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Publications

Publications by CRIIS

2020

Driverless Wheelchair for Patient's On-Demand Transportation in Hospital Environment

Authors
Baltazar, A; Petry, MR; Silva, MF; Moreira, AP;

Publication
2020 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC 2020)

Abstract
The transport of patients from the inpatient service to the operating room is a recurrent task in the hospital routine. This task is repetitive, non-ergonomic, time consuming, and requires the labor of patient transporters. In this paper is presented the design of a driverless wheelchair under development capable of providing an on-demand mobility service to hospitals. The proposed wheelchair can receive transportation requests directly from the hospital information management system, pick-up patients at their beds, navigate autonomously through different floors, avoid obstacles, communicate with elevators, and drop patients off at the designated destination.

2020

Evolution of Odometry Calibration Methods for Ground Mobile Robots

Authors
Sousa, RB; Petry, MR; Moreira, AP;

Publication
2020 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC 2020)

Abstract
Localisation is a critical problem in ground mobile robots. For dead reckoning, odometry is usually used. A disadvantage of using it alone is unbounded error accumulation. So, odometry calibration is critical in reducing error propagation. This paper presents an analysis of the developments and advances of systematic methods for odometry calibration. Four steering geometries were analysed, namely differential drive, Ackerman, tricycle and omnidirectional. It highlights the advances made on this field and covers the methods since UMBmark was proposed. The points of analysis are the techniques and test paths used, errors considered in calibration, and experiments made to validate each method. It was obtained fifteen methods for differential drive, three for Ackerman, two for tricycle, and three for the omnidirectional steering geometry. A disparity was noted, compared with the real utilisation, between the number of published works addressing differential drive and tricycle/Ackerman. Still, odometry continues evolving since UMBmark was proposed.

2020

Recursive Approach of Sub-Optimal Excitation Signal Generation and Optimal Parameter Estimation

Authors
Souza, MBA; Honorio, LD; de Oliveira, EJ; Moreira, APGM;

Publication
INTERNATIONAL JOURNAL OF CONTROL AUTOMATION AND SYSTEMS

Abstract
Optimal Input Design (OID) methodologies are developed to find a signal that could best estimate a set of parameters of a given model. Their application in constrained nonlinear systems, especially when the search space limits or the initial conditions are unknown, may present several difficulties due to the numerical instability related to the optimization processes. A good choice over the parameters possible ranges is a trade-off among numerical stability, search space size, and effectiveness, and it is hardly found. To deal with this problem, this paper proposes a series of changes in the Sub-Optimal Excitation Signal Generation and Optimal Parameter Estimation (SOESGOPE) methodology. First, the limits over the parameters are tightly adjusted according to their confidence. A recursive approach runs the optimization methodology, analyzes the solution's feasibility and marginal costs given by the Lagrange Multipliers, and selects a direction that could improve the system's response. This approach improves the convergence and the assertiveness of the estimation process. To validate this approach, some cases, including a parameters estimation of a mobile robot nonlinear system, are tested.

2020

Proof-of-concept study on a wave energy converter based on the roll oscillations of multipurpose offshore floating platforms

Authors
Clemente, D; Rosa Santos, P; Taveira Pinto, F; Martins, P; Paulo Moreira, A;

Publication
ENERGY CONVERSION AND MANAGEMENT

Abstract
Inspired by observing the motions of vessels at sea, the E-Motions has been proposed as an innovative concept capable of converting wave (and wind) induced roll oscillations on multipurpose offshore floating platforms into electricity. The device can be integrated, theoretically, into any type of offshore floating structure, given its simple 3-component design: floating platform, encasing and sliding Power Take-Off. This latter component can be sheltered from the marine environment by being placed within a casing, at deck level, or the hull of the offshore structure. With so much potential for application at sea, it was important to subject the E-Motions to an initial proof-of-concept, as done for other wave energy converters. This paper presents and discusses the main results and conclusions of an experimental study, carried out with a 1:40 reduced scale physical model, aimed at demonstrating the technical and technological viability of the E-Motions. It was found that, for the considered study variables, the device can operate without major incident and convert electricity from wave induced roll oscillations. Four ballast configurations were considered, of which two yielded higher power outputs. The average measured power reached as high as 11 kW and 13 kW, respectively, with the values reducing for wave period further away from the resonance range and lower wave heights. Power Take-Off damping was found to be an important variable that can considerably influence the energy generation process, yet it will be imperative to further assess this variable in combination with other pertinent variables, such as an external attached mass and different generators. This is key to better understand and describe the complex and non-linear relationship between the motions of the Power Take-Off and the floating platform components.

2020

Path Planning for ground robots in agriculture: a short review

Authors
Santos, LC; Santos, FN; Solteiro Pires, EJS; Valente, A; Costa, P; Magalhaes, S;

Publication
2020 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC 2020)

Abstract
The world's population is estimated to reach nine billion people by the year 2050, which indicates that agricultural productivity must increase sustainably. The mechanisation and automatisation of agricultural tasks is an essential step to face population growth. Ground robots have been developed along the last decade for several agricultural applications, being, the autonomous and safe navigation one of the hardest challenge in this development. Moving autonomously, a mobile platform involves different tasks, such as localisation, mapping, motion control, and path planning, a crucial step for autonomous operations. This article performs a survey of different applications for path planning techniques applied to various agricultural contexts. This paper analyses different agricultural applications and details about the employed path planning method. The conclusion indicates that path planning has been successfully applied to agrarian robots for field coverage and point-to-point navigation, being that coverage path planning is slightly more advanced in this field.

2020

Exchanging Challenge Based Learning Experiences in the Context of RoboSTEAM Erasmus+ Project

Authors
Conde, MÁ; Rodríguez Sedano, FJ; Fernández Llamas, C; Jesus, M; Ramos, MJ; Celis Tena, S; Gonçalves, J; Jormanainen, I; García Peñalvo, FJ;

Publication
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)

Abstract
In the context of the digital society, educational systems should prepare the students to succeed in a really volatile environment. In order to do so they require to acquire some specific competences that use to be related to STEAM Education. However, integrating STEAM is hard and requires of new methodologies and tools. RoboSTEAM is an Erasmus+ project that aims to facilitate this by using Challenge Based Learning and applying Physical Devices and Robotics. In order to know if what RoboSTEAM proposes work properly it must be tested in different contexts with different educational systems. The results of these tests should be compared, which requires of a common knowledge background. In order to achieve it RoboSTEAM proposes students and teachers exchanges between similar and different sociocultural environments, so they can learn how other people work in the project challenges and if what they do can be addressed by them in a similar way. The present work describes these exchanges, how they were planned and carried out and the main results obtained. From the exchanges carried out until now it is possible to say that they facilitate sharing knowledge that later can lead to better results in the project challenges and that they are enriching experiences both for students and for teachers. © 2020, Springer Nature Switzerland AG.

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