Enhancing Soft Robotics with ‘Embodied Energy’ Opens New Possibilities

Robotics is a fast-growing market, projected to expand from $94.54 billion in 2024 to surpass $372.59 billion by 2034. 

Industrial robots are currently leading this growth. Today, more than 3.4 million industrial robots are working to make our lives easier. Industrial companies are also planning to invest 25% of their capital in industrial automation over the next five years.

As robotics continues to gain traction, a subfield of robotics is also gathering the attention of researchers. As demand for robots increases in applications beyond industrial automation, the subfield of soft robotics is gaining a growing interest.

These robots copy the locomotion mechanisms of soft and flexible bodies existing in nature, such as snakes, earthworms, eels, octopuses, and others. 

Soft robotics take inspiration from the biological structures of these soft bodies for their smooth and complex motion. Instead of using hard, metallic components like traditional robots, soft robots are typically made out of pliable materials like gel and rubber. This allows them to adapt to complex environments and interact with humans safely.

For their actuation, a number of different ways are utilized, such as heat stimuli, electrical signals, and air pressurization, among others. The sources of their activation are usually found outside of the robot’s bodies and control their movements.

These robots offer the benefits of adaptability and enhanced safety. The use of flexible and lightweight material particularly makes these machines suitable for direct human interaction as it reduces the risk of injury. This makes them highly beneficial in applications such as healthcare and wearable technology.

Having flexible joints and soft grippers enables these robots to bend, twist, and stretch easily. The ability to perform biological motions makes them usable in tasks that may not be safe for humans or require a high degree of control. Their structural flexibility and dexterity also make them idle for handling fragile objects and performing other delicate tasks.

But of course, soft robots also face challenges such as limited strength, low precision, low durability, difficulty in manufacturing and scaling, and the need for advanced algorithms and extensive sensing systems.

However, given that the capability of soft robots closely matches soft biological organisms, they are a promising feature in a variety of fields such as healthcare, agriculture, search and rescue, and space exploration.

Several promising soft robots have already been developed. For instance, Harvard’s tentacle robot, whose jellyfish-like soft gripper can gently grasp fragile objects by mimicking the mechanics of curly hair.

In the healthcare field, K-FLEX from the Korea Advanced Institute of Science and Technology has the capability to perform scar-free endoscopic surgery, and MIT’s bionic heart can help medical professionals study cardiovascular diseases and determine the best course of treatment for patients.

Soft robots are also being utilized to explore oceans. A few years ago, Chinese researchers presented a self-powered soft robot that can reach the deepest point — the Mariana Trench. As for space expiration, NASA-sponsored burrowing soft robots can navigate sandy terrain and may one day be sent to explore the moons of Jupiter.

As research surrounding soft robots advances, they can even be expected to replace rigid robots in various applications. 

The Evolution of Soft Robot Species

A new study from Cornell Engineering has presented an untethered terrestrial crawling robot with an integrated modular power system throughout its soft body. 

Before creating this worm robot, the Lab built a jellyfish robot in collaboration with the Archer Group of Cornell Engineering. Both are direct descendants of an aqueous soft robot that was presented six years ago. 

So, back in 2019, Cornell University researchers presented a paper¹ called “Electrolytic vascular systems for energy-dense robots.” The system, which emulated redox flow batteries, combined the functions of hydraulic force transmission, actuation, and energy storage into one design that increased the robot’s energy density to enable operation for as many as 36 hours. 

For this, the researchers took inspiration from a lionfish, which uses undulating fanlike fins to glide through coral-reef environments.

At the time, the researchers noted that “this use of electrochemical energy storage in hydraulic fluids could facilitate increased energy density, autonomy, efficiency, and multifunctionality in future robot designs.”

A few months ago, a new paper², “The multifunctional use of an aqueous battery for a high capacity jellyfish robot,” was released. This time around, an RFB was formed into the shape of a jellyfish, which makes a multifunctional use of energy. 

Jellyfish are mostly made of a substance called “mesoglea,” which serves as an internal skeleton. This material makes jellyfish’s body elastic and helps reinstate its shape after it deforms due to muscle contraction. The mesoglea is made up of fibrillin-containing microfibrils that the jellyfish uses to power its muscle in addition to allowing it to move and feed.

