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Publications

Publications by António Paulo Moreira

1997

Intelligent and low cost continuous relative density measurement in batch fermenters

Authors
Moreira, APGM; de Carvalho, JLM;

Publication
INTELLIGENT COMPONENTS AND INSTRUMENTS FOR CONTROL APPLICATIONS 1997 (SICICA'97)

Abstract
In this article we present two methods for the real time automatic measurement of the relative density. The first one relies on the heat generated during the fermentation which requires no additional sensors in the tanks. It is based on the thermal model of the tank and the only additional requirements are the measurement of the temperature of the surrounding air. The other method is based on two low-cost pressure sensors with an algorithm for autocalibration and compensation of temperature perturbation. The autocalibration is done during fermenter feeding and with only one manual measurement of the relative density.

2009

A nonlinear mobile robot modeling applied to a model predictive controller

Authors
Conceição, AS; Moreira, AP; Costa, PJ;

Publication
Proceedings of the 2009 ACM Symposium on Applied Computing (SAC), Honolulu, Hawaii, USA, March 9-12, 2009

Abstract

2008

Humanoid Robot Simulation with a Joint Trajectory Optimized Controller

Authors
Lima, JL; Goncalves, JC; Costa, PG; Moreira, AP;

Publication
2008 IEEE INTERNATIONAL CONFERENCE ON EMERGING TECHNOLOGIES AND FACTORY AUTOMATION, PROCEEDINGS

Abstract
This paper describes a joint trajectory optimized controller for a humanoid robot simulator following the real robot characteristics. As simulation is a powerful tool for speeding up the control software development, the proposed accurate simulator allows to fulfill this goal. The simulator, based on the Open Dynamics Engine and GLScene graphics library, provides instant visual feedback. The proposed simulator, with realistic dynamics, allows to design and test behaviours and control strategies without access to the real hardware in order to carry out research on robot control without damaging the real robot in the early stages of the development. The joints controller techniques, such as acceleration, speed and energy consumption minimization are discussed and experimental results are presented in order to validate the proposed simulator.

2009

HUMANOID REALISTIC SIMULATOR The Servomotor Joint Modeling

Authors
Lima, JL; Goncalves, JA; Costa, PG; Moreira, AP;

Publication
ICINCO 2009: PROCEEDINGS OF THE 6TH INTERNATIONAL CONFERENCE ON INFORMATICS IN CONTROL, AUTOMATION AND ROBOTICS, VOL 2: ROBOTICS AND AUTOMATION

Abstract
This paper presents a humanoid servomotor model that can be used in simulations. Once simulation is a tool that reduces the software production time, it was developed a realistic simulator that own the humanoid features. Based on a real platform, the simulator is validated when compared with the reality.

2010

HUMANOID LOW-LEVEL CONTROLLER DEVELOPMENT BASED ON A REALISTIC SIMULATION

Authors
Lima, JL; Goncalves, JC; Costa, PG; Moreira, AP;

Publication
INTERNATIONAL JOURNAL OF HUMANOID ROBOTICS

Abstract
This article describes a joint trajectory optimized controller developed in a humanoid robot simulator following the real robot characteristics. As simulation is a powerful tool for speeding up the control software development, the proposed accurate simulator allows to fulfill this goal. The simulator, based on the Open Dynamics Engine and GLScene graphics library, provides instant visual feedback. The proposed simulator, with realistic dynamics, allows to design and test behaviors and control strategies without access to the real hardware in order to carry out research on robot control without damaging the real robot. The low-level joints controller techniques, such as acceleration, speed, and energy consumption minimization, are discussed and experimental results are presented in order to validate the proposed simulator.

2012

Indoor localization system based on artificial landmarks and monocular vision

Authors
Pinto, AMG; Moreira, AP; Costa, PG;

Publication
Telkomnika

Abstract
This paper presents a visual localization approach that is suitable for domestic and industrial environments as it enables accurate, reliable and robust pose estimation. The mobile robot is equipped with a single camera which update sits pose whenever a landmark is available on the field of view. The innovation presented by this research focuses on the artificial landmark system which has the ability to detect the presence of the robot, since both entities communicate with each other using an infrared signal protocol modulated in frequency. Besides this communication capability, each landmark has several high intensity light-emitting diodes (LEDs) that shine only for some instances according to the communication, which makes it possible for the camera shutter and the blinking of the LEDs to synchronize. This synchronization increases the system tolerance concerning changes in brightness in the ambient lights over time, independently of the landmarks location. Therefore, the environment's ceiling is populated with several landmarks and an Extended Kalman Filter is used to combine the dead-reckoning and landmark information. This increases the flexibility of the system by reducing the number of landmarks required. The experimental evaluation was conducted in a real indoor environment with an autonomous wheelchair prototype.

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