Operating device for controlling windscreen wiper system involves evaluating rain sensor signal profile to detect smears from maximum positive, negative gradients in measurement interval

摘要

The method involves a rain sensor in the windscreen wiping field outputting a signal to an evaluation unit depending on moisture on the screen. The evaluation unit generates a wiper system control signal. The sensor signal time profile is evaluated to detect smears from the maximum positive and negative gradients of the sensor signal during a measurement interval extending from before to after the period of wiping over the rain sensor surface.