Artur Pereira - Academia.edu (original) (raw)
Papers by Artur Pereira
This paper presents a novel method for people detection and tracking using depth images provided ... more This paper presents a novel method for people detection and tracking using depth images provided by Kinetic camera. The depth image captured by a Kinect camera is analysed using its histogram, allowing for the depth image to be divided in slices, making the retrieval of regions of interest a simple and computationally light process when compared to point clouds. These regions are then classified as human or not using a template matching technique. An efficient gradient descent algorithm is used to perform the template matching, using the RPROP algorithm, and the tracking is performed based on color image histogram comparison for each region of interest, in consecutive frames. The proposed method is viable for on-line detection and tracking of people and has been tested in a mobile platform in an unconstrained environment.
2005 Purtuguese Conference on Artificial Intelligence, 2005
This paper describes the work undertaken, in a twoweeks time, to put a robotic football player do... more This paper describes the work undertaken, in a twoweeks time, to put a robotic football player doing autonomous driving in a robotics contest. The robot was designed to play football in the RoboCup Middle Size League, and was used without modifications. During competition, it has to complete two laps of a circuit, autonomously, as fast as possible, and without incurring into infractions. The sensory system was mainly based upon two webcams, one allowing for omnidirectional vision and the other directed to the robot front.
IFAC Proceedings Volumes, 2006
In this paper we present a framework developed for the CAMBADA Middle-sized league robotic team, ... more In this paper we present a framework developed for the CAMBADA Middle-sized league robotic team, which allows human developers to better understand the robots actions during a game. Robotic soccer teams are in their nature dynamic multi-process and multi-agent systems, and knowing what is happening in all processes running on the agents at the same time is a hard task. To accomplish this task we developed a framework to create log files, one per process, and to interlace them later. The logs represent robot's knowledge. The framework allows the synchronization and visualization of logs and videos. Videos give the actual real behaviors. This will allow us to understand the robot's reasoning. A GUI utility to navigate and search inside log files was also developed.
enide.net
Resumo Este artigo apresenta uma visao geral do visualizador, construıdo para o ambiente de si... more Resumo Este artigo apresenta uma visao geral do visualizador, construıdo para o ambiente de si-mulaçao Ciber-Rato, desde a sua especificaçao até `a sua implementaçao prática. O ambiente Ciber-Rato consiste num conjunto de aplicaçoes que cons-troem um ...
www-lehre.informatik.uos.de
Abstract.. This paper introduces both the Eco–Be robotic platform and the RoboCup Mixed Reality C... more Abstract.. This paper introduces both the Eco–Be robotic platform and the RoboCup Mixed Reality Competition and the research under development on the FC Portugal team in the context of this league. The Eco-Bes and the Mixed reality competition present an immediate, simple application for developing complete teams for cooperative robotic applications. The Eco-Be is a very small mobile vehicle, also known as Citizen Micro robot, remotely controlled by infrared commands. This platform provides interesting possibilities like ...
University of Aveiro, …, 2008
This paper describes the CAMBADA middle-size robotic soccer team for the purpose of qualification... more This paper describes the CAMBADA middle-size robotic soccer team for the purpose of qualification to RoboCup'2008 . Last year improvements have been made mostly in the vision system, in the high-level coordination and control and in the information int egration and localization. Previous experience of some elements of the team in the RoboCup Simulation League has been highly relevant particularly
Lecture Notes in Computer Science, 2019
This paper proposes a framework designed to generate a closed-loop walking engine for a humanoid ... more This paper proposes a framework designed to generate a closed-loop walking engine for a humanoid robot. In particular, the core of this framework is an abstract dynamics model which is composed of two masses that represent the lower and the upper body of a humanoid robot. Moreover, according to the proposed dynamics model, the low-level controller is formulated as a Linear-Quadratic-Gaussian (LQG) controller that is able to robustly track the desired trajectories. Besides, this framework is fully parametric which allows using an optimization algorithm to find the optimum parameters. To examine the performance of the proposed framework, a set of simulation using a simulated Nao robot in the RoboCup 3D simulation environment has been carried out. Simulation results show that the proposed framework is capable of providing fast and reliable omnidirectional walking. After optimizing the parameters using genetic algorithm (GA), the maximum forward walking velocity that we have achieved was 80.5cm/s.
