Dynamic alignment and calibration of linear axes

Linear positioning axes are used as basic assemblies in a wide range of applications in manufacturing, and measurement technology, such as in machine tools and coordinate measuring machines. If linear axes are installed in machines and devices, the accuracy of the complete system is limited by the rotational and translatory deviations of the individual axes from the ideal linear path of motion. The highly accurate, dynamic detection of the guiding properties during mounting and alignment of these system components is consequently the key to achieving minimal positioning deviations of the assembled system. The presented devices for the alignment and calibration of linear axes are based on laser interferometric measuring methods. They enable highly accurate simultaneous measurements of linear position, pitch and yaw angles as well as a straightness component in one measurement run

Snapshot spectral imaging using image replication and birefringent interferometry : principles and applications

This thesis explores the image-replicating imaging spectrometer (IRIS). This relatively recent invention is a two-dimensional, snapshot spectral-imaging technology, capable of recording the spectral and spatial data from a scene instantaneously. Whereas conventional spectral-imaging technologies require multiple detector frames to record the entire data set, IRIS is able to record the data set in a single frame, a capability which is useful for highly dynamic scenes. The IRIS concept and the design of IRIS systems are explained in detail, and constraints on the performance of IRIS are determined. Practical issue in the use of IRIS systems are identi ed and solutions are identi ed and appraised. Some applications of IRIS are also shown, demonstrating its viability as a spectral imaging technology. Novel aspects of this work include the re nement of the IRIS design, demonstration of a registration algorithm for IRIS, designs for achromatic Wollaston prisms, a comparison of the IRIS technology with conventional spectral imaging technologies, and the application of IRIS to practical problems.Engineering and Physical Sciences Research Council (EPSRC)Selex Galile

Traceability of on-machine tool measurement: a review

Nowadays, errors during the manufacturing process of high value components are not acceptable in driving industries such as energy and transportation. Sectors such as aerospace, automotive, shipbuilding, nuclear power, large science facilities or wind power need complex and accurate components that demand close measurements and fast feedback into their manufacturing processes. New measuring technologies are already available in machine tools, including integrated touch probes and fast interface capabilities. They provide the possibility to measure the workpiece in-machine during or after its manufacture, maintaining the original setup of the workpiece and avoiding the manufacturing process from being interrupted to transport the workpiece to a measuring position. However, the traceability of the measurement process on a machine tool is not ensured yet and measurement data is still not fully reliable enough for process control or product validation. The scientific objective is to determine the uncertainty on a machine tool measurement and, therefore, convert it into a machine integrated traceable measuring process. For that purpose, an error budget should consider error sources such as the machine tools, components under measurement and the interactions between both of them. This paper reviews all those uncertainty sources, being mainly focused on those related to the machine tool, either on the process of geometric error assessment of the machine or on the technology employed to probe the measurand

