The automation of a production line has become a major issue for many industries, and the need to increase productivity while having a good return on investment has caused many concerns. The main area in which these challenges are tackled is bin-picking.Moving a part from a container to place it to a specific position, ready for the next step, sounds very simple, but it becomes complex when you need to abide to cycle-time requirements.As demand for accurate, autonomous and flexible bin-picking systems increase, Visio Nerf has produced a handbook to the technology designed introduce key concepts and offer concrete examples of cutting-edge technology. Below are some of thehighlights from the handbook. The book guide can be downloaded <a href="https://content.visionerf.com/from-2d-to-3d-the-operating-principles-of-industrial-vision-systems-0?hsCtaTracking=59e2a72a-d663-450a-af5e-51d259af5ed1%7C0aa52600-51c0-4eb1-a0a5-d30cb78dc3a7" rel="noopener noreferrer" target="_blank">here.&nbsp;</a><h2>Introduction to Bin-Picking</h2>The automation of production cells is at the heart of current concerns for many industries, the main objective being to find the right balance between investment and improved productivity. One of the operations for which the evolution towards a high-performance automated production tool has become necessary is Bin-Picking.&nbsp;Bin-picking involves moving a part from its original position to a specific delivery zone to make it available for the next production step. The workpiece is initially placed in a container or on a conveyor in a random, semi or fully-ordered manner depending on the application. The main challenge of Bin-Picking is to offer an efficient automated solution to meet cycle time optimization requirements, to protect operators from difficult and repetitive tasks particularly in harsh environments while increasing the flexibility and productivity of the work cell. Technological advances in the field of machine vision and calculation software can now provide solutions adapted to most industrial applications.<h2>Essential criteria for assessing bin-picking</h2>In order to assess the efficiency of a Bin-Picking cell and determine its dimensioning, several criteria must be taken into account:&nbsp;<ul><li>Cell cycle time&nbsp;</li><li>Bin emptying rate&nbsp;</li><li>Part pick and place accuracy</li></ul>These elements aim to measure and improve, more or less directly, the profitability of the cell at different times of its cycle life. A fourth factor to consider, that is too often overlooked, is the flexibility of the cell or its ability to be reused in several applications.With Industry 4.0, companies are looking for agile cells that can be reused without too many modifications when the type of the parts to be picked changes. These four criteria are intrinsically linked. For example, a suboptimal emptying rate may require the addition of mechanical systems to shake the bin or a change to more appropriate tools to complete the task. Integration of such elements extends the cycle time and penalizes the flexibility of the cell. Appropriate bin-picking cell sizing is essential and involves finding the right balance between these criteria. &nbsp;To read more about the technology behind bin-picking, download the full guide, written by Adib Rebbouh with Visio-Nerf&nbsp;<a href="https://content.visionerf.com/from-2d-to-3d-the-operating-principles-of-industrial-vision-systems-0?hsCtaTracking=59e2a72a-d663-450a-af5e-51d259af5ed1%7C0aa52600-51c0-4eb1-a0a5-d30cb78dc3a7" rel="noopener noreferrer" target="_blank">here</a>.&nbsp;

This handbook introduces the concept of bin-picking, and explores its complexity through real-case studies.

