Editor's Note: The original Kawasaki Moto-GP teardown (Inside Kawasaki's Moto-GP racing bike) gave an overall view of what the bike is all about. In this follow-up piece, specially written as part of the TechOnline/EETimes Under the Hood Supplement, we dive into more details, particularly with respect to the underlying electronics and their use. Enjoy!
Unlike the Prius we tore down earlier this year, there will be no hands-on teardown of this machine: the Kawasaki Ninja ZX-RR MotoGP race motorcycle.
MotoGP is the Formula One of the two-wheel racing world, and the cost of these prototype motorcycles is thought to run into the millions of dollars. Efforts in GP are focused first on a winning performance for the marque--Kawasaki or otherwise--with a secondary objective of developing technology for the always-advancing production motorcycles available on a showroom floor. So, for now, we'll take as deep a look inside this dream machine as we can, without destroying it.
I was able to spend some time with Danilo Casonato, head engineer for the team. The setting for our discussion was the July 2007 Laguna Seca MotoGP race, where I had the pleasure of gazing at GP hardware up close while learning about the electronics inside these uniquely powerful motorcycles. Good stuff, indeed.
(Click on image to enlarge)
At 148 kg (325 pounds) and 200-plus horsepower, GP bikes are stunningly fast. As a point of reference, the current 800cc GP machines create about twice the horsepower of the 1.5-liter Prius gas engine (see the Prius teardown at www.techonline.com/underthehood/199100168,) in a package weighing just 11 percent of the car. Closer to the breed, MotoGP bikes have a power/weight ratio about three times that of my own quite-competent 600cc production Kawasaki sport bike. Beyond the fantastic mechanical engineering, custom fabrication and state-of-the-art tires in GP machines, electronics are instrumental to (horse) power management, and it is these electronics that were the focus of my discussion with Casonato.
Passing the speed gene
In some respects, the GP motorcycle class pushes the performance envelope by what might seem an absurdly small measure. Fastest Laguna Seca lap times for GP bikes were about 1 min. 22 sec, just two to three seconds quicker than the best from the modified (but still production-based) 1,000cc AMA Superbike motorcycles that raced the same weekend. Given trickle-down effects from GP, it could be argued that Superbikes wouldn't come as close without the benefits derived from prototype racing. Both race classes use electronics extensively to tune for performance and manageable power delivery, but the GP bikes remain the more potent machines, and electronics--along with overall budget--get stepped up accordingly, all to shave off even a few seconds.
On-board electronics tackle both data collection and system management. According to Casonato, "Much of the time spent optimizing happens on the dyno" where track-based data and real-time feedback are used to improve the engine control unit (ECU) and associated systems. As with any modern car, the ZX-RR's ECU maintains proper gas-air mixtures, adjusting fuel injection and controlling spark timing and profile. In the 18,000-rpm, 200-mph environment of GP, however, the ECU and associated software are brought to the limits of speed, sophistication and fine-tuning.
Of course, racing doesn't happen on a dyno, so track-specific improvements are a critical overlay to time spent in the shop. Casonato described the engineering as "one of first controlling in anticipation of the rider's actions" and second, responding to departures from controlled performance. This likely means power delivery may be adjusted up or down depending on the bike's immediate location on a specific track. Opening up available power on long straights and closing down performance for sharp, challenging corners helps cut lap times while giving the rider a safety net when the limits of tire adhesion are being stretched. If and when things get out of shape beyond that first-order control envelope, electronics are designed to take further steps to rein things in. There is GPS capability on the ZX-RR, which seems the most straightforward method to pin bike location for the purpose of control mapping.
Electronics at core of capabilities
Location sensing is just the start of the myriad electronics systems featured on the ZX-RR, from the engine control unit to the data display to remote communications. The ZX-RR ECU comes from Magneti Marelli (www.magnetimarelli.com) of Italy with its Marvel 4, designed specifically for racing. The Marvel 4 contains two 40 MIPS RISC microprocessors and an 80-MFLOP DSP along with two FPGAs. The RISC processors are joined to 512 Kbytes of nonvolatile flash memory and 32 Kbytes of RAM. (The DSP has a similar amount of flash but 512 Kbytes of RAM.) A 128-Mbyte data logger in the Marvel 4 can gather data from up to 512 channels at a maximum of 1,000 Hz. For interface, the Marvel 4 plays host to an Ethernet port used for download/upload and the bikes are constantly being plugged in to grab recorded data and remap the engine trackside. The ZX-RR's CAN bus is also implemented in the Marvel 4; much like in any vehicle, CAN provides interface to the ZX-RR's cockpit display unit among the many other data-sharing boxes onboard.
There also appears to be a second, separate, data logging box from the German outfit 2D Systems (www.2d-datarecording.com). It's not certain what the relative roles of recording in both 2D and Magnetti Marelli units might be but extensive data gathering is clearly the point of emphasis.
2D Systems also supplies the ZX-RR's LCD graphics display system, a monochrome panel delivering all system information to the rider. Analog gauges and dials are gone, with only an array of seven discrete LED shift-point indicators joining the "glass cockpit." In keeping with much of the bike's body work, a beautifully fabricated carbon-fiber case surrounds the LCD screen assembly.
