2 research outputs found

    Needle Steering Fusing Direct Base Manipulation and Tip-based Control

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    International audienceWorks on robotic needle steering often consider either tip-based control of flexible beveled tip needles or control of the bending of symmetric tip needles. In this paper a control law for needle steering which uses both direct manipulation of the needle base and the control of the tip deflection, is proposed. A 3D model of a beveled tip needle is used to determine the base motion that is needed to obtain the desired tip motion. The needle-tissue interaction model uses local virtual springs placed along the needle shaft and takes into account the interaction forces at the bevel. Online estimation and update of this model parameters is performed via visual feedback. The low level controller uses the task function framework to allow control of the tip velocity. Additionally duty cycling method is used if a reduction of the natural deflection of the needle tip is needed. Finally an experimental targeting task in a gelatin phantom is presented for preliminary validation of the framework. The method provided sub-millimeter accuracy on a target that would be unreachable using only tip-based control
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