An Underactuated Omnidirectional Docking Mechanism for Modular Serpentine Robots with DNA-Inspired Helical Continuum...

Area of Science:

• Robotics
• Bio-inspired Engineering
• Mechanical Engineering

Background:

• Existing serpentine robots struggle with modular docking and adaptive grasping in unstructured environments.
• A balance between structural stiffness and motion dexterity is often lacking in current designs.

Purpose of the Study:

• To propose a Modular Omnidirectional Serpentine Robot (MOSR) integrating locomotion, grasping, and modular reconfiguration.
• To address limitations in docking reliability, grasping adaptability, and stiffness-dexterity balance in serpentine robots.

Main Methods:

• Developed a helical continuum unit with DNA-inspired tendons for compliant bending and axial stiffness.
• Integrated an underactuated spherical docking gripper with adaptive fingers.
• Modeled kinematics using an improved Denavit-Hartenberg method and verified workspace with MATLAB.
• Established and validated stiffness models via finite element analysis.
• Analyzed docking feasibility using angular parameters and simulated receiver-engager interactions.

Main Results:

• The helical unit demonstrated improved axial stiffness.
• The spherical gripper supports stable one-to-one and one-to-many docking.
• Docking analysis indicated a feasible docking region covering 61.1% of the receiver surface.
• A 3D-printed prototype achieved 15.3 mm/s locomotion speed on grass.
• The prototype successfully demonstrated terrain traversal, steering, obstacle crossing, adaptive grasping, and stable docking.

Conclusions:

• The MOSR successfully integrates locomotion, grasping, and modular reconfiguration within a single module.
• The proposed design overcomes key limitations of existing serpentine robots.
• The findings validate the feasibility of the MOSR for operation in unstructured environments.