Gravity, Inertia, G's, Torque, Fjr,

[radman]

Most ABS systems work by comparing the speed of the wheels, using the toothed reluctor wheels. The Feej system adds chassis speed into the equation. Since the Yamanual doesn't break down the ECU/ABS control unit, one has to assume there is an decelerometer built in for this function. But in any case, from what I can see, front/rear wheel speed differential AND chassis deceleration are all taken into account. Sophisticated, by neccessity. Automotive systems work somewhat differently, and due to wheelbase and much more weight (any idea how hard it is to lock up fronts on a late model car on good pavement these days?) Rears lock readily-fronts not so easily. Now, most of my knowledge of automotive systems is somewhat dated, so this is not gospel by any means. Automotive may very well use chassis dynamics for ECM info now.

 

[radman]

One of the key things I learned at racin' school was this; a tire has a potential 100% of traction available for any given manuever. Subtract for every input. If braking takes away 50%, you have 50% for turning, say. In panic situations, or high speed for that matter, keeping this in mind can help immensly. Turn but don't brake: brake but don't turn. Accelerate and turn and the result is predictable-the famous shitty. Adding either to the other detracts X amount from the force available for either. ABS helps in this situation by returning some traction to the equation, some force is available for turning in this instance. One is still better off not forcing the system to try to compensate. Did I make any sense here?

 

[twowheelnut]

Most ABS systems work by comparing the speed of the wheels, using the toothed reluctor wheels.  The Feej system adds chassis speed into the equation.  Since the Yamanual doesn't break down the ECU/ABS control unit, one has to assume there is an decelerometer built in for this function.  But in any case, from what I can see, front/rear wheel speed differential AND chassis deceleration are all taken into account.  Sophisticated, by neccessity.  Automotive systems work somewhat differently, and due to wheelbase and much more weight (any idea how hard it is to lock up fronts on a late model car on good pavement these days?)  Rears lock readily-fronts not so easily.  Now, most of my knowledge of automotive systems is somewhat dated, so this is not gospel by any means.  Automotive may very well use chassis dynamics for ECM info now.

See? Is so hard not to use the word 'gay' when speaking to people?

 

[radman]

Most ABS systems work by comparing the speed of the wheels, using the toothed reluctor wheels. The Feej system adds chassis speed into the equation. Since the Yamanual doesn't break down the ECU/ABS control unit, one has to assume there is an decelerometer built in for this function. But in any case, from what I can see, front/rear wheel speed differential AND chassis deceleration are all taken into account. Sophisticated, by neccessity. Automotive systems work somewhat differently, and due to wheelbase and much more weight (any idea how hard it is to lock up fronts on a late model car on good pavement these days?) Rears lock readily-fronts not so easily. Now, most of my knowledge of automotive systems is somewhat dated, so this is not gospel by any means. Automotive may very well use chassis dynamics for ECM info now.  Ya felchin' fudge packin nut likkin queer eye and teeth and arm and shit sonsobitches.

Whatever do ya mean TDub? Not a "gay" in there anywheres.

 

[twowheelnut]

Cute. God bless the Edit button. Oh, wait. I shouldn't use the 'G' word, should I? Might upset the atheists among us...

 

[Thug]

IONBEAM

Ah..A volts and Booze man eh?

 

[Thug]

IONBEAM

Ah..A volts and Booze man eh?

 

[Penforhire]

Instantaneous peak G's don't matter much. It sure won't get you around a traction circle and it won't even help that much at auto-x. My car is rated right around 1.0 G steady. Care to put your 1.4 peak G against that? Didn't think so.

Maybe I should have said the "average" deceleration of our bikes is limited to around 1 G. Or do you pick a bone with that too? Kind of a no-brainer assessment based on stopping distance, G-Tech need not apply.

 

[ionbeam]

Ah..A volts and Booze man eh?

I decided not to mix sex and guns, next thing you know I would be sent out for social neutering like radman :haha:

As to the volts, nothing over 5 million. The difference between my volts and booze is when sampling them, one causes you to wake up feeling like shit and the other causes you not to wake up at all :rip:

Or do you pick a bone with that too?

Just reporting what the G-Tech reports. The topic starter was asking about Gs so that was the way I answered. Stopping distance is what really matters and that measured around 124 to 126. There was additional capability left but I ran out of courage. I will let the people that are younger and heal faster find out what the ultimate braking capacity of a street ridden FJR is :scare2:

Alan

 

[Pappy]

Hey ion,

Looks like you're the guy to answer a question...

ABS system in cars have 4 sensors for vehicle speed (each wheel) which provides a good source as in most conditions it's unlikely that all four wheels would be locked at once.

On bikes, it's very likely that in a panic stop the rear wheel will lock and possibly the front also. How does motorcycle-based (i.e. two-wheel vehicle speed sensing) deal with the loss of vehocle speed to determine slip-angle.

In other words: What the fook does the cornputer does when both dem wheels stop turn'in?

 

[ionbeam]

  What the fook does the cornputer does when both dem wheels stop turn'in?

