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Nikolakopoulos, GeorgeORCID iD iconorcid.org/0000-0003-0126-1897
Publications (10 of 136) Show all publications
Röijezon, U., Prellwitz, M., Innala Ahlmark, D., van Deventer, J., Nikolakopoulos, G. & Hyyppä, K. (2019). A haptic navigation aid for individuals with visual impairments: Indoor and outdoor feasibility evaluations of the LaserNavigator. Journal of Visual Impairment & Blindness, 113(2), 194-201
Open this publication in new window or tab >>A haptic navigation aid for individuals with visual impairments: Indoor and outdoor feasibility evaluations of the LaserNavigator
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2019 (English)In: Journal of Visual Impairment & Blindness, ISSN 0145-482X, E-ISSN 1559-1476, Vol. 113, no 2, p. 194-201Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Sage Publications, 2019
National Category
Physiotherapy Occupational Therapy Other Electrical Engineering, Electronic Engineering, Information Engineering Control Engineering
Research subject
Physiotherapy; Occupational therapy; Industrial Electronics; Control Engineering
Identifiers
urn:nbn:se:ltu:diva-69826 (URN)10.1177/0145482X19842491 (DOI)2-s2.0-85064590614 (Scopus ID)
Note

Validerad;2019;Nivå 2;2019-05-15 (johcin)

Available from: 2018-06-25 Created: 2018-06-25 Last updated: 2019-05-15Bibliographically approved
Mansouri, S. S., Arranz, M. C., Kanellakis, C. & Nikolakopoulos, G. (2019). Autonomous MAV Navigation in Underground Mines Using Darkness Contours Detection. In: : . Paper presented at 12th International Conference on Computer Vision Systems (ICVS 2019).
Open this publication in new window or tab >>Autonomous MAV Navigation in Underground Mines Using Darkness Contours Detection
2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

This article considers a low-cost and light weight platform for the task of autonomous flying for inspection in underground mine tunnels. The main contribution of this paper is integrating simple, efficient and well-established methods in the computer vision community in a state of the art vision-based system for Micro Aerial Vehicle (MAV) navigation in dark tunnels. These methods include Otsu's threshold and Moore-Neighborhood object tracing. The vision system can detect the position of low-illuminated tunnels in image frame by exploiting the inherent darkness in the longitudinal direction. In the sequel, it is converted from the pixel coordinates to the heading rate command of the MAV for adjusting the heading towards the center of the tunnel. The efficacy of the proposed framework has been evaluated in multiple experimental field trials in an underground mine in Sweden, thus demonstrating the capability of low-cost and resource-constrained aerial vehicles to fly autonomously through tunnel confined spaces.

Keywords
Micro Aerial Vehicles (MAVs), Vision-based Navigation, Autonomous Drift Inspection, Otsu's Theshold, Moore-Neighborhood Tracing
National Category
Control Engineering Other Civil Engineering
Research subject
Control Engineering; Operation and Maintenance
Identifiers
urn:nbn:se:ltu:diva-75270 (URN)
Conference
12th International Conference on Computer Vision Systems (ICVS 2019)
Funder
EU, Horizon 2020, 730302
Available from: 2019-07-09 Created: 2019-07-09 Last updated: 2019-08-13
Koval, A., Mansouri, S. S. & Nikolakopoulos, G. (2019). Online Multi-Agent Based Cooperative Exploration and Coverage in Complex Environment. In: : . Paper presented at The European Control Conference (ECC).
Open this publication in new window or tab >>Online Multi-Agent Based Cooperative Exploration and Coverage in Complex Environment
2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

In this article, an online collaborative exploration and coverage method is proposed for the unknown complex environment with multiple agents. The exploration and coverage is based on Boustrophedon motion, while the detection conditions for backtracking points have been modified based on mission requirements, the battery charge level of each agent is considered to reduce agent loss, and collision free paths are generated. The proposed method is evaluated in simulation, where complex environment with multiple branches is explored by multiple agents.

