Bosch plans to use side thrusters to stop motorcycle lowsiding
Manufacturers go to great lengths to make their motorcycles as safe as possible and usually the task is handled by electronics, such as traction control, cornering ABS and electronic suspensions. Apparently, no one had thought to employ rockets to help a bike stay upright. Until Bosch, that is.
As every rider should know, there is no such thing as a fall-free motorcycle. There are too many variables that determine the dynamic equilibrium of a moving two-wheeler, and a good chunk of them are not rider-dependent.
One of the most common mishaps a rider will sooner or later face on public roads is the lowside, which is usually the result of the front wheel losing traction. No matter how well equipped a motorcycle is in terms of safety features, there's very little an electronic sensor can do if a rider tips into a corner too fast, or brakes too much, or simply runs over something slippery mid-corner.
Most of the time and for the majority of riders, saving a lowside is a case of sheer luck and perhaps a little bit of experience; keeping the throttle open is probably the only thing that might save the day if there's enough room for the bike to regain traction.
For Bosch though, there is an alternative approach to saving a lowside, one that is currently examined under the "sliding mitigation research project" and is compared to a magic hand stepping up to save the spill. The whole idea revolves around using a well-established technology in a completely new way.
For the role of the magic hand, Bosch suggests employing side thrust to counter the bike's slip. Most modern motorcycles are already equipped with sensors that can identify when a wheel drifts sideways, so, when a certain amount is exceeded, a nozzle sprays gas in a direction that will counter the slip, keeping the bike upright and on its trajectory.
It sure sounds a lot like the principle of rocket propulsion, and in this case Bosch suggests using gas accumulators already in use in car airbags. The whole system relies on commonly applied technology, simply rearranged for a new purpose.
There are several questions that come to mind about this idea. Would it require refilling the gas canister after use? How much would this add to a bike's weight? How will it fare when the loss of traction is not the result of tire running over something slippery, but rather a rider going too fast? Could the attempt to correct the lowside result in turning it into a highside, sending the rider flying?
Although it is probably too early to deal with its practical aspects, the sliding mitigation project seems to be already well on its way and Bosch has a working prototype proving it works.
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For that purpose I imagine mounting two equal, counter-rotating reaction wheels transversely to the length of the bike. While running at the same rpm between uses the reaction wheel pair has zero total angular momentum.
When needed an ESP-like system dynamically applies braking forces to the reaction wheels to generate torques as needed for optimizing the bike's angle with respect to the road surface. The reaction wheels have to be re-energized after use in a corner.
The above system saps some energy and it experiences wear and tear (particularly of the ball bearings of the reaction wheels), so it's only active when needed.
The reaction wheels might generate an unacceptable amount of precession whenever the ESP unbalances the pair on purpose, so I think that a low-power ESP-system is appropriate or the whole idea is unworkable in practice.
I also thought of the reaction wheel idea, it's much more practical and useful idea. It could be part of a kinetic energy recovery system. The bearings should be gas (helium) film rather than ball bearings for low friction and high load capacity. Reaction wheels operate by torquing the whole plane of rotation of the wheel rather than changing the rotation rate of the wheel; this gives much higher force than just changing the rotation rate. Having two pairs of reaction wheels would allow controlling pitch (wheelie) as well as roll.