El tema general de esta Tesis Doctoral es navegación, guiado y control para Sistemas Aeroespacial... more El tema general de esta Tesis Doctoral es navegación, guiado y control para Sistemas Aeroespaciales Distribuidos (SAD). Los Satélites de Arquitectura Segmentada (SAS) son un tipo de SAD, donde dos o más satélites pequeños y simples, denominados segmentos, cumplen una función similar a la de un satélite monolítico tradicional. Algunos términos relacionados con SAS son: vuelo en formación, redes espaciales, instrumentos partidos y navegación en clúster, siendo éste último el tema particular de la presente investigación. Ésta propone centrarse en aspectos relacionados con la navegación relativa entre los segmentos, y su uso para el guiado y control de forma autónoma.
2013 IEEE 4th Latin American Symposium on Circuits and Systems (LASCAS), 2013
ABSTRACT A novel scheme for a CMOS low-voltage reference is proposed. It uses current subtraction... more ABSTRACT A novel scheme for a CMOS low-voltage reference is proposed. It uses current subtraction between the currents generated by two instances of the same current generator circuit, each one configured with different magnitude and temperature coefficients. Temperature stability is achieved owing to the partial compensation of the MOSFET threshold voltage and mobility temperature effects. For a nominal reference voltage of 436.5 mV, SPICE simulation reveals a ±38.2 ppm/°C temperature coefficient within the range of -20 °C to 100°C.
Resumen: Se implementa un algoritmo para la Trasformada Rápida de Fourier (FFT) en microcontrolad... more Resumen: Se implementa un algoritmo para la Trasformada Rápida de Fourier (FFT) en microcontroladores dsPIC y PIC32 mediante la reutilización software, lo cual permite disminuir el esfuerzo y el tiempo en programación. Los conocimientos necesarios para su implementación son mínimos por parte del programador, utilizándose librerías de funciones matemáticas y números complejos. Se busca generalizar el uso de los algoritmos de filtrado con los dispositivos genéricos utilizados. Se observa que la implementación de Filtros Lineales de Respuesta Finita (FIR) requiere menos cálculo computacional que la FFT. También se observa que existe una limitación en la longitud del vector donde se alojan los valores digitales provenientes de la operación de conversión analógica a digital. Para el caso de los PIC 32 esta longitud es de 512 y para los dsPIC es de 128. Es posible aumentar este número cambiando las condiciones de compilación y linkeo del simulador MPLAB. Los resultados obtenidos del hardw...
Intelligent Robots and Computer Vision XVIII: Algorithms, Techniques, and Active Vision, 1999
This work present one method aimed to individualization and recognition of vial signs in route an... more This work present one method aimed to individualization and recognition of vial signs in route and city. It is based fundamentally on the identification by means of color and form of the vial sing, located in the border of the route or street in city, and then recognition. To do so the obtained RGB image is processed, carrying out diverse filtrates in the sequence of input image, or intensifying the colors of the same ones otherwise, recognizing their silhouette and then segmenting the sign and comparing the symbology of them with the previously stored and classified database.
This work presents two real time models to provide statistical behaviour of an Ethernet link dela... more This work presents two real time models to provide statistical behaviour of an Ethernet link delays to use it in adaptive compensation of distributed close loop control systems. It has been obtained using an embedded Simulink model with xPCTarget toolbox on a standard PC. The model operates in asynchronous mode, and so there is not synchronization between the nodes. The measurements are indirect and they represent the behaviour of the network segment for use in a real system. UDP/IP is the protocol used.
A control system intended for AGV guidance in partially structured environments using 3D image pr... more A control system intended for AGV guidance in partially structured environments using 3D image processing is presented. A brief description of the recognition algorithms (using disparity) is given, as well as a detailed discussion of the control procedures that are proposed in the paper. Stability analysis for the control algorithms is also presented.
ABSTRACT The use of air bags in the presence of bad passenger and baby seat positions in car seat... more ABSTRACT The use of air bags in the presence of bad passenger and baby seat positions in car seats can injure or kill these individuals in case of an accident when this device is inflated. A proposed solution is the use of range sensors to detect passenger and baby seat risky positions. Such sensors allow the Airbag inflation to be controlled. This work is concerned with the application of different classification schemes to a real world problem and the optimization of a sensor as a function of the classification performance. The sensor is constructed using a new technology which is called Photo-Mixer-Device (PMD). A systematic analysis of the occupant detection problem was made using real and virtual environments. The challenge is to find the best sensor geometry and to adapt a classification scheme under the current technological constraints. Passenger head position detection is also a desirable issue. A couple of classifiers have been used into a simple configuration to reach this goal. Experiences and results are described.
