Feasibility study of robotic needles with a rotational tip-joint and notch patterns

In this paper, we present the design of a steerable needle with proximal notch patterns for compliance and an embedded rotational tip joint for articulation. The device is fabricated by laser machining NiTi tube so that an inner working channel exists (to enable delivery of fluids, drugs or microtools) and no assembly is required for the joints. We formulate its model based on the classical Cosserat Rod theory. This is extended with incremental state prediction and a simple spring model for tissue reaction to integrate into a planning algorithm based on Dynamic Region RRT which efficiently explores the needle's state space. The planner was initialized with a target zone and arbitrary anatomical obstacles before running simulations which propagated incremental state changes at every step while adhering to constraints based on the physical system. Finally, we demonstrate the steering capability of the needle through insertion tests into a phantom.