Focus on Electronics
August 2002
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Bosch manages battery power
Increasing use of electric motors to power the onboard systems of a modern car makes heavy demands on 12-V batteries. One solution is to use a separate battery for some functions, but this adds weight and cost. To ease this conflict, Bosch has come up with the Electronic Battery Management (EBM) system, which it says has been developed to make optimum use of a single battery. It uses an ECU (electronic control unit) to monitor the charge in the battery and to take what it terms "appropriate action" if it deteriorates. For example, if the charge falls below a certain level, the ECU tells the engine management system to raise the idle speed for a short time so that more power is generated. At the same time, power supply to nonessential equipment such as air conditioning can be reduced or cut off to maintain power supply to high priority systems such as brakes. Bosch says the big advantage for manufacturers is that EBM provides increased flexibility in designing onboard electrical networks and allows the battery to be made smaller and lighter. The Mercedes-Benz E-Class has the system, and other models are also expected to incorporate it.
- Stuart Birch
TRW outlines driver assistance systems roadmap
 TRW second-generation Driver Assistance Systems bring together active safety systems with video and radar sensing to support the driver. Click to enlarge |
TRW Automotive has developed a Driver Assistance Systems (DAS) vision that brings together its active safety systems—for braking, steering, suspension, and vehicle control—with video and radar sensing to support the driver and ultimately deliver collision mitigation. The roadmap is set out in phases, the technology roll-out beginning with the launch of radar-enabled Adaptive Cruise Control (ACC) on a Volkswagen Group model this year. The ultimate DAS plan involves vehicles equipped with TRW-developed x-by-wire technologies programmed to assist the driver to take evasive action to avoid or minimize vehicle crashes.
According to Nick Ford, TRW Product Planning Manager, Advanced (Electronics) Control Systems, "We're developing a number of new sensor and data-fusion technologies that will make our vision a reality. Already we have firm contracts for our ACC systems on four Volkswagen Group platforms and with two major truck OEMs and are in discussion with other major manufacturers regarding our vision systems."
Future development of TRW driver assistance systems is broken into three phases: ride and handling optimization, highly reactive vehicle control, and predictive vehicle control. Ride and handling optimization involves the integration of braking and steering systems to deliver enhanced cornering. Highly reactive vehicle control moves to by-wire technologies such as steer-by-wire and electromechanical braking as well as systems controlled by sensor fusion to deliver active braking, steering, and collision avoidance. Predictive vehicle control encompasses the integration of in-car systems and sensors with environmental sensors and intelligent transportation systems (ITS) to provide enhanced driver information and create the basis for collision mitigation and avoidance.
ACC is an example of a system that will move through these development phases. The next development phase of this system, which today sends a signal to the engine and braking system to decelerate until an appropriate following distance is achieved, is known as "follow-stop," for which the ACC system is capable of following the car in front down to a standstill. The final phase, known as "stop & go," will extend capabilities to enable acceleration.
 TRW's DAS will ultimately deliver collision mitigation in the third generation. Click to enlarge |
Advanced systems will require high-quality information on obstacles and the surrounding environment. Radar and lidar are focused on the accurate determination of vehicle locations, but consider little information about the road, so TRW is developing video-based systems that can detect road characteristics through lane markings, as well as rain and light levels. Future generations will have the potential to detect signposts, pedestrians, and vehicles. Applications that could make use of this information include lane-departure warning, lane guidance, ACC, blind-spot warning, drowsy-driver monitoring, and adaptive headlights.
A lane-following system TRW is developing for passenger cars 3 to 5 years out combines video sensing with the company's steering expertise for lateral vehicle control. Like ACC, it will follow a DAS development path, including a lane-departure warning system that analyzes video and vehicle trajectory information to warn the driver of potential lane departures through audible and haptic feedback. Future capabilities could include active control of a vehicle to maintain an acceptable lane trajectory through steering intervention.
Alastair Buchanan, TRW's R&D Program Manager for DAS technology, said, "Vision-based technologies can be used to both warn the driver of unintended lane departures and to reduce the workload of the lane-keeping task. These developments use TRW's electric power steering system, which is currently in production with Fiat and Nissan, to actuate the steering. The EPS applies an additional torque that assists the driver in lane keeping. A key design feature here is the steering feel, so that the assistance feels natural rather than intrusive."
- Kevin Jost
August 2002
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