Modulation of Magnetorheological Fluid Flow in Soft Robots Using Electropermanent Magnets

K. McDonald, L. Kinnicutt, A. M. Moran, and T. Ranzani, “Modulation of Magnetorheological Fluid Flow in Soft Robots Using Electropermanent Magnets,” in IEEE Robotics and Automation Letters, doi: 10.1109/LRA.2022.3147873
https://sites.bu.edu/ranzani-lab/file...



Researchers from Boston University’s Morphable Biorobotics Lab have developed a way to control soft robots using magnetorheological fluids.

Magnetorheological (MR) fluids are made of a suspension of iron particles in a carrier fluid, like water.

In the presence of a magnetic field, MR fluids solidify.

MR fluids have been used to control the inflation of soft fluidic actuators, but previous efforts have been binary in nature.

Now, fully modulated control is possible using electropermanent magnets.

An electropermanent magnet (EPM) can be electronically controlled like an electromagnet, but, like a permanent magnet, produces a steady magnetic field without consuming power.

By controlling a brief pulse of current, an EPM can have its field modulated to any value between zero and a maximum dictated by its materials.

The researchers used this effect to control the solidification of a flowing MR fluid and the pressure in an attached soft actuator.

In this way, devices with multiple degrees of freedom could be proportionally controlled in an electronic manner with as few external pressure lines as possible.

This was demonstrated using a two degree of freedom platform that could change its elevation and angle to any point in its workspace using only electrical stimulus to the EPMs.

The researchers hope this work could lead to more advanced onboard control methods for fluidically actuated soft robots, improving their autonomy and allowing them to more easily interact with the world around them.


Video By: Kevin J. McDonald
Boston University College of Engineering
Department of Mechanical Engineering
Morphable Biorobotics Lab