Step Climbing Control of Snake Robot with Prismatic Joints

Area of Science:

• Robotics
• Control Systems
• Mechanical Engineering

Background:

• Snake robots offer unique locomotion capabilities for complex environments.
• Sequential joint movements can limit efficiency and stability during locomotion tasks like step climbing.
• Controlling prismatic joints in multi-DOF robots presents challenges in avoiding singularities and ensuring stable motion.

Purpose of the Study:

• To develop and validate a control method for continuous prismatic joint movements in snake robots for effective step climbing.
• To enhance the stability and efficiency of snake robot locomotion in complex terrains.
• To prevent trailing part back-motion and avoid singular configurations during step climbing maneuvers.

Main Methods:

• A two-part control method comprising a shift reference generator and a trajectory tracking controller.
• Dividing prismatic joints into directly controlled and redundant groups for optimized motion control.
• Implementing link length control using a sigmoid function to manage joint behavior.

Main Results:

• Demonstrated effective step climbing capability of the developed 3D snake robot.
• Validated the proposed control method's effectiveness through experimental trials.
• Confirmed that sigmoid function-based link length limitation successfully prevents undesirable joint configurations and motion.

Conclusions:

• The proposed control method enables continuous prismatic joint movements for stable and effective robotic step climbing.
• Directly controlling link length is crucial for preventing back-motion and singularities in redundant joint configurations.
• The developed snake robot and control strategy show significant promise for navigating complex terrains.