Building a Self-Balancing Robot Made Easy

Not only has [Joop Brokking] built an easy to make balancing robot but he’s produced an excellent set of plans and software for anyone else who wants to make one too. Self-balancers are a milestone in your robot building life. They stand on two-wheels, using a PID control loop to actuate the two motors using data from some type of Inertial Measurement Unit (IMU). It sounds simple, but when starting from scratch there’s a lot of choices to be made and a lot of traps to fall into. [Joop’s] video explains the basic principles and covers the reasons he’s done things the way he has — all the advice you’d be looking for when building one of your own.

He chose steppers over cheaper DC motors because this delivers precision and avoids issues when the battery voltage drops. His software includes a program for getting a calibration value for the IMU. He also shows how to set the drive current for the stepper controllers. And he does all this clearly, and at a pace that’s neither too fast, nor too slow. His video is definitely worth checking out below.

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Starfish Cat, Bowling Ball Bot, and Stargate all Claim Prizes

We saw a huge outpouring of builds for the the Hackaday Sci-Fi Contest and it’s now time to reveal the winners. With 84 great themed projects submitted, the judges had a tough task to pull out the most impressive both in terms of creativity and execution.

Here are our four winners. Two come from the Stargate universe. One is a cuddly yet horrifying character of unknown origin but unarguably Sci-Fi. The other is the best use of a bowling ball we’ve seen so far.

Grand Prize

The grand prize goes to [Jerome Kelty] with Animatronic Stargate Helmet. [Jerome] has built a replica prop that looks like it just came out of a Hollywood shop. It’s almost a shame that this helmet won’t be worn on film – though it certainly could be. If you remember the film and the television show, these helmets have quite a bit of articulation. The head can pan and tilt. The eyes glow, as well as have irises which expand and contract. The “wings” also open and close in a particular way.

[Jerome] built the mechanics for this helmet. He used radio control servos to move the head, with the help of some hardware from ServoCity. Most of the metalwork was built in his own shop. Everything is controlled from a standard R/C transmitter, much like the original show. [Jerome] is taking home a Rigol DS1054Z 4 Channel 50 MHz scope.

First Prize

First prize goes to [Christine] with
Starfish Cat: Your Lovecraftian Furby-like Friend. Starfish Cat is one of those odd projects that finds itself right on the edge of the uncanny valley. We are equal parts intrigued and creeped out by this… thing. The bottom is all starfish, with a rubber base poured into a 3D printed mold. The top though, is more cat-like, with soft fur and ears. 5 claws hide under the fur, ready to grab you.

Starfish Cat detects body heat with 5 bottom mounted PIR sensors. The sensors are read by the particle photon which acts as its brain. When heat is detected, Starfish Cat activates its claws, and also blows or sucks air through its… uh… mouth hole.  [Christine] is taking home a Monoprice Maker Select Mini 3D printer.

Click past the break to see the rest of the winners

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Robot Leaps Uncanny Valley on Backward Knees

We’ve covered a ton of Boston Dynamics robots but this is the second one in a row that has shown a departure from what a lot of people’s notion of an ‘advanced’ robot should look like. It’s a cellphone camera clip of a video played at a conference, but at least it isn’t vertical video — kudos to [juvertson]. At about 3:40 seconds into the video you get a good look “Handle” at a four-limbed robot with backwards joints and wheel.

This design makes a lot of sense and it’s good to see Boston Dynamics thinking about unique robot kinematics alongside the realities of motion. The result is something that appears neither human nor animal — it’s definitely not natural. Despite the presenter’s assertion that this will be nightmare-inducing, we think it’s the opposite, since it doesn’t tweak that string in your brain that cries “predator”.

Obviously this is what we’d call a self-balancer. But two-wheels-plus-rigid-frame it is not. The articulated lower limbs allow it to shift its mass over the wheels. The upper limbs play their part in balancing, at one point acting in the same way a figure skater’s arms would during a spin. And its dexterity in hopping over an obstacle is only made better by [juvertson’s] commentary. This is a really good balance between purely wheeled and purely humanoid designs and a nice addition to the evolution of robotics.

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Resistance is Futile: Balancing Cubes Are Taking Over!

It’s been a while since we’ve seen a balancing cube, but as different companies and universities start making them, we’re excited to see how they continue to develop. This one doesn’t really have a catchy name, but its designers [Erik Bjerke] and [Björn Pehrsson] call it a Nonlinear Mechatronic Cube.

Very similar to Cubli — the first self-balancing cube inside of balancing cubewe remember seeing — this cube can jump up from surfaces, “walk” and balance in any orientation.

The system features an IMU to determine orientation, three gyros powered by beefy 70W motors, three bicycle brakes powered by servo motors, and a microprocessor to control it all.

The way it balances is quite obvious with the gyros, but the ability to jump comes from the rapid breaking of the “reaction wheels”, allowing for a sudden impulse of force that is powerful enough to reorient the entire cube. The interesting part is how both systems are actually controlled individually with separate control systems.

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Hackaday Prize Semifinalist: Balancing Humanoid Robots

A few years after we all tire of our remote control BB-8 droids we’ll all have personal human robots designed specifically for human interaction. We’re not there yet, but [Poh Hou Shun] out of Singapore is working on a robot like this for the Hackaday Prize. It’s called OSCAR, the Omni Service Cooperative Assistance Robot.

As with any robotics platform, the use case defines the drive system; you’ll want knobby tires or treads if you’re building a sumo bot, and a strange articulating suspension if you’re driving over alien terrain. OSCAR is built for humans, and this means a humanoid chassis is required. Legs, however, aren’t. Instead of a complex system of motors and joints, OSCAR is balancing on a ball. No, it won’t go up stairs, but neither will many other robots either.

So far, [Poh Hou Shun] has built the basics of a drive system, and it’s surprisingly similar to the BB-8 droids we’re still not tired of yet. On the bottom is a large ball held in place with a spring-loaded retainer. On top of this are three stepper motors, each holding an omni wheel. It will work, there’s no doubt about that, and with the right humanoid chassis, some sensors, and a lot of software, this could be a very cool social robot.

The 2015 Hackaday Prize is sponsored by: