| 1. |
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| 2. |
- Andrikopoulos, Georgios, et al.
(författare)
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Adaptive internal model control scheme for a pneumatic artificial muscle
- 2013
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Ingår i: European Control Conference (ECC), July 17-19, Zurich, Switzerland 2013. - : IEEE. - 9783952417348 ; , s. 772-777
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Konferensbidrag (refereegranskat)abstract
- The Pneumatic Artificial Muscle (PAM) is a highly non-linear form of actuation that is characterized by a decrease in the actuating length when pressurized. Its nonlinear nature and time-varying parameters cause difficulties in modeling their characteristics and designing controllers for high-performance positioning systems. In this article, the model identification and control problem of a PAM is being considered. The identification of the PAM’s model parameters is being carried out by a Recursive Least Square (RLS) based algorithm, while an Internal Model Control (IMC) structure is being synthesized. Experimental studies are being utilized to prove the overall efficiency of the suggested control scheme, regarding: a) set-point tracking performance through selected positioning scenarios, b) robustness through disturbance cancellation, and c) adaptability through hysteresis shift compensation.
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| 3. |
- Andrikopoulos, Georgios, et al.
(författare)
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Design, development and control of a human-inspired two-arm robot via Pneumatic Artificial Muscles
- 2017
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Ingår i: 2017 25th Mediterranean Conference on Control and Automation, MED 2017. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509045334 ; , s. 241-246
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Konferensbidrag (refereegranskat)abstract
- In this article, the design and implementation of a 10 Degree-of-Freedom (DoF) human-inspired two-arm robot is presented. Multiple Pneumatic Artificial Muscles (PAMs) in antagonistic formations are incorporated for undertaking the two arms' movements, while the design goal is the replication of human-like motion patterns, described by smoothness, inherent compliance and accuracy. To evaluate the feasibility of the proposed concept, the 10-DoF robot is developed and experimentally tested in open and closed-loop control scenarios via the use of a multiple Advanced Nonlinear PID (ANPID) based scheme.
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| 4. |
- Andrikopoulos, Georgios, et al.
(författare)
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Dynamic analysis and cascade movement simulation of a pneumatic muscle actuator
- 2011
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Ingår i: Proceedings of the IASTED International Conference on Modelling, Simulation and Identification. - : ACTA Press. - 9780889869042 ; , s. 407-414
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Konferensbidrag (refereegranskat)abstract
- The aim of this article is to present a dynamic analysis and a cascade movement simulation of a Pneumatic Muscle Actuator (PMA). PMAs are highly non–linear pneumatic actuators where their elongation are proportional to the interval pressure. Their non–linear characteristics and the property of the hysteresis are posing several difficulties in simulating these pneumatic actuators and to obtain a comprehension of the PMA’s physical movement. In this article a novel detailed modeling, based on hardware in the loop simulationstudies, capable to describe the dynamic characteristic of the PMA and a detailed simulation environment for studying the cascade movement of PMAs will be presented.
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| 5. |
- Andrikopoulos, George, et al.
(författare)
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HUmanoid Robotic Leg via pneumatic muscle actuators : implementation and control
- 2018
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Ingår i: Meccanica (Milano. Print). - : Springer. - 0025-6455 .- 1572-9648. ; 53:1-2, s. 465-480
-
Tidskriftsartikel (refereegranskat)abstract
- In this article, a HUmanoid Robotic Leg (HURL) via the utilization of pneumatic muscle actuators (PMAs) is presented. PMAs are a pneumatic form of actuation possessing crucial attributes for the implementation of a design that mimics the motion characteristics of a human ankle. HURL acts as a feasibility study in the conceptual goal of developing a 10 degree-of-freedom (DoF) lower-limb humanoid for compliance and postural control, while serving as a knowledge basis for its future alternative use in prosthetic robotics. HURL’s design properties are described in detail, while its 2-DoF motion capabilities (dorsiflexion–plantar flexion, eversion–inversion) are experimentally evaluated via an advanced nonlinear PID-based control algorithm.
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| 6. |
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| 7. |
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| 8. |
- Andrikopoulos, George, Dr. 1986-, et al.