National Category
Robotics
Identifiers
urn:nbn:se:ltu:diva-73507 (URN)
Conference
The European Control Conference (ECC)
Projects
Swedish Institute VISBY programme
Funder
EU, Horizon 2020, 730302
Available from: 2019-08-12 Created: 2019-08-12 Last updated: 2019-08-12
Kanellakis, C., Mansouri, S. S., Georgoulas, G. & Nikolakopoulos, G. (2019). Towards Autonomous Surveying of Underground Mine using MAVs geogeo. In: : . Paper presented at 27th International Conference on Robotics in Alpe-Adria-Danube Region, Patras, Greece, June 6-8, 2018 (pp. 173-180). Springer, 67
Open this publication in new window or tab >>Towards Autonomous Surveying of Underground Mine using MAVs geogeo
2019 (English)Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

Micro Aerial Vehicles (MAVs) are platforms that received great attention during the last decade. Recently, the mining industry has been considering the usage of aerial autonomous platforms in their processes. This article initially investigates potential application scenarios for this technology in mining. Moreover, one of the main tasks refer to surveillance and maintenance of infrastructure assets. Employing these robots for underground surveillance processes of areas like shafts, tunnels or large voids after blasting, requires among others the development of elaborate navigation modules. This paper proposes a method to assist the navigation capabilities of MAVs in challenging mine environments, like tunnels and vertical shafts. The proposed method considers the use of Potential Fields method, tailored to implement a sense-and-avoid system using a minimal ultrasound-based sensory system. Simulation results demonstrate the effectiveness of the proposed strategy.

Place, publisher, year, edition, pages
Springer, 2019
Series
Mechanisms and Machine Science, ISSN 2211-0984
Keywords
MAV, Underground Mines, Navigation
National Category
Engineering and Technology Control Engineering
Research subject
Control Engineering; Control Engineering
Identifiers
urn:nbn:se:ltu:diva-70113 (URN)10.1007/978-3-030-00232-9_18 (DOI)000465020800018 ()2-s2.0-85054305469 (Scopus ID)
Conference
27th International Conference on Robotics in Alpe-Adria-Danube Region, Patras, Greece, June 6-8, 2018
Available from: 2018-07-12 Created: 2018-07-12 Last updated: 2019-05-02Bibliographically approved
Mansouri, S. S., Karvelis, P., Kanellakis, C., Koval, A. & Nikolakopoulos, G. (2019). Visual Subterranean Junction Recognition for MAVs based on Convolutional Neural Networks. In: : . Paper presented at IEEE 45th Annual Conference of the Industrial Electronics Society (IECON 2019).
Open this publication in new window or tab >>Visual Subterranean Junction Recognition for MAVs based on Convolutional Neural Networks
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2019 (English)Conference paper, Published paper (Refereed)
Abstract [en]

This article proposes a novel visual framework for detecting tunnel crossings/junctions in underground mine areas towards the autonomous navigation of Micro Aeril Vehicles (MAVs). Usually mine environments have complex geometries, including multiple crossings with different tunnels that challenge the autonomous planning of aerial robots. Towards the envisioned scenario of autonomous or semi-autonomous deployment of MAVs with limited Line-of-Sight in subterranean environments, the proposed module acknowledges the existence of junctions by providing crucial information to the autonomy and planning layers of the aerial vehicle. The capability for a junction detection is necessary in the majority of mission scenarios, including unknown area exploration, known area inspection and robot homing missions. The proposed novel method has the ability to feed the image stream from the vehicles’ on-board forward facing camera in a Convolutional Neural Network (CNN) classification architecture, expressed in four categories: 1) left junction, 2) right junction, 3) left & right junction, and 4) no junction in the local vicinity of the vehicle. The core contribution stems for the incorporation of AlexNet in a transfer learning scheme for detecting multiple branches in a subterranean environment. The validity of the proposed method has been validated through multiple data-sets collected from real underground environments, demonstrating the performance and merits of the proposed module.

National Category
Engineering and Technology
Identifiers
urn:nbn:se:ltu:diva-75555 (URN)
Conference
IEEE 45th Annual Conference of the Industrial Electronics Society (IECON 2019)
Available from: 2019-08-16 Created: 2019-08-16 Last updated: 2019-08-16
Mansouri, S. S., Kanellakis, C., Georgoulas, G., Kominiak, D., Gustafsson, T. & Nikolakopoulos, G. (2018). 2D visual area coverage and path planning coupled with camera footprints. Control Engineering Practice, 75, 1-16
Open this publication in new window or tab >>2D visual area coverage and path planning coupled with camera footprints
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2018 (English)In: Control Engineering Practice, ISSN 0967-0661, E-ISSN 1873-6939, Vol. 75, p. 1-16Article in journal (Refereed) Published
Abstract [en]

Unmanned Aerial Vehicles (UAVs) equipped with visual sensors are widely used in area coverage missions. Guaranteeing full coverage coupled with camera footprint is one of the most challenging tasks, thus, in the presented novel approach a coverage path planner for the inspection of 2D areas is established, a 3 Degree of Freedom (DoF) camera movement is considered and the shortest path from the taking off to the landing station is generated, while covering the target area. The proposed scheme requires a priori information about the boundaries of the target area and generates the paths in an offline process. The efficacy and the overall performance of the proposed method has been experimentally evaluated in multiple indoor inspection experiments with convex and non convex areas. Furthermore, the image streams collected during the coverage tasks were post-processed using image stitching for obtaining a single overview of the covered scene.

