Arduino Simple Field Oriented Control (FOC) library

We live in very exciting times 😃! BLDC motors are entering the hobby community more and more and many great projects have already emerged leveraging their far superior dynamics and power capabilities. BLDC motors have numerous advantages over regular DC motors but they have one big disadvantage, the complexity of control. Even though it has become relatively easy to design and manufacture PCBs and create our own hardware solutions for driving BLDC motors the proper low-cost solutions are yet to come. One of the reasons for this is the apparent complexity of writing the BLDC driving algorithms, Field oriented control (FOC) being an example of one of the most efficient ones. The solutions that can be found on-line are almost exclusively very specific for certain hardware configuration and the microcontroller architecture used. Additionally, most of the efforts at this moment are still channeled towards the high-power applications of the BLDC motors and proper low-cost and low-power FOC supporting boards are very hard to find today and even may not exist.
Therefore this is an attempt to:

• 🎯 Demystify FOC algorithm and make a robust but simple Arduino library: Arduino SimpleFOClibrary
  • Support as many motor + sensor + driver + mcu combinations out there
• 🎯 Develop a modular FOC supporting BLDC driver boards:
  • NEW 📢: Minimalistic BLDC driver (<3Amps) : SimpleFOCMini .
  • Low-power gimbal driver (<5Amps) : Arduino SimpleFOCShield.
  • Medium-power BLDC driver (<30Amps): Arduino SimpleFOCPowerShield .
  • See also @byDagor's fully-integrated ESP32 based board: Dagor Brushless Controller

NEW RELEASE 📢: SimpleFOClibrary v2.2.2 see release

• GenericCurrentSense bugfix and testing
• bugfix leonardo #170
• bugfix - no index search after specifying natural direction
• Low level API restructuring
  • Driver API
  • Current sense API
• New debugging interface - see in docs
  • Static class SimpleFOCDebug
• CurrentSense API change - added method linkDriver() - see in docs
• Low-side current sensing - see in docs
  • ESP32 generic support for multiple motors
  • Added low-side current sensing support for stm32 - only one motor
    • f1 family
    • f4 family
    • g4 family
• New appraoch for current estimation for torque control using voltage - see in docs
  • Support for motor KV rating - back emf estimation
  • Using motor phase resistance
• KV rating and phase resistance used for open-loop current limiting as well - see in docs

Arduino SimpleFOClibrary v2.2

This video demonstrates the SimpleFOClibrary basic usage, electronic connections and shows its capabilities.

Features

• Easy install:
  • Arduino IDE: Arduino Library Manager integration
  • PlatformIO
• Open-Source: Full code and documentation available on github
• Goal:
  • Support as many sensor + motor + driver + current sense combination as possible.
  • Provide the up-to-date and in-depth documentation with API references and the examples
• Easy to setup and configure:
  • Easy hardware configuration
  • Each hardware component is a C++ object (easy to understand)
  • Easy tuning the control loops
  • SimpleFOCStudio configuration GUI tool
  • Built-in communication and monitoring
• Cross-platform:
  • Seamless code transfer from one microcontroller family to another
  • Supports multiple MCU architectures:
    • Arduino: UNO, MEGA, DUE, Leonardo ....
    • STM32
    • ESP32
    • Teensy
    • many more ...

Arduino SimpleFOCShield v2.0.4

Features

• Plug & play: In combination with Arduino SimpleFOClibrary - github
• Low-cost: Price of €15 - Check the pricing
• In-line current sensing: Up to 3Amps/5Amps bidirectional
  • configurable: 3.3Amps - 3.3V adc, 5Amps - 5V adc
• Integrated 8V regulator:
  • Enable/disable by soldering pads
• Max power 120W - max current 5A, power-supply 12-24V
  • Designed for Gimbal motors with the internal resistance >10 Ωs.
• Stackable: running 2 motors in the same time
• Encoder/Hall sensors interface: Integrated 3.3kΩ pullups (configurable)
• I2C interface: Integrated 4.7kΩ pullups (configurable)
• Configurable pinout: Hardware configuration - soldering connections
• Arduino headers: Arduino UNO, Arduino MEGA, STM32 Nucleo boards...
• Open Source: Fully available fabrication files - how to make it yourself

Getting Started

Depending on if you want to use this library as the plug and play Arduino library or you want to get insight in the algorithm and make changes there are two ways to install this code.

• Full library installation Docs
• Minimal project builder Docs

Arduino SimpleFOClibrary installation to Arduino IDE

Arduino Library Manager

The simplest way to get hold of the library is directly by using Arduino IDE and its integrated Library Manager.

• Open Arduino IDE and start Arduino Library Manager by clicking: Tools > Manage Libraries....
• Search for Simple FOC library and install the latest version.
• Reopen Arduino IDE and you should have the library examples in File > Examples > Simple FOC.

Using Github website

• Go to the github repository
• Click first on Clone or Download > Download ZIP.
• Unzip it and place it in Arduino Libraries folder. Windows: Documents > Arduino > libraries.
• Reopen Arduino IDE and you should have the library examples in File > Examples > Simple FOC.

Using terminal

• Open terminal and run

cd #Arduino libraries folder
git clone https://github.com/simplefoc/Arduino-FOC.git

• Reopen Arduino IDE and you should have the library examples in File > Examples > Simple FOC.

SimpleFOClibrary minimal project builder

For those willing to experiment and to modify the code I suggest using the minimal project builder minimal branch.

This code is completely independent and you can run it as any other Arduino Sketch without the need for any libraries.

All you need to do is:

• Go to minimal branch
• Follow the tutorial in the README file and choose only the library files that are necessary for your application.

Arduino code example

This is a simple Arduino code example implementing the velocity control program of a BLDC motor with encoder.

NOTE: This program uses all the default control parameters.

#include <SimpleFOC.h>

//  BLDCMotor( pole_pairs )
BLDCMotor motor = BLDCMotor(11);
//  BLDCDriver( pin_pwmA, pin_pwmB, pin_pwmC, enable (optional) )
BLDCDriver3PWM driver = BLDCDriver3PWM(9, 10, 11, 8);
//  Encoder(pin_A, pin_B, CPR)
Encoder encoder = Encoder(2, 3, 2048);
// channel A and B callbacks
void doA(){encoder.handleA();}
void doB(){encoder.handleB();}


void setup() {  
  // initialize encoder hardware
  encoder.init();
  // hardware interrupt enable
  encoder.enableInterrupts(doA, doB);
  // link the motor to the sensor
  motor.linkSensor(&encoder);
  
  // power supply voltage [V]
  driver.voltage_power_supply = 12;
  // initialise driver hardware
  driver.init();
  // link driver
  motor.linkDriver(&driver);

  // set control loop type to be used
  motor.controller = MotionControlType::velocity;
  // initialize motor
  motor.init();
  
  // align encoder and start FOC
  motor.initFOC();
}

void loop() {
  // FOC algorithm function
  motor.loopFOC();

  // velocity control loop function
  // setting the target velocity or 2rad/s
  motor.move(2);
}

You can find more details in the SimpleFOC documentation.

Example projects

Here are some of the SimpleFOClibrary and SimpleFOCShield application examples.

Documentation

Find out more information about the Arduino SimpleFOC project in docs website

Arduino FOC repo structure

Branch	Description	Status
master	Stable and tested library version
dev	Development library version
minimal	Minimal Arduino example with integrated library