Schlüsselwort: Haptische Informationsübertragung

The steady rise in the amount of controllable functions and control elements of technical appliances, in particular within the automotive sector and the thereto-relating increase of visual indications lead to an overload of the human visual perception channel as well as a negative influence on the operating safety. Consequently, central control elements, which combine various functions, come into action more and more frequently. The information display is thereby separated from the information selection. The displays are positioned in the optimum, mostly peripheral field of view of the driver, whereby, in theory, allowing the driver to quickly avert their gaze. Nonetheless, a visual and cognitive distraction occurs during the operation [RASSL 2004, S.65-66], [ZEILINGER 2005, S. 7]. To remedy this problem new control system are necessary. The distraction of the driver can be reduced by equipping already existing central control elements, usually a rotary control element with an active haptic signal. Through a situative and contextdependent adaption of the controlling torques certain information contents of a display can be transmitted not only visually but also with a haptic encoding without the need for turn of the head. It is the key objective of this dissertation to derive design proposals for controlling torques of rotary control elements, which can be used to transmit information haptically in the context of a primary and secondary task. Furthermore, this paper examines how certain information content can be constituted haptically and which haptic characteristic is preferred by users to code certain information content. For this purpose basic concepts will be introduced initially (chapter 2), which directly correlate with the present research topic. In addition to the human-machine interface and the related displays and control elements, the human being and its capabilities to perceive and process information will be observed. Therefore, the information transmission process and the perception process, but also the system boundary of this work, will be regarded and defined. Chapter 3 deals with the state of the art and research. Rotary control elements with haptic signal are introduced and the status in the automotive sector covered. When presenting the state of research, studies are introduced, which deal with the interpretation of controlling torques of rotary control elements. Emphasis is hereby placed on HAMPEL [2011] since this research paper is based on his work. His design recommendations however rest upon a pure adjusting purpose. Whether his values are also valid in the context of a primary and secondary task, or if other values need to be considered, is part of this research paper and forms the demarcation to his work. Chapter 4 concretizes and derives examination parameters relevant to this work. First visual displays and their information content are analyzed and the contents gradually selected, which are examined within this work. Subsequently haptic characteristics of a rotary control element are derived and evaluated considering the chosen information content and chosen for the examination. Two test series will be conducted (chapter 5) in which 30 test subjects participated respectively. The ratio between male and female test persons consists of 60:40 in each test series. The test subjects mainly come from the university environment (students and academic employees) and have an average age of 25 years. Aside from typical data about the test persons (gender, age, occupation, etc.) their motoric capability is measured. For this purpose a test method of the Vienna Test System is applied. A standardized driving simulation (Lange Change Test) is used as primary task, which was developed especially for the examination of in-vehicle human-machine interfaces in context of primary and secondary task. The secondary task consists of linear actuation on the torque test bench, with which the to-be examined parameters of the relating test series can be generated and examined. Figure 1 shows the schematic experimental setup of the two test series. The first test series examines 16 different parameter combinations. Further parameter combinations are derived based on the recommended parameter combination from HAMPEL [2011] (amplitude 0,09 Nm and rotary angle 24°) and examined with regard to objective and subjective measuring criteria. Task fulfillment, positioning time, as well as deviation in the Lane Change Test, belong to the objective criteria. The subjective criteria include the author’s appraisal of the test subjects regarding the task fulfillment, the precision, as well as the applied actuating power. The results are evaluated in a descriptive (bar- and box-plot display) and inferential statistic (primarily via the Friedman- Test) manner as well as compared to each other. It is shown that an amplitude of 0,09 Nm and a rotary angle of 30° are to be used. Based on these results the second test series examines how the in chapter 4 derived information content can be transmitted haptically encoded. For this, the characteristics of the derived haptic features (amplitude changes, rotary changes, and combinations thereof) are interpreted first and examined subsequently. 14 different parameters are defined in total. Under consideration of the derived information content "center mark", "preferred value" and "menu change" two options occur regarding the potential structure of the haptic characteristics of these parameters. The haptic feature has to be symmetric around the relating snap-in point and can only refer to one snap-in point in order to display a "center mark" or "preferred value" through a rotary control element haptically encoded. However, this type of identification of a "menu change" is unsuitable. For this the haptic feature has to have an asymmetrical set up. For this purpose, a duplicate design consisting of 14 symmetrical and 14 asymmetrical parameters is used to examine the 14 parameters. The results show that within both test series (symmetrical and asymmetrical) parameters with a haptic characteristic in the form of an amplitude and rotary change deliver the best results. In both cases the amplitude change shall show a scaling factor of 1,9 while the rotary change shall show a scaling factor of 1,56 to the respective initial value. Lastly, research concentrates on defining which haptic features are ideally suited to label the derived information content ("center mark", "preferred value" and "menu change"). It is shown that a haptic characteristic in the form of a pure amplitude change shall be used for the labelling of a "center mark". However, for the labelling of a "preferred value" a haptical characteristic, consisting of an amplitude and rotary change shall be used. The same applies for a "menu change" – whereby the construction shall be asymmetrical. This study concludes with design recommendations in chapter 6. ..weiterlesen