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Publications

Publications by CRIIS

2017

Dynamic analysis and comfort evaluation of a full suspension bicycle equipped with a MR damper

Authors
Pascoal, A; Gonçalves, J; Braz César, M;

Publication
COMPDYN 2017 - Proceedings of the 6th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering

Abstract
Typical vehicle suspension systems are based on passive energy dissipation devices. This type of systems have proven to be a reliable and economic approach, however they are not capable to modify its behavior in accordance with the road conditions. On the other hand, active systems allow a continuous control of the suspension response although requiring sensors, actuators and controllers which represents a more complex and expensive system, usually demanding high power requirements. A middle-term vibration control approach is to use the so-called semi-active systems with the adaptability of active systems and lower energy consumption. This paper aims to evaluate the comfort ridding of a full suspension bicycle equipped with semi-active open loop controlled suspension system using a magneto-rheological (MR) damper. The assessment was carried out based on the analysis of real data, extracted from the instrumented bicycle prototype. The experimental tests were made in a smooth indoor pavement and a cobblestone road. Finally, the results obtained with the proposed semi-active suspension control system are presented and discussed.

2017

Comparison of mesh generation algorithms for railroad reconstruction

Authors
Masson, JEN; Petry, MR;

Publication
2017 IEEE International Conference on Autonomous Robot Systems and Competitions, ICARSC 2017

Abstract
Inspection of railroad tracks is still predominantly performed visually by human inspectors. Due to the extension of the tracks this is a slow and tedious operation, significantly subjected to human errors and inconsistency. In this context, computer vision systems, composed of field-acquired images and processing algorithms, have a great potential to improve efficiency and to offer systematic inspection methodologies. In this paper the use of available point cloud and mesh generation algorithms to construct 3D surface of railroad tracks is investigated. To achieve this goal, images of a small track were acquired from several points-of-view. Next a comparison between several open and closed-source algorithms was performed, evaluating the number of 3D points, time consumption, RAM memory, GPU memory, number of faces, and the generated mesh. The results obtained demonstrate that with the right setup, current image processing methodologies can be used to construct 3D surfaces of uncontrolled scenarios, such as those of a real railroad environment. Regarding the comparison, SURE and Poisson presented the most accurate meshes. When comparing quantitative measures, though, Poisson presented a slightly better performance in time consumption, but SURE had a better RAM memory usage and a greater level of details. © 2017 IEEE.

2017

Beam for the steel fabrication industry robotic systems

Authors
Rocha, LF; Tavares, P; Malaca, P; Costa, C; Silva, J; Veiga, G;

Publication
ISARC 2017 - Proceedings of the 34th International Symposium on Automation and Robotics in Construction

Abstract
In this paper, we present a comparison between the older DSTV file format and the newer version of the IFC standard, dedicating special attention of its impact in the robotization of welding and cutting processes in the steel structure fabrication industry. In the last decade, we have seen in this industry a significant increase in the request for automation. These new requirements are imposed by a market focused on the productivity enhancement through automation. Because of this paradigm change, the information structure and workflow provided by the DSTV format needed to be revised, namely the one related with the plan and management of steel fabrication processes. Therefore, with this work we enhance the importance of the increased digitalization of information that the newer version of the IFC standard provide, by showing how this information can be used to develop advanced robotic cells. More in detail, we will focus on the automatic generation of robot welding and cutting trajectories, and in the automatic part assembly planning during components fabrications. Besides these advantages, as this information is normally described having as base a perfect CAD model of the metallic structure, the resultant robot trajectories will have some dimensional error when fitted with the real physical component. Hence, we also present some automatic approaches based on a laser scanner and simple heuristics to overcome this limitations.

2017

Fiabilidade e robustez da localização de robôs móveis

Authors
Héber Miguel Plácido Sobreira;

Publication

Abstract

2017

Mining the Usage Patterns of ROS Primitives

Authors
Santos, A; Cunha, A; Macedo, N; Arrais, R; dos Santos, FN;

Publication
2017 IEEE/RSJ INTERNATIONAL CONFERENCE ON INTELLIGENT ROBOTS AND SYSTEMS (IROS)

Abstract
The Robot Operating System (ROS) is nowadays one of the most popular frameworks for developing robotic applications. To ensure the (much needed) dependability and safety of such applications we forecast an increasing demand for ROS-specific coding standards, static analyzers, and tools alike. Unfortunately, the development of such standards and tools can be hampered by ROS modularity and configurability, namely the substantial number of primitives (and respective variants) that must, in principle, be considered. To quantify the severity of this problem, we have mined a large number of existing ROS packages to understand how its primitives are used in practice, and to determine which combinations of primitives are most popular. This paper presents and discusses the results of this study, and hopefully provides some guidance for future standardization efforts and tool developers.

2017

The European Project Semester at ISEP (EPS@ISEP) programme: Implementation results and ideas for improvement

Authors
Silva, MF; Malheiro, B; Guedes, PB; Ferreira, PD; Duarte, A;

Publication
Proceedings of the 45th SEFI Annual Conference 2017 - Education Excellence for Sustainability, SEFI 2017

Abstract
EPS is a one semester student-centred capstone programme designed by Arvid Andersen in Denmark, being currently offered by several European engineering schools. Its goal is to promote the development of scientific, technical and soft skills in students through multicultural teamwork and open, multidisciplinary project based learning. EPS, while an active learning framework, is focussed on problem-solving, communication, creativity, leadership, entrepreneurship, ethical reasoning and global contextual analysis. The School of Engineering of the Porto Polytechnic is an EPS provider since 2011, offering a 30 ECTU package with two-thirds assigned to the project module and one-third to project supportive complementary modules. A total of 138 students from 18 countries participated in the EPS@ISEP, while developing 28 multidisciplinary projects. Based on this experience, this paper identifies strengths, weaknesses and proposes ideas for the improvement of the programme.

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