The Bin-Picking Handbook For Engineers

<h2 id="isPasted">Introduction</h2><a href="http://www.preziosa.com/inglese/index.php" target="_blank">Preziosa Francesco SRL</a> is a manufacturer of sheet metal cabinets based in Bergamo, Italy. They have been leading the Italian market for the past 40 years. Marco Preziosa, the company’s CEO, takes pride in the quality of the products that come out of their factory. He also values his company’s flexibility to customize their standard line to their customers’ specific needs.The engineers of Preziosa Francesco SRL are always on the lookout for the latest technologies that can improve its processes and workflows and enable them to stay competitive. Today, in the core of their activities lies a robotic cell and an automated press brake bending machine. Yet, this investment worth hundreds of thousand euros is at stake because of a relatively cheap part: the robotic end effector’s gripper.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1635924635705-ezgif-6-31fa52feb378.gif" style="width: 766px;" class="fr-fic fr-dib"> Robotic grippers are custom components that often need to be changed to meet the requirements of a custom sheet metal job. Preziosa Francesco SRL partnered with <a href="http://www.add-it.tech/" target="_blank">Additive Italia</a> (Add-it, for short) to redesign their robot grippers for metal Additive Manufacturing. Add-it is a design consultancy specializing in simulation-driven engineering and generative design.&nbsp;In this case study, we document how Preziosa Francesco and Add-it used the advanced engineering capabilities of nTopology to create a reusable design workflow for robotic grippers. This way, they improved the system’s performance and bypassed a supply chain challenge.<h2>Practical Robot Gripper Design Challenges</h2>Preziosa Francesco uses a Fanuc M710-iC robotic arm to load metal sheets onto their automatic press brake bending machine, orient and maintain their position during the bending operations, and then store the parts in the appropriate baskets.<div class="fr-img-space-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1635924683111-add-it-cs-image-03-scaled.jpg" style="width: 766px;" class="fr-fic fr-dib">Factory setup of the automatic press brake bending machine&nbsp;</div>The system is equipped with two metal grippers to handle the part during bedding operations. The production team at Preziosa Francesco was facing three main technical challenges related to this simple component. These challenges directly influenced the quality of their products and the productivity of their system:<ul><li>The standard flat grippers were too slippery. Due to inefficient traction between the sheet metal and the original CNC machined gripper, sheet metal moving during bending, reducing the accuracy of the end product.</li><li>The standard grippers were not agile enough. Due to their size, the sides of the gripper were in danger of colliding with the machine at certain bending angles, causing the system to stop.</li><li>Manufacturing custom grippers was too slow.&nbsp;Ideally, a different gripper should be used for different sheet thickness and blank size. Outsourcing the job to a CNC machine shop would take at least two weeks, which is unacceptable.</li></ul><h2>End-to-end Design &amp; Digital Manufacturing Workflow</h2>To overcome these challenges, the engineers of Add-it re-designed the gripper for Additive Manufacturing. They selected metal 3D printing in 17-4 PH stainless steel with Desktop Metal’s Studio System as the manufacturing process due to its ability to quickly produce metal parts in-house.&nbsp;<div class="fr-img-space-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1635924709859-add-it-cs-image-04-v2-scaled.jpg" style="width: 766px;" class="fr-fic fr-dib">A breakdown of the redesign process — from concept to application in less than 4 days&nbsp;</div>The team also considered polymer 3D printing as an option but quickly moved away from this solution. For heavy-duty industrial applications, a polymer gripper would wear quickly, loosening the clamping efficiency and reducing the accuracy of the process over time. In this application, repeatability was essential.A primary goal for this project was to create a process that could be easily replicated. A reusable design process would allow the team to modify the gripper quickly and adjust it to the specific needs of each manufacturing job. This way, the team could create an end-to-end digital manufacturing workflow.&nbsp;nTopology was a natural choice for the engineering team. “We immediately decided to start this project with nTopology due to the variety of grips that we could make,” mentioned Gianluigi Rossi, the lead design engineer of this project.<h2>Increasing Grip Force using Lattice Structures</h2>Friction is often not enough to ensure a good grip, especially when precise positioning under high loading conditions is required. A common way to increase grip — and hence the reliability of the bending process — is to add a traction pattern to the robot gripper. The grooves of a traction pattern cause the softer material to deform (in this case, the aluminum sheet), mechanically interlocking the parts together and increasing grip.The engineers of Add-it experimented with two initial design variations. First, they consolidated the assembly of the gripper and the stop reference into a single component. Then, they applied two different patterns to the gripper: grooves created using a surface lattice and honeycomb-like perforation pattern. The goal of this conservative DfAM redesign was to test the accuracy of the metal 3D printing process.