IEEE Transactions on Control Systems Technology, 2010
We discuss the problem of automatic magnetic field compensation within an excluded volume where t... more We discuss the problem of automatic magnetic field compensation within an excluded volume where the magnetic field cannot be sensed in a direct way. Both magnetic field spatial average (shielding) and first order orthogonal gradients (shimming) are considered. The active shielding-shimming compensator is based on a multiple-input multiple-output controller driving a specifically designed coil-set. The magnetic field and its gradients are calculated from the readings of ten hall sensors located outside the exclusion volume.
The present work proposes an autonomous tracking control system and a control structure to combin... more The present work proposes an autonomous tracking control system and a control structure to combine autonomous and teleoperation commands in a bicycle-type mobile robot. This compounded operation renders great flexibility to the control system of the mobile robot. For autonomous operation, a simple tracking controller that includes compensation of the robot dynamics is developed. This tracking control system is proved to be stable in the sense that it asymptotically reaches the tracking objective. Teleoperation with visual access to the robot's workspace is integrated via a joystick with the autonomous operation of the robot. Simulations and experimental results on a prototype robot show the feasibility and performance of the proposed control system.
XII Argentine Symposium on Technology (AST 2011) (XL JAIIO, Córdoba, 29 de agosto al 2 de septiembre de 2011), 2011
A novel approach for the extrinsic calibration of a camerarobot system, i.e. the estimation of th... more A novel approach for the extrinsic calibration of a camerarobot system, i.e. the estimation of the pose of the camera with respect to the robot coordinate system, is presented. The method is based on the relative pose of a planar pattern as seen by the camera, estimated along a predefined set of simple robot motions. This set has been generated so as to exploit the kinematic constraints imposed by the robot architecture and the relative pose between the pattern and the camera coordinate system. The resulting calibration procedure is very simple, making it suitable to be used in a broad range of applications. Experimental evaluations on both synthetic and real data demonstrate the validity of the proposed method.
External visual interfaces for high precision measuring devices are based on the segmentation of ... more External visual interfaces for high precision measuring devices are based on the segmentation of images of their measuring reticle. In this paper, a method for subpixel straight lines detection is presented and tested on images taken from the reticle of a dark field autocollimator. The method has three steps, the sharpening of the image using a version of the Savitzky-Golay filter for smoothing and differentiation, the construction of a coarse edge image using Sobel filters, and finally, the subpixel edge location determination, by fitting a Gaussian function to orthogonal sections of the coarse edge image. We discuss results of applying the proposed method to images of the reticle of a Nikon 6D autocollimator, using the scale of the device as a benchmark for testing the error in the location of the lines and compare them with Sobel/Hough and Sobel/polynomial fitting. We report that for this type of image-content, Gaussian fitting has smaller uncertainty, when cameras with two different sensors are used.
A new descriptor model based on shape contour representation aimed to object recognition in non-s... more A new descriptor model based on shape contour representation aimed to object recognition in non-structured images is presented. The model uses the second derivative of the contour curve –a rotation invariant representationfor contour representation. A contour segmentation criterion suitable for form description is presented. An adaptation of this descriptor able to operate in scale-space is discussed. Some results are presented and further research work is proposed involving descriptor’s use in more complex problems.
2017 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2017
In this article we present a new method for measuring the misalignment distortion caused by the l... more In this article we present a new method for measuring the misalignment distortion caused by the lenses of the system used as a visual interface for a Nikon 6B autocollimator. This interface is used for making angle measurements using image processing techniques. This research paper studies the interaction between the optical systems of the interface's camera and the autocollimator. With the proposed method it is possible to quantify tolerances for the assembly process of the camera with the autocollimator. Furthermore, it is possible to quantify the contribution of the camera's misalignment induced by the environment (thermal gradients, for example) to the uncertainty in the autocollimator's scale calibration.
