A robot swarm assisting a human fire-fighter

Emergencies in industrial warehouses are a major concern for fire-fighters. The large dimensions, together with the development of dense smoke that drastically reduces visibility, represent major challenges. The GUARDIANS robot swarm is designed to assist fire-fighters in searching a large warehouse. In this paper we discuss the technology developed for a swarm of robots assisting fire-fighters. We explain the swarming algorithms that provide the functionality by which the robots react to and follow humans while no communication is required. Next we discuss the wireless communication system, which is a so-called mobile ad-hoc network. The communication network provides also the means to locate the robots and humans. Thus, the robot swarm is able to provide guidance information to the humans. Together with the fire-fighters we explored how the robot swarm should feed information back to the human fire-fighter. We have designed and experimented with interfaces for presenting swarm-based information to human beings

Topology Control in Large-Scale High Dynamic Mobile Ad-Hoc Networks

El-Habbal M, Rückert U, Witkowski U. Topology Control in Large-Scale High Dynamic Mobile Ad-Hoc Networks. In: Proceedings of the FIRA RoboWorld Congress 2009 on Advances in Robotics. Berlin, Heidelberg: Springer-Verlag; 2009: 239-250.We present our contribution in projects related to ad-hoc networking using different routing protocols and hardware platforms, showing our results and new solutions regarding topology control and routing protocols. We mainly focus on our work in the GUARDIANS EU-project, where as a main disaster scenario a large industrial warehouse on fire is assumed. The paper presents the simulation results for the routing protocols ACR, DSR and EDSR, as well as the implementation of down-scaled demos for supporting the autonomous team of robots as well as the human squad team with robust communication coverage. Various hardware platforms were used in the demos for distance measurement, based on laser range finder and radio communication with time of flight analysis

Mobile Ad-hoc Communication applied and optimized for disaster scenarios

El Habbal MAM, Witkowski U, Rückert U. Mobile Ad-hoc Communication applied and optimized for disaster scenarios. In: Wireless Technologies Kongress 2008. Bochum, Germany; 2008: 25-34

FPGA based speech processing for the Khepera Robot

El Habbal MAM, Witkowski U, Rückert U. FPGA based speech processing for the Khepera Robot. In: 4th International Symposium on Autonomous Minirobots for Research and Edutainment (AMiRE). Buenos Aires, Argentina; 2007

Robust Multihop Communication for Mobile Applications

Herbrechtsmeier S, El Habbal MAM, Rückert U, Witkowski U. Robust Multihop Communication for Mobile Applications. In: Proceedings of IARP Workshop on Robotics for Risky Interventions and Environmental Surveillance (RISE) 2010. 2010.This paper focuses on node placement strategy, communication protocols and hardware implementation of a robust mobile multi-hop network. As part of the GUARDIANS project a main disaster scenario of a large industrial warehouse on fire is assumed. In this scenario, black smoke may fill large space of the warehouse which makes it very difficult for the firefighters to locate themselves and orientate in the building. In our approach a multi-hop ad-hoc network communication system is able to provide a robust communication system. Focus of this paper is the distribution of robots to guaranteeing robust communication between the base station outside the scenario area and the fire fighter inside the building. Concerning the first point, the presence of smoke and the indoor nature of our scenario prevent localization using camera and GPS respectively. Therefore the performance and accuracy of other sensors were tested in order to examine their usability and reliability in such a scenario, like ultra-sound, laser and radio signaling. The second point is the evaluation of routing protocols and the development of a mobile communication gateway which is optimized for the mobile usage and therefore supports different techniques for energy saving. Its characteristic was tested in different scenarios like a complex building and a parking garage

Ad-hoc Network Communication Infrastructure for Multi-robot Systems in Disaster Scenarios

