Manipulation with suction cups using external contacts

Abstract

Suction cups are the most common manipulation effectors in industry, but they are mostly only used for the purpose of pick-and-place. This paper proposes to use suction cups for a wider variety of tasks with the help of external contacts. A major hurdle in improving the dexterity of suction cups is the challenge of soft material modeling. Model error causes inaccurate contact location estimation as well as undesirable control performance. In this work, we propose a general framework for manipulation with suction cups under external contacts. The solution consists of a locally linear force-deformation model for suction cups with large deformation, and an estimation-control framework which utilizes contact constraints and feedback control to counter modeling errors. We verify the efficacy of our method experimentally by tilting a block on a table with a suction cup. Our method works reliably under modeling error even under large suction cup deformation (over 40 degree of bending). We also show the superiority of suction cups by performing tasks that are not possible with any normal fingertip.