Tag Archives: Balance

A robot near you might soon have a tail to help with balance

New research from the Beijing Institute of Technology wants to steal the design of one of nature’s best balancing devices — the tail — and put it in robots.

A schematic outlining the design of the self-balancing robot tail. Image credits Zhang, Ren & Cheng.

Nature has often faced the same issues that designers and engineers grapple with in their work, but it has had much more time and resources at its disposal to fix them. So researchers in all fields of science aren’t ashamed of stealing some of its solutions when faced with a dead end. Over the past decades, roboticists have routinely had issues in making their creations keep their balance in any but the most ideal of settings. The humble tail might help break that impasse.

Tail tale

The bio-inspired, tail-like mechanism developed by the team can help their robot maintain balance in dynamic environments, the authors explain. The bot is made up of the main body, two wheels, and the tail component. This latter one is controlled by an “adaptive hierarchical sliding mode controller”, a fancy bit of code that allows it to rotate in different directions in an area parallel to the wheels.

In essence, it calculates and implements the tail motions needed to ensure the robot remains stable while moving around its environment.

There’s obviously some very complex math involved here. The authors explain that their system uses estimates of uncertainty in order to guide the tail. This is based on a theorem called the Lyapunov stability theorem, a theoretical framework that describes the stability of systems in motion. The tail then moves in specific patterns that are designed to increase the robot’s stability.

Most approaches to the issue of balancing two-wheeled vehicles today rely on collecting a vehicle’s body altitude data using an inertial measurement unit (IMU), a device that can measure forces acting on the robot’s body. This data is then processed and the results are used to determine a balancing strategy, which typically involves adjusting the robot’s tilt. These, the authors explain, typically work well enough — but they wanted to offer up an alternative that doesn’t involve tilting the robot’s body.

So far, the tail’s performance has only been evaluated in computer simulations, not in physical ones. However, these found it to be “very promising”, as it was able to stabilize a simulated robot who lost its balance within around 3.5 seconds. The team hopes that in the future, their tail will be used to make new or preexisting robot designs even more stable

The authors are now working on a prototype of the robot so that they can test its performance.

The paper “Control and application of tail-like mechanism in self-balance robot” has been published in the Proceedings of 2020 Chinese Intelligent Systems Conference.

Arque tail.

Robotic, seahorse-inspired tail can help people maintain balance through sickness or hard work

Three graduates from Keio University’s (Japan) graduate school of media design have created a bio-inspire robotic tail — that you can wear.

Arque tail.

Arque, the new robotic tail.
Image via Youtube / yamen saraiji.

If you’ve ever envied your pet‘s tail, Junichi Nabeshima, Yamen Saraij, and Kouta Minamizawa have got you covered. The trio designed an “anthropomorphic” robotic tail based on the seahorse’s tail that they chirstened ‘Arque’. The device could help extend body functions or help individuals who need support to maintain balance.

Tail-ored for success

Most animals rely on their tails for mobility and balance. While our bodies lack the same ability, the team hopes that Arque can help provide it. The authors explain in their paper that “the force generated by swinging the tail” can change the position of a person’s center of gravity. “A wearable body tracker mounted on the upper body of the user estimates the center of gravity, and accordingly actuates the tail.”

The tail is constructed out of several individual artificial vertebrae around a set of four pneumatic muscles. The team notes that they looked at the tail of seahorses for inspiration when designing the tail’s structure.

“In this prototype, the tail unit consists of a variant number of joint units to produce,” the trio told The Telegraph. “Each joint consists of four protective plates and one weight-adjustable vertebrae.”

“At each joint, the plates are linked together using elastic cords, while the vertebrae are attached to them using a spring mechanism to mimic the resistance to transverse deformation and compressibility of a seahorse skeleton, and also to support the tangential and shearing forces generated when the tail actuates.”

Arque’s modular design means that its length and weight can be adjusted to accommodate the wearer’s body. Apart from helping patients with impaired mobility, the tail could also be used in other applications, such as helping to support workers when they’re moving heavy loads.

The team also has high hopes for Arque to be used for “full-body haptic feedback”. Just as the tail can be used to change the center of mass and rebalance a user’s posture, it can be employed to generate full body forces (depending on where it’s attached to the body) and throw them off balance — which would help provide more realism to virtual reality interactions.

Arque’s intended use is to be worn, but one has to take into account personal experience and social interactions when predicting whether this will work or not. How likely would it be for people to feel comfortable putting one on, or wearing them outside? Most people definitely enjoy gadgets but, as the smart-glasses episode showed us, they need to perceive it as ‘cool’ or they won’t ever succeed. Whether or not a robotic tail will ever be as socially acceptable as a cane remains to be seen but.

