Tag Archives: technology

Which is more stable, washing machines or birds? The answer might surprise you

What do birds and washing machines have in common? Shockingly, it’s not the ability to wash clothes. Rather, most birds and washing machines are great examples of vibration isolation systems.

Now that’s cool and all – but what is a vibration isolation system?

Better known as a mass-spring-damper system, vibration isolators are generally a mechanical or industrial mechanism that can reduce the amount of vibrational energy produced by a system. Vibration isolators are incredibly important; studies show “undesirable vibrations” can shorten a machine’s service life and even permanently damage the machine and those using it. Considering this, engineers are constantly improving upon current vibration control systems, and are now looking to birds for inspiration.

But why birds? Well, to understand this, let’s consider a bird as a simple mass-spring-damper system.

Avian vibration isolation system represented as mass-spring-damper-system
Simple approximation of avian vibration isolation system as mass-spring-damper system. Taken from the 2015 study: ‘The role of passive avian head stabilization in flapping flight.”

First, visualize vibrations as an oscillating force stemming from the bird’s body moving back-and-forth. Vibrational forces can be generated by the flapping of wings, unexpected gusts, and/or movement of legs. Now, if we continue up from the body to the neck, we can see where avian skeletal and muscular structure really begins to “show off its feathers.”

Characterized as a multi-layered structure, the avian neck contains many sections of “hollow” bones, connected by surrounding muscles. The structural units (muscles and bones) of the avian neck have properties of both springs and dampers, optimizing them for vibration isolation.

Simplified representation of multi-layered neck as spring-damper structure

For starters, we see the muscles largely act as springs. Springs have the unique ability to move a body with its vibrations. This behavior is present in the muscles connected to the bone segments, in that they are capable of instantaneously compressing, elongating and twisting in response to rapid changes in the body’s movement. This elastic response prevents not only the head, but the whole bird, from shaking when bombarded when vibrations from any form of movement.

Simplified visualization of multi-layered spring-damper structure. The transparent grey portion represents the hollow bone, which is connected by the black lines, or strong spring-like muscles. The empty space between each unit would consist of the softer, damper-like muscle. Taken from the 2021 study: “A novel dynamics stabilization and vibration isolation structure inspired by the role of avian neck.”

Alternatively, the muscles, primarily those not connected to bone, can act as dampers. Effective dampers are similarly identified by the ability to move with vibrations; however, they can dissipate some of the vibrational energy as heat, or store energy until relaxed. The interior muscles are capable of slowly deforming (changing shape) if exposed to steady vibrations, allowing for dissipation of excessive vibrational energy.

But hey, what about those bones?

The avian neck has nearly three times the number of bone sections than most mammals, on top of muscles entirely surrounding the neck. This drastically increases the bird’s flexibility, helping it maneuver through sharp positional changes, thereby further limiting the effect of vibrational forces.

Finally, what makes the avian vibration isolator truly superior is its passive activation. As engineers at Shanghai Jiao Tong University point out, manmade passive vibration isolators fall short because they require sensors and input energy to adjust for “shocks and random vibrations.” As previously explained, the multi-layered neck is well equipped to handle random oscillations, yet, more importantly, the bird’s neck muscles can passively change position to brace for incoming vibrations.

A recent study from Stanford University proved this concept by recording a whooper swan’s reaction to different strength gusts. They found that swan’s neck adjusted to protect the head, and that even when the flapping doubled, the movement of the head reduced by a quarter. Finally, it is important to note that passive activation is not limited to the sky; researchers have found that mainly terrestrial birds like chickens and pigeons have a similar neck structure and system for maintaining stability and clear vision.

Overall, continuing to study the avian vibration isolation system could prove very beneficial for many different applications. For a more in-depth look at the current work out, check-out the studies referenced throughout the article. Otherwise, enjoy watching this chicken work its body control magic!

Mercedes-Benz “Chicken” Magic Body Control Advertisement, highlighting the chicken’s amazing head stabilization ability.

sticks and stones may break my bones but dirt will wash right off

There you are, sitting in the park eating your spaghetti picnic on your favorite picnic blanket when your pollen allergy acts up. You let out a sneeze powerful enough to compete with Aeolus’ bag of wind, but now your spaghetti is all over your favorite picnic blanket. You immediately go to rinse it off, but your fine Italian sauce has thoroughly soaked in. If only nature had a solution to keep a surface clean. Enter: the lotus leaf.

The lotus leaf is renowned for its ability to stay clean in murky environments. This characteristic of the plant is regularly attributed to its superhydrophobic surface features and chemistry. A superhydrophobic surface is a surface which can maintain a contact angle with water above 150o and is correlated with a low free surface energy—which really means water pools and rolls off rather than soaking into the surface.