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1635924737550-add-it-cs-image-05-scaled.jpg" style="width: 766px;" class="fr-fic fr-dib">They found through testing that the honeycomb-like perforation pattern provided better traction and was easier to manufacture using metal 3D printing. This design was used as a basis for the later iterations.What stood out to the team during this project was the speed of iterations. They moved from concept to application in less than 4 days.&nbsp;This rapid momentum was enabled to a large extent by the design capabilities of nTopology.<blockquote>“Shifting from classic CAD software to nTopology is a radical leap. I interfaced with another way of working and thinking. This software can open new paths, such as reusing the same workflow for other geometries and sharing it with colleagues. This is a unique time-saving in the working environment. In one afternoon, we managed to make the component we needed. In a few minutes, we could change the type of grip and produce a part that was ready to manufacture.” <cite>Gianluigi Rossi, Design Engineer, Add-it</cite></blockquote><h2>Topology Optimization to Design More Agile Robots</h2>The closer the gripper can reach the press brake, the safer and more repeatable the process can get. However, even small variations in sheet thickness can cause the gripper to collide with the machine tool at certain angles, resulting in stops. Replacing the standard gripper with a more slender design expands the robot’s safe zone and increases its agility.&nbsp;This was the objective of the second design iteration. The engineers of Add-it used nTopology’s built-in topology optimization capabilities to generate a gripper with optimized geometry. The primary goal was not to reduce the part’s weight but to create a design with similar performance — stiffness, grip force, weight — but a smaller footprint.&nbsp;The topology optimized gripper enabled the system to perform more delicate robotic operations and handle smaller metal sheets. “We estimated the space that we needed to save in the volume of the clamps. It was a matter of a few millimeters. Still, it was a few millimeters that counted in this application,” Rossi notes.<div class="fr-img-space-wrap"><img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1635924763041-add-it-cs-image-06-scaled.jpg" style="width: 766px;" class="fr-fic fr-dib">Overview of the fully automated post-topology optimization design workflow in nTopology&nbsp;&nbsp;</div>The team designed and 3D printed two variations of the topology optimized gripper using two different levels for the density threshold. Using nTopology, Rossi automatically reconstructed and smoothened the topology optimization results, bypassing a time-consuming manual step that is common in other software. Since the team didn’t have to recreate the part geometry manually, multiple variations could be generated with only a few clicks.&nbsp;In fact, when Add-it first started using nTopology, they used to <a href="https://ntopology.com/videos/video/ntop-live-automated-reconstruction-of-topology-optimization-from-altair-optistruct-in-ntopology/" target="_blank">import results of third part topology optimization tools</a> in nTopology — like Altair Optistruct® — just to take advantage of the software’s automated reconstruction capabilities. Now, the Add-it team is using nTopology for all their topology optimization needs due to its streamlined workflows and greater level control.<h2>Ensuring Process Reliability with Reusable Design Processes</h2>Every unforeseen change in the design has an impact on the quality of the end product. In the case of the gripper, even a few millimeters can make your process reliable or unreliable. The more flexible you are at adapting your tools to an ever-changing environment, the better the chances to succeed as a business.For Preziosa Francesco, the redesigned gripper greatly improved process reliability. By eliminating stops, it unlocked lights-out manufacturing and the full utilization of their robotic manufacturing system.Additionally, the ability to produce the parts they needed in-house in a few days enables Preziosa Francesco to adapt their system on short notice. They can also revisit their processes when necessary. The reusable design workflows created in nTopology were the missing link for taking full advantage of its Desktop Metal Studio System’s manufacturing capabilities.<blockquote>“If you don’t have a very repeatable process, you are forced to run production only during the day. It is very economically difficult to have these machines operate during day-shift only. Theoretically, you can have a very clever production system. But if it doesn’t work as intended because of a cheap part, an investment worth hundreds of thousands is at stake. nTopology allowed us to use robotic manufacturing our Desktop Metal Studio System to its full potential.” <cite>Marco Preziosa, CEO, Preziosa Francesco SRL</cite></blockquote><h2>The Next Steps</h2>With the new grippers proving their value in action, Preziosca Francesco SLR and Add-it are now looking to replicate this process of other applications. For example, they are designing clamp replacements and spare parts for the company’s punching machine.&nbsp;As for improvements on the existing workflow, the engineers of Add-it are now investigating how to create a new topology optimized version of the gripper that is twice as long while remaining durable and reliable. This way, they would generate a customizable clamping tool that is even more maneuverable and flexible.<hr>This article was first published on the&nbsp;<a href="https://ntopology.com/case-studies/robot-gripper-topology-optimization-metal-3d-printing/" id="isPasted" rel="noopener noreferrer" target="_blank">nTopology blog</a>.

