Safety computer systems vehicles

The increase of number, complexity and interaction of electric and electronic systems in a vehicle, bears growing challenges for development activities in the automotive domain. Besides the decreasing development time, the increasing distribution of functions and their computing control system, the draft international standard for functional safety of road vehicles ISO/DIS 26262 (International Organization for Standardization / Draft International Standard 26262) requires attention. Automotive systems demand safety and reliability, which results in consideration of safety requirements with the same level of priority as the functional requirements of the system to develop [1]. 

Today, computers are widely used iu mauy safety critical systems, such as vehicle coutrol modules, medical systems aud space applicatious. With the scaling of semiconductor technologies, soft errors are becoming a new challenge for them. 

Mazda and others have been working on advanced safety vehicles with monitor screens to show rear and side views, voice-interactive navigation systems and collision avoidance technology. The Ford 24.7 concept car had a computer console in the dashboard with Internet access that is voice-activated. 

The control systems for CNG refueling systems have evolved from being only mechanically controlled to some that are completely computer controlled today. Computer control offers flexibility not possible with mechanical systems and the ability to change the control strategy of the refueling system. Computer-controlled systems can also provide functions such as accounting of the amount of fuel dispensed into vehicles and billing functions. It is also possible to incorporate safety shut-down of the system if certain conditions are present. 

At this stage of development, it is doubtful whether a flywheel incorporated in an electrical highway vehicle can replace lead acid batteries due to problems with vibration and safety, but the performance of a lead acid battery deteriorates in hot wet conditions, requires frequent maintenance and has a life expectancy of only about 4 years. The aim of US Flywheel Systems, however, is to drive a car with a flywheel system. It is reckoned that some 16 units would be required to fulfil this objective and adequate protection would have to be supplied, since, in the event of a wheel disintegrating, it would dissipate its energy into hot fluff and high speed dust. A very sophisticated computer control system is used to filament wind each wheel with a high fiber content of 86% w/w [89]. 

Also in this context a detailed analysis of the target function and the required safety measurements is necessary in order to avoid an overall generalized safeguarding. Almost all error modes could be the possible cause of failure for safety relevant effects. To safeguard the computer just like programmable l( c control (PLCs) would not be appropriate. This is why a safety concept isn t only useful in regards to the vehicle systems but also for function or system elements, which later have to be integrated in the vehicle system. 

The use of computer controlled systems on road going vehicles is growing. Leading car manufacturers are developing, and in some cases marketing, systems which influence or take control away from the driver. The safety of normal every day drivers and passengers is increasingly dependent on the reliability of such systems. 

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