When we first started working on stabilization technologies for hand tremors several clever users from reddit suggested that we experiment with using a chicken to provide more stability when eating. While this won't work that well (I’ll leave practical issues to your imagination), they did bring up a good point. Chickens, as recently popularized online, are able to keep their heads remarkably still. Many of you might have seen Mercedes' commercial for their electronic suspension.
If you want to get your groove on, you can watch the full Mercedes ad.
How do the chickens keep their heads so still, and why?
The answer lies within an ancient story. Early vertebrates, including dinosaurs, evolved something called a Vestibular system, which over the millennia was passed down to us humans - you have one in each ear. This system is an extremely sophisticated input that our brain uses to process our orientation. It helps us vertebrates balance, track our food, and move quickly.
What’s amazing is that this sensor provides our brains with the exact same information that engineers use to stabilize motion. In fact, both animals and modern controllers consist of:
- Embedded sensors that capture motion in 3 dimensions
- Brain or controller to processes signals from the sensors and determines when corrective action is needed.
- Actuators or muscles that generate counteracting motion. They must be very fast-acting.
In biological systems, the sensors in our ears are able to detect rotation and acceleration in three perpendicular directions, each independent of one another. What’s fascinating is that engineers have developed ways to do get this exact information using synthetic motion sensors. These also detect movement in three perpendicular axes (mathematicians call these mutually orthogonal directions). Modern synthetic sensors (like the ones we use at Lift Labs) transmit electronic signals to our on-board computers, which control actuators that stabilize the unwanted motion.
Key to effective motion cancellation is fast response. For birds, who are particularly good at stabilization, this is critical because their flight takes place in 3-D, requiring quick updates on orientation. To accomplish this, most birds’ vestibular systems are much larger than other animals their size. The amount of brain processing dedicated to their system is also nearly double.
You probably never noticed it, but humans possess something called VOR (Vestibulo-ocular Reflex) that allows us to visually track an object even though our heads might be moving. This is an open-loop reflex (it still works in the dark with no visual feedback) because visual processing takes too much time. Remember, fast response is key. With VOR, our eyeballs physically move whenever our heads move to compensate for any disturbance.
In addition to VOR, birds (like chickens) have something called a vestibulo collic reflex (VCR). This stabilizes the head as well as the eye, and is crucial when much larger disturbances like flapping flight occur. Fast-response muscles (actuators) exist in the neck to constantly adjust the head in real-time.
It’s amazing how quickly our technology is improving. Already we can provide very effective systems (like the Liftware and others) to stabilize tremor from neurological disorders like Essential Tremor or Parkinson’s Disease. While not perfect, Liftware can provide some very effective stabilization, and future products will only improve from here. Soon we’ll be able to surpass what biological systems can do.
You can see how far we've come just with Liftware: