TRW Delivers Improved Vehicle Dynamic Control and Braking PerformanceJune 16, 2006
The automotive supplier integrates electrically powered steering and electronic stability control systems.
PARIS /PRNewswire-FirstCall/ -- TRW Automotive Holdings Corp. highlighted further systems integration success, demonstrating the integration of TRW's electrically powered steering (EPS) and electronic stability control (ESC) systems to enable an enhanced level of vehicle control and assist drivers across a range of driving conditions.
The integration of the braking and steering system can deliver braking performance improvements on split coefficient (mu) surfaces—such as two wheels braking on pavement and two wheels braking on ice—as well as driver support and comfort through the steering control.
Dr. Alois Seewald, global engineering director of TRW Automotive's systems integration team, explained: "The integration of two active safety systems offers significant benefits not only in terms of vehicle stability and driving safety, but also in ride comfort and total systems costs for the vehicle manufacturer."
A prime example is the steering torque control (STC) function that can help to correct situations such as oversteer in hard cornering or rapid lane-change maneuvers. STC functionality is delivered through the integration of TRW's column drive EPS and ESC systems and the creation of integration algorithms to enable the application of steering torque in oversteer and in split mu braking conditions. This is achieved without requiring additional sensors.
STC also offers oversteer control assist. In an oversteer situation, such as a rapid lane-change maneuver or hard cornering, the EPS system generates a steering torque, helping to "coach" the driver to the direction of the required steering angle correction.
The generated torque is limited to a level that enables the driver to override the intervention. The driver will feel opposing torque and can choose to bypass the intervention or allow the vehicle to take the corrective measure. These corrections help to stabilize the vehicle and minimize yaw and skidding.
Another feature of STC is enhanced split mu assist. During the split mu braking situation, the braking and steering systems work together to maximize the vehicle stability and driver confidence while the vehicle stops. The EPS system generates steering torque to encourage the driver to counter-steer and respond to vehicle yaw in a controlled fashion. As a result, higher braking pressures can be initiated on the high mu side, providing the potential to reduce stopping distance.
Seewald added: "We have developed this integrated active safety system to deliver tangible comfort and safety benefits. In addition to enhanced comfort and support to the driver through controlled steering intervention, the system improves vehicle stability with fewer ESC interventions. Moreover, the system achieves an improvement of around 8 % in split mu braking performance at 80 kilometers per hour. This is the equivalent of the average length of a vehicle, which could make a difference in real traffic situations."
Steering Torque Control can offer additional features, such as side-wind compensation, trailer-stability control, and pull-drift compensation to offset road camber. The function can be achieved through software enhancements on TRW's electrically powered steering system or with the addition of a module for hydraulic steering systems.
To see the full complement of TRW active and passive and integrated safety technologies, please visit the company's Web site.
With 2005 sales of $12.6 billion, TRW Automotive ranks among the world's leading automotive suppliers. Headquartered in Livonia, Mich., the company, through its subsidiaries, employs approximately 63,000 people in 25 countries. TRW Automotive products include integrated vehicle control and driver assist systems, braking systems, steering systems, suspension systems, occupant safety systems (seat belts and airbags), electronics, engine components, fastening systems, and aftermarket replacement parts and services.
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