arXiv (Cornell University), Nov 27, 2020
This work aims to combine machine learning and control approaches for legged robots, and develope... more This work aims to combine machine learning and control approaches for legged robots, and developed a hybrid framework to achieve new capabilities of balancing against external perturbations. The framework embeds a kernel which is a fully parametric closed-loop gait generator based on analytical control. On top of that, a neural network with symmetric partial data augmentation learns to automatically adjust the parameters for the gait kernel and to generate compensatory actions for all joints as the residual dynamics, thus significantly augmenting the stability under unexpected perturbations. The performance of the proposed framework was evaluated across a set of challenging simulated scenarios. The results showed considerable improvements compared to the baseline in recovering from large external forces. Moreover, the produced behaviours are more natural, human-like and robust against noisy sensing.
Current packaging machine vendors do not provide any automated mechanism for blank feeding and th... more Current packaging machine vendors do not provide any automated mechanism for blank feeding and the state of the art is to have a human operator dedicated to feed the blank piles to the packaging machine. This is a tedious, repetitive and tiring task. This also results in problems with unintentional errors, such as using the wrong pile of blanks. An alternative solution is the use of a fixed robotic arm surrounded by a protective cage. However, this solution is restricted to a single packaging machine, a unique type of blank shapes and does not cooperate with humans. TIMAIRIS is a joint effort between IMA S.p.A., Italy, (IMA) and the Universidade de Aveiro, Portugal, (UAVR), promoted by the European Robotics Challenges (EuRoC) project. Together, we propose a system based on a mobile manipulator for flexible, autonomous and collaborative blank feeding of packaging machines on industrial shop floor. The system provides a software architecture that allows a mobile robot to take high lev...
2017 IEEE International Conference on Autonomous Robot Systems and Competitions (ICARSC), 2017
The adoption of robotics technology has the potential to advance quality, efficiency and safety f... more The adoption of robotics technology has the potential to advance quality, efficiency and safety for manufacturing enterprises, in particular small and medium-sized enterprises. This paper presents a human-robot interaction (HRI) system that enables a robot to receive commands, provide information to a human team mate and ask them a favor. In order to build robust HRI system based on gesture recognition, three key issues are addressed: richness, multiple feature fusion and failure verification. The developed system has been tested and validated in a realistic lab with a real mobile manipulator and a human team mate to solve a puzzle game.
ArXiv, 2020
Although humanoid robots are made to resemble humans, their stability is not yet comparable to ou... more Although humanoid robots are made to resemble humans, their stability is not yet comparable to ours. When facing external disturbances, humans efficiently and unconsciously combine a set of strategies to regain stability. This work deals with the problem of developing a robust hybrid stabilizer system for biped robots. The Linear Inverted Pendulum (LIP) and Divergent Component of Motion (DCM) concepts are used to formulate the biped locomotion and stabilization as an analytical control framework. On top of that, a neural network with symmetric partial data augmentation learns residuals to adjust the joint's position, and thus improving the robot's stability when facing external perturbations. The performance of the proposed framework was evaluated across a set of challenging simulation scenarios. The results show a considerable improvement over the baseline in recovering from large external forces. Moreover, the produced behaviors are human-like and robust to considerably no...
