Mar 19 2020
A new soft robot developed by researchers from UC resembles balloon art on steroids. It is a pneumatic, shape-changing robot with the ability to navigate its environment without the need to tether to a stationary power source.
Elliot Hawkes. Image Credit: Matt Perko.
The soft robot, developed by UC Santa Barbara mechanical engineering professor Elliot Hawkes’ group, is a crucial step forward to bring soft robots to human surroundings, where their features are particularly ideal for interaction with and around people.
“The main challenge that we’re trying to address is to make a human-scale soft robot,” stated Hawkes, whose study appears in the Science Robotics journal.
A majority of the soft robots developed so far are small in sizes and usually tethered to the wall for compressed air or power, Hawkes explained. But what if it is possible to develop a soft robot powerful and huge enough to carry out human-scale interactions and be autonomous enough to navigate various unstructured surroundings like disaster zones?
Thus came the isoperimetric soft robot, an approximately four-foot-tall pneumatic robot that can move by bending its soft, air-filled fabric tubes, while retaining its perimeter constant.
The idea is that you can change the shape of the soft robot by using simple motors that drive along the tubes, instead of using the slow, inefficient pumps that are normally used.
Elliot Hawkes, Professor, Department of Mechanical Engineering, UC Santa Barbara
Hawkes performed the study while he was at Stanford University.
In fact, the isoperimetric robot is a blend of ideas obtained from three different robotic fields—truss robots, collective robots, and soft robotics—that can offer new capabilities together.
The robot’s soft fabric tubes enable it to move on irregular surfaces and deform as required, and are lightweight yet strong. Also, the motors can be linked to one another through three-degree-of-freedom universal joints to make truss-like structures that can bear weight and enable locomotion in three dimensions.
Furthermore, the motor “nodes” that enable the tubes to bend are themselves simple, compact collective robots that jointly roll through the fabric tube and squeeze to develop joints of differing angles.
Probably, the most remarkable feature of the robot is that it doesn’t need deflation and inflation to move, thereby eliminating the need for a connection to a bulky, unwieldy, onboard pump or an external, stationary source of air. Small batteries are used to drive the motors.
We were looking at ways to make it untethered, and we realized that we didn’t need to pump air in and out; what we really needed to do was to move the air around. It turns out that when you have air, even at relatively low pressure, there are huge forces that it applies.
Elliot Hawkes, Professor, Department of Mechanical Engineering, UC Santa Barbara
In fact, this was one of the major design challenges faced by the team. A lot of engineering was employed to create the nodes that roll together with the tube and pinch to form joints.
Hawkes added that the benefit in this concept is that the robot’s functioning is smoother and rapid than it would be if it had to deflate and inflate during this process.
The scientists visualize several applications for a robot of this kind. For example, in the case of a collapsed building, the robot would be able to crawl flat into confined spaces and rebuild into a three-dimensional truss to make space and support weight.
In the case of the planetary expedition, the robot packs light and can navigate unpredictable terrain. It has the capability to pick up and even handle loads. Its soft nature enables it to operate beside humans. Thanks to its simple, modular design, students and other robot-builders can make different robots in various shapes and for different purposes.
As a combination, the freedom of movement, size, utility, and strength of the robot in real-world scenarios symbolize the kind of focus that Hawkes and his team consider will be beneficial. According to Hawkes, studies on soft robots are exciting and new, and have become more prevalent now.
But as a field, we need to think critically about what contributions each research project offers, what problems it solves or how it advances the field, as opposed to just making another cool gizmo.
Elliot Hawkes, Professor, Department of Mechanical Engineering, UC Santa Barbara
The study was also performed by Nathan S. Usevitch and Zachary M. Hammond (lead authors); and Allison Okamura, Mac Schwager, and Sean Follmer, all from Stanford University.