[Task] Gripper controller

[Q3rkses]

Description of task

Design and implement a simple gripper controller for the AUV that can:

• Clamp and release (open/close jaws).
• Rotate roll (continuous or limited, per hardware).
• Pitch up/down if the mechanism is non-static (disable if hardware is static).

The controller must use the **correct topics/messages to the gripper coordinate with the responsible embedded personnel to finalize the ROS2 ⇄ MCU message schema, units, rates, and safety behaviors. Provide simulator support and designated scenarios for validation.

Suggested Workflow

1. Align with embedded team and mechanical team: confirm hardware capabilities (max roll/pitch, speeds, torque/force/current limits, endstops, homing), command/feedback message formats, and E-stop behavior.
2. Implement controller node: can be as complex or as simple as you like, but remember that it needs to work, and that the gripper can be within good margins of error so it does not need to be super cutting edge.

Specifications

Control objectives

• Clamp/Release: reliable execution within a bounded time.
• Roll: track commanded angle or rate with bounded overshoot; respect mechanical/electrical limits.
• Pitch (if enabled): track commanded angle/rate with bounded overshoot; disable feature cleanly on static hardware.
• Robustness: reject invalid commands; recover gracefully from transient faults and communication loss.

Suggested testing

• Static orientation tests:
  • With DP holding position, command sequences: CLAMP → RELEASE → CLAMP; verify time-to-action and final state.
  • Roll steps (e.g., 0°→45°→−45°→0°), measure settling time and overshoot.
  • (If enabled) Pitch steps within limits; verify no interference with vehicle body.

Placement

• New package: control/gripper_controller/ (node, params, README, launch)
• Tests: tests/gripper_controller/ (state-machine unit tests + simulator scenarios)
• Wiki: “Gripper Controller” (I/O schema, safety, tuning, and test procedures)

Contacts

• Coordinate with embedded/MCU responsible — @forrisdahl
• Control lead — @Q3rkses
• Software lead — @jorgenfj

Code Quality

• Every function in header files are documented (inputs/returns/exceptions)
• The project has automated tests that cover MOST of the functions and branches in functions (pytest/gtest)
• The code is documented on the wiki (provide link)

[Andeshog]

Relevant same task from last year. Did not really get to start on it, but made a repo which can hold the code.

[ApatShe]

Gripper Control Refactor - TODO List

1. Create New vortex-msgs Interface

• Design intermediate topic message structure
  • Define message fields (gripper command, mode source, etc.)
  • Choose appropriate data types
  • Document message purpose and usage
• Create new message/service definition in vortex-msgs
  • Choose descriptive name (e.g., GripperCommand.msg or GripperControlInput.msg)
  • Add to CMakeLists.txt
  • Add to package.xml dependencies
• Build and verify message generation
• Update vortex-msgs documentation

2. Refactor Joy Topic Publisher

• Locate Joy topic publisher node
  • Identify package and source file
  • Document current implementation
• Refactor publisher implementation
  • Change output topic from Joy to new intermediate topic
  • Update topic name in launch files
  • Ensure message compatibility
• Test manual joystick control
  • Verify topic publishes correctly
  • Check message content and frequency

3. Update gripper_interface_ros Node

• Modify subscription in gripper_interface_ros
  • Change subscriber from Joy topic to intermediate topic
  • Update callback function signature if needed
  • Update message type includes
• Update package dependencies
  • Add vortex_msgs dependency to CMakeLists.txt
  • Add vortex_msgs dependency to package.xml
• Test integration
  • Verify subscription receives messages
  • Test both manual and auto modes
  • Validate gripper response

4. Testing & Validation

• Integration testing
  • Test manual mode (joystick → intermediate → gripper)
  • Test auto mode (auto signal → intermediate → gripper)
  • Test mode switching
• Update documentation
  • Document new topic architecture
  • Update README files
  • Add comments to code changes

5. Cleanup & Review

• Code review preparation
  • Clean up debug code
  • Ensure consistent naming conventions
  • Verify all commits are well-documented
• Create pull request with task list