One of the most important aims of the automotive industry is to provide the best possible protection for drivers and passengers. In addition to this, greater emphasis is also being laid on how best to protect pedestrians in the event of accidents. In its CAPS (Combined Active and Passive Safety) programme, global supplier of automotive and industrial technology Bosch is developing new functions which help achieve these goals.
By linking existing active and passive automobile safety systems and extending these by adding systems for monitoring and evaluating a vehicle's environment, Bosch is creating the foundation for new safety functions. These assist the driver in critical situations and help to avoid accidents, or at least reduce their severity.
The company is networking the active and passive safety systems with the driver assistance systems to create the modular safety system CAPS (Combined Active and Passive Safety). This provides a basis on which new functions for even greater accident protection can be implemented. The first CAPS functions, such as the Predictive Brake Assistant and the Predictive Collision Warning, can already be found in series-produced cars. "As the next step, Bosch will also integrate the vehicle communication into CAPS," says Herbert Hemming, executive vice-president for sales in the Chassis Systems Control Division. "In that way we will increase safety on the roads even further."
It can happen quickly: reaching spontaneously for a dropped CD, or an excited discussion with the passenger, and the car driver has already briefly lost his overview of the traffic. The Bosch safety and driver assistance systems are already supporting the driver in this kind of situation, helping to avoid accidents or to make them less serious. Bosch developers want to increase this high level of safety even further with CAPS. The new functions help to prevent or to reduce the effect of potential collisions at the front, side and rear of the vehicle, and to minimise the chance of the vehicle rolling over. This brings the vision of accident-free driving one step closer.
CAPS GETS WORKING
The first CAPS functions, created through the interaction of the radar sensor of the Adaptive Cruise Control (ACC) and the Electronic Stability Program (ESP) are already in series production. These predictive safety systems build on one another: if the radar sensor detects a critical traffic situation, the Predictive Brake Assist brings the brake shoes closer to the brake discs (unnoticeably for the driver), and prepares the brake assistant for the possibility of emergency braking.
If the driver then does in fact have to brake sharply, full braking is achieved more quickly. This can crucially reduce the braking distance. The next stage of development is already in series production in the recently launched Audi Q7: Predictive Collision Warning. If the driver fails to react, and the distance from the car in front becomes even shorter, the driver is then actively warned by means, for instance, of a short burst of the brakes. The third stage of development, called Predictive Emergency Braking, will in future even be able to initiate emergency braking automatically.
FUTURE FUNCTIONS
In the event of an accident, the airbag control unit at present determines the intensity and direction of an impact, and triggers the restraining equipment such as airbags or belt tighteners as required. By networking the airbag control unit with other systems and sensors in the vehicle, CAPS will further protect occupants.
As an example, about 20 percent of all fatal accidents in the world involve the vehicle rolling over. Advanced Rollover Sensing, an improved rollover sensing system, optimises the protective benefits of the restraint systems when the vehicle rolls over, by including the ESP data about the state of the vehicle in the airbag control unit's calculations. This allows the best times to trigger the belt tighteners, side and head airbags and the roll bar to be determined even earlier and more reliably. The first applications will go into series production as early as 2006.
Integrating the ESP data into the control of the restraint systems can also improve safety in the event of a side collision. It is not just as the consequence of an accident that the belt tightener can be triggered. The CAPS Prefire function activates reversible belt tighteners when driving dynamics become critical. The vehicle occupants can therefore be optimally positioned in case an accident does indeed happen.
The data from navigation systems will in the future bring a further extension to the possibilities of CAPS. Information about the car's current position and the layout of the roads can, for instance, be used to warn the driver in advance of danger spots, eg dangerous crossings, tight curves or accident blackspots. Video sensors will also soon play a central role in CAPS; systems for lane detection are one example. The system will warn the driver if the vehicle is about to accidentally leave the lane. It will even be possible, through networking with active steering, for the vehicle then to be brought back into the lane. Other possible applications of video sensors include night vision support, traffic sign detection, the detection of other vehicles or obstacles on the road in front.
Research into accidents is an important starting point for the development of new CAPS functions. For this reason, Bosch is analyzing traffic and accident data from around the world, so that the benefits of new functions can be determined in advance on the basis of typical accident scenarios. CAPS is a modular system that can be adapted to widely varying electronic vehicle architectures. It is also possible for the CAPS functions to be distributed across different control units. The CAPS functional interfaces have been designed so that systems and control units from different suppliers can be integrated to create a total system.