Robots have already become an indispensable part of our lives. However currently, most robots are relatively rigid machines which make unnatural movements. The emerging field of soft robotics aims to improve robot/human interactivity promising to bring robots into all aspects our daily lives, including wearable robotics, surgical robots, micromanipulation, search and rescue, and others.
Potential applications for these robots include patient rehabilitation, handling fragile objects, biomimetic systems and home care. Robots with greater flexibility could also help in military operations, where level terrain and unobstructed areas are rare, whether as a fully intact robot or as, say, a strap-on arm with a pneumatically controlled hand that could extend the reach, strength or capability of what a person could do.
Soft Robotics arms can come in handy when carrying these soldiers without causing injury. “We have lost medics throughout the years because they have the courage to go forward and rescue their comrades under fire. With the newer technology, with the robotic vehicles we are using even today to examine and to detonate IEDs [improvised explosive devices], those same vehicles can go forward and retrieve casualties,” Major General Steve Jones, commander of the Army Medical Department Center, said.
Evacuating casualties was only one of the roles for robots in battlefield medicine that Jones discussed. Another option is delivering medical supplies to dangerous areas, supporting troops operating behind enemy lines. To some extent we already have this, thanks to the Snowgoose powered glider, but future drones could do more, like deliver specific medicines or even blood. In the battlefields of tomorrow, when troops call for help, the cavalry that comes may be robots.
Soft robotics differ from traditional counterparts in some important ways: Soft robots have little or no hard internal structures. Instead they use a combination of muscularity and deformation to grasp things and move about. Rather than using motors, cables or gears, soft robots are often animated by pressurized air or liquids. In many cases soft robotics designs mimic natural, evolved biological forms hence also called bio-inspired robots. This, combined with their soft exteriors, can make soft robots more suitable for interaction with living things or even for use as human exoskeletons.
Soft and deformable structures are crucial in the systems that deal with uncertain and dynamic task-environments, e.g. grasping and manipulation of unknown objects, locomotion in rough terrains such as ocean floor, and physical contacts with living cells and human bodies. These robots must move over rough terrain without getting stuck and need manipulators that can grab whatever strangely shaped objects they encounter.
“There is a great need in the health care system for lightweight, lower-cost wearable exoskeleton designs to support stroke patients, individuals diagnosed with multiple sclerosis and senior citizens who require mechanical mobility assistance,” said Larry Jasinski, CEO of ReWalk. Currently in the United States, there are an estimated 3 million stroke patients and 400,000 MS patients who are suffering from limited mobility due to lower limb disabilities.
Soft robots can become aides for the disabled or the elderly if they can be trusted not to hurt the people they come into contact with. Miniature soft robots could even serve as surgical tools inside the body.
Many industries are searching for new ways to use robots, including developing machines that can work alongside humans and those that are more versatile than the single-task assembly line bots of years past. Company Soft Robotics has developed fingerlike grippers are made of flexible material, such as silicone, and powered by compressed air especially useful in warehouse and assembly line markets — particularly in the food industry, where robots aren’t typically trusted to handle delicate items like fresh produce.
“Despite its importance and considerable demands, the field of Soft Robotics faces a number of fundamental scientific challenges: the studies of unconventional materials are still in their exploration phase, and it has not been fully clarified what materials are available and useful for robotic applications; tools and methods for fabrication and assembly are not established; we do not have broadly agreed methods of modeling and simulation of soft continuum bodies; it is not fully understood how to achieve sensing, actuation and control in soft bodied robots; and we are still exploring what are the good ways to test, evaluate, and communicate the soft robotics technologies,” says IEEE Robotics and Automation Society.
Scientists are also studying how soft robots could lead to major breakthroughs in the development of self-repairing, growing and self-replicating robots, according to the IEEE Robotics and Automation Society. Borgatti explained how soft robots can react to their environments – a major factor for future government use. For example, soft robots can be designed to navigate difficult terrain like shifting sand and fall without being damaged – picking themselves up and correcting their course.
