Manufacturing Metrology

Metrology is the science of measurement, which can be divided into three overlapping activities: (1) the definition of units of measurement, (2) the realization of units of measurement, and (3) the traceability of measurement units. Manufacturing metrology originally implicates the measurement of components and inputs for a manufacturing process to assure they are within specification requirements. It can also be extended to indicate the performance measurement of manufacturing equipment. This Special Issue covers papers revealing novel measurement methodologies and instrumentations for manufacturing metrology from the conventional industry to the frontier of the advanced hi-tech industry. Twenty-five papers are included in this Special Issue. These published papers can be categorized into four main groups, as follows: Length measurement: covering new designs, from micro/nanogap measurement with laser triangulation sensors and laser interferometers to very-long-distance, newly developed mode-locked femtosecond lasers. Surface profile and form measurements: covering technologies with new confocal sensors and imagine sensors: in situ and on-machine measurements. Angle measurements: these include a new 2D precision level design, a review of angle measurement with mode-locked femtosecond lasers, and multi-axis machine tool squareness measurement. Other laboratory systems: these include a water cooling temperature control system and a computer-aided inspection framework for CMM performance evaluation

An electromagnetic imaging system for metallic object detection and classification

PhD ThesisElectromagnetic imaging currently plays a vital role in various disciplines, from engineering to medical applications and is based upon the characteristics of electromagnetic fields and their interaction with the properties of materials. The detection and characterisation of metallic objects which pose a threat to safety is of great interest in relation to public and homeland security worldwide. Inspections are conducted under the prerequisite that is divested of all metallic objects. These inspection conditions are problematic in terms of the disruption of the movement of people and produce a soft target for terrorist attack. Thus, there is a need for a new generation of detection systems and information technologies which can provide an enhanced characterisation and discrimination capabilities. This thesis proposes an automatic metallic object detection and classification system. Two related topics have been addressed: to design and implement a new metallic object detection system; and to develop an appropriate signal processing algorithm to classify the targeted signatures. The new detection system uses an array of sensors in conjunction with pulsed excitation. The contributions of this research can be summarised as follows: (1) investigating the possibility of using magneto-resistance sensors for metallic object detection; (2) evaluating the proposed system by generating a database consisting of 12 real handguns with more than 20 objects used in daily life; (3) extracted features from the system outcomes using four feature categories referring to the objects’ shape, material composition, time-frequency signal analysis and transient pulse response; and (4) applying two classification methods to classify the objects into threats and non-threats, giving a successful classification rate of more than 92% using the feature combination and classification framework of the new system. The study concludes that novel magnetic field imaging system and their signal outputs can be used to detect, identify and classify metallic objects. In comparison with conventional induction-based walk-through metal detectors, the magneto-resistance sensor array-based system shows great potential for object identification and discrimination. This novel system design and signal processing achievement may be able to produce significant improvements in automatic threat object detection and classification applications.Iraqi Cultural Attaché, Londo

High-accuracy Motion Estimation for MEMS Devices with Capacitive Sensors

With the development of micro-electro-mechanical system (MEMS) technologies, emerging MEMS applications such as in-situ MEMS IMU calibration, medical imaging via endomicroscopy, and feedback control for nano-positioning and laser scanning impose needs for especially accurate measurements of motion using on-chip sensors. Due to their advantages of simple fabrication and integration within system level architectures, capacitive sensors are a primary choice for motion tracking in those applications. However, challenges arise as often the capacitive sensing scheme in those applications is unconventional due to the nature of the application and/or the design and fabrication restrictions imposed, and MEMS sensors are traditionally susceptible to accuracy errors, as from nonlinear sensor behavior, gain and bias drift, feedthrough disturbances, etc. Those challenges prevent traditional sensing and estimation techniques from fulfilling the accuracy requirements of the candidate applications. The goal of this dissertation is to provide a framework for such MEMS devices to achieve high-accuracy motion estimation, and specifically to focus on innovative sensing and estimation techniques that leverage unconventional capacitive sensing schemes to improve estimation accuracy. Several research studies with this specific aim have been conducted, and the methodologies, results and findings are presented in the context of three applications. The general procedure of the study includes proposing and devising the capacitive sensing scheme, deriving a sensor model based on first principles of capacitor configuration and sensing circuit, analyzing the sensor’s characteristics in simulation with tuning of key parameters, conducting experimental investigations by constructing testbeds and identifying actuation and sensing models, formulating estimation schemes is to include identified actuation dynamics and sensor models, and validating the estimation schemes and evaluating their performance against ground truth measurements. The studies show that the proposed techniques are valid and effective, as the estimation schemes adopted either fulfill the requirements imposed or improve the overall estimation performance. Highlighted results presented in this dissertation include a scale factor calibration accuracy of 286 ppm for a MEMS gyroscope (Chapter 3), an improvement of 15.1% of angular displacement estimation accuracy by adopting a threshold sensing technique for a scanning micro-mirror (Chapter 4), and a phase shift prediction error of 0.39 degree for a electrostatic micro-scanner using shared electrodes for actuation and sensing (Chapter 5).PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/147568/1/davidsky_1.pd