Lens-free interferometric microscope for transparent materials

As health systems fight against epidemics and infectious diseases, new forms of diagnostics need to be developed in order to meet the growing demand for services, often in locations without the necessary infrastructure. An emerging solution to this problem is point of care (POC) devices since they can provide rapid diagnostics without the need for specialized personnel or complex infrastructures. In this thesis, we show the development of a POC platform for the rapid early detection of infection, in particular Sepsis, a whole-body inflammatory reaction with high mortality rates. The main components of this platform are: a lens-free interferometric microscope (LIM) and a microfluidic cartridge with a functionalized plasmonic chip for the label-free detection of biomarkers. The LIM is also able to measure the phase modulation in commercial plasmonic chips. More specifically the thesis describes: • The development of a LIM with a large field of view and depth of field showing a sensitivity of 1nm along the beam propagation axis, which allows, for instance, the measurements of ultra-thin (2nm thickness) transparent silica and protein monolayer microarrays. • The generation of periodic structured light beams, obtained using a simple configuration including the birefringent elements of the LIM. These can be applied not only to imaging and biomarker detection but also in additive manufacturing and micro-structuring of surfaces. • The phase measurement of commercial surface plasmon resonance chips for the detection of changes in the refractive index of liquids. The phase measurements provide a sensitivity for bulk refractive index changes that is about one order of magnitude larger than for intensity-based detection under similar conditions. These results show a potential enhancement of the sensitivity of standard systems used in the biomedical community. • The development of a POC device comprising the LIM as a reader of specifically designed plasmonic gold nanohole array chips. The reading of the phase signal in the LIM shows a sensitivity increased by one order of magnitude thanks to the enhanced localized surface plasmon resonance interaction. Low concentrations of proteins and bacteria (as low as a single unit) are detected in measurements that also include human samples. This platform has the potential to multiplex the signal for simultaneous detection of thousands or even millions of different biomarkers. The LIM presented in this thesis is a very sensitive and robust imaging system with a high performance level for the detection of small quantities of transparent materials, with applications in microscopy and biomedicine.A medida que los sistemas de salud combaten epidemias y enfermedades infecciosas, nuevas formas de diagnóstico deben desarrollarse para satisfacer la creciente demanda de servicios, a menudo en lugares sin la infraestructura necesaria. Una solución emergente a este problema son los dispositivos de punto de atención (POC por sus siglas en inglés) ya que pueden proporcionar un diagnóstico rápido sin la necesidad de personal especializado o infraestructura compleja. En esta tesis mostramos el desarrollo de una plataforma POC para la detección rápida y temprana de infecciones, en particular Sepsis, una reacción inflamatoria de todo el cuerpo con altas tasas de mortalidad. Los principales componentes de esta plataforma son: un microscopio interferométrico sin lentes (LIM por sus siglas en inglés) y un cartucho de microfluídica con un chip plasmónico funcionalizado para la detección de biomarcadores, libre de marcadores adicionales. El LIM es también capaz de medir la modulación de fase en chips plasmónicos comerciales. Más específicamente, la tesis describe: * El desarrollo del LIM con un gran campo de visión y profundidad de campo mostrando una sensibilidad de 1nm a lo largo del eje de propagación del haz, que permite, por ejemplo, las mediciones de microarreglos ultrafinos (grosor de 2nm) y transparentes de Sílica y de monocapas de proteína.* La generación de haces de luz estructurados periódicos, obtenidos usando una configuración simple que incluye los elementos birrefringentes del LIM. Estos pueden ser aplicados no sólo a la detección de imágenes y biomarcadores, sino también a la fabricación aditiva y microestructuración de superficies. * La medición de fase en chips comerciales por resonancia de plasmón superficial para la detección de cambios en el índice de refracción de líquidos. Las mediciones de fase proporcionan una sensibilidad para cambios de índice de refracción en bulto que es aproximadamente un orden de magnitud mayor que para la detección basada en la intensidad con condiciones similares. Estos resultados muestran una potencial mejora de la sensibilidad de los sistemas estándar utilizados en la comunidad biomédica. * El desarrollo de un dispositivo POC que comprende el LIM como lector de chips plasmónicos de oro con arreglos de nano-agujeros específicamente diseñados. La lectura de la señal de fase en el LIM muestra un aumento de un orden de magnitud en la sensibilidad gracias a la interacción mejorada por la resonancia de plasmón superficial localizado. Bajas concentraciones de proteínas y bacterias (tan bajas como una sola bacteria) se detectan en mediciones que también incluyen muestras humanas. Esta plataforma tiene el potencial de multiplexar la señal para la detección simultánea de miles o incluso millones de biomarcadores diferentes. El LIM presentado en esta tesis es un sistema de imagen muy sensible y robusto con un alto nivel de rendimiento para la detección de pequeñas cantidades de materiales transparentes, con aplicaciones en microscopía y biomedicina