(författare)
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On Model-based Adhesion Control of a Vortex Climbing Robot
- 2019
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Ingår i: 2019 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). - : IEEE. - 9781728140049 ; , s. 1460-1465
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this article, the adhesion modeling and control case of a Vortex Climbing Robot (VCR) is investigated against a surface of variable orientations. The critical adhesion force exerted from the implemented Vortex Actuator (VA) and the VCR's achievable payload are analyzed under 3-DOF rotations of the test surface, while extracted from both geometrical analysis and dynamically-simulated numerical results. A model-based control scheme is later proposed, with the goal of achieving adhesion while the VCR remains immobilized, limiting the power consumption and compensating for disturbances (e.g. moving cables) leading to Center-of-Mass (CoM) changes. Finally, the model-based control scheme is experimentally evaluated, with the VCR prototype on a rotating and moving flat surface. The presented results support the use of the proposed methodology in climbing robots targeting inspection and maintenance of stationary surfaces (flat, curved etc.), as well as future robotic solutions operating on moving structures (e.g. ships, cranes, folding bridges).
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| 9. |
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| 10. |
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| 11. |
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| 12. |
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| 13. |
- Brusell, Angelica, et al.
(författare)
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Novel considerations on the negative pressure adhesion of electric ducted fans : An experimental study
- 2017
-
Ingår i: 2017 25th Mediterranean Conference on Control and Automation, MED 2017. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509045334 ; , s. 1404-1409
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Konferensbidrag (refereegranskat)abstract
- In this article, the potential of utilizing an Electric Ducted Fan (EDF) as an adhesion actuator is investigated in detail, where an experimental setup is implemented for evaluating the EDF's ability to adhere to a test surface through negative pressure generation. Different design variables and modifications to the original EDF structure are tested, while their impact on the adhesion efficiency is experimentally evaluated. The presented investigation acts as a preliminary study to the goal of incorporating the resulting optimized negative pressure-based actuation method in a wall-climbing robot for inspection of aircraft fuselages
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| 14. |
- Elbadawi, Mohammed, 1987-, et al.
(författare)
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Bio-Inspired Climbing Robots in Wet Environments : Recent Trends in Adhesion Methods and Materials
- 2018
-
Ingår i: IEEE ROBIO 2018. - : IEEE. ; , s. 2347-2353
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Konferensbidrag (refereegranskat)abstract
- In the case of Wall Climbing Robot (WCR) design, nature has always been one of the biggest inspirations. While WCR designs have been incorporating adhesion techniques inspired by organisms, including reptiles, insects, amphibians and marine invertebrates, most efforts have been focusing mainly on adhesion for dry surfaces. For WCRs to become widely applicable under all environments, given the vast areas of this planet described by high precipitation, the ability to scale vertical surfaces in wet conditions should be considered a design necessity. To this goal, this article focuses on the most commonly adopted adhesion mechanisms, while providing an overview on recent WCR technological advances through the prism of wet adhesion. An extensive outlook is also detailed, including promising research directions yet to be trialed in bio-inspirations and recent material developments, which could further bridge the gap between WCR design and wet adhesion towards all-environment climbing robots.
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| 15. |
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| 16. |
- Eleftheroglou, Nick, et al.
(författare)
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Intelligent data-driven prognostic methodologies for the real-time remaining useful life until the end-of-discharge estimation of the Lithium-Polymer batteries of unmanned aerial vehicles with uncertainty quantification
- 2019
-
Ingår i: Applied Energy. - : Elsevier. - 0306-2619 .- 1872-9118. ; 254
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, the discharge voltage is utilized as a critical indicator towards the probabilistic estimation of the Remaining Useful Life until the End-of-Discharge of the Lithium-Polymer batteries of unmanned aerial vehicles. Several discharge voltage histories obtained during actual flights constitute the in-house developed training dataset. Three data-driven prognostic methodologies are presented based on state-of-the-art as well as innovative mathematical models i.e. Gradient Boosted Trees, Bayesian Neural Networks and Non-Homogeneous Hidden Semi Markov Models. The training and testing process of all models is described in detail. Remaining Useful Life prognostics in unseen data are obtained from all three methodologies. Beyond the mean estimates, the uncertainty associated with the point predictions is quantified and upper/lower confidence bounds are also provided. The Remaining Useful Life prognostics during six random flights starting from fully charged batteries are presented, discussed and the pros and cons of each methodology are highlighted. Several special metrics are utilized to assess the performance of the prognostic algorithms and conclusions are drawn regarding their prognostic capabilities and potential.
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| 17. |
- Eleftheroglou, Nick, et al.
