Modelling the Deformation of Biologically Inspired Flexible Structures for Needle Steering

Abstract

Recent technical advances in minimally invasive surgery have been enabled by the development of new medical instruments and technologies. To date, the vast majority of mechanisms used within a clinical context are rigid, contrasting with the compliant nature of biological tissues. The field of robotics has seen an increased interest in flexible and compliant systems, and in this paper we investigate the behaviour of deformable multi-segment structures, which take their inspiration from the ovipositor design of parasitic wood wasps. These configurable structures have been shown to steer through highly compliant substrates, potentially enabling percutaneous access to the most delicate of tissues, such as the brain. The model presented here sheds light on how the deformation of the unique structure is related to its shape, and allows comparison between different potential designs. A finite element study is used to evaluate the proposed model, which is shown to provide a good fit (root-mean-square deviation 0.2636mm for 4-segment case). The results show that both 3-segment and 4-segment designs are able to achieve deformation in all directions, however the magnitude of deformation is more consistent in the 4segment case.

Cyclic Motion Control for Programmable Bevel-Tip Needle 3D Steering: A Simulation Study

“…To compare the performance of the low level controllers, the segment displacement configuration is sent to a forward model that converts segment offsets to achieved curvature and simulates the path taken. This forward model is based on multi-segment beam deformation and was first presented in [19].…”