Tag Archives: arm

The gecko-gripper mounted a modified robotic arm at JPL, shown here lifting 45 lbs (20kg). Credit: JPL.

Gecko-inspired adhesive allows robots to grip wider range of objects

The agile gecko is one of nature’s best climbers — and its secret lies in the adhesive pads that line the feet. Now, researchers have combined the gecko toes’ adhesive properties with air-powered soft robotics to achieve unprecedented gripping sensitivity.

The gecko-gripper mounted a modified robotic arm at JPL, shown here lifting 45 lbs (20kg). Credit: JPL.

The gecko-gripper mounted a modified robotic arm at JPL, shown here lifting 45 lbs (20kg). Credit: JPL.

On a gecko’s toe, there are millions of microscopic hairs, each about 20 to 30 times smaller than a human hair. These hairs interact with molecules on the surface that the gecko is trying to grip at the atomic level, generating so-called van der Waals forces, which allow the toes to easily attach and detach when the gecko wills it.

Researchers at the University of California, San Diego, have devised an artificial version of the gecko toes’ microscopic features by employing synthetic materials and a technique called photolithography. In a three-step process, researchers first made a master mold of the millions of microscopic structures that line the gecko’s toes. Later, copies of the master mold were made using a low-cost, scalable method. A process called spin coating allowed the researchers to make as many copies of the adhesives sheets from the wax mold as they wished, at a rate of 10 to 20 sheets per hour. The soft robotic gripper itself was cast in 3D-print molds from a silicone-based rubber.

The team, which collaborated with NASA’s Jet Propulsion Laboratory, coated the 3D-printed fingers of a soft robotic gripper with the artificial gecko adhesive, which remarkably retained many of the same properties of its living, breathing counterpart.

During a series of experiments, the gecko-inspired adhesive allowed an air-powered robotic hand to grip a wide range of objects, from pipes to mugs. The adhesive was also strong and versatile enough to allow the robot to grasp objects at many different angles. The gripper also manipulated volcanic rocks whose porous and rough texture has always been challenging for gecko-like adhesives to cling to.

The gripper can also porous objects, like this volcanic rock. Credit: JPL.

The gripper can also porous objects, like this volcanic rock. Credit: JPL.

Because van der Waals forces are most effective on a larger surface area, the researchers had to develop control algorithms that allow the robot to distribute the right amount of force along the length of the finger. Thanks to optimal control and distribution of load, the gripper can lift various objects, in various positions, weighing up to 45 lbs (20kg).

“We realized that these two components, soft robotics and gecko adhesives, complement each other really well,” said Paul Glick, the paper’s first author and a Ph.D. student in the Bioinspired Robotics and Design Lab at the Jacobs School of Engineering at UC San Diego.

There are various applications that this research could enable. Since NASA was involved, one obvious area of interest is space exploration, where gecko-inspired adhesives might enable janitor-bots to collect trash or new grippers can attach to objects outside the International Space Station better and safer than ever before. Upcoming research will further investigate the adhesive’s potential for operation in zero-gravity.

The artificial hand made at Cornell University was able to tell apart tomatoes by their softness and find the ripest one. Credit: Cornell University.

Optics-based tech lends a human touch to soft robot arm

The artificial hand made at Cornell University was able to tell apart tomatoes by their softness and find the ripest one. Credit: Cornell University.

The artificial hand made at Cornell University was able to tell apart tomatoes by their softness and find the ripest one. Credit: Cornell University.

A new kind of robotic arm based on stretchable optical waveguides boasts unprecedented pressure and texture sensing. Modeled on the human arm, the prosthesis has sensors embedded inside it allowing it to ‘feel’ whether a fruit is ripe or more pressure can be exerted, for instance.

“Most robots today have sensors on the outside of the body that detect things from the surface,” said Cornell doctoral student Huichan Zhao. “Our sensors are integrated within the body, so they can actually detect forces being transmitted through the thickness of the robot, a lot like we and all organisms do when we feel pain, for example.”

Elastomeric optical waveguides are tubes packed inside with LEDs and photosensors. Using a combination of soft lithography and 3-D printing, Zhao and colleagues made the core through which light propagates and the cladding which houses the LED and the photodiode.

The fabrication method had been previously used by Cornell researchers to make all sorts of soft and malleable artificial body parts that resembled tentacles and even a squishy robo-octopus. The four fingers and the thumb are pneumatically actuated and mounted on a 3D-printed rigid palm.

Human-like interactions were tested against various objects. Credit: Cornell University.

Human-like interactions were tested against various objects. Credit: Cornell University.

As the elastomeric tubes get bent, the light’s intensity shone by the LEDs and measured by the photodiode can increase or decrease. It’s this variable loss of light intensity that allows the prosthesis to sense its environment.

Most robotic prostheses are very rigid, held together with nuts and bolts, and sense their surroundings with sensors that conduct electrical signals. Now, a whole new range of possibilities is opened to science because we can use light just as well and soft robotics closely mimics human hands. Such machines can stretch, twist, scrunch and squish, change shape or size, wrap around objects and perform tasks impossible by rigid robotics standards. In fact, it seems there’s a soft robotics revolution just waiting to happen.

“If no light was lost when we bend the prosthesis, we wouldn’t get any information about the state of the sensor,” said lead author Robert Shepherd, assistant professor of mechanical and aerospace engineering. “The amount of loss is dependent on how it’s bent.”