(författare)
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Real time Diagnostics and Prognostics of UAV Lithium-Polymer Batteries
- 2019
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Ingår i: Proceedings of the Annual Conference of the Prognostics and Health Management Society 2019. - : Prognostics and Health Management Society.
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This paper examines diagnostics and prognostics of Lithium-Polymer (Li-Po) batteries for unmanned aerial vehicles (UAVs). Several discharge voltage histories obtained during actual indoor flights constitute the training data for a data-driven approach, utilizing the Non-Homogenous Hidden Semi Markov model (NHHSMM). NHHSMM is a suitable candidate as it has a rich mathematical structure, which is capable of describing the discharge process of Li-Po batteries and providing diagnostic and prognostic measures. Diagnostics and prognostics in unseen data are obtained and compared with the actual remaining flight time in order to validate the effectiveness of the selected model.
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| 18. |
- Gavrilis, Dimitris, et al.
(författare)
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A One-Class Approach to Cardiotocogram Assessment
- 2015
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Ingår i: 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society. - Piscataway, NJ : IEEE Communications Society. - 9781424492718 ; , s. 518-521
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Konferensbidrag (refereegranskat)abstract
- Cardiotocogram (CTG) is the most widely used means for the assessment of fetal condition. CTG consists of two traces one depicting the Fetal Heart Rate (FHR), and the other the Uterine Contractions (UC) activity. Many automatic methods have been proposed for the interpretation of the CTG. Most of them rely either on a binary classification approach or on a multiclass approach to come up with a decision about the class that the tracing belongs to. This work investigates the use of a one-class approach to the assessment of CTGs building a model only for the healthy data. The preliminary results are promising indicating that normal traces could be used as part of an automatic system that can detect deviations from normality.
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| 19. |
- Georgoulas, George, et al.
(författare)
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A Data Fusion Approach to Bearing Fault Detection and Diagnosis
- 2015
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Ingår i: IEEE International Conference on Power Engineering, Energy and Electrical Drives, POWERENG 2015, May 11-13, Riga, Latvia, 2015. - Piscataway, NJ : IEEE Communications Society. ; , s. 109-113
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Konferensbidrag (refereegranskat)abstract
- This paper presents a data fusion approach for the diagnosis of bearing faults under different seeded fault scenarios. The approach is based on the extraction of three simple and intuitive features that fuse the information that comes from two accelerometers placed at two different sites of the test bed. The analysis shows that in the case of the occurrence of a fault even in an early stage the “footprint” left at the scatter plot of the measurements coming from the two accelerometers can effectively turned into features/descriptors by simple statistical measures such as the elements of the covariance matrix. Those features when fed to a k-nearest neighbor classifier or an ensemble of one class detectors can lead to a remarkably high detection/diagnostic performance.
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| 20. |
- Georgoulas, George, et al.
(författare)
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An exploratory approach to fetal heart rate–pH-based systems
- 2021
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Ingår i: Signal, Image and Video Processing. - : Springer. - 1863-1703 .- 1863-1711. ; 15:1, s. 43-51
-
Tidskriftsartikel (refereegranskat)abstract
- This paper presents an exploratory approach of the fetal heart rate (FHR) analysis, aiming to highlight potential limitations of the current predictive modeling attempts. To do so, a set of features that are usually encountered in FHR analysis as well as features extracted using a variant of symbolic aggregate approximation were projected onto a lower-dimensional space where patterns can easily be discerned. The results show, both in a qualitative and a quantitative manner, that there is high overlap between the classes that are formed using solely the umbilical cord pH information, irrespective of the selected dimensionality reduction method. These findings suggest that there is probably a limit to the performance expectation of the current pH-based systems and that alternative approaches should be also pursued to enhance the utility of computer-based decision support technologies.
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| 21. |
- Georgoulas, George, et al.
