Design and mechanics of continuum robots for surgery

This dissertation describes design and modeling of two new flexible, continuous backbone robotic dexterity enhancement devices, and algorithms to robotically manipulate them in surgery. These steerable needles and active cannulas provide dexterity in thin (needle-sized) form factors, permitting surgical tools to “turn corners” inside the human body. The robotic tool manipulation algorithms are useful for rapidly and accurately aligning many kinds of surgical tools with planned poses and entry vectors. Drawing on techniques from artificial intelligence, they do not require cumbersome calibration, complete knowledge of robot kinematics, or even encoding, making them well-suited to uncertain real-world clinical environments. Simulations and experimental results demonstrate the accuracy and speed of the algorithms. When an intervention is needle-based, steerable needles provide a means to achieve dexterity within soft tissue after insertion begins. Asymmetric forces generated by a bevel tip are harnessed robotically to generate controllable deflection, and curvature is enhanced by design of needle properties and geometry. The needle is modeled as a nonholonomic system with model parameters fit to experimental data. A new control