Omni wheels normally contain a number of rollers arranged on their circumference, allowing them to slide left and right and perform various tricks when combined with others. The rollers on UCLA researchers Junjie Shen and Dennis Hong’s OmBURo, however, are quite different in that they are actually powered, enabling a single wheel to accomplish some impressive feats on its own.

These powered rollers give OmBURo the ability to move in both longitudinal and lateral directions simultaneously, balancing as a dual-axis wheeled inverted pendulum. 

Control is accomplished via an Arduino Mega along with an IMU and encoders for its two servo motors —one tasked with driving the wheel backwards and forwards, the second for actuating the rollers laterally via helical gears and a flexible shaft. 

As seen in the video below, the robot can follow different paths via remote control, and even balance on an inclined plane. More informaton on the impressive build is available in the Shen and Hong’s research paper here.

A mobility mechanism for robots to be used in tight spaces shared with people requires it to have a small footprint, to move omnidirectionally, as well as to be highly maneuverable. However, currently there exist few such mobility mechanisms that satisfy all these conditions well. Here we introduce Omnidirectional Balancing Unicycle Robot (OmBURo), a novel unicycle robot with active omnidirectional wheel. The effect is that the unicycle robot can drive in both longitudinal and lateral directions simultaneously. Thus, it can dynamically balance itself based on the principle of dual-axis wheeled inverted pendulum. This letter discloses the early development of this novel unicycle robot involving the overall design, modeling, and control, as well as presents some preliminary results including station keeping and path following. With its very compact structure and agile mobility, it might be the ideal locomotion mechanism for robots to be used in human environments in the future.

Retired maker “lingb” created an omni-bot, with four wheels that allow sliding motion in the X/Y plane courtesy of their perpendicular rollers. While that alone would have been a fun build, he also attached a pen, along with a servo-based lifting mechanism, turning this robot into a free-range plotter!

The device is controlled by an Arduino Uno and Bluetooth module, and takes movement commands via a linked smartphone or tablet. Four 28BYJ-48 stepper motors with ULN2003 drivers move each wheel, though outputs are shared between opposite motors to save on I/O. 

This means that rotating the robot isn’t possible, but as shown in the video below, this isn’t needed to plot straight and curved lines with good accuracy.

Omni wheels are devices that look like wheels with extra rollers positioned along their circumference. This allows robots to move forwards and backwards, as well as slide and spin depending on how the wheels are powered. Maker Jeremy S. Cook decided to create his own version, and after some consideration and careful design work, constructed a cylindrical frame out of MDF and PLA.

The Roomba-like unit features an Arduino Nano, which controls four NEMA 17 stepper motors via Easy Driver boards, while a Bluetooth module enables smartphone operation. Once a few intermittent motion issues are worked out, the stepper motors should provide precise positioning for further robotics experimentation.

Code for the build can be found here.