(författare)
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Automatizing the detection of rotor failures in induction motors operated via soft-starters
- 2016
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Ingår i: Annual Conference of the IEEE Industrial Electronics Society, IECON 2015. - Piscataway, NJ : IEEE Communications Society. - 9781479917624 ; , s. 3743-3748
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Konferensbidrag (refereegranskat)abstract
- Implementation of unsupervised induction motor condition monitoring systems has drawn an increasing attention recently among motor drives manufacturers. In the case of soft- starters the possibility of incorporating fault detection features to their conventional functions provides an added value to those elements. Design and development of advanced algorithms that are able to automatically detect and alert about possible failures without requiring continuous human inspection is an especially challenging research goal. In this paper, an algorithm for the automatic detection of rotor damages in induction motors in the case of soft starting is proposed. The twofold approach relies, first, on the application of a time-frequency transform to the starting current signal and, second, on a pattern recognition stage based on the treatment of the time-frequency representation as a symbolic sequence. The innovation of this work is the implementation of the proposed approach for the automatic detection of rotor cage faults in soft-started motors. The experimental results prove the usefulness of the approach for the automatic detection of such faults and its potential for possible future implementation in soft-started machines.
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| 22. |
- Georgoulas, George, et al.
(författare)
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Principal component analysis of the start-up transient and hidden Markov modeling for broken rotor bar fault diagnosis in asynchronous machines
- 2013
-
Ingår i: Expert systems with applications. - : Elsevier BV. - 0957-4174 .- 1873-6793. ; 40:17, s. 7024-7033
-
Tidskriftsartikel (refereegranskat)abstract
- This article presents a novel computational method for the diagnosis of broken rotor bars in three phase asynchronous machines. The proposed method is based on Principal Component Analysis (PCA) and is applied to the stator’s three phase start-up current. The fault detection is easier in the start-up transient because of the increased current in the rotor circuit, which amplifies the effects of the fault in the stator’s current independently of the motor’s load. In the proposed fault detection methodology, PCA is initially utilized to extract a characteristic component, which reflects the rotor asymmetry caused by the broken bars. This component can be subsequently processed using Hidden Markov Models (HMMs). Two schemes, a multiclass and a one-class approach are proposed. The efficiency of the novel proposed schemes is evaluated by multiple experimental test cases. The results obtained indicate that the suggested approaches based on the combination of PCA and HMM, can be successfully utilized not only for identifying the presence of a broken bar but also for estimating the severity (number of broken bars) of the fault.
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| 23. |
- Herceg, Domagoj, et al.
(författare)
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Data-driven Modelling, Learning and Stochastic Predictive Control for the Steel Industry
- 2017
-
Ingår i: 2017 25th Mediterranean Conference on Control and Automation, MED 2017. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509045334 ; , s. 1361-1366
-
Konferensbidrag (refereegranskat)abstract
- The steel industry involves energy-intensive processessuch as combustion processes whose accurate modellingvia first principles is both challenging and unlikely to leadto accurate models let alone cast time-varying dynamics anddescribe the inevitable wear and tear. In this paper we addressthe main objective which is the reduction of energy consumptionand emissions along with the enhancement of the autonomy ofthe controlled process by online modelling and uncertaintyawarepredictive control. We propose a risk-sensitive modelselection procedure which makes use of the modern theoryof risk measures and obtain dynamical models using processdata from our experimental setting: a walking beam furnaceat Swerea MEFOS. We use a scenario-based model predictivecontroller to track given temperature references at the threeheating zones of the furnace and we train a classifier whichpredicts possible drops in the excess of Oxygen in each heatingzone below acceptable levels. This information is then used torecalibrate the controller in order to maintain a high qualityof combustion, therefore, higher thermal efficiency and loweremissions
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| 24. |
- Kanellakis, Christoforos, et al.
(författare)
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Towards Autonomous Surveying of Underground Mine using MAVs
- 2019
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 25. |
- Karvelis, Petros, et al.
(författare)
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A Laser Dot Tracking Method for the Assessment of Sensorimotor Function of the Hand
- 2017
-
Ingår i: 2017 25th Mediterranean Conference on Control and Automation, MED 2017. - Piscataway. NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781509045334 ; , s. 217-222
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Konferensbidrag (refereegranskat)abstract
- Assessment of sensorimotor function is crucial during the rehabilitation process of various physical disorders, including impairments of the hand. While moment performance can be accurately assessed in movement science laboratories involving highly specialized personnel and facilities there is a lack of feasible objective methods for the general clinic. This paper describes a novel approach to sensorimotor assessment using an intuitive test and a specifically tailored image processing pipeline for the quantification of the test. More specifically the test relies on the patient being instructed on following a zig-zag pattern using a handled laser pointer. The movement of the pointer is tracked using image processing algorithm capable of automating the whole procedure. The method has potential for feasible objective clinical assessment of the hand and other body parts
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| 26. |
- Karvelis, Petros, et al.
