Et puis non, je vais vous faire travailler l'anglais (et le mien aussi)
Un des articles les plus intéressant que j'ai lu sur le sujet pour le moment!
Bonne lecture...
It's fast machines all over again. A previous interview with EFI engineer
Danilo Casonato of Kawasaki's MotoGP Engineering Team touched on how electronics get woven into that team's entries for the top tier of motorcycle racing. At this year's MotoGP
race at Mazda Laguna Seca Raceway, in Monterey, Calif., I went back for more, primed by my earlier introduction to a high-technology, one-off
race-hardware world characterized by big-time speed, sound and an underlying air of secrecy.
To better grasp the whole of MotoGP electronics, a repeat visit in Kawasaki's pit-lane paddock was accompanied by a session each with Yamaha's GP-team data engineer, Suzuki's GP crew chief along with a co-founder of Germany's 2D Systems, a key sensor and electronics box supplier to those three factory teams.
The almost absurd power-to-weight ratio of MotoGP bikes has led teams to pursue sophisticated machine-control intervention to help keep riders on two wheels, and one of my primary questions revolved around autonomy in bike control during the
race. Since the pit is prohibited from making in-
race changes,
race-time modifications--such as ignition timing and throttle-fuel mapping--must be made by the rider and onboard systems that determine if, when, how and even where performance adjustments are implemented.
[Vous devez être inscrit et connecté pour voir cette image]But less clear is how these decisions are driven by real-time sensory inputs. Does the bike position on-track enter into the control equation and, if so, how is it done reliably? How is the rider's throttle application modulated with electronic "ride-by-wire" on the way to air/fuel delivery? Drilling deeper gets one to the question of sensor arrays used to drive all the control functions. What's being measured, what data do these sensors provide, and how do teams use and collect data? Figuring prominently are datalogging, data analysis, and decision-making based on both. In an ocean of data, how do you swim in the right direction to improve performance?
I put forth lots of questions and, in the end, got quite a few answers, thanks to the time each team graciously extended to highlight the electronics engineering behind its individual efforts.
Getting revved upKawasaki's Ian Wheeler arranged a discussion with Andrea Dosoli, EFI technician onsite at Laguna Seca this year. As a former crew chief and current motocross rider, Andrea's focus on electronics systems is balanced with the perspective of the entire system and the rider responsible for making it all work on the track.
This year, Kawasaki's main focus is a new, more capable engine control unit (ECU). Working more closely with long-time partner Magneti Marelli of Italy, Kawasaki sees a deeper development role as strategic imperative for a competitive control system. Similarly, post-action data analysis is placing greater demands on a rich data set and software analysis to bring home a clearer picture of the bike in action.
Kawasaki's electronics control systemBut mechatronics and control loops can still fall short when it comes to a human-driven activity. Despite moves by other teams to a full ride-by-wire system (where throttle application is electronically translated into acceleration of the engine) Kawasaki maintains--at least for now-- their "half-and-half" system. A physical cable from the rider throttle input controls half of the four-cylinder throttle bodies but electronic systems pick up the rest. In essence, Dosoli acknowledged a team "philosophy of feel," which keeps the rider more fully connected to the machine.
To my surprise, Dosoli indicated that real-time control based on the location of the motorcycle on the circuit had not yet fully made the transition from test track to racetrack. The system is definitely in the later stages of development and its full-time use on the
race bike is fairly imminent, though Dosoli refused to be drawn on whether elements of the real-time control system are in use on the team's current MotoGP machines. What Dosoli would confirm is that GPS is the way forward for reliable position-pinning on track, as inertial navigation systems remains plagued by noise and signal ambiguities.
To be sure, data collection for later analysis relies on GPS location-stamping, but heat-of-the-moment decisions are made by learning which sensors tell the story with enough accuracy to manage the motorcycle's response to rider inputs and bike behaviors.
[Vous devez être inscrit et connecté pour voir cette image]Putting the power downA two-year-old mandate reducing MotoGP engine displacement has given engineers a bit less raw power to manage. Smooth power delivery is key; the measures the ECU takes to level the peaks and valleys of engine output become more tractable when the engines are a bit smaller. Dosoli indicated that sensors for acceleration, bank angle, front-wheel and GPS-speeds, along with front-wheel suspension stroke, are the more important parameters for real-time control in Kawasaki's MotoGP machine.