Lens-free interferometric microscope for transparent materials

As health systems fight against epidemics and infectious diseases, new forms of diagnostics need to be developed in order to meet the growing demand for services, often in locations without the necessary infrastructure. An emerging solution to this problem is point of care (POC) devices since they can provide rapid diagnostics without the need for specialized personnel or complex infrastructures. In this thesis, we show the development of a POC platform for the rapid early detection of infection, in particular Sepsis, a whole-body inflammatory reaction with high mortality rates. The main components of this platform are: a lens-free interferometric microscope (LIM) and a microfluidic cartridge with a functionalized plasmonic chip for the label-free detection of biomarkers. The LIM is also able to measure the phase modulation in commercial plasmonic chips. More specifically the thesis describes: • The development of a LIM with a large field of view and depth of field showing a sensitivity of 1nm along the beam propagation axis, which allows, for instance, the measurements of ultra-thin (2nm thickness) transparent silica and protein monolayer microarrays. • The generation of periodic structured light beams, obtained using a simple configuration including the birefringent elements of the LIM. These can be applied not only to imaging and biomarker detection but also in additive manufacturing and micro-structuring of surfaces. • The phase measurement of commercial surface plasmon resonance chips for the detection of changes in the refractive index of liquids. The phase measurements provide a sensitivity for bulk refractive index changes that is about one order of magnitude larger than for intensity-based detection under similar conditions. These results show a potential enhancement of the sensitivity of standard systems used in the biomedical community. • The development of a POC device comprising the LIM as a reader of specifically designed plasmonic gold nanohole array chips. The reading of the phase signal in the LIM shows a sensitivity increased by one order of magnitude thanks to the enhanced localized surface plasmon resonance interaction. Low concentrations of proteins and bacteria (as low as a single unit) are detected in measurements that also include human samples. This platform has the potential to multiplex the signal for simultaneous detection of thousands or even millions of different biomarkers. The LIM presented in this thesis is a very sensitive and robust imaging system with a high performance level for the detection of small quantities of transparent materials, with applications in microscopy and biomedicine.A medida que los sistemas de salud combaten epidemias y enfermedades infecciosas, nuevas formas de diagnóstico deben desarrollarse para satisfacer la creciente demanda de servicios, a menudo en lugares sin la infraestructura necesaria. Una solución emergente a este problema son los dispositivos de punto de atención (POC por sus siglas en inglés) ya que pueden proporcionar un diagnóstico rápido sin la necesidad de personal especializado o infraestructura compleja. En esta tesis mostramos el desarrollo de una plataforma POC para la detección rápida y temprana de infecciones, en particular Sepsis, una reacción inflamatoria de todo el cuerpo con altas tasas de mortalidad. Los principales componentes de esta plataforma son: un microscopio interferométrico sin lentes (LIM por sus siglas en inglés) y un cartucho de microfluídica con un chip plasmónico funcionalizado para la detección de biomarcadores, libre de marcadores adicionales. El LIM es también capaz de medir la modulación de fase en chips plasmónicos comerciales. Más específicamente, la tesis describe: * El desarrollo del LIM con un gran campo de visión y profundidad de campo mostrando una sensibilidad de 1nm a lo largo del eje de propagación del haz, que permite, por ejemplo, las mediciones de microarreglos ultrafinos (grosor de 2nm) y transparentes de Sílica y de monocapas de proteína.* La generación de haces de luz estructurados periódicos, obtenidos usando una configuración simple que incluye los elementos birrefringentes del LIM. Estos pueden ser aplicados no sólo a la detección de imágenes y biomarcadores, sino también a la fabricación aditiva y microestructuración de superficies. * La medición de fase en chips comerciales por resonancia de plasmón superficial para la detección de cambios en el índice de refracción de líquidos. Las mediciones de fase proporcionan una sensibilidad para cambios de índice de refracción en bulto que es aproximadamente un orden de magnitud mayor que para la detección basada en la intensidad con condiciones similares. Estos resultados muestran una potencial mejora de la sensibilidad de los sistemas estándar utilizados en la comunidad biomédica. * El desarrollo de un dispositivo POC que comprende el LIM como lector de chips plasmónicos de oro con arreglos de nano-agujeros específicamente diseñados. La lectura de la señal de fase en el LIM muestra un aumento de un orden de magnitud en la sensibilidad gracias a la interacción mejorada por la resonancia de plasmón superficial localizado. Bajas concentraciones de proteínas y bacterias (tan bajas como una sola bacteria) se detectan en mediciones que también incluyen muestras humanas. Esta plataforma tiene el potencial de multiplexar la señal para la detección simultánea de miles o incluso millones de biomarcadores diferentes. El LIM presentado en esta tesis es un sistema de imagen muy sensible y robusto con un alto nivel de rendimiento para la detección de pequeñas cantidades de materiales transparentes, con aplicaciones en microscopía y biomedicina.Postprint (published version

An investigation of frequency scanning interferometery for the alignment of the ATLAS semiconductor tracker

The relative alignment of the silicon detector modules of the ATLAS semiconductor tracker will need remote monitoring during operation, within a high radiation environment. A geodetic grid of distance measurement fibre-coupled interferometers will monitor changes in the shape of the support structure. Eight hundred fibre-coupled grid line interferometers (GLIs) will be compared simultaneously to a stable, evacuated reference interferometer using Frequency Scanning Interferometry (FSI). The GLIs, (from 70 mm to 1400mm long, with pW level return signals) must be measured to a precision of 1 micron, to reconstruct the grid shape, in three dimensions, to a precision of 10 microns. In this work two important limitations were overcome: 1. Inflated errors due to relative interferometer drift were significantly reduced using two lasers scanned in opposite directions. 2. The fine tuning range was effectively extended by linking the phase information in two 30 GHz fine tuning subscans, separated by a 3.5 THz coarse tuning interval. A demonstration system was built using tunable laser diodes operating at wavelengths close to 836 nm. Several different fibre coupled GLIs were built. Each was measured against an invar reference interferometer sharing the same laboratory air. The 400 mm GLI was measured to a (one standard deviation) precision of 120 nm and a 1195 nm GLI to a precision of 215 nm. Decreasing the GLI signal was not found to significantly degrade the measurement precision. Spurious reflections and vibrations were separately introduced to degrade the measurements. The errors were found to increase, with errors larger than 4 parts per million, observed for vibrations of 400 nm peak to peak amplitude. Suggestions are given for reducing remaining errors. Further investigations into the effects of vibrations and spurious reflections are recommended

