Closed-loop 3D motion modeling and control of a steerable needle for soft tissue surgery

Percutaneous intervention has become a topic of interest in recent years, due to the many potential advantages for the patient. To date, several novel needle steering systems have been developed to improve both the accuracy and applicability of this type of surgery, but many of these can still only provide limited control of the trajectory between an entry site and a deep seated target. Our previous work describes the first prototype of a bio-inspired multi-part needle, codenamed STING, which can steer along planar trajectories within a compliant medium by means of a novel programmable bevel, where the steering angle is a function of the offset between interlocked needle segments. This paper presents our first attempt to model a bio-inspired 4-part needle, an extension of the planar steering system with the potential to steer along three-dimensional (3D) trajectories within a compliant medium. This paper introduces a 3D kinematic model and closed-loop controller for the needle, which is inspired by the modeling strategy employed for under-actuated underwater vehicles, followed by simulation results which demonstrate that 3D trajectory tracking can be completed successfully.