Barbara Deml

A study on visual, auditory, and haptic feedback for assembly tasks

Telepresent tasks involve removal of the human operator from an immediate working area and relocation to a remote environment that offers the operator all necessary control features. In this remote location, the operator must be provided with adequate feedback information such that the task at hand can be effectively executed. This research explores the effectiveness of various feedback methods. More specifically, graphical feedback in the form of video streamed images is compared against rendered 3D models, the overall effectiveness of haptic feedback is analyzed, and the influences of sensory augmentation and sensory substitution are examined. This study involved 48 participants, each of whom executed a simple clockwork assembly task under various feedback mechanisms. The results support the use of 3D models as opposed to live video streams for graphical presentation, utilization of haptic feedback (which was found to significantly enhance operation effectiveness), and the use of sensory augmentation and substitution under specific circumstances.

Evaluation of a vibrotactile feedback device for spatial guidance

In the present study, a vibrotactile feedback device for spatial guidance was evaluated in a tracking task paradigm. Participants (N = 18) had to translate and rotate virtual objects according to the vibrotactile vs. verbal cues without visual information. Both types of spatial guidance were evaluated using objective performance data (i.e. speed, accuracy) as well as subjective judgments. Results indicate that distinguishing spatial cues during the translational task was more difficult when being guided by vibrotactile feedback compared to verbal feedback. Nevertheless, individuals with vibrotactile guidance showed better performance at rotational tasks. Implications for the further design process and other areas of application are discussed.

Robot Assisted Force Feedback Surgery

Minimally invasive surgery characterizes a sophisticated operation technique in which long, slender instruments are inserted into the patient through small incisions. Though providing crucial benefits compared to open surgery (i.e. reduced tissue traumatization) it is also faced with a number of disadvantages. One of the major problems is that the surgeon cannot access the operating field directly and, therefore, can neither palpate tissue nor sense forces sufficiently. Furthermore, the dexterity of the surgeon is reduced as the instruments have to be pivoted around an invariant point.

Human Factors Issues on the Design of Telepresence Systems

The overall aim of this work is to provide some guidelines for the design of tele-presence systems from a human factors point of view. Developers of such human-machine systems face at least two major problems: There are hardly any standard input devices, and guiding design principles are almost missing. Further, most often telepresence systems should enable both a high degree of performance and a high sensation of presence, and yet the relationship between these two variables is still a subject of research. To cope with some of the problems, two experimental studies are presented. Each focuses on a different aspect of interface design, which is of widespread interest in the field of telepresence systems. The first is related to the control of multiple degrees of freedom and the second refers to bimanual input control. Beyond this work, a meta-analytical study is presented to describe the relationship between presence and performance more precisely. Certainly there are more issues that have to be studied (e.g., perceptual aspects) to guide the design of telepresence systems. To provide a framework for these and further human factor aspects, a computer based design guide is suggested at the end. This tool addresses system developers and assists in realizing new interfaces more effectively.

Electrocardiographic features for the measurement of drivers' mental workload

This study examines the effect of mental workload on the electrocardiogram (ECG) of participants driving the Lane Change Task (LCT). Different levels of mental workload were induced by a secondary task (n-back task) with three levels of difficulty. Subjective data showed a significant increase of the experienced workload over all three levels. An exploratory approach was chosen to extract a large number of rhythmical and morphological features from the ECG signal thereby identifying those which differentiated best between the levels of mental workload. No single rhythmical or morphological feature was able to differentiate between all three levels. A group of parameters were extracted which were at least able to discriminate between two levels. For future research, a combination of features is recommended to achieve best diagnosticity for different levels of mental workload.

A Contribution to Integrated Driver Modeling: A Coherent Framework for Modeling Both Non-routine and Routine Elements of the Driving Task

This paper is concerned with computational driver modeling, whereby a particular focus is placed on mapping both non-routine and routine elements of the driving task in a theoretically coherent framework. The approach is based on Salvuccis [1] driver model and thus, the cognitive architecture ACT-R [2] is used for modeling non-routine matters; for routine activities, such as the longitudinal and the lateral control of the vehicle, a fuzzy logic approach is suggested. In order to demonstrate the applicability of this procedure, an empirical evaluation study is carried out and the steering behavior of a computational driver model is compared to that of human drivers.

