Re: sphere bot
 

Hey, just throwing you this simple idea.

I currently have one of this sitting in my closet:

The Motor Ball

This RC ball just has 2 half-sphere shaped wheels. The black bands are like giant rubber bands. These wheels are also hollow and connected by one bolt each. As a matter of fact you have to take off one wheel to change the battery.

The battery and motors are mounted very low to keep a low center of gravity similar to the weight on a Segway.

The black antenna has a wheel on the end of it so when you "hit the gas" it keeps the whole motor mechanism from spinning around inside the ball. So in other words it is connected to the motorized mechanism and when you make it move forward the wheel hits the ground thus making it move forward.

If you made your wheel with a very low center of gravity you may not need this wheel/antenna combination.

This RC can do 360's and can pretty much do anything, however, it is very hard to control.

Re: sphere bot
 

While nice, the problem is that you can't move any direction, like sidways, without turning. If I want to build a ball bot, I want it to be able to turn left, right, forward, and back without having to turn.

Re: sphere bot
 

How about this idea then?

I just thought this up.

Do all the of the controlling from inside the ball rather than outside.

Of course you are going to have to make this a two piece bolt together on the outside though.

The 2 upright omni wheels shift the weight forward or backward.
The 2 sideways onmi wheels shift the weight left or right.

This combination thus moves this ball in any direction.

The problem with any ball is once you get it moving how do you stop without the ball rolling???

(Just realized you can probably eliminate the sideways omni wheels as the forward moving omnis will just spin them on a dime, well hopefully anyway.)

I think this idea would work; I really have not put much thought into it.

Re: sphere bot
 

team222badbrad had the same idea.


I had pretty much the same idea. Use two sphere halves, and mount them so they can spin freely of a center part holding your electronics and motors. Use an adjustable ratchet type setup to move the sphere halves, so that when the motors engage they move the sphere halves, but if you slow down, the ratchet won't let the sphere take off spinning with your motors and everything else. stopping is still to be determined, except just letting it roll. But if your center of gravity is low enough, the center portion of your bot will stay pretty much level, and you can mount a small arm to it. Wheely bars just in case.

Re: sphere bot
 

THat is very similer to what Squirrel Rock and I thout up. Onlywe had many more omniwheels for stability. all you need to do is to keep the weight low and turn the ball on the outside.

Re: sphere bot
 

I kind of wish I had one of these. Well, on second thought I really have no idea what I would do with it. It sure is interesting to watch to say the least.

If someone here can actually duplicate that, I'll eat my hat.

Re: sphere bot
 

Oh wow you guys brought up my dead thread. oh well heres what i have to say.

Me and a few of my friends actually designed all of the stuff for it. With an arm too.. believe it or not. Heres how:

The sphere was basically a robot with 4 wheels at 90 degrees to each other, which rests inside the sphere outer frame made of fiberglass. The wheels rested exactly on the "x" and "y" axis, exactly halfway up the sphere. This means that you can go sideways, and any other direction, without using omniwheels at all. The sphere was designed so it comes apart in halfs with the removal of 8 bolts, and had two large 3" holes on opposite sides. As for the arm, it was an arm similar to 254's arm last year, which extends out of one of these holes. Yes we would have sensors to align the hole with the arm. Retract the arm and start roling again. To get the most effective "roll power", we put all our weight at the bottom of the robot, calculated that it would give us a 12 inch lever arm.

Warning: sphere bots involve lots of physics calculations.
We had to use mad physics skills to calculate the maximum acceleration the sphere would undergo until the "robot" inside it would flip over. painful

on a side note, to insure that your sphere bot does not die when the inner robot actually does flip, ball castors are used to keep the robot constantly centered. yes. enought talk i go to sleep now.

regionals tomorrow!!!

:D