Lifeboat Foundation

Mobile robots are now being introduced into a wide variety of real-world settings, including public spaces, home environments, health care facilities and offices. Many of these robots are specifically designed to interact and collaborate with humans, helping them to complete hands-on physical tasks.

To improve the performance of mobile robots on interactive and manual tasks, roboticists will need to ensure that they can effectively sense stimuli in their environment. In recent years, many engineers and material scientists have thus been trying to develop systems that can artificially replicate biological sensory processes.

Researchers at Scuola Superiore Sant’Anna, Ca’ Foscari University of Venice, Sapienza University of Rome and other institutes in Italy have recently used an artificial skin and a deep learning technique that could be used to improve the tactile capabilities of both existing and newly developed robots to replicate the function of the so-called Ruffini receptors. Their approach, introduced in a paper published in Nature Machine Intelligence, replicates the function of a class of cells located on the human superficial dermis (i.e., subcutaneous skin tissue), known as Ruffini receptors.

A team of researchers at ETH Zurich in Switzerland have created an intriguing new exosuit that’s designed to give its wearer an extra layer of muscles.

The suit is intended to give those with limited mobility back their strength — and early trials are already showing plenty of potential, the scientists say.

The soft “wearable exomuscle,” dubbed the Myoshirt, automatically detects its wearer’s movement intentions and use actuators to literally take some of the load off.

Takao Someya and colleagues at the University of Tokyo have developed the first artificial-skin patch that does not affect the touch sensitivity of the real skin beneath it. The new ultrathin sensor could be used in applications as diverse as prosthetics and human-machine interfaces.

“A wearable sensor for your fingers has to be extremely thin,” explains Tokyo’s Sunghoon Lee. “But this obviously makes it very fragile and susceptible to damage from rubbing or repeated physical actions.” For this reason most e-skins developed to date been relatively thick and bulky.

In contrast, the sensor developed by the Tokyo team is thin and porous and consists of two layers (Science 370 966). The first layer is an insulating mesh-like network comprising polyurethane fibres around 200–400 nm thick. The second layer is a network of lines that makes up the functional electronic part of the device – a parallel-plate capacitor. This is made of gold on a supporting scaffold of polyvinyl alcohol (PVA), a water-soluble polymer often found in contact lenses. Once this layer has been fabricated, the PVA is washed away to leave only the gold support. The finished pressure sensor is around 13 μ m thick.

An electrochemically powered artificial muscle made from twisted carbon nanotubes contracts more when driven faster thanks to a novel conductive polymer coating. Developed by Ray Baughman of the University of Texas at Dallas in the US and an international team, the device overcomes some of the limitations of previous artificial muscles, and could have applications in robotics, smart textiles and heart pumps.

Carbon nanotubes (CNTs) are rolled-up sheets of carbon with walls as thin as a single atom. When twisted together to form a yarn and placed in an electrolyte bath, CNTs expand and contract in response to electrochemical inputs, much like a natural muscle. In a typical set-up, a potential difference between the yarn and an electrode drives ions from the electrolyte into the yarn, causing the muscle to actuate.

While such CNT muscles are highly energy efficient and extremely strong – they can lift loads up to 100,000 times their own weight – they do have limitations. The main one is that they are bipolar, meaning that the direction of their movement switches whenever the potential drops to zero. This reduces the overall stroke of the actuator. Another drawback is that the muscle’s capacitance decreases when the potential is changed quickly, which also causes the stroke to decrease.

Materials scientists and bioengineers at the intersection of regenerative medicine and bioinspired materials seek to develop shape-programmable artificial muscles with self-sensing capabilities for applications in medicine. In a new report now published in Science Advances, Haoran Liu and a team of researchers in systems and communications engineering at the Frontier Institute of Science and Technology, Jiaotong University, China, were inspired by the coupled behavior of muscles, bones, and nerve systems of mammals and other living organisms to create a multifunctional artificial muscle in the lab. The construct contained polydopamine-coated liquid crystal elastomer (LCE) and low-melting point alloys (LMPA) in a concentric tube or rod. While the team adopted the outer liquid crystal-elastomer to mimic reversible contraction and recovery, they implemented the inner low-melting point alloy for deformation locking and to detect resistance mechanics, much like bone and nerve functions, respectively. The artificial muscle demonstrated a range of performances, including regulated bending and deformation to support heavy objects, and is a direct and effective approach to the design of biomimetic soft devices.

Soft robotics inspired by the skeleton–muscle–nerve system

Scientists aim to implement biocompatibility between soft robotic elements and human beings for assisted movement and high load-bearing capacity; however, such efforts are challenging. Most traditional robots are still in use in industrial, agricultural and aerospace settings for high-precision sensor-based, load-bearing applications. Several functional soft robots contrastingly depend on materials to improve the security of human-machine interactions. Soft robots are therefore complementary to hard robots and have tremendous potential for applications. Biomimetic constructs have also provided alternative inspiration to emulate the skeleton-muscle-nerve system to facilitate agile movement and quick reaction or thinking, with a unique body shape to fit tasks and perform diverse physiological functions. In this work, Liu et al were inspired by the fascinating idea of biomimicry to develop multifunctional artificial muscles for smart applications.

Researchers at ETH Zurich have developed a lightweight, wearable textile exomuscle that uses sensors embedded in its fabric to detect a user’s movement intentions and chip in extra force as needed. Initial tests show a significant boost in endurance.

Where powered exoskeletons act as both muscle and bone, providing force as well as structural support, exomuscles make use of the body’s own structure and simply chip in with additional force. As a result, they’re much lighter and less bulky, but they’re also limited in how much force they can deliver, since human bones and joints can only take so much.

Continue reading “Wearable muscles offer an impressive upper-body endurance boost” »

AZoRobotics speaks with Dr. Erik Enegberg from Florida Atlantic University about his research into a wearable soft robotic armband. This could be a life-changing device for prosthetic hands users who have long-desired advances in dexterity.

Typing on a keyboard, pressing buttons on a remote control, or braiding a child’s hair has remained elusive for prosthetic hand users. How does the loss of tactile sensations impact limb-absent people’s lives?

Losing the sensation of touch has a profound impact on people’s lives. Some of the things that may seem simple and a part of everyday life, such as stroking the fur of a pet or the skin of a loved one, are a meaningful and fundamental way to connect with those around us for others. For example, a patient with a bilateral amputation has previously expressed concerns that he might hurt his granddaughter by accidentally squeezing her hand too tightly as he has lost tactile sensation.

From there, they ran flight tests using a specially designed motion-tracking system. Each electroluminescent actuator served as an active marker that could be tracked using iPhone cameras. The cameras detect each light color, and a computer program they developed tracks the position and attitude of the robots to within 2 millimeters of state-of-the-art infrared motion capture systems.

“We are very proud of how good the tracking result is, compared to the state-of-the-art. We were using cheap hardware, compared to the tens of thousands of dollars these large motion-tracking systems cost, and the tracking results were very close,” Kevin Chen says.

In the future, they plan to enhance that motion tracking system so it can track robots in real-time. The team is working to incorporate control signals so the robots could turn their light on and off during flight and communicate more like real fireflies. They are also studying how electroluminescence could even improve some properties of these soft artificial muscles, Kevin Chen says.

A University of Minnesota research team has made mind-reading possible through the use of electronics and AI.

Researchers at the University of Minnesota Twin Cities have created a system that enables amputees to operate a robotic arm using their brain impulses rather than their muscles. This new technology is more precise and less intrusive than previous methods.

Continue reading “Making Mind Reading Possible: Invention Allows Amputees To Control a Robotic Arm With Their Mind” »