3D-Printed Self-Balancing Robot Brings Control Theory To Life

December 27, 2022 by Robin Kearey 8 Comments

Stabilizing an inverted pendulum is a classic problem in control theory, and if you’ve ever taken a control systems class you might remember seeing pages full of differential equations and bode diagrams just to describe its basic operation. Although this might make such a system seem terribly complicated, actually implementing all of that theory doesn’t have to be difficult at all, as [Limenitis Reducta] demonstrates in his latest project. All you need is a 3D printer, some basic electronic skills and knowledge of Python.

The components needed are a body, two wheels, motors to drive those wheels and some electronics. [Limenitis] demonstrates the design process in the video below (in Turkish, with English subtitles available) in which he draws the entire system in Fusion 360 and then proceeds to manufacture it. The body and wheels are 3D-printed, with rubber bands providing some traction to the wheels which would otherwise have difficulty on slippery surfaces.

A PCB driving two stepper motors — The PCB has just a few components, with most of the complexity handled by plug-in modules.

Two stepper motors drive the wheels, controlled by a DRV8825 motor driver, while an MPU-9250 accelerometer and gyroscope unit measures the angle and acceleration of the system. The loop is closed by a Raspberry Pi Pico that implements a PID controller: another control theory classic, in which the proportional, integral and derivative parameters are tuned to adapt the control loop to the physical system in question. External inputs can be provided through a Bluetooth connection, which makes it possible to control the robot from a PC or smartphone and guide it around your living room.

All design files and software are available on [Limenitis]’s GitHub page, and make for an excellent starting point if you want to put some of that control theory into practice. Self-balancing robots are a favourite among robotics hackers, so there’s no shortage of examples if you need some more inspiration before making your own: you can build them from off-the-shelf parts, from bits of wood, or even from a solderless breadboard.

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Self balancing wheeled robot with auto-righting arms lofted high

A Self Righting Balancing Robot Configured The Easy Way

December 13, 2021 by Dave Rowntree 2 Comments

Norwegian electronics hacker [Hans Jørgen] aka [time expander] on YouTube, has a clear interest in robotics, and for his latest effort, decided that it was time to build a custom controller platform. Since [Hans] had a pile of Dynamixel servo motors lying around to test it with, a good first project for the platform was a simple self-balancing wheeled robot. (Video, embedded below)

We say ‘simple’ but that isn’t really the case, as there is a fair bit going on to get this to work. The first problem, is sensing, which was quickly solved with the excellent BMO055 IMU chip. Next, what to do when it falls over? Simply adding some servo-controlled arms, allowed the robot to flip itself back upright. Control is covered with a ESP32-WROOM-32D module from our friends at Espressif, which enables remote firmware uploading over the air (OTA update) as well as parameter tuning. In order to implement the latter, [Hans] chose to use bonjour/mDNS which is an implementation of zero-configuration networking. This gets the ESP32 onto the WiFi, but it isn’t immediately obvious how to connect to it, without a little digging around. To simply connection, [Hans] implemented a dynamic QR code via the connected OLED. This is just one of the those tiny 0.96″ displays that you see touted all over our corners of the internet.

Simply by scanning the QR code with any compatible device to hand brings up a simple configuration web page, allowing one to tweak the PID controller parameters, and get that balancing robot into check. Great stuff!

The PCB was designed in Eagle, firmware for the ESP32 is available, 3D models for the plastic are designed with fusion 360, and [Hans] is even currently working on some preliminary Alexa integration. What a fun project!

All the above, albeit an early cut (look out for bugs!) is available on the project GitHub for your viewing pleasure.

We’re no stranger to self-balancing 3D-printed bots, whilst you’re here, why not checkout A problematic Self-Balancing Sonic the Hedgehog? If wheeled bots aren’t your cup-of-tea, there’s a not-at-all freaky one-legged bouncing bot that may be of interest.

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Hackaday’s Omaha Mini Maker Faire Roundup

September 26, 2015 by Kristina Panos 3 Comments

The 2nd annual Omaha Mini Maker Faire wasn’t our first rodeo, but it was nonetheless a bit surprising . Before we even made it inside to pay our admission to the Omaha Children’s Museum, I took the opportunity to pet a Transylvanian Naked Neck chicken at one of the outdoor booths. The amiable fowl lives at City Sprouts, an Omaha community farming collective in its 20th year of operation. There seemed to be a theme of bootstrappy sustainability among the makers this year, and that’s great to see.

Just a few feet away sat a mustard-colored 1975 Chevy pickup with a food garden growing in its bed. This is Omaha’s truck farm, an initiative that seeks to educate the city’s kids in the ways of eating locally and growing food at home. On a carnivorous note, [Chad] from Cure Cooking showed my companion and me the correct way to dry-cure meats using time-honored methods.

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Two-Wheel Balancing Robot Revived From The Dead

February 7, 2014 by James Hobson 1 Comment

Capture

[Jouni] built a pretty nice little two-wheeled robot a while back — but he never got it working quite right. Taking inspiration and a bit of opensource code from another hacker featured here, he’s finished the bot, and it works great!

After seeing [Jose’s] 3D printed Air Hockey bot, he poked around the creator’s blog and discovered the B-Robot, a 3D printed, two-wheeled, stepper driven, balancing robot. As it turned out, it was incredibly similar to a robot [Jouni] had made himself previously!

[Jouni’s] robot features two NEMA-17 steppers, a 12v 2200mAh battery pack, an Arduino Pro Mini, a MPU6050 gyro and a FrSky receiver. Lucky for him, [Jose’s] B-Robot made use of the same steppers and gyro! Using some of [Jose’s] code from his GitHub, [Jouni] was able to bring new life into his little robot!

We’ve included videos of both the original project, and [Jouni’s] version. Aren’t opensource projects awesome?

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Your Robot Stand-in Has Arrived

March 28, 2011 by Mike Szczys 15 Comments

Meet TIPI, the Telepresence Interface by Pendulum Inversion. TIPI is something of a surrogate, giving physical presence to telecommuters by balancing an LCD screen and camera atop its six foot frame. The user has full control of the robot’s movement, with their own camera image shown on the display so that others interacting with the bot will with whom they are conversing.

A pair of 12.5″ wheels connec to DC motors via a gear box with a 37:1 ratio. These specs are necessary to recover from a sudden 20 degree loss of equilibrium, quite impressive for a bot of this stature. An Orangutan SVP board monitors a two-axis accelerometer and a gyroscope for accurate positioning data. This board automatically keeps balance, while taking user commands from a second control, a Beagle Board. The Beagle Board handles the communications, including sending and receiving the video signals, and delivering incoming position control data to the Orangutan. Separating the two systems guards against a screen-shattering fall by making sure the hardware likely to face slow-down or lockup is physically separate from that responsible for balance.

Check out the video clip after the brake to see some balancing goodness. It shouldn’t be hard to build your own version for much less than the $15k price tag enjoyed by some commercial versions.

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Balancing One Wheel Scooter

March 8, 2007 by Will O'Brien 53 Comments

Fresh off the tip line, [Ben] sent in his one wheeled balancing scooter. It’s a nice simple design – I just might have to build one myself. The steel frame surrounds a pair of 12V 12Ah SLA batteries, a 400w 24v DC motor, one of the ever handy OSMC motor controllers, rate gyro, accelerometer and a PIC 16F876A. I love the entire concept! (For some reason, I’m thinking it needs a brake light on the rear…

Check out the video after the cut. He walks through the hardware at the end.

By the way, Eliot and I’ll be at Shmoocon in a couple of weeks. We won’t have boards from the Design Challenge yet, but we should have something to give away to people who find us there.

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