(författare)
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Symbolic time series analysis of the soft starting transient in induction machines
- 2015
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Ingår i: 2015 IEEE International Conference on Industrial Technology (ICIT 2015) to be held in Seville, Spain, March 17-19, 2015.. - Piscataway, NJ : IEEE Communications Society. - 9781479978007 ; , s. 3243-3248
-
Konferensbidrag (refereegranskat)abstract
- Induction motors are in the heart of almost every production line especially due to their robustness under harsh environments. Nevertheless, even induction machines are prone to faults. Among them, the faults related to the breakage of rotor bars have received special attention by the research community with a number of methods proposed both for the case of steady state as well as for transient operation. For the latter, methods relying on the analysis of the start-up transient have proven to be able to effectively isolate the faulty component that is created by the asymmetry caused by the bar breakage. However, very little work has been done concerning the soft starting of induction machines. In this work, preliminary results of the application of a symbolic time series technique for the analysis of the transient, when the motor is controlled by a soft starter, will be presented and experimentally evaluated.
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| 27. |
- Mansouri, Sina Sharif, et al.
(författare)
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Towards MAV Navigation in Underground Mine Using Deep Learning
- 2018
-
Ingår i: IEEE ROBIO 2018. - : IEEE. ; , s. 880-885
-
Konferensbidrag (refereegranskat)abstract
- The usage of Micro Aerial Vehicles (MAVs) is rapidly emerging in the mining industry to increase overall safety and productivity. However, the mine environment is especially challenging for the MAV's operation due to the lack of illumination, narrow passages, wind gusts, dust, and other factors that can affect the MAV's overall flying capability. This article presents a method to assist the navigation of MAVs by using a method from the field of Deep Learning (DL), while considering a low-cost platform without high-end sensor suits. The presented DL scheme can be further utilized as a supervised image classifier that has the ability to process the image frames from a single on-board camera and to provide mine tunnel wall collision prevention. The efficiency of the proposed scheme has been experimentally evaluated in two underground tunnel environments that were used for data collection, training, and corresponding testing under multiple flying scenarios with different cameras configurations and illuminations.
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| 28. |
- Mustafa, Mohammed Obaid, et al.
(författare)
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Bearing fault classification based on minimum volume ellipsoid feature extraction
- 2013
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Ingår i: 2013 IEEE Multiconference on Systems and Control (MSC), Hyderabad, India, August, 28-30, 2013. ; , s. 1177-1182
-
Konferensbidrag (refereegranskat)abstract
- This article presents a novel fault classification and diagnosis technique for bearings based on a Minimum Volume Ellipsoid (MVE) method for feature extraction. Data from two accelerometers located at two different sights of the test bed are combined to create a two dimensional representation and the feature extraction stage condenses that information using an ellipsoid description. The proposed features feed a simple non-linear classifier which separates almost perfectly between normal and faulty conditions, with also very high diagnostic accuracy between the faulty classes. The obtained results suggest that this novel representation can be used within a condition monitoring system.
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| 29. |
- Mustafa, Mohammed Obaid, et al.
(författare)
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Fault classification of Broken Rotor Bars in Induction Motors Based on Envelope Current Analysis
- 2015
-
Ingår i: IEEE 13th International Conference on Industrial Informatics (INDIN), 2015. - Piscataway, NJ : IEEE Communications Society. - 9781479966493 ; , s. 795-800
-
Konferensbidrag (refereegranskat)abstract
- In this article a method for the fault classification of one, two, and three broken bars in induction motors under full load condition is presented. The proposed methodology is based on the current envelope analysis, which in the past has been also widely utilized in analyzing the rotor faults at low slips. As it will be presented, the information obtained from the envelope current is valuable in manifesting and validating the presence of fault, since the current envelope and its characteristics often contains important information about the existence of a fault and the corresponding fault type. The proposed method mainly focuses on the case of steady-state operation under full load. In the established fault detection scheme, from the stator’s current six statistical features are extracted and utilized for the fault detection and classification. In more detail, three classifiers, a linear, a quadratic and a Nearest Neighbor have been investigated for the diagnosis of broken rotor bar faults of an induction motor. The presented approach have manifested promising results using experimental data.
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| 30. |
- Mustafa, Mohammed Obaid, et al.