The prosthesis was put to the test with various tasks. In one experiment, the soft arm was able to scan three tomatoes and determine, by softness, which was the ripest.

Shepherd says the artificial soft arm could be made for as little as $50 (batteries and compressor tank not included).

The next step is to have the prosthesis interface with the brain so that a human can control it solely with thoughts. Elsewhere, in manufacturing plants or automated environments, this robot hand could handle special assembly lines or assist humans with its soft touch.

The findings were reported in the journal Science Robotics

Paralyzed man becomes the first person to feel physical sensations through a prosthetic hand directly connected to his brain

A 28-year old who has been paralyzed for more than a decade following a spinal cord injury has become the first person to be able to “feel” physical sensations, through a special prosthetic developed by DARPA – the Defense Advanced Research Projects Agency, a US agency responsible for the development of emerging technologies, mostly for military purposes. The prosthetic hand is connected directly to his brain, allowing him to feel sensations in it.

“We’ve completed the circuit,” said DARPA program manager Justin Sanchez. “Prosthetic limbs that can be controlled by thoughts are showing great promise, but without feedback from signals traveling back to the brain it can be difficult to achieve the level of control needed to perform precise movements. By wiring a sense of touch from a mechanical hand directly into the brain, this work shows the potential for seamless bio-technological restoration of near-natural function.”

This is not the actual prosthetic DARPA used. The volunteer’s identity has been kept secret for privacy reasons. Image via Tech Times.

Electrodes were placed into the volunteer’s cortex, and a special array was placed on his motor cortex, the part of the brain responsible for movements. Then, wires from his motor cortex were connected to a mechanical hand developed by the Applied Physics Laboratory (APL) at Johns Hopkins University. Firstly, this allowed him to move the hand with his thoughts – a remarkable achievement, but something which had already been done.

But then, DARPA breached new ground. They provided the volunteer with a sense of touch! The prosthetic hand contains a vast and sophisticated array of torque sensors that can detect when pressure is being applied, and can convert those physical sensations into electrical signals which are then passed on directly to the brain. In other words, they gave the patient a sense of touch in his 3rd, prosthetic arm.

The feeling, he reported, was as if his own hand was being touched. When blindfolded, the volunteer could determine which finger on the hand was touched with nearly 100% accuracy. Even when the team tried to trick him, he caught on to it.

“At one point, instead of pressing one finger, the team decided to press two without telling him,” said Sanchez, who oversees the Revolutionizing Prosthetics program. “He responded in jest asking whether somebody was trying to play a trick on him. That is when we knew that the feelings he was perceiving through the robotic hand were near-natural.”

Restoring memories

Image via io9

The restoration of sensation is one of several neurotechnology-based advances emerging from DARPA’s 18-month-old Biological Technologies Office, Sanchez said.

“DARPA’s investments in neurotechnologies are helping to open entirely new worlds of function and experience for individuals living with paralysis and have the potential to benefit people with similarly debilitating brain injuries or diseases,” he said.

This is tightly connected to another DARPA project, restoring memories (especially to soldiers and veterans).

“Traumatic brain injury (TBI) is a serious cause of disability in the United States. Diagnosed in more than 270,000 military service members since 2000 and affecting an estimated 1.7 million U.S. civilians each year, TBI frequently results in an impaired ability to retrieve memories formed prior to injury and a reduced capacity to form or retain new memories following injury,” their website reads.

The end goal of this project is to develop a wireless, fully implantable neural-interface medical device that would allow humans to retrieve memories currently inaccessible to them, which to me, is simply mind blowing. We’ve reached a stage where we can not only create prosthetics we can control with our hands, but we can also create sensations in them, and we can tap into how our brain accesses memories. These are truly remarkable times we are living in.

 

$42,000 Prosthetic Hand OutPerformed By $50 Printed Cyborg Beast

Over the last few months, we’ve written a lot about some fantastic 3D designs which can be very useful in medicine – a cranium replacement, 3D printed skin, and especially bone and limb prosthetics. Now, 3D universe, a website dedicated to 3D printing, published an article comparing a $42.000 conventional prosthetic, with a $50 3D printed one.

Jose Delgado was born without his left hand, and in his 53 years, he’s tried several options to support his disability, recently moving onto more advanced prosthetics. For over a year, he had been using a $42,000 myoelectric prosthetic device, which took signals from the fibers in his forearm and translated them into electric signal, moving the fingers of the prosthetic hand. He was lucky enough – his insurance covered the costs, but most people in the world don’t have this luxury.

Jeremy Simon of 3DUniverse met up with Jose, and printed him a 3D prosthetic from Cyborg Beast. These are the open source 3D printed hands – anyone can take the design for free and print his or her own prosthetic. It’s really worth checking out if you or someone close to you is suffering from such a disability. At $50 for materials, it’s a very affordable financial effort.

It seems really weird to compare one thing to the other – there is a huge price difference (840 times) – both Delgado and Simon were understandably skeptical – but after testing them both, Delgado declared that the $50 one was easily outperforming the counterpart he had been using for over a year. Sure, it’s a little bit more frail, and it will probably break sooner rather than later, but the solutions is simple – you just print a new one! 3D printing is really changing the world – and it’s doing so at lower and lower prices.