Yamaha's stinkin' manual doesn't say much that is helpful. I was surprised to see it mentioned slip angle though! Refer to what radman said at the top of page 2, he pretty much has it nailed. The FSM does mention measuring chassis deceleration but doesn't say anything else about it, even in the troubleshooting guide so it has to be something magic within the ABS ECU (electronic control unit). The FSM *does say* that the ECU looks at the rate of wheel deceleration and from that calculates if the braking results in wheel speed deceleration rates that fall outside a 'normal range' and that triggers the ABS.

In automotive ABS systems there are 1 channel, 3 channel and 4 channel systems. One channel systems only monitor the front wheels as a pair. Three channel systems monitor the front wheels individually and the rear wheels as a pair. Four channel systems monitor all 4 wheels independently. Feejer has a 2 channel system, both wheel are monitored independently of each other and ABS gets actuated independently.

I have some insight into cager ABS because a friend of mine owns the consulting engineering firm that GM hired to develop GM's ABS program. This very smart guy liked to talk shop and I kept my mouth shut and listened. On occasion my brain melted and ran out my ears. My friend and I were a lucky few civilians allowed to take the full MA State Police EVOC program (Emergency Vehicle Operations Course, it was absolutely the tits) and they devoted a large chunk of time discussing ABS in terms of vehicle dynamics and accident scene reconstruction

In all those words there must be some kind of an answer for you Pappy :lol:

Alan

 

[Pappy]

I figured it must be a rate-of-change system. That's the only control law that I think would work consistantly on a two-wheel vehicle.

The ECU must be fairly advanced to monitor the system at a high-enough sampling-rate to be effective. I presume it also controls the FI and ignition also?

 

[ionbeam]

I presume it also controls the FI and ignition also?

There are 2 ECUs on an ABS bike. The standard issue FI/Spark/Meter ECU for the mundane and a dedicated ABS ECU. Within the ABS ECU there is a continuing software program loop -- a monitoring loop running all the time. The main program completes a loop every 8 mS (in 8 thousands of a second) within this program loop, while riding, it runs a self diagnosis; receives all signals; controls operation as required and depressurize/pressurizes the braking system as needed. [end 8 mS] Initiate next loop. [end 8 mS later] repeat, repeat.... In terms of electronics 8 mS is an eternity. Note that 'receives all signals' includes watching and counting pulses from both wheels. At 158 mph how many times per second are the wheels turning and how many teeth are there on the ABS wheel? That's a shit load of counting!!! Not to mention as the ECU measures the pulses it has to perform a 'timing difference' calculation, check a table to see if there is an out of normal reading and decide what to do - for both wheels, every pulse, all the time.

Good Wife notes that her S10 PU is a one channel system that only works on the REAR pair of wheels. Details, details. Who's idea was it to teach women to read anyway?

Alan

 

[RadioHowie]

Ah, a lover of fish lips, eh?  Which reminds me...
"Fish heads, fish heads

Oohy goohy fish heads

Fish heads, fish heads

Eat 'em up, yum."

If'n yer gonna sing it, sing it right!

Fish Heads

 

[Bounce]

So, if you are on sand and can't achieve 1 G deceleration why does ABS engage?

Because ABS has sensors to check each tire for "lock up". Even if your G's are lower than some max setting, a tire that stops spinning will trigger the ABS. That is it's main function. Beyond that, thar be magic 'n' sea serpents!

 

[twowheelnut]

Ah, a lover of fish lips, eh?  Which reminds me...
"Fish heads, fish heads

Oohy goohy fish heads

Fish heads, fish heads

Eat 'em up, yum."

If'n yer gonna sing it, sing it right!

Fish Heads

First, that's the way I taught my little sister how to sing it. Second, it's been so long since I heard the song that I forgot about the rolly polly part! Third, how the hell did you link me directly to an audio clip? That, I'd really like to know...

 

[RadioHowie]

Ah, a lover of fish lips, eh?  Which reminds me...
"Fish heads, fish heads

Oohy goohy fish heads

Fish heads, fish heads

Eat 'em up, yum."

If'n yer gonna sing it, sing it right!

Fish Heads

First, that's the way I taught my little sister how to sing it. Second, it's been so long since I heard the song that I forgot about the rolly polly part! Third, how the hell did you link me directly to an audio clip? That, I'd really like to know...

If I told ya...I'd have to kill ya. :assasin:

But seriously, I put the audio up on one of my radio stations' websites in WMA format, and the link is a WMX link, which is simply a streaming audio pointer to an audio file resident on the server.

Here's the script for the WMX...simple HTML:

<ASX version = "3.0">

<Entry>

<Ref href = "https://www.halllakeland.com/rex/fish.wma" />

</Entry>

</ASX>

and of course the wma has to be where the wmx points to.

Pretty slick, huh? Works with videos, too. So, if you ever click a link that opens up streaming audio or video, without downloading said audio or video, you can save the WMX (audio) or WVX (video) file, open the file up in an editor like notepad, and see where the actual audio or video file is hosted and download the actual file itself. Great way to figure out where the actual file is, so you can save it to your system.