The robot was powered solely by RFBs with increased volumetric and areal energy density, resulting in a long operational lifetime for UUVs composed of mainly liquid, which is electrochemically energy-dense.

Now, the research³ has further evolved, much like how terrestrial life did, driven by battery development and design.

According to Rob Shepherd, professor of mechanical and aerospace engineering, who led the previous one and this new project:

“This is how life on land evolved. You start with the fish, then you get a simple organism supported by the ground. The worm is a simple organism, but it has more degrees of freedom.”

The same “robot blood,” i.e., the hydraulic fluid that stored energy and powered previous robots’ applications, is also sustaining the new species of robot. This time around, though, researchers have further improved the design to achieve greater battery capacity and power density.

The jellyfish, Shepherd noted, has much more capacity for its weight. This increased the duration of time that robot fish could travel, which was longer than that of the actual fish. Now, their first above-ground version is the worm, which gets buoyantly supported when underwater and doesn’t need a skeleton, which means it doesn’t need to be rigid.

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Embodied Energy Powering Soft Robots

As demand for increased agility in robotics grows, so will their complexity. This means an increase in densities of sensing and degrees of freedom (DoF), which is the independent movement of an object.

As a result, the power consumption of the robots is likely to increase as well, which makes energy capacity an important factor to be considered.

This is where embodied energy comes into the picture. It is a design strategy that improves the system level of energy density through the multifunctional use of embedded power sources. This approach basically includes power sources in the machine’s body, which reduces its cost and weight.

The modelar worm robot built by the Organic Robotics Lab and their jellyfish both showcase the benefits of this ’embodied energy.’ 

By embodying the energy stored in batteries into an integral part of the robot’s structure and machinery, the researchers have been able to achieve better results. The study noted:

“Embodying a power source into motor driven-tendon actuator modules provides an artificial muscle unit composable into robots capable of long duration, useful work.”

Both robots feature a redox flow battery (RFB), which is a type of electrochemical system that stores energy provided by two chemical components dissolved in liquid. 

In the case of the jellyfish-shaped robot, the RFB was built with a tendon. When the tendon is pulled, it changes the shape of the bell and pushes the creature upward, sinking back down when the bell relaxes. 

More importantly, the jellyfish robot features a pair of redox batteries: zinc iodide (ZnI2) and zinc bromide (ZnBr2). Bromine was added to the iodine in one of the batteries to enhance ion transport, which increased the battery capacity and power density. As a result, the jellyfish robot was faster and more agile, having an operational lifetime of about 90 minutes.

Now, to evade the problem of dendrite buildup on the electrical substrates of the batteries, which obstructs their charging and discharging, the researchers made use of graphene. Applying graphene allowed them to better match the crystal planes and more even plating of the zinc. 

The worm robot features a compartmentalized design. The body of the worm is a series of interconnected pods, each of which contains a motor and tendon actuator to allow the worm to compress and expand its shape. Each pod also contains a pile of anolyte pouches submerged in a catholyte.

An essential element of the design was using a dry-adhesion method to automatically bond Nafion separators to the worm’s silicone-urethane copolymer body. The separator keeps the anolytes and catholytes apart while allowing the charge to move between them, which then drives electrons through the motor.

“There are a lot of robots that are powered hydraulically, and we’re the first to use hydraulic fluid as the battery, which reduces the overall weight of the robot, because the battery serves two purposes, providing the energy for the system and providing the force to get it to move. So then you can have things like a worm, where it’s almost all energy, so it can travel for long distances.”

– Shepherd

Upon testing the worm robot, the researchers found that it can inch along the ground as well as move up and down a vertical pipe. While the robot worm can navigate an enclosed, curved path and climb up and down, it is pretty slow, though still faster than other hydraulically powered worm bots. On a single charge, the worm takes 35 hours to travel 105 meters.

The worm, according to researchers, can find its application in the exploration of a constrained environment like long and narrow passageways and possibly conducting repairs. As for the jellyfish, its use case can be found in ocean exploration. 

Supported by the Office of Naval Research and the Basic Energy Sciences Program of the Department of Energy, this research is just the beginning, as the focus of their future work will be on a fully liquid RFB. The study noted that the polysulfide-iodide battery, with its high-energy density and low cost, in particular, shows promise for soft robotics applications.

