RE: [A/S]Technology and sway control

["David & Bret" <dtbw_1999@xxxxxxxxx>]

Years ago Holiday Rambler had a BIG problem with their trailers going
into a no-warning, uncontrolled sway and then flipping on their sides
(even with anti-sway hitches such as the Reese Dual Cam).  The problem
was such an issue that they finally added active sway control (they
called it ASCS, Automatic Sway Control System), which solved the
problem.  I assume that Holiday solved the underlying stability problem
over time as they dropped the active anti-sway system, but it was still
in use in the middle 80s and some of these rigs are still going strong
on the nation's highways.

I would bet it will only be a matter of time before we see the return of
active, brake-based, anti-sway systems.  The whole idea is simple, just
detect sway (yaw), apply trailer brakes gently, then release trailer
brakes once sway is eliminated. (ie the same thing you can do manually
with the brake controller).  All of the technology is very mature.
Existing controllers such as the Prodigy already use the same principal,
just monitoring the deceleration along longitudinal axis of travel
rather than yaw. To ensure that normal cornering was not mistaken for
sway, a sensor at the hitch and another at the rear would be compared
and the delta between them would indicate the rate of yaw which could
feed the brake controlling circuits.  It would even be possible to have
the yaw signal modulated on the same wire that operates the brakes (no
extra wiring), so that the smarts could co-reside and use the brake
controlling circuits contained in a modern microprocessed brake
controller such as the BrakeSmart from MasterBrake or the Prodigy.
(MasterBrake is already doign this with their BrakeSmart unit when it is
coupled with their ElecDraulic hydraulic brake system.)

This approach would make towing a lot safer for the masses and the added
cost of the anti-sway components over the base microprocessed brake
controller would be less than even friction sway controls. I think this
would be a most welcome improvement and installing the sensors and
multiplexing hardware on the trailer would be simple enough for after
market installation.  The distance from the hitch ball to each sensor is
all that would have to be entered into the controller for it to compute
sway accurately.

BTW, this technology (active handling) is now either standard or
optional on virtually every higher end sports car in production.  I have
it on my 2000 vette.  It works like magic and has saved my butt on more
than one occasion.  Granted it is a bit more sophisticated in operation
than what I envision for anti-sway, but the principals and hardware are
the same.

david