João Sequeira

Decentralized Sensor Fusion for Ubiquitous Networking Robotics in Urban Areas

In this article we explain the architecture for the environment and sensors that has been built for the European project URUS (Ubiquitous Networking Robotics in Urban Sites), a project whose objective is to develop an adaptable network robot architecture for cooperation between network robots and human beings and/or the environment in urban areas. The project goal is to deploy a team of robots in an urban area to give a set of services to a user community. This paper addresses the sensor architecture devised for URUS and the type of robots and sensors used, including environment sensors and sensors onboard the robots. Furthermore, we also explain how sensor fusion takes place to achieve urban outdoor execution of robotic services. Finally some results of the project related to the sensor network are highlighted.

A Multimodal Emotion Detection System during Human–Robot Interaction

In this paper, a multimodal user-emotion detection system for social robots is presented. This system is intended to be used during human–robot interaction, and it is integrated as part of the overall interaction system of the robot: the Robotics Dialog System (RDS). Two modes are used to detect emotions: the voice and face expression analysis. In order to analyze the voice of the user, a new component has been developed: Gender and Emotion Voice Analysis (GEVA), which is written using the Chuck language. For emotion detection in facial expressions, the system, Gender and Emotion Facial Analysis (GEFA), has been also developed. This last system integrates two third-party solutions: Sophisticated High-speed Object Recognition Engine (SHORE) and Computer Expression Recognition Toolbox (CERT). Once these new components (GEVA and GEFA) give their results, a decision rule is applied in order to combine the information given by both of them. The result of this rule, the detected emotion, is integrated into the dialog system through communicative acts. Hence, each communicative act gives, among other things, the detected emotion of the user to the RDS so it can adapt its strategy in order to get a greater satisfaction degree during the human–robot dialog. Each of the new components, GEVA and GEFA, can also be used individually. Moreover, they are integrated with the robotic control platform ROS (Robot Operating System). Several experiments with real users were performed to determine the accuracy of each component and to set the final decision rule. The results obtained from applying this decision rule in these experiments show a high success rate in automatic user emotion recognition, improving the results given by the two information channels (audio and visual) separately.

ISROBOTNET: A testbed for sensor and robot network systems

This paper introduces a testbed for sensor and robot network systems, currently composed of 10 cameras and 5 mobile wheeled robots equipped with several sensors for self-localization, obstacle avoidance and vision cameras, and wireless communications. The testbed includes a service-oriented middleware to enable fast prototyping and implementation of algorithms previously tested in simulation, as well as to simplify integration of subsystems developed by different partners. We survey an integrated approach to human-robot interaction that has been developed supported by the testbed under an European research project. The application integrates innovative methods and algorithms for people tracking and waving detection, cooperative perception among static and mobile cameras to improve people tracking accuracy, as well as decision-theoretical approaches to sensor selection and task allocation within the sensor network.

Selection of controller parameters using genetic algorithms

In this paper the problem of setting the initial values for tho parameters of a class of controllers is approached using genetic algorithms. The controller parameters, computed off-line via the optimization of a quadratic error performance index, can be used to initialize the controller incorporated in the real plant. During the on-line control stage and to increase the overall performance, other tuning mechanisms can be considered [5].

A robotic platform for edutainment activities in a pediatric hospital

Social Robotics is a rapidly expanding field of research, but long-term results in real-world environments have been limited. The MOnarCH project has the goal of studying the long-term social dynamics of networked robot systems in human environments. In this paper, we present the MOnarCH robotic platform to the research community. We discuss the constraints involved in the design and operation of our social robots, and describe in detail the platform that has been built to accomodate the project goals while satisfying those restrictions. We also present some preliminary results of the navigation methodologies that are used to control the MOnarCH robotic platforms.

Robust Covariance Estimation for Data Fusion From Multiple Sensors

This paper addresses the robust estimation of a covariance matrix to express uncertainty when fusing information from multiple sensors. This is a problem of interest in multiple domains and applications, namely, in robotics. This paper discusses the use of estimators using explicit measurements from the sensors involved versus estimators using only covariance estimates from the sensor models and navigation systems. Covariance intersection and a class of orthogonal Gnanadesikan-Kettenring estimators are compared using the 2-norm of the estimates. A Monte Carlo simulation of a typical mapping experiment leads to conclude that covariance estimation systems with a hybrid of the two estimators may yield the best results.

Transmission line inspection robots: Design of the power supply system

This work aims to develop a power supply system to use with the RIOL robot, [1], useful for inspecting high voltage overhead power lines. The power supply operating principle is based on the harvesting of the magnetic energy around the power supply lines by clamping a transformer around the line. A switching power rectifier, controlled to emulate a resistor, is then connected to the transformer secondary to obtain the robot needed voltages (55V ± 2.5%) and power (800W). Simulation results are presented and discussed.

New approaches for surveillance tasks

Abstract This paper describes part of a study on a prototype robot for monitoring/surveillance tasks conducted over the infrastructure provided by electric power lines/electric shield wires. Among the most relevant tasks that can be carried out by this robot are forest patrolling, environmental mapping and wildlife monitoring. The robot uses a statically stable variation of the brachistochrone motion to move along electric shield wires/electric power lines overcoming the standard obstacles. The paper describes the kinematics and basic simulation results on the dynamics and control of the robot.

Dynamical systems in robot control architectures: A building block perspective

The paper reviews a known robot control architecture using nonlinear analysis and control theory viewpoints. The architecture is based on a mesh of dynamic systems and feedthrough maps and is able to drive the robot under temporal constraints. The analysis points to an intuitive, though innovative, conclusion that control architectures can be constructed from a methodological perspective by mixing (i) dynamical systems with fixed points carefully selected to match mission requirements, and (ii) feedthrough maps that perform memoryless transformations on input data. Experiments using the Webots environment are presented to illustrate the ideas developed.

Hybrid control of semi-autonomous robots

This paper presents a hybrid architecture for robot control supported on basic concepts from the geometry of Hilbert spaces and nonsmooth calculus. The architecture develops in two classic layers. A supervising layer chooses which motion strategies to apply from a set contained in an execution layer. The paper focuses mainly in the lower execution layer, motivated by the control of semi-autonomous robots. A set of experiments on the control of unicycle robots is presented.