SIMULATING SURFACE ROUGHNESS IN VIRTUAL ENVIRONMENTS BY VIBRO-TACTILE FEEDBACK

Abstract One of the most important objectives of virtual environments is to provide an immersive rendering of real-world objects. It is assumed that human performance will be best if the operator is able to see, to touch, and to manipulate objects as he would do in everyday life. The main emphasis of this work is put on the immersive design of haptic feedback; thereby particularly the simulation of surface roughness in virtual scenarios is regarded in more detail. Below, both the actuator concept and the rendering approach of such a system are proposed (see Section 1). Afterwards the results of an experimental evaluation are presented (see Section 2, 3) and its impact on further research activities is discussed (see Section 4).

Untersuchung des Entscheidungsverhaltens in kooperativen Verkehrssituationen am Beispiel einer Engstelle

Zusammenfassung Eine der zukünftigen Herausforderungen, um einen erfolgreichen Mischverkehr zwischen automatisch geführten und von Menschen geführten Fahrzeugen zu bewältigen, ist, dass in kooperativen Situationen – z. B. an einer gleichrangigen Engstelle – die Teilnehmer am Straßenverkehr das Fahrverhalten des Gegenübers verstehen. Eine der Fragen, die Färber Färber, B. (2015). Kommunikationsprobleme zwischen autonomen Fahrzeugen und menschlichen Fahrern. In: M. Maurer, J. C. Gerdes, B. Lenz & H. Winner (Hrsg.), Autonomes Fahren. Technische, rechtliche und gesellschaftliche Aspekte. Berlin: Springer Vieweg. aufwirft, ist, ob Menschen in der Lage sind, schwierige kooperative Situationen mit automatisch geführten Autos zu bewältigen. Im täglichen Straßenverkehr haben Verkehrsteilnehmer die Möglichkeit, sich per expliziter oder impliziter Kommunikation an eine Engstelle zu nähern und so dem Gegenüber die eigene Intention zu vermitteln. In einem Quasi-Experiment (N = 22) wurden verschiedene Annäherungsweisen an eine gleichrangige Engstelle untersucht und u. a. das Entscheidungsverhalten sowie das Kommunikationsverhalten analysiert, um Rückschlüsse darüber ziehen zu können, wie sich automatisch geführte Autos in einer solchen Situation verhalten sollten. Auf diese Weise sollen die Verhaltensweisen herausgefiltert werden, die es ermöglichen, eine schwierig zu lösende Situation für beide Verkehrsteilnehmer adäquat zu bewältigen.

Scrutinizing pseudo haptic feedback of surface roughness in virtual environments

Operators in virtual environments have to mostly rely on visual feedback when exploring virtual scenes and objects. If no additional haptic actuators are available then information about surface roughness will not be communicable and thus the degree of immersion will suffer. To compensate for this shortcome the usage of pseudo haptic feedback (Control/ Display ratio = visual cues encoding haptic object properties) is discussed and two psychophysical experiments are conducted. The first experiment deals with the perceptual scaling of different Control/ Display ratios while the second experiment examines the way, how human subjects assign suitable Control/ Display ratios to different real surfaces. It turns out that human operators can reliably perceive differences in Control/ Display ratios and a psychophysic function is established. The allocation of specific Control/ Display values to real materials does not give any generalizable results; only a global trend is observable.

Gesture Recognition with Hidden Markov Models to Enable Multi-modal Haptic Feedback

The ability to recognize and classify human gestures bears a huge potential of improving haptic feedback in virtual environments: when it is possible to predict how a user wants to explore or manipulate his environment both the visual and the auditive feedback may be adapted in order to enhance the immersiveness of haptic displays. Within this work a software approach is suggested that allows for such a real-time classification of gestures in a continuous data stream. A visually based tracking system is used to record the hand movements, while Hidden Markov models are applied to analyze the data. After presenting the methodological background and the software implementation, the outcome of an evaluation study is discussed. It reveals satisfying results of gesture classification and, what is particularly important, the recognition is fast enough to enable multi-modal haptic feedback.