Robotics and Autonomous Systems, 2021
This paper proposes a modular framework to generate robust biped locomotion using a tight couplin... more This paper proposes a modular framework to generate robust biped locomotion using a tight coupling between an analytical walking approach and deep reinforcement learning. This framework is composed of six main modules which are hierarchically connected to reduce the overall complexity and increase its flexibility. The core of this framework is a specific dynamics model which abstracts a humanoid's dynamics model into two masses for modeling upper and lower body. This dynamics model is used to design an adaptive reference trajectories planner and an optimal controller which are fully parametric. Furthermore, a learning framework is developed based on Genetic Algorithm (GA) and Proximal Policy Optimization (PPO) to find the optimum parameters and to learn how to improve the stability of the robot by moving the arms and changing its center of mass (COM) height. A set of simulations are performed to validate the performance of the framework using the official RoboCup 3D League simulation environment. The results validate the performance of the framework, not only in creating a fast and stable gait but also in learning to improve the upper body efficiency.
This paper describes the CAMBADA Middle Size robotic soccer team for the purpose of qualification... more This paper describes the CAMBADA Middle Size robotic soccer team for the purpose of qualification to RoboCup'2013. During the last year, improvements have been made in a significant number of components of the robot. Most important changes include the ongoing implementation of a new platform, implementation of a new modular vision system and the use of new digital cameras, ball detection in 3D space, improvements in the world modeling and sensor fusion, development of a model for trajectory generation and several improvements in the high-level coordination and control, namely a new model for the software agent based on utilities, that includes the use of setplays, strategic positioning, passes and learning for behaviors development.
Abstract. This paper presents the newly created CAMBADA@ Home team for the purpose of qualificati... more Abstract. This paper presents the newly created CAMBADA@ Home team for the purpose of qualification to the RoboCup@ Home competition in RoboCup'2011. The CAMBADA@ Home team is built on the success of the CAMBADA robotic soccer team which competes in the Middle Size League.
Revista do DETUA, 2002
Sumário Este artigo descreve a modalidade Ciber-Rato do Concurso Micro-Rato da Universidade de Av... more Sumário Este artigo descreve a modalidade Ciber-Rato do Concurso Micro-Rato da Universidade de Aveiro. Nesta modalidade as provas decorrem num ambiente virtual criado por um simulador. O sistema de simulação é distribuído e baseado em tecnologias abertas. Os ...
Revista do DETUA, 2002
Resumo - O Ciber-Rato é uma modalidade do concurso Micro-Rato destinada a concorrentes que apenas... more Resumo - O Ciber-Rato é uma modalidade do concurso Micro-Rato destinada a concorrentes que apenas se queiram envolver nos aspectos algorítmicos do controlo de robots móveis e autónomos. Esta modalidade é suportada por um ambiente de simulação de robots e ...
Proceedings of the 2nd International Living Usability Lab Workshop on AAL Latest Solutions, Trends and Applications, 2012
Current societies in developed countries face a serious problem of aged population. The growing n... more Current societies in developed countries face a serious problem of aged population. The growing number of people with reduced health and capabilities, allied with the fact that elders are reluctant to leave their own homes to move to nursing homes, requires innovative solutions since continuous home care can be very expensive and dedicated 24/7 care can only be accomplished by more than one care-giver. This paper presents the proposal of a robotic platform for elderly care integrated in the Living Usability Lab for Next Generation Networks. The project aims at developing technologies and services tailored to enable the active aging and independent living of the elderly population. The proposed robotic platform is based on the CAMBADA robotic soccer platform, with the necessary modifications, both at hardware and software levels, while simultaneously applying the experiences achieved in the robotic soccer environment.
Generating robust locomotion for a humanoid robot in the presence of disturbances is difficult be... more Generating robust locomotion for a humanoid robot in the presence of disturbances is difficult because of its high number of degrees of freedom and its unstable nature. In this paper, we used the concept of Divergent Component of Motion (DCM) and propose an optimal closed-loop controller based on Linear-Quadratic-Gaussian to generate a robust and stable walking for humanoid robots. The biped robot dynamics has been approximated using the Linear Inverted Pendulum Model (LIPM). Moreover, we propose a controller to adjust the landing location of the swing leg to increase the withstanding level of the robot against a severe external push. The performance and also the robustness of the proposed controller is analyzed and verified by performing a set of simulations using MATLAB. The simulation results showed that the proposed controller is capable of providing a robust walking even in the presence of disturbances and in challenging situations.