In the meantime, it definitely does look like a fun tail to try on.

The tail was presented at the SIGGRAPH ’19 conference in Los Angeles. A paper describing the work “Arque: Artificial Biomimicry-Inspired Tail for Extending Innate Body Functions” has been published in the ACM SIGGRAPH 2019 Emerging Technologies journal.

Inner ear diagram.

We finally found the protein that turns sound and balance into electrical signals

Researchers have pinpointed the protein that turns sound and head movement into nerve signals for the brain.

Inner ear diagram.

An embroidered diagram of the inner ear.
Image credits Hey Paul Studios.

A team from the Harvard Medical School believe they’ve ended a 40-year-long search for the protein that allows us to hear and stay upright. Nestled in the inner year, this molecule turns sound and movements of the head into electrical signals — it is, in effect, what translates them into a language our brain can understand.

Ear-round signaling

The team points to TMC1 (Transmembrane channel-like protein 1), a protein discovered in 2002, as being the elusive molecule researchers have been looking for. TMC1 folds in on itself in such a way as to form a sound-and-motion-activated pore. In effect, it acts much like a microphone: the protein turns pressure waves into electronic signals, a process known as ‘auditory transduction’. These are then fed to the brain, where they’re recreated into sound and help us maintain balance.

The findings come to fill in a gap in our understanding of how hair cells in the inner ear convert sound and movement into signals for the nervous system.

“The search for this sensor protein has led to numerous dead ends, but we think this discovery ends the quest,” said David Corey, Bertarelli Professor of Translational Medical Science at Harvard and co-senior author on the study.

“It is, indeed, the gatekeeper of hearing,” says co-senior author Jeffrey Holt, a Harvard Medical School professor of otolaryngology and neurology at Boston Children’s Hospital.

The team hopes that their findings can lead to precision-targeted therapy for hearing loss associated with malformed or missing TMC1 proteins.

Hearing is one of the very few senses whose molecular converters remained unknown. This was, in part, due to the position of the inner ear. Nestled in the skull, the densest bone in the body, this organ is hard to reach. To further complicate matters, it also houses relatively few sensory cells that can be retrieved, dissected, and imaged. Our inner ear houses roughly 16,000 auditory cells — a human retina, by contrast, boasts over a hundred million sensory cells.

The team’s research was based on the discovery of the TMC1 gene in 2002. Back in 2011, a team led by Holt proved that TMC1 was required for transduction, but whether it was is a key player or just a supporting actor in the process. So, naturally, it sparked a heated debate among researchers.

Step-by-step process

The current paper aimed to put this debate to rest. In an initial set of experiments, the team found that TCM1 proteins clump together in pairs to form ion channels (basically pores). It was quite a surprising discovery, as most ion channels are built from three to seven proteins, the team explains. However, this unusual pairing also helped the researchers make sense the protein’s structure.

The second step was to map out the protein’s 3D structure. Computer predictive modeling, a process that works by predicting the most probable arrangement of a protein’s atoms based on comparisons with similar proteins with known structures, was used. This approach is based on the fact that a protein’s functions are dictated by its structure, i.e. its specific arrangement of amino acids.

The algorithm revealed that TMC1’s closest relative with known structure was a protein known as TMEM16, and yielded a possible amino acid model for TMC1.

Finally, the team set out to confirm whether the computer model was onto something or not by using mouse models. The team substituted 17 amino acids — one at a time — in the hair cells of living mice and then noted how each alteration changed the cell’s ability to pick up on sound, movement, or the flow of ions (i.e. electrical signals).

Eleven of the substitutions altered the flow of ions, five of them having a dramatic effect (reducing flow by up to 80%), the team reports. One substitution blocked the flow of calcium ions completely.

“Hair cells, like car engines, are complex machines that need to be studied as they are running,” says Corey. “You can’t figure out how a piston or a spark plug works by itself. You have to modify the part, put it back in the engine and then gauge its effect on performance.”

Another strong indicator that TMC1 is central to hearing is that it’s found in all vertebrates — mammals, birds, fish, amphibians, and reptiles.

“The fact that evolution has conserved this protein across all vertebrate species underscores how critical it is for survival,” Holt said.

The paper “TMC1 Forms the Pore of Mechanosensory Transduction Channels in Vertebrate Inner Ear Hair Cells” has been published in the journal Neuron.

How hearing works and other eary functions

I like my ears. I’ve been told they go well with my face, and they’re really good at holding the hair out of my eyes.! Yay for ears!

