Brake by wire coming soon

[bigpoppa]

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Brake by wire is coming to motorcycles - RevZilla

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"Brake by wire means that braking is actuated electronically, not hydro-mechanically via the fluid displaced by your lever and pedal. Hand or foot motion still activates your brakes as usual, except your braking inputs become signals sent to the brake control computer in a brake by wire system, which uses the signals to deliver the right amount of braking, at the right wheel(s), at the right time. That entire process should happen faster than normal braking with even more power and control. The computer also uses wheel-speed sensors to determine if additional braking measures are needed, like ABS for a panic stop. Brake by wire is designed for integration with existing rider safety systems and features.

Not convinced of brake by wire’s speed? Formula 1 cars have all adopted the system at this point, along with performance street cars like the new Corvette. It’s also gaining popularity with electric vehicles, such as Audi’s E-Tron, for reasons I’ll get into later."

 

[TwistedKestrel]

I am all for the current best available available implementation of ABS (IMU-controlled), but I'm not sold on this. The loss of direct mechanical feedback seems like a high price to pay, manufacturers go to great lengths today to make sure that it is engineered in. It may be a non-issue as motorcycles are generally resistant to dramatic increases in complexity, especially when it adds mass. Examples - how long it took for IAC to become common in EFI, variable valve timing is still pretty rare, the number of bikes that STILL are sold with damper rod forks. And it did take motorcycle ABS a long ass time to get where it is now.

 

[bigpoppa]

I am all for the current best available available implementation of ABS (IMU-controlled), but I'm not sold on this. The loss of direct mechanical feedback seems like a high price to pay, manufacturers go to great lengths today to make sure that it is engineered in. It may be a non-issue as motorcycles are generally resistant to dramatic increases in complexity, especially when it adds mass. Examples - how long it took for IAC to become common in EFI, variable valve timing is still pretty rare, the number of bikes that STILL are sold with damper rod forks. And it did take motorcycle ABS a long ass time to get where it is now.

from the article "In the "wet" brake by wire systems we’ll likely see on motorcycles, the master cylinders and brake lines aren’t simply replaced with sensors and wires. Hydraulic master cylinders remain in place to preserve “normal” braking feel, but instead of providing feedback from actual pad-to-disc contact, the master cylinder is connected to a brake resistance simulator to give the feel you’d expect from standard brakes. The simulator can be tuned to provide a particular feel or sharpness."

 

[GreyGhost]

from the article "In the "wet" brake by wire systems we’ll likely see on motorcycles, the master cylinders and brake lines aren’t simply replaced with sensors and wires. Hydraulic master cylinders remain in place to preserve “normal” braking feel, but instead of providing feedback from actual pad-to-disc contact, the master cylinder is connected to a brake resistance simulator to give the feel you’d expect from standard brakes. The simulator can be tuned to provide a particular feel or sharpness."

I am sure given enough time, the artificial feedback could be awesome (the computer could amplify the feeling to make it easier to determine what is going on). For the first few generations, barf. Power steering has been around for how long? Electric power steering not as long but even worse feel. Manual steering still beats all of the powered systems for feel.

Edit:

I still miss rear drum brakes on bikes. The drum was never perfectly round so you could feel the speed of the rear wheel. Almost telepathic control. Obviously had some weight/power drawbacks so not a good front wheel solution but I still like it better for rear brakes.

 

[Michael0124]

I remember when I was first introduced to electric power steering, I could definitely tell it was "artificial". 10 years later I bought a car and didn't realize it had electric steering until I looked under the hood, it felt so natural.

They made advances with that I'm sure eventually they will with this.

 

[Brian P]

Thread/article title is a little bit misleading. There must be (required by motor vehicle safety standards) a mechanical/hydraulic backup in the event that power assistance (by whatever method it is achieved) fails.

It's true that things are moving towards having a master cylinder actuate fluid against a normally-open valve in the ABS controller with a pressure sensor and with the actual brake pressure applied under normal operation by an electrically-driven pump - but the system has to actively hold that valve closed. In a power-down situation, the valve opens and allows normal manually-actuated brake actuation. The Corvette is like this.

In NO way in the foreseeable future, is this going to eliminate a hydraulic master cylinder and hydraulically-actuated brake calipers, nor will it eliminate the hydraulic path between them.

 

[TwistedKestrel]

Thread/article title is a little bit misleading. There must be (required by motor vehicle safety standards) a mechanical/hydraulic backup in the event that power assistance (by whatever method it is achieved) fails.

It's true that things are moving towards having a master cylinder actuate fluid against a normally-open valve in the ABS controller with a pressure sensor and with the actual brake pressure applied under normal operation by an electrically-driven pump - but the system has to actively hold that valve closed. In a power-down situation, the valve opens and allows normal manually-actuated brake actuation. The Corvette is like this.

In NO way in the foreseeable future, is this going to eliminate a hydraulic master cylinder and hydraulically-actuated brake calipers, nor will it eliminate the hydraulic path between them.

Sure, but the article itself did say that. And it references F1 brake by wire, which is just about the mildest implementation possible

 

[Trials]

I expect it will become standard equipment,
in an era where electric powered self driving vehicles are standard equipment and everything rides on rails that power and control the vehicles every movement

 

[oomis]

Wait, is this different from the "servo assisted braking" that BMW had on their GS line years back? If so, BMW's experience was ... problematic at best. There was a huge cheer when they dropped it and went back to traditional setups.

 

[Priller]

ABS already has control over the brakes in many bikes (witness the frustration of previous-gen CBR1000RR riders when the ABS would send them straight on at the track), so this isn't much different from the switch to throttle-by-wire with ECU's controlling the fuelling. That said...

There's an interesting comment further down from the article from someone who says they've been involved in similar development for cars (TurboLover). He says the big appeal there is it allows combining the master cylinder, brake booster and ABS module into a single component, saving space under the hood. As motorcycles don't have brake boosters, he thinks they'll be less interest from manufacturers. He also says he's skeptical they would have a separate unit for front and rear braking, which would require deletion of the rear brake.

The other factor against this in motorcycles is that a big benefit in cars is faster application of hard braking than the driver can provide. That's actually a problem in motorcycles, as the small front contact patch needs progressive loading through the forks before it can really work. And squeezing a lever takes much less time than moving a foot from the gas to the brake, then pressing through a long stroke. ABS already deals with the more common problem of a sudden brake grab locking the front, so the benefits would be minimal. The obvious exception to this would be something like the new Multistrada that has radar and therefore could independently apply brakes in case of rider distraction...

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