Scientists develop robot that can feel
Group of roboticists in the Department of Biomedical Engineering at the Georgia Institute of Technology in Atlanta, has developed a robot arm that moves and finds objects by touch. In a paper published in the International Journal of Robotics Research, the Georgia Tech group described a robot arm that was able to reach into a cluttered environment and use “touch,” along with computer vision, to complete exacting tasks.
Dr. Kemp said the researchers using digital simulations and a simple set of primitive robot behaviors were able to develop algorithms used gave the arm qualities that seemed to mimic human behavior. For example, the robot was able to bend, compress and slide objects. Also, given parameters designed to limit how hard it could press on an object, the arm was able to pivot around objects automatically.
The arm was designed to essentially have “springs” at its joints, making it “compliant,” a term roboticists use to define components that are more flexible and less precise than conventional robotic mechanisms. Compliance has become increasingly important as a new generation of safer robots has emerged.The robot also has an fabric based artificial “skin” equipped with force sensors and thermal sensors that can sense pressure or touch enabling the home care robot to lightly touch different materials and identify it.
According to Georgia Tech, Director of the Healthcare Robotics Lab at Georgia Tech Charles C. Kemp
said that, “These environments tend to have clutter. In a home, you can have lots of objects on a shelf,
and the robot can’t see beyond that first row of objects.” The combination of the sensors can help the home care robot to know the difference between wood and metal. The experts from IEEE Spectrum indicate that the technique copies the way how the human skin uses thermal conductivity to classify different materials.
Robot Octopus Points the Way to Soft Robotics with Eight Wiggly Arms
Cecilia Laschi, professor at the BioRobotics Institute at the Scuola Superiore Sant’Anna, in Pisa, Italy, and her team are investigating soft robots that mimic the form of the octopus. “The octopus has neither an internal nor external skeleton, and its eight arms can bend at any point, elongate and shorten, and stiffen to apply force. It can twist its arms around objects and manipulate them with great dexterity,” she writes. Team has already built robot octopus that could crawl along the seafloor mimicking locomotion of octopus.
The team is creating artificial muscles using materials called shape-memory alloys (SMAs). “When heated, SMAs deform to a predefined shape, which they “remember.” We fashioned SMA wires into springs and ran electric current through them to heat them, causing the springs to scrunch up in a way that imitates muscular contractions.”
“For the Octopus project, my team constructed a prototype arm using SMA springs to stand in for the longitudinal and transverse muscles found in the limbs of a real octopus. By sending current through different sets of springs, we made the underwater arm bend at multiple points, shorten and elongate, even grasp things,” she explains.
“Our work is primarily meant to demonstrate the potential of soft robotics, and much work remains before a robot octopus will be ready to crawl out of the lab.”
Harvard researchers have created the first soft octopus robot that is completely self-contained. It is basically a pneumatic tube has no hard electronic components—no batteries or computer chips—and moves without being tethered to a computer.
The octobot is powered by hydrogen peroxide is pumped into two reservoirs inside the middle of the octobot’s body. Pressure pushes the liquid through tubes inside the body, where it eventually hits a line of platinum, catalyzing a reaction that produces a gas. From there, the gas expands and moves through a tiny chip known as a microfluidic controller.
It alternately directs the gas down one half of the octobot’s tentacles at a time which enables octopus to wiggle its tentacles. The octobot can move for about eight minutes on one milliliter of fuel.
“You have to make all the parts yourself,” says Ryan Truby, a graduate student in Jennifer Lewis’s lab at Harvard, where the materials half of this research is taking place. The mold for the octopus shape and the microfluidic chip were among the things developed nearby in Robert Woods’s lab.
Harvard Engineers Create a 3D Printed Autonomous Robot
SEAS researchers have built one of the first 3-D printed, soft robot that moves autonomously. The design offers a new solution to an engineering challenge that has plagued soft robotics for years: the integration of rigid and soft materials.
The robot is constructed of two main parts: a soft plunger like body with three pneumatic legs and the rigid core module, containing power and control components and protected by a semisoft shield created with a 3-D printer. This integration of the rigid components with the body of the soft robot through a gradient of material properties eliminates an abrupt, hard-to-soft transition that is often a failure point.
