRC #0051 (Wings of Fire)
Team Role: Engineer
 
Join Date: May 2001
Rookie Year: 1997
Location: Canton, MI
Posts: 1,488
Chris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond reputeChris Hibner has a reputation beyond repute
Making the robot turn

Here is what I would suggest (none of these options are easy, so I would get to work ASAP to make the changes):

1) Go to a much lower gear ratio. This still might not work, though, and your robot will still most likely bounce a lot when you turn.

2) Change the wheel footprint. Take a look at where the wheels contact the ground. I'd be willing to bet that your track width is smaller than your wheel base (track width is the left-to-right measurement between the wheels; wheel base is the front-to-back measurement of where the wheels touch the ground). You can do a quick static analysis to show that if your track width is smaller than your wheel base, you will have a lot of trouble turning.

3) Change the center of gravity. It is possible to make your robot turn by moving the center of gravity to either the fore or aft limit. This has an undesired side effect of making your robot easier to be tipped over in one direction.

4) Change to a different type of wheel that allows side slippage (like holonomic wheels).

5) Remove one set of wheel and replace with casters. This is probably the easiest thing to do, but just realize that you will probably lose about half of your pushing force.

If you need anything (like to know why changing the wheel-base to track-width ratio makes it easier to turn), either PM me or send me an e-mail.

-Chris