Segway sales, Electric braking.

[Eric Udell <airmon@yahoo.com>]

Hi all, 
   I thought we might get a kick out of this: The
three segways for sale on Ebay ( money to charity, I
think...) drew a pretty good price. 

Quote from news.com:
" Auctions for three of the devices closed on
Amazon.com on Thursday night at $100,600, $104,100
and, after several last-minute bids, $160,000. "

Apparently all the bids are confirmed as authentic. 
Here's the link to the story:
http://news.com.com/2100-1017-871142.html

Also, with the ongoing discussion about electric
emergency  braking and primary braking, I thought the
list might like to know that the new Mercedes SL500
brake system - A computer operated brake system that
is entirely electically operated, with only a manual
backup on the front wheels. Here's an excerpt from the
review:


Begin Quote from Car and Driver Magazine:

Braking the Mold 
This new SL introduces the most significant wrinkle to
stoppers since the advent of antilock brakes: computer
operated brakes that take control of the calipers in a
way no human could emulate without four brake pedals
and the feet to work them. 

The underhood heart of the Sensotronic Brake Control
(SBC) system is a large aluminum valve block fitted
with an electric motor for maintaining 2000 to 2300
psi of fluid pressure in an adjacent hydraulic
accumulator. When you hoof the brake pedal -an
electronic sensor with a spring-loaded plunger to
mimic brake resistance but not the annoying ABS
push-back - the computer flutters the
solenoid-operated valves inside the block, releasing
pressure from the accumulator to the otherwise
conventional steel lines heading out to the calipers. 

The computer thus has ultimate command over the
pressure each caliper receives (a redundant master
cylinder provides pressure to the front calipers in
case of power failure) and uses its position of
responsibility to provide some extra capability. For
example, the system varies the brake pressure not only
fore and aft but also from side to side, applying
increased pressure on the laden outside wheels in a
turn while relaxing the inside calipers to prevent
lockup. The computer also monitors for sudden releases
of the accelerator, in which case it assumes a panic
situation is brewing and pumps up pressure while
snuggling the pads against the rotors to prepare for a
hard stop. In the rain, the system will imperceptibly
pulse the brakes every few minutes to keep the pads
dry, and over time it will learn your driving style
and tailor the brake response.
 
Considering it's the first shot at virtual brakes,
Mercedes and supplier Bosch got it mostly right. Tip
into the pedal as lightly as you can, and the initial
engagement is undetectable. Whack the pedal hard, and
the car freezes in 155 feet from 70 mph, or 10 feet
shorter than a Ferrari 360 Modena Fl (C/D, September
2000). Do it six times rapidly, and the distance grows
by just nine feet, still better than the Modena's
best. The SL's brakes also accept stomps in mid-apex
without relying on ABS or squirreling the car into
oversteer. 

The system's opaqueness increases during prolonged
mid-effort applications, such as when rolling up to a
stop sign. The pedal acquires supersensitivity,
adjusting the pressure out of proportion with small
pedal movements. Suddenly, it feels as if the car is
lurching ahead when all you meant to do was ease the
pressure slightly to stop on the appropriate dime.
Release the pedal from a dead stop, and the calipers
of our test car sometimes responded with an audible
"clunk." With this wrinkle, Mercedes still has a
little ironing to do. 
- Aaron Robinson - Car and Driver

End Quote

I know this: I love my ABS, my Probe GT leaves you
hanging in the belts when you stomp on the brake
pedal. This looks like an improvement, though not
likely to filter down to my level for quite a while.
To my mind, a backup on the front wheels seems like
enough, since they do most of the braking. 

Thoughts?

Eric Udell
airmon@yahoo.com



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