Browsing by Author "Costa, Paulo Gomes da"
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- 2D cloud template matching - a comparison between iterative closest point and perfect matchPublication . Sobreira, Héber; Rocha, Luís Freitas; Costa, Carlos M.; Lima, José; Costa, Paulo Gomes da; Moreira, António Paulo G. M.Self-localization of mobile robots in the environment is one of the most fundamental problems in the robotics field. It is a complex and challenging problem due to the high requirements of autonomous mobile vehicles, particularly with regard to algorithms accuracy, robustness and computational efficiency. In this paper we present the comparison of two of the most used map-matching algorithm, which are the Iterative Closest Point and the Perfect Match. This category of algorithms are normally applied in localization based on natural landmarks. They were compared using an extensive collection of metrics, such as accuracy, computational efficiency, convergence speed, maximum admissible initialization error and robustness to outliers in the robots sensors data. The test results were performed in both simulated and real world environments.
- 3D Simulator based on simTwo to evaluate algorithms in micromouse competitionPublication . Eckert, Lucas; Piardi, Luis; Lima, José; Costa, Paulo Gomes da; Valente, António; Nakano, Alberto YoshiroRobotics competitions are increasing in complexity and number challenging the researchers, roboticists and enthusiastic to address the robot applications. One of the well-known competition is the micromouse where the fastest mobile robot to solve a maze is the winner. There are several topics addressed in this competition such as robot prototyping, control, electronics, path planning, optimization, among others. A simulation can be used to speed-up the development and testing algorithms but faces the gap between the reality in the dynamics behaviour. In this paper, an open source realistic simulator tool is presented where the dynamics of the robot, the slippage of the wheels, the friction and the 3D visualization can be found. The complete simulator with the robot model and an example is available that allow the users to test, implement and change all the environment. The presented results validate the proposed simulator.
- 3D Simulator with hardware-in-the-loop capability for the micromouse competitionPublication . Piardi, Luis; Eckert, Lucas; Lima, José; Costa, Paulo Gomes da; Valente, António; Nakano, Alberto YoshiroRobotics competitions are a way to challenge researchers, roboticists and enthusiastic to address robot applications. One of the well-known international competition is the Micromouse where the fastest mobile robot to solve a maze is the winner. There are several topics addressed in this competition such as robot prototyping, control, electronics, path planning, optimization, among others while keeping the size of the robot as small as possible. A simulation can be used to speed-up the development and testing algorithms but faces the gap between a simulation and reality, specially in the dynamics behaviour. There are some simulation environments that allow to simulate the Micromouse competition, but in this paper, an Hardware-in-the-loop simulator tool is presented where the simulated robot is controlled by the same microcontroller used by the robot. By this way, the developed algorithms are tested and validated with the limitations and constraints presented in the real hardware, such as memory and processing capabilities. The robot dynamics, the slippage of the wheels, the friction and the 3D visualization are present in the simulator. The presented results show that the same code and hardware controlling the simulated and the real robot identically.
- A* search algorithm optimization path planning in mobile robots scenariosPublication . Lima, José; Costa, Pedro; Costa, Paulo Gomes da; Eckert, Lucas; Piardi, Luis; Moreira, António Paulo G. M.; Nakano, Alberto YoshiroPath planning for mobile robotics in unknown environments or with moving obstacles requires re-planning paths based on information gathered from the surroundings. Moving obstacles and real time constraints require fast computing to navigate and make decisions in a mobile robot. This paper addresses an optimization approach to compute, with real time constraints, the optimal path for a mobile robot based on a dynamically simplified A* search algorithm with a commitment on the available time.
- An AI-based object detection approach for robotic competitionsPublication . Pilarski, Leonardo; Luiz, Luiz Eduardo; Braun, João; Nakano, Alberto Yoshiro; Pinto, Vítor H.; Costa, Paulo Gomes da; Lima, JoséArtificial Intelligence has been introduced in many applications, namely in artificial vision-based systems with object detection tasks. This paper presents an object localization system with a motivation to use it in autonomous mobile robots at robotics competitions. The system aims to allow robots to accomplish their tasks more efficiently. Object detection is performed using a camera and artificial intelligence based on the YOLOv4 Tiny detection model. An algorithm was developed that uses the data from the system to estimate the parameters of location, distance, and orientation based on the pinhole camera model and trigonometric modelling. It can be used in smart identification procedures of objects. Practical tests and results are presented, constantly locating the objects and with errors between 0.16 and 3.8 cm, concluding that the object localization system is adequate for autonomous mobile robots.