Close-up of the robot with the redesigned gripper in action

Preziosa Francesco SRL & Add-it redesigned the grippers of their in-house press brake bending robotic cell for metal 3D printing. The final design was ready for application in just 4 days, increased system reliability, bypassed a supply chain bottleneck, and enabled lights-out manufacturing.

Agile Industrial Robot Grippers with Topology Optimization & Metal 3D Printing

Right now, about 500,000 pieces of human-made debris are whizzing around space, orbiting our planet at speeds up to 17,500 miles per hour. This debris poses a threat to satellites, space vehicles and astronauts aboard those vehicles.What makes tidying up especially challenging is that the debris exists in space. Suction cups don&rsquo;t work in a vacuum. Traditional sticky substances, like tape, are largely useless because the chemicals they rely on can&rsquo;t withstand the extreme temperature swings. Magnets only work on objects that are magnetic. Most proposed solutions, including debris harpoons, either require or cause forceful interaction with the debris, which could push those objects in unintended, unpredictable directions.To tackle the mess, researchers from Stanford University and NASA&rsquo;s Jet Propulsion Laboratory (JPL) have designed a new kind of robotic gripper to grab and dispose of the debris, featured in the June 27 issue of Science Robotics.<blockquote>&ldquo;What we&rsquo;ve developed is a gripper that uses gecko-inspired adhesives,&rdquo; said <a href="https://profiles.stanford.edu/mark-cutkosky" target="_blank">Mark Cutkosky</a>, professor of mechanical engineering and senior author of the paper. &ldquo;It&rsquo;s an outgrowth of work we started about 10 years ago on climbing robots that used adhesives inspired by how geckos stick to walls.&rdquo;</blockquote>The group tested their gripper, and smaller versions, in their lab and in multiple zero-gravity experimental spaces, including the International Space Station. Promising results from those early tests have led the researchers to wonder how their grippers would fare outside the station, a likely next step.<iframe src="https://www.youtube.com/embed/6hHv4li2JbY?&wmode=opaque" frameborder="0" allowfullscreen="" class="fr-draggable" style="width: 1114px; height: 645px;"></iframe>&ldquo;There are many missions that would benefit from this, like rendezvous and docking and orbital debris mitigation,&rdquo; said Aaron Parness, MS &rsquo;06, PhD &rsquo;10, group leader of the Extreme Environment Robotics Group at JPL. &ldquo;We could also eventually develop a climbing robot assistant that could crawl around on the spacecraft, doing repairs, filming and checking for defects.&rdquo;<h2>Creating a gecko gripper</h2>The adhesives developed by the&nbsp;<a href="http://bdml.stanford.edu/" target="_blank">Cutkosky lab</a> have previously been used in climbing robots and even a system that allowed humans to&nbsp;<a href="http://news.stanford.edu/news/2014/november/gecko-inspired-device-112114.html" target="_blank">climb up certain surfaces</a>. They were inspired by geckos, which can climb walls because their feet have microscopic flaps that, when in full contact with a surface, create a Van der Waals force between the feet and the surface. These are weak intermolecular forces that result from subtle differences in the positions of electrons on the outsides of molecules.The gripper is not as intricate as a gecko&rsquo;s foot &ndash; the flaps of the adhesive are about 40 micrometers across while a gecko&rsquo;s are 200 about nanometers &ndash; but the gecko-inspired adhesive works in much the same way. Like a gecko&rsquo;s foot, it is only sticky if the flaps are pushed in a specific direction but making it stick only requires a light push in the right direction. This is a helpful feature for the kinds of tasks a space gripper would perform.