Surface Deformation Control of a Ferrofluid-Based Robotic Sheet for Object Handling

This paper describes the deformation control of a ferrofluid-based robotic sheet for object handling. The ferrofluid sheet consists of ferrofluid wrapped in thin polyethylene sheets and allows us to handle the transport of objects by controlling its deformation due to the characteristics of a ferrofluid. To control sheet deformation, we need to develop the sheet's mechanical model. Although the mechanical model of the ferrofluid has already been researched, the effect of the polyethylene sheet on the ferrofluid has not been considered. In this paper, we first verify the relationship between the fluid shape in the ferrofluid sheet and the thickness of the sheet on the fluid. Next, we verify the transportation method by making the ferrofluid sheet to move two balls simultaneously and a thin circular plate on its surface. We also confirm the deformation control of this robotic sheet in an alternative configuration. The achievement contributes to the technology for soft robotics and advanced control, opening new aspects for fluid-based 3-D manipulations. Note to Practitioners-This paper is motivated by the problem of manipulation of flexible objects. It is difficult for conventional manipulators to handle flexible objects, such as droplets, because their shapes dynamically deform while being handled. We considered that a flexible system should be able to conform to the object shape. Therefore, we investigate the possible use of a ferrofluid as an actuating component because of its fluidity and peculiar characteristics. A ferrofluid has the characteristics of a fluid and magnetic material; therefore, the fluid gathers around the source of a magnetic field and applies force to an object on it. In this paper, we verify the characteristics of the proposed system as well as the object manipulation. Through characteristic verification, the behavior of our system can be modeled, and the method of object transportation can be systematized.