Traceable onboard metrology for machine tools and large-scale systems

Esta tesis doctoral persigue la mejora de las funcionalidades de las máquinas herramienta para la fabricación de componentes de alto valor añadido. En concreto, la tesis se centra en mejorar la precisión de las máquinas herramienta en todo su volumen de trabajo y en desarrollar el conocimiento para realizar la medición por coordenadas trazable con este medio productivo. En realidad, la tecnología para realizar mediciones en máquina herramienta ya está disponible, como son los palpadores de contacto y los softwares de medición, sin embargo, hay varios factores que limitan la trazabilidad de la medición realizada en condiciones de taller, que no permiten emplear estas medidas para controlar el proceso de fabricación o validar la pieza en la propia máquina-herramienta, asegurando un proceso de fabricación de cero-defectos. Aquí, se propone el empleo del documento técnico ISO 15530-3 para piezas de tamaño medio. Para las piezas de gran tamaño se presenta una nueva metodología basada en la guía VDI 2617-11, que no está limitada por el empleo de una pieza patrón para caracterizar el error sistemático de la medición por coordenadas en la máquina-herramienta. De esta forma, se propone una calibración previa de la máquina-herramienta mediante una solución de multilateración integrada en máquina, que se traduce en la automatización del proceso de verificación y permite reducir el tiempo y la incertidumbre de medida. En paralelo, con el conocimiento generado en la integración de esta solución en la máquina-herramienta, se propone un nuevo procedimiento para la caracterización de la precisión de apunte del telescopio LSST en todo su rango de trabajo. Este nuevo procedimiento presenta una solución automática e integrada con tecnología láser tracker para aplicaciones de gran tamaño donde la precisión del sistema es un requerimiento clave para su buen funcionamiento.<br /

Mechatronic Design, Dynamics, Controls, and Metrology of a Long-Stroke Linear Nano-Positioner

Precision motion systems find a broad range of application in various fields such as micro/nano machining tools, lithography scanners, testing and metrology machines, micro-assembly, biotechnology, optics manufacturing, magnetic data-storage, and optical disk drives. In this thesis, an ultraprecision motion stage (nano-positioner) is designed and built based on the concept of a low-cost desktop precision micro machine tool. Linear positioning performance requirements of such a machine tool are used as design objectives. The nano-positioner’s mechatronic design is carried out in such a way to integrate different components towards high performance in terms of high dynamic range, high feedrate, servo accuracy, and geometric accuracy. A self-aligning air-bearing/bushing arrangement is employed for frictionless motion with infinite theoretical resolution, as well as reduced assembly costs and footprint. The air discharge from the air bearings/bushings are also utilized for assistance in the removal of heat dissipated from actuator coils. A voice coil actuator (VCA) is chosen for continuous, non-contact operation, and designed from scratch. A number of dimensional variables of the cylindrical VCA are set according to required forces, motion range, production/assembly tolerances, magnet availability, leakage flux, etc. The remainder of variables is determined according to two novel optimization objectives defined independent of the coil wire gauge, which separately aim for maximum stage acceleration capacity and minimum heat generation per generated force. The actuators are operated in a complementary double configuration for control simplicity which allows for a straightforward and robust design for controller stability. Controller design is carried out at current control and position control levels. Current frequency response of the voice coil actuators is obtained, and they are observed to possess additional high frequency dynamics on top of the expected first order lumped resistance and inductance model. These are attributed to the eddy currents in the stator structure. A closed loop bandwidth of better than 907 [Hz] is achieved using the integrator plus lead current controller. The position controller is designed using the identified overall plant which includes the moving body, current dynamics and the force response. The lead-lag position controller is tuned at 450 [Hz] cross-over frequency and 40 [deg] phase margin. The control error during the tracking of a step trajectory filtered at 40 [Hz] is found to vary between ±5 [nm], indicating a 4 million dynamic range over the 20 [mm] stroke length. Dynamic Error Budgeting (DEB) method has been used to resolve the components of the error, and the largest contributor is found to be the sensor noise. The actual positioning error, which is an ideal signal excluding sensor noise is estimated using the same methodology and disturbance models, and it is found to be 0.680 [nm] root-mean-square (RMS). For the trajectory following case, experiments are carried out with and without a compensation scheme for encoder quadrature detection errors. The compensation is observed to reduce the ±45 [nm] control error to ±15 [nm]. For the assessment of stage performance and the verification of design choices, modal testing and laser interferometric metrology have been applied to the linear nano-positioner. For modal testing, two independent methods are used and their predictions are compared. In the first method, a graphical approach, namely the peak-picking method, is employed to identify modal parameters (natural frequency and damping ratio) and mode shapes. In the second method, a modal testing software package is used to identify the same using automated algorithms. The first mode, which is the most critical one for controller design, is identified at 65 [Hz] as a roll mode, followed by horizontal, vertical, and pitch modes at 450, 484, and 960 [Hz], respectively. The geometric errors of the system are identified using laser interferometric measurements, using various optical setups for linear and angular components. An error budget is formed using these results, together with the estimated thermal errors and servo errors. The accuracy of the stage is determined to be ±5.0 [μm], which had a ±1.1 [μm] non-repeatable component. In the future, the controller structure can be enhanced with an additional pole beyond the crossover frequency, in order to suppress unnecessary oscillations of the control effort signal around the set point due to the encoder noise transmitted to the controller input. Using an estimation of air bearing pitch stiffness from the catalogue values for normal stiffness, the roll mode was predicted at 672 [Hz]. The much lower natural frequency for that mode identified in modal testing (65 [Hz]) can be attributed to the shortcomings of the estimation method, primarily the neglect of the distortion of the supporting air cushion at the bearing interface due to out of plane rotations. In the future, experimental data can be obtained to characterize the air bearing pitch stiffness more accurately. It was observed that the preferred compensation scheme for the encoder quadrature detection errors is unable to match third and fourth harmonics of the encoder measurement error sufficiently. In the future, better compensation methods can be investigated for an improved match. During laser interferometric measurements, measurement uncertainty due to laser beam misalignment and air turbulence were inferred to be high. In the future, better ways to align the laser with the optics, as well as methods for improved assessment and compensation of environmental effects can be investigated

