Researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and Caltech have developed new soft robotic systems that are inspired by origami. These new systems are able to move and change shape in response to external stimuli. The new developments bring us closer to having fully untethered soft robots. The soft robots that we possess today use external power and control. Because of this, they have to be tethered to off-board systems with hard components.
The research was published in Science Robotics. Jennifer A. Lewis, a Hansjorg Wyss Professor of Biologically Inspired Engineering at SEAS and co-lead author of the study, spoke about the new developments.
“The ability to integrate active materials within 3D-printed objects enables the design and fabrication of entirely new classes of soft robotic matter,” she said.
The researchers used origami as a model to create multifunctional soft robots. Origami, through sequential folds, is able to change into multiple shapes and functionalities while staying in a single structure. The research team used liquid crystal elastomers that are able to change their shape when exposed to heat. The team utilized 3D-printing to get two types of soft hinges. Those hinges fold depending on the temperature, and they can be programmed to fold into a specific order.
Arda Kotikan is a graduate student at SEAS and the Graduate School of Arts and Sciences and the co-first author of the paper.
“With our method of 3D printing active hinges, we have full programmability over temperature response, the amount of torque the hinges can exert, their bending angle, and fold orientation. Our fabrication method facilitates integrating these active components with other materials,” she said.
Connor McMahan is a graduate student at Caltech and co-first author of the paper as well.
“Using hinges makes it easier to program robotic functions and control how a robot will change shape. Instead of having the entire body of a soft robot deform in ways that can be difficult to predict, you only need to program how a few small regions of your structure will respond to changes in temperature,” he said.
The team of researchers built multiple soft devices. One of these devices was an untethered soft robot called “Rollbot.” It starts as an 8 centimeters long and 4 centimeters wide flat sheet. When it is in contact with a hot surface of around 200°C, one set of the hinges folds and shapes the robot into a pentagonal wheel.
On each of the five sides of the wheel, there are more sets of hinges that fold when in contact with a hot surface.
“Many existing soft robots require a tether to external power and control systems or are limited by the amount of force they can exert. These active hinges are useful because they allow soft robots to operate in environments where tethers are impractical and to lift objects many times heavier than the hinges,” said McMahan.
This research that was conducted focused solely on temperature responses. In the future, the liquid crystal elastomers will be studied further as they are also able to respond to light, pH, humidity, and other external stimuli.
“This work demonstrates how the combination of responsive polymers in an architected composite can lead to materials with self-actuation in response to different stimuli. In the future, such materials can be programmed to perform ever more complex tasks, blurring the boundaries between materials and robots,” said Chiara Daraio, Professor of Mechanical Engineering and Applied Physics at Caltech and co-lead author of the study.
The research included co-authors Emily C. Davidson, Jalilah M. Muhammad, and Robert D. Weeks. The work was supported by the Army Research Office, Harvard Materials Research Science and Engineering Center through the National Science Foundation, and the NASA Space Technology Research Fellowship.
Matt Carlson, VP Business Development at WiBotic – Interview Series
Matt Carlson is the Vice President of Business Development at WiBotic Inc, a company that provides reliable wireless power solutions to charge aerial, mobile and aquatic robot systems.
Why are wireless charging solutions so important to the future of robotics?
Robots need the ability to autonomously charge for most applications. It simply isn’t cost effective to hire a staff of workers to manage battery charging or battery swapping. However, most autonomous charging today is done using docking stations that require physical mating of electrical contacts.
This requires very precise navigation into the charging dock which is difficult to program and is not always reliable. Failing to properly align the contacts can mean a missed charging cycle and robot downtime. Contact based stations will also wear out over time, or the contacts may become dirty or corroded – again resulting in inconsistent charging. Finally, robot OEMs use a wide range of electrical contact types, making it nearly impossible to have a single charging station that can charge any robot.
Wireless systems have none of these issues. WiBotic systems offer several centimeters of alignment tolerance, so it’s not necessary to have an extremely precise navigation stack. Because the antennas can be fully sealed to the elements and don’t make physical contact with one another, wireless systems are also highly reliable and can handle an unlimited number of charge cycles. Finally, as robot use grows, most companies will employ more than one type of robot. Rather than having a wall or room dedicated to many different charging docks, a single wireless charging station can recharge any robot that is retrofitted with a simple receiver antenna, saving money and space.