But (spoiler alert) these are not our ears’ primary functions. The workings of our ears’ internal mechanisms underpin two of our senses — hearing and balance (called equilibrioception).

So, have you ever been to a concert and wondered exactly how is it you can hear that mad riff that has hairs standing up the back of your neck? Or why you get dizzy headbanging to it? Well, we’re here to tell you all about your ears.

Image via Flickr.

Hearing all about it

Our sense of hearing evolved to satisfy our need for a way to survey our environment for predators, prey, and natural disasters. While most of us tend to rely on seeing as our dominant source of information, the sense is not without its limits. The quality of reliable information our eyes feed us deteriorates rapidly as light levels drop, and they can only see a small area in front of us — and even there, it’s pretty easy to hide from or confuse it. Here’s an example:

Somewhere here there’s a snow leopard stalking the goats. Can you find it?

The leopard is literally in plain sight, but it took me around three or four minutes to spot it. And that’s only because I knew it was supposed to be there so I really looked for it. By mimicking the environment, the predator fooled my brain into signing it off as just another pebble or rock. If I relied on my eyes alone, this slope would appear safe and the next thing you know, I’m a leopard’s chew toy.

That’s why hearing is so important. It allows us to keep tabs on our whole environment, 24/7, no matter where we’re looking or what we’re doing. It’s long-range enough to give us time to react to threats and it works basically everywhere.

Except in space.

The sensory organ that handles hearing is the ear. Through them, our brain can pick up pressure waves traveling through air, water or solids by turning the particle motion into sensory input. However, the flappy piece of tissue that most of us call an “ear” is actually an auricle (or pinna in other animals) and it’s just a small part of a much larger and complex mechanism.

The auricle acts like a funnel, capturing sound and directing it into the auditory canal. It also filters sound so only frequencies that you can actually hear are sent to your actual ear.

At the end of this canal, the sound hits the tympanic membrane, a piece of tissue that you might know as the eardrum. The tympanic membrane serves as the limit between the outer and middle ear. The membrane is thin enough that pressure waves cause it to vibrate, and in turn move three tiny auditory ossicles attached to it (the malleus, incus, and stapes).

These bones amplify the sound vibrations and send them to the cochlea, a snail-shaped structure filled with fluid in the bony labyrinth.

Image Wikipediadia

An elastic membrane runs from the beginning to the end of the cochlea, splitting it into an upper and a lower part. It has a hugely important part to play in our hearing; The vibrations from the eardrum apply pressure to the fluids inside the cochlea, causing ripples to form on the membrane.

This membrane houses sensory cells that have bristly structures protruding from them (they’re named hair cells because of this) which pick up on the motion by hitting the upper part of the cochlea. When the “hairs” bend, they open pore-like structures that allow for chemicals to pass through, creating an electrical signal for the auditory nerve to pick up.

But the ear isn’t just about hearing, it’s also the organ that allows us to keep balance. Balance is the ability to maintain the body’s center of mass over its base of support. While achieving this takes a lot of information from the different senses, the ear’s vestibular system feeds our brain vital information about our body’s position and movement. Kinda like our own personal gyroscopes.

3D image of the cochlea and vestibular system.
Image via Wikipedia

The vestibular system is made up of those three semicircular canals you can see in the picture above. They’re placed at a roughly 90 degrees angle to each other and are called the lateral, superior, and inferior canals. Each of them is filled with liquid that flows in response to our body’s movements and pushes on hair cells in a structure called the cupula. Due to their position, each canal is sensitive to one type of movement:

  • The horizontal semicircular canal picks up on head movements around a vertical axis, i.e. on the neck (as when doing a pirouette)
  • The anterior and posterior canals detect rotations on the sagittal plane (for example, nodding) and the frontal plane (as when cartwheeling) respectively. Both anterior and posterior canals are orientated at an approximately 45 degrees angle between the frontal and sagittal planes.

The electrical signals from the cupula is carried through the vestibulocochlear nerve to the cerebellum for processing.

But, as always, both the voices and balance are just…

Products of your brain

Sensory organs are just that, organs that sense stuff. But they can’t make heads or tails of the information they provide, just as a microphone feeds information to your PC but doesn’t understand it by itself.

Hearing and balance also conform to that rule. The brain decodes information received from the ears and processes them mostly in the auditory cortex.

The auditory cortex, shown in pink, with other areas that lend a hand in processing information from our ears colored.

Equilibrium is maintained by the cerebellum (also known as the little brain) by using data from the semicircular canals along with information supplied by other senses.