Model-based dynamic feedback control of a planar soft robot: trajectory tracking and interaction with the environment

TLDR

Soft robots’ elastic bodies enable dynamic motion and safe interaction with unstructured environments, yet suitable control strategies are lacking. This study introduces, for the first time, closed‑loop dynamic controllers for a continuous soft robot, presenting two architectures for trajectory tracking and surface following. The two controllers preserve the robot’s natural softness, adapt to unstructured interactions, and are validated through extensive simulations and planar‑motion experiments. Analytical proofs confirm the controllers’ validity under the model’s assumptions.

Abstract

Leveraging the elastic bodies of soft robots promises to enable the execution of dynamic motions as well as compliant and safe interaction with an unstructured environment. However, the exploitation of these abilities is constrained by the lack of appropriate control strategies. This work tackles for the first time the development of closed-loop dynamic controllers for a continuous soft robot. We present two architectures designed for dynamic trajectory tracking and surface following, respectively. Both controllers are designed to preserve the natural softness of the robot and adapt to interactions with an unstructured environment. The validity of the controllers is proven analytically within the hypotheses of the model. The controllers are evaluated through an extensive series of simulations, and through experiments on a physical soft robot capable of planar motions.