Hands-free wearable system for helping in assembly tasks in aerospace

Las operaciones de mantenimiento tienen un gran impacto en la seguridad y esperanza de vida de cualquier producto, especialmente en ciertas aplicaciones dentro de la industria aeronáutica que tiene que pasar procedimientos muy rigurosos de seguridad. Los sistemas de ayuda llevables (wearable) pueden ayudar a reducir costes y tiempo de trabajo guiando a los operarios en tareas difíciles. El propósito de este trabajo es presentar un sistema de guiado de manos libre y llevable para soporte y ayuda de operarios en tareas de ensamblaje y verificación dentro del campo de la aeronáutica. El operario es capaz de pedir información al sistema sobre una tarea específica de un modo no invasivo así como pedir asistencia técnica al líder del equipo. El sistema desarrollado ha sido probado en una compañía aeronáutica (Airbus Military) y se ha evaluado su implementación en ciertas tareas de ensamblaje. La conclusión de las pruebas ha sido que el sistema ayuda a los operarios a realizar sus tareas de una manera más rápida, precisa y segura.Maintenance operations have a great impact on the safety and life expectancy of any product. This is especially true for certain applications within the aerospace industry, which must pass rigorous security checking procedures. Wearable helping systems can help to reduce costs and working time by guiding workers in some specifi c and diffi cult tasks. The purpose of this work is developing a handless and wearable guided system that supports and helps workers in assembly and verifi cation tasks within the aeronautic fi eld. The worker is able to request information for the specifi c task in a non invasive way and also ask the Team Leader for real time technical support and assistance. The system developed has been tested in an aeronautic company (Airbus Military) and its implementation in specifi c assembly tasks assessed. It was found that the proposed system can help workers to make their tasks faster, more accurate and more secure

Rigid and Deformable Collision Handling for a Haptic Neurosurgery Simulator.

Simulation has been widely used for training and rehearsing difficult or unusual actions in several fields such as aviation and the military. However, the simulators available in some disciplines do not fulfil the requirements of reliability and accuracy that users demand. This happens in neurosurgery. In order to overcome these difficulties, this thesis presents a multimodal Neurosurgery Simulator focused on patient-specific surgical learning and training. One of the aspects that most influences the behavioural reality of a simulator is the way in which the scene objects interfere. For that reason, detecting collisions and giving them a feasible response is particularly important. This work presents the collision handling methods for rigid and deformable volumetric objects and their haptic response to be integrated into the Neurosurgery Simulator. With the aim of evaluating our methods in terms of continuity and stability, the present document analyses the time consumption of the collision handling algorithms and the stability of the force parameters they return. Real-time virtual reality simulators require accuracy but are also time dependent. Thus, their computational cost is a vital aspect. This thesis also proposes a methodology to optimize the time consumption of collision detection algorithms that are based on the uniform spatial partition technique. It is validated experimentally and compared to other approaches. Additionally, the optimization is applied to our deformable collision detection method in order to improve its performance

Improving the pipeline of an optical metrology system.

