A Comparison of the Workspace and Dexterity of Hybrid Concentric Tube Robot and Notched Wrist Systems

Concentric tube robots (CTR) and notched wrists are two technologies that have been investigated for medical applications. CTRs consist of pre-curved super-elastic tubes that are nested concentrically, and are linearly translated and axially rotated with respect to one another for movement. Separately, notched wrists are tubular instruments that can achieve large bending angles via notches that are cut into the tube and shortening actua- tion cables that run along their length. These two robotic tools have been investigated independently, but very few studies have explored combining them [1], [2]. This paper compares the workspace and dexterity of a three-tube CTR with two hybrid CTR and notch-cut wrist systems in simulation. These metrics are key in measuring the performance of robots, and particularly so for surgical robots. To perform complicated surgical tasks, it is critical to increase the number of spatial points that the robot can reach, and the number of obtainable orientations at these points.