Controlled wheel spin can be a racer's tool for riding fast, but too much can result in a dramatic "high-side" which bucks the rider off the bike in dangerous fashion. By comparing front- and rear-wheel speeds with GPS-speed and engine rev-up, the bike can "see" when a muted response to throttle input is needed from the traction control system (TCS) in order to maintain grip. In fact, racers coming from production-class racing to MotoGP experience the impact of unprecedented tire grip, TCS, ride-by-wire, and rich sensor-based control. Several have commented on how much sooner they can get on the gas in a turn.
So, what does Kawasaki's electronics control system look like? Of course the team will never fully say, but Dosoli acknowledged an array of about 50 sensors on board, all communicating over multiplexed ECU/datalogger feeds with CAN busses. Thirty analog sensors join with four temperature monitors, exhaust oxygen level (lambda), and a host of other digital sensors. ECU control and datalogging can get to be a busy affair. For example, the "quick shifter" strain gauge on the foot shift lever--used for timing the ignition cut-out during clutchless gear changes--benefits from KHz sample rates to get it right.
Mounds of data also demand an Ethernet interface on the
race bike to download information and upload new control programs in short order. But not all the work happens at the frenzied pace of the racetrack. Post-practice and qualifying hours are spent with engineers and technicians poring over much deeper and granular acquired data to improve setup and systems for the
race, and the racing season.
Yamaha Tech3 tuningThe varying approaches to racing electronics within the GP campaign were highlighted in my visit with Andrew Griffith, data engineer for one of Yamaha's two factory MotoGP teams. Griffith began with a Motorsport Engineering degree from Swansea University in Wales, eventually distributing his graduate research project up and down the pit lane to land his job in MotoGP.
Griffith said there are teams using "in-house" ECUs, such as Honda and Ducati, but like Kawasaki, Yamaha Tech3 is using Magneti Marelli for engine control and 2D Systems for datalogging and sensory systems.
While sharing similarities with Kawasaki's approach, Griffith's team has gone to a full throttle-by-wire system. Physical cables from throttle to engine bay still exist--to provide the rider a conventional feel--but Yamaha has chosen to fully interject stepper-motor throttle body control between the rider's physical input and engine response.
[Vous devez être inscrit et connecté pour voir cette image]Yamaha too employs a vast array of sensors on the motorcycle, along with accelerometers and gyros that track bike movement. GPS is on-board for data-tagging, but Griffith echoed Dosoli's comment about the tenuous nature of GPS as a reliable real-time control positioning input. To the larger point, Griffith spoke of the need for control-system simplicity because overly complex approaches breed their own set of safety issues.
Though "turned off for qualifying sessions," TCS and wheelie control are areas of focus for Yamaha during the
race. The many other sensors onboard may play a role in TCS but "front- and rear-wheel speed differences are the key parameters you have to have to make it work" said Griffith. Since riders sometimes need to get a little loose, Griffith indicated it's more about controlling a window of allowable spin versus demanding full traction full-time.
To this end, Griffith and his team seem to appreciate the need for a rider to feel in control of the bike. When a racer's inputs sometimes contradict the data-implied optimums for settings and setup, an approach that delivers comfort and confidence over sterile computer-driven "optimization" is what's best.
Like its competitors, Yamaha can't stand still in development however. The team is employing a "new philosophy this year," but Griffith didn't reveal much more due to competitive issues. When asked about the development of a position-based, real-time, autonomous control system, the only response was a grin and the suggestion that this "was one possible direction" for the team. The silence spoke loudly enough to suggest such an approach is certainly on their minds if not on their motorcycles.
Suzuki lightningA few pit stalls away, I visited with Tom O'Kane, an engineer who also targeted training in motorsports. O'Kane, like Griffith and Dosoli, was fortunate enough to "know what he wanted to do", going on to become crew chief for Suzuki's rider Chris Vermeulean under team technical director Shinichi Sahara, who set up the interview. As a riding enthusiast himself--Ducati twins being a favorite--O'Kane also shares a holistic view of man and machine when approaching his work.