Metrology is one of the many applications of machine vision, which has the advantage that allows for the analyzing of a total production batch that leaves an assembly line without supposing a bottleneck. As a result, quality control become a priority in the inspection processes of industrial manufacturing. Due to the advancement of technology and the realizations of Industry 4.0, smart factories demand high precision and accuracy in the measurements and inspection of industrial products. Machine vision technology provide image-based inspection and analysis for such demanding applications. With the use of software, sensors, cameras and robot guidance, such integrated systems can be realized. Machine vision highlights a growing trend in industrial systems. As camera sensors become smarter, the quality of data produced offers accuracy into the systems operations. This thesis is a study of the typical vision system pipeline, in the different phases, necessary to achieve optimal inspection in an industrial operation. The first step is the study of the light alignment to monitor and achieve an optimal light alignment system, in order to eliminate the effects of misalignment. The algorithm was tested with a not-optimal system to ascertain its efficiency and effectiveness. In the second phase, a deep study of the calibration process is carried out to address the effect of different parameters as the camera focus among others. Endocentric and telecentric lenses are used in the image acquisition and a comparative analysis is obtained using a multivariable statistical analysis to study the influence of each parameter in the calibration process: camera focus, exposure time, calibration plate tilt and number of images used. In the third proposal, an object alignment algorithm is developed to address the challenge of object alignment during a measurement process. Object plane alignment is key point for achieving good repeatability of object measurements in all orientations. A complete study of the impact of every single pipeline phase is carried out in the proposals validation chapter. Finally, a complete 2D machine vision application is developed to determine the precise measurement of gears, at subpixel level, with the potential to improve quality control, reduce downtime and optimize the inspection process. The calibrated vision system was verified by measuring a ground-truth sample gear in a Coordinate Measuring Machine (CMM), using the parameter generated as the nominal value of the outer diameter. A methodical study of the global uncertainty associated with the process is carried out in order to know better the admissible zone for accepting gears. This thesis try to reach the optimal values in every single phase of the pipeline in order to improve the accuracy of the inspection. The different studies and algorithms developed in this thesis show that it is worthwhile to invest on achieving the optimal values during the different phases of an industrial inspection process.La metrología es una de las muchas aplicaciones de la visión artificial que tiene la ventaja de permitir el análisis dimensional de un lote completo de producción que sale de una línea de ensamblaje sin suponer un cuello de botella. Gracias a su potencial, el control de calidad se convierte en una prioridad en los procesos de inspección de la fabricación industrial. Debido al avance de la tecnología y el auge de la Industria 4.0, las fábricas inteligentes exigen alta precisión y exactitud en las mediciones e inspección de productos industriales. La tecnología de visión artificial proporciona inspección y análisis basados en imágenes. Con el uso de software, sensores, cámaras, ópticas, luminarias y guía de robots, estos sistemas integrados permiten realizar inspecciones flexibles, sin contacto y llegando en muchos casos al 100% de la producción. En esta tesis se analizan las diferentes fases del pipeline óptico clásico de un sistema de visión, estudiando las configuraciones que permiten optimizar la inspección. El primer paso es el estudio de la alineación lente-luz para monitorizar y lograr un sistema óptimo de alineación. El algoritmo se ha probado con diferentes configuraciones de alineamiento para determinar su efectividad. En la segunda fase del pipeline, se realiza un estudio profundo del proceso de calibración para abordar el efecto de diferentes parámetros como el enfoque de la cámara, tiempo de exposición y número e inclinación de las imágenes. Se realiza un análisis estadístico multivariable para estudiar la influencia de cada parámetro en el proceso de calibración. En la tercera propuesta, se desarrolla un algoritmo de alineación de objetos para abordar el problema de posibles desalineamientos durante un proceso de medición. En el capítulo de validación de propuestas se realiza un estudio completo del impacto de cada fase del pipeline. Los diferentes estudios y algoritmos desarrollados en esta tesis demuestran que merece la pena realizar la búsqueda de las configuraciones óptimas en cada fase del pipeline ya que se comprueba que hay mejora estadística en el proceso. Finalmente, se ha desarrollado una aplicación completa de visión artificial en 2D para determinar la medición precisa de engranajes, a nivel de subpíxeles, con el potencial de mejorar el control de calidad, reducir el tiempo de inactividad y optimizar el proceso de inspección. El sistema de visión calibrado se ha verificado midiendo un engranaje ground-truth en una máquina de medición de coordinadas (CMM), utilizando esta medida como valor nominal. Se ha llevado a cabo un estudio metódico de la incertidumbre global asociada con el proceso de medición

Rigid and Deformable Collision Handling for a Haptic Neurosurgery Simulator.

Simulation has been widely used for training and rehearsing difficult or unusual actions in several fields such as aviation and the military. However, the simulators available in some disciplines do not fulfil the requirements of reliability and accuracy that users demand. This happens in neurosurgery. In order to overcome these difficulties, this thesis presents a multimodal Neurosurgery Simulator focused on patient-specific surgical learning and training. One of the aspects that most influences the behavioural reality of a simulator is the way in which the scene objects interfere. For that reason, detecting collisions and giving them a feasible response is particularly important. This work presents the collision handling methods for rigid and deformable volumetric objects and their haptic response to be integrated into the Neurosurgery Simulator. With the aim of evaluating our methods in terms of continuity and stability, the present document analyses the time consumption of the collision handling algorithms and the stability of the force parameters they return. Real-time virtual reality simulators require accuracy but are also time dependent. Thus, their computational cost is a vital aspect. This thesis also proposes a methodology to optimize the time consumption of collision detection algorithms that are based on the uniform spatial partition technique. It is validated experimentally and compared to other approaches. Additionally, the optimization is applied to our deformable collision detection method in order to improve its performance

Rigid and Deformable Collision Handling for a Haptic Neurosurgery Simulator.

Simulation has been widely used for training and rehearsing difficult or unusual actions in several fields such as aviation and the military. However, the simulators available in some disciplines do not fulfil the requirements of reliability and accuracy that users demand. This happens in neurosurgery. In order to overcome these difficulties, this thesis presents a multimodal Neurosurgery Simulator focused on patient-specific surgical learning and training. One of the aspects that most influences the behavioural reality of a simulator is the way in which the scene objects interfere. For that reason, detecting collisions and giving them a feasible response is particularly important. This work presents the collision handling methods for rigid and deformable volumetric objects and their haptic response to be integrated into the Neurosurgery Simulator. With the aim of evaluating our methods in terms of continuity and stability, the present document analyses the time consumption of the collision handling algorithms and the stability of the force parameters they return. Real-time virtual reality simulators require accuracy but are also time dependent. Thus, their computational cost is a vital aspect. This thesis also proposes a methodology to optimize the time consumption of collision detection algorithms that are based on the uniform spatial partition technique. It is validated experimentally and compared to other approaches. Additionally, the optimization is applied to our deformable collision detection method in order to improve its performance

Study of Augmented Reality Methods for Real Time Recognition and Tracking of Untextured 3D Models in Monocular Images.