This design combines the autonomy and speed of a rigid robot with the adaptability and resiliency of a soft robot and, because of 3-D printing, is relatively cheap and fast
The robot is combustion-powered, to initiate movement, the robot inflates its pneumatic legs to tilt its body in the direction it wants to go. Then butane and oxygen are mixed and ignited, catapulting the robot into the air. It’s a powerful jumper, reaching up to six times its body height in vertical leaps and half its body width in lateral jumps. In the field, the hopping motion could be an effective way to move quickly and easily around obstacles.
“The wonderful thing about soft robots is that they lend themselves nicely to abuse,” said Nicholas Bartlett, first author of the paper and a graduate student at SEAS. “The robot’s stiffness gradient allows it to withstand the impact of dozens of landings and to survive the combustion event required for jumping. Consequently, the robot not only shows improved overall robustness but can locomote much more quickly than traditional soft robots.”
The robot’s jumping ability and soft body would come in handy in harsh and unpredictable environments or disaster situations, allowing it to survive large falls and other unexpected developments.
3D-Printed ‘Bionic Skin’ Could Give Robots the Sense of Touch
Engineering researchers at the University of Minnesota have developed a revolutionary process for 3D printing stretchable electronic sensory devices that could give robots the ability to feel their environment. The discovery is also a major step forward in printing electronics on real human skin.
This ultimate wearable technology could eventually be used for health monitoring or by soldiers in the field to detect dangerous chemicals or explosives.“While we haven’t printed on human skin yet, we were able to print on the curved surface of a model hand using our technique,” McAlpine said. “We also interfaced a printed device with the skin and were surprised that the device was so sensitive that it could detect your pulse in real time.”
McAlpine and his team made the unique sensing fabric with a one-of-a kind 3D printer they built in the lab. The multifunctional printer has four nozzles to print the various specialized “inks” that make up the layers of the device—a base layer of silicone, top and bottom electrodes made of a conducting ink, a coil-shaped pressure sensor, and a sacrificial layer is later washed away in the manufacturing process.
“This is a completely new way to approach 3D printing of electronics,” McAlpine said. “We have a multifunctional printer that can print several layers to make these flexible sensory devices. This could take us to so many directions from health monitoring to energy harvesting to chemical sensing.
Soft Robotic Fingers Recognize Objects by Feel
Rus and her team at Distributed Robotics Lab at CSAIL have created bendable and stretchable robotic fingers made out of silicone rubber that can lift and handle objects as thin as a piece of paper and as delicate as an egg.
Rus incorporated “bend sensors” into the silicone fingers so that they can send back information on the location and curvature of the object being grasped. Then, the robot can pick up an unfamiliar object and use the data to compare to already existing clusters of data points from past objects.
“By embedding flexible bend sensors into each finger, we got an idea of how much the finger bends, and we can close the loop from how much pressure we apply,” says Katzschmann. “In our case, we were using a piston based closed pneumatic system.”
Currently, the robot can acquire three data points from a single grasp, meaning the robot’s algorithms can distinguish between objects which are very similar in size. The researchers hope that further advances in sensors will someday enable the system to distinguish between dozens of diverse objects.
Carnegie Mellon researchers
Carnegie Mellon researchers are working to make a robot’s movements more human-like, incorporating technologies such as artificial muscles, touch sensors, stretchable films, flexible electronics and pressure-sensitive skins.
DARPA supports Carnegie Mellon’s research—as well as research by iRobot and Otherlab—through its Maximum Mobility Manipulation, or M3, program. M3’s research into soft robotics aims to increase the mobility of robots while creating a framework for fast prototyping and production, including fabricating robotics with 3D printing.
The U.S. Army and Special Forces community is particularly invested in soft robotics and what it could mean for the Iron Man exoskeleton it wants to build under the Tactical Assault Light Operator Suit program. The Department of Veterans Affairs is also seeking research into soft robotics for exoskeletons to aid wounded veteran.
