🎛️ Pitch Controller Node

Overview

The pitch_controller Node is designed for controlling the pitch angle of a BlueROV2 underwater vehicle. This node uses a PID controller to adjust the vehicle's movement and maintain the desired pitch.

✅ Prerequisites

Before using the Pitch Controller Node, ensure the following:

• The BlueROV2 Controller Node is running.

👨🏼‍💻 Node Parameters

The Pitch Controller Node accepts the following parameters:

• pitch_desired: Desired pitch setpoint (default: 0 degrees)
• pwm_max: Maximum PWM value (default: 1900 pwm)
• pwm_neutral: Neutral PWM value (default: 1500 pwm)
• kp: Proportional gain constant (default: 600)
• kd: Derivative gain constant (default: 50)
• enable: Enable/disable the pitch controller (default: True)

These parameters can be adjusted by updating the corresponding values in the launch file or using dynamic reconfigure.

📜 Input Topics

The Pitch Controller Node subscribes to the following topics:

• /bluerov2/attitude: Attitude data (Roll, Pitch, Yaw) - bluerov2_interfaces/Attitude
• /settings/pitch/set_pitch: Set the desired pitch - std_msgs/UInt16
• /settings/pitch/set_pid: Set PID parameters - bluerov2_interfaces/PID
• /settings/pitch/set_enable: Enable/disable the pitch controller - std_msgs/Bool

📜 Output Topics

The Pitch Controller Node publishes the following topics:

• /bluerov2/rc/pitch: PWM signal for pitch control - std_msgs/UInt16
• /settings/pitch/status: Pitch controller status - std_msgs/String

Understanding the /settings/pitch/status Topic

The /settings/pitch/status topic provides real-time status information about the Pitch Controller Node. This information is published as a JSON-formatted string and includes key details about the current state of the pitch controller. Here's an example of the JSON structure:

{
  "type": "pitch_controller",
  "enable": true,
  "kp": 600,
  "kd": 50,
  "pwm_max": 1900,
  "pwm_neutral": 1500,
  "pitch_desired": 0
}

[!WARNING]
This topic is read-only.

⚠️ Important Note

The Pitch Controller Node requires the BlueROV2 Controller Node to be running. Ensure that the BlueROV2 Controller Node is started before using the Pitch Controller Node.

⚒️ Example Usage

1. Set the desired pitch:

   ros2 topic pub /settings/pitch/set_pitch std_msgs/UInt16 "data: 15"
   

2. Adjust PID parameters:

   ros2 topic pub /settings/pitch/set_pid bluerov2_interfaces/PID "{kp: 700, kd: 60, pwm_max: 2000}"
   

3. Enable/disable the pitch controller:

   ros2 topic pub /settings/pitch/set_enable std_msgs/Bool "data: true"
   

Feel free to experiment with different parameters to optimize pitch control for your BlueROV2 underwater vehicle! 🎛️🚤