Recently, researchers at MIT revealed miniature artificial muscles with light-emitting properties. What challenges do tiny robotic systems face, what have MIT researchers created, and how will artificial muscles be the way forward for robotics?
What challenges do tiny robotic systems face?
Robotics systems have come a long way since the introduction of electronics in mechanical designs, yet robotic systems are still grappling with many tasks. One such challenge is creating human-sized bipedal robots that can move like humans. Boston Dynamics has demonstrated such robots, but their movement is somewhat rigid and they often fall over. Moreover, robotic hands still cannot match the dexterity of the human hand, and this is due to the use of large motors and the difficulty of developing sensors that behave like human skin.
Another challenge facing robotic systems is miniaturization. Trying to create a fly-sized robot that has 6 legs, wings, and cameras is impossible with current technology because the cameras are too big, the batteries are too heavy, and the motor systems can’t be made small enough. to power a pair of thin wings that can generate enough lifting force.
A striking difference between living organisms and robotics is that while robots focus on motors, living organisms use muscles. Unlike motors, a muscle can only pull, which is why there are often two pairs of muscles (one to pull a joint outward and another to pull the joint inward). Muscles are also extremely energy efficient compared to electric motors (62% vs. 25%), meaning they can run on smaller amounts of power. Considering that a muscle has no moving mechanical parts, it makes sense that they would be easier to integrate into smaller, space constrained designs.
But the challenge with muscles is that they require precise control often achieved with the use of a brain, whereas motors are much easier to drive. Additionally, muscles need a constant supply of oxygen and nutrition, which means that any design that plans to use organic muscles must also supply other organ systems such as a circulatory system. As such, organic muscles are never found in robotic systems, which means that making miniature robots is still in the realm of scientific research.
MIT researchers create artificial light-emitting muscles
Recognize the benefits of muscles, MIT researchers recently developed artificial muscles that can be electrically controlled while having light-emitting properties. To create the muscles, the team took layers of ultra-thin elastomer, then embedded carbon nanotube electrodes which are then rolled into a cylinder. Applying voltage causes the electrodes to compress, causing the muscle fiber to pull inward.
The electroluminescence of the muscles was obtained by integrating particles of zinc sulphate into the elastomer. Thus, applying high voltage to muscle fibers causes them to emit light, and the researchers further demonstrated the capabilities of light-emitting muscles by spelling out the words MIT.
The artificial muscles were then used to create a small robot with four pairs of wings providing flight capabilities. The researchers then took advantage of the muscles’ light-emitting abilities to enable rudimentary communication and tracking via an iPhone. Additionally, the use of four different colors (one for each pair of wings) allowed for 2mm tracking accuracy (close to that of state-of-the-art infrared tracking systems).
Are artificial muscles the way forward in robotics?
When creating robotic systems, it makes sense to imitate life for the simple reason that life has found efficient and reliable methods for movement. However, the challenge of improved robotic dexterity may not come from using motors but the lack of touch sensors and algorithms capable of processing large amounts of data in real time.
As such, future larger robotic systems may rely not on artificial muscles, but on artificial skin with thousands of touch and pressure sensors. The processing of this information would require the use artificial networks integrated into controllersand so it may be that robotics that imitate life require a brain more than anything else.
There’s no doubt that artificial muscles are the way to go in microelectronics, but they could also be the answer for larger robots trying to mimic the human body.