Haptic Rendering on Deformable Anatomical Tissues with Strong Heterogeneities

This paper is focus on the development of a haptic rendering method to simulate interactions with heterogeneous deformable materials, such as anatomical components. Indeed, the strong heterogeneities of the biological tissues involves numerical and real-time issues to simulate the deformations and the mechanical interactions between the organs and the surgical tools. In this paper, we propose a new haptic algorithm adapted to the modeling of heterogeneous biological tissues, based on non-linear finite element model. The central contribution is the use of a triple asynchronous approach: one loop at low rate, which computes a preconditionner that solves the numerical conditioning problems; a second at intermediate rate, to update the model of the biological simulation; and the haptic loop which provides the feedback to the user at high rate. Despite of the desynchronization, we show that the calculation of haptic forces remains accurate compared to the model. We apply our method to a challenging microsurgical intervention of the human middle ear. This surgery requires a delicate gesture in order to master the applied forces.