Torque-Actuated Multimodal Locomotion of Ferrofluid Robot With Environment and Task Adaptability

Soft microrobotics have recently been an active field that advances microrobotics with new robot design, locomotion, and applications. In this paper, we study the ferrofluid robot (FR), which has soft nature and exhibits paramagnetism. Currently, the FR locomotion is usually realized by magnetic force. To enable the FR with more locomotion modes for environment and task adaptability, we program three dynamic field forms and realize three corresponding torque-actuated locomotion modes: Rolling, Wobbling, and Oscillating. The torque actuation of the FR is formulated, and the three locomotion modes are characterized. With the implementation of automated tracking and control algorithms, the controllability of these modes is testified. We then fabricate different environments to validate the adaptability of the FR that can switch its locomotion mode accordingly. Finally, utilizing the oscillating mode and wobbling mode, we demonstrate the transport of lipophilic and hydrophilic cargoes, respectively, showing the task adaptability.