(författare)
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Principal Component Analysis Anomaly Detector for Rotor Broken Bars
- 2015
-
Ingår i: IECON 2014. - Piscataway, NJ : IEEE Communications Society. - 9781479940332 ; , s. 3462-3467
-
Konferensbidrag (refereegranskat)abstract
- In this article a method for the detection of broken rotor bars in asynchronous machines operating under full load is presented. Unlike most Motor Current Signature Analysis (MCSA) approaches, which operate in the frequency domain, our method operates in the time domain. The scheme is based on the use of a Principal Component Analysis (PCA) fault/anomaly detector applied on the three stator currents to calculate the Q statistic which is employed for detecting a fault. The efficiency of the proposed scheme was experimentally evaluated using different fault severity levels, ranging from 1/4 of a broken bar to three broken bars. The obtained results indicate that the method can detect the caused asymmetry with a very restricted amount of data.
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| 31. |
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| 32. |
- Papadimitriou, Andreas, et al.
(författare)
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Design, Development and Experimental Evaluation of a Thrust Vectoring Vortex Climbing Robot
- 2018
-
Ingår i: IEEE ROBIO 2018. - : IEEE. ; , s. 1341-1346
-
Konferensbidrag (refereegranskat)abstract
- In this article, a novel Thrust Vectoring Vortex Climbing Robot (TVV-CR) will be presented from a design development and experimental evaluation perspective. To the goal of providing an efficient and robust climbing robot design, with minimized weight and high permissible payload, a novel Electric Ducted Fan (EDF)-based actuation design is proposed for achieving simultaneous locomotion and adhesion via a controllable tilt mechanism, while excluding the need for active motorized wheels. Towards the development of the TVV-CR, the design and development stages will be presented in detail, while proposing a P-PI-based cascaded control structure for evaluating its overall properties. The efficiency of the suggested scheme will be evaluated by multiple experimental results indicating the robot's ability to follow randomly generated paths, while maintaining its adhesion under different surface inclinations.
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| 33. |
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| 34. |
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| 35. |
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| 36. |
- Papadimitriou, Andreas, et al.
(författare)
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On Path Following Evaluation for a Tethered Climbing Robot
- 2020
-
Ingår i: Proceedings. - : IEEE. ; , s. 656-661
-
Konferensbidrag (refereegranskat)abstract
- Over the last years, there is a growing need for climbing robots performing autonomous inspection tasks of large-scale infrastructure, to reduce inspection time and the overall operation costs. Thickness measurement, visual inspection, fault detection, etc. are a few examples of inspection and maintenance applications that could be performed autonomously by robotic platforms like climbing robots. One of the main challenges of inspecting large infrastructures, is the problem of path planning, as the path should be optimal to reduce the inspection time, incorporate sensor properties, and account for important robot requirements such as power supply cabling. This article proposes a novel path planner targeting inspection tasks, where the restrictions posed by the cabling on a Vortex Robot (VR), the attached sensor, and the properties of the scanned surfaces are taken into consideration. The presented framework is successfully evaluated in multiple closed-loop experiments, under different surface inclinations and VR orientations to demonstrate the efficacy of the path planning and control scheme.
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| 37. |
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| 38. |
- Vachtsevanos, George, et al.
(författare)
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Fault Diagnosis, Failure Prognosis and Fault Tolerant Control of Aerospace/Unmanned Aerial Systems
- 2016
-
Ingår i: 24th Mediterranean Conference on Control and Automation (MED). - Piscataway, NJ : IEEE Communications Society. - 9781467383455 ; , s. 366-371
-
Konferensbidrag (refereegranskat)abstract
- Fault-tolerant control and operation of complex unmanned and aircraft systems is an emerging technology intended to provide the designer and operator with flexibility, interoperability, sustainment and reliability under changing operational requirements or mission profiles. Moreover, it is intended to reconfigure online hardware and software to maintain the operational integrity of the system in the event of contingencies (fault/failure modes). This paper presents an hierarchical architecture that uses available sensor information, fault isolation, failure prognosis, system restructuring and controller reconfiguration. The fault tolerant control framework relies on prognostic information to reconfigure system components and preserve the operational integrity of the aircraft. The hierarchical structure starts at the lowest component level and migrates to the middle system/subsystem level ending with the final mission level. We illustrate the methodology using an electro-mechanical actuator (EMA).
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| 39. |
- Zachiotis, Georgios A., et al.
