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Publications

Publications by Paulo José Costa

2021

Design, Modeling, and Control of an Autonomous Legged-Wheeled Hybrid Robotic Vehicle with Non-Rigid Joints

Authors
Pinto, VH; Soares, IN; Rocha, M; Lima, J; Goncalves, J; Costa, P;

Publication
APPLIED SCIENCES-BASEL

Abstract
This paper presents a legged-wheeled hybrid robotic vehicle that uses a combination of rigid and non-rigid joints, allowing it to be more impact-tolerant. The robot has four legs, each one with three degrees of freedom. Each leg has two non-rigid rotational joints with completely passive components for damping and accumulation of kinetic energy, one rigid rotational joint, and a driving wheel. Each leg uses three independent DC motors-one for each joint, as well as a fourth one for driving the wheel. The four legs have the same position configuration, except for the upper hip joint. The vehicle was designed to be modular, low-cost, and its parts to be interchangeable. Beyond this, the vehicle has multiple operation modes, including a low-power mode. Across this article, the design, modeling, and control stages are presented, as well as the communication strategy. A prototype platform was built to serve as a test bed, which is described throughout the article. The mechanical design and applied hardware for each leg have been improved, and these changes are described. The mechanical and hardware structure of the complete robot is also presented, as well as the software and communication approaches. Moreover, a realistic simulation is introduced, along with the obtained results.

2020

Environment Monitoring Modules with Fire Detection Capability Based on IoT Methodology

Authors
Brito, T; Azevedo, BF; Valente, A; Pereira, AI; Lima, J; Costa, P;

Publication
Science and Technologies for Smart Cities - 6th EAI International Conference, SmartCity360° Virtual Event, December 2-4, 2020, Proceedings

Abstract
Worldwide, forests have been devastated by fires in recent years. Whe- ther by human intervention or for other reasons, the history of burned areas is increasing year after year, degrading fauna and flora. For this reason, it is vital to detect an early ignition so that firefighters can act quickly, reducing the impacts caused by forest fires. The proposed system aims to improve the nature monitoring and to assist the existing surveillance systems through Wireless Sensor Network. The network formed by the set of sensors has the potential to identify forest ignitions and, consequently, alerts the authorities through LoRaWAN communication. This work presents a prototype based on low-cost technology, which can be used in areas that require a high density of modules. Tests with a Wireless Sensor Network made up of nine prototypes demonstrate its effectiveness and robustness in terms of data transmission and collection. In this way, it is possible to apply this approach in Portuguese forests with a high level of forest fire risk, transforming them into Forests 4.0 concept.

2021

Improving a position controller for a robotic joint

Authors
Moreira, AP; Lima, J; Costa, P;

Publication
2021 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC)

Abstract
There are several industrial processes that are controlled by a PID or similar controller. In robotics it is also usual the need of position control of joints. Tune a controller is the process to obtain the gains that optimise the behaviour of the system while maintaining its stability and robustness. This paper presents an approach of tuning a speed controller using the Internal Model Control (IMC) method and a position controller using the second order Bessel prototype while testing in different controllers methodology, such as PID, Cascade and feedforward combination with dead zone compensation. In order to compare the controllers, results for an Hermite reference position will allow to validate the proposed solution.

2021

IMU calibration for state estimation of an over-sensored low-cost robotic manipulator

Authors
Moreira, J; Pinto, VH; Costa, P;

Publication
2021 IEEE INTERNATIONAL CONFERENCE ON AUTONOMOUS ROBOT SYSTEMS AND COMPETITIONS (ICARSC)

Abstract
There are currently several techniques for automatic calibration of inertial sensors. This paper describes a subset of these algorithms that could be used in a manipulator and should allow for its prompt use. A robotic manipulator specifically developed for the study of over-sensored systems is used to realistically test the performance of the implemented methods. The results of these methods show that the accelerometers and the gyroscopes were properly calibrated. However, the magnetometers suffer from variable interferences and therefore could not be calibrated.

2020

Indoor Environment Monitoring in Search of Gas Leakage by Mobile Robot

Authors
Braun, J; Piardi, L; Brito, T; Lima, J; Pereira, A; Costa, P; Nakano, A;

Publication
FOURTH IBERIAN ROBOTICS CONFERENCE: ADVANCES IN ROBOTICS, ROBOT 2019, VOL 2

Abstract
Inspection based on mobile autonomous robots can assume an important role in many industries. Instead of having fixed sensors, the concept of assembling the sensors on a mobile robot that performs the scanning and inspection through a defined path is cheaper, configurable and adaptable. This paper describes a mobile robot, equipped with several gas sensors and a LIDAR device, that scans an established area by following a trajectory based on way-points searching for gas leakage and simultaneously avoid obstacles in the map. In other words, the robot follows the trajectory while the gas concentration is under a defined value and surrounding the obstacles. Otherwise, the autonomous robot starts the leakage search based on a search algorithm that allows to find the leakage position. The proposed methodology is verified in simulation based on a model of the real robot. The search test performed in a simulation environment allows to validate the proposed methodology.

2021

Searching the Optimal Parameters of a 3D Scanner Through Particle Swarm Optimization

Authors
Braun J.; Lima J.; Pereira A.I.; Rocha C.; Costa P.;

Publication
Communications in Computer and Information Science

Abstract
The recent growth in the use of 3D printers by independent users has contributed to a rise in interest in 3D scanners. Current 3D scanning solutions are commonly expensive due to the inherent complexity of the process. A previously proposed low-cost scanner disregarded uncertainties intrinsic to the system, associated with the measurements, such as angles and offsets. This work considers an approach to estimate these optimal values that minimize the error during the acquisition. The Particle Swarm Optimization algorithm was used to obtain the parameters to optimally fit the final point cloud to the surfaces. Three tests were performed where the Particle Swarm Optimization successfully converged to zero, generating the optimal parameters, validating the proposed methodology.

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