Principles of Telerobotics

The aim of designing and optimizing human-machine interfaces is not to faithfully represent the real world in the new world of interaction but to create a world for the operator that ensures immersion and performance. Immersion means that the user can be immersed in the system, potentially to the point of no longer being able differentiate between the real world and virtual reality. Performance is a measure of the quality of task accomplishment. Basic research of ways to provide such an environment has included feedback via different information channels:

  • haptic/kinesthetic feedback,
  • vision, visual feedback,
  • acoustic feedback.

Haptics/Kinesthetics

Haptic feedback is a central challenge in designing interfaces in the field of telerobotics. Put simply, haptics represent the sense that is relevant for grasping or touching objects. Haptic feedback, for example, allows us to grip a glass firmly enough to not drop it but gently enough to not break it. Kinesthesia or proprioception is the sense of self-movement and position of the joints, muscles and tendons. Fine-motor coordination requires both haptic and kinesthetic feedback.  

 

Thermal display

  

Cybertouch  

Cybergrasp

 

Literature

Nitsch, Verena; Färber, Berthold: "A Meta-Analysis of the Effects of Haptic Interfaces on Task Performance with Teleoperation Systems". In: IEEE Transactions on Haptics. 6, 2013, 4. - Pp. 387-398.

Hannig, Gunter: Modellierung multi-modaler haptischer Wahrnehmung; Dissertation Universität der Bundeswehr München, 2012.

Geiger, Lena; Popp, Michael; Färber, Berthold: Validation of a Testbed as a Screening Tool for Telepresence Systems in Terms of Fine-Motor-Performance Presence : Virtual and Augmented Reality, 20, 2, 2011 S. 162-172

Pongrac, Helena: Gestaltung und Evaluation von virtuellen und Telepräsenzsystemen an Hand von Aufgabenleistung und Präsenzempfinden. Dissertation UniBw. 2008
Deml, Barbara; Mihalyi, Andreas; Hannig, Gunter: Development and Experimental Evaluation of a Thermal Display; EuroHaptics 2006, Paris, France, 3-6 Juli 2006

Vision/Visual Feedback

Visual conditions and thus visual information in telepresence applications is affected by different parameters. Cameras cannot capture all views and angles. Transmission bandwidth affects image quality. If the operator sees the scene through a head-mounted display (HMD) – which has many advantages – the field of vision is limited. 

Head Mounted Display (HMD)

 

This has negative effects on the assessment of distances, performance quality in search tasks, identifying important objects and the operator’s wellbeing. One study examines whether supplementing video images with virtual reality can improve performance, situational awareness and the feeling of telepresence.


 

Literature

Deml, Barbara: Human Factors Issues on the Design of Telepresence Systems; Presence : Teleoperators and Virtual Environments

Deml, Barbara; Färber, Berthold: Telemanipulation und virtuelle Realität; Enzyklopädie der Psychologie. Themenbereich D. Praxisgebiete, Ser. 3. Wirtschafts-, Organisations- und Arbeitspsychologie, Bd. 2. Ingenieurpsychologie

Pongrac, Helena; Leupold, Jan; Behrendt, Stephan; Färber, Berthold; Färber, Georg: Human Factors for Enhancing Live Video Streams with Virtual Reality. Performance, Situation Awareness, and Feeling of Telepresence. In: Presence : Teleoperators and Virtual Environments, 16, 5. MIT Press, 2007. S. 488-508
 

Acoustic Feedback

Humans are “multisensory information processors”. Despite the dominance of the visual sense, haptic and acoustic information also play an important role. Studies on the influence of acoustic information focus on localization and navigation tasks. For one thing, they demonstrate that when it comes to these specific tasks, both auditive and haptic feedback are inferior to visual feedback. What is more, the combination of haptic or acoustic information with visual information does not lead to better performance on this type of task compared with purely visual information, either.


Literature

Benz, Tobias M.; Nitsch, Verena: “Understanding Ambiguous Effects of Multimodal Feedback on Situation Awareness and Task Performance Using Bayes Sense Integration” In: Proceedings of the 3rd Berlin Summer School Human Factors, 2017.

Benz, Tobias M.; Nitsch, Verena: „Using Multisensory Cues for Direction Information in Teleoperation“. In: IEEE International Conference on Robotics and Automation, Singapore, 2017.

Data Compression and Transmission

If the operator and the teleoperator are located far apart and bandwidth is limited, there will be lags or gaps in data transmission. Delayed or missing feedback leads to impaired performance. This problem can be solved with what we know about perception. 

Weber’s law states that the just-noticeable increase in the intensity of a stimulus is a constant proportion of the intensity of the initial stimulus.

 

     

If you light a candle in a dark room, the difference in brightness is obvious. If, however, 50 candles are already burning and you add one more, the difference will not be noticeable.

 

Perception-Based Data Compression

  

This principle can be applied to the compression of haptic data in order to reduce the data transmission rate. Only the black values are transmitted (see above). Only when there is a significant change will a new value be transmitted. This makes it possible to reduce the data rate by more than 90% without impairing perceived quality or task performance.

 

Literature

Nitsch, Verena; Kammerl, Julius; Färber, Berthold; Steinbach, Eckehard: "On the Impact of Haptic Data Reduction and Feedback Modality on Quality and Task Performance in a Telepresence and Teleaction System". In: Kappers, A.M.L. et al. (EDs.): Haptics: Generating and Perceiving Tangible Sensations. International Conference, EuroHaptics 2010, Amsterdam, July 2010, Proceedings, Part I. - Pp. 169 – 176. Springer-Verlag Berlin.

Kammerl, Julius; Vittorias, Iason ; Nitsch, Verena; Färber, Berthold; Steinbach, Eckehard; Hirche, Sandra: "Perception-Based Data Reduction for Haptic Force-Feedback Signals Using Velocity-Adaptive Deadbands". In: Presence, Teleoperation and Virtual Environments, 19, 2010, 5. – Pp. 450-462. MIT Press.

Freyberger, Franziska: "Gestaltung visuell-haptischer Telepräsenz- und Teleaktionssysteme mittels psychologischer Grundlagen". Dissertation UniBw, 2008.

Pongrac, Helena; Leupold, Jan; Behrendt, Stephan; Färber, Berthold; Färber, Georg: “Human Factors for Enhancing Live Video Streams with Virtual Reality, Performance, Situation Awareness, and Feeling of Telepresence” In: Presence : Teleoperators and Virtual Environments, MIT Press, 2007, S. 488-508.

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