Passivity-Based Task Space Control of Hybrid Rigid-Soft (HyRiSo) Robots with Parametric Uncertainty

This paper introduces a novel robotic system, coined as a hybrid rigid-soft (HyRiSo) robot composed of rigid links and soft links serially attached. HyRiSo combines the benefits of the dexterity of a soft manipulator with the support capability of a classical stiff arm. Due to the heterogeneous modes of actuation for the revolute joints and to enable the bending of the soft links, it is challenging to design an integrated controller for this class of robots. We demonstrate in this paper that the well-known passivity-based adaptive and robust controllers can be utilized to address this challenge. Specifically, we use these controllers for task space tracking in the presence of uncertain mass, stiffness, damping and actuation. We demonstrate the effectiveness of the proposed HyRiSo robot by showing task space tracking in the presence of complex obstacles and joint limits. We provide numerical examples using a 2-rigid-2-soft HyRiSo robot and compare the performance of the proposed task space controllers illustrating the efficacy of these frameworks.