This paper presents a novel method for people detection and tracking using depth images provided ... more This paper presents a novel method for people detection and tracking using depth images provided by Kinetic camera. The depth image captured by a Kinect camera is analysed using its histogram, allowing for the depth image to be divided in slices, making the retrieval of regions of interest a simple and computationally light process when compared to point clouds. These regions are then classified as human or not using a template matching technique. An efficient gradient descent algorithm is used to perform the template matching, using the RPROP algorithm, and the tracking is performed based on color image histogram comparison for each region of interest, in consecutive frames. The proposed method is viable for on-line detection and tracking of people and has been tested in a mobile platform in an unconstrained environment.
2005 Purtuguese Conference on Artificial Intelligence, 2005
This paper describes the work undertaken, in a twoweeks time, to put a robotic football player do... more This paper describes the work undertaken, in a twoweeks time, to put a robotic football player doing autonomous driving in a robotics contest. The robot was designed to play football in the RoboCup Middle Size League, and was used without modifications. During competition, it has to complete two laps of a circuit, autonomously, as fast as possible, and without incurring into infractions. The sensory system was mainly based upon two webcams, one allowing for omnidirectional vision and the other directed to the robot front.
IFAC Proceedings Volumes, 2006
In this paper we present a framework developed for the CAMBADA Middle-sized league robotic team, ... more In this paper we present a framework developed for the CAMBADA Middle-sized league robotic team, which allows human developers to better understand the robots actions during a game. Robotic soccer teams are in their nature dynamic multi-process and multi-agent systems, and knowing what is happening in all processes running on the agents at the same time is a hard task. To accomplish this task we developed a framework to create log files, one per process, and to interlace them later. The logs represent robot's knowledge. The framework allows the synchronization and visualization of logs and videos. Videos give the actual real behaviors. This will allow us to understand the robot's reasoning. A GUI utility to navigate and search inside log files was also developed.
enide.net
Resumo Este artigo apresenta uma visao geral do visualizador, construıdo para o ambiente de si... more Resumo Este artigo apresenta uma visao geral do visualizador, construıdo para o ambiente de si-mulaçao Ciber-Rato, desde a sua especificaçao até `a sua implementaçao prática. O ambiente Ciber-Rato consiste num conjunto de aplicaçoes que cons-troem um ...
www-lehre.informatik.uos.de
Abstract.. This paper introduces both the Eco–Be robotic platform and the RoboCup Mixed Reality C... more Abstract.. This paper introduces both the Eco–Be robotic platform and the RoboCup Mixed Reality Competition and the research under development on the FC Portugal team in the context of this league. The Eco-Bes and the Mixed reality competition present an immediate, simple application for developing complete teams for cooperative robotic applications. The Eco-Be is a very small mobile vehicle, also known as Citizen Micro robot, remotely controlled by infrared commands. This platform provides interesting possibilities like ...
University of Aveiro, …, 2008
This paper describes the CAMBADA middle-size robotic soccer team for the purpose of qualification... more This paper describes the CAMBADA middle-size robotic soccer team for the purpose of qualification to RoboCup'2008 . Last year improvements have been made mostly in the vision system, in the high-level coordination and control and in the information int egration and localization. Previous experience of some elements of the team in the RoboCup Simulation League has been highly relevant particularly
Lecture Notes in Computer Science, 2019
This paper proposes a framework designed to generate a closed-loop walking engine for a humanoid ... more This paper proposes a framework designed to generate a closed-loop walking engine for a humanoid robot. In particular, the core of this framework is an abstract dynamics model which is composed of two masses that represent the lower and the upper body of a humanoid robot. Moreover, according to the proposed dynamics model, the low-level controller is formulated as a Linear-Quadratic-Gaussian (LQG) controller that is able to robustly track the desired trajectories. Besides, this framework is fully parametric which allows using an optimization algorithm to find the optimum parameters. To examine the performance of the proposed framework, a set of simulation using a simulated Nao robot in the RoboCup 3D simulation environment has been carried out. Simulation results show that the proposed framework is capable of providing fast and reliable omnidirectional walking. After optimizing the parameters using genetic algorithm (GA), the maximum forward walking velocity that we have achieved was 80.5cm/s.
