British science fiction writer Arthur C. Clark said that…
Any sufficiently advanced technology is indistinguishable from magic.
At first glance of a self-balancing scooter that might be true. But once you take a closer look, the magic of the hover-board is simply the expansion of a science that was invented several hundred years ago. The technology may have got smaller, but the basic principles remain the same.
Understanding The Anatomy Of A Hoverboard
To help visualize how a self-balancing device works think about balancing a broom using just one hand. First, you have to find the center of the brooms balance. As it swings you may have to adjust your movements to keep it steady. Now, try and run forward holding the broom. The additional forces of movement will unbalance the broom further but, so long as you can compensate for those forces, you can keep the broom balanced.
To balance the broom you need to know two things. First, where the center of gravity is moving, and second, how to compensate for that. The foot-panels on a hover-board work in much the same way. Minute changes in weight distribution are detected and sent to the motor which provides counter power to the wheels to keep you upright.
Similar to broom balancing, in order to keep you upright, the hover-board has to know where the center of gravity is. This knowledge comes from two pieces of technology. The accelerometer and a gyroscope.
The Nervous System: GyroScopes & Acceleromoters
A gyroscope is a complex looking device made up of three circular rotating bands, an axis and a spinning rotor. The science is not particularly new and is used in everything from bicycles to navigating air-crafts.
What is new is the tiny gyroscopes that can be fitted into computer chips. Have you ever wondered how smart phones know which way they are facing and automatically flip the image to be the right way up? The answer is micro electro mechanical semi conducters (MEMS) or mini gyroscopes; and they’re just one technology that personal transport devices are indebted to mobile phone developers for.
With the help of MEMS hover-boards are able to detect their position in relation to the floor. Unfortunately, they can’t detect whether or not they are in motion. That comes from accelerometers. Three of these can be fitted into a chip with the ability to measure motion in six directions.
Combining the information of the accelerometers, which measure movement, with the gyroscope, which measures gravitational position, allows the device to measure its precise movements in relation to its environment. The real wonder of modern technology is its ability to interpret those movements which comes from software.
The Brain: Logic Boards & Software
The software on these devices is what separates good products from bad ones. The physical components are easy enough to copy but the right control software is extremely difficult to replicate without resorting to pirating. This is one of the reasons why a knock-off hover-board will feel jerky or respond in odd ways to changes of movement.
All hover-boards are fitted with a logic board, sometimes referred to as a motherboard. The main component of the logic board is the processor. This measures the data from the accelerometers and MEMS in real-time adjusting torque instructions to the motor and keeping you balanced.
If the processor, or MEMS are cheaply made, then the relay of information will be slower and less responsive. Also, if your hover-board has a training mode, then the logic board is what sets limiters to handling responsiveness, acceleration and power.
The relationship between the logic board, sensors and motor is what keeps you balancing. When the MEMS and accelerometer detect your center of gravity shifting, the processor sends information to the motor to increase, or decrease, power. Similarly, when you increase speed by exerting pressure via the foot panels the logic board will send a request for more power from the motors.
The logic board is the brain of the device, but the brawn comes from the electric motors. These motors are usually contained within the wheels. This is why all hover-boards have dual motors. When you turn, more power is sent to one motor, or wheel, than the other causing you to spin. Inefficient calibration between the motors can be the reason for poor control, vibrating or jerking movements.
The Muscle: Electric Motors
Electric motors are not new technology and you can find them everywhere. Your fridge uses an electric motor, as does your washing machine. The technology relies on two bar magnets which, when given an electric charge, will attract or repel each other. This causes circular motion which can be used to power wheels.
As a rule of thumb, a more powerful motor results in a faster board. Although, other aspects such as torque, or the efficiency of using that power, can effect performance as well. A 1000W motor with poorly made wheels will not be as effective as a smaller motor with efficient parts.
The electric motor has stayed much the same since the nineties, although advances in chain drives, pulleys and gear shafts has made them more efficient. The reason that electric motors are coming into their own in the 21st century is the technology that’s developing around them- not least of which the Lithium battery.
The Heart: Lithium Batteries
As I mentioned earlier, the personal transport industry is indebted to the phone industry for much of its technology. The drive to produce smaller, thinner and lighter components in-line with trends led to significant research into battery technology. The result was the lithium ion battery and, in recent years, the even more efficient silicon-based Lithium battery.
Lithium battery technology is what made electric powered personal transport devices viable. The traditional lead acid battery is still the most economical but it requires a lot of space. Space equals more weight and electric engines, which are less powerful than their petrol alternatives, struggle to contend with the weight of lead acid batteries.
Lithium-ion batteries are portable and lightweight with the capability of delivering a decent charge. They also take just a few hours to charge between rides. Modern hover-boards can feature quick replaceable batteries which are small enough, and light enough, to carry in your rucksack.
Pulling It All Together
The last component of a hover-board, but perhaps the most important, is the foot controls. These were developed by Shane Chen, the father of modern self-balancing scooters. They use infrared light to tell the motor to engage or not. When you press forward the infrared light is cut-off engaging the motor, when you lean back it reconnects reducing power.
The innovative control system is what makes these products so desirable and easy to use. But it’s really a combination of all the technology that has made them so successful. Hover-boards rely on a perfect harmony of several key features. The MEMS and accelerometers have to be working in tandem to stay up right. The processing chip in the logic board has to be powerful enough to process the data in real-time, whilst the engine has to be responsive enough to adjust torque at the drop of a hat.
All of these processes happen in the blink of an eye and, to the casual observer, it might seem like magic. In fact, it’s the rapid development of portable technology, like smart-phones, that has ushered in a new era of legitimate, green powered personal transport. The final part of the equation is the rider, who adjusts their core muscles whilst remaining balanced, to operate the control system.
With such a myriad of processes the drive for quality is important. If even one component is out of sync it can mess with the whole system. This is a well-documented issue in the hover-board community with the product recall of 2016 as well as unhappy customers with hover-boards that don’t work or have poor controls.
To experience this technology properly you have to be willing to invest in legitimate brands. Hover-boards are available at rock-bottom prices but these will likely have imperfect systems, or poorly made components. These tend to de-legitimize the industry as a whole. Investing a little more in a well-made, professional hover-board will make a world of difference to your riding experience and will probably work out cheaper in the long run. As 2017 closes out, we’ve already seen some fantastic developments in safety and performance which promises an excellent 2018 for the hover-board industry. Stay up to date with the latest news here.