Wibotic’s initial focus was on powering medical devices, what was the reason to pivot towards robots, drones, and Autonomous Underwater Vehicles (AUVs)?
WiBotic’s two founders, Ben Waters and Josh Smith, did indeed focus on wireless power for medical devices during much of their research at the University of Washington. Their technology increased the range and reliability of wireless power, which were both critical for the medical market. However, when Ben received his PhD and founded WiBotic, the company immediately focused on robotics as its primary market. This was based on demand from the robotics industry.
Robot and drone OEMs and end-users recognized the benefits of WiBotic technology in terms of power level and range when compared with other wireless systems. They were also beginning to struggle with the deployment of contact-based chargers for large fleets of robots and were looking for more reliable solutions.
For the drone market, contact based charging is a non-starter in most cases since drones operate outdoors (mostly) where water becomes an issue with any physical electrical contacts. And, of course, underwater applications also benefit from the fully sealed nature of wireless power.
What are the power transfer technologies being used?
WiBotic uses elements of both electrical induction and magnetic resonance for power transfer. These two methods are relatively well proven at a wide range of power levels. What sets WiBotic apart is our ability to manage the connection (technically the impedance) between antennas in real time. We call this Adaptive Impedance Matching.
One of the biggest challenges with wireless power, especially for robotics, is that the electrical environment is constantly changing. If the robot docks in a slightly different position, if it’s internal electronics turn on and off during charging, and as the battery itself charges up, the impedance between the transmit and receive sides of the system changes. This can dramatically affect efficiency and range. Our AIM technology constantly monitors changes in impedance so we can maintain efficiency and power levels, even as all of those other elements in the system are changing.
Could you discuss the efficiency of the units, such as how much power is lost during power transmission?
For WiBotic’s 250-300 Watt systems we have an end-to-end efficiency level of between 70% and 80%. This represents the full system efficiency from the input to our transmitter all the way to the output to the battery. The actual antenna-to-antenna portion of that equation is about 95% efficient, but there are losses in the transmitter circuitry and also in the battery charging circuitry. That last part is important to note since even a very well designed “plug in” battery charger is typically only around 90-95% efficient.
Using a wireless system like ours therefore results in about 10% less efficiency than the status quo of contact based charging.
What are the distance constraints with how close the robotic unit needs to be near the power source?
This depends on the size of the antennas used. Our standard transmitter antenna is 20cm in diameter and the receiver antenna is 10cm in diameter. With those antenna sizes, we allow for 5cm of face-to-face air gap between antennas and up to 5cm of side-to-side offset from a concentric position (so 10 total cm of side to side range).
Unlike other wireless power systems, and due to our AIM technology, we deliver full power to the battery at any point within that range. Ranges can be increased by increasing the diameter of the antennas. Because our antennas are relatively simple PCBAs (which are also very thin and lightweight) we’re able to modify and produce custom versions of them relatively inexpensively for customers who prefer a different size.
Are multiple robots able to use the same charging station?
Absolutely! Only one robot can charge at a wireless charging station at a time, but entire fleets of diverse robots can all share the same charging station (or set of charging stations). This is possible because, unlike most contact based chargers, the transmitter station is not sending out a specific voltage and current level. Instead it is sending wireless power at a designated frequency. Our Onboard Charger, installed on the robot, then converts that wireless energy into the specific voltage and current needed by that vehicle.
We support batteries from 0-60V and current levels from 0-30A with our current product line.
Could you discuss some of the power optimization software that is currently offered?
Our wireless power hardware ships with a web-based GUI that allows customers to configure the system for a wide range of parameters. For instance, users can choose to charge to the typical “100% charge” level for a particular battery. But if they do this every time, they may not get as many charge cycles out of the battery. So if 100% charge isn’t needed, the maximum voltage level can be adjusted downward to extend battery lifespan.
Similarly, if the battery is always charged with the maximum current (amps) it’s lifespan will be reduced. Using our GUI and APIs, users can actually proactively schedule charging so they charge as fast as possible when the robot needs to get back into service, or more slowly when they know they have more time (overnight for example). These configurability and battery optimization features are available with our standard GUI and by using our APIs.
We also offer a new software product that allows users to map and then aggregate charging information from across and entire fleet of WiBotic transmitters and receivers. This allows robots to know when and where charging stations are available to help them maximize uptime. It also allows detailed reporting on the charging performance of batteries over time, helping identify battery issues and optimizing power delivery across the entire fleet. These features become particularly useful if the end-user is able to implement opportunity charging schemes, where robots are charging many times per day for shorter periods of time, rather than leaving service for several hours at a time for charging.