Nearly perfectly spherical water droplet on an artificially prepared surface

Modified from Zorba et al. 2008

A key attribute of the superhydrophobic surface is a hierarchical micro- and nanostructure. The microstructure is composed of plant cells grown in little mounds known as a “papillae” with small channels for air flow in between called “stomata.” The nanostructure is composed of hair-like wax crystal towers (epicuticular wax) built on the peaks of the papillae topography. The elevated wax towers combined with the stomata trap air and reduce the contact area of the water with the surface. The epicuticular wax chemistry reduces the adhesion to the towers themselves by being naturally hydrophobic.

Graphic of water drop resting across uneven wax pillars on a lotus leaf

Modified from Zorba et al. 2008

The tips of the wax towers create the largest repelling forces which form larger contact angles, while shorter towers can actually produce adhesive forces that reduce the contact angle. If the air is displaced and filled with water, the contact angle will decrease due to the water-water adhesion which “pulls” the droplet to the surface. Similarly, if the surface is damaged, the wax can be removed and decrease the surface’s hydrophobicity. The wax is naturally soft material and prone to mechanical damage increasing water adhesion and reducing the self-cleaning abilities of the leaf.

The papillae topography is the key to the robustness of the lotus leaf hydrophobicity. The papillae create natural valleys and creases which—like the tops—are still densely packed with wax hairs. When the surface is impacted, only the top of the papillae are exposed to the mechanical force so the wax tubules in the valleys are left undeformed and maintain their hydrophobic characteristics.

Water beads on rain jacket

Photo by Chase Pellerin via Gear Patrol

Hydrophobic surfaces have many applications in everyday life, for example rain jackets and umbrellas perform their best when they are hydrophobic. Manufacturing processes rely on hydrophobic surfaces to reduce oxidation and stay clean in past-paced environments, and your favorite picnic blanket would be much less prone to spaghetti stains if it were hydrophobic. Nature has solutions to keeping surfaces clean; we just have to recognize them.

This Toner Might Be More Expensive: 3-D Printing Artificial Organs

For most people in the United States who need an organ transplant, they will need to wait an average of three to five years on a list before they can get a lifesaving surgery. On average, 20 people die daily waiting on this list. There is a possibility of being able to bypass the wait time by manufacturing the required organs with 3D printing. This manufacturing technique was first used in the medical field for prosthetics and surgery practice models, with a goal to create fully functioning organs for those in need. Instead of using plastic or printer ink, the 3D printer uses cells to create biological constructions. 

A biological 3D printer making a small model of a human heart
Biological 3D Printing Market Update Photo

Traditional methods of artificial tissue and organ creation involve the use of stem cells, which are cells that do not have a designated purpose yet, to create a scaffold or frame for the organ. If cells for a desired organ are placed on the appropriate scaffold, they could multiply and grow into an artificial organ over time. If 3D printing is implemented using the same scaffold procedure, cells could be placed more precisely; the cell diameter can be better controlled, and the speed of the process can be controlled digitally. All of these aspects allow for better replication of the complex networks and structures found within biological tissues. A major advantage of the 3D printed organs are the customizations and variability that can be implemented with the method. Implants can be made to different sizes to suit each unique individual. If the original cells used for 3D printer material are from the intended recipient, the compatibility of the implant or artificial organ is nearly guaranteed. The risk of organ rejection is always present in the time following a transplant operation. 

A man who received 3D printed skull implants following deformation from a bicycle crash.
Xilloc Medical Before and After Photo

The 3D printing process is near perfect for certain medical uses, such as prosthetics, and dental implants, but more work needs to be done with the printing of tissues and organs. Small simple organs with thin walls can be done but printing larger organs such as hearts and kidneys requires integration of the vascular network, which cannot be done at this time. As printers become more precise and able to use a higher variety of cells, the creation of these vascular networks becomes more and more plausible. 

Scientists are currently investigating a new way to print these complex organs by combining organic material with mechanical chips. These chips are able to replicate certain biological stimuli, including fluid flow and chemical gradients, in order to achieve some degree of organ function within a much simpler biological structure. Using these chips will allow for better mass production of a variety of tissues and organs. This particular technology is being used to create tissues that will be used for testing pharmaceutical drugs. There is an opportunity for these tissues to be expanded to use in the human body, but the majority of companies using this technology are still in the startup phase. 

            While the use of 3D printing to create complex artificial organs is not completely viable today, the technology is improving rapidly. Within a few years, the waiting times and problems with organ transplants could be a thing of the past.  