arXiv (Cornell University), Nov 27, 2020
This work aims to combine machine learning and control approaches for legged robots, and develope... more This work aims to combine machine learning and control approaches for legged robots, and developed a hybrid framework to achieve new capabilities of balancing against external perturbations. The framework embeds a kernel which is a fully parametric closed-loop gait generator based on analytical control. On top of that, a neural network with symmetric partial data augmentation learns to automatically adjust the parameters for the gait kernel and to generate compensatory actions for all joints as the residual dynamics, thus significantly augmenting the stability under unexpected perturbations. The performance of the proposed framework was evaluated across a set of challenging simulated scenarios. The results showed considerable improvements compared to the baseline in recovering from large external forces. Moreover, the produced behaviours are more natural, human-like and robust against noisy sensing.
Current packaging machine vendors do not provide any automated mechanism for blank feeding and th... more Current packaging machine vendors do not provide any automated mechanism for blank feeding and the state of the art is to have a human operator dedicated to feed the blank piles to the packaging machine. This is a tedious, repetitive and tiring task. This also results in problems with unintentional errors, such as using the wrong pile of blanks. An alternative solution is the use of a fixed robotic arm surrounded by a protective cage. However, this solution is restricted to a single packaging machine, a unique type of blank shapes and does not cooperate with humans. TIMAIRIS is a joint effort between IMA S.p.A., Italy, (IMA) and the Universidade de Aveiro, Portugal, (UAVR), promoted by the European Robotics Challenges (EuRoC) project. Together, we propose a system based on a mobile manipulator for flexible, autonomous and collaborative blank feeding of packaging machines on industrial shop floor. The system provides a software architecture that allows a mobile robot to take high lev...
2017 IEEE International Conference on Autonomous Robot Systems and Competitions (ICARSC), 2017
The adoption of robotics technology has the potential to advance quality, efficiency and safety f... more The adoption of robotics technology has the potential to advance quality, efficiency and safety for manufacturing enterprises, in particular small and medium-sized enterprises. This paper presents a human-robot interaction (HRI) system that enables a robot to receive commands, provide information to a human team mate and ask them a favor. In order to build robust HRI system based on gesture recognition, three key issues are addressed: richness, multiple feature fusion and failure verification. The developed system has been tested and validated in a realistic lab with a real mobile manipulator and a human team mate to solve a puzzle game.
ArXiv, 2020
Although humanoid robots are made to resemble humans, their stability is not yet comparable to ou... more Although humanoid robots are made to resemble humans, their stability is not yet comparable to ours. When facing external disturbances, humans efficiently and unconsciously combine a set of strategies to regain stability. This work deals with the problem of developing a robust hybrid stabilizer system for biped robots. The Linear Inverted Pendulum (LIP) and Divergent Component of Motion (DCM) concepts are used to formulate the biped locomotion and stabilization as an analytical control framework. On top of that, a neural network with symmetric partial data augmentation learns residuals to adjust the joint's position, and thus improving the robot's stability when facing external perturbations. The performance of the proposed framework was evaluated across a set of challenging simulation scenarios. The results show a considerable improvement over the baseline in recovering from large external forces. Moreover, the produced behaviors are human-like and robust to considerably no...
Robotics and Autonomous Systems, 2021
This paper proposes a modular framework to generate robust biped locomotion using a tight couplin... more This paper proposes a modular framework to generate robust biped locomotion using a tight coupling between an analytical walking approach and deep reinforcement learning. This framework is composed of six main modules which are hierarchically connected to reduce the overall complexity and increase its flexibility. The core of this framework is a specific dynamics model which abstracts a humanoid's dynamics model into two masses for modeling upper and lower body. This dynamics model is used to design an adaptive reference trajectories planner and an optimal controller which are fully parametric. Furthermore, a learning framework is developed based on Genetic Algorithm (GA) and Proximal Policy Optimization (PPO) to find the optimum parameters and to learn how to improve the stability of the robot by moving the arms and changing its center of mass (COM) height. A set of simulations are performed to validate the performance of the framework using the official RoboCup 3D League simulation environment. The results validate the performance of the framework, not only in creating a fast and stable gait but also in learning to improve the upper body efficiency.