Wyss Institute developing wearable exosuits
Army researchers have evaluated prototype devices developed for the Defense Advanced Research Projects Agency at Maryland’s Aberdeen Proving Ground. The prototype was developed by researchers from Harvard University’s Wyss Institute under DARPA Warrior Web program.
The lightweight Soft Exosuit is designed to overcome the challenges of traditional heavier exoskeleton systems, such as power-hungry battery packs and rigid components that can interfere with natural joint movement. The exosuit is made of soft, functional textiles interwoven into a piece of smart clothing that is pulled on like a pair of pants. It mimics the actions of leg muscles and tendons when a user walks and provides periodic assistance at the joints.
It is intended to be worn comfortably under clothing and could enable soldiers to walk longer distances, keep fatigue at bay, and minimize the risk of injury when carrying heavy loads. Alternative versions of the suit could eventually assist those with limited mobility as well
Instead of shielding the wearer, its purpose is to propel them forward and conserve their energy, explains Conor Walsh, lead researcher from Harvard’s Wyss Institute for Biologically Inspired Engineering. “We are intrigued by this challenge because we are so inspired by how our muscles and nervous systems work,” Walsh explains. Using a system of battery-powered sensors, motors, gears, cables and pulleys sandwiched between the fabric layers, the suit senses the wearer’s motion and responds to assist. So far, tests have shown energy savings of seven per cent, and in 2017 Walsh will share the final prototype “with more efficient actuators, sensors and cables,” he says
A series of webbing straps contain a microprocessor and a network of strain sensors— continuously monitoring various data signals, including the suit tension, the position of the wearer (e.g., walking, running, crouched), and more. Batteries and motors are mounted at the waist and cables transmit forces to the joints.
“The suit mimics the action of leg muscles and tendons so a Soldier’s muscles expend less energy,” said Dr. Ignacio Galiana, a robotics engineer working on the project. Galiana said the team looked to nature for inspiration in developing cables and pulleys that interact with small motors to provide carefully timed assistance without restricting movement.
Inspired by a deep understanding of the biomechanics of human walking, the Soft Exosuit technology is spawning the development of entirely new forms of functional textiles, flexible power systems, soft sensors, and control strategies that enable intuitive and seamless human-machine interaction.
DARPA had awarded the Wyss Institute for Biologically Inspired Engineering at Harvard University a $2.9 million contract to further develop the Soft Exosuit under Warrior Web program, which seeks to develop technologies to mitigate musculoskeletal injuries among military Service members while improving performance.
Super-Releaser is developing an orthotic exoskeleton called the Neucuff
Super-Releaser is developing an orthotic exoskeleton called the Neucuff that could drastically reduce the cost of orthotics. The Neucuff is an entirely soft robotic elbow orthosis that can fit a wide variety of bodies without any customization. It is aimed at allowing people with cerebral palsy to move their arms with enough strength and fidelity to take control of tasks like self feeding and dressing that might otherwise require live-in care.
“Soft robotics offers an avenue to apply force evenly across the body with an exoskeleton that is as gentle as it is strong. Being conformal by nature means a single design can fit a wide range of people just like any athletic brace,” according to Super-Releaser’s website.
These orthotics could mean considerable savings for wounded warriors returning from combat after a disabling injury. It could also help make exoskeletons more comfortable to wear, especially when bearing a heavy load.
Bomb Disposal Robot from Johns Hopkins Researchers
Researchers at Johns Hopkins’ Applied Physics Laboratory have added a pair of sophisticated prosthetic arms to a new bomb disposal robot, the Bimanual Dexterous Robotics Platform, more commonly known as Robo-Sally. The arms are based on the Modular Prosthetic Limb that the APL developed for DARPA as part of their Revolutionizing Prosthetics Program.
The robot is fitted with two mounted video cameras that give her forty-two degrees of freedom throughout her neck, torso, and base. To activate the arm, an operator wearing a special sensor-laden glove manipulates his arms and hands, and Sally mimics these movements. The sensors in the glove are so precise that Sally can actuate individual joints in her hands and fingers to exactly mimic what’s happening on the operator’s end
Robo-Sally has proven her ability to man a checkpoint, check a driver’s ID, and uncover and transport an IED in the field tests.