Witkowski U, El Habbal MAM, Herbrechtsmeier S, et al. Ad-hoc Network Communication Infrastructure for Multi-robot Systems in Disaster Scenarios. In: Proceedings of IARP/EURON Workshop on Robotics for Risky Interventions and Environmental Surveillance (RISE 2008), Benicassim, Spain. 2008.Mobile ad-hoc networks (MANETs) are communication networks that do not rely on fixed, preinstalled communication devices like base stations or predefined communication cells. MANETs are wireless networks consisting of mobile nodes which are characterized by their decentralized organization and the potentially high dynamics of the network structure. Therefore, MANETs are ideally suitable for applications with multi-robot systems. One of the most promising applications of a multi-robot system is to assist humans in urban search and rescue (USAR) scenarios in the aftermath of natural or man-made disasters. We are focusing on an ad-hoc network communication system with the mobile robots being communication nodes offering a robust communication infrastructure. Main disaster scenario covered by our system is a large industrial warehouse in fire, described in the GUARDIANS project funded by the European Union. In this scenario, black smoke may fill large space of the warehouse that makes it very difficult for the firefighters to orientate themselves in the building which in turn will usually limit the action space of the firefighters. In order to increase the coverage area of the fire fighters the ad-hoc network has to provide position data to support localization of the mobile robots and humans, which might be of great importance to guide the humans and robots to specific targets and locations or to quickly exit the search area. In our proposed approach a cell-based network with master nodes in each cell forms the basic structure of the network. Some nodes formed by speciallyequipped robots act as beacons to uniformly span the network. These robots have a role as reference points when positioning other mobile robots or humans and at the same time form the infrastructure to support communication all over the search area. A combination of distance and radio signal quality measurements as well as dedicated swarming behaviors of the robots are capable of maintaining suitable distribution of the robots even in the presence of walls that obstruct the radio signals. Communications standards considered for the ad-hoc network are Wireless LAN, Bluetooth and QigBee. All are integrated on a miniature robot for real experiments. The features of the network are studied analytically, in simulations as well as in experiments to verify the results. Furthermore, frequency and power managements are also taken into consideration to ensure robustness of communication in the network

Self-Optimizing Human-Robot Systems for Search and Rescue in Disaster Scenarios

Witkowski U, Herbrechtsmeier S, Tanoto A, et al. Self-Optimizing Human-Robot Systems for Search and Rescue in Disaster Scenarios. In: Proceedings of the 7th International Heinz Nixdorf Symposium. 2008.The increasing capabilities of robot systems enable new fields of practical applica- tions for individual robots as well as multi-robot systems. But for some applica- tion scenarios like a fire or earthquake disaster current robots are still too limited to act fully autonomously in the disaster area. To overcome these limitations we consider a heterogeneous team of humans and robots complementing each other. Core application considered in this paper is a large burning warehouse with smoke making it difficult for fire fighters to search the building and to orientate them- selves inside the warehouse. Therefore, an assisting team of robots is surrounding the fire fighters searching the proximity, providing orientation data, and establish- ing a wireless communication infrastructure on a basis of a mobile ad-hoc net- work. The adaptation of the robots is achieved by applying principles of self- optimization on different levels of the human-robot system. In this paper, we are considering self-optimization inside an individual robot to optimize its behaviour, within a group of robots, and in the entire system compris- ing of robots and humans. The focus of the optimization is the distribution of ro- bots by applying swarming behaviour for forming a mobile ad-hoc communica- tion network and performing map building

Powerful Miniature Robot for Research and Education

Witkowski U, Herbrechtsmeier S, El Habbal MAM, Rückert U. Powerful Miniature Robot for Research and Education. In: IEEE Proceedings of the, 5th International Conference on Computational Intelligence, Robotics and Autonomous System (CIRAS 2008), June 19 – 21, Linz, Austria. 2008

Ischemic stroke complicating thrombolytic therapy with tenecteplase for ST elevation myocardial infarction: two case reports

Abstract Background Hemorrhagic complications are quite common in the rare cases where thrombolysis is performed. Ischemic stroke in the aftermath of thrombolysis for a ST elevation myocardial infarction is a very rare and paradoxical complication. With these observations in mind we report two interesting cases of ischemic stroke which occurred after fibrinolytic therapy with tenecteplase for a ST elevation myocardial infarction. Case presentation The first case was a 56-year-old African man who presented with an acute infero-basal ST elevation myocardial infarction 6 hours after chest pain onset. Thrombolysis with tenecteplase was performed and few minutes later an ischemic stroke occurred. The second patient was a 65-year-old African man who presented with an acute infero-basal ST elevation myocardial infarction 5 hours after chest pain onset. Thrombolysis was performed and 10 hours later an ischemic stroke occurred. Conclusions Hemorrhagic stroke is not the only complication of thrombolysis, ischemic stroke can occur even if it is an extremely rare complication. The two cases on which we report shed light on the association between fibrinolytic therapy and ischemic stroke, the pathophysiology of which is not well understood