feat(models): Add Suction Gripper Model

[Rakshitha-Ireddi]

What this does

Adds a new Suction Gripper model to robosuite. This is a novel addition that enables vacuum-based manipulation using standard MuJoCo primitives, keeping the codebase lightweight and free of external mesh dependencies.

Features:

• New Asset: suction_gripper.xml defined entirely with internal geoms (cylinders) and includes an adhesion actuator.
• New Class: SuctionGripper implementation with correct action mapping ([-1, 1] input maps to [0, 1] adhesion force).
• Registration: Added to GRIPPER_MAPPING in robosuite/models/grippers/__init__.py.

How it was tested

• Unit Tests: Verified model instantiation, properties (dof=1, init_qpos=[]), and action formatting via a standalone script.
• Integration Tests: Ran existing gripper tests tests/test_grippers/test_all_grippers.py which now includes SuctionGripper. All tests passed.
• XML Validation: Verified XML generation and parsing within the Robosuite framework.

How to checkout & try? (for the reviewer)

# Run existing gripper tests to verify the new gripper
python -m pytest tests/test_grippers/test_all_grippers.py

Authors

• Ireddi Rakshitha
• Yaswanth Devavarapu