I made a sphere bot using a hamster ball and a series of motors with weights on them. They are fast and fun. Would love to see how this thing conquers stairs.

anyone catch the obligatory automated dorm room door at 1:45 lol

also, i imagine what makes the ball manage obstacles so well is that it weighs a freaking tonne

@cyc4015
3rded

It uses gyroscopes to navigate the terrain so well.

@twistedsymphony: i live in the dorm at MIT where that automated door is! you can actually open/close it with an iPhone app. :)

Agree with others previous comments – it’s easy to make a sphemical bot with plain motors and drive it around. You can never get great steering, or more importantly stopping control with these designs though

This implementation really is excellent – the gyro seems to make it much more stable and controllable.

That’s me in the video, I’m glad you guys like it. I’d be happy to answer questions about it (or tanks or cannons or dorm room door actuators).

It certainly is. Making it hydraulic was more fun than just slapping an electric linear actuator on there. And it has the added benefit of being manually overridden and incredibly quiet in operation.

The gyroscopes work by storing huge amounts of angular momentum. They are used in way that makes them whats called control moment gyroscopes (http://en.wikipedia.org/wiki/Control_Moment_Gyroscope). They arent used for stability like in that example with harddrives. Their stored angular momentum is dispensed to create extra torque.

Two words:

AWESOME

@Greg: indeed, hydraulics rock :)

So I suppose (also from the pictures) there are two gyros spinning in the horizontal plane, I think you are only using them as a angular momentum storage, and then simply driving the ball against this momentum-heavy pendulum. (since attempting to tilt them will cause them to react by tilting left to right in opposite directions, which they cannot)

But how about simply attaching the gyros to the inside of the sphere on left to right gimbals, without using a pendulum, and then tilting them?
This should create forward torque I think, and would sound more like a CMG to me, no?
Not sure about turning though…

@Gizer20: Yes the robot still shifts center of mass for normal motion. The stored momentum gives the pendulum more than just gravity to push against to create torque. It uses both at the same time.

The shell is actually a polycarbonate gumball machine globe.

@Mic: The control system for this robot is significantly more complex than for the segway. I’m building a custom system with an IMU and encoders on all the parts. I’m also developing the dynamic equations of motion mathematically, which are all delightfully non-linear. After that I’ll be able to write the software to cancel out all the wacky movements.

@Greg: how is it that the gyro you have on the table is staying up? Is the lighting in the video obscuring something that I should be seeing or is it just a metal stick with the spinning ball parts on the end…and standing up on its own?

@ Dan Cardin

the stick with the ball has a gyro in the ball. when the gyro is spinning, it keeps itself positioned in relation to its original position and resists changes in yaw thereafter. once the gyro stops, the whole assembly falls.

theres more videos by gyroscopes.org that demonstrate some pretty cool gyroscopic precession.