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Publications

Publications by CRAS

2018

A note on Nash equilibrium with wave dynamics and boundary control: controllability, observability and stabilizability considerations

Authors
Azevedo Perdicoulisr, TP; Jank, G; Lopes dos Santos, PL;

Publication
INTERNATIONAL JOURNAL OF CONTROL

Abstract
In this paper, the gas dynamics within the pipelines is written as a wave repetitive process, and modified in a way that the dynamics is driven by the boundary conditions. We study controllability of the system through boundary control and every agent, as well as observability of the system being steered by initial and boundary data. Next, we obtain sufficient criteria for the existence and uniqueness of boundary equilibrium controls. From the point of view of some applications, e.g. in high pressure gas pipeline management, it seems to make sense to consider boundary data controls. The same problem is then extended to its infinite counterpart since it may run infinitely and, in this case, we become interested in studying its stabilisation.

2018

Estimation and control of multidimensional systems

Authors
Azevedo Perdicoulis, TPCA;

Publication
INTERNATIONAL JOURNAL OF CONTROL

Abstract

2018

The secrets of segway revealed to students: Revisiting the inverted pendulum

Authors
Perdicoúlis, TPA; Dos Santos, PL;

Publication
13th APCA International Conference on Control and Soft Computing, CONTROLO 2018 - Proceedings

Abstract
This article revisits the inverted pendulum-in particular, analyses a simplified model of a Segway, with a view to exploring its capabilities in Control Systems Engineering education. The integration between the theoretic and practical side is achieved through simulation, and in particular by using MathWorks software. We also present a structure for the work to be done in the Laboratory class and propose a solution for the problem. © 2018 IEEE.

2017

Unmanned Maritime Systems for Search and Rescue

Authors
Matos, A; Silva, E; Almeida, J; Martins, A; Ferreira, H; Ferreira, B; Alves, J; Dias, A; Fioravanti, S; Bertin, D; Lobo, V;

Publication
Search and Rescue Robotics - From Theory to Practice

Abstract

2017

Cooperative Deep Water Seafloor Mapping with Heterogeneous Robotic Platforms

Authors
Cruz, N; Abreu, N; Almeida, J; Almeida, R; Alves, J; Dias, A; Ferreira, B; Ferreira, H; Gonçalves, C; Martins, A; Melo, J; Pinto, A; Pinto, V; Silva, A; Silva, H; Matos, A; Silva, E;

Publication
OCEANS 2017 - ANCHORAGE

Abstract
This paper describes the PISCES system, an integrated approach for fully autonomous mapping of large areas of the ocean in deep waters. A deep water AUV will use an acoustic navigation system to compute is position with bounded error. The range limitation will be overcome by a moving baseline scheme, with the acoustic sources installed in robotic surface vessels with previously combined trajectories. In order to save power, all systems will have synchronized clocks and implement the One Way Travel Time scheme. The mapping system will be a combination of an off-the-shelf MBES with a new long range bathymetry system, with a source on a moving surface vessel and the receivers on board the AUV. The system is being prepared to participate in round one of the XPRIZE challenge.

2017

A lightweight docking station for a hovering AUV

Authors
Cruz, NA; Matos, AC; Almeida, RM; Ferreira, BM;

Publication
2017 IEEE OES International Symposium on Underwater Technology, UT 2017

Abstract
The concept of underwater docking stations has long been proposed to support the long term deployment of AUVs, but the number of successful solutions is still very disappointing. Hovering type AUVs can navigate arbitrarily slow, simplifying the docking maneuver and the requirements for the receiving structure. This paper describes a docking system that was developed to extend the mission duration of the MARES AUV, a man portable hovering type AUV. Given the wide range of operational scenarios and configurations of this AUV, one of the design requirements was to have a simple modular structure, that could easily be reconfigured to support different vehicle configurations, deployment scenarios and docking maneuvers. The paper provides details of the mechanical aspects, the onboard electronic subsystems, and the general operational procedure, as well as preliminary data from the first trials. © 2017 IEEE.

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