Synthetic Aperture Radar (SAR) data processing

The available and optimal methods for generating SAR imagery for NASA applications were identified. The SAR image quality and data processing requirements associated with these applications were studied. Mathematical operations and algorithms required to process sensor data into SAR imagery were defined. The architecture of SAR image formation processors was discussed, and technology necessary to implement the SAR data processors used in both general purpose and dedicated imaging systems was addressed

Low cost radar and sonar using Open Source hardware and software

Includes abstract.Includes bibliographical references (leaves 89-91).The full range of radar types and innovations can be complex and difficult to prototype, especially for institutions that wish to perform a wide range of experiments for low financial cost. Radar and sonar system development can benefit from digital technology that is powerful for research purposes, easy to use, and inexpensive. The purpose of this thesis was the development of a sonar application using the Universal Software Radio Peripheral and the GNU Radio software framework. These are Open Source tools created for the software-defined radio community. These tools provide a powerful yet flexible means to experiment with a wide range of radio frequency applications, using a minimal amount of relatively cheap hardware. In this thesis, these tools were modified from their original telecommunications purpose, to produce a sonar system that could eventually be scaled to a prototype radar system using the same device and software framework

Radar Technology

In this book “Radar Technology”, the chapters are divided into four main topic areas: Topic area 1: “Radar Systems” consists of chapters which treat whole radar systems, environment and target functional chain. Topic area 2: “Radar Applications” shows various applications of radar systems, including meteorological radars, ground penetrating radars and glaciology. Topic area 3: “Radar Functional Chain and Signal Processing” describes several aspects of the radar signal processing. From parameter extraction, target detection over tracking and classification technologies. Topic area 4: “Radar Subsystems and Components” consists of design technology of radar subsystem components like antenna design or waveform design

Advanced control of ultrashort and high-power pulses in enhancement cavities

In the decade preceding this thesis, femtosecond enhancement cavities had emerged as a highly promising technology in the context of extreme ultraviolet light (XUV) sources for frequency comb metrology and attosecond physics. These applications require light of laser-like coherence, which can be provided by high-order harmonic generation (HHG), a highly nonlinear frequency conversion process driven by intense ultrashort laser pulses. The laser systems commonly used to drive HHG are limited to pulse repetition rates in the kilohertz range. In contrast, the enhancement of femtosecond pulses in passive optical cavities to average powers of many kilowatts delivers the necessary intensities even at repetition rates of tens to hundreds of megahertz. Achieving sufficient XUV flux with megahertz repetition rates would enable the extension of frequency comb metrology to the XUV, and dramatically reduce data acquisition times for experiments in attosecond physics. However, cavity-enhanced HHG comes with unique challenges, imposing cavity-related limitations to the power, peak intensity, and minimum duration of the driving pulses. In this thesis, several novel approaches to extending the capabilities of femtosecond enhancement cavities are presented. In a first experiment, we demonstrated the compensation of thermal lensing effects in enhancement cavities. Using intracavity Brewster plates, which also offer a robust solution for XUV output coupling in cavity-enhanced HHG setups, we gained control over the thermally-induced mode change at average powers of up to 160 kW. Subsequently, we investigated the effects of nonlinear phase modulations caused by ionization in an intracavity gas target, which is a prerequisite for HHG. We experimentally validated a numerical model of the plasma-cavity interaction, leading to a scaling law allowing for the layout of optimized cavity HHG systems, and a proposal for tailoring the spectral finesse of cavities to exploit the nonlinear phase modulation for intracavity pulse compression. In parallel, we worked on the design and characterization of highly reflective multilayer mirrors to optimize the cavity dispersion. Combining different mirrors with compatible spectral phase characteristics, we demonstrated enhancement cavities supporting waveform-stable pulses, and cavities supporting pulse durations approaching the few-cycle regime. These results represent vital technological developments towards the goal of isolated attosecond pulse generation with enhancement cavities. Finally, we applied the developed methods of dispersion control to design an enhancement cavity for intracavity pulse compression using self-phase modulation in a Brewster plate. Implementing a flexible locking scheme, we demonstrated for the first time the generation of temporal cavity solitons in free-space enhancement cavities. The temporal compression from 350 fs to 37 fs together with the spectrally tailored finesse resulted in a peak power enhancement factor of over 3000, significantly surpassing the enhancement in linear cavities supporting similar pulse durations. This intriguing result opens the door to a novel regime of nonlinear cavity operation, with potentially significant benefits to cavity-enhanced HHG. In addition, we proposed a concept for optomechanical cavity dumping, with the potential to aid efforts employing enhancement cavities for a new generation of high-pulse-energy lasers

The Deep Space Network. An instrument for radio navigation of deep space probes

The Deep Space Network (DSN) network configurations used to generate the navigation observables and the basic process of deep space spacecraft navigation, from data generation through flight path determination and correction are described. Special emphasis is placed on the DSN Systems which generate the navigation data: the DSN Tracking and VLBI Systems. In addition, auxiliary navigational support functions are described