BldcMotor Example

This example shows the use of the BldcMotor component to drive a BLDC motor (such as a tiny gimbal motor) using Field-Oriented Control (FOC) in both open-loop and closed-loop control schemes for both position and velocity control.

How to use example

Hardware Required

This example requires a lot of hardware such as:

  • Magnetic encoder chip (this example uses Mt6701)

  • BLDC Motor Driver chip (this example was tested with the TMC6300 BOB dev board)

  • Some mounting hardware to mount the motor, magnet, encoder, etc.

:warning:

NOTE: you MUST make sure that you run the example with the zero_electrical_offset value set to 0 (or not provided) at least once otherwise the sample will not work and could potentially damage your motor.

Currently, this is designed to be run on a TinyS3 connected to the motor driver and encoder via breadboard with the motor powered via a benchtop power supply at 5V.

Configure the project

idf.py menuconfig

  • If there is any project configuration that the user must set for this example, mention this here.

Build and Flash

Build the project and flash it to the board, then run monitor tool to view serial output:

idf.py -p PORT flash monitor

(Replace PORT with the name of the serial port to use.)

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example Output

Screenshots (if appropriate, e.g. schematic, board, console logs, lab pictures):

image image

Video

https://github.com/esp-cpp/espp/assets/213467/9a48a29f-9901-44d2-a68e-b27c9220cc24

Troubleshooting

Make sure to run the example once with zero_electrical_offset set to 0 so that the motor will go through a calibration / zero offset routine. At the end of this startup routine it will print the measured zero electrical offset that you can then provide within the code, at which point it will not need to run the calibration routine.

You must run this calibration any time you change your hardware configuration (such as by remounting your motor, magnet, encoder chip).

Example Breakdown

This example is relatively complex, but builds bldc motor control using the following components:

  • espp::Mt6701

  • espp::BldcDriver

  • espp::BldcMotor

  • ESP-IDF’s i2c peripheral driver

  • espp::Task for updating the target

  • espp::Task for logging state

You combine the Mt6701 and BldcDriver together when creating the BldcMotor and then simply use the API provided by the BldcMotor to set targets for control (position or velocity) and to get the state of the motor.