DARPA’s Warrior Web
The amount of equipment and gear carried by today’s dismounted warfighter can exceed 100 pounds, as troops conduct patrols for extended periods over rugged and hilly terrain. The added weight while bending, running, squatting, jumping and crawling in a tactical environment increases the risk of musculoskeletal injury, particularly on vulnerable areas such as ankles, knees and lumbar spine.
Increased load weight also causes increase in physical fatigue, which further decreases the body’s ability to perform warfighter tasks and protect against both acute and chronic injury.
The Warrior Web program seeks to develop the technologies required to prevent and reduce musculoskeletal injuries caused by dynamic events typically found in the warfighter’s environment. The ultimate program goal is a lightweight, conformal under-suit that is transparent to the user (like a diver’s wetsuit).
The suit seeks to employ a system (or web) of closed-loop controlled actuation, transmission, and functional structures that protect injury prone areas, focusing on the soft tissues that connect and interface with the skeletal system. Other novel technologies that prevent, reduce, ambulate, and assist with healing of acute and chronic musculoskeletal injuries are also being sought
DARPA’s Maximum Mobility and Manipulation (M3)
Robots hold great promise for amplifying human effectiveness in Defense operations. Compared to human beings and animals, however, the mobility and manipulation capability of present day robots is poor. In addition, design and manufacturing of current robotic systems are time consuming, and fabrication costs remain high. If these limitations were overcome, robots could assist in the execution of military operations far more effectively across a far greater range of missions.
The Maximum Mobility and Manipulation (M3) program is striving to create and demonstrate significant scientific and engineering advances in robotics that will:
- Create a significantly improved scientific framework for the rapid design and fabrication of robot systems and greatly enhance robot mobility and manipulation in natural environments.
- Significantly improve robot capabilities through fundamentally new approaches to the engineering of better design tools, fabrication methods, and control algorithms. The M3 program covers scientific advancement across four tracks: design tools, fabrication methodologies, control methods, and technology demonstration prototypes.
Due to the soft materials used, these robots can not only squeeze into tight spaces, but also recover more easily from collisions and pick up and handle irregularly-shaped objects. However, because of soft robots’ flexibility, they often struggle with correctly measuring where an object is, or whether they actually picked the object up.
Characterizing and predicting the behavior of soft multi-material actuators is challenging due to the nonlinear nature of both the hyper-elastic material and the large bending motions they produce. Key challenges in the design and manufacture of soft robots include the complex fabrication processes and the interfacing of soft and rigid components.
Fully soft sensors that can be incorporated into the actuator design during the manufacturing process are needed to control soft actuators; they provide means of monitoring their kinematics, interaction forces with objects in the environment and internal pressure.
The university research is focused on developing new materials like dielectric elastomers, carbon nanotube yarn and self-healing materials and on designing the controllers and actuators that animate them. New actuator technologies and fabrication approaches will bring about better force-speed operating points, variable impedance, more convenient form factors, and actuators without transmission mechanisms.
Polymer Embedded With Metallic Nanoparticles Enables Soft Robotics
Researchers at North Carolina State University (NCSU), in Raleigh, have developed a technique through movement can be induced into polymer through application of magnetic field by embedding nanoparticles of magnetite—an iron oxide—into a polymer.
“Using this technique, we can create large nanocomposites, in many different shapes, which can be manipulated remotely,” said Sumeet Mishra, lead author of the paper, in a press release. “The nanoparticle chains give us an enhanced response, and by controlling the strength and direction of the magnetic field, you can control the extent and direction of the movements of soft robots.”
In research described in a paper published in the journal Nanoscale, the NCSU researchers describe a process that starts with dispersing the nanoparticles in a solvent. Next, a polymer is dissolved into the mixture and the resulting fluid is poured into a mold. Then a magnetic field is applied that arranges the magnetite nanoparticles into parallel chains. Once the solution dries in the mold, the chains of nanoparticles are locked into place.
