3D Capsule Compliant Gripper Based on Shape Optimization for Surgical Manipulation: Enhancing Precision in Lymph Node Isolation

Abstract Compliant grippers hold great promise in improving precision and safety in minimally invasive surgery (MIS), offering versatile solutions for tissue manipulation while minimizing trauma. A novel focus on a capsule-shaped compliant gripper introduces innovative design methodologies, including shape optimization and consideration of axillary lymph node dimensions. By integrating compliant beams internally and optimizing their shape, this gripper offers enhanced precision and adaptability in tissue manipulation, addressing specific challenges in delicate surgical interventions such as lymph node dissection in breast cancer surgery. An isogeometric approach for the analysis of geometrically nonlinear beam structures enables a seamless integration of exact geometry in computer-aided design (CAD) into the analysis framework. It incorporates frictionless beam contact conditions based on a regularized penalty law, which enables an efficient and accurate simulation of the compliant grippers. Optimization results demonstrate the efficacy of the methodology, producing a compliant beam configuration that applies a mean pressure of 204.93 Pa, with a maximized contact area facilitating form closure gripping. Experimental validation using a test bench confirms the consistency of the contact areas predicted by simulations, with force sensor measurements showing good agreement with simulation results in most cases. Minor discrepancies, particularly in higher-pressure regions, are attributed to sensor limitations but do not significantly impact the overall findings. Continued research and refinement of these methodologies are essential for furthering the field of compliant gripper design and its application in medical and surgical contexts.