Active Rollover Protection
Encyclopedia
An active rollover protection (ARP), is a system that recognizes impending rollover and selectively applies brake
s to resist.
ARP builds on Electronic Stability Control
and its three chassis
control systems already on the vehicle - Anti-lock braking system
, traction control
and yaw control. ARP adds another function: detection of an impending rollover. Excessive lateral force, generated excessive speed ia 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 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", 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
(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
) opposite to that created by the lateral force, and keeps the vehicle safe.
Brake
A brake is a mechanical device which inhibits motion. Its opposite component is a clutch. The rest of this article is dedicated to various types of vehicular brakes....
s to resist.
ARP builds on Electronic Stability Control
Electronic Stability Control
Electronic stability control is a computerized technology that may potentially improve the safety of a vehicle's stability by detecting and minimizing skids. When ESC detects loss of steering control, it automatically applies the brakes to help "steer" the vehicle where the driver intends to go...
and its three chassis
Chassis
A chassis consists of an internal framework that supports a man-made object. It is analogous to an animal's skeleton. An example of a chassis is the underpart of a motor vehicle, consisting of the frame with the wheels and machinery.- Vehicles :In the case of vehicles, the term chassis means the...
control systems already on the vehicle - Anti-lock braking system
Anti-lock braking system
An anti-lock braking system is a safety system that allows the wheels on a motor vehicle to continue interacting tractively with the road surface as directed by driver steering inputs while braking, preventing the wheels from locking up and therefore avoiding skidding.An ABS generally offers...
, traction control
Traction control system
A traction control system , also known as anti-slip regulation , is typically a secondary function of the anti-lock braking system on production motor vehicles, designed to prevent loss of traction of driven road wheels...
and yaw control. ARP adds another function: detection of an impending rollover. Excessive lateral force, generated excessive speed ia 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 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", a vehicle hit from the side but kept from moving laterally by a curb would produce a moment
Moment (physics)
In physics, the term moment can refer to many different concepts:*Moment of force is the tendency of a force to twist or rotate an object; see the article torque for details. This is an important, basic concept in engineering and physics. A moment is valued mathematically as the product of the...
about the center of gravity
Center of gravity
In physics, a center of gravity of a material body is a point that may be used for a summary description of gravitational interactions. In a uniform gravitational field, the center of mass serves as the center of gravity...
sufficient to produce a rollover. To counteract this, rollover stability systems have begun to incorporate an active suspension
Active suspension
Active or adaptive suspension is an automotive technology that controls the vertical movement of the wheels with an onboard system rather than the movement being determined entirely by the road surface...
system in rollover protection. To accomplish this, the onboard computer uses data from the Inertial Measurement Unit
Inertial measurement unit
An inertial measurement unit, or IMU, is an electronic device that measures and reports on a craft's velocity, orientation, and gravitational forces, using a combination of accelerometers and gyroscopes. IMUs are typically used to maneuver aircraft, including UAVs, among many others, and...
(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
Torque
Torque, moment or moment of force , is the tendency of a force to rotate an object about an axis, fulcrum, or pivot. Just as a force is a push or a pull, a torque can be thought of as a twist....
) opposite to that created by the lateral force, and keeps the vehicle safe.
See also
- GyroscopeGyroscopeA gyroscope is a device for measuring or maintaining orientation, based on the principles of angular momentum. In essence, a mechanical gyroscope is a spinning wheel or disk whose axle is free to take any orientation...
- Roll cageRoll cageA roll cage is a specially constructed frame built in the cab of a vehicle to protect its occupants from being injured in an accident, particularly in the event of a roll-over. Roll cages are used in nearly all purpose-built racecars, and in most cars modified for racing...
- Roll over protection structureRoll over protection structureRoll Over Protection Structure refers to operator compartment structures intended to protect equipment operators from injuries caused by vehicle overturns or rollovers.Commonly found on heavy equipment Roll Over Protection Structure (ROPS) refers to operator compartment structures (usually cabs...
- Side Impact Protection SystemSide Impact Protection SystemA Side Impact Protection System is a system of protection against injury in side collisions, developed by Volvo.SIPS was released in the Volvo 700, 900 and 850 series in 1991....
- WHIPSWHIPSWHIPS, or Whiplash Protection System, is a system of protection against automotive whiplash injuries introduced by Volvo in 1999 in the Volvo S80....
(Whiplash Protection System)