“The key here is that the nanoparticles in the chains and their magnetic dipoles are arranged head-to-tail, with the positive end of one magnetic nanoparticle lined up with the negative end of the next, all the way down the line,” said Joe Tracy, an associate professor at NCSU and corresponding author of the paper, in the press release. “When a magnetic field is applied in any direction, the chain re-orients itself to become as parallel as possible to the magnetic field, limited only by the constraints of gravity and the elasticity of the polymer.”
Soft Elastomeric Technology for explosive ordnance disposal
US Navy had released a SBIR, to develop and demonstrate technologies to fabricate cost-effective rapidly deployable lightweight actuated inflatable single or dual arm manipulation systems for integration onto underwater unmanned platforms.
Nature provides many examples of animals that have developed superior strategies for manipulation of their surroundings through the use of soft, robust and fast mechanisms.
These abilities have proven difficult to emulate with traditional engineering approaches, but new developments in inflatable technology using pressurized membranes made of compliant (elastomeric) materials create new opportunities for affordable manipulation systems for a range of naval underwater missions. Such manipulation systems would avoid costly motors by replacing them with pump driven fluid-filled fabric membranes.
These materials can be used in the fabrication of lightweight actuated inflatable manipulation systems which are resilient to impact, can be compactly stowed and are safe to operate near humans. The technical challenges include the design of integrated actuation and fabric, distributed actuation to mimic effective bio-inspired energy efficiency, and dexterity to perform an array of underwater tasks.
The manipulation system should be able to perform elementary tasks such as precise positioning of objects or tools, removal or emplacement of objects (lifting at least 25 pounds), and pull or twist manipulations (eg. unscrewing a cap from a pipe), which are common tasks performed in explosive ordnance disposal.
Ideally, these arms would be capable of operating on land or underwater, to depths of 200 feet.
EPFL’s Reconfigurable Robotics Lab (RRL)
Soft robots, powered by muscle-like actuators, are designed to be used on the human body in order to help people move. They are made of elastomers, including silicon and rubber, and so they are inherently safe. They are controlled by changing the air pressure in specially designed ‘soft balloons’, which also serve as the robot’s body. EPFL’s Reconfigurable Robotics Lab (RRL) has developed a predictive model that can be used to carefully control the mechanical behavior of the robots’ various modules has been published in Scientific Reports.
We conducted numerous simulations and developed a model for predicting how the actuators deform as a function of their shape, thickness and the materials they’re made of,” said Gunjan Agarwal, the article’s lead author. “Elastomer structures are highly resilient but difficult to control. We need to be able to predict how, and in which direction, they deform. And because these soft robots are easy to produce but difficult to model, our step-by-step design tools are now available online for roboticists and students.”
A rehabilitation belt
In addition to these simulations, other RRL researchers have developed soft robots for medical purposes. This work is described in Soft Robotics. One of their designs is a belt made of several inflatable components, which holds patients upright during rehabilitation exercises and guides their movements.
“We are working with physical therapists from the University Hospital of Lausanne (CHUV) who are treating stroke victims,” said Matthew Robertson, the researcher in charge of the project. “The belt is designed to support the patient’s torso and restore some of the person’s motor sensitivity.”
The belt’s soft actuators are made of pink rubber and transparent fishing line. The placement of the fishing line guides the modules’ deformation very precisely when air is injected. “For now, the belt is hooked up to a system of external pumps. The next step will be to miniaturize this system and put it directly on the belt,” said Robertson.
Adaptable and reconfigurable robots
Potential applications for soft actuators don’t stop there. The researchers are also using them to develop adaptable robots that are capable of navigating around in cramped, hostile environments. And because they are completely soft, they should also be able to withstand squeezing and crushing.
“Using soft actuators, we can come up with robots of various shapes that can move around in diverse environments,” said Paik. “They are made of inexpensive materials, and so they could easily be produced on a large scale. This will open new doors in the field of robotics.”
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