Nav: Home

These new soft actuators could make soft robots less bulky

October 11, 2019

Engineers at the University of California San Diego have developed a way to build soft robots that are compact, portable and multifunctional. The advance was made possible by creating soft, tubular actuators whose movements are electrically controlled, making them easy to integrate with small electronic components.

As a proof of concept, engineers used these new actuators to build a soft, battery-powered robot that can walk untethered on flat surfaces and move objects. They also built a soft gripper that can grasp and pick up small objects.

The team, led by UC San Diego mechanical and aerospace engineering professor Shengqiang Cai, published the work Oct. 11 in Science Advances.

A problem with most soft actuators is that they come with bulky setups. That's because their movements are controlled by pumping either air or fluids through chambers inside. So building robots with these types of actuators would require tethering them to pumps, large power sources and other specialized equipment.

In the current study, UC San Diego engineers created soft actuators that are controlled with electricity. "This feature makes our tubular actuators compatible with most low-cost, commercially available electronic devices and batteries," Cai said.

The actuators are made from a type of material used for artificial muscles in robots, called liquid crystal elastomers. They are composed of liquid crystal molecules embedded in a stretchy polymer network. What's special about these materials is they change shape, move and contract in response to stimuli such as heat or electricity--similar to how muscles contract in response to signals from nerve cells.

To construct each actuator, engineers sandwiched three heating wires between two thin films of liquid crystal elastomer. The material is then rolled into a tube, pre-stretched and exposed to UV light.

Each heating wire can be controlled independently to make the tube bend in six different directions. When an electric current is passed through one or two of the wires, it heats up part of the tube and makes it bend in the direction of those wires. When a current is sent through all three wires, the entire tube contracts, shortening in length. When the electricity is turned off, the tube slowly cools down and returns to its original shape.

"Using an externally applied electrical potential makes it easy to program the position of each tubular actuator," said first author Qiguang He, a mechanical and aerospace engineering Ph.D. student at the UC San Diego Jacobs School of Engineering.

Combining multiple actuators together enabled engineers to build different types of soft robots. They built an untethered, walking robot using four actuators as legs. This robot is powered by a small lithium/polymer battery on board. They also built a soft gripper using three actuators as fingers.

Each robot has an on-board microcontroller in which engineers programmed a sequence of electrically controlled motions for the actuators. This allows the robots to move independently.

The team is now working on making soft actuators that can move faster. The current actuators take about 30 seconds to fully bend and contract, and up to four minutes to return to their original shapes. That's because the material takes a bit of time to fully heat up and cool down. The ultimate goal is to make actuators that can contract and relax as quickly as human muscles, He said.
-end-
Paper title: "Electrically controlled liquid crystal elastomer-based soft tubular actuator with multimodal actuation." Co-authors include Zhijian Wang, Yang Wang, Adriane Minori and Michael T. Tolley, UC San Diego.

This work was supported by the Office of Naval Research (grant N00014-17-1-2062) and the National Science Foundation (grant CMMI-1554212). This work was performed in part at the San Diego Nanotechnology Infrastructure (SDNI) at UC San Diego, a member of the National Nanotechnology Coordinate Infrastructure, which is supported by the National Science Foundation (grant ECCS-1542148).

University of California - San Diego

Related Robots Articles:

Darn you, R2! When can we blame robots?
A recent study finds that people are likely to blame robots for workplace accidents, but only if they believe the robots are autonomous.
Robots need a new philosophy to get a grip
Robots need to know the reason why they are doing a job if they are to effectively and safely work alongside people in the near future.
How can robots land like birds?
Birds can perch on a wide variety of surfaces, thick or thin, rough or slick.
Soft robots for all
Each year, soft robots gain new abilities. They can jump, squirm, and grip.
Robots activated by water may be the next frontier
Columbia University scientists have developed material that can drive mechanical systems, with movements controlled by a pattern set into the design.
The robots that dementia caregivers want: robots for joy, robots for sorrow
A team of scientists spent six months co-designing robots with informal caregivers for people with dementia, such as family members.
Faster robots demoralize co-workers
A Cornell University-led team has found that when robots are beating humans in contests for cash prizes, people consider themselves less competent and expend slightly less effort -- and they tend to dislike the robots.
Increasing skepticism against robots
In Europe, people are more reserved regarding robots than they were five years ago.
Humans help robots learn tasks
With a smartphone and a browser, people worldwide will be able to interact with a robot to speed the process of teaching robots how to do basic tasks.
Robots as tools and partners in rehabilitation
Why trust should play a crucial part in the development of intelligent machines for medical therapies.
More Robots News and Robots Current Events

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Rethinking Anger
Anger is universal and complex: it can be quiet, festering, justified, vengeful, and destructive. This hour, TED speakers explore the many sides of anger, why we need it, and who's allowed to feel it. Guests include psychologists Ryan Martin and Russell Kolts, writer Soraya Chemaly, former talk radio host Lisa Fritsch, and business professor Dan Moshavi.
Now Playing: Science for the People

#538 Nobels and Astrophysics
This week we start with this year's physics Nobel Prize awarded to Jim Peebles, Michel Mayor, and Didier Queloz and finish with a discussion of the Nobel Prizes as a way to award and highlight important science. Are they still relevant? When science breakthroughs are built on the backs of hundreds -- and sometimes thousands -- of people's hard work, how do you pick just three to highlight? Join host Rachelle Saunders and astrophysicist, author, and science communicator Ethan Siegel for their chat about astrophysics and Nobel Prizes.