TRW develops roll-stability control system

LIVONIA, Mich. (Aug. 9, 2001) — TRW Chassis Systems has developed new technology designed to help improve the roll stability on vehicles with a high center of gravity. The company said its Active Roll Control (ARC) system can help vehicle manufacturers meet anticipated U.S. federal requirements under the TREAD Act, including the new dynamic rollover testing standard.

The technology uses hydraulic and electronic technology to reduce or eliminate the vehicle roll angle in cornering, which improves handling. This improvement to vehicle handling helps reduce rollover risk.

The ARC system combines typical steering and braking technology with additional sensors, including a lateral accelerometer, steering angle sensor and other sensors that already exist on many vehicles today. ARC also uses an actuator at one end of both the front and rear stabilizer bars.

During handling manoeuvres, the accelerometer and sensor sense the roll force created by the cornering of the vehicle. The actuators then apply an offsetting force to the end of the stabilizer bar to reduce roll angle and assist the vehicle in maintaining a stable operating condition.

These actuators are effectively inactive during normal vehicle operation to allow for a softer ride.

In straight-ahead driving, the stabilizer bar is free to move with wheel motions up to the stroke of the actuator. Since no pressure is generated in the actuators, the bar is, in effect, disconnected. In this condition, the ride of the vehicle is improved, with little or no “head toss” and better single wheel bump performance. Axle articulation also is improved for off-road use.

By combining the new ARC technology with other TRW innovations in steering and braking, TRW said it can offer higher levels of performance and cost otherwise unrealized by the individual systems.