Electronic stability control

[JimD]

Sept. 14, 2006, 12:26AM

NEW RULES FOR GREATER AUTO SAFETY

Feds to require systems meant to boost control, prevent rollovers

By DAVID SHEPARDSON

The Detroit News

WASHINGTON — Federal regulators will announce today plans to require

electronic stability control in all vehicles, a move that advocates call

the single greatest vehicle safety improvement since the seat belt.

Once all vehicles are equipped with the stability systems, likely by 2012,

it's estimated they could save at least 10,000 lives and eliminate 500,000

crashes annually, while saving billions of dollars in medical, repair and

insurance costs.

Electronic stability control (ESC) helps drivers maintain control of a

vehicle, especially on wet or icy roads, when they would otherwise veer

off the pavement or out of their lane.

Stability control also prevents up to 80 percent of rollovers in sport

utility vehicles. The higher center of gravity of SUVs makes them more

prone to tip over.

The University of Michigan Transportation Research Institute said ESC

reduces the odds of fatal rollovers by 73 percent in SUVs and 40 percent

in passenger cars, comparing it to a "guardian angel sitting on the

shoulder of the driver."

Using computer sensors that automatically activate brakes to make course

corrections, ESC works invisibly. The system prevents accidents from ever

happening, safety advocates and automotive industry officials say.

"Lots of drivers have no idea that it just saved their life or prevented a

terrible accident," said Bill Kozrya, president and CEO of Troy,

Mich.-based Continental Automotive Systems, which makes more than 40

percent of all stability control systems.

In July, National Highway Traffic Safety Administration chief Nicole Nason

told Congress that electronic stability control would save 10,600 lives a

year when fully implemented.

"This proven technology senses when a driver may lose control and

automatically stabilizes the vehicle," Nason told a House committee.

The king of safety remains the safety belt, introduced by Ford in 1955.

The NHTSA says safety belts save at least 12,000 lives and $50 billion in

medical care, lost productivity and other injury-related costs.

Two years of testing

The NHTSA will outline its new regulation today after two years of testing

on 50 vehicles. The agency will give automakers and others time to comment

and seek changes.

Congress gave NHTSA until 2009 to issue a final regulation.

Because of the lengthy planning in automotive product cycles, NHTSA

typically gives carmakers three years to implement a new regulation once

it's finalized. It could take until 2012 to see full compliance.

"We will need time to ensure that nothing in this proposed rule would

inhibit our members to keep adding this life-saving technology to more and

more vehicles," said Gloria Bergquist, vice president at the Alliance of

Automotive Manufacturers.

No industry standard

The industry supports the technology despite its costs. Providing the

system on every vehicle will cost about $200 per vehicle, or about $3

billion a year for the auto industry.

However, automakers use different names for the feature, sometimes

confusing consumers. Many drivers who have the system aren't sure if they

have it or how it works.

General Motors, which has promised to make the system available on all

models by 2010, calls its system StabiliTrak. The feature is also known as

Electronic Stability Program and Active Handling.

The proposed rules will outline what will qualify as ESC and other

technical requirements.

Joan Claybrook, president of the consumer advocacy group Public Citizen,

said suppliers of the technology have begun using consumer education

campaigns and lobbying federal officials to create demand for it.

The Washington Post contributed to this report.

[JimD]

Computers That Help You Handle Skids Like a Pro - New York Times

February 18, 2007

Technology

Computers That Help You Handle Skids Like a Pro

By JIM McCRAW

ROUNDING up the teenagers and heading to a snow-covered parking lot for driving

lessons has been a winter tradition for generations.

A wide-open expanse of slippery pavement gives neophytes a chance to learn skid

control under a parent’s watchful eye — though many teenagers surely do it on

their own — providing not only a course in crash avoidance, but a howling good

time, too. In a matter of hours, a new driver could learn the importance of a

light touch on the brakes and steering, and what to do when a spin seems

imminent.

But the spread of computer-driven features like antilock brakes and electronic

stability control may have relegated such excursions to family lore. And the

role of computers in driving safety, already well established in brake and

accelerator controls, continues to grow and to take on more responsibility —

even correcting the steering of a hamfisted driver.

The benefits of electronic stability controls are so widely acknowledged that

the National Highway Transportation Safety Administration in September proposed

new rules that would make the systems mandatory on new vehicles in 2011. The

added cost is estimated at $111 for a vehicle already equipped with antilock

brakes.