(författare)
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A Survey on the Application Trends of Home Service Robotics
- 2018
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Ingår i: Proceedings 2018 IEEE International Conference on Robotics and Biomimetics (ROBIO). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- 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.
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| 40. |
- Adaldo, Antonio, et al.
(författare)
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Cooperative coverage for surveillance of 3D structures
- 2017
-
Ingår i: IEEE International Conference on Intelligent Robots and Systems. - Piscataway, NJ : Institute of Electrical and Electronics Engineers (IEEE). - 9781538626825 ; , s. 1838-1845
-
Konferensbidrag (refereegranskat)abstract
- In this article, we propose a planning algorithm for coverage of complex structures with a network of robotic sensing agents, with multi-robot surveillance missions as our main motivating application. The sensors are deployed to monitor the external surface of a 3D structure. The algorithm controls the motion of each sensor so that a measure of the collective coverage attained by the network is nondecreasing, while the sensors converge to an equilibrium configuration. A modified version of the algorithm is also provided to introduce collision avoidance properties. The effectiveness of the algorithm is demonstrated in a simulation and validated experimentally by executing the planned paths on an aerial robot.
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| 41. |
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| 42. |
- Alexhs, Kostas, et al.
(författare)
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Autonomous quadrotor position and attitude PID/PIDD control in GPS-denied environments
- 2011
-
Ingår i: International Review of Automatic Control. - 1974-6059 .- 1974-6067. ; 4:3
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Tidskriftsartikel (refereegranskat)abstract
- This article addresses the control problem of an unmanned quadrotor in the absence of absolute position measurement data (e.g. GPS, external cameras). Based on an attached Inertia Measurement Unit, a sonar and an optic flow sensor, the quadrotor’s translational and rotational motion-vector is estimated using sensor fusion algorithms. A control scheme consisted of three Proportional-Integral-Derivative (PID) controllers for the translational motions, combined with three Proportional-Integral-Derivative-second Derivative (PIDD) controllers for the attitude dynamics is utilized in order to achieve accurate position hold and attitude tracking. The controller is implemented on a quadrotor prototype in indoor position hold experiments and aggressive attitude regulation maneuvers.
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| 43. |
- Alexis, Kostas, et al.
(författare)
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Experimental Constrained Optimal Attitude Control of a Quadrotor subject to Wind Disturbances
- 2014
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Ingår i: International Journal of Control, Automation and Systems. - : Springer Science and Business Media LLC. - 1598-6446 .- 2005-4092. ; 12:6, s. 1289-1302
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Tidskriftsartikel (refereegranskat)abstract
- The design and experimental verification of a Constrained Finite Time Optimal Controller (CFTOC) for attitude maneuvers of an Unmanned Quadrotor operating under severe wind conditions is the subject of this article. The quadrotor’s nonlinear dynamics are linearized in various operating points resulting in a set of piecewise affine models. The CFTO–controller is designed for set-point maneuvers taking into account the switching between the linear models and the state and actuation constraints. The control scheme is applied on experimental studies on a prototype quadrotor operating both in absence and under presence of forcible atmospheric disturbances. Extended experimental results indicate that the proposed control approach attenuates the effects of induced wind–gusts while performing accurate attitude set–point maneuvers.
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| 44. |
- Alexis, Kostas, et al.
(författare)
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Model predictive quadrotor control: attitude, altitude and position experimental studies
- 2012
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Ingår i: IET Control Theory & Applications. - : Institution of Engineering and Technology (IET). - 1751-8644 .- 1751-8652. ; 6:12, s. 1812-1827
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Tidskriftsartikel (refereegranskat)abstract
- This article addresses the control problem of an unmanned quadrotor in an indoor environment where there is lack of absolute localization data. Based on an attached Inertia Measurement Unit, a sonar and an optic flow sensor, the state vector is estimated using sensor fusion algorithms. A novel Switching Model Predictive Controller is designed in order to achieve precise trajectory control, under the presence of forcible wind–gusts. The quadrotor’s attitude, altitude and horizontal linearized dynamics result in a set of Piecewise Affine models, enabling the controller to account for a larger part of the quadrotor’s flight envelope while modeling the effects of atmospheric disturbances as additive–affine terms in the system. The proposed controller algorithm accounts for the state and actuation constraints of the system. The controller is implemented on a quadrotor prototype in indoor position tracking, hovering and attitude maneuvers experiments. The experimental results indicate the overall system’s efficiency in position/altitude/attitude set–point maneuvers.
