Fullscreen HTML5Med Res (??MB)HTML4

Look mum: no hands! It’s the by Ross Tester AirWheel What has one wheel, no handlebars, no “apparent” controls but is enormous fun to ride once you get the hang of it? An accelerometerstabilised and microprocessor-controlled AirWheel, that’s what! SILICON CHIP recently took one for a spin – literally! Y ou must have seen the Segway – and wondered how anyone could ride such a gravity and balance-defying device. Yet people – many people – have mastered the art. So much so that you now even see TV cameramen zipping up and down the football sidelines on their Segways – no doubt saving their own energy but just as importantly, giving a smooth, jerk-free picture back to the director. Well, if you thought the Segway (with its two wheels) was gravity and balance-defying, folks, you ain’t seen nuthin’ yet! Here comes the Airwheel! The first thing you notice about the Airwheel is that there is only one wheel. (In truth, there are models with twin wheels but they’re only a couple of centimetres apart so in our book, that qualifies as one!) The second thing you notice about the Airwheel is that, unlike the Segway (and imitators) there is nothing to hang on to – no handlebars, no balance straps, nothing. 14  Silicon Chip The third thing you notice about the Airwheel is that it looks impossible to ride – until you see someone glide by without (apparently) a care in the world. You’ll see Airwheel riders with a bit of practice under their belts riding with hands in pockets, hands on hips, hands anywhere except spread right out grasping for balance! There are even plenty of videos of riders with one foot in the air . . . The Airwheel comes in a variety of models, which are all variations on a theme. And there are other similar devices on the market such as the Solowheel and the Electric Unicycle. But we’ll concentrate on the Airwheel, mainly because we got to have a play with one for a week or so, courtesy of Airwheel Australia! OK, what is an Airwheel? In a nutshell, it’s a battery-powered, microprocessor and gyroscopically-controlled single wheel personal transportation device. It has a pair of foot supports (they call them pedals, but they don’t pedal anything!) emerging from siliconchip.com.au each side; to ride it you simply step on it and go! To move forward, you transfer some of your weight forward. To slow down, stop or even go backward, you transfer some of your weight backward. To go left . . . you’ve guessed it – you transfer some of your weight to the left (and similarly to go right). The manufacturers describe it as “incorporating the latest in fuzzy software, posture control, motion control, anti-electromagnetic interference and a gyroscope.” Breaking open the nutshell, the Airwheel is battery powered and has a maximum speed (depending on model, which in turn depends on which battery is fitted) of about 12-18km/h or so. In fact, where legal (see panel overleaf), 12km/h is usually the maximum speed allowed. It has three-way gyroscopic control to maintain balance and direction with a number (again depending on model) of accelerometers to sense the rider’s weight transfers. A microprocessor takes over then to apply power to the pancake-type electric motor, which is basically the entire wheel. A Lithium-ion or Lithium Phosphate rechargeable battery of between 130 and 340Wh (depending on model) will give around 15-21km or so range, although this depends on both the weight being carried (maximum 120kg) and the inclines you try to traverse. We’ve seen figures quoting 15-30° maximum on the largest models but we find even the lower figure a bit hard to believe: the ramp up to the first-floor SILICON CHIP offices is about 10° and we couldn’t get the Airwheel up that! Battery life is rated at up to 1600 charge/discharge cycles. The motors are rated at up to 800W and drive wheels up to 36cm in diameter Where do they come from? The Airwheel is designed and manufactured in Changzhou, China but some references say it was invented in Resplendent in floppy hat and sunnies (safety equipment, no doubt) our intrepid Editor got the hang of the Airwheel within minutes (albeit with trainer wheels fitted), zooming around the carpark. This is the two-wheeled model – it’s slightly easier to learn to ride than the one-wheel model shown at left in carried “transportation” mode. siliconchip.com.au February 2015  15 OK, so he’s showing off . . . but this rider ably demonstrates the stability of the airwheel, thanks to its gyroscopes, accelerometers and microprocessor. COILS MAGNETS (ONE PER COIL) Inside the AirWheel motor: you can see the 56 coils around the edge of the rotor (which remains stationary!), with 56 very powerful magnets alongside around the stator. The tyre goes on the outside of the stator, shown assembled above. England. There is now world-wide distribution for the Airwheel and any number of organisations are advertising it, even on ebay. Weight and portability There are quite a few Airwheel models available (see opposite) but all have one thing in common – their portability. They’re touted as being ideal for riding to the station and carrying onto a train. At 10-15kg, we say “good luck” – that’s quite a weight to tote up and down station stairs etc – or even carry for any significant distance. Possible, yes. Practical? Ummm . . . which either attracts or repels the magnets. So the stator moves either toward or away from the coils . But by the time the stator reaches the point where equilibrium would be reached, power has been switched to the next coil, and then the next, and the next – resulting in the motor turning forward or reverse, always attempting to maintain that magnetic balance but never achieving it while ever power is applied. Rather than running on DC straight from the 60V battery, the Airwheel is driven by a three-phase inverter through its microprocessor-powered controller – what this means is much more power available from the motor for the amount of voltage applied. Just as importantly, it enables very good speed control over the motor, an important consideration when your only means of control is small shifts in body weight! Safety features Learning