encoders

ROS Node to interact with encoders

Initialize ROS2 package

1. Create ros2 C++ package

   ros2 pkg create --build-type ament_cmake --node-name encoders encoders

2. Build package

   colcon build --packages-select encoders

3. Source the setup file

   . install/setup.bash

4. Use the package

   ros2 run encoders encoders

5. Customize package.xml

I2C

It connects to i2c with the i2c_server node.

Hardware

This package interact with an ESP32 board installed on the Maile Vehicle. The communication is made on I2C where the board has been setup as a SLAVE with ID:0x09.

Registers to work with

1. Read 0x09

• It will respond with 1 byte, how many encoders are programmed (uint8_t)

1. Read 0x10

• It will respond with (4+2*N_ENCODERS) bytes; first 4 bytes are microsecods from last call (uint32_t) after that, 2 bytes for each programmed encoder counting tick from the last call (uint16_t) the encoders order is:

1. spur gear motor encoder
2. front right wheel encoder
3. rear right wheel encoder
4. rear left wheel encoder
5. front left wheel encoder

NOTES

• spur gear (high gear ratio = 1:5.22, low gear ratio = 1:14.45)

• tick at spur gear / round = 10

• wheel circumference = 0.559 meter

• tick for wheel / round = 12

Copyright and License

This software contains code licensed as described in LICENSE.