&ldquo;If I came in and tried to push a pressure-sensitive adhesive onto a floating object, it would drift away,&rdquo; said Elliot Hawkes, MS &lsquo;11, PhD &lsquo;15, a visiting assistant professor from the University of California, Santa Barbara and co-author of the paper. &ldquo;Instead, I can touch the adhesive pads very gently to a floating object, squeeze the pads toward each other so that they&rsquo;re locked and then I&rsquo;m able to move the object around.&rdquo;The pads unlock with the same gentle movement, creating very little force against the object.The gripper the researchers created has a grid of adhesive squares on the front and arms with thin adhesive strips that can fold out and move toward the middle of the robot from either side, as though it&rsquo;s offering a hug. The grid can stick to flat objects, like a solar panel, and the arms can grab curved objects, like a rocket body.One of the biggest challenges of the work was to make sure the load on the adhesives was evenly distributed, which the researchers achieved by connecting the small squares through a pulley system that also serves to lock and unlock the pads. Without this system, uneven stress would cause the squares to unstick one by one, until the entire gripper let go. This load-sharing system also allows the gripper to work on surfaces with defects that prevent some of the squares from sticking.The group also designed the gripper to switch between a relaxed and rigid state.&ldquo;Imagining that you are trying to grasp a floating object, you want to conform to that object while being as flexible as possible, so that you don&rsquo;t push that object away,&rdquo; explained Hao Jiang, a graduate student in the Cutkosky lab and lead author of the paper. &ldquo;After grasping, you want your manipulation to be very stiff, very precise, so that you don&rsquo;t feel delays or slack between your arm and your object.&rdquo;<h2>Gecko-inspired adhesive in zero-G</h2>The group first tested the gripper in the Cutkosky lab. They closely measuredhow much load the gripper could handle, what happened when different forces and torques were applied and how many times it could be stuck and unstuck. Through their partnership with JPL, the researchers also tested the gripper in zero-gravity environments.In JPL&rsquo;s Robodome, they attached small rectangular arms with the adhesive to a large robot, then placed that modified robot on a floor thatresembled a giant air-hockey table to simulate a 2D zero-gravity environment. They then tried to get their robot to scoot around the frictionless floor and capture and move a similar robot.&ldquo;We had one robot chase the other, catch it and then pull it back toward where we wanted it to go,&rdquo; said Hawkes. &ldquo;I think that was definitely an eye-opener, to see how a relatively small patch of our adhesive could pull around a 300 kilogram robot.&rdquo;Next, Jiang and Parness went on a parabolic airplane flight to test the gripper in zero gravity. Over two days, they flew a series of 80 ascents and dives, which created an alternating experience of about 20 seconds of 2G and 20 seconds of zero-G conditions in the cabin. The gripper successfully grasped and let go of a cube and a large beach ball with a gentle enough touch that the objects barely moved when released.Lastly, Parness&rsquo;s lab developed a small gripper that went up in the International Space Station (ISS), where they tested how well the grippers worked inside the station.Next steps for the gripper involve readying it for testing outside the space station, including creating a version made of longer lasting materials able to hold up to high levels of radiation and extreme temperatures. The current prototype is made of laser-cut plywood and includes rubber bands, which would become brittle in space. The researchers will have to make something sturdier for testing outside the ISS, likely designed to attach to the end of a robot arm.Back on Earth, Cutkosky also hopes that they can manufacture larger quantities of the adhesive at a lower cost. He imagines that someday gecko-inspired adhesive could be as common as Velcro.

