Control of a flexible bevel-tipped needle using super-twisting controller based sliding mode observer

Area of Science:

• Robotics
• Control Systems
• Medical Engineering

Background:

• Minimally invasive surgery (MIS) requires precise instrument control.
• Needle maneuverability is challenged by external disturbances and system complexities.
• Existing super twisting controllers with third-order sliding mode observers can lead to discontinuous control laws.

Purpose of the Study:

• To develop a robust and chattering-free control strategy for needle maneuverability in MIS.
• To propose a higher-order (n+1) sliding mode observer with a continuous control law.
• To enhance the accuracy of target reaching for flexible needles.

Main Methods:

• Implementation of a super twisting controller.
• Design of a higher-order (n+1) sliding mode observer.
• Utilizing the kinematic model of a bevel-tipped flexible needle.
• Simulation and experimental validation in biological tissue.

Main Results:

• Demonstrated chattering-free and stable needle maneuverability.
• Achieved accurate target reaching regulation.
• Verified the control methodology across various bevel angles in simulated and experimental settings.

Conclusions:

• The proposed higher-order sliding mode observer provides a robust solution for needle steering in MIS.
• Continuous control law ensures stable and precise instrument manipulation.
• The methodology is effective in biological tissue environments.