Optimal Design and Analytical Modeling of a Soft Fin-Ray Effect Gripper Finger Using the Finite Rigid Elements Method
2026-06-02 • Robotics
Robotics
AI summaryⓘ
The authors designed a soft robotic finger inspired by fish fins to gently pick up delicate things like tomatoes. They used a special modeling method called the Finite Rigid Elements Method (FREM) that helps predict how the finger bends and moves, even though soft materials are tricky to understand. They also made a detailed computer model with ANSYS and tested their predictions with experiments, finding their models were very accurate. The finger was optimized based on how much it bends, how stress spreads, and the force it applies for the best performance.
Soft roboticsFin Ray EffectFinite Rigid Elements MethodFinite Element ModelANSYSForce controlSoft gripperStress distributionTip displacement
Authors
Sara Adeli, Hassan Sayyaadi
Abstract
Fin Ray-inspired soft grippers offer a promising solution for gently handling delicate, irregular objects, especially in agriculture. The objective of this research is to design, fabricate, and model a Fin Ray Effect (FRE) soft gripper finger to enable precise force control in future applications. This design aims to gently grasp delicate agricultural products, such as tomatoes, that require both adaptability and accurate force application. To address the inherent challenges of soft robotics, including nonlinear behavior, infinite degrees of freedom, and variable material properties, the Finite Rigid Elements Method (FREM) was employed for modeling. This method preserves analytical accuracy while providing a reliable foundation for the development of a force controller in later stages. A detailed Finite Element Model (FEM) was created using ANSYS, and the analytical results were validated through simulation and experimental testing. The gripper's fingers were optimized based on four key criteria: tip displacement, total deflection, stress distribution, and contact force. The optimal finger configuration includes a length of 30 mm, rib spacing of 10 mm, seven ribs angled at -15 deg, and a rib thickness of 1 mm. Theoretical modeling using the FREM predicted finger deformation with a 3% error, while the ANSYS numerical model achieved 2% error.