ABS and ASR for Passenger Cars -Coals and Limits 890834
Antilock Braking Systems (ABS) and Traction Control Systems (ASR) should ensure maximum stability and steerability even under extreme driving conditions. Since high performance systems additionally improve brake distance and traction within the given physical limits, every vehicle equipped with ABS and ASR offers considerably higher active safety.
ABS was introduced into the market by the Robert Bosch GmbH more than ten years ago, and more than 3 million systems have been produced by the end of 1988. Volume production of ASR began in 1987.
This paper describes several high-, medium-, and low performance concepts and compares them with regard to safety and performance. Although it seems to be nearly impossible to define a cost/benefit ratio between monetary values and safety, our purpose here is to identify further development strategies through the use of a decision matrix.
Many simplified ABS-concepts lead to major shortcomings in control performance, safety, and/or system reliability. As a result, they will ultimately have to be upgraded to meet these requirements. As an alternative, there is a potential for cost reduction of the existing high performance systems with no or little performance degradation. The comparison of both strategies will show that high performance systems will remain successful on a long term basis even though a limited market for simple two-channel-systems, for example in combination with special 4WD concepts may develop.
High performance Traction Control concepts which guarantee stability for rear wheel driven cars must adapt the drive torque with high speed and accuracy. Since the engine performance and the stability impairment by spinning wheels is comparatively limited for front wheel driven cars, there may be different optimum concept approaches depending on the drive concept. This will also be described in more detail.