El tema general de esta Tesis Doctoral es navegación, guiado y control para Sistemas Aeroespacial... more El tema general de esta Tesis Doctoral es navegación, guiado y control para Sistemas Aeroespaciales Distribuidos (SAD). Los Satélites de Arquitectura Segmentada (SAS) son un tipo de SAD, donde dos o más satélites pequeños y simples, denominados segmentos, cumplen una función similar a la de un satélite monolítico tradicional. Algunos términos relacionados con SAS son: vuelo en formación, redes espaciales, instrumentos partidos y navegación en clúster, siendo éste último el tema particular de la presente investigación. Ésta propone centrarse en aspectos relacionados con la navegación relativa entre los segmentos, y su uso para el guiado y control de forma autónoma.
2013 IEEE 4th Latin American Symposium on Circuits and Systems (LASCAS), 2013
ABSTRACT A novel scheme for a CMOS low-voltage reference is proposed. It uses current subtraction... more ABSTRACT A novel scheme for a CMOS low-voltage reference is proposed. It uses current subtraction between the currents generated by two instances of the same current generator circuit, each one configured with different magnitude and temperature coefficients. Temperature stability is achieved owing to the partial compensation of the MOSFET threshold voltage and mobility temperature effects. For a nominal reference voltage of 436.5 mV, SPICE simulation reveals a ±38.2 ppm/°C temperature coefficient within the range of -20 °C to 100°C.
Resumen: Se implementa un algoritmo para la Trasformada Rápida de Fourier (FFT) en microcontrolad... more Resumen: Se implementa un algoritmo para la Trasformada Rápida de Fourier (FFT) en microcontroladores dsPIC y PIC32 mediante la reutilización software, lo cual permite disminuir el esfuerzo y el tiempo en programación. Los conocimientos necesarios para su implementación son mínimos por parte del programador, utilizándose librerías de funciones matemáticas y números complejos. Se busca generalizar el uso de los algoritmos de filtrado con los dispositivos genéricos utilizados. Se observa que la implementación de Filtros Lineales de Respuesta Finita (FIR) requiere menos cálculo computacional que la FFT. También se observa que existe una limitación en la longitud del vector donde se alojan los valores digitales provenientes de la operación de conversión analógica a digital. Para el caso de los PIC 32 esta longitud es de 512 y para los dsPIC es de 128. Es posible aumentar este número cambiando las condiciones de compilación y linkeo del simulador MPLAB. Los resultados obtenidos del hardw...
Intelligent Robots and Computer Vision XVIII: Algorithms, Techniques, and Active Vision, 1999
This work present one method aimed to individualization and recognition of vial signs in route an... more This work present one method aimed to individualization and recognition of vial signs in route and city. It is based fundamentally on the identification by means of color and form of the vial sing, located in the border of the route or street in city, and then recognition. To do so the obtained RGB image is processed, carrying out diverse filtrates in the sequence of input image, or intensifying the colors of the same ones otherwise, recognizing their silhouette and then segmenting the sign and comparing the symbology of them with the previously stored and classified database.
This work presents two real time models to provide statistical behaviour of an Ethernet link dela... more This work presents two real time models to provide statistical behaviour of an Ethernet link delays to use it in adaptive compensation of distributed close loop control systems. It has been obtained using an embedded Simulink model with xPCTarget toolbox on a standard PC. The model operates in asynchronous mode, and so there is not synchronization between the nodes. The measurements are indirect and they represent the behaviour of the network segment for use in a real system. UDP/IP is the protocol used.
A control system intended for AGV guidance in partially structured environments using 3D image pr... more A control system intended for AGV guidance in partially structured environments using 3D image processing is presented. A brief description of the recognition algorithms (using disparity) is given, as well as a detailed discussion of the control procedures that are proposed in the paper. Stability analysis for the control algorithms is also presented.
ABSTRACT The use of air bags in the presence of bad passenger and baby seat positions in car seat... more ABSTRACT The use of air bags in the presence of bad passenger and baby seat positions in car seats can injure or kill these individuals in case of an accident when this device is inflated. A proposed solution is the use of range sensors to detect passenger and baby seat risky positions. Such sensors allow the Airbag inflation to be controlled. This work is concerned with the application of different classification schemes to a real world problem and the optimization of a sensor as a function of the classification performance. The sensor is constructed using a new technology which is called Photo-Mixer-Device (PMD). A systematic analysis of the occupant detection problem was made using real and virtual environments. The challenge is to find the best sensor geometry and to adapt a classification scheme under the current technological constraints. Passenger head position detection is also a desirable issue. A couple of classifiers have been used into a simple configuration to reach this goal. Experiences and results are described.
