Publications

Srinivasan, L.; Baier, P.; Herrmann, C.; Scharnagl, J.; Schilling, K.;
Redefining voting to enable simultaneous multioperator robot navigation
3rd IFAC Workshop on Internet Based Control Education , 2015. p.170-175, DOI: 10.1016/j.ifacol.2015.11.232
[BibTeX]

@inproceedings{srini2015b, author = {L. Srinivasan and P. Baier and C. Herrmann and J. Scharnagl and K. Schilling}, title = {Redefining voting to enable simultaneous multioperator robot navigation}, booktitle = {3rd IFAC Workshop on Internet Based Control Education }, year = {2015}, pages = {Coming soon}, city = {Brescia}, month = {November}, country = {Italy}, DOI = {10.1016/j.ifacol.2015.11.232} }

[Abstract]

This paper details an algorithm where multiple users can simultaneously and efficiently operate on a single remote robot. Single user single robot remote operation is fairly advanced but multi-user operation is faced with many drawbacks, especially when users are spatially seperated and have no means of knowing what commands are being issued by other operators at the same time. This is a non-trivial problem and has so far always been solved using human intervention using built in voting mechanisms. This paper is focussed on using an intelligent voting algorithm which dynamically computes a vote based on operator commands without the need for any manual intervention. Extended results are documented and analysed.

Baier,P.; Srinivasan, L.; Baier, J.; Voelker, W.; Schilling, K.;
Surfaces for modeling arteries in virtual reality simulators
3rd IFAC Workshop on Internet Based Control Education , 2015. p.31-35, DOI: 10.1016/j.ifacol.2015.11.209
[BibTeX]

@inproceedings{baier2015a, author = {P. Baier and L. Srinivasan and J. Baier and W. Voelker and K. Schilling}, title = {Surfaces for modeling arteries in virtual reality simulators}, booktitle = {3rd IFAC Workshop on Internet Based Control Education }, year = {2015}, pages = {Coming soon}, city = {Brescia}, month = {November}, country = {Italy}, DOI = {10.1016/j.ifacol.2015.11.209} }

[Abstract]

Coming soon

Srinivasan, L.; Scharnagl, J.; Herrmann, C.; Schilling, K.;
Adaptive teleoperation using intelligent dynamic voting
Conference on Embedded Systems, Computational Intelligence and Telematics in Control, 2015. p. 111–116, DOI: 10.1016/j.ifacol.2015.08.117
[BibTeX]

@inproceedings{srini2015a, author = {L. Srinivasan and J. Scharnagl and C. Herrmann and K. Schilling}, title = {Adaptive teleoperation using intelligent dynamic voting}, booktitle = {Conference on Embedded Systems, Computational Intelligence and Telematics in Control}, year = {2015}, volume = {48}, pages = {111–116}, city = {Maribor}, month = {June}, DOI = {doi:10.1016/j.ifacol.2015.08.117} }

[Abstract]

This paper addresses the design of an adative teleoperation framework for spatially displaced robotics. Although teleoperation controllers have been optimized and frameworks developed for single user single robot teleoperation, the same cannot be said for multi-user control of a single remote agent. Typical collaborative teleoperation consists of a group of people working on a single remote robotic system with a user voting interface to decide on the commands sent to the robot. These are majority based systems and just like in a democracy, problems occur. This research is focussed on a system that uses an intelligent and adaptive dynamic voting paradigm in order to enable adaptive teleoperation.

Scharnagl, J.; Srinivasan, L.; Ravandoor, K.; Schilling, K.;
Automated Collision Avoidance for Rendezvous and Docking in Space
Workshop on Advanced Control and Navigation for Autonomous Aeroespace Vehicles, 2015. p. 239-244, DOI: 10.1016/j.ifacol.2015.08.090
[BibTeX]

@inproceedings{scharnagl2015a, author = {J. Scharnagl and L. Srinivasan and K. Ravandoor and K. Schilling}, title = {Automated Collision Avoidance for Rendezvous and Docking in Space }, booktitle = {Workshop on Advanced Control and Navigation for Autonomous Aeroespace Vehicles}, year = {2015}, pages = {239-244}, city = {Seville}, month = {June}, DOI = {10.1016/j.ifacol.2015.08.090} }