Using K-Motion Technology to Achieve the Perfect Baseball Swing

The question on every baseball player’s mind is: besides more practice, how can I improve my batting skills?

Most people would assume it comes down to practice and strength training, but according to Joe Lemire, a sports reporter at SportTechie, the answer actually lies in the biomechanics of the swing. An in-depth description of the intricacies of the biomechanics that are involved in a baseball swing can be found in David Fortenbaugh’s dissertation here.

A photo of a baseball player mid-swing, making contact with the ball in a game.
Photo by Chris Chow on Unsplash

Many professional baseball teams and some training facilities, including Driveline Baseball in Seattle, have turned to using a K-Motion vest to record and analyze different aspects of a baseball swing. This wearable technology started as an analysis for golf swings, but the technology has now been implemented in baseball. Initial installations of this technology were much more expensive and not portable, but engineers have found ways to translate these technologies into wearable devices that can be used in more natural situations.

Prior methods of swing analysis left many unanswered questions and didn’t provide athletes with proper information for improvement. The K-Motion vest collects data on the speed and bend in a player’s torso and pelvis, and the rotation of their body. The portability of the vest allows for it to be used in game-like scenarios and provide useful information. The data that can be extracted from the K-Motion vest can be used to fix mechanical flaws in a player’s swing.

A photo of a man wearing the K-Motion vest, showing that a sensor sits on the top of the spine and at the tailbone.
Photo from Lemire, SportTechie 2018 (Courtesy of K-Motion)

The K-Vest uses four different sensors to measure the rotational velocities of the torso, hips, lead arm, and bottom hand. The four sensors are placed above the elbow on the lead arm, on the back of the lead hand, on the tailbone, and on top of the thoracic spine. The velocities are compiled into a graph, and the peak velocity of each sensor can be analyzed to track the transfer of energy throughout the swing. Through use of the K-Vest, they have found that to elevate one’s hitting ability comes down to the transfer of energy from pelvis and torso rotation to their arms and wrists.

In order to fix the mechanics of a swing, the system has to obtain an understanding of what a good swing is by compiling data from a variety of professional players. On the graph produced with each swing, the range for pro hitters is displayed to give the user an idea of how they compare. Some more information about the kinematic analysis of the data can be found here.

An example of the data that the user receives from the system and how it can be used to improve a player’s swing can be seen in this video:

Though already proven useful in baseball and golf, people are finding that it can also be useful in volleyball, running, skiing, and other forms of physical activity. The use of this technology has become much more common as professional players have found the feedback to be constructive.

For more information about this technology, check out K-Motion’s website, and see here how it’s being used in golf.

The Weight of Combat: Are powered exoskeletons the solution to heavy combat loads?

Have you ever wondered how much weight a soldier carries in a combat zone?

Military servicemembers, particularly those in physically demanding roles such as infantry, are routinely required to carry heavy combat loads ranging from 25- to over 100-lbs. This load potentially includes weapons, ammunition, body armor, food, sleeping equipment, and other necessities for the mission. Consider that these loads are often carried for hours or even days at a time in both deployed and non-deployed environments and it becomes clear that these loads take a physical toll on those who bear them.

The physiological demands of these loads often lead to servicemember injury or discomfort both during and after their time in service. The most common musculoskeletal injuries resulting from carrying heavy combat loads include increased lower back pain and injuries to the knee, ankle, and spinal cord. Such injuries lead to acute and chronic effects over the servicemembers’ lifetimes, increased military healthcare costs, and decreased military readiness.

While it would be advantageous to decrease both the weight of the combat load as well as the frequency of weight-bearing events, the reality of modern warfare gives little hope to these suggestions. However, there is another solution: external, electrically powered exoskeletons to aid with carrying combat loads.

American defense and technology company Lockheed Martin is currently developing a prototype exoskeleton for military use – the ONYX exoskeleton. Two prior-service soldiers are shown performing common physical tasks under load – walking up a steep incline and walking up flights of stairs – while aided by the exoskeleton. Both soldiers involved in the test indicated a high level of comfort with the exoskeleton as well as improved weight-bearing ability using the ONYX exoskeleton. Check out the video to learn more:

Powered exoskeletons come with drawbacks, namely mobility/comfort issues and the need for a mobile, long-lasting power source. While the devices may perform well in a laboratory or controlled setting, reliability in the field will require durable materials and electronics. Additionally, while Lockheed-Martin’s ONYX exoskeleton is designed to reduce load on the wearer’s knees and quadriceps muscles, it gives no such support to the lower back or other parts of the body. This shift in load distribution throughout the body may have unintended consequences and potentially lead to further injury. A 2006 study by researchers at Loughborough University in the UK found that existing military load carriage systems result in gait and posture changes (head on neck angle, trunk angle, etc.) which lead to muscle tensions that increase one’s risk for injury.

