The function of the Human Machine Interface (HMI) is, on the one hand, the intuitive control of various vehicle functions. At the same time, vehicle control elements also convey an image statement. The higher the vehicle class, the more important ease of use and haptic control unit feedback become. When operating a switch or rotary knob, several factors can be used to determine how sophisticated it is. Surface properties, feeling of operation and noises generated during use are indicators of the customer's perceived quality feeling. OEMs want this value in harmony with cost-effective and modular solutions they can use for different device versions and that enable them to differentiate themselves from brand-specific ones. There is also a focus on reliability. Control elements must at least last as long as the vehicle's service life. All these requirements can be met with Preh's intelligent control system, which separates the haptic design from the physical function. This approach is based on three particularities. The use of a so-called Hall sensor in conjunction with a ball bearing and latch spring enables the cogging steps to be clearly determined and ensures an excellent tactile feeling. The latter is also supported by a handy two-component rotary knob. Flexible plastic properties are retained via Preh's PVD technology. With this technology, an approximately 300 nm thin metal surface can be applied, which, in contrast to a metal coating, prevents the plastic from becoming brittle.
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