Grab a rubber band and stretch it just far enough to wrap it around a deck of cards — now you understand the trick behind the newest breakthrough in materials science: a simple concept with a serious impact on reduction in lead-based materials.
A group of U.S researchers recently published a study in Nature Communications showing that by putting the right amount of strain on an ultrathin film of sodium niobate (a harmless, lead-free material), they could cajole it into exhibiting some impressive electrical capabilities, the likes of which are usually only typical of high-performance, lead-based materials.
By controlling the stretch, they created small sections where two crystal structures can exist side-by-side.
The electric dispersion can easily twist, rotate and switch between multiple states, giving the material exceptional tunability and fast, reliable switching without adding complex chemical ingredients or harmful lead.
This makes it perfect for future memory chips, sensors and wireless tech.
Using powerful tools like synchrotron X-rays and advanced electron imaging, the researchers observed the crystal phases come to life and confirmed the unusual behavior.
The results indicate a promising path toward greener, safer high-performance electronics that don’t compromise on power.
The first step in building any robot is to decide what you want it to do. While most of the robot’s abilities will be unlocked with clever machine learning and artificial intelligence algorithms, you need to set your robot up for success with the right mechanical features.
LISTEN TO THE DEEP DIVE
For a human eyeball, nice and round, turn to embedding light-sensitive receptors directly onto the surface of a 3D sphere like the team from the Hong Kong University of Science and Technology, UC-Berkeley and the Lawrence Berkeley National Laboratory.
You could also add a narrow bandgap semiconductor as a photosensing material — then your robot could see in the dark with infrared light sensing. In lieu of realism, you could turn to any number of sensors to have your robot “see”:
Distance sensors and gauges – maybe an ultrasonic range finder or laser measurement sensor. Positioning sensor – room navigation or indoor localization might come in handy. A GPS system or other live tracking devices will help your robot find its way around.
Thermal imaging sensors or pressure sensors are also an option.
Facial recognition – that’s some machine learning pre-programming.
LEGS
Want to jump? Forget biomimicry. Researchers at the UC Santa Barbara use an actuator system based on elasticity. It’s a spring with rubber bands and carbon fiber slats used to shoot the bot into the air.
Or keep the biomimicry but add hydraulic systems and electric motors a la Boston Dynamics’ Atlas.
You could leave humanity behind and go the marsupial route. German engineering firm Festo took it one further and developed the BionicKangaroo.
A “tendon” in its robotic leg drives it forward and captures energy on landing. The impact drives the legs into position for the next leap on its spring-loaded legs.
GRAPHICS: Abjad Design
Stanford University engineers developed a “stereotyped nature-inspired aerial grasper” or SNAG, bird-shaped feet that can perch on any branch.
WINGS
Go classic with drone design and choose rotary wings that spin to create lift and thrust like a helicopter. These are best for hovering, vertical takeoff and changing direction quickly.
Maybe you’d rather the classic plane look and have room for a runway or launcher. Fixed wings generate lift by moving through the air and offer higher speed, longer endurance and greater stability, though your robot will be at the mercy of the weather conditions.
You could even turn to the flapping wings of insects and birds. There are complex transmission systems using gears and motors available from the Harvard team that developed a solar-powered tiny robot styled after a honey bee. A team at the University of Bristol developed a tiny flying robot that flaps its wings more efficiently than an insect, using an electrostatic “zipping” mechanism (their words).
HANDS
What kind of hand does your robot need? Do you want the classic gripper, optimized for delicacy or accuracy? Or is a suction cup plenty?
How many joints does your robot arm need? You’re not limited by human anatomy here.
Many robot hands come with sensors packed into their fingertips only, but an MIT team built a robotic finger with sensors providing continuous sensing along the finger’s entire length, allowing it to accurately identify an object after grasping it just one time.
Researchers at Columbia Engineering developed a highly dexterous robot hand that can operate in the dark. It uses tactile sensors rather than vision to manipulate objects.
Virtual reality has given us the sensations of sight and sound, but now engineers have created a sensory fingertip to mimic the sense of touch.
The team of Chinese researchers used the practical example of being able to virtually pet a cat. They said that one of the motivators of this project was the isolation of COVID-19 lockdowns and the possibility to, at least virtually, hug a family member.
While previous technology consisted of bulky gloves, the fingertips, similar to the thickness of human skin, let the wearer feel pressure, vibration and textures. By adjusting the frequency and voltage of the signal, they are able to mimic the roughness of certain textures like sandpaper or rocks or the smoothness of silk or glass. The results were published in the September 2022 edition of Science Advances.
This technology could be used on gloves to assist the likes of firefighters, astronauts or deep-sea divers whose bulky, insulated safety suits interfere with the sense of touch, the team says.
It is very hard to mimic the feeling of sustained pressure without vibration.
– Weikang Lin, researcher
Weikang Lin, the lead researcher on the paper, discusses the challenge of simulating the sensation of holding a mobile phone: If it is held for a time, sustained pressure will be felt, but if it starts to vibrate, the vibration will be felt and the pressure ignored. “It is very hard to mimic the feeling of sustained pressure without vibration,” Weikang tells KUST Review.
A common weakness of electrical-based stimulators is the inability to precisely stimulate one kind of receptor without activating others, says Zhengbao Yang, one of the researchers on the project. “In our future work, we want to overcome this challenge.”
The team also envisions a Braille tool for the visually impaired or a virtual shopping experience whereby the shopper can feel the fabric of the clothes.
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