How The Robot ASIMO Helped Build Honda's MotoGP Electronics Package
The major leap forward which Honda's MotoGP bike has taken in the past two seasons has come in two distinct areas, the chassis and the electronics. Much of the work of sorting out the RC212V's chassis was done during the 2010 season, when the factory tried out five different chassis variations and several different swingarms, before getting the bike right early in the 2011 season. Parallel to the chassis, Honda spent two years improving their MotoGP bike's electronics, after poaching two of Yamaha's key staff to work on HRC's electronics package. The resulting machine, in the hands of Casey Stoner, proved unbeatable throughout the 2011 season.
A photo posted on Twitter by Augusto Moreno de Carlos, editor of the Spanish magazine Motociclismo, provides an insight into how the development of technology can take interesting paths. The photo shows how ASIMO, the robot Honda has built as a technology demonstrator and R&D project, provided some of the crucial technology for HRC's MotoGP machine. The multidimensional inclinometer used by the RC212V to detect the attitude of the bike is a direct development of the system used by ASIMO to monitor the robot's balance as it walks and runs. The inclinometer, consisting of a collection of gyroscopes and accelerometers, provides information on how the position of the bike is changing: Is the bike banked over in a turn? Is the bike wheelying under power, or pitched forward on the brakes? How hard are the braking forces? How fast is the bike being tipped into the corner?
On the basis of this information, the electronics package on the RC212V can change the engine power characteristics to help the riders control the bike better. By sensing that the bike is braking hard - especially by combining brake pressure information with data from the inclinometer about the attitude the bike is in - the electronics can regulate the amount of engine braking to apply. By sensing that the bike is leaned hard over, power delivery can be made smoother to prevent the rear tire from breaking traction too harshly. By sensing that the bike is being stood up hard on corner exit, power delivery can be ramped up more quickly, allowing the bike to accelerate harder as the rider gets the bike onto the fat part of the tire.
Although entirely logical when viewed in hindsight, it is fascinating that the electronics required to monitor a MotoGP bike should be derived from a walking robot. Bipedal motion - walking on two legs - is a massively complex undertaking, requiring managing a constantly shifting center of gravity, as the technical manual Honda issued about ASIMO shows in some detail. Though the speeds involved are much lower - ASIMO's top speed is 9 km/h while running, a little over a brisk walk - the complexities and the required speed of data processing are broadly similar; the fact that the two wheels of a motorcycle are relatively rigidly fixed together mean that transitioning between physical positions is gradual. The fact that the human legs and torso which ASIMO is copying have multiple degrees of freedom in their movements means that the number of variables involved are greater, and change at a much greater rate.
While the achievements of Honda in building the RC212V's electronics management package are many, their package does not by any means give them an insuperable advantage. The electronics used by both Yamaha and Ducati are equally complex, with Yamaha revealing at Valencia that the electronics package uses predictive algorithms to adjust levels of control to accommodate tire wear and fuel consumption patterns as the laps tick off. The Yamaha's electronics package constantly monitors the response of the tire and bike against the behavior calculated using data from practice sessions. Electronics strategies are constantly changed to adapt to the feedback coming from the bike, and new strategies calculated for the following laps based on that feedback. Yamaha, like Honda, uses gyros and accelerometers to detect bike behavior and adapt to it: two years ago, Yamaha switched their anti-wheelie strategy from data coming from the suspension travel sensors to gyros registering bike pitch. That meant that the wheelie was being detected before the front wheel left the ground and the front forks were fully extended, and power could be cut earlier, but by less.
What both the data from Honda and Yamaha show is that limiting electronics on MotoGP bikes - as Carmelo Ezpeleta is set on doing for 2013 onwards - is not simple. Data on bike attitude from gyros and accelerometers has become increasingly important, as demonstrated by the marginal effect that banning the use of GPS data has had this season. Arguably, banning data from inclinometer packages would have a much greater impact on bike control than banning GPS ever did. With no data from accelerometers, wheelie control would be more difficult, and the factories would have to rely on supension data again. With no data from gyros, there would be limited information on how far the bike was being leaned over, making it more difficult to alter throttle response and the way that power feeds in based on the angle of the bike. More control would be handed back to the riders, and away from the electronics.
Given the freedom to program ECUs as they wish, electronics programmers would soon work their way around the problem. Though precise data on lean angle and acceleration might be missing, data collected through the data acquisition packages can be used to simulate bike attitude quite closely. Using just the data from the brakes, engine revs, throttle position, selected gear and gear ratios, the position of the bike can be plotted remarkably accurately. Using that data, programmers can take a very good guess at the attitude of the bike, and adjust throttle response and engine mapping as required. It won't be as accurate as using inclinometers, but it will be more than good enough.
Even physically enforcing a ban on inclinometer data could be very difficult. Anyone carrying a modern smartphone is carrying an accelerometer and a gyroscope, as the ability to switch display modes as you tilt and turn the phone will show. The size of the sensors required is already tiny: one commonly used triple-axis digital gyroscopic sensor measures just 4mm x 4mm x 0.9mm. Cost is also not an issue: mounted on a printed circuit board, the sensor can be purchased for under $50. As sensors get smaller, they become easier to hide, leaving the only option for controlling their use monitoring the data coming into the ECU, or imposing a spec ECU on the series and restricting the parameters available to the programmers.
Controlling the growth of electronics in motorcycle racing is not easy, and given the technology crossovers between racing and other areas - as shown by the use of technology from a walking robot on a MotoGP bike - certainly goes against the wishes of the factories. Finding a compromise which allows the factories to perform useful R&D while allowing spectacular racing is going to be hard. But given the dire nature of the racing during the fuel-starved 800cc era, it is also going to be absolutely necessary.