Control device of the type mentioned in the introduction are used, for example, but by no means exclusively, in motor vehicles for actuating many different systems and functions of the motor vehicle. Numerous systems and functions are operated electrically and controlled electronically in modern motor vehicles. This applies both to complex mechanical assembly units of the powertrain, for example, for vehicle transmissions, and to simpler functions such as electric seat adjustment, windshield wiper drives, for various electronic devices in the vehicle and the like.
However, the electrical or electronic actuation of such systems, which makes do without mechanical connection, entails that there may sometimes not be an unambiguous assignment between the position of an actuating element and the state of the system that can be controlled by means of the actuating element, for example, a vehicle transmission. In other words, this means that the desired state of the system being controlled, for example, of the vehicle transmission, which state is selected with the actuating element, does not agree with the actual switching state of the system or the transmission.
Such a divergence between the states of a technical system and the control elements thereof may have various causes.
For example, erroneous or non-functioning recognition or detection of the position of the control element may occur, with the consequence that the gear, preselected, for example, by the driver with the control element, was not recognized by the system and the corresponding control command was not therefore sent to the transmission. Erroneous or non-functioning transmission of the control command between the control element and the system being controlled therewith is, for example, just as conceivable. However, the situation that technical systems, for example, vehicle transmissions, automatically adapt their operating or switching state to changed general conditions and change them without direct action on the part of the driver also occurs increasingly frequently in modern motor vehicles with the increasingly interconnected, complex technical systems used there. Thus, it is not uncommon, for example, that a vehicle transmission controlled by wire will automatically assume the shift position P (parking brake) when the engine is shut off and after the ignition key has been removed.
Another example, used only for illustration, is the comparatively simple case in which the system being controlled is the windshield washer/wiper unit of a vehicle. It is already known in this case as well that the windshield wiper will be turned on automatically, for example, in case of heavy fog or when precipitation begins, based on corresponding sensor signals. However, this means that the operating state of the windshield wiper will no longer possibly agree with the switching state of the control element for the windshield wiper.
The control element thus incorrectly signals, due to its unchanged position in the off position, that the windshield wiper is turned off, whereas it is actually in operation because of the automatic activation. Even if the actual operating position may be easily recognizable in case of the windshield wiper, at least the problem still remains that the actuating element is already in the off position when manual intervention with the automatic system of the windshield wiper is possibly desirable, i.e., to turn off the windshield wiper.
Resilient actuating elements, which automatically always return into a neutral middle position after the actuation, are used sometimes in the state of the art in case of such incompatibilities, or extremely complicated switching logics and corresponding displays, which have to display the instantaneous operating state of the system being controlled and shall also display the directions of motion of the actuating element necessary or possible for the control, are used at times.
The document EP 1 045 172 B1, in which it appears especially already from the figures that control concepts of such a design and form for technical systems in the motor vehicle cannot certainly be described as being intuitive or easy to understand, may be mentioned as an example hereof. Aside from the lack of control comfort of a man-machine interaction of such a design, such complicated control concepts can obviously also lead to undesired consequences in terms of the concentration of the driver on the actual driving action, and thus to problems with driving safety.
It is readily apparent that the cases are only examples of the more general problems of the interaction between man and machine in the case of electronically controlled systems, in which the control elements are in connection with the system to be controlled only via electric or electronic signals rather than via mechanical linkages or shafts.