Design, Fabrication, and Testing of a Novel Ferrofluid Soft Capsule Robot

This article proposes a ferrofluid soft capsule robot (FSCR) with magnetic actuation for diagnostic and therapeutic medical applications inside the human stomach. A composite shell consisted of ferrofluid, permanent magnet rings, and soft elastomer is developed for the FSCR, which is actuated remotely by an external permanent magnet. The proposed FSCR presents two novel characteristics. First, the composite shell not only has a soft outer surface that reduces damage to contact tissue but also an improved magnetic circuit with a combination of the ferrofluid and permanent magnet rings makes the locomotion of the device more controllable and secure. Second, the FSCR is equipped with a specific oscillation module that enables advanced functions such as drug-releasing. Detailed structure design and fabrication of the FSCR are presented in this study. The surface rolling locomotion of the FSCR is modeled and evaluated by numerical simulations, as well as the drug-releasing function. In order to verify the simulation result, an FSCR prototype is manufactured to perform experimental validation. The analysis result demonstrates the feasibility and efficiency of the proposed FSCR for drug releasing inside a printed human stomach model.