A figure visualizing the angles made by the head, torso, and legs when walking
Image taken from Attwells et al., Ergonomics, 2006.

Thus, while there have been many improvements in robotic and soft electronics technology in recent years, powered exoskeletons have much to prove before they see time in service.

What do you think – are powered exoskeletons going to be commonplace on the battlefields of tomorrow, or are they a passing fad?

For more information, check out the following articles from the Army Times and Breaking Defense on the ONYX exoskeleton.

Skeletal Support Seekers’ Success (So Far)

Bones break, and broken bones need time to heal, or regrow. Fans of J.K. Rowling’s Harry Potter series are quite familiar with the concept of bone repair, as Harry is once required to drink a Skele-Gro potion to magically (and painfully) regrow his arm bones overnight. Now, as fantastic as it would be to completely fix broken bones in a few hours, modern medicine has not yet discovered that secret of the Wizarding World; however, several treatments have been developed in attempts to speed the rate of fracture repair as well as increase the comfort of the patient (take that, Skele-Gro).

Images of a broken bone and the progression of a callus being formed over time
Image from Cambridge Fracture Clinic

For those unfamiliar with the process of bone repair, a quick overview is in order. In short, inflammation provides stability to a fractured area, and over the course of several weeks fibrous tissue forms a callus around the fracture which is eventually replaced by bone. The mechanical environment at the fracture site is influential in healing, with factors such as hormones, vitamins, minerals, diet, fluid flow, and physical and electrical stimuli affecting healing rates. With these factors in mind, engineers and scientists are attempting to speed bone regrowth.

Low-level laser therapy (LLLT) is one practice found to accelerate bone healing. A study published in Lasers in Medical Science revealed that LLLT stimulates bone cells in fracture areas which increases the rate of callus development. Tests performed on the broken tibial bones of two groups of white rabbits demonstrated that bone mineral density at fracture sites remained higher in the group receiving laser therapy than in the control group throughout healing. 

However, post-mortem tests revealed that bones healed under LLLT endured significantly lower maximum stresses than intact bones or bones healed under normal conditions. This is a controversial result, as other studies have concluded opposite findings, so despite the enhanced growth resulting from LLLT, the authors of this study agree that additional experiments are necessary to satisfactorily settle this issue.

Images of stress concentrations in and around a solid titanium implant and porous titanium implants with various levels of bone ingrowth
Modified from Spoerke, et al., Septermber 2005

Surgical implants are another device used to facilitate bone healing. Most bone implants are made of titanium due to its lightness, durability, and biocompatibility. While these supports effectively immobilize and position bones for proper healing, some patients experience complications later on, largely due to stiffness differences between bone and titanium—resulting stress concentrations increase risk of fracture or implant loosening. Titanium foam implants coated in an organoapatite (OA) layer are a developing solution to this issue, described in detail in an Acta Biomaterialia article.

The porous surface of titanium foam, studied in vitro, substantially decreases implant stiffness, thus enabling stress to be more evenly shared between the foam and surrounding bone. Allowing bone ingrowth into the pores also reduces stress concentrations at the materials’ interface which helps alleviate risk of implant failure. Furthermore, the OA coating on the foam stimulates bonding between bone tissue and the implant, thereby increasing stability. The success of these studies suggest that titanium foam is ready for in vivo testing. 

Check out this video on the advantages of titanium foam:

Although the results of these fracture repair treatments are still a far cry from those achieved with Skele-Gro, further research and development regarding bone regrowth may lead to significant advances in the very near future. Interested in learning more? Check out articles on other developing fracture treatment technologies here and here.

Robots Could Soon Replace Human Stunt-Doubles

Imagine an aerial acrobat soaring fifty feet above your head and executing gravity-defying stunts during a live performance. After your initial amazement that a human could be performing acts such as these so fearlessly, you look a bit closer to realize that the performer is actually not human at all. Thanks to a groundbreaking technology recently developed by Disney Research, this could soon become a reality.

Stuntronics robot soaring through air while holding heroic pose
Photo from Walt Disney Imagineering Research and Development, 2018

Over the past year, Disney has been working to produce a robotic stuntman that has the ability to replace its human counterpart in performing dangerous aerial acrobatics. This seamless blend of biomechanics and technology has the potential to ultimately create an immersive and unforgettable entertainment experience.