A close-up of the robotic gripper, designed to grab objects in zero gravity using a gecko-inspired adhesive. | Image credit: Kurt Hickman

A team of researchers tested their gripper in multiple zero-gravity settings, including the International Space Station.

How a gecko-inspired robotic gripper can help clean up space debris

Inside the Autonomous Robotic Manipulation (ARM) Lab, massive KUKA robotic arms select and delicately transfer the correct beanbag from a pile of random objects. Photo: Robert Coelius

It’s one thing for a robot to sort through a pile of rigid objects like blocks, but what about softer stuff?

The beanbag test

Soft robotics has made leaps and bounds over the last decade as researchers around the world have experimented with different materials and designs to allow once rigid, jerky machines to bend and flex in ways that mimic and can interact more naturally with living organisms. However, increased flexibility and dexterity has a trade-off of reduced strength, as softer materials are generally not as strong or resilient as inflexible ones, which limits their use.Now, researchers at the&nbsp;<a href="http://seas.harvard.edu/" target="_blank">Harvard John A. Paulson School of Engineering and Applied Sciences</a> (SEAS), the <a href="http://wyss.harvard.edu/" target="_blank">Wyss Institute at Harvard University</a> and MIT&rsquo;s Computer Science and Artificial Intelligence Laboratory (CSAIL) have created origami-inspired artificial muscles that add strength to soft robots, allowing them to lift objects that are up to 1,000 times their own weight using only air or water pressure. The study will be published this week in&nbsp;<a href="http://www.pnas.org/content/early/2017/11/21/1713450114.full" target="_blank">Proceedings of the National Academy of Sciences</a> (PNAS).&ldquo;We were very surprised by how strong the actuators [aka, &ldquo;muscles&rdquo;] were. We expected they&rsquo;d have a higher maximum functional weight than ordinary soft robots, but we didn&rsquo;t expect a thousand-fold increase. It&rsquo;s like giving these robots superpowers,&rdquo; said Daniela Rus, the Andrew and Erna Viterbi Professor of Electrical Engineering and Computer Science at MIT and one of the senior authors of the paper.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1569469584573-Origami-inspired+artificial+muscles+snake+arm.jpg" style="width: 766px;" class="fr-fic fr-dib">The movement and shape of the artificial muscles is defined by the shape of their internal &ldquo;skeleton&rdquo; &ndash; in this case, made of notched blocks of foam. (Image courtesy of the Wyss Institute for Biologically Inspired Engineering)&nbsp;&ldquo;Artificial muscle-like actuators are one of the most important grand challenges in all of engineering,&rdquo; said <a href="https://www.seas.harvard.edu/directory/rjwood" target="_blank">Robert J. Wood</a>, corresponding author of the paper and&nbsp;the Charles River Professor of Engineering and Applied Sciences at the SEAS. &ldquo;Now that we have created actuators with properties similar to natural muscle, we can imagine building almost any robot for almost any task.&rdquo; Wood is also a Founding Core Faculty member of the Wyss Institute.Each artificial muscle consists of an inner skeleton&nbsp;that can be made of various materials, such as a metal coil or a sheet of plastic folded into a certain pattern, surrounded by air or fluid and sealed inside a plastic or textile bag that serves as the skin.&nbsp;A vacuum applied to the inside of the bag initiates the muscle&rsquo;s movement by causing the skin to collapse onto the skeleton, creating tension that drives the motion. No other power source or human input is required to direct the muscle&rsquo;s movement; it is determined entirely by the shape and composition of the skeleton.