Integrated Locomotion and Deformation of a Magnetic Soft Robot: Modeling, Control, and Experiments

Magnetic robots have shown great potential in small-scale applications due to their wireless control mode. However, the existing efforts only deal with solid magnetic materials that could not deform. In this article, we focus on integrated locomotion and deformation of a class of magnetic soft robot made of ferrofluid. To this end, the magnetic model and dynamics model that takes the nonlinearity into account are first established. Then, the corresponding motion controllers are proposed, based on the results of feedback linearization and frequency-domain test results. Furthermore, an extended state observer is designed to reduce the perturbation due to model uncertainties. By integrating the control strategies of locomotion and active deformation, we demonstrate that the soft robot possesses the capability of conducting complex tasks such as passing through narrow environment and transporting multiple objects. Various experiments are also performed to demonstrate the effectiveness of the proposed control methods.