Offering wireless power to Autonomous Underwater Vehicles (AUVs) seems like it would be extremely challenging, could you discuss this?
Yes, there are definitely many challenges with underwater applications. From a power transfer perspective a couple centimeters of saltwater will attenuate power transfer by about 50%, so it will take longer to charge the same sized batteries underwater than it would in air.
The antenna range is also more restricted for that same reason, which means the UAV must have very good navigation to successfully find and dock at the charging station. This is usually aided by some sort of physical alignment device that directs the UAV into the charging station and helps to align the antennas.
The benefit of wireless power underwater however, is that the antennas can be fully potted or sealed. WiBotic systems are currently operating at the MBARI MARS research station off the coast of Monterey, CA at a depth of nearly 3000ft. In that case, the transmitter and receiver electronics are housed in 1atm pressure bottles, but electronics can also be designed for oil filled enclosures to withstand even greater depth.
WiBotic continues to work with the DoD, various universities, non-profits and commercial partners to expand the use of our systems underwater, but it is definitely a challenging environment!
WiBotic has recently announced equipment authorization from the Federal Communications Commission (FCC) for its high power transmitters and receivers. These products are the first systems – operating at up to 300 Watts – to receive FCC approval for use in mobile robots, drones, and other industrial devices. Why is this important and what does this mean for the future of robotics and drones?
As the robotics industry continues to grow, OEMs and robot end-users are facing an increasing level of regulation and stricter safety requirements. It’s important for our customers to know that WiBotic products, as a component within their larger robotic solutions, will meet those regulatory requirements. In short, it allows robot and drone manufacturers to focus on additional features and functionality for end-users rather that dealing with certification questions. This will let them deploy larger fleets faster than would otherwise be possible.
Is there anything else that you would like to share about Wibotic?
Because most people think of the physical antennas and circuit boards when they think of wireless power, the immense amount of work we have put into our software and firmware is often overlooked. In many ways, it is the advanced firmware we’ve developed that allows our hardware to perform at such useful ranges and power levels.
We’re also continuing to add to our fleet power optimization software capabilities to allow for even greater analysis and benchmarking of the use of power and durability of batteries across a wide range of robotic applications.
Thank you for the great interview, readers who wish to learn more should visit at WiBotic Inc, or read about how WiBotic Received an Industry-First FCC Approval for High Power Wireless Charging of Robots & drones.
WiBotic Receives Industry-First FCC Approval for High Power Wireless Charging of Robots
WiBotic, a leader in advanced wireless charging and fleet energy management solutions for the rapidly expanding ecosystem of aerial, mobile and marine robots, today announced it received equipment authorization from the Federal Communications Commission (FCC) for its high power transmitters and receivers. Providing up to 300 watts of wireless power, these products are the first systems to receive FCC approval for use in mobile robots, drones, and other devices with larger batteries.
“FCC approval is not only an accomplishment for our team but also for our customers and the industry,” said Ben Waters, WiBotic CEO. “Previously only low power cell phone and small electronics chargers or very high power electric vehicle chargers were approved for widespread use. WiBotic is now providing a solution that lets the entire automation industry take advantage of the wireless power revolution.”
Why it Matters
When asked why this important to the future of drones and robotics technology, Matt Carlson the VP business development stated the following: “As the robotics industry continues to grow, OEMs and robot end-users are facing an increasing level of regulation and stricter safety requirements. It’s important for our customers to know that WiBotic products, as a component within their larger robotic solutions, will meet those regulatory requirements. In short, it allows robot and drone manufacturers to focus on additional features and functionality for end-users rather that dealing with certification questions. This will let them deploy larger fleets faster than would otherwise be possible. ”
To finish reading the complete interview with Matt Carlson on Wibotic click here.
WiBotic high power wireless charging systems are strong enough to charge a wide variety of robots, drones, and industrial automation equipment. The reliability of wireless charging gives robots and drones greater autonomy, requiring less human intervention and maintenance than contact-based charging systems.
“The FCC approval lets us meet customer demand by providing standard products to a rapidly growing industry,” said Waters. “As the industry continues to grow, robots and automation in general are facing more regulation and stricter safety and emissions requirements. We’re excited to help businesses solve some of these problems as they rapidly deploy larger autonomous fleets.”