Like the Kawsaki and Yamaha models, the Suzuki bikes are fully loaded with GPS, 3-axis accelerometers, 3-axis gyros and "30 plus" sensors over three CAN busses, all used for a mix of quick setup optimization and later, more detailed data analysis. 2D Systems is a repeat vendor to Suzuki for dashboard electronics, system sensors, and datalogging, while Mitsubishi supplies the ECU technology.
O'Kane was more direct on the question of location-based engine management. Knowledge of on-track position and the details of track characteristics can, in theory, allow for better autonomous control approaches and O'Kane went so far as to say that transponders around the track could be combined with time-distance interpolation to figure out bike location. However, he also said 6-axis monitoring (3-axis gyro + 3-axis accelerometers) "describes how things are moving, but is not used for inertial positioning" due to off-axis noise and drift in the sensors. Discussions of control system implementation and data sampling/filtering in use at Suzuki soon moved into the realm of "don't print that" but suffice it to say that things are getting quite scientific in places.
[Vous devez être inscrit et connecté pour voir cette image]In the realm of traction control, O'Kane's comments mirrored the others', citing the "lower power/easier to correct" notion for 800-cc
race bikes versus previous 990-cc machines. Still, the ECU counters fluctuations of the engine power curve to deliver linear and predictable response for maximum pilot confidence, all while leaving enough room for riders to get some rear wheel slip when they want it.
Despite all the technology being thrown at winning, O'Kane--like Griffith at Yamaha--said sometimes the data doesn't show the differences and they have to go by rider feel/input. Similar to Kawasaki, Suzuki also employs a "half-and-half" ride-by-wire system to retain a conventional throttle feel and give the rider a strong sense of connection to the machine. There is a constant pull between "feeling" and "measurement" and back-room sharing of knowledge between Suzuki's otherwise separate MotoGP and Superbike teams is one of several methods used to try and sort it all out.
2D Systems sensing sensibilityMy last stop was with Dirk Debus, German co-founder of 2D Systems, major supplier of sensory, cockpit and data-logging systems to the MotoGP world. A club racer and computer science major from Hertz alma mater Universität Karlsruhe, Debus built a tinkerer's monitoring effort on his own racebikes into a business with co-founder Rainer Diebold.
As the man behind much of the sensory gear, Debus spoke of the monitoring challenges in an environment where 30-G levels of vibration noise risk overshadowing the 1-1.5-G signals of interest.
Open-systems approach
Debus reflected upon the need for an open-systems approach and a company emphasis to avoid a "monoculture of components" which are too specialized and too critical. In both sensors and cockpit display systems, 2D has to work with ECUs from all players--Magneti Marelli, Honda and Mitsubishi, among others--and flexibility in interface design is key to serving multiple teams.
A signal-to-noise ratio of 1:20 requires great care in component selection, along with clever software. When asked about whose accelerometers and gyros work best, Debus wouldn't name names, but indicated a reliance on German parts in his GP-sensor boxes.
[Vous devez être inscrit et connecté pour voir cette image]I was amused when Debus answered the question of "Toughest thing to deal with?" with a quick reply: "The Riders!" As an engineer Debus can understandably struggle with the vagaries of human feedback but, as a rider himself, he can perhaps uniquely and legitimately get away with saying such things.
It was surprising to see a relatively small enterprise have such a presence in the well-heeled world of MotoGP. How did 2D Systems succeed in a land of giants? Again a quick response by Debus summed up the company's perceived edge nicely: "Knowledge, experience and passion!"
Good assets for almost any effort, really.
To the finish lineMy thanks to the folks at Kawasaki, Suzuki, 2D Systems and Yamaha, who shared time to peel back some of the mystery of electronics technology in MotoGP. A nod also to Neil Spalding, author of the definitive book on MotoGP technology development, for help in formulating the right questions. If you want more technical detail, buy the gentleman's book--you can't go wrong. Finally, thanks to Dave Clegg, my motorcycle-riding (and engineering) colleague who helped with picture-taking and talking points. Collectively, these folks helped paint a crisper picture of what's going on with electronics engineering in the pinnacle of motorcycle racing. Rest assured, there are plenty of secrets unspoken in the massive technology push for MotoGP--maybe next year.