Self balancing robot uses cascading PID algorithms

At this point we’re beginning to think that building a self-balancing robot is one of the rights of passage alongside blinking some LEDs and writing Hello World on an LCD screen. We’re not saying it’s easy to pull off a build like this one. But the project makes you learn a lot about a wide range of topics, and really pushes your skills to the next level. This latest offering comes from [Sebastian Nilsson]. He used three different microcontrollers to get the two-wheeler to stand on its own.

He used our favorite quick-fabrication materials of threaded rod and acrylic. The body is much taller than what we’re used to seeing and to help guard against the inevitable fall he used some foam packing material to protect the top level. Three different Arduino boards are working together. One monitors the speed and direction of each wheel. Another monitors the IMU board for position and motion feedback, and the final board combines data from the others and takes care of the balancing. Two PID algorithms provide predictive correction, first by analyzing the wheel motion, then feeding that data into the second which uses the IMU feedback. It balances very well, and can even be jostled without falling. See for yourself in the clip after the break.

[Read more...]

Self balancer does it differently than we’re used to seeing

This self balancing robot still uses just two wheels, but it’s balancing very differently than we’re used to seeing. Where most of the projects use a form factor that’s similar to a Segway, this works just like a bicycle. But it doesn’t need to keep the front and rear wheels spinning to stay upright. In fact, the video after the break shows it balancing perfectly while at a complete standstill. [Aoki2001's] creation isn’t stuck in one place. He included distance sensors on the front and back which are used to move the bike as if by repulsion.

The large wheel where the rider would be is what makes sure the vehicle doesn’t topple over. It acts as an inverted pendulum, pushing against the large wheel’s inertia by rotating the motor to which it is attached. The same concept was seen back in march on a full-sized bike. But why use two wheels when you only need one? His unicycle version can also be seen embedded after the break.

It’s worth looking at [Aoki's] other YouTube offerings too. He’s got a small robot which balances on top of a ball. It’s the desk-sized version of this hack.

[Read more...]

Self-balancing unicycle only for those with good balance

The only problem with this self-balancing unicycle is it’s inability to balance itself. You see, it automatically balances along the axis that is parallel to the line of travel. But since there’s only one wheel the rider is responsible for balancing perpendicular to travel. This is really not too much different from a bicycle; balancing while in motion is pretty simple. Only when you slow down or stop are you in trouble.

[Stephen Boyer] built the vehicle and uses it for most of his travel around the MIT campus. It carries a pair of 12V batteries that pack enough punch to travel five miles between charges. A 5DOF board senses motion and orientation, with an ATmega328 microcontroller calculating the corrections necessary to keep the rider upright.

The demo video after the break never really gives you good look at the thing, but it’s enough to prove that it does indeed work very well. We’re also glad to see that [Stephen] is using a kill-switch while riding.

If you’re aching for more electric unicycle video check out this other project too. [Read more...]

Domo Kun robot achieves balance sans gyroscope

Every time it tips over, the FSM kills a kitten

Most self-balancing robots use some sort of circuitry like gyroscopes or accelerometers to keep them upright. Some bots however, can achieve nearly the same effect by far less complicated means.

Meet the Domo Kun wobbly bot, created by [Chein]. The robot is essentially a pendulum, where the pivot point is even with the wheel axle. The base of the robot is loaded with batteries, motors, and weights, all of which keep the robot relatively steady while zooming about the room. A light balsa wood frame was fitted to the top of the metal chassis, and a thin cardboard Domo Kun shell was mounted on top of that. The robot is driven using the remote control circuitry that he stripped from a toy car. He also mentions that the positioning of the batteries and weights is key to getting the robot to balance and roll properly – something that took several attempts to get just right.

Now if he could only program it to autonomously chase kittens…

Be sure to check out the pair of videos we have below of the robot chassis in testing as well as the final product.

[via HackedGadgets]

[Read more...]

Self-balancing robot keeps things on the straight and narrow

self_balancing_robot

[James] designed a digital controller in MatLab, but he really wanted to see if it would work in a real-world application. To test out his linear quadratic regulator design, he decided to build a self-balancing robot. His goal was to built a robot that can keep its balance even when external forces are applied, all while staying in the same place.

Balancing on a pair of wheels is not all that simple, so his LQR controller allows him to weight the bot’s priorities towards keeping balance, focusing on returning to its starting position once equilibrium has been achieved. The results are pretty impressive as you can see in the videos below.  The robot is easily able to attain its balance once powered on, and it has no problem remaining stable even when pushed or when objects are placed on top of it.

[James] has plans for several enhancements in the near future, including remote control via Xbee modules as well as autonomous navigation utilizing sonar or possibly a camera. We’d totally love to see it sporting a Kinect sensor in a future revision, but that’s just us!

Keep reading for a couple of demo videos he put together.

[Thanks, Nicholas]

[Read more...]