Structured Beams as Quantum Probes

This thesis describes several projects under the common theme of generating and manipulating the spatial quantum phase structure of matter and electromagnetic waves. Experiments dealing with the following topics are addressed: perfect crystal neutron interferometry, far-field phase-grating moire interferometry, orbital angular momentum (OAM), spin-orbit states, and lattices of spin-orbit states. The first focus of the thesis is describing the work related to the construction of a new beamline dedicated to quantum information related neutron interferometry experiments at the National Institute of Standards and Technology's Center for Neutron Research. This includes the development of the necessary environmental isolation, phase stability, and temperature isolation mechanisms; and the installation and optimization of spin polarization elements. The new beamline is now operational and it is currently one of only three neutron interferometry facilities in the world. The second focus of the thesis is to describe the development and characterization of far-field phase-grating moire neutron interferometry. This technique enables studies that are complimentary to those of perfect crystal neutron interferometry experiments. It may be used to probe structured materials and characterize neutron interactions with potential gradients. A two phase-grating moire neutron interferometer was developed, characterized, and optimized. This setup was then employed to probe the microstructure of a monodisperse suspension of 2 um diameter polystyrene spheres. Furthermore, a three phase-grating moire neutron interferometer was developed and characterized. This unique setup promises a wide range of impactful experiments from far-field imaging of material substructure to fundamental physics. The third focus of the thesis is to describe neutron OAM. These experiments revolve around the preparation and characterization of an azimuthally varying phase profile. The demonstration of neutron OAM using a perfect crystal neutron interferometer is described, where a spiral phase plate was used to induce OAM in one of the paths of the interferometer. Furthermore, a modified setup was used to perform neutron holography of a macroscopic object which induces an azimuthally varying phase profile. These methods provide a new tool for interferometric testing of neutron optics and the characterization of coherence of neutron beams. The last focus of the thesis is to describe matter wave and optical spin correlated OAM (spin-orbit) states. Methods to prepare neutron spin-orbit states via special geometries of magnetic fields are proposed. The preparation, entanglement characterization, and proposed experimental verification of such states are described in detail. Furthermore, a method which is capable of preparing lattices of optical and neutron spin-orbit states is introduced and described. This method utilizes novel optical and neutron devices and it is based on coherent averaging and spatial control methods borrowed from nuclear magnetic resonance. The experimental preparation and characterization of optical lattices of spin-orbit states is described in detail