Low-voltage actuator could be the future of ‘soft’ robotics

By Warren Miller, contributing writer

When you think about robots, you probably envision rigid, metallic, humanoid figures repeating things like “Danger, Will Robinson!” or “Resistance is futile” in computer-like voices. In truth, recent advances in robotics have led to machines capable of assisting with surgeries, checking you into a hotel, and even cooking simple meals. Perhaps even more innovative is the form robots are taking known as “soft robotics,” which are complex mechanisms that can (in some cases) bend, twist, and stretch like a human muscle.

Robotic movement is based on actuators, which are mechanical components that are triggered by a control signal. The signal itself can be created by electric, hydraulic, or pneumatic energy — the actuator converts the energy from the control signal into movement. Soft robotic actuators, conversely, have relied on air flow or heat-differential, slow processes that severely limit the sorts of operations that soft-robotic systems can perform. However, a research team from the University of California at Santa Barbara (USCB) believes that they’ve married the electrically powered actuator commonly found in traditional robotic systems with their softer counterparts.

“An interesting biological analog to the actuator described in our new work might be a fast twitch muscle,” said Von Visell, co-author of a paper on the soft-robotics actuator and a professor of electrical and computer engineering at UCSB. “In this project, we wanted to see how far we could push the idea of having very fast, low-voltage actuation within a fully soft-robotic paradigm.”

Image source: UCSB.

Just a few millimeters in size, the new actuator is faster than its soft-robotics predecessors and operates on very low voltage. Casings made of polymer fibers and magnetic polymer composites house liquid-metal conductors, forming three-dimensional soft structures that mimic standard electromagnetic motors. The materials were specifically designed to possess high thermal conductivity, another factor in their improved performance.

The team tested the actuator by creating a tiny gripping device, similar to the ones commonly found in arcades and bowling alleys used to grab toys and prizes at the cost of 50 cents per attempt. The gripper opened and closed in milliseconds.

Soft robotics could be used in many forms of wearable technology, as well as virtual- and augmented-reality systems, particularly in the area of haptics. Faster actuators mean faster response time, which could result in better user experiences without the need for bulky and clumsy technology.

Doctors have been using robotic instruments to perform certain procedures for some time; the capability to utilize soft-robotic systems in lieu of more rigid mechanisms could provide opportunities for finer control and more subtle operations. “The horizon is wide open,” said Visell.