It was witnessing the marvel of modern technology that prompted Science Fiction writer Arthur C Clarke to say that “any sufficiently advanced technology is indistinguishable from magic”. Seeing somebody glide through the streets on a self-balancing scooter might seem like witchcraft. But before we pull out our pitchforks, let’s take a closer look at what really makes these crafts tick.
Keeping a hover-board balanced is like spinning plates. First you need to find the center of balance which will keep the plate upright. Moving forwards or backwards will shift the gravitational center, causing the plates to fall. To keep it upright, we have to compensate for that shift by using equal counter-movements.
To keep our plates spinning we need to know two basic principles. The first is the center of balance. The second is how that center is affected by motion in order to compensate for it.
The inner-workings of a hover-board are almost identical. Minute changes in weight distribution are measured. That information is then sent to the engines which increases or decreases output to keep you upright.
These processes happen in a fraction of a second which makes it seem like magic; it’s actually the result of lightning fast mathematics.
Like spinning plates, a hover-board needs to know where the center of gravity is. This information comes from two pieces of technology: the first is a gyroscope. The second is an accelerometer.
The nervous system: Gyroscopes and Accelerometers
A self-balancing scooter is ancient knowledge in modern housing. Gyroscopes were invented thousands of years ago and have been used for everything from proving the earth is round to keeping 747’s in the air.
A complex looking device, gyroscopes are made up of three rotating bands, an axis and a spinning rotor.
If you’ve ever wondered how your smart phone knows which way it’s facing and flips the screen accordingly, the answer is micro electrical mechanical semi-conductors (MEMS), or in a simpler language, mini gyroscopes.
Gyroscopes detect the position of an object in relation to the floor by measuring gravitational pull. These mini-gyroscopes are so small that they can be fitted inside a micro-chip. This allows hover-boards to know exactly where its center of gravity is. But adding motion to the mix requires a different set of tools. These are known as accelerometers.
Three accelerometers are fitted into a single chip and measure motion in six different directions. The combination of MEMS with accelerometers allows a hover-board to measure where it is in relation to the floor as well as what direction it’s travelling.
The magic of modern technology is its ability to take those measurements and use them to make adjustments in real time. For that, it uses software.
Intuitive software is what separates a responsive, agile hover-board from a jerky piece of junk. Incorporating gyroscopes and accelerometers is hard to get wrong, but designing software to interpret that information is much more difficult.
All hover-boards feature a logic board; sometimes referred to as a mother-board. The most important part of the logic board is the speed of its processor. As the name suggests a processor processes the measurements sent to it by the gyroscope and accelerometers.
Using the information provided, processors conducts complex equations in a fraction of second. They figure out which direction the board is moving in and where the center of gravity is. They then use that information to increase, or decrease the power of the engines, keeping you upright- similar to how we counter-balanced our spinning plates.
If the sensors or MEMS are cheaply made then they will struggle to deliver accurate information, in real-time to the logic board. Equally if the processor or software is poorly designed it won’t interpret those measurements in the right way. Finally, a poorly built logic-board won’t be able to adjust engine torque accurately enough to counter balance you.
Each component has to work in perfect harmony in order to deliver a smooth ride. If anyone one of them is out of sync you’ll find your hover-board is jerky, vibrates, or doesn’t respond correctly to your movements. If we think of the logic board as the brain, then the brawn is most certainly the engines.
The muscle- electric motors
Electric motors are nothing new. You’ll find them in your refrigerator, dishwasher or air-conditioning unit. Using bar magnets, electricity charges each magnet which repel one other to create kinetic energy.
Generally speaking, the more power you apply to the motor, the more energy it creates and the faster you’ll go. On a hover-board, the key component is torque (https://www.physics.uoguelph.ca/tutorials/torque/Q.torque.intro.html) which is the efficiency of a craft in using that energy to generate motion.
A 1000W hover-board , for example, won’t necessarily be faster or better on hills than a 500W motor. The size of the wheels, the way power is transferred via chain, pulley or gear shaft as well as the tires themselves will all play a role in how much torque you’re getting.
Although electric motors have remained relatively unchanged since the nineties, the surrounding technology has developed making them increasingly viable. I am, of course, talking about lithium batteries.
The heart- lithium batteries
The drive of phone manufacturers to develop smaller and smaller devices has in many ways given birth to the lithium battery. These small batteries have become increasingly efficient, requiring very little time to recharge.
Lithium ion batteries, and the even more efficient silicon-based lithium batteries, have given a new lease of life to electric motors. Although, not as efficient as traditional lead acid batteries, they are much safer, much lighter and much quicker to charge.
Pulling it together
The last component of the hover-board, and perhaps the most important, is you. The foot-controls, which are now standard on most transport devices, were developed by Shane Chen . They use infrared light as a circuit breaker. When you lean forward the light is cut-off increasing power to the engines, when you lean back the opposite happens.
The intuitive, and innovative, control system is what makes hover-boards so popular. But it’s the coming together of a range of technology that’s made them successful. Whenever you ride a hover-board a myriad of measurements, interpretations and forces are combining in perfect harmony. The final piece of that puzzle is you, who controls and navigates the craft using your core muscles.
As with any new industry, there are great products which try to develop the industry, and there are products which are just designed to make a quick-buck. The complexity of these systems means that if one link is out of joint the whole chain is compromised. To truly appreciate this marvel of modern technology, you have to be willing to invest in the best. Cheaper products undermine an exciting industry that has the potential to transform our concept of travel.
Contributed by Author: James Flynn