This paper describes the CAMBADA Middle Size robotic soccer team for the purpose of qualification... more This paper describes the CAMBADA Middle Size robotic soccer team for the purpose of qualification to RoboCup'2013. During the last year, improvements have been made in a significant number of components of the robot. Most important changes include the ongoing implementation of a new platform, implementation of a new modular vision system and the use of new digital cameras, ball detection in 3D space, improvements in the world modeling and sensor fusion, development of a model for trajectory generation and several improvements in the high-level coordination and control, namely a new model for the software agent based on utilities, that includes the use of setplays, strategic positioning, passes and learning for behaviors development.
Abstract. This paper presents the newly created CAMBADA@ Home team for the purpose of qualificati... more Abstract. This paper presents the newly created CAMBADA@ Home team for the purpose of qualification to the RoboCup@ Home competition in RoboCup'2011. The CAMBADA@ Home team is built on the success of the CAMBADA robotic soccer team which competes in the Middle Size League.
Revista do DETUA, 2002
Sumário Este artigo descreve a modalidade Ciber-Rato do Concurso Micro-Rato da Universidade de Av... more Sumário Este artigo descreve a modalidade Ciber-Rato do Concurso Micro-Rato da Universidade de Aveiro. Nesta modalidade as provas decorrem num ambiente virtual criado por um simulador. O sistema de simulação é distribuído e baseado em tecnologias abertas. Os ...
Revista do DETUA, 2002
Resumo - O Ciber-Rato é uma modalidade do concurso Micro-Rato destinada a concorrentes que apenas... more Resumo - O Ciber-Rato é uma modalidade do concurso Micro-Rato destinada a concorrentes que apenas se queiram envolver nos aspectos algorítmicos do controlo de robots móveis e autónomos. Esta modalidade é suportada por um ambiente de simulação de robots e ...
Proceedings of the 2nd International Living Usability Lab Workshop on AAL Latest Solutions, Trends and Applications, 2012
Current societies in developed countries face a serious problem of aged population. The growing n... more Current societies in developed countries face a serious problem of aged population. The growing number of people with reduced health and capabilities, allied with the fact that elders are reluctant to leave their own homes to move to nursing homes, requires innovative solutions since continuous home care can be very expensive and dedicated 24/7 care can only be accomplished by more than one care-giver. This paper presents the proposal of a robotic platform for elderly care integrated in the Living Usability Lab for Next Generation Networks. The project aims at developing technologies and services tailored to enable the active aging and independent living of the elderly population. The proposed robotic platform is based on the CAMBADA robotic soccer platform, with the necessary modifications, both at hardware and software levels, while simultaneously applying the experiences achieved in the robotic soccer environment.
Generating robust locomotion for a humanoid robot in the presence of disturbances is difficult be... more Generating robust locomotion for a humanoid robot in the presence of disturbances is difficult because of its high number of degrees of freedom and its unstable nature. In this paper, we used the concept of Divergent Component of Motion (DCM) and propose an optimal closed-loop controller based on Linear-Quadratic-Gaussian to generate a robust and stable walking for humanoid robots. The biped robot dynamics has been approximated using the Linear Inverted Pendulum Model (LIPM). Moreover, we propose a controller to adjust the landing location of the swing leg to increase the withstanding level of the robot against a severe external push. The performance and also the robustness of the proposed controller is analyzed and verified by performing a set of simulations using MATLAB. The simulation results showed that the proposed controller is capable of providing a robust walking even in the presence of disturbances and in challenging situations.