Modeling of vacuum grippers for the design of energy efficient vacuum-based handling processes

Vacuum-based handling is widely used in industrial production systems, particularly for hand-ling of sheet metal parts. The process design for such handling tasks is mostly based on approximate calculations and best-practice experience. Due to the lack of detailed knowledge about the parameters that significantly influence the seal and force transmission behavior of vacuum grippers, these uncertainties are encountered by oversizing the gripping system by a defined safety margin. A model-based approach offers the potential to overcome this limitation and to dimension the gripping system based on a more exact prediction of the expected maximum loads and the resulting gripper deformation. In this work, we introduce an experiment-based modeling method that considers the dynamic deformation behavior of vacuum grippers in interaction with the specific gripper-object combination. In addition, we demonstrate that for these specific gripper-object combinations the gripper deformation is reversible up to a certain limit. This motivates to deliberately allow for a gripper deformation within this stability range. Finally, we demonstrate the validity of the proposed modeling method and give an outlook on how this method can be implemented for robot trajectory optimization and, based on that, enable an increase of the energy efficiency of vacuum-based handling of up to 85%.

Measurement of High Strain Rate Indentation-Induced Deformations in Al2O3/SiCp Composite Ceramics

Al2O3/SiCp composite ceramics with 2 vol%, 5 vol% and 10 vol% SiC nanoparticles additions were hot pressed at 1650 °C. The polished ceramic discs were prepared and indented at high strain rate using a compressed gas gun with tiny tungsten carbide bullets. The microstructure and mechanical properties were obtained to explain the dynamic deformation behavior of Al2O3/SiCp ceramics. Cr3+ fluorescence mapping was used to examine the residual stress and plastic deformation induced on the surface of each target. The residual compressive stress area around the crater was evenly distributed, while the greatest plastic deformation was found at the hitting point of the bullet tip. It can be calculated that the high temperature of 1400K may be produced at the instant of the bullet impact and result in large plastic deformation region and low residual stress of the Al2O3/SiCp ceramic.