Robots have played an important role in the past few decades but their capabilities and usage are poised for exponential growth thanks to a whole new category of robots arriving on the scene: soft robotics.
Fundamentally, soft robots are exactly what they sound like, robots that are compliant in places where it’s most useful. And it’s this softness that makes the new soft robots more successful, interacting with everything from a strawberry to a human.There is no one definition, but all definitions include a category of robots that are not only made from compliant material but have biomimetic capabilities, qualities which make them more readily adaptable to working alongside humans and interacting with “soft” objects, such as food produce, the human body, and even manufacturing materials. The growth of soft robotics is opening up myriad opportunities and adding tremendous value due to their increased application.
Constructing a robot from compliant materials, such as elastomers or stretchy plastics, gives them a far greater ability to interact with objects less rigid than they are. Scientists speak of “compliance matching” or the idea that “materials that come into contact with each other should share similar mechanical rigidity in order to evenly distribute internal load and minimise interfacial stress concentrations,” according to Elveflow Plug & Play Microfluidics. Simply put, this means that traditional robots, with their hard, rigid nature do not typically interact well with humans. Soft robots are both made with softer materials and are adaptable to equalising their force relative to the object they are interacting with.
This extends beyond just a robot’s exterior casing. A problem with traditional robots is their inability to hold, grip or move objects less dense than they are. These robots either lack the ability to grip, or they grip so non-compliantly they crush whatever’s in their grasp.
For these reasons, hard robots lack the ability to interact effectively with real-world situations, whether it’s packaging soft materials, or interacting with humans in a medical scenario. Soft robotics, on the other hand, can interact more effectively and safely with humans, unknown objects and rough terrain – anything more compliant or non-linear.
In recent years, experts have fixed on three main advancements enabling the rise of soft robotics: smart materials, mathematical modeling of compliant systems, and fabrication technologies. The first two refer to advancements in either optics or mechanics, and the mathematical modeling that allows for nonlinear behaviors. Meanwhile, new fabrication technologies allow for the combination of hard and soft materials necessary for actuators, sensors and soft robotic casings.
Nature as the model for soft robotics
Biology itself seems to hold the answer to how to make robots more adaptable to their environment. As humans, when we step on a rock along a path we automatically respond to that change in our environment by compensating for that disruption. Our combination of a hard skeleton and soft tissue enables this fluidity of movement. In the same way, animals and insects with exoskeletons, or external shells (or their bones on the outside of their bodies) but that have soft tissue beneath also have this innate adaptability. Combining some robotic elements with the biomimetic traits found readily in nature has raised this study of “soft robotics,” or the ability to interact more effectively by adapting to changing situations the way nature does.
This not only opens up myriad use cases within production and industry, but also means humans and robots can interact more safely in the same workspace. Contact between a robot and a human can have dire consequences; contact between a human and soft robot delivers a much softer landing.
“Biomimicry” is the study of mimicking the dynamics found in nature and reproducing them outside of nature. Natural organisms have the ability to achieve smooth, fluid motion, such as earthworms, an octopus or an elephant’s trunk. This natural perfection, or adaptability to outside stimuli is difficult to program. Robots are typically programmed with a confined set of parameters. Soft robots “adapt” to changing situations by way of unknown outside stimuli.
Even plant cells respond to changes in the elements, producing hydrostatic pressure based on climactic forces. A plant’s shape and even its structure can change with pressure changes, and this concept is mimicked in soft robotics and used to devise pressure systems. This is only one such automatic instance in nature that the field of soft robotics is working to mimic.
Although endeavoring to mimic nature, soft robots still require one of three types of actuators to convert energy into motion. As Chloe Feast of the University of Pittsburgh’s Swanson School of Engineering explains in ‘The Applications and Benefits of Soft Robotics’, the first is pneumatics, whereby air is pumped into compartments through micro channels that allow the compartments to expand and contract to form specific shapes. The second are actuators , which are able to produce bending patterns in pressurised fluid-filled chambers. The third is voltage, which mimics muscles that expand and contract in response to the voltage applied.
The goal is for soft robotics to be able to sense and respond to changes in their environment the same way humans, plants and animals can. To take it even a step further, these soft robots are being programmed to be able to bypass their “brain” or electrical data center and respond organically to rough terrain or any other dynamic condition.
This capability of locomotion is why the field of soft robotics rose with advancements in materials and mathematical modeling before being viable. The third advancement – advanced materials combining hard and soft elements – had been the final technological gap, until fairly recently. Even soft robots require embedded “muscles” and soft electronics to power their movement, something unattainable until recent material advancements.
An early entrant to the study of soft robotics is Hod Lipson PhD, head of the Creative Machines Lab at Columbia University. The Creative Machines Lab is “interested in robots that create and are creative”. Comprised of researchers from engineering, computer science, physics, math and biology, this team’s work looks at “self-organisation and evolutionary phenomena . . .” and is deeply “inspired from biology”.
According to Lipson, his lab’s work deals with “encoding”, which is “essentially the blueprint of the design, analogous to DNA in biology…” which enables the “creation of more natural and life-like robots by trying to mimic nature and biology as much as possible.”
Going beyond the automotive factory floor
So why all the attention to soft robotics? The potential applications for this adaptable technology have far-reaching implications in medicine, disaster recovery, warehouse and distribution, agriculture and more.
Robots were first used in the automotive industry and remain its largest use case today. In fact, estimates are that 75% of the automotive industry currently uses some form of automation with robotics. Much of this is still in rigid robotics but robotic usage is expected to skyrocket once systems are in place for soft robots that are capable of safe interaction with humans.
The beauty of soft robots is that the limiting factors of traditional robots do not exist in soft robotics, so the boundaries for their use can be pushed in new directions. Soft robotics can be safely used side-by-side with humans in an operating room or on a factory floor. From shapeshifting robotic implants that deliver laser-activated drug delivery to patients, to the rehabilitation of stroke victims through the use of a soft robotic glove to restore patient dexterity, to robotic-assisted surgeries that allow for precision and even shapeshifting (to reach difficult areas of a patient’s anatomy), the uses in biomedical are astounding.
Risky tumor removal that requires extraction of a tumor and the affected surrounding tissue – but not the healthy tissue right up against it – is aided by the precision of a programmable robot. MRI scans can pinpoint tumor locations and transmit them to the robot. This means more precise extraction of the tumor and affected tissue.
Search-and-rescue missions can deploy soft robots to cover challenging environmental conditions to reach a victim and interact safely with the human, once there.
No less important is a soft robot’s ability to pick, handle and package delicate fruit in a way that doesn’t decrease its market value through bruising and rough handling. An estimated $13m worth fruit and vegetables was wasted in 2015 due to a lack of pickers. With soft robotics, growers who struggle to employ enough workers to harvest their crops have a whole new tool. This also extends to the packaging of frozen food items, a very difficult job to fill due to the environmental extremes a worker is subjected to.
Still, despite all the advancements in soft robotics, innovation and development are still in the early stages. Research facilities are busy tackling some of the most vexing problems still associated with maximising the efficacy of soft robotics, such as: actuators, pinching mechanisms, and the materials used to enable both soft and hard combinations.
This article is an excerpt from the white paper ‘Robotics Inspiration Guide: 3D Printing Your Way From Idea to Application’ from Objective 3D. To read the paper in full, visit: http://tinyurl.com/y4gfvxhu.