to ride the Airwheel is at best a little daunting because it goes against everything your brain tells you about balance and stability. For this reason, detachable “trainer wheels” are supplied which fit as outriggers and help the new rider board the Airwheel and commence to ride. Even so, the first hour or so is likely to be an on/off, stop/start affair. Gradually, though, you’ll learn that the Airwheel is actually assisting you The motor Like most small electric-motorpowered people movers, the Airwheel uses a brushless DC motor (BLDC), also known as a pancake motor. Unlike most electric motors, where (as you would expect) the rotor spins and the stator remains stationary, in this pancake motor the rotor remains rigidly fixed to the frame and the stator spins. In the Airwheel, the stator actually forms the wheel halves, so it provides the power to move. The motor has 56 very powerful magnets firmly positioned around the outside of the stator and 56 matching coils attached to the rotor. The microprocessor switches power to the appropriate coils at the appropriate time, resulting in a magnetic field 16  Silicon Chip The AirWheel controller board. The three pairs of MOSFETs at the rear provide the 3-phase drive for the motor – the rest of the circuitry keeps the wheel stable. siliconchip.com.au by countering the natural tendency to tip over. We’ve already mentioned the microprocessor and gyroscopic control. There’s an automatic speed controller built in to some models, whereby the front of the foot platform rises above 12km/h to prevent further acceleration. This also actuates when the battery level falls to 10% of capacity – in this case the Airwheel decelerates to a complete stop. A sensor will stall the motor when the Airwheel inclines more than 45°. Battery and charging The battery is inbuilt and is charged by a switch-mode charger which plugs into the standard 230VAC power point. It takes about 90 minutes to charge completely; 80% charge is achieved in 60 minutes. We found that with intermittent use, the battery life is very good – we didn’t need to recharge for the whole week we were playing researching. In use With the training wheels fitted (they can be removed quickly) we found MODEL X3 X5 X6 X8 Q1 Q3 Q5 MOTOR 400W 500W 600W 800W 800W 800W 800W BATTERY 132Wh 132Wh 132Wh 170Wh 132Wh 170Wh 340Wh SPEED 19km/h 19km/h 19km/h 19km/h 19km/h 19km/h 19km/h DISTANCE 9-12km 11-15km 12-16km 16-23km 11-15km 16-26km 38-45km UNIT WEIGHT 9.8kg 9.8kg 11.5kg 11.5kg 13kg 13kg 13kg CHARGE TIME 1h 1.5h 1.5h 1.5h 1.5h 1.5h 2h MAX WEIGHT 120kg 120kg 120kg 120kg 120kg 120kg 120kg 355mm 355mm 405mm 405mm 355mm* 355mm* 355mm* TYRE SIZE * twin wheel riding the AirWheel relatively easy. In fact, our Editor suggested that once you got the hang of it, the trainer wheels should come off to make turning easier. But none of us were game to take up his suggestion! The lack of any handle or leash is a bit unnerving to start off with, after all, every instinct tells you that the damn thing should topple over as soon as you place one foot on it! And standing there with two feet on it and it moving away underneath you, well, that’s just crazy stuff, isn’t it? But after a few minutes of leaning on someone else’s shoulders for support, you find you don’t need them! Where from, how much Our Airwheel came from Airwheel Australia, of Frenchs Forest NSW. As mentioned earlier, there are numerous models available, ranging in price from about $750 to $1100. The one we trialled was one of the Airwheel Q3 models, which has a recommended retail price of $1099 including GST. Contact Airwheel Australia via their website: www.air-wheel.com.au SC Where can they be used? That question opens a real can of worms because the way the laws are written in at least the major Australian states, they cannot legally be used virtually anywhere, except on private property. In fact, they’re specifically excluded under NSW (and we believe most other states) legislation. They come under the “prohibited vehicles” section of the Act, which says “These types of devices must not be used on roads or in any public areas such as footpaths, car parks and parks.” Motorised human transporters (MHTs) such as the WheelMan or Segway are specifically mentioned. Ref www.rms.nsw.gov.au/ roads/registration/unregistered.html The legislators haven’t quite caught up with the AirWheel yet! SILICON CHIP believes this is very short-sighted legislation and to some degree, appears to be the result of lobbyists trying to ensure a particular product was legal and nothing else! Or perhaps it is simply that technology has once again significantly overtaken the lawmakers. Of course, there are already many users who do ride MHTs in public places, either ignorant of the law, don’t care, or assume they can outrun any pursuer on foot (perhaps they can!). Indeed, in other parts of the world, Governments have been much more proactive in recognising the potential of these devices in assisting in the movement of people, whether that’s to and from public transport hubs or indeed the whole journey. They recognise the potential of personal people movers and their ability to reduce the number of other vehicles on the road. Back in Australia, the Queensland government showed significantly more foresight than NSW and Victoria by legalising human transporters, at least on public paths, on August 1 2013, providing users wear a helmet. Incidentally, section 244L of the Queensland siliconchip.com.au traffic laws demands they be fitted with a bell. Ummm – where! Motorised human transporters are rapidly gaining favour on university campuses with both students and staff having to get from point A to point B as efficiently and effectively as possible. They’re being used by staff moving around large warehouses and distribution centres and by supervisors traversing large assembly lines quickly and easily. AirWheel have even been in discussions with large housing estate developers who would like to keep motor vehicles outside the housing areas – eg, park on the outskirts and AirWheel to your house on the pathways provided! Far fetched? At the moment maybe, but wait a year or two . . . February 2015  17