Numerical and Experimental Assessment of Elastomeric Vacuum Suction Cups for Robotic Waste-Sorting Applications

Robotic waste sorting requires end-effectors capable of handling objects with highly variable geometry, stiffness, surface condition and leakage characteristics. In such applications, the performance of a vacuum suction cup cannot be evaluated only on the basis of nominal holding force, since grasp initiation, contact compliance, airflow conditions and cyclic durability are strongly coupled. This paper presents a combined numerical and experimental assessment of elastomeric vacuum suction cups intended for robotic waste-sorting applications. Seven suction cup configurations were compared using computational fluid dynamics, finite element analysis and functional gripping tests performed on representative plastic waste objects. The CFD analysis was used to evaluate airflow velocity and generated vacuum level, while FEM simulations provided information on stress distribution and deformation under axial compression. For the selected suction cup, a durability-oriented wear prediction was additionally performed using stress data exported from the FEM model and processed with a dedicated Python tool. The complete vacuum system supplied by a side-channel blower was also analysed in Hopsan to assess leakage sensitivity and pressure margins for grasp initiation and secure holding. The results showed that the best flow performance was obtained for suction cups 1 and 2, but suction cup 2 provided the most favourable overall balance, combining the highest vacuum level, limited deformation, stable gripping performance and acceptable durability indicators. The study demonstrates that multi-criteria evaluation is necessary for selecting vacuum end-effectors for robotic waste sorting, especially when objects are deformable, contaminated or imperfectly sealed.