The agency estimates that universal use of stability control would prevent as

many as 10,000 deaths each year, many of them in rollover crashes of sport

utilities. Nearly 30 percent of all 2006 models were equipped with stability

control and more than half of all new S.U.V. models include the systems as

standard equipment.

The N.H.T.S.A. proposal is under review by the White House Office of Management

and Budget. Rather than wait for the rules to be finished, General Motors is

installing electronic stability systems in most of its vehicles sooner.

“General Motors is well ahead of N.H.T.S.A.’s planned rollout of stability

control,” Mike Rizzo, a lead engineer for chassis controls at G.M., said. “The

majority of our products will have it as standard by 2008, and all but our very

low-volume products by 2010.”

G.M., which introduced its first stability controls a decade ago on the Cadillac

Seville, has continued to refine the systems; this fall, a third-generation

release called StabiliTrak 3 will make its debut on the 2008 Cadillac STS luxury

sedan.

The new version goes beyond the engine and brake controls typical of stability

systems, adding a feature G.M. calls active front steering. When the rear wheels

lose traction, it can turn the front wheels into the skid — exactly as a trained

driver would — to help prevent a loss of control.

The STS is not the first car to be equipped with an active steering system. BMW

introduced the feature in the 2004 5 Series and has since made it available on

the X5 sport wagon, the 3 Series and the 6 Series.

G.M.’s first-generation StabiliTrak operated only on the front (driving) wheels.

StabiliTrak 2, a four-wheel system, arrived on the 1998 Cadillac DTS, STS and

Eldorado as well as Indianapolis 500 Pace Car versions of the Chevrolet

Corvette.

StabiliTrak, like other stability controls, makes use of the mechanical parts

that operate the antilock brakes and traction control. The system also uses a

network of sensors to continuously monitor the vehicle’s motion and the driver’s

actions, measuring cornering forces, gas pedal movement, brake pedal pressure

and how many degrees the steering wheel has been turned, among other parameters.

Using data gathered from these sensors, the system acts to keep the vehicle from

understeering, the condition when front wheels lose traction, or oversteering,

which occurs when grip at the rear wheels is lost. Mr. Rizzo said the system

intervened very quickly to reduce vehicle speed, first by closing the throttle

and then by applying the brakes at a single corner of the car to coax the

vehicle back onto the driver’s intended path.

For example, the driver of a car entering a left curve too quickly may find the

rear end slipping to the outside of the curve as the cornering forces exceed the

available tire grip. A device in the stability control called a yaw sensor

detects the difference between the car’s actual direction of travel and the

driver’s intended course and applies the right front brake through the antilock

system.

The operation of an electronic stability control system is similar to piloting a

canoe, Mr. Rizzo said.

“If you’re paddling a canoe from the rear and want to point the bow to the left,

you put your oar in the water on the left,” he said. “The bow turns left,

rotating around the oar. That’s essentially what we are doing.”

The steering corrections performed by StabiliTrak 3 are carried out by the

active front steering hardware — a gearbox and a powerful electric motor

positioned on the shaft that connects the steering wheel with the car’s

rack-and-pinion assembly.

Mr. Rizzo said that active steering could add or subtract steering as needed to

avoid a loss of stability; considerable effort went into making sure that the

driver would feel nothing unusual at the steering wheel while this correction

took place.

The engineer responsible for calibrating the STS system, Chris Kinser, said that

if an experienced driver steered in the direction of the skid to counteract it,

the system could quickly add more steering; if a driver reacts slowly or not at

all to the skid, the system takes over and turns the steering wheel the

necessary amount.

A further benefit of the system is its ability to change the steering ratio —

the relationship of how much turning of the steering wheel changes the angle of

the front wheels — in a range from 12:1 to 20:1. In practice, that means a car

equipped with StabiliTrak 3 will require fewer turns of the steering wheel in

low-speed maneuvers like parking, yet at highway speeds will have a ratio slow

enough to keep the vehicle from darting across the lane when the driver

twitches.

Mr. Kinser says that to keep the system feeling natural and normal to the

driver, it is limited to adding the equivalent of 60 degrees of steering-wheel

rotation in emergency maneuvers, and only about 20 degrees in steady-state

driving. Movement of the front wheels is limited to four degrees.