&ldquo;One of the key aspects of these muscles is that they&rsquo;re programmable, in the sense that designing how the skeleton folds defines how the whole structure moves. You essentially get that motion for free, without the need for a control system,&rdquo; said first author Shuguang Li, a Postdoctoral Fellow at the Wyss Institute and MIT CSAIL. This approach allows the muscles to be very compact and simple, and thus more appropriate for mobile or body-mounted systems that cannot accommodate large or heavy machinery.&ldquo;When creating robots, one always has to ask, &lsquo;Where is the intelligence - is it in the body, or in the brain?&rsquo;&rdquo; said Rus. &ldquo;Incorporating intelligence into the body (via specific folding patterns, in the case of our actuators) has the potential to simplify the algorithms needed to direct the robot to achieve its goal. All these actuators have the same simple on/off switch, which their bodies then translate into a broad range of motions.&rdquo;The team constructed dozens of muscles using materials ranging from metal springs to packing foam to sheets of plastic, and experimented with different skeleton shapes to create muscles that can contract down to 10 percent of their original size, lift a delicate flower off the ground, and twist into a coil, all simply by sucking the air out of them.Not only can the artificial muscles move in many ways, they do so with impressive resilience. They can generate about six times more force per unit area than mammalian skeletal muscle can, and are also lightweight; a 2.6-gram muscle can lift a 3-kilogram object, which is the equivalent of a mallard duck lifting a car. Additionally, a single muscle can be constructed within ten minutes using materials that cost less than $1, making them cheap and easy to test and iterate.<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1569469620868-Origami-inspired+artificial+muscles+white+muscle.jpg" style="width: 766px;" class="fr-fic fr-dib">The zig-zag pattern of this muscle&rsquo;s interior &ldquo;skeleton&rdquo; allows the muscle to contract down to a fraction of its original width. (Image courtesy of the Wyss Institute for Biologically Inspired Engineering) These muscles can be powered by a vacuum, a feature that makes them safer than most of the other artificial muscles currently being tested. &ldquo;A lot of the applications of soft robots are human-centric, so of course it&rsquo;s important to think about safety,&rdquo; said Daniel Vogt, co-author of the paper and Research Engineer at the Wyss Institute. &ldquo;Vacuum-based muscles have a lower risk of rupture, failure, and damage, and they don&rsquo;t expand when they&rsquo;re operating, so you can integrate them into closer-fitting robots on the human body.&rdquo;&ldquo;In addition to their muscle-like properties, these soft actuators are highly scalable. We have built them at sizes ranging from a few millimeters up to a meter, and their performance holds up across the board,&rdquo; said Wood. This feature means that the muscles can be used in numerous applications at multiple scales, such as miniature surgical devices, wearable robotic exoskeletons, transformable architecture, deep-sea manipulators for research or construction, and large deployable structures for space exploration.The team was even able to construct the muscles out of the water-soluble polymer PVA, which opens the possibility of robots that can perform tasks in natural settings with minimal environmental impact, as well as ingestible robots that move to the proper place in the body and then dissolve to release a drug. &ldquo;The possibilities really are limitless. But the very next thing I would like to build with these muscles is an elephant robot with a trunk that can manipulate the world in ways that are as flexible and powerful as you see in real elephants,&rdquo; said Rus.

Origami-inspired artificial muscles are capable of lifting up to 1,000 times their own weight, simply by applying air or water pressure. (Image courtesy of the Wyss Institute for Biologically Inspired Engineering)

Origami-inspired muscles are both soft and strong, and can be made for less than $1