IEEE Transactions on Control Systems Technology, 2010
We discuss the problem of automatic magnetic field compensation within an excluded volume where t... more We discuss the problem of automatic magnetic field compensation within an excluded volume where the magnetic field cannot be sensed in a direct way. Both magnetic field spatial average (shielding) and first order orthogonal gradients (shimming) are considered. The active shielding-shimming compensator is based on a multiple-input multiple-output controller driving a specifically designed coil-set. The magnetic field and its gradients are calculated from the readings of ten hall sensors located outside the exclusion volume.
The present work proposes an autonomous tracking control system and a control structure to combin... more The present work proposes an autonomous tracking control system and a control structure to combine autonomous and teleoperation commands in a bicycle-type mobile robot. This compounded operation renders great flexibility to the control system of the mobile robot. For autonomous operation, a simple tracking controller that includes compensation of the robot dynamics is developed. This tracking control system is proved to be stable in the sense that it asymptotically reaches the tracking objective. Teleoperation with visual access to the robot's workspace is integrated via a joystick with the autonomous operation of the robot. Simulations and experimental results on a prototype robot show the feasibility and performance of the proposed control system.
XII Argentine Symposium on Technology (AST 2011) (XL JAIIO, Córdoba, 29 de agosto al 2 de septiembre de 2011), 2011
A novel approach for the extrinsic calibration of a camerarobot system, i.e. the estimation of th... more A novel approach for the extrinsic calibration of a camerarobot system, i.e. the estimation of the pose of the camera with respect to the robot coordinate system, is presented. The method is based on the relative pose of a planar pattern as seen by the camera, estimated along a predefined set of simple robot motions. This set has been generated so as to exploit the kinematic constraints imposed by the robot architecture and the relative pose between the pattern and the camera coordinate system. The resulting calibration procedure is very simple, making it suitable to be used in a broad range of applications. Experimental evaluations on both synthetic and real data demonstrate the validity of the proposed method.
External visual interfaces for high precision measuring devices are based on the segmentation of ... more External visual interfaces for high precision measuring devices are based on the segmentation of images of their measuring reticle. In this paper, a method for subpixel straight lines detection is presented and tested on images taken from the reticle of a dark field autocollimator. The method has three steps, the sharpening of the image using a version of the Savitzky-Golay filter for smoothing and differentiation, the construction of a coarse edge image using Sobel filters, and finally, the subpixel edge location determination, by fitting a Gaussian function to orthogonal sections of the coarse edge image. We discuss results of applying the proposed method to images of the reticle of a Nikon 6D autocollimator, using the scale of the device as a benchmark for testing the error in the location of the lines and compare them with Sobel/Hough and Sobel/polynomial fitting. We report that for this type of image-content, Gaussian fitting has smaller uncertainty, when cameras with two different sensors are used.
A new descriptor model based on shape contour representation aimed to object recognition in non-s... more A new descriptor model based on shape contour representation aimed to object recognition in non-structured images is presented. The model uses the second derivative of the contour curve –a rotation invariant representationfor contour representation. A contour segmentation criterion suitable for form description is presented. An adaptation of this descriptor able to operate in scale-space is discussed. Some results are presented and further research work is proposed involving descriptor’s use in more complex problems.
2017 IEEE International Instrumentation and Measurement Technology Conference (I2MTC), 2017
In this article we present a new method for measuring the misalignment distortion caused by the l... more In this article we present a new method for measuring the misalignment distortion caused by the lenses of the system used as a visual interface for a Nikon 6B autocollimator. This interface is used for making angle measurements using image processing techniques. This research paper studies the interaction between the optical systems of the interface's camera and the autocollimator. With the proposed method it is possible to quantify tolerances for the assembly process of the camera with the autocollimator. Furthermore, it is possible to quantify the contribution of the camera's misalignment induced by the environment (thermal gradients, for example) to the uncertainty in the autocollimator's scale calibration.
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Papers by Luis Canali