2010 brake system

[fuzzy1]

Originally Posted by bwilson4web

... I'm uploading the spreadsheet with the data. Feel free to join in data analysis. ...

About what speed did you hit the speed bump? I'm trying to estimate 'extra braking distance' caused by this, and compare it to both braking distance at this level of decel, and to hard braking.

My attempt to integrate the acceleration data to get a speed profile isn't scaled correctly. And of course there is no zero speed reference.

I hope more of these events can be recorded, to put some bounds on decel losses and dropout times.

[bwilson4web]

Hi,

Feel free to check my work:

Originally Posted by fuzzy1

About what speed did you hit the speed bump? I'm trying to estimate 'extra braking distance' caused by this, and compare it to both braking distance at this level of decel, and to hard braking.

My attempt to integrate the acceleration data to get a speed profile isn't scaled correctly. And of course there is no zero speed reference.
. . .

Near as I can tell:

• ~8 m/s - initial contact with speed bump
• ~7.6 m/s, ~655 ms duration - end speed bump event
• 7.6 m/s, ~700 ms duration - no speed delay, ~5.32 m
• resume deceleration

I used the stop at the gate to find the integration constant for the zero point:


I don't think the reduced braking from the speed bump can be counted against the reduced stopping distance. However, the 700-800 ms. of effectively no stopping force directly relates to extended stopping.

I have to admire the irony of a "speed bump" leading to an extended stopping distance.

Bob Wilson

[bwilson4web]

Originally Posted by austingreen

. . .
Is there a way to use my iphone as the acclerometer?

OWCH! I wished I'd thought of it! Good idea!

I'll check the iTunes store to see what is available for my iPod Touch:

• Accelerometer Data ($3) - just downloaded to begin testing, looks promising!

Bob Wilson

[adrianblack]

Originally Posted by bwilson4web

OWCH! I wished I'd thought of it! Good idea!

I'll check the iTunes store to see what is available for my iPod Touch:

• Accelerometer Data ($3) - just downloaded to begin testing

Bob Wilson

OMG -- too simple! LOL

Looks like the Pro version $8 might be the one to get ... 100hz sample rate, and it stores the data on the iPhone/iTouch as a CSV which you can grab via Wifi.

[bwilson4web]

Originally Posted by adrianblack

OMG -- too simple! LOL

Looks like the Pro version $8 might be the one to get ... 100hz sample rate, and it stores the data on the iPhone/iTouch as a CSV which you can grab via Wifi.

I agree. The $3 version works but is limited in the number of samples and if you start another application, it looks like the data is lost. Still:

Timestamp,AccelX,AccelY,AccelZ
0,0.126785,-0.670151,-0.742599
0.100172,0.144897,-0.633926,-0.742599
0.200286,0.144897,-0.670151,-0.778824
0.300247,0.126785,-0.670151,-0.742599
0.400363,0.126785,-0.688263,-0.742599
0.500524,0.144897,-0.652039,-0.724487
0.600505,0.144897,-0.706375,-0.742599
0.700671,0.126785,-0.670151,-0.688263
0.800808,0.163010,-0.688263,-0.742599
0.90085,0.163010,-0.688263,-0.706375
1.00079,0.144897,-0.706375,-0.760712
. . .

So I've got some really nice, dedicated acclerometers with high resolution, 160-320 samples per second. But while one is out, I'll be able to use the iPod Touch as a second. With three accelerometers located at three locations, I should be able to generate all six metrics ... NEAT!

I can use the less expensive accelerometer connected to axles and use the iPod for body motion. . . . hummm

Bob Wilson

[hitechboy]

Wow! Bob what a work! I am your fans from now on!

[adrianblack]

Originally Posted by bwilson4web

I can use the less expensive accelerometer connected to axles and use the iPod for body motion. . . . hummm

Bob Wilson

What's cool is if you buy the app and you have an iPod and a Touch, you can have it on both. It seems possible to buy 8gb 2nd gen iPod touches on Ebay for about $130-ish ...

Oh, the app "Axeleron" seems to log to files as well, and it samples at up to 100hz and is free. (At the moment, at least.) It also logs your location and you can email the CSV to yourself.

[Rhino]

Purely technical question.

Has anyone tried the new Prius with the new software vs. the old 2010 Prius? Is there a mileage different (i.e., mpg difference)? Or is the fix so minimal that mileage is unaffected.

[barbaram]

Having had a 2006 Prius, AND as a locomotive engineer who has to deal with slip/slide systems that do not always respond as expected, this problem has not caused me too much trouble. My training demands that I always be in control of my vehicle. I guess that has spilled over to my driving style. I've felt the brakes slip a bit under bumpy conditions. Common sense tells me to drive with more caution.
Guess I'm not a typical driver.....

[adrianblack]

Originally Posted by adrianblack

What's cool is if you buy the app and you have an iPod and a Touch, you can have it on both. It seems possible to buy 8gb 2nd gen iPod touches on Ebay for about $130-ish ...

Oh, the app "Axeleron" seems to log to files as well, and it samples at up to 100hz and is free. (At the moment, at least.) It also logs your location and you can email the CSV to yourself.

This app works, but the timestamp data has a resolution of 1 second -- and it seems to drop samples, at least at 100hz. Too bad, since it seems to work otherwise.