Sway Less reaction-wheel balancing system

A physical inverted pendulum with embedded feedback control

Motion control
Electromechanical systems
Sensor integration

Sway Less prototype with labeled ESP32, IMU, SimpleFOC Mini motor driver, and flywheel — ESP32, IMU, and motor-driver integration.

CAD of the printed frame, reaction wheel, evenly spaced bolts, and protective bumpers — Frame and adjustable-inertia reaction wheel.

Overview

Our three-person team built Sway Less to explore balancing an inverted pendulum with a motor-driven reaction wheel. I worked on electronics, controller design, and mechanical assembly, connecting an ESP32, IMU, magnetic encoder, and BLDC motor driver into a closed-loop system.

We moved from Arduino to ESP32 and replaced the motor encoder to improve integration reliability. PID control with a wheel-speed penalty gave our best experimental response, but motor saturation and IMU noise limited sustained balance. The project connected a stable linear-model prediction with the constraints of real hardware.

Project video created and edited by me. Watch on YouTube ↗

Hardware and control

Electronics layout showing ESP32, MPU6050 IMU, AS5600 encoder, SimpleFOC Mini, BLDC gimbal motor, battery, and regulated power connections — Electronics layout: sensors, motor control, and power distribution.

Side view of the printed frame with the brushless gimbal motor labeled — Gimbal motor within the printed frame.

Feedback block diagram showing angle PID control, motor gain, inverted-pendulum plant, and reaction-wheel velocity penalty — Angle feedback with a reaction-wheel speed penalty.

Bode magnitude and phase plots from the team’s linear control model — Frequency response from the linear model.

Root-locus plot for the modeled PID controller with wheel velocity penalty — Modeled PID control with a velocity penalty.

Simulated pendulum-angle recovery from a two-degree initial offset toward zero over three seconds — Simulated recovery from a 2° offset; not measured hardware performance.