May 25, 2017, 10:21:55 am
Welcome, Guest. Please login or register.

Author Topic: designing a 3 wheeled battle bot  (Read 709 times)

65fastbackmaniac

  • Roboteer
  • *
  • Posts: 21
    • View Profile
designing a 3 wheeled battle bot
« on: September 20, 2016, 11:52:50 pm »
I am designing a 3lb bot. My idea is basically a Oreo made of two saw blades (not actual saw blades but I will design the body to resemble them) from watching competitions and events I know it is possible to make a bot the drives on 3 wheels put is there a guide or could someone point me in the right direction. I have heard mention of gyro but would even know which one to look at. My design is based on 3 wheels on equal axis around a circle but I haven't figured out how to make the whole driving work. I'm trying to run it on Spark motors 33.3:1 with 3 inch wheels.

Coboxite

  • Roboteer
  • **
  • Posts: 97
  • Made with real lemons
    • View Profile
Re: designing a 3 wheeled battle bot
« Reply #1 on: September 21, 2016, 01:33:16 am »
You need an omni mixer. The mixer works with your ESCs and radio to get three planes of movement(Forward-Backward, Left-Right, Spin).


The gyro you're looking for is a peizo gyro. You'll want a heading hold gyro(Or a Tail-Lock gyro, same thing). Its purpose is to auto correct for unwanted control deviations. For two wheeled bots, this means a straight, true line. For four wheeled bots, its a smooth turn. I don't know enough about omni wheel driven bots, but I'd imagine its somewhere in between(Anybody with more experience with omni wheels please fill in). If your bot is invertable, you'll want a method of turning the gyro off remotely. Gyros when flipped upside down get grumpy and get stuck in a infinite feedback loop(ie; an uncontrolled spin that wont stop until the gyro is shut off). Higher end gyros have the switch as a feature, but if your gyro doesn't have it, you can just get a dedicated switch.


One last thing, you might want to look into dedicated omni wheels. Regular wheels would cause huge friction losses if used in the configuration you're talking about. Just keep in mind that they're a bit heavy, and they're fragile. Keep them internal and be prepared to replace them when they shatter.

drsmall

  • Roboteer
  • *
  • Posts: 4
    • View Profile
Re: designing a 3 wheeled battle bot
« Reply #2 on: October 04, 2016, 03:37:17 pm »
Yes more omni-wheeld bots! I'm building one too. I'm using these http://www.robotshop.com/en/58mm-plastic-omni-wheel-lego-nxt-servo.html for wheels. These wheels may help you. I thought they were a decent balance between durability and weight. They also slide right onto a 4mm shaft. Since you're building a spinner, it sounds like you'll already have your wheels protected by armor, which will be essential.

65fastbackmaniac

  • Roboteer
  • *
  • Posts: 21
    • View Profile
Re: designing a 3 wheeled battle bot
« Reply #3 on: March 27, 2017, 09:19:31 pm »
Actually I finally got the bot driving then did a complete redesign but I'm still going with a Omni driving system and spinner bot. Unfortunately I'm trying to build three combat bots and a personal bot all at once so I'm hoping to get it so I can take it to Dragon Con which is the main competition I go to.