Perceived realism of haptic rendering methods for bimanual high force tasks: original and replication study.

Realistic haptic feedback is a key for virtual reality applications in order to transition from solely procedural training to motor-skill training. Currently, haptic feedback is mostly used in low-force medical procedures in dentistry, laparoscopy, arthroscopy and alike. However, joint replacement procedures at hip, knee or shoulder, require the simulation of high-forces in order to enable motor-skill training. In this work a prototype of a haptic device capable of delivering double the force (35 N to 70 N) of state-of-the-art devices is used to examine the four most common haptic rendering methods (penalty-, impulse-, constraint-, rigid body-based haptic rendering) in three bimanual tasks (contact, rotation, uniaxial transition with increasing forces from 30 to 60 N) regarding their capabilities to provide a realistic haptic feedback. In order to provide baseline data, a worst-case scenario of a steel/steel interaction was chosen. The participants needed to compare a real steel/steel interaction with a simulated one. In order to substantiate our results, we replicated the study using the same study protocol and experimental setup at another laboratory. The results of the original study and the replication study deliver almost identical results. We found that certain investigated haptic rendering method are likely able to deliver a realistic sensation for bone-cartilage/steel contact but not for steel/steel contact. Whilst no clear best haptic rendering method emerged, penalty-based haptic rendering performed worst. For simulating high force bimanual tasks, we recommend a mixed implementation approach of using impulse-based haptic rendering for simulating contacts and combine it with constraint or rigid body-based haptic rendering for rotational and translational movements.

Two is Better Than One. Improved Attention Guiding in AR by Combining Techniques.

Search tasks in production environments have been shown to be significantly improved by attention guiding techniques in augmented reality (AR). In mobile use cases, head-mounted displays support context-sensitive and flexible search tasks. To improve search time and navigation efficiency, first concepts like attention funnel and spherical wave based guidance techniques have been tested successfully in comparison to simple arrow navigation. Existing research indicates that for two-dimensional interfaces, a differentiation into coarse and fine navigation will result in further performance improvements. In this article, a laboratory study is presented with a stereoscopic head-mounted display that examines whether an additional arrow guiding technique for coarse navigation could improve both search time and efficiency of existing techniques. Results show objectively superior performance for one of the combined techniques in comparison to the unimodal attention guiding techniques and subjective preference by the participants. Further research should investigate the performance in a real environment.

Get a grip: multi-method evaluation of handles for tablets on the shop floor.

Tablets on the shop floor need handles because user requirements for handling differ from tablet usage in leisure time. The ergonomics of such handles is under-researched, resulting in a lack of methods for their design and evaluation. In this paper, we present a multi-method evaluation of handles for a shop floor tablet. We combine and compare results of focus groups and the Comfort Questionnaire for Hand tools (CQH) with electromyography (EMG). With a field and a laboratory study, we evaluate four handles in order to identify (i) the most ergonomically rated handle and (ii) the most efficient evaluation method. Results consist of an evaluated prototype, and data that shows the comparability of results from focus groups and questionnaires to results from EMG measurements. Classifying handles as tangible human machine interfaces, we suggest that subjective evaluation with focus groups and CQH is efficient to evaluate their ergonomic quality. Practitioner summary: A handle for a tablet used in production environment is evaluated with different methods. Results show that data from focus groups and questionnaires can be used for evaluation of usability in the future, rendering complex EMG measurements unnecessary and making usability evaluation more efficient. Abbreviation: CQH: comfort questionnaire for hand tools; EMG: electromyography; tHMI: tangible human-machine interfaces; TUI: tangible user interfaces; GUI: user interface; RMS: root mean square; MVC: maximum voluntary contraction; BB: musculus biceps brachii; FCU: musculus flexor carpi ulnaris; FCR: musculus flexor carpi radialis; BR: musculus brachioradialis; FPB: musculus flexor pollicis brevis.

Mitigating passive fatigue during monotonous drives with thermal stimuli: Insights into the effect of different stimulation durations.

Driving on monotonous roads has been shown to cause passive fatigue as even non-sleep-deprived drivers suffer from the lack of stimuli. Consequently, alertness is reduced and the risk of accidents increases. To counteract this risk, measures need to be taken to mitigate driver fatigue. While in the past, some studies have been focused on the potential of thermal stimuli to reduce fatigue, their results seem inconclusive. Examining the study conditions in which the thermal stimuli were studied, it becomes obvious that the duration of the thermal stimulus strongly affects perceived fatigue. To better understand this relation, a driving simulator study (n=33) was conducted investigating both a 2min and a 4min thermal stimulus (15öC), where air was circulated on non-sleep-deprived drivers. For the 4min stimulus, patterns of increased sympathetic activity (i.e. significant pupil dilatation and bradycardia) were recorded. Furthermore, participants subjectively rated fatigue significantly lower when the stimuli were applied, and preferred driving with the stimulus. The superior performance of the 4min stimulus can be derived from a longer effect on the physiological data as well as even lower subjective fatigue ratings. Results also point to the limits of thermal stimulation: 6min after the stimuli, the participants no longer feel an effect (based on subjective ratings). Future research on passive fatigue countermeasures should hence build on the identified effect of a 4min cooling stimulus to increase physiological arousal and focus on the opportunities to increase effect duration.

Psychophysiological responses to short-term cooling during a simulated monotonous driving task.

For drivers on monotonous routes, cognitive fatigue causes discomfort and poses an important risk for traffic safety. Countermeasures against this type of fatigue are required and thermal stimulation is one intervention method. Surprisingly, there are hardly studies available to measure the effect of cooling while driving. Hence, to better understand the effect of short-term cooling on the perceived sleepiness of car drivers, a driving simulator study (n = 34) was conducted in which physiological and vehicular data during cooling and control conditions were compared. The evaluation of the study showed that cooling applied during a monotonous drive increased the alertness of the car driver. The sleepiness rankings were significantly lower for the cooling condition. Furthermore, the significant pupillary and electrodermal responses were physiological indicators for increased sympathetic activation. In addition, during cooling a better driving performance was observed. In conclusion, the study shows generally that cooling has a positive short-term effect on drivers' wakefulness; in detail, a cooling period of 3 min delivers best results.

Open innovation in health care: analysis of an open health platform.

Today, integration of the public in research and development in health care is seen as essential for the advancement of innovation. This is a paradigmatic shift away from the traditional assumption that solely health care professionals are able to devise, develop, and disseminate novel concepts and solutions in health care. The present study builds on research in the field of open innovation to investigate the adoption of an open health platform by patients, care givers, physicians, family members, and the interested public. Results suggest that open innovation practices in health care lead to interesting innovation outcomes and are well accepted by participants. During the first three months, 803 participants of the open health platform submitted challenges and solutions and intensively communicated by exchanging 1454 personal messages and 366 comments. Analysis of communication content shows that empathic support and exchange of information are important elements of communication on the platform. The study presents first evidence for the suitability of open innovation practices to integrate the general public in health care research in order to foster both innovation outcomes and empathic support.