Im Cockpit von Kraftfahrzeugen, nimmt die Zahl von Komfortfunktionen sowie Unterhaltungsfunktionen und damit auch die der Bedienelemente stetig zu. Zur Verringerung der Komplexität können viele einzelne derselben durch ein zentrales multifunktionales Element ersetzt werden. Zur Vermeidung von Fehlinterpretationen können hier Informationen zusätzlich visuell oder akustisch angezeigt werden. Beide Möglichkeiten stoßen schnell an ihre Grenzen, da sie den Fahrer von seiner Fahraufgabe ablenken. Als letzte Option bleibt daher die im Bericht behandelte haptische Rückmeldung mit variablen Betätigungskräften.
This investigation reveals that there is a correlation between the positioning accuracy and the perception of difference. Thus, the perception of differences increases with big differences of the torque amplitudes. However, the positioning accuracy decreases when the difference of the amplitudes gets bigger. Nevertheless, the increase of the perception quote is clearly bigger than the decrease of the positioning accuracy. A well-balanced ratio between positioning accuracy and perception quote is reached by scaling factors between 1.20 and 1.875. Furthermore the investigation reveals that a higher positioning accuracy can be reached by the use of a falling saw tooth-shaped torque function instead of a rising saw tooth-shaped one. However, the influence of the kind of the torque function on the perception of differences does not become clear. But there is a convergence of the perception quotes if the compensation of friction is reduced. The sequence of the amplitudes influences the positioning accuracy less than assumed. Just a small trend of a higher error quote can be ascertained if a small torque amplitude follows a big one. This trend cannot be confirmed with the perception quote. Beside the scaling factors the friction is one of the biggest influencing factors in this investigation. It became evident that the positioning accuracy can be decisively improved by the systematic use of friction. Often this is already valid with a little friction of 0.01 Nm. Though an even stronger friction improves the positioning accuracy even more, however, the improvement does not rise in the same degree like the amount of the friction. While there was no evidence from current state of research, in addition, the perception of differences also raises by the use of friction. In the end, for the implementation of a rotary knob with adaptive torque feedback in passenger cars a compromise must be reached between positioning accuracy and the perception of differences. For a high perception quote torque amplitudes must clearly differ from each other. However, big amplitude differences also lower the positioning accuracy. For this case, the described investigation offers possibilities to increase the positioning accuracy in spite of unfavourable amplitude combination by the kind of torque function and the addition of friction.
Active rotary knobs with adaptive torque feedback - conflict of goals between positioning accuracy and difference threshold
2011
15 Seiten, 8 Bilder, 1 Tabelle, 8 Quellen
Aufsatz (Konferenz)
Englisch