Kinematic Modeling of A Pneumatic Tubular Bending Actuator for Robotic Navigation in Narrow Luminal Organs

Telerobotic endoluminal interventions have brought significant advancements to minimally invasive surgery, and fluidically-driven soft bending actuators are crucial for navigating tortuous anatomical pathways. However, designing and modeling such actuators while balancing flexibility and structural integrity remains challenging. This study develops a kinematic model for a pneumatic tubular bending actuator, which is simplified as a piecewise constant-curvature arc. Simulations show that the actuator’s bending angle can exceed 200 degrees by adjusting design parameters, with the angle increasing proportionally with air pressure and being influenced by factors like elastic modulus contrast, wall thickness, outer diameter, and initial length. Additionally, the actuator enables successful catheter deployment in a vascular phantom, navigating through branches to reach the target. This model provides theoretical guidance for precise control of such actuators in robotic navigation within luminal organs.