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| 45. |
- Alexis, Kostas, et al.
(författare)
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Model predictive quadrotor indoor position control
- 2011
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Ingår i: 19th Mediterranean Conference on Control & Automation (MED 2011). - Piscataway, NJ : IEEE Communications Society.
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Konferensbidrag (refereegranskat)abstract
- This article addresses the control problem of quadrotors in environments where absolute-localization data (GPS, positioning from external cameras) is inadequate. Based on an attached IMU and an optical flow sensor the quadrotor’s translational velocity is estimated using an Extended Kalman Filter. Subject to the velocity measurements, the roll, pitch and yaw (RPY) angles, the angular rates and the translational accelerations a switching Model Predictive Controller is designed. The quadrotor dynamics is linearized at various operating points according to the angular rates and the RP angles. The switching is inferred according to the various linearized models of the quadrotor. The controller is applied on a quadrotor prototype in low-altitude position hold maneuvers at very constrained environments. The experimental results indicate the overall system’s efficiency in position/altitude set–point maneuvers.
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| 46. |
- Alexis, Kostas, et al.
(författare)
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On trajectory tracking model predictive control of an unmanned quadrotor helicopter subject to aerodynamic disturbances
- 2014
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Ingår i: Asian Journal of Control. - : Wiley. - 1561-8625 .- 1934-6093. ; 16:1, s. 209-224
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Tidskriftsartikel (refereegranskat)abstract
- In this article a Model Predictive Control (MPC) strategy for the trajectory tracking of an unmanned quadrotor helicopter is presented. The quadrotor’s dynamics are modeled by a set of Piecewise Affine (PWA) systems around different operating points of the translational and rotational motions. The proposed control scheme is dual and is consisted by an integral MPC for the translational motions, followed by a MPC–scheme for the quadrotor’sattitude motions’ tracking. By the utilization of PWA representations, the controller is computed for a larger part of the quadrotor’s flight envelope. Theproposed dual control scheme is able to calculate optimal control actions with robustness against atmospheric disturbances (e.g. wind gusts) and physical constraints of the quadrotor (e.g. maximum lifting forces or fixed thrust limitations in order to extend flight endurance). Extended simulation studies prove the efficiency of the MPC–scheme, both in trajectory tracking and aerodynamic disturbances attenuation.
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| 47. |
- Alexis, Kostas, et al.
(författare)
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Switching model predictive attitude control for a quadrotor helicopter subject to atmospheric disturbances
- 2011
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Ingår i: Control Engineering Practice. - : Elsevier BV. - 0967-0661 .- 1873-6939. ; 19:10, s. 1195-1207
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Tidskriftsartikel (refereegranskat)abstract
- In this article a Switching Model Predictive Attitude Controller for an Unmanned quadrotor Helicopter subject to atmospheric disturbances is presented. The proposed control scheme is computed based on a Piecewise Affine (PWA) model of the quadrotor’s attitude dynamics, where the effects of the atmospheric turbulence are taken into consideration as additive disturbances. The switchings among the PWA models are ruled by the rate of the rotation angles and for each PWA system a corresponding model predictive controller is computed. The suggested algorithm is verified in experimental studies in the execution of sudden maneuvers subject to forcible wind disturbances. The quadrotor rejects the induced wind–disturbances while performing accurate attitude tracking.
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| 48. |
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| 49. |
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| 50. |
- Andrikopoulos, Georgios, et al.
(författare)
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A Survey on applications of pneumatic artificial muscles
- 2011
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Ingår i: 19th Mediterranean Conference on Control and Automation, MED 2011. - Piscataway, NJ : IEEE Communications Society. - 9781457701252 ; , s. 1439-1446
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Konferensbidrag (refereegranskat)abstract
- The aim of this article is to present a survey on applications of Pneumatic Artificial Muscles (PAMs). PAMs are highly non–linear pneumatic actuators where their elongation is proportional to the interval pressure. During the last decade, there has been a significant increase in the industrial and scientific utilization of PAMs due to their advantages such as high strength and small weight, while various types of PAMs with different technical characteristics have been appeared in the relative scientific literature. This article will summarize the key enabling applications in PAMs that are focusing in the following areas: a) Biorobotic, b) Medical, c) Industrial, and d) Aerospace applications
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