DDSM115 Driver (ESP UART)

Use this driver to control DDSM115 motors via an external ESP board connected over UART.

Overview

This ROS 2 package provides a node ddsm115_driver_node that communicates with the ESP board using a custom binary protocol.

• Port: Defaults to /dev/ttyS2 (configurable).
• Control: Velocity control via /wheel_vel.
• Feedback: Raw odometry via /raw_odom.
• Safety: 2.0s command watchdog stops motors if no command is received.

Interface

Parameters

Parameter	Type	Default	Description
device	string	/dev/ttyS2	Serial port device path

topics

Subscribers

• /wheel_control (ddsm115_driver/msg/ControlMode)
  • Set driver mode (0: IDLE, 1: POSITION, 2: VELOCITY).
• /wheel_vel (ddsm115_driver/msg/WheelVel)
  • Target RPM for left and right wheels.
• /wheel_pos (ddsm115_driver/msg/WheelPos)
  • Target position (degrees) for left and right wheels.

Publishers

• /raw_odom (ddsm115_driver/msg/RawOdom)
  • Feedback status (RPM, Current, etc.) published at 20Hz.

Usage

Launch

Run the driver using the launch file:

ros2 launch ddsm115_driver ddsm115.launch.py device:=/dev/ttyS2

Manual Control Examples

1. Set Mode to Velocity

ros2 topic pub --once /wheel_control ddsm115_driver/msg/ControlMode "{mode: 2}"

• 0: IDLE
• 1: POSITION
• 2: VELOCITY

2. Send Velocity Command

Send continuous commands (required to satisfy watchdog):

ros2 topic pub -r 10 /wheel_vel ddsm115_driver/msg/WheelVel "{left_rpm: 50, right_rpm: -50}"

3. Stop Motors

ros2 topic pub -r 10 /wheel_vel ddsm115_driver/msg/WheelVel "{left_rpm: 0, right_rpm: 0}"

4. Set Mode to Idle

ros2 topic pub --once /wheel_control ddsm115_driver/msg/ControlMode "{mode: 0}"

5. Monitor Feedback

ros2 topic echo /raw_odom