Place, publisher, year, edition, pages
Elsevier, 2018
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-68057 (URN)10.1016/j.conengprac.2018.03.011 (DOI)000433648100001 ()2-s2.0-85044107984 (Scopus ID)
Projects
Collaborative Aerial Robotic Workers, AEROWORKS
Funder
EU, Horizon 2020, 644128
Note

Validerad;2018;Nivå 2;2018-03-26 (andbra)

Available from: 2018-03-26 Created: 2018-03-26 Last updated: 2018-08-09Bibliographically approved
Fresk, E. & Nikolakopoulos, G. (2018). A generalized Frame Adaptive MPC for the low-level control of UAVs. In: 2018 European Control Conference (ECC): . Paper presented at European Control Conference, Cyprus, Limasson, 12-15 June, 2018 (pp. 1815-1820). Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE)
Open this publication in new window or tab >>A generalized Frame Adaptive MPC for the low-level control of UAVs
2018 (English)In: 2018 European Control Conference (ECC), Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018, p. 1815-1820Conference paper, Published paper (Refereed)
Abstract [en]

The aim of this article is to establish an adaptiveModel Predictive Control (MPC) scheme for the angular rate and thrust control of a multirotor Unmanned Aerial Vehicle (UAV). The proposed model adaptiveness comes from estimating the movement of the Center of Gravity (CoG) combined withthe thrust constant of the motors, making the system robust to disturbances and fast to adapt to changing parameters, while also taking under consideration the control signal bounds in order to guarantee for no motor stalls, while flying. The linear requirements of the MPC are adhered to by transforming the estimation and control problem into a control signal squared domain, making the system linear. The efficacy of the proposed estimation and control scheme is presented in simulations where worst case scenarios have been considered.

Place, publisher, year, edition, pages
Piscataway, NJ: Institute of Electrical and Electronics Engineers (IEEE), 2018
Keywords
UAV; Adaptive Control; System Identification
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-69752 (URN)10.23919/ECC.2018.8550210 (DOI)000467725301136 ()2-s2.0-85059820331 (Scopus ID)978-3-9524-2698-2 (ISBN)978-1-5386-5303-6 (ISBN)
Conference
European Control Conference, Cyprus, Limasson, 12-15 June, 2018
Projects
AEROWORKS (Grant Agreement No. 644128)SIMS (Grant Agreement No. 730302)
Available from: 2018-06-21 Created: 2018-06-21 Last updated: 2019-06-18Bibliographically approved
Zachiotis, G., Andrikopoulos, G., Gornez, R., Nakamura, K. & Nikolakopoulos, G. (2018). A Survey on the Application Trends of Home Service Robotics. In: 2018 IEEE International Conference on Robotics and Biomimetics (ROBIO): . Paper presented at 2018 IEEE International Conference on Robotics and Biomimetics (ROBIO), Kuala Lumpur, Malaysia, 12-15 december 2018 (pp. 1999-2006). IEEE
Open this publication in new window or tab >>A Survey on the Application Trends of Home Service Robotics
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2018 (English)In: 2018 IEEE International Conference on Robotics and Biomimetics (ROBIO), IEEE, 2018, p. 1999-2006Conference paper, Published paper (Refereed)
Abstract [en]

The area of service robots has steadily gained interest over the years as an attempt for deploying robots to tackle problems faced in our everyday lives. In this article, a survey on the application areas of home service robots is presented. A collection of robotic appliances is selected to be introduced based on their application objective of being an active part in a home environment. The dominant application areas of robotic home service are identified and overviewed through the governing dipole of: a) consumer, and b) research. The functional capabilities of each robot are addressed from a design and specification point of view, in order to highlight their key enabling features and justify their inclusion to each application area.

