Motorcycle Monitor

For motorcyclists, few thoughts provoke more terror than theidea of flying headlong over the handlebars. Under those circumstances, they'reat the mercy of velocity and impact, as well as the free-body forces that aregenerated when flesh and bones strike asphalt surfaces, concrete curbs andoccasional moving vehicles.

The goodnews, however, is that one clothing manufacturer understands the physics of thesituation, and has a solution. The Bering Co., a Frenchfirm that specializes in wearable motorcycle gear, has rolled out a jacket thatdoubles as an airbag. Send it a firing signal and the jacket will puff up with21 l of compressed helium, cushioning the cyclist's body before it strikes thebone-breaking surfaces.

"We can'tstop the accidents, but we can provide the drivers with something protective towear," says Francois Nicolas, a spokesman for Bering. "And the best way to dothat is to give them an airbag jacket."

Indeed, ajacket does seem to be the most logical solution. Unlike car and truck drivers,who are tethered to their seats, motorcyclists are essentially projectiles,free from the confinement and safety of an enclosed vehicle interior. That'swhy a study conducted by the European Assn. of Motorcycle Manufacturersconcluded that the risk of being killed in a motorcycle accident is 20 timeshigher than the risk in a passenger car.

Bering'snew jacket isn't the first to try to deal with those dangers, but it is thefirst to apply wireless technology to the problem. It's also the first to allowthe bike itself to decide whether it's time to fire the bag.

"We thinkthe best way to identify an accident is to let the vehicle make the decision,"Nicolas says.

Building onExperience
To be sure, others have also developed airbag jackets, but havemade them work by fastening a cable between the jacket and the bike. As aresult, those jackets actually use the airborne motorcyclist as a means to helpdetermine whether a crash is imminent.

Incontrast, Bering's airbag jacket calls for a team effort involving both thebike and the jacket. To make its decision on whether to activate the airbag,the product uses two key parameters: impact and loss of control. Working withengineers from U.S.-based FreescaleSemiconductor, a major automotive supplier, Bering developed specializedmodules to help detect a crash or a slide. A six-channel crash module, attachedto the fork of the bike, uses a pairof two-axis accelerometers and a pair of single-axisaccelerometers to look for deceleration in three axes (the devices are usedin pairs for redundancy). When the accelerometers sense impact, they sendanalog signals that are processed by an 8-bitFreescale microcontroller on board the module. The module then sends thedigitized data across a CAN databus to a separate interface module on thebike's steering bar. There, a 16-bitmicrocontroller processes the data yet again, using the firing algorithm todetermine whether the airbag needs to be activated. If it decides to fire, thenthe interface module uses an RF link to "talk" to the jacket.

Freescale,which has worked on airbags since the inception of the technology two decadesago, says that the crash sensor is the same one used by the auto industry. "Theyhad nearly the same needs as the automakers," says Matthieu Reze, automotivetechnical marketer for Freescale. "And since we had done it for automakers forso long, we knew exactly what they needed."

Still,engineers found that motorcycle airbags had their own set of challenges. Whilethe crash sensor looks for impact, a separate module under the seat watches forloss of control. Using an accelerometer and 8-bit microcontroller, this moduleanalyzes whether the motorcycle is tilting too much. Here, Bering has departedfrom traditional automotive techniques, which are more likely to look for yawthan for tilt. To do that, however, the jacket maker had to study howloss-of-control accidents occur.

"They cameup with a lot of different tests for professional bikers to do on test tracks,"Reze says. "They had to determine what (tilt) angles were acceptable for thedriver, and at what point the biker starts to lose control."

If thecycle exceeds that prescribed angle, the loss-of-control module takes note. Likethe crash module, it sends its data via a CANbus to the interface module on thesteering bar. The interface module "looks" at data from both modules, thendecides whether to fire the bag.

If it doesdecide to fire, the interface module uses a wireless transmitter. It sends asignal to an 8-bit microcontroller in the jacket, which initiates airbaginflation.

Jacketinflation is accomplished by using a switch to open a small valve on a metallichelium bottle inside the jacket. When the valve opens, the jacket's liningfills with 21 l of cold helium gas. Bering says it used helium for good reason:A pyrotechnic explosion, typically used in car airbags, would burn the wearerof the jacket. Moreover, the helium solution offers another advantage: Theairbag is filled - not just for a half-second or so, as is the case with a carairbag - but for a full six seconds, thus protecting drivers if they are thrownfrom the bike.

From the onset of the accident tothe airbag inflation, the entire process takes just 80 msec, Bering says.

Freescale engineers believe thetechnology plows new ground. "This is not the first to have an accelerometer onthe motorcycle's fork," Reze says. "But it's the first to have loss-of-controldetection and it's the first to use a wireless solution."

Testing the Market
In November, Bering rolled out the Wireless Airbag SafetySystem to motorcyclists in France, and has since sold about 500 of them at aprice of about 590 Euros apiece. Because the product is an aftermarket device,Bering has partnered with an electronics supplier, Tecno Globe, to do installation of themodules on motorcycles, and to program the bikes to work with the jackets.

"When youbuy the jacket, you buy all the modules," Reze says. "Installation is done byprofessionals. You can't do it yourself."

Beringbelieves that the jacket has arrived just in time to help Europedeal with a proliferation of small scooters and motorbikes on its streets. "In France,scooters and little bikes are everywhere," Nicolas says. "People drive thesemotorcycles without any information or even a license. We think the best thingwe can do is give them some protection."

For now,the technology is available only in France. The airbags in the jacketscan be used multiple times before replacement is necessary, Nicolas says. Twojackets can be purchased per bike to allow for passengers.

Nicolassays that Bering has talked with motorcycle manufacturers about installing and sellingthe technology on newly manufactured bikes. "We've discussed the possibilitywith them," Nicolas says. "Kawasaki was the first to take notice, but we stilldon't know how it would work."

In themeantime, Bering and many motorcycle manufacturers will undoubtedly be watchingto see how the public receives the new technology. "We'll do it in France and seehow it works here," Nicolas says. "If it goes well, then we hope to do it forexport."