The main challenge of an augmented reality system is to obtain perfect alignment between real and virtual objects in order to create the illusion that both worlds coexist. To that end, the position and orientation of the observer has to be determined in order to configure a virtual camera that displays the virtual objects in their corresponding position. This problem is known as tracking, and although there are many alternatives to address it by using different sensors, tracking based on optical sensors is the most popular solution. However, optical tracking is not a solved problem. This thesis presents a study of the existing optical tracking methods and provides some improvements for some of them, particularly for those that are real time. More precisely, monocular optical marker tracking and model-based monocular optical markerless tracking are discussed in detail. The proposed improvements are focused on industrial environments, which is a difficult challenge due to the lack of texture in these scenes. Monocular optical marker tracking methods do not support occlusions, so this thesis proposes two alternatives: (1) a new tracking method based on temporal coherence, and (2) a new marker design. Both solutions are robust against occlusions and do not require more environment adaptation. Similarly, the response of model-based monocular optical markerless tracking methods is jeopardized in untextured scenes, so this thesis proposes a 3D object recognition method that uses geometric properties instead of texture to initialize the tracking, as well as a markerless tracking method that uses multiple visual cues to update the tracking. Additionally, the details of the augmented reality system that has been developed to help in disassembly operations are given throughout the thesis. This serves as a tool to validate the proposed methods and it also shows their real world applicability

Interacción en Sistemas Hápticos Multisensoriales: Respuesta de Colisión y Mejoras de Usabilidad

Las aplicaciones de Realidad Virtual son cada vez más frecuentes en áreas como la industria o la medicina ya que pueden utilizarse como herramientas de trabajo o de aprendizaje. La necesidad actual de que estos sistemas sean cada vez más realistas obliga a introducir el sentido del tacto aumentando de forma considerable la precisión y eficiencia con la que pueden desarrollarse las tareas además de la inmersión de los usuarios en este tipo de entornos. Los dispositivos hápticos permiten al usuario interactuar con objetos del entorno virtual a través del sentido del tacto percibiendo una respuesta de fuerza a cualquier colisión con el entorno. Sin embargo, esta tecnología háptica es todavía reciente lo que no permite obtener una respuesta estable y realista en casos complejos. La presente Tesis investiga y ofrece soluciones en dos áreas fundamentales de la háptica: el cálculo de las fuerzas y pares de contacto como resultado de las acciones de los usuarios en entornos virtuales y la percepción multisensorial. La detección y respuesta de colisión en tiempo real es una tarea complicada y esencial para la efectividad de estos sistemas hápticos. Este trabajo desarrolla un método de renderizado háptico capaz de calcular una respuesta háptica estable y agradable incluso en situaciones complejas tales como las tareas de desensamblado en entornos aeronáuticos. Además, se analiza la eficacia de combinar los distintos canales sensoriales disponibles para mejorar la percepción global del sistema así como la inmersión final del usuario

Study of Augmented Reality Methods for Real Time Recognition and Tracking of Untextured 3D Models in Monocular Images.

The main challenge of an augmented reality system is to obtain perfect alignment between real and virtual objects in order to create the illusion that both worlds coexist. To that end, the position and orientation of the observer has to be determined in order to configure a virtual camera that displays the virtual objects in their corresponding position. This problem is known as tracking, and although there are many alternatives to address it by using different sensors, tracking based on optical sensors is the most popular solution. However, optical tracking is not a solved problem. This thesis presents a study of the existing optical tracking methods and provides some improvements for some of them, particularly for those that are real time. More precisely, monocular optical marker tracking and model-based monocular optical markerless tracking are discussed in detail. The proposed improvements are focused on industrial environments, which is a difficult challenge due to the lack of texture in these scenes. Monocular optical marker tracking methods do not support occlusions, so this thesis proposes two alternatives: (1) a new tracking method based on temporal coherence, and (2) a new marker design. Both solutions are robust against occlusions and do not require more environment adaptation. Similarly, the response of model-based monocular optical markerless tracking methods is jeopardized in untextured scenes, so this thesis proposes a 3D object recognition method that uses geometric properties instead of texture to initialize the tracking, as well as a markerless tracking method that uses multiple visual cues to update the tracking. Additionally, the details of the augmented reality system that has been developed to help in disassembly operations are given throughout the thesis. This serves as a tool to validate the proposed methods and it also shows their real world applicability