Kinematics and performance analysis of a novel concentric tube robotic structure with embedded soft micro-actuation

• Generic modeling of continuum robots augmented with embedded soft micro-actuation
• Kinematic analysis with holonomy and redundancy supply for the proposed structures
• Workspace characterization and performance indices applied to continuum robots

Continuum robots have shown astounding abilities to assist surgeons reaching confined spaces in the human body. Thus, accurate control of these manipulators, and particularly concentric tube robots, is required in order to achieve intracorporeal microrobotic interventions. We present hereby an improvement of this kinematic structure based on embedded soft micro-actuators. Two models for single and double direction curvature control are introduced. We demonstrate that kinematics are enhanced with respect to the standard approach in terms of holonomy, actuation redundancy and workspace covering. Further kinematic analysis enables the detection of singular configurations. The number of the end-effector pose occurrences that can be reached in a given volume (one cubic millimeter) are computed as well. Finally, the advantages of the novel structures are proven using performance indices.