[Abstract]

In this paper a collision avoidance system is presented that is especially designed for close range maneuver in space, like rendezvous and docking and on-orbit servicing. Based on relative position and orientation information from a visual sensor the future trajectory of an observed target spacecraft is predicted. Possible collisions on that trajectory are detected and, in the event of an imminent collision, the required velocity corrections (dV) to perform a collision avoidance maneuver to a safe hold point are calculated. In addition to that, approach corridor and velocity profile as well as minimum distance are considered as trigger criteria. dV computation is based on Hill-Clohessy-Wiltshire equations using specific constraints for intended hold point position on V-bar. The system has been implemented and tested in a hardware-in-the-loop setup at University of Würzburg that consists of two industrial manipulators holding a Photonic Mixer Device camera and a satellite mockup model.

Scharnagl, J.; Kleinschrodt, A.; Freimann, A.; Ravandoor, K.; Bangert, P.; Srinivasan, L.; Schilling, K.;
Nanosatellite Constellations for Large-Scale Railway Transportation Monitoring
Proceedings of the 3rd IAA Conference on University Satellite Missions and CubeSat Workshop. Rome, Italy 2015. p.
[BibTeX]

@inproceedings{scharnagl2015b, author = {Scharnagl, Julian and Kleinschrodt, Alexander and Freimann, Andreas and Ravandoor, Karthik and Bangert, Philip and Srinivasan, Lakshminarasimhan and Schilling, Klaus}, booktitle = {Proceedings of the 3rd IAA Conference on University Satellite Missions and CubeSat Workshop}, publisher = {IAA}, title = {{Nanosatellite Constellations for Large-Scale Railway Transportation Monitoring}}, year = {2015} }

[Abstract]

In the recent past, large-scale railway transportation became increasingly important since it is more eco-friendly and more cost- efficient than transportation by sea or air. At present, the lack of system-optimization and reliability are key problems of railway transportation, especially in areas with poor infrastructure. Inter- continental trains need to travel through secluded areas, where only minimal area-wide mobile data communication is available at high costs. We propose a system using a constellation of nanosatellites for monitoring large scale railway transportation. Requirements are established for a nanosatellite platform including the corresponding payloads on the satellite and the cargo containers for trains. We also propose a concept for the design of a constellation of nano- satellites. Application driven monitoring scenarios with different degrees of coverage ranging from the observation of a single railway line (Trans-Siberian Railway from Moscow to Beijing) to global cov- erage are discussed.

Srinivasan, L.; Schilling, K.;
Telerobotics for Education: A Marriage of Pedagogy and Technology Management
Advances in Control Education, Volume # 10 | Part# 1. 2013. DOI: 10.3182/20130828-3-UK-2039.00076
[BibTeX]

@inproceedings{srini2013a, author = {L. Srinivasan and K. Schilling}, title = {Telerobotics for Education: A Marriage of Pedagogy and Technology Management}, booktitle = {Advances in Control Education, Volume # 10 | Part# 1}, year = {2013}, pages = {198-202}, city = {Sheffield}, DOI = {10.3182/20130828-3-UK-2039.00076} }

[Abstract]

Distance learning need not always be benchmarked against classroom learning. Common research patterns suggest a tendency to want to converge remote learning to its traditional counterpart, but an experience of running a tele-education robotics course for over 10 years indicates this is not necessary for effective education. An important reason why tele-laboratories and remote learning courses fail after an initial hype could be a lack of focus on technology management including state of the art from concerned fields including pedagogy and technology, and consider cultural change impacting student models with passing generations of students. This work describes how our tele-laboratory was designed and built, how student numbers started dropping after the first five years and what has been changed in the last three years to attract students. A statistical analysis of student numbers and anonymous feedback is also presented to show how interest has been rekindled and how word-of-mouth publicity has resulted in students from newer institutions across Germany taking up our course. Results from an independent review of the course conducted by the Virtual University of Bavaria, of which our tele education course is a part since 2005, are also presented corroborating other results in this paper.

