A structure-preserving FEM-model for the control of planar soft robots

Abstract

A major challenge in soft robotics is model-based control. Many common models for soft robots suffer a loss of mechanical structure when model reduction is performed. This is a significant problem for control, since many control methods, e.g. energy-based control, rely heavily on this structure. In this paper, we present an alternative finite dimensional reduction method that preserves the mechanical structure of the model of a soft robot. Using a form of finite element Galerkin projection, our approach incorporates this reduction process into a variational framework that is suitable for control applications. As a proof-of-principle, we present the model of a planar soft robot with preserved mechanical structure and a simple control paradigm. With this method, soft robots can be described in a form that is suitable for control strategies that depend on their mechanical structure, such as energy-based control.