This Monowheel Robotic By no means Topples

A monowheel is a kind of auto that rides on a single wheel. It’s possible you’ll suppose that sounds loads like a unicycle or a Onewheel-style electrical skateboard, however the distinguishing function of a monowheel is its huge diameter. A conventional monowheel automobile carries its rider throughout the center, the place the hub could be. Within the case of smaller robots, the motor and all the digital elements sit throughout the circle of the rim. However like a unicycle, it’s onerous to maintain a monowheel upright whereas shifting slowly or standing nonetheless. To skirt that challenge, James Bruton constructed a mechanically steady monowheel robotic.

Calling this a “monowheel” is a little bit of a cheat, as a result of it technically has two wheels — they’re simply very shut collectively. The usage of two wheels comes with benefits. First, it lets the robotic steadiness in place with out tipping to both facet. Second, it makes steering easy. Like a tank, this robotic has differential drive: spin one wheel quicker than the opposite and it’ll flip. It may possibly even rotate in place if the wheels spin in reverse instructions.

However the large innovation right here is the kind of wheels that Bruton selected. Every of these is a pedrail wheel, which is an odd contraption with an entire bunch of sliding legs in a radial association with pivoting toes. It rotates like a wheel, however retains no less than a number of toes in touch with the bottom at any given time. Not solely does that assist it traverse sure obstacles, like steps, however it additionally means the pedrail wheel can stay stationary with out rolling forwards or backwards.

Bruton 3D-printed virtually all the mechanical elements for this robotic, together with the legs and toes. The one elements that weren’t 3D-printed have been the fasteners and bearings. Due to the distinctive drive system, this robotic’s electronics are fairly easy — no IMU (inertial measurement unit), gyroscope, or accelerometer obligatory. There are two DC motors that spin the wheels and a Teensy 3.2 improvement board controls these. It receives instructions from Bruton’s common distant through OrangeRX DSM transceivers.