A new duty-cycling approach for 3D needle steering allowing the use of the classical visual servoing framework for targeting tasks

We present a method for three dimensional steering of a beveled-tip flexible needle that can be used in medical robotics for percutaneous assistance procedures. The proposed solution is based on the design of a new duty-cycling control strategy that makes possible to control three degrees of freedom (DOFs) of the needle tip. These DOFs correspond to two rotations that are performed around the needle tip lateral axes and one translation along the needle shape axis. This approach has two advantages compared to existing methods. First it does not rely on a trajectory planning and opens therefore numerous closed-loop control scheme possibilities as for example the implementation of the visual servoing framework based on the task function approach. Second, it does not constraint the needle to follow a succession of planar arcs but allows non planar 3D trajectories. Experimental results of a targeting task performed by visual servoing demonstrate the feasibility of this new concept and its robustness to needle kinematic model errors.