Jorge Dias

Jorge Dias

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Jorge Dias

Khalifa University, Abu Dhabi, UAE

Research Focus & Metrics

Academic Career Length

41Years (1986-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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19 October 2018 in IEEE Transactions on Robotics
Verified
Journal Article
Closed access
FRFederico Renda
Federico Renda
FBFrederic Boyer
Frederic Boyer
JDJorge Dias
Jorge Dias
LSLakmal Seneviratne
Lakmal Seneviratne
Nowadays, the most adopted model for the design and control of soft robots is the piecewise constant curvature model, with its consolidated benefits and drawbacks. In this work, an alternative model for multisection soft manipulator dynamics is presented based on a discrete Cosserat approach, in which the continuous Cosserat model is discretized by assuming a piecewise constant strain along the soft arm. As a consequence, the soft manipulator state is described by a finite set of constant strains. This approach has several advantages with respect to the existing models. First, it takes into account shear and torsional deformations, which are both essential to cope with out-of-plane external loads. Furthermore, it inherits desirable geometrical and mechanical properties of the continuous Cosserat model, such as intrinsic parameterization and greater generality. Finally, this approach allows to extend to soft manipulators, the recursive composite-rigid-body and articulated-body algorithms, whose performances are compared through a cantilever beam simulation. The soundness of the model is demonstrated through extensive simulation and experimental results.

22 April 2014 in Unmanned Systems
Verified
Journal Article
Closed access
GCGuowei Cai
Guowei Cai
JDJorge Dias
Jorge Dias
LSLakmal Seneviratne
Lakmal Seneviratne

1 June 2007 in The International Journal of Robotics Research
Verified
Journal Article
Closed access
PDF file
PCPeter Corke
Peter Corke
JLJorge Lobo
Jorge Lobo
JDJorge Dias
Jorge Dias
In this paper we present a tutorial introduction to two important senses for biological and robotic systems — inertial and visual perception. We discuss the fundamentals of these two sensing modalities from a biological and an engineering perspective. Digital camera chips and micro-machined accelerometers and gyroscopes are now commodities, and when combined with today's available computing can provide robust estimates of self-motion as well 3D scene structure, without external infrastructure. We discuss the complementarity of these sensors, describe some fundamental approaches to fusing their outputs and survey the field.

20 May 2021 in Sensors
Verified
Journal Article
Open access
PDF file
Sandro MagalhãesSandro Magalhães
Sandro Magalhães
LCLuís Castro
Luís Castro
Germano MoreiraGermano Moreira
Germano Moreira
Filipe Neves dos SantosFilipe Neves dos Santos
Filipe Neves dos Santos
Mario CunhaMario Cunha
Mario Cunha
Antonio Paulo MoreiraAntonio Paulo Moreira
Antonio Paulo Moreira
The development of robotic solutions for agriculture requires advanced perception capabilities that can work reliably in any crop stage. For example, to automatise the tomato harvesting process in greenhouses, the visual perception system needs to detect the tomato in any life cycle stage (flower to the ripe tomato). The state-of-the-art for visual tomato detection focuses mainly on ripe tomato, which has a distinctive colour from the background. This paper contributes with an annotated visual dataset of green and reddish tomatoes. This kind of dataset is uncommon and not available for research purposes. This will enable further developments in edge artificial intelligence for in situ and in real-time visual tomato detection required for the development of harvesting robots. Considering this dataset, five deep learning models were selected, trained and benchmarked to detect green and reddish tomatoes grown in greenhouses. Considering our robotic platform specifications, only the Single-Shot MultiBox Detector (SSD) and YOLO architectures were considered. The results proved that the system can detect green and reddish tomatoes, even those occluded by leaves. SSD MobileNet v2 had the best performance when compared against SSD Inception v2, SSD ResNet 50, SSD ResNet 101 and YOLOv4 Tiny, reaching an F1-score of 66.15%, an mAP of 51.46% and an inference time of 16.44ms with the NVIDIA Turing Architecture platform, an NVIDIA Tesla T4, with 12 GB. YOLOv4 Tiny also had impressive results, mainly concerning inferring times of about 5 ms.

1 June 2007 in The International Journal of Robotics Research
Verified
Journal Article
Closed access
PDF file
JLJorge Lobo
Jorge Lobo
JDJorge Dias
Jorge Dias
This paper proposes an approach to calibrate off-the-shelf cameras and inertial sensors to have a useful integrated system to be used in static and dynamic situations. When both sensors are integrated in a system their relative pose needs to be determined. The rotation between the camera and the inertial sensor can be estimated, concurrently with camera calibration, by having both sensors observe the vertical direction in several poses. The camera relies on a vertical chequered planar target and the inertial sensor on gravity to obtain a vertical reference. Depending on the setup and system motion, the translation between the two sensors can also be important. Using a simple passive turntable and static images, the translation can be estimated. The system needs to be placed in several poses and adjusted to turn about the inertial sensor centre, so that the lever arm to the camera can be determined. Simulation and real data results are presented to show the validity and simple requirements of the proposed methods.

1 June 2015
Verified
Conference Paper
Closed access
ASAdnan S. Saeed
Adnan S. Saeed
Ahmad Bani YounesAhmad Bani Younes
Ahmad Bani Younes
SIShafiqul Islam
Shafiqul Islam
JDJorge Dias
Jorge Dias
LSLakmal Seneviratne
Lakmal Seneviratne
GCGuowei Cai
Guowei Cai
This article presents a review on the platform design, dynamic modeling and control of hybrid Unmanned Aerial Vehicles (UAVs). For now, miniature UAVs which have experienced a tremendous development are dominated by two main types, i.e., fixed-wing UAV and Vertical Take-Off and Landing (VTOL) UAV, each of which, however, has its own inherent limitations on such as flexibility, payload, axnd endurance. Enhanced popularity and interest are recently gained by a newer type of UAVs, named hybrid UAV that integrates the beneficial features of both conventional ones. In this paper, a technical overview of the recent advances of the hybrid UAV is presented. More specifically, the hybrid UAV's platform design together with the associated technical details and features are introduced first. Next, the work on hybrid UAV's flight dynamics modeling is then categorized and explained. As for the flight control system design for the hybrid UAV, several flight control strategies implemented are discussed and compared in terms of theory, linearity and implementation.