Controlling Concentric Tube Robots while Enforcing Shape Constraints

Lilge, Sven; Burgner-Kahrs, Jessica
Workshop on Open Challenges and State-of-the-Art in Control System Design and Technology Development for Surgical Robotic Systems, IEEE International Conference on Robotics and Automation, 2019
Controlling Concentric Tube Robots while Enforcing Shape Constraints


Concentric tube robots are often studied as surgical robots in the context of minimally invasive interventions. During such applications they are mostly considered to be teleoperated or operated with increasing levels of autonomy. While it is necessary to control the robot’s end-effector position with sufficient accuracy, it is also desirable to enforce shape constraints during robot motion, especially when considering applications in constrained environments. To meet shape constraints, the kinematic redundancy of a concentric tube robot regarding its end-effector position has to be resolved efficiently. In this work, a method based on differential kinematics is applied to control and resolve this redundancy with respect to discretely defined shape constraints. Overall, remaining end-effector positioning errors below 0.3 mm can be achieved while satisfying shape constraints during the robot’s motions with a median accuracy of 0.16 mm.