An active rollover protection (ARP), is a system that recognizes impending
rollover and selectively applies
brake
A brake is a machine, mechanical device that inhibits motion by absorbing energy from a moving system. It is used for Acceleration, slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of ...
s to resist.
[http://www-nrd.nhtsa.dot.gov/pdf/esv/esv19/05-0471-O.pdf Bosch Rollover Mitigation Functions]
ARP builds on
electronic stability control
Electronic stability control (ESC), also referred to as electronic stability program (ESP) or dynamic stability control (DSC), is a computerized technology that improves a car handling, vehicle's stability by detecting and reducing loss of Tract ...
and its three
chassis control systems already on the vehicle –
anti-lock braking system
An anti-lock braking system (ABS) is a Automotive safety, safety anti-Skid (automobile), skid Brake, braking system used on aircraft and on land motor vehicle, vehicles, such as cars, motorcycles, trucks, and buses. ABS operates by preventing t ...
,
traction control and
yaw control. ARP adds another function: detection of an impending rollover. Excessive lateral force, generated by excessive speed in a turn, may result in a rollover. ARP automatically responds whenever it detects a potential rollover. ARP rapidly applies the brakes with a high burst of pressure to the appropriate wheels and sometimes decreases the engine torque
to interrupt the rollover before it occurs.
Rollovers can also occur when the vehicle is knocked into a stationary object such as a curb. In these so-called "trip events",
[Hrovat, Davorin D., Hongtei E. Tseng, and Michael G. Fodor. "Roll over stability control for an automotive vehicle having an active suspension". Ford Global Technologies, assignee. Patent 7140619. 2006.] a vehicle hit from the side but kept from moving laterally by a curb would produce a
moment about the
center of gravity sufficient to produce a rollover. To counteract this, rollover stability systems have begun to incorporate an
active suspension system in rollover protection. To accomplish this, the onboard computer uses data from the
inertial measurement unit
An inertial measurement unit (IMU) is an electronic device that measures and reports a body's specific force, angular rate, and sometimes the Orientation (geometry), orientation of the body, using a combination of accelerometers, gyroscopes, an ...
(IMU) to determine when a vehicle is in a rollover condition independent of
yaw rate and vehicle speed. When the computer determines that the vehicle is at risk of rollover, it calculates the direction of roll and activates the active suspension system. The force produced in the suspension creates a moment (
torque
In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...
) opposite to that created by the lateral force, and keeps the vehicle safe.
Other uses
The phrase is also used for active roll over bars for convertible cars, such as the Volkswagen Beetle, which can detect potential roll-over situations and automatically raises rollover bars hidden in the rear head restraints in a fraction of a second.
See also
*
Anti-roll bar
*
Crosswind stabilization
*
Gyroscope
A gyroscope (from Ancient Greek γῦρος ''gŷros'', "round" and σκοπέω ''skopéō'', "to look") is a device used for measuring or maintaining Orientation (geometry), orientation and angular velocity. It is a spinning wheel or disc in ...
*
Roll cage
*
Roll over protection structure
*
Side Impact Protection System
*
WHIPS (Whiplash Protection System)
References
External links
Continental Automotive SystemsSafelyThere – Continental Automotive Systems
{{Authority control
Vehicle safety technologies
Vehicle braking technologies