Manuel Mazo Quintas

Improvements of a Brain-Computer Interface Applied to a Robotic Wheelchair

Two distinct signal features suitable to be used as input to a Support-Vector Machine (SVM) classifier in an application involving hands motor imagery and the correspondent EEG signal are evaluated in this paper. Such features are the Power Spectral Density (PSD) components and the Adaptive Autoregressive (AAR) parameters. The best result (an accuracy of 97.1%) is obtained when using PSD components, while the AAR parameters generated an accuracy of 91.4%. The results also demonstrate that it is possible to use only two EEG channels (bipolar configuration around C 3 and C 4), discarding the bipolar configuration around C z . The algorithms were tested with a proprietary EEG data set involving 4 individuals and with a data set provided by the University of Graz (Austria) as well. The resulting classification system is now being implemented in a Brain-Computer Interface (BCI) used to guide a robotic wheelchair.

Optimum conditioning of PbSe photoconductive detectors in measurements without chopping

This paper analyses the most important sources of uncertainty in the circuitry of an infrared radiation measurement system without chopping based on PbSe photoconductive detectors. It studies the influence of the conditioning system on noise and thermal drift, proposing two optimum diagrams depending on the effect to be minimised. Finally, a study of the noise and drift in a complete circuit is carried out, demonstrating the effects generated by the circuitry which may limit the final precision of the system. The overall results obtained demonstrate that with a suitable design the undesired effects of the conditioning circuitry can be kept at acceptable levels for a good number of applications.

Simultaneous localization and structure reconstruction of mobile robots with external cameras

This paper presents a way to achieve robot positioning using visual information from cameras placed in the environment. The goal is to obtain both the global position and a not fixed amount of features from the robot. There is a defined algorithm that implements 3D reconstruction at the same time the position of the robot is updated. The problem statement is equivalent to visual SLAM process and therefore all definitions are made in a top-down Bayesian process. This document presents a novel study of robot positioning simultaneous with 3D reconstruction, with one camera and unknown robot landmarks, which is easily expanded to a multicamera process. Its assumed that odometric information is always present in the system, so it is used in both estimation and initialization phases.

Infrared temperature measurement system using photoconductive PbSe sensors without radiation chopping

This paper proposes an infrared temperature measurement system based on a PbSe photoconductive sensor that enables a high quality measurement to be obtained without chopping the radiation. The main problems that arise from eliminating chopping are analysed and the solutions adopted in order to reduce their effect are described. The quality of the measurement obtained using the system is quantified for a real application and is compared with other contributions that are independent of whether radiation chopping is performed or not.

Guidance of Autonomous Vehicles by Means of Structured Light

Abstract This paper describes a system comprising a CCD sensor coupled with an infra-red emitter so that the emission of structured light then captured in the sensor CCD (vision angle 90°) gives the 3-D co-ordinates of the light impact points. Working from the co-ordinate matrix supplied, surrounding obstacles and vacant areas can be detected. The environment through which the robot may move is generated considering its dimensions and orientation. A check is made in the latest environment update of whether any obstacles balk the objective. If so, the path is varied so that the obstacle is avoided and the path optimum.

Vigilance system in rails for train hot point temperatures during circulation

Wheels, hubs and brake discs in a train during its circulation are under mechanical strains that make its temperature increase above the environment temperature. Mechanical defects in those elements produce an excessive friction and, as a consequence of it, an important increment of its temperature in relation to normal values. Detecting these anomalies is essential to avoid accidents and it is performed by fixed systems located next to rails which make infrared temperature measurements of hot points and send them to a supervisory station that takes the proper steps. The paper introduces the most important problems which must be dealt with during the designing stage of the measurement system. It also explains the solutions taken by the authors in order to assure the minimum operative aims demanded by the application. These problems includes: the choice of the detector and measurement method, communication with the supervisory station, and the environment conditions. Finally, the research lines followed by the authors in order to improve and extend the systems capabilities are explained.

Main limitations in infrared temperature measurement of train hot points

Nowadays, in order to guarantee the security in passenger and goods railway transport, fixed systems located in rails are used to measure axles, wheels and brake discs temperatures during train circulation so that abnormally high temperatures as a result of a malfunction can be detected. Measurement systems in this kind of application may be affected by different uncertainty sources, characteristic of infrared temperature measurements, which limit the accuracy of the estimated measurement. Uncertainty sources are specially important in these applications due to:Nowadays, in order to guarantee the security in passenger and goods railway transport, fixed systems located in rails are used to measure axles, wheels and brake discs temperatures during train circulation so that abnormally high temperatures as a result of a malfunction can be detected. Measurement systems in this kind of application may be affected by different uncertainty sources, characteristic of infrared temperature measurements, which limit the accuracy of the estimated measurement. Uncertainty sources are specially important in these applications due to: (1) Extremely variable emissivity as a result of stain or different paints used on the surfaces. (2) Difficult evaluation of the environments radiation as measurements are made outdoors. (3) Alarm temperatures are only about 40 degrees Celsius to 80 degrees Celsius above the environment temperature. The paper analyses the effects of these uncertainties. The results show that, in order to get the minimum uncertainty peaks in the estimated temperature, the proper duty waveband is 3 - 5 micrometer. They also show that, with a proper choice of the wavelength, the uncertainty due to solar radiation remains masked by the uncertainty due to the lens emissivity.