Sliding Mode Control of Steerable Needles

Abstract

Steerable needles can potentially increase the accuracy of needle-based diagnosis and therapy delivery, provided they can be adequately controlled based on medical image information. We propose a novel sliding mode control law that can be used to deliver the tip of a flexible asymmetric-tipped needle to a desired point, or to track a desired trajectory within tissue. The proposed control strategy requires no a priori knowledge of model parameters, has bounded input speeds, and requires little computational resources. We show that if the standard nonholonomic model for tip-steered needles holds, then the control law will converge to desired targets in a reachable workspace, within a tolerance that can be defined by the control parameters. Experimental results validate the control law for target points and trajectory following in phantom tissue and ex vivo liver. Experiments with targets that move during insertion illustrate robustness to disturbances caused by tissue deformation.

Design of an actively controlled steerable needle with tendon actuation and FBG-based shape sensing

“…Recent research focus is shifting toward practical applicability, covering the inclusion of planning uncertainties with respect to tissue variability [14], the consideration of torsional friction [15], and the reduction of model dependencies on a-priori information [16].…”

Needle steering fusing direct base manipulation and tip-based control

“…We define the desired behavior of the task asẽ 2 = ω b , where ω b is given by a smoothed sliding mode controller [7]. This control law allows to steer σ toward zero and is such as:…”

“…Many control schemes have then been proposed using these models. In [7] sliding mode control is proposed such that the bevel is always oriented toward the target. Hauser et al [8] use the helical trajectories obtained when simultaneously inserting and rotating the needle.…”

“…The originality of our approach is to use transverse motion control to increase the reachable region and to switch to a duty cycling method when a reduction of the natural curvature is needed, i.e when rather straight trajectories must be achieved. For the rotation along the shaft, we use sliding mode control [7] to orient the bevel in such a way that the needle tends to bend in the desired direction. We also added a secondary task to reduce the tissue deformations when possible.…”

Dispositivo robótico para guiagem de agulhas flexíveis em procedimentos minimamente invasivos

“…Nos últimos dois anos, começou-se a utilizar agulhas tubulares [29,31,43], formadas por tubos de Nitinol ao invés de arames maciços. Isso possibilita posicionar sensores dentro da agulha, medindo informações sobre a ponta da agulha durante a inserção.…”