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Publicações

Publicações por CRIIS

2013

IntellWheels: Intelligent wheelchair with user-centered design

Autores
Petry, MR; Moreira, AP; Faria, BM; Reis, LP;

Publicação
2013 IEEE 15th International Conference on e-Health Networking, Applications and Services, Healthcom 2013

Abstract
Intelligent wheelchairs can become an important solution to assist physically impaired individuals who find it difficult or impossible to drive regular powered wheelchairs. However, when designing the hardware architecture several projects compromise the user comfort and the wheelchair normal usability in order to solve robotic problems. In this paper we describe the main concepts regarding the design of the IntellWheels intelligent wheelchair. Our approach has a user-centered perspective, in which the needs and limitations of physically impaired users are given extensive attention at each stage of the design process. Finally, our design was evaluated through a public opinion assessment. A statistical analysis suggested that the design was effective to mitigate the visual and ergonomic impacts caused by the addition of sensorial and processing capabilities on the wheelchair. © 2013 IEEE.

2013

Object recognition using laser range finder and machine learning techniques

Autores
Pinto, AM; Rocha, LF; Paulo Moreira, AP;

Publicação
ROBOTICS AND COMPUTER-INTEGRATED MANUFACTURING

Abstract
In recent years, computer vision has been widely used on industrial environments, allowing robots to perform important tasks like quality control, inspection and recognition. Vision systems are typically used to determine the position and orientation of objects in the workstation, enabling them to be transported and assembled by a robotic cell (e.g. industrial manipulator). These systems commonly resort to CCD (Charge-Coupled Device) Cameras fixed and located in a particular work area or attached directly to the robotic arm (eye-in-hand vision system). Although it is a valid approach, the performance of these vision systems is directly influenced by the industrial environment lighting. Taking all these into consideration, a new approach is proposed for eye-on-hand systems, where the use of cameras will be replaced by the 2D Laser Range Finder (LRF). The LRF will be attached to a robotic manipulator, which executes a pre-defined path to produce grayscale images of the workstation. With this technique the environment lighting interference is minimized resulting in a more reliable and robust computer vision system. After the grayscale image is created, this work focuses on the recognition and classification of different objects using inherent features (based on the invariant moments of Hu) with the most well-known machine learning models: k-Nearest Neighbor (kNN), Neural Networks (NNs) and Support Vector Machines (SVMs). In order to achieve a good performance for each classification model, a wrapper method is used to select one good subset of features, as well as an assessment model technique called K-fold cross-validation to adjust the parameters of the classifiers. The performance of the models is also compared, achieving performances of 83.5% for kNN, 95.5% for the NN and 98.9% for the SVM (generalized accuracy). These high performances are related with the feature selection algorithm based on the simulated annealing heuristic, and the model assessment (k-fold cross-validation). It makes possible to identify the most important features in the recognition process, as well as the adjustment of the best parameters for the machine learning models, increasing the classification ratio of the work objects present in the robot's environment.

2013

Radiation tests on a bluetooth based front-end electronic device towards a subcutaneous continuous glucose monitoring sensor

Autores
Silva, S; Soares, S; Valente, A; Moreira, A;

Publicação
Proceedings of 2013 Science and Information Conference, SAI 2013

Abstract
The metabolic disorder which entails the absent or reduced control of blood glucose in the body by means of insulin dependence (Type 1) or intolerance (Type 2) affected more than 366 million people in 2011. This represents an increase of 28% new cases in one year. Diabetes Mellitus has become the most common chronic diseases in nearly all countries, and continues to increase in numbers and significance, as economic development and urbanization lead to changing lifestyles characterized by reduced physical activity, and increased obesity. Recent advances in wireless sensor networking technology have led to the development of low cost, low power, multifunctional sensor nodes that enable environment sensing together with data processing. Instrumented with a variety of sensors, such as temperature, humidity, volatile compound detection, bio implanted sensors; the development of such networks requires testing for transmission distance and human body interference. As Bluetooth Low-Energy (BLE) operates in the free 2.4GHz ISM band, the same band that Wi-Fi signals operate, tests regarding interference, robustness and coexistence must be made in order to ensure Quality of Service (QoS) and therefore achieve medical diagnostic equipment status. This paper presents a BLE prototype and compares the results obtained in terms of radiated power over distance with and without physical barriers. © 2013 The Science and Information Organization.

2013

Recognizing Industrial Manipulated Parts Using the Perfect Match Algorithm

Autores
Rocha, LF; Ferreira, M; Veiga, G; Moreira, AP; Santos, V;

Publicação
ROBOTICS IN SMART MANUFACTURING

Abstract
The objective of this work is to develop a highly robust 3D part localization and recognition algorithm. This research work is driven by the needs specified by enterprises with small production series that seek for full robotic automation in their production line, which processes a wide range of products and cannot use dedicated identification devices due to technological processes. With the correct classification of the part, the robot will be able to autonomously select the correct program to execute. For this purpose, the Perfect Match algorithm, which is known by its computational efficiency, high precision and robustness, was adapted for object recognition achieving a 99.7% of classification rate. The expected practical implication of this work is contributing to the integration of industrial robots in highly dynamic and specialized lines, reducing the companies' dependency on skilled operators.

2013

FEUPCAR 2.0: Overview of a Low-cost Robot for Autonomous Driving Competitions

Autores
Vidal, AA; Reis, LP; Paulo Moreira, AP;

Publicação
PROCEEDINGS OF THE 2013 8TH IBERIAN CONFERENCE ON INFORMATION SYSTEMS AND TECHNOLOGIES (CISTI 2013)

Abstract
Robotic autonomous driving is a very complex task that tries to replicate the human behavior when performing such task. This paper presents a high-level overview of an architecture applicable for small-scale vehicles in autonomous driving competitions. A special emphasis is given on the sensory and navigation sub-systems since they are the most prominent intelligent decision layers. The former is almost entirely based on computer vision, processing the raw image content from two ordinary and inexpensive "web-cams", conveying further relevant information to the later, on a real-time basis. The proposed architecture was implemented with minimal interventions to an Ackermann-like vehicle which was originally designed for recreational purposes, serving as a "proof of concept" of the developed system. Results show that a low-cost, scalable and modular system can be easily integrated on regular small-scale vehicles obtaining exciting results at a minimal cost.

2013

Intelligent state changing applied to multi-robot systems

Autores
Nascimento, TP; Moreira, AP; Conceicao, AGS; Bonarini, A;

Publicação
ROBOTICS AND AUTONOMOUS SYSTEMS

Abstract
The target searching problem is a situation where a formation of multi-robot systems is set to search for a target and converge towards it when it is found. This problem lies in the fact that the target is initially absent and the formation must search for it in the environment. During the target search, false targets may appear dragging the formation towards it. Therefore, in order to avoid the formation following a false target, this paper presents a new methodology using the Takagi-Sugeno type fuzzy automaton (TS-TFA) in the area of formation control to solve the target searching problem. The TS fuzzy system is used to change the formation through the modifications in the states of the automaton. This change does not only switch the rules and therefore the state of each robot, but also the controllers and cost functions. This approach amplifies the versatility of the formation of mobile robots in the target searching problem. In this paper, the TS-TFA is presented and its implications in the formation are explained. Simulations and results with real robot are presented where it can be noticed that the formation is broken to maximize the perception range based on each robot's observation of a possible target. Finally this work is concluded in the last section.

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