Extended bicycle model for needle steering in soft tissue

This paper represents an extension to the kinematic bicycle model for beveled-tip needle motion in soft tissue, which accounts for non-constant curvature paths for the needle tip. For a tissue that is not stiff relative to the needle, the tissue deformation caused by needle insertion deviates the needle tip position from a constant curvature path. The proposed model is obtained by replacing the bicycle wheels with omnidirectional wheels that move in two orthogonal directions independently. Such wheels can move sideways, providing a means for modeling the deviations of the needle tip from a constant curvature path by incorporating new parameters in the model. Using an experimental setup, the needle is inserted into soft phantom tissue at different constant velocities and model parameters are fitted to experimental data. The model is verified by comparing the results from the model to empirical data.