This project, known as “Stuntronics,” originated from a smaller research project known as Stickman. Stickman was a robot that consisted of a line of three metal rods connected by two flexible joints. Once cast into the air by swinging off a pendulum wire, the robot utilized sensors such as accelerometers and gyroscopes to relay to its microcontroller (or brain) information regarding its position and orientation while flying through the air. Using all of this information from the sensors, the robot then either tucked or untucked its sections to rotate more or less quickly, respectively, in order to land flat and untucked on its back. A diagram explaining the robot’s motion can be found below.

Diagram of Stickman robot's trajectory through the air with labels
Photo from Christensen et al., Disney Research 2018

In order to scale Stickman to a more lifelike and human-sized robot, it was necessary to take a closer look at the science behind how human performers are able to execute their movements. Researchers Spiros Prassas, Young-Hoon Kwon, and William Sands explored these questions in a review focused on the biomechanics of gymnastics.

An important part of acrobatics and gymnastics is the ability to shift angular momentum (the amount a body rotates) between body parts. As a gymnast gets closer to the ground, they can either speed up or slow down their rotation by rotating their arms in order to successfully stick a landing. Performers also are able to speed up or slow down their rotation by manipulating their moment of inertia (the amount a body resists rotating more quickly or slowly) through their body configuration. For example, if the performer needs to speed up their rotation, they could reduce their moment of inertia by tucking into a ball, whereas if they wanted to slow down, they could untuck their body into a full layout.

The Stuntronics robot utilizes these concepts by continually reading the feedback from all of its attached sensors and lasers to tell the entire body which configuration it should be in at any given time. After being launched in an arc from a swinging wire, it is capable of controlling its pose in order to either speed down or speed up its rotation, and thus land perfectly each time (see video below).

This advanced technology could be pushed to the limit to ultimately produce more engaging and immersive entertainment by carrying out stunts that would simply be too dangerous for human performers to attempt. In a world where robots are constantly being implemented to take the place of humans in performing dangerous, dirty, and tedious work, Stuntronics could serve as a foundation for generations of robots, both stuntmen and non-stuntmen, to come.

For further reading, check out these articles from TechCrunch and Popular Science.

 

The future of hearing might be in your bones

 

How many times have you walked up to someone and were unable to get their attention because they had headphones on? This is an increasingly important issue as we become more connected to our devices and less connected to the world around us. Recently, several companies, including Aftershokz and Pyle, have tried to solve this issue by creating bone conducting headphones.

How does bone conduction work?

diagrams of the inner ear displaying the differences in bone and air conduction
Modified from Furuichi, GoldenDance 2008

 

Although these devices may seem futuristic, bone conduction has been used for hundreds of years, especially in applications involving music. In the 18th century, Beethoven, although he had lost much of his hearing, was able to listen to his music by clenching a rod in his mouth that was attached to his piano. In most situations, we hear sounds using air conduction in our ears. Our outer ear channels vibrations that travel through the air into our ear canal where our eardrum transmits these vibrations to our cochlea. Inside the cochlea, each frequency resonates at a different location along the basilar membrane, and these mechanical waves are converted into neural signals that are transmitted to the brain. Bone conduction works by sending these vibrations through our bones directly to the cochlea and bypassing the outer ear and eardrum.

How is bone conduction used?

Szweda, BAE Systems 2015

As time and technology have progressed, bone conduction has become increasingly more common in commercial devices. Currently, the most prevalent use of bone conduction is in hearing aids for those suffering from outer or middle ear damage. Bone conduction is also used in applications where users must still be aware of their environment while listening to music or other sounds. Modern devices are able to transmit frequencies between 20 and 20,000 Hz. This range is perfect for listening to music and voices at reasonable volumes. Bone conduction can also be used in more demanding situations. BAE Systems has utilized bone conducting technology to manufacture helmets that allow soldiers on the battlefield and sailors competing in America’s Cup to communicate with each other while still being able to hear their environment. These grueling environments make perfect use of bone conducting device’s durability in hazardous conditions including water and dust.

What is the future of bone conduction?

image of LG G8 smartphone depicting the cystal sound OLED speaker screen
LG G8 Smartphone, LG Electronics 2019

Although many devices that utilize bone conduction like Google Glass and Zungle Audio sunglasses have not yet become mainstream. This technology still has a bright future. On February 24, 2019, LG unveiled its G8 smartphone which eliminated its top speaker for receiving phone calls. Instead, LG’s design creates sound by vibrating its front glass panel. The user can then press the screen against his or her face conducting the sound through his or her cheek to better hear the person on the other line. As implementations like these become more common, the technology behind bone conduction will only get better. It may seem like the future, but the next headphones or pair of sunglasses you buy might have bone conducting technology inside of it.

 

For more information on this story, check out The Verge and CNN.