For timing, the right side of the ZX-RR carries a small transponder from Netherlands-based AMB Identification and Timing (www.amb-it.com). The device is a seemingly standard piece of hardware for all MotoGP bikes, used to capture the exact time stamp of a specific motorcycle as it crosses the finish line or any other read points around the track.
Telemetry of data collected while racing is permitted, but two-way communication with rider or engine is not: MotoGP rules permit the ECU and associated systems to "speak" but not "listen," precluding remote manipulation during a race. The rider is the only dynamic control element allowed aboard; an array of buttons and other inputs quite visible on the ZX-RR are surely used by riders to make real-time tweaks to systems' behavior. Though it was not possible to get beneath the hood of the telemetry setup, plenty of real-time data is relayed, and the Marvel 4 ECU features an Arcnet interface (a 10 Mbit/s protocol similar to Ethernet) for a wireless telemetry link possibly running in the 433-MHz or 902-to-908-MHz band. Cameras are allowed aboard the motorcycles, probably as much for race audience entertainment as for engineering purposes.
A chopper disk visible on the front wheel serves to measure front wheel speed by metering the pulse train generated from the chopper's slots. While not used for an antilock brake system, the unit may serve a role for wheelie control by detecting discontinuities and imbalances in front- and rear-wheel speeds. Unlike the front wheel, a "slipper clutch" absorbs some of the back-torque of downshifts, limiting one source of rear-wheel spin mechanically. There almost certainly is electronic detection of real-wheel traction loss during acceleration that is used in the calculus of electronic engine management.
Accelerometers and lean angle sensors are "in development" (and probably all onboard as well), but Casonato said that "their use as a control input is hampered by a tendency for acquired data to be quite noisy." Noise here is not electrical disturbances, but rather the gyrating readings from sensors working in an environment where wobbles, surges and slips of the bike are somewhat de rigueur.
Casonato didn't go into detail on what is monitored, but other sensors for oxygen, temperatures, voltages, pressures and suspension travel are among the many likely suspects. A probe visible through an opening of the ZX-RR fairing, and on at least the left-most pipe, is almost certainly the Lambda oxygen sensor, used to sense lean and rich conditions from the spent exhaust. With reaction times measured in milliseconds, the Lambda probe forms a critical aspect of the control loop needed to adjust fuel-air mixture and modify ignition profiles. Other cables exiting the rear wheel cowling suggest yet more monitoring of the back tire, whether for speed, tire temperature, or both. Naturally, all this listening and looking in on system activity gets complex; Casonato said that "to keep wiring harnesses manageable, analog signal multiplexing is used" within the total array of about 30 sensors on board.
Efficiency still critical
Optimal power delivery and controlled riding are key end goals for the ECU and its numerous inputs, but fuel mileage is also important. Since there are no pit stops, riders and machines must make the 21 liters of allowed gas last a full race. Accordingly, fuel economy is carefully managed. If you can't make the last lap around the track, any lead earlier in the race is useless, and Casonato was quick to highlight the superior gas mileage of GP bikes over their larger-displacement Superbike cousins.
Throttle control is "half-rider, half 'fly-by-wire,'" according to Casonato. As with many aspects of the bike design, Kawasaki is understandably secretive about details on the link between rider throttle input and actual engine manipulation. A rubber-damped potentiometer monitors throttle position, but throttle cables are clearly present in the ZX-RR. Perhaps the cables directly control a portion of the throttle-body response but electronics fine-tune (or supplement) ultimate air delivery to the engine's intake ports.
Given the money involved and the desire to gain an edge, engineering secrets are a reality here. No photographs of the many computer screens were allowed. Clearly, software, performance data and data analysis are a huge part of the search for a competitive edge.
All the careful data forensics join with quick-thinking adjustments in this high-pressure environment, and the race for engineers and technicians happens in a well-equipped (and carpeted!) paddock along pit row. Kawasaki's GP garage had no shortage of wirelessly connected computer systems, communications radios and flat-panel screens for staying in touch with one another.
According to Theo Lockwood, engine development engineer for Kawasaki's Superbike team, engineering efforts occurred in an environment where the rider, rather than the machine, still largely determines the outcome. Additionally, the designers ultimately were there to manage (but not necessarily design) systems whose purpose is to instill rider confidence.
Man vs. electronics?
Despite the engineering excellence, the migration of electronics into GP (or Superbike) racing is not without controversy. Teams want to win, but sometimes racers just want to race, and electronics can blunt the rider's ragged-edge skills. The other side of the debate is that electronics make for a safer, more-controlled contest that is ultimately faster. Sliding, smoking tires may provide a better show, but they rarely lead to a faster race. While there have been calls for less-intrusive technologies and even outright bans on traction control, it is winning that matters; until enforceable rule changes mandate a dramatic shift, the electronics incursion into GP racing may be difficult to undo.
David Carey is president of Portelligent. The Austin, Texas, company produces teardown reports and related industry research on wireless, mobile and personal electronics (www.teardown.com).
