How to transport barrels from one conveyor belt to another

This engineering improvisation is about the challenge of transporting barrels from a lower conveyor belt to a higher one without the barrels tipping over. It is a creative process of trial and error, and leaves us with an unresolved issue. It would be great if you can help me figure out why the is pulsating so much!
These simulations are made with Algoryx Momentum Granular inside ANSYS SpaceClaim. Visit www.algoryx.se... for more information.