Electric Unicycle

Overview

An electric unicycle (EUC) is a self-balancing personal vehicle built around a single in-wheel motor. The rider stands on two folding pedals straddling the wheel and steers by leaning. There are no handlebars and no throttle: speed and direction come entirely from body weight shifts, which the machine reads and answers by driving the wheel. The whole drivetrain, battery, and electronics pack into a Shell & Housing no wider than the tire, so the vehicle is compact enough to carry into a building once the Telescoping Handle is extended and the unit is wheeled like luggage.

This configuration runs an 84 V pack and a direct-drive hub motor, giving a 50 km/h top speed and 60–75 km of range. The pedals fold flush against the shell for transport, and TPU bumpers protect the body from tip-overs.

How it works

Balance is the core trick. A 6-axis IMU Module measures the wheel's pitch angle and rotation rate hundreds of times a second. The Control Board runs a closed-loop controller: when the rider leans forward, the frame pitches, the IMU reports the tilt, and the controller commands motor torque to drive the wheel under the rider's center of mass. The faster the lean, the harder it drives. Leaning back reverses the torque and brakes. Because the loop only ever tries to keep the wheel beneath the rider, accelerating, cruising, and stopping are all the same control action expressed at different lean angles.

Torque reaches the road through the Hub Motor, an outer-rotor BLDC whose magnets ring the inside of the wheel rim. Hall sensors track rotor position so the inverter can commute the three phases, switching the high pack current through an IGBT stage with a MOSFET gate path. Energy comes from the Battery Pack, a 20S3P lithium pack whose BMS balances cells and clamps charge and discharge limits; at speed the same path runs in reverse, feeding regenerative braking energy back into the cells.

Two safety interlocks gate the drive. Each Foldable Pedal carries a presence sensor, so the motor refuses to spin unless a rider is standing on the pedals. As the unit approaches its speed ceiling it performs a tilt-back, pitching the pedals up to physically push the rider to ease off, and sounds a warning through the kit speaker. Configuration, speed limits, and firmware updates are handled wirelessly through the onboard Bluetooth module and the rider's phone app.