The Potential of Optical Sensors for Future Restraints Systems

摘要

State of the art automotive restraint systems have reached a very high level of occupant protection. Vehicle construction, belt and airbag systems are the most important life savers in this respect. The vehicle installation rate of restraint systems covers almost 100%. With the electronic sensing systems that are currently installed in the vehicles it is only possible to react on the physical impact in the moment the impact takes place. The already started introduction of reversible restraint devices shows that it becomes necessary to get information about a critical situation or even a possible impact much earlier than it is possible with a conventional sensing approach. Object detection, classification and conditioning of the reversible restraint devices consumes much more time than it is available in an ordinary impact. The full potential of reversible restraint devices can only be achieved if they are activated before the actual impact occurs. An another challenge is the pending regulation on pedestrian safety, where we will also be required to activate protection systems at a very early stage. To fulfil the timing requirements, sensors are needed that provide information about objects in close proximity in the driving direction of the vehicle. Sensors are required that are able to determine if a collision is unavoidable, to provide additional information about the impact speed, direction and size of the target object. Optical sensor systems have shown a very high potential to fulfil this requirement. They are able to detect standing objects, compared to systems that are base on other technologies. Optical sensors have a high resolution and can be built small enough to even fit in mini sized vehicles. Additional functions that are also based on optical effects, e.g. rain sensor, light and temperature sensing etc. can easily be integrated and therefore optical sensors have a high potential to become a real multifunctional low cost measurement system.