WiBotic is the leader in wireless charging and fleet energy management solutions for the robotics industry and provides next generation off-the-shelf hardware and software systems that most customers can use out of the box. WiBotic wireless charging has greater range and is more reliable than contact-based systems. Robots and drones no longer need millimeter-level navigational accuracy to successfully dock for charging. With full power delivery within several centimeters of the transmitter, robots can connect to power with greater ease and reliability, improving overall uptime. WiBotic software enables a comprehensive visualization of all battery charging data across a fleet, and enables precision docking algorithms to be fast and reliable. By optimizing power across a fleet, system efficiencies can be increased and maintenance costs can be reduced substantially over time.
“FCC approval is a major achievement, representing thousands of hours of product development and testing,” said Waters. “The engineering of WiBotic designs to comply with FCC requirements was a non-trivial task. I am extremely proud of our team and grateful to have achieved this milestone alongside everyone at WiBotic.”
Researchers Develop Self-Healing Soft Robot Actuators
A team of researchers at Penn State University has developed a solution to the wear on soft robotic actuators due to repeated activity: a self-healing, biosynthetic polymer based on squid ring teeth. The material is beneficial to actuators, but it could also be applied anywhere that tiny holes could cause problems, such as hazmat suits.
According to the report in Nature Materials, “Current self-healing materials have shortcomings that limit their practical application, such as low healing strength and long healing times (hours).”
Drawing inspiration from self-healing creatures in nature, the researchers created high-strength synthetic proteins. They are able to self-heal minute and visible damage.
Melik Demirel is a professor of engineering science and mechanics and the holder of the Lloyd and Dorothy Foehr Huch Chair in Biomimetic Materials.
“Our goal is to create self-healing programmable materials with unprecedented control over their physical properties using synthetic biology,” he said.
Robotic Arms and Prosthetics
Some robotic machines, such as robotic arms and prosthetic legs, rely on joints that are constantly moving. This requires a soft material, and the same is true for ventilators and various types of personal protective equipment. These materials, and any that undergo continual repetitive motion, are at risk of developing small tears and cracks, eventually breaking. WIth the use of self-healing material, these tiny tears can be quickly repaired before any serious damage is done.
DNA Tandem Repeats
The team of researchers created the self-healing polymer by using a series of DNA tandem repeats consisting of amino acids produced by gene duplication. Tandem repeats are often a short series of molecules that can repeat themselves an unlimited number of times.
Abdon Pena-Francelsch is lead author of the paper and a former doctoral student in Demirel’s lab.
“We were able to reduce a typical 24-hour healing period to one second so our protein-based soft robots can now repair themselves immediately,” Abdon Pena-Francelsch said. “In nature, self-healing takes a long time. In this sense, our technology outsmarts nature.”
According to Demirel, the self-healing polymer can heal itself with the application of water, heat, and even light.
“If you cut this polymer in half, when it heals it gains back 100 percent of its strength,” Demirel said.
Metin Sitti is direcor of the Physical Intelligence Department at the Max Planck Instiute for Intelligent Systems, Stuttgart, Germany.
“Self-repairing physically intelligent soft materials are essential for building robust and fault-tolerant soft robots and actuators in the near future,” Sitti said.
The team was able to create the rapidly-healing soft polymer by adjusting the number of tandem repeats. It is able to retain its original strength, and at the same time, they were able to make the polymer 100% biodegradable and 100% recyclable into the same polymer.
“We want to minimize the use of petroleum-based polymers for many reasons,” Demirel said. “Sooner or later we will run out of petroleum and it is also polluting and causing global warming. We can’t compete with the really inexpensive plastics. The only way to compete is to supply something the petroleum based polymers can’t deliver and self-healing provides the performance needed.”
According to Demirel, many of the petroleum-based polymers are able to be recylced, but it has to be into something different.
The biomimetic polymers are able to biodegrade, and acids like vinegar are able to recycle it into a powder which can then be manufactured into the original self-healing polymer.
Stephanie McElhinny is a biochemistry program manager at the Army Research Office.
“This research illuminates the landscape of material properties that become accessible by going beyond proteins that exist in nature using synthetic biology approaches, McElhinny said. “The rapid and high-strength self-healing of these synthetic proteins demonstrates the potential of this approach to deliver novel materials for future Army applications, such as personal protective equipment or flexible robots that could maneuver in confined spaces.”
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