Newly-Designed Soft Dynamic Actuators Could Help Drive the Next Generation of Soft Robots

A team of researchers at Harvard University and the Massachusetts Institute of Technology (MIT) have unveiled a key piece in the puzzle towards next-generation soft robotics: an electrically-driven soft valve designed for use with hydraulic actuators.

"Today's rigid regulation systems considerably limit the adaptability and mobility of fluid-driven soft robots," explains Robert J. Wood, professor of engineering and the paper's senior author. "Here, we have developed soft and lightweight valves to control soft hydraulic actuators that open up possibilities for soft on-board controls for future fluidic soft robots."

"These soft valves have a fast response time and are able to control fluidic pressure and flow rates that match the needs of hydraulic actuators," adds first author Siyi Xu. "These valves give us fast, powerful control of macro-and small-scale hydraulic actuators with internal volume ranging from hundreds of microliters to tens of milliliters."

Soft valves aren't necessarily new, but existing designs can't handle the pressure or flow rates to adequately drive a hydraulic actuator. The team's version, electrically-powered devices dubbed dynamic dielectric elastomer actuators or DEAs, offer vastly improved power density, low weight, and when combined with a soft channel can be used as soft valves for fluidic control in soft robotics.

"This compact and light-weight DEA valve is capable of unprecedented electrical control of hydraulic actuators," Xu claims, "showing the potential for future on-board motion control of soft fluid-driven robots."

The team is hoping the valves will find a home in everything from biologically-inspired soft robots to grippers, surgical robots, assistive and therapeutic devices, and more.

The work has been published under closed-access terms in the Proceedings of the National Academy of Sciences (PNAS).