Ultimately, the team aims to build high-capacity, embodied energy robots. These future robots will also have skeletons and can even walk, resulting in robots resembling humans.

“An imperfect organism. But still doing pretty good.”

– Shepherd

Relevant Companies

Now, let’s take a look at a couple of publicly-listed companies that are helping advance the robotics field. 

1. iRobot Corporation (IRBT -1.43%)

A global consumer robot company, iRobot is involved in the designing, building, and sales of durable robots. Its products include Roomba, Braava, and Root. iRobot has sold tens of millions of its robots worldwide.

With a market capitalization of $231 million, iRobot stocks are currently trading at $7.59, down 2.45% YTD. Its EPS (TTM) is -4.60, while its P/E (TTM) ratio is -1.64.

Most recently, the company reported preliminary financial results for the fourth quarter of 2024, as per which it is expecting a revenue of $171 million and a GAAP operating loss of $59 million. It also expects its cash and cash equivalents at the end of fiscal 2024 to be about $134 million.

The results, CEO Gary Cohen said, “reflect higher-than-anticipated seasonal promotional spending to stimulate sell-through prior to our 2025 new product launches.” He also shared that iRobot has “fundamentally changed the way we innovate, develop and build our robots,” and that its planned product launches “that are designed to excite consumers with feature-rich robots and improve the consumer product experience” are on track to release this year.

2. Teradyne (TER -3.3%)

A global supplier of automated test equipment and robotics solutions, Teradyne operates through four segments whose focus is semiconductors, wireless products, systems covering storage, aerospace, and circuit board, and robotics, which cover robotic arms, autonomous mobile robots, and advanced robotic control software.

The company has deployed more than 80,000 advanced robotic systems worldwide and has invested over $700 million in advanced robotics and automation. Teradyne’s MiR robots streamline internal transportation and material handling, while its cobots support a wide range of applications. Its automation solutions enable businesses to enhance their operational efficiency by integrating the power of machines.

With a market capitalization of $18.74 billion, Teradyne stocks are currently trading at $116, down 8.61% YTD. Its EPS (TTM) is 3.32, while its P/E (TTM) ratio is 34.68. The company pays a dividend yield of 0.42%.

For Q4 of 2024, the company reported a revenue of $753 million, of which $98 million was from Robotics while the rest was from the semiconductor segment. Its GAAP net income for the quarter came in at $146.3 million or $0.90 per diluted share.

CEO Greg Smith attributed this growth to strong AI compute and related memory while Mobile and Auto/Industrial surpassed expectations. Revenue acceleration is expected for this year, with Teradyne planning to strategically realign its Robotics business to enhance customer experience and drive operational efficiency.

3. Zimmer Biomet (ZBH -1.37%)

A global medical technology company, Zimmer Biomet is involved in biologics, sports medicine, extremities, trauma products, surgical products, and a suite of robotic technologies that utilize data, data analytics, and AI. 

With a market capitalization of $22 billion, Zimmer Biomet stocks are currently trading at $110.10, up 4.72% YTD. Its EPS (TTM) is 5.25, while its P/E (TTM) ratio is 21.07. The company pays a dividend yield of 0.87%.

For Q3 2024, the company reported net sales of $1.824 billion, which was an increase of 4% over the prior year period, while its net earnings came in at $249.1 million. Diluted earnings per share for the quarter were $1.23, while adjusted diluted earnings per share were $1.74. Following this “strong performance,” CEO Ivan Tornos said they will continue to advance its “mission to help millions of people alleviate pain and improve their quality of life.” 

During this period, the company acquired OrthoGrid Systems, a medical technology company focused on AI-driven surgical guidance systems for total hip replacement. It is now also set to acquire Paragon 28, a medical device company, in a $1.1 billion deal for treating foot and ankle diseases.

Conclusion

With demand for automation and efficiency rising, so is the popularity of robotics. Against this strong growth backdrop, the subfield of soft robotics is seeing a lot of innovation, unlocking new applications in healthcare, exploration, and industrial automation. 

The evolution of soft robotics—combining adaptability inspired by living organisms with embodied energy—carries the potential to finally overcome the longstanding limitations of durability and energy efficiency. As researchers, supported by government initiatives, continue refining robot design and multifunctional power sources, these machines steadily becoming a reality, improving accessibility, efficiency, and safety.

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