Artificial muscles give soft robots superpowers

Even octopuses understand the importance of elbows. When these squishy, loose-limbed cephalopods need to make a precise movement &mdash; such as guiding food into their mouth &mdash; the muscles in their tentacles contract to create a temporary revolute joint. These joints limit the wobbliness of the arm, enabling more controlled movements. &nbsp;&nbsp;<a href="http://seas.harvard.edu/" target="_blank">Now, researchers from the Harvard John A. Paulson School of Engineering and Applied Sciences</a> (SEAS) and the&nbsp;<a href="http://wyss.harvard.edu/" target="_blank">Wyss Institute for Biologically Inspired Engineering</a> have shown how a multi-layered structure can allow robots to mimic the octopus&rsquo;s kinematics, creating and eliminating joints on command. The structure can also allow robots to rapidly change their stiffness, damping, and dynamics.The research was published in two papers in&nbsp;<a href="https://onlinelibrary.wiley.com/doi/10.1002/adfm.201707136" target="_blank">Advanced Functional Materials</a> and&nbsp;<a href="https://ieeexplore.ieee.org/document/8141952/" target="_blank">IEEE Robotics and Automation Letters.</a>&ldquo;This research helps bridge the gap between soft robotics and traditional rigid robotics,&rdquo; said Yashraj Narang, first author of both studies and graduate student at SEAS. &ldquo;We believe that this class of technology may foster a new generation of machines and structures that cannot simply be classified as soft or rigid.&rdquo;<img src="https://s3-us-west-1.amazonaws.com/wevolver-project-images/froala%2F1569465675108-artistRendering-640x278.jpg" style="width: 766px;" class="fr-fic fr-dib"><div class="inline-image">The structure consists of multiple layers of flexible material wrapped in a plastic envelope and connected to a vacuum source. (Image courtesy of Yashraj Narang/Harvard SEAS)</div>The structure is surprisingly simple, consisting of multiple layers of flexible material wrapped in a plastic envelope and connected to a vacuum source. Without vacuum, the structure behaves exactly as you would expect, bending, twisting and flopping without holding shape. But when a vacuum is applied, it becomes stiff and can hold arbitrary shapes, and it can be molded into additional forms.This transition is the result of a phenomenon called laminar jamming, in which the application of pressure creates friction that strongly couples a group of flexible materials.&ldquo;The frictional forces generated by the pressure act like glue,&rdquo; said Narang. &ldquo;We can control the stiffness, damping, kinematics, and dynamics of the structure by changing the number of layers, tuning the pressure applied to it, and adjusting the spacing between multiple stacks of layers.&rdquo;The research team, which also included&nbsp;<a href="https://www.seas.harvard.edu/directory/howe" target="_blank">Robert Howe</a>, the Abbott and James Lawrence Professor of Engineering,&nbsp;<a href="https://www.seas.harvard.edu/directory/jvlassak" target="_blank">Joost Vlassak</a>, the Abbott and James Lawrence Professor of Materials Engineering, and Alperen Degirmenci, a graduate student in SEAS, extensively modeled the mechanical behavior of laminar jamming to better control its capabilities.Next, they built real-world devices using the structures, including a two-fingered gripper that, without vacuum, could wrap around and hold onto large objects and, with a vacuum, could pinch and hold onto small objects about the size of a marble.<iframe src="https://www.youtube.com/embed/ecTOd6O9Beg?&wmode=opaque" frameborder="0" allowfullscreen="" class="fr-draggable" style="width: 767px; height: 466px;"></iframe> The researchers also demonstrated the structure&rsquo;s capabilities as shock absorbers by attaching them to a drone as landing gear. The team tuned the stiffness and damping of the structures to absorb the impact of landing.The structure is a proof-of-concept that could have many applications in the future, from surgical robots to wearable devices and flexible speakers.&ldquo;Our work has explained the phenomenon of laminar jamming and shown how it can provide robots with highly versatile mechanical behavior,&rdquo; said Howe, senior author of the paper. &ldquo;We believe that this technology will eventually lead to robots that can change state between soft, continuous devices that can safely interact with humans, and rigid, discrete devices that can meet the demands of industrial automation.&rdquo;

This drone’s landing gear is tuned the stiffness and damping to absorb the impact of landing. (Image courtesy of Yashraj Narang/Harvard SEAS) 

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