- An industry 4.0 approach for the Robot@Factory lite competitionPublication . Lima, José; Oliveira, Vitor; Brito, Thadeu; Gonçalves, José; Pinto, Vítor H.; Costa, Paulo Gomes da; Torrico, CesarThe Robot@Factory Lite (R@FL) is a competition held at the Portuguese Robotics Open that aims to present a problem inspired by the deployment of autonomous mobile robots on a factory shop floor. This paper proposes an approach to transform this competition according to the Industry 4.0 concept using the Wi-Fi to attribute orders to the mobile robot. The main contribution of this paper is to address a Supply Chain Management (SPM) of the ERP (Enterprise Resource Planning) that will inform the tasks to the robot so that it can schedule. It is presented a new hardware architecture that should be able to read the information of the parts through Wi-Fi in a client-server methodology. It also includes encoders that allow to feedback the wheels rotation and can be used to estimate the odometry.
- An optimization approach for the inverse kinematics of a highly redundant robotPublication . Costa, Paulo Gomes da; Lima, José; Pereira, Ana I.; Costa, Pedro; Pinto, AndryThis paper describes a robot with 12 degrees of freedom for pick-and-place operations using bricks. In addition, an optimization approach is proposed, which determines the state of each joint (that establishes the pose for the robot) based on the target position while minimizing the effort of the servomotors avoiding the inverse kinematics problem, which is a hard task for a 12 DOF robot manipulator. Therefore, it is a multi-objective optimization problem that will be solved using two optimization methods: the Stretched Simulated Annealing method and the NSGA II method. The experiments conducted in a simulation environment prove that the proposed approach is able to determine a solution for the inverse kinematics problem. A real robot formed by several servomotors and a gripper is also presented in this research for validating the solutions.
- Automated ceramics tableware finishing: a laboratory prototype for concept validationPublication . Alvarez, Mariano Jose; Brancalião, Laiany; Carneiro, Jorge; Costa, Paulo Gomes da; Coelho, João Paulo; Gonçalves, JoséIn this paper, it is presented an integration between a finishing device and a collaborative robot in order to automate the sanding process of a ceramic industry in Portugal. The finishing device and the collaborative robot are described as well as the communication between the devices. It was used a computer responsible for decision making and control of all the system. The system was able to control the position of the finishing device according to the force done in the sponge by the ceramic. The final system behavior was presented and discussed, which was satisfactory and performed well. The presented experimental setup is not intended for industrial use, but it is suitable for concept prove, in laboratory. The outputs that will emerge here will be applied in a future industrial application, with requisites compatible with the application environment, regarding robustness and repeatability.
- Automated ceramics tableware finishing: non-circular geometries case studyPublication . Alvarez, Mariano Jose; Brancalião, Laiany Suganuma; Carneiro, Jorge; Costa, Paulo Gomes da; Coelho, João Paulo; Gonçalves, JoséThis paper is devoted to present the most recent results regarding the ongoing work carried out in the scope of the STC 4.0 HP project, which aims to automate the finishing process of ceramic tableware at the GRESTEL S.A. industry, focusing on non-circular shaped plates. A collaborative robot is in charge of handling the tableware and making it go around its entire perimeter through a sponge, to perform the finishing. An array, with the distances from the center to the different points of the plate, is applied as data to trace the path that the robot must follow. The final goal of this prototype is to obtain an even finish while maintaining a constant force along the entire perimeter of the ceramic tableware. After carrying out a series of tests, it was possible to conclude that the current approach was able to manipulate 3D-printed tableware made for testing and travel its perimeter to carry out the finishing.
- Ball and beam virtual laboratory: a teaching aid in automatic control coursesPublication . Lima, José; Gonçalves, José; Costa, Paulo Gomes da; Moreira, António Paulo G. M.This paper describes a humanoid robot simulator with realistic dynamics. As simulation is a powerful tool for speeding up the control software development, the suggested accurate simulator allows to accomplish this goal. The simulator, based on the Open Dynamics Engine and GLScene graphics library, provides instant visual feedback and allows the user to test any control strategy without damaging the real robot in the early stages of the development. The proposed simulator also captures some characteristics of the environment that are important and allows to test controllers without access to the real hardware. Experimental results are shown that validate this approach.