Place, publisher, year, edition, pages
IEEE, 2018
Keywords
Speech recognition, Face recognition, Robot sensing systems, Service robots, Emotion recognition, Navigation
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-73554 (URN)10.1109/ROBIO.2018.8665127 (DOI)
Conference
2018 IEEE International Conference on Robotics and Biomimetics (ROBIO), Kuala Lumpur, Malaysia, 12-15 december 2018
Available from: 2019-04-11 Created: 2019-04-11 Last updated: 2019-04-11Bibliographically approved
Kostopoulos, V., Psarras, S., Loutas, T., Sotiriadis, G., Gray, I., Padiyar, M., . . . Nikolakopoulos, G. (2018). Autonomous Inspection and Repair of Aircraft Composite Structures. In: P. Kopacek; B. Ibrahimov (Ed.), 18th IFAC Conference on Technology, Culture and International Stability TECIS 2018: . Paper presented at 18th International-Federation-of-Automatic-Control (IFAC) Conference on Technology, Culture and International Stability (TECIS), September 13-15, 2018, Baku, AZERBAIJAN. (pp. 554-557). Elsevier, 51
Open this publication in new window or tab >>Autonomous Inspection and Repair of Aircraft Composite Structures
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2018 (English)In: 18th IFAC Conference on Technology, Culture and International Stability TECIS 2018 / [ed] P. Kopacek; B. Ibrahimov, Elsevier, 2018, Vol. 51, p. 554-557Conference paper, Published paper (Refereed)
Abstract [en]

This paper deals with the development of an innovative approach for inspection and repair of damage in aeronautical composites that took place in the first two years of the H2020 Compinnova project which. The aim is a newly designed robotic platform for autonomous inspection using combined infrared thermography (IRT) and phased array (PA) non-destructive investigation for damage detection and characterization, while integrated with laser repaircapabilities. This will affect the increasing societal need for safer aircraft in the lowest possible cost, while new and effective techniques of inspection are needed because of the rapidly expanding use of composites in the aerospace industry.

Place, publisher, year, edition, pages
Elsevier, 2018
Series
IFAC-PapersOnLine, ISSN 2405-8963 ; 30
National Category
Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-72318 (URN)10.1016/j.ifacol.2018.11.267 (DOI)000451096700105 ()2-s2.0-85057019527 (Scopus ID)
Conference
18th International-Federation-of-Automatic-Control (IFAC) Conference on Technology, Culture and International Stability (TECIS), September 13-15, 2018, Baku, AZERBAIJAN.
Available from: 2018-12-18 Created: 2018-12-18 Last updated: 2018-12-18Bibliographically approved
Kanellakis, C., Mansouri, S. S., Fresk, E., Kominiak, D. & Nikolakopoulos, G. (2018). Cooperative UAVs as a Tool for Aerial Inspection of Large Scale Aging Infrastructure. In: 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS): . Paper presented at 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS),Madrid, Spain,1-5 Oct. 2018 (pp. 5040-5040). Piscataway, NJ: IEEE
Open this publication in new window or tab >>Cooperative UAVs as a Tool for Aerial Inspection of Large Scale Aging Infrastructure
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2018 (English)In: 2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), Piscataway, NJ: IEEE, 2018, p. 5040-5040Conference paper, Oral presentation with published abstract (Refereed)
Abstract [en]

This work presents an aerial tool towards the autonomous cooperative coverage and inspection of a large scale 3D infrastructure using multiple Unmanned Aerial Vehicles (UAVs). In the presented approach the UAVs are relying only on their onboard computer and sensory system, deployed for inspection of the 3D structure. In this application each agent covers a different part of the scene autonomously, while avoiding collisions. The autonomous navigation of each platform on the designed path is enabled by the localization system that fuses Ultra Wideband with inertial measurements through an Error- State Kalman Filter. The visual information collected from the aerial team is collaboratively processed to create the 3D model. The performance of the overall setup has been experimentally evaluated in realistic wind turbine inspection experiments, providing dense 3D reconstruction of the inspected structures.

Place, publisher, year, edition, pages
Piscataway, NJ: IEEE, 2018
Series
IEEE International Conference on Intelligent Robots and Systems, ISSN 2153-0858, E-ISSN 2153-0866
National Category
Robotics Control Engineering
Research subject
Control Engineering
Identifiers
urn:nbn:se:ltu:diva-72850 (URN)10.1109/IROS.2018.8593996 (DOI)000458872704097 ()978-1-5386-8095-7 (ISBN)978-1-5386-8094-0 (ISBN)978-1-5386-8093-3 (ISBN)
Conference
2018 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS),Madrid, Spain,1-5 Oct. 2018
Funder
EU, Horizon 2020
Note

abstarct + video

Available from: 2019-02-12 Created: 2019-02-12 Last updated: 2019-03-27Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-0126-1897

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