🧊 Self-Balancing Cube

Balance a 3D-printed cube on a single corner using an ESP32 and reaction wheels.

📋 Overview

This is a marvel of modern control theory. By rapidly spinning brushless motors equipped with heavy flywheels (reaction wheels), the cube generates counter-torque to perfectly balance on its vertex.

What you'll learn: Matrix math for 3D state estimation, LQR (Linear Quadratic Regulator) or cascaded PID control, and Field Oriented Control (FOC) for brushless motors.

Estimated time: 15+ hours. Difficulty: ⭐⭐⭐⭐⭐ Expert.

🧩 Components Needed

Component	Specification	Qty	Notes
ESP32	Dual Core	1	Needed for fast matrix math
Brushless Motors	Gimbal motors	3	Low KV
SimpleFOC Mini	Motor Driver	3
MPU6050	IMU	1
Brass Flywheels	Heavy	3	For momentum

📖 Step-by-Step Tutorial

Mechanical Symmetry

The center of mass must be perfectly aligned over the balancing corner. Print the frame with high infill.

IMU Calibration

The IMU must be perfectly calibrated. Even a 0.5-degree error in the accelerometer offset will cause the cube to accelerate and eventually fall.

FOC Tuning

Use the SimpleFOC library to tune the PID for the motor velocities. The motors must respond instantly without jitter.

State Matrices

Implement the balancing algorithm. It takes the pitch and roll from the IMU and calculates the required torque for each of the 3 motors.

💡

Braking a fast-spinning brushless motor dumps energy back into the battery. Ensure your battery and circuitry can handle regenerative braking spikes.

💻 Code / Configuration

balancing_cube.ino

INO

// Balancing Cube FOC setup (Snippet)
#include <SimpleFOC.h>

BLDCMotor motor1 = BLDCMotor(7);
BLDCDriver3PWM driver1 = BLDCDriver3PWM(25, 26, 27, 14);
MagneticSensorI2C sensor1 = MagneticSensorI2C(AS5600_I2C);

void setup() {
  sensor1.init();
  motor1.linkSensor(&sensor1);
  
  driver1.voltage_power_supply = 12;
  driver1.init();
  motor1.linkDriver(&driver1);
  
  motor1.voltage_sensor_align = 3;
  motor1.controller = MotionControlType::velocity;
  
  motor1.init();
  motor1.initFOC();
}

void loop() {
  motor1.loopFOC();
  // Target velocity calculated by main balancing loop

⭐Reviews & Ratings

—

0 reviews

5★

4★

3★

2★

1★

...

Loading reviews...