Srinivasan, L.; Schilling, K.;
Augmented Reality Navigation Paradigm for Time Delayed Teleoperation
Telematic Applications, Volume # 3 | Part# 1. 2013. DOI: 10.3182/20131111-3-KR-2043.00002
[BibTeX]

@inproceedings{srini2013b, author = {L. Srinivasan and K. Schilling}, title = {Augmented Reality Navigation Paradigm for Time Delayed Teleoperation}, booktitle = {Telematic Applications, Volume # 3 | Part# 1}, year = {2013}, pages = {1-6}, city = {Seoul}, month = {November}, DOI = {10.3182/20131111-3-KR-2043.00002} }

[Abstract]

What has so far not been published, is the effect of changing the way human teleoperators are allowed to navigate from a time delayed state. This paper describes the implementation and evaluation of a new paradigm for time delayed teleoperation - exocentric navigation and publishes experimental results of this paradigm in comparison with the more commonly used navigation algorithm which will be termed egocentric navigation. A typical example for egocentric navigation is steering of a car, where navigation is a continuous process with orientation and displacement occurring simultaneously. Exocentric navigation approaches the navigation problem as a two step process, orientation followed by displacement. It can be viewed as partial autonomy in navigation, where orientation is autonomously performed by the remote robot without assistance and displacement is determined by the human operator using, in most instances, a joystick that controls both direction and speed. Evaluation of the exocentric paradigm consists of testing it with respect to navigation, perception and manipulation. System performance is measured in terms of navigation times and number of collisions and operator performance is measured using Situational Awareness Global Assessment Technique (SAGAT). The new paradigm is tested on users both with and without prior experience with results aimed at aiding human operator training.

Srinivasan, L.; Scharnagl, J.; Xu, Z.; Faerber, N.; Kumar B.D.; Schilling, K.;
Design and Development of a Robot Teleoperation System Using Duplex WebSockets Suitable for Variable Bandwidth Networks
Telematic Applications, Volume # 3 | Part# 1. 2013. DOI: 10.3182/20131111-3-KR-2043.00029
[BibTeX]

@inproceedings{srini2013c, author = {L. Srinivasan and J. Scharnagl and Z. Xu and N. Faerber and B.D. Kumar and K. Schilling}, title = {Design and Development of a Robot Teleoperation System Using Duplex WebSockets Suitable for Variable Bandwidth Networks}, booktitle = {Telematic Applications, Volume # 3 | Part# 1}, year = {2013}, pages = {57-61}, city = {Seoul}, month = {November}, DOI = {10.3182/20131111-3-KR-2043.00029} }

[Abstract]

This paper addresses the development of a new teleoperation framework for remote robotics. The status of existing robotic teleoperation systems is introduced, with emphasis on several technological drawbacks and is followed by a description of the design, development and implementation of a new framework based on bleeding edge technologies in internet protocols and software engineering related to robotics. As a first implementation, an update of an existing tele-robotics laboratory is in progress aiming round-the-clock networked access, suited for even the most demanding online learning platforms. A comparison between the current and previous teleoperation system is also published verifying the implemented framework.

Srinivasan, L.; Scharnagl, J.; Schilling, K.;
Analysis of WebSockets As the New Age Protocol for Remote Robot Tele-Operation
Telematic Applications, Volume # 3 | Part# 1. 2013. DOI: 10.3182/20131111-3-KR-2043.00032
[BibTeX]

@inproceedings{srini2013d, author = {L. Srinivasan and J. Scharnagl and K. Schilling}, title = {Analysis of WebSockets As the New Age Protocol for Remote Robot Tele-Operation}, booktitle = {Telematic Applications, Volume # 3 | Part# 1}, year = {2013}, pages = {83-88}, city = {Seoul}, month = {November}, DOI = {10.3182/20131111-3-KR-2043.00032} }

[Abstract]

This paper addresses the replacement of acknowledgement based protocols for teleoperation. The initial sections compare the currently used protocols like HTTP and TCP to WebSockets and examine the structural difference of using one over the other, for a real-time teleoperation scenario. A detailed analysis of HTTP and WebSockets is performed using live teleoperation by multiple users performing temporally seperated tests under variably delayed network conditions. The existing teleoperation laboratory at the University of Wuerzburg was used as the test bed to compare these protocols and final teleoperation results in terms of bandwidth, frame-rate, navigation efficiency and situational awareness are presented and discussed.