Evaluation of selected strapdown inertial instruments and pulse torque loops, volume 1

Design, operational and performance variations between ternary, binary and forced-binary pulse torque loops are presented. A fill-in binary loop which combines the constant power advantage of binary with the low sampling error of ternary is also discussed. The effects of different output-axis supports on the performance of a single-degree-of-freedom, floated gyroscope under a strapdown environment are illustrated. Three types of output-axis supports are discussed: pivot-dithered jewel, ball bearing and electromagnetic. A test evaluation on a Kearfott 2544 single-degree-of-freedom, strapdown gyroscope operating with a pulse torque loop, under constant rates and angular oscillatory inputs is described and the results presented. Contributions of the gyroscope's torque generator and the torque-to-balance electronics on scale factor variation with rate are illustrated for a SDF 18 IRIG Mod-B strapdown gyroscope operating with various pulse rebalance loops. Also discussed are methods of reducing this scale factor variation with rate by adjusting the tuning network which shunts the torque coil. A simplified analysis illustrating the principles of operation of the Teledyne two-degree-of-freedom, elastically-supported, tuned gyroscope and the results of a static and constant rate test evaluation of that instrument are presented

Stress Injection Study on Hard Real-Time Operating Systems

The automotive software complexity has increased exponentially in the last 30 years. Nowadays, automotive applications are built on top of hard real-time operating system where many tasks are executed. Due to the automotive high integration levels and the time-to-market, software integration and robustness tests should be performed effectively and efficiently. Infineon Technologies for the AURIX 2G microcontroller has integrated a novel hardware architecture to support the Resource Usage Test and the Stress Test. Despite this hardware support, it has never been used before. Then, it is critical to propose a method to efficiently use this structure and to allow the evaluation of the performance and reliability of the chips. This thesis develops a method and a tool that uses stress injection to analyze the performance, robustness values and boundaries of hard real-time systems under different scenarios. The designer is able: i) to configure the embedded debugging hardware architecture to efficiently explore different stress scenarios; ii) to gather information; and to quantify different types of performance and robustness metrics. The method is automated and fully parameterizable. The developed tool in this thesis is called Galenus, it is integrated into the already existing internal debugging environment of Infineon Technologies for the AURIX microcontroller. The stress injection is based on the reduction of the effective performance of a SoC component (e.g., TriCore within AURIX). The stress injection allows to assess the sensitivity of the SoC under different stress scenarios. These scenarios are defined on the offline initial state using formal methods of scheduling theory. Using the stress injection method, the SoC designer can identify possible risk scenarios testing the performance and robustness of the system at runtime. This thesis is based on the stress injection by CPU suspension within two types of software application, RTOS and Bare-metal

Principles for designing an effective, post-compulsory music curriculum suitable for Western Australia

A new post-compulsory Music course known as the Western Australian Certificate of Education (WACE) Music course was recently introduced into Year 11 and 12 in Western Australian (WA) schools. Following a convoluted process of creation, its implementation into classrooms has been problematic. Given criticism levelled at its process of creation and implementation, the researcher questions whether the WACE Music course embodies effective, recognised principles to support the effective teaching and learning of music. This study investigates the principles which should form the basis of an effective, post-compulsory music curriculum, suitable for WA. It involved a literature review which sought to produce a set of principles for teaching and learning frameworks based upon international best practice in music education, and applicable in the unique geographical, historical and multicultural WA context. In addition, the study employed a researcher–designed survey instrument to examine whether Western Australian music teachers perceived these principles to be evident in their practical experiences of the new WACE music course. With the subsequent publishing of a draft Australian National Arts Curriculum, it is an appropriate time to review the principles which should underpin an effective Music curriculum for senior secondary students in the WA context because, without a clear set of guiding principles that are understood by curriculum writers, there is a possibility that following courses could be fundamentally flawed and not serve the best interests of students

Comparison between transfer path analysis methods on an electric vehicle

A comparison between transfer path analysis and operational path analysis methods using an electric vehicle is presented in this study. Structure-borne noise paths to the cabin from different engine and suspension points have been considered. To realise these methods, two types of test have been performed; operational tests on a rolling road and hammer tests in static conditions. The main aim of this work is assessing the critical paths which are transmitting the structure-borne vibrations from the electric vehicle?s vibration sources to the driver?s ear. This assessment includes the analysis of the noise contribution of each path depending on the frequency and vehicle speed range and moreover, the assessment of the path noise impact for harmonic orders which arise due to the physical components of the electric vehicle. Furthermore, the applicability of these methods to electric vehicles is assessed as these techniques have been extensively used for vehicles powered with internal combustion engines.The authors would like to acknowledge the COST ACTION TU1105 for supporting this research

Comparison between transfer path analysis methods on an electric vehicle

A comparison between transfer path analysis and operational path analysis methods using an electric vehicle is presented in this study. Structure-borne noise paths to the cabin from different engine and suspension points have been considered. To realise these methods, two types of test have been performed; operational tests on a rolling road and hammer tests in static conditions. The main aim of this work is assessing the critical paths which are transmitting the structure-borne vibrations from the electric vehicle's vibration sources to the driver's ear. This assessment includes the analysis of the noise contribution of each path depending on the frequency and vehicle speed range and moreover, the assessment of the path noise impact for harmonic orders which arise due to the physical components of the electric vehicle. Furthermore, the applicability of these methods to electric vehicles is assessed as these techniques have been extensively used for vehicles powered with internal combustion engines

Spaceborne Gravity Gradiometers

The current status of gravity gradiometers and technology that could be available in the 1990's for the GRAVSAT-B mission are assessed. Problems associated with sensors, testing, spacecraft, and data processing are explored as well as critical steps, schedule, and cost factors in the development plan

Implementation of an active seismic isolation system for the AEI 10 m prototype

The first direct observation of gravitational waves on the 14th September 2015 opened up a new window to the Universe. Since then, gravitational wave astronomy has provided highly valuable information about previously mostly unexplored astronomic events like the merger of two black holes; nevertheless, it is still in its infancy, with numerous phenomena to be discovered and investigated. This requires improved detectors, featuring higher sensitivities. Seismic noise is among the most relevant noise sources for current gravitational wave detectors. Although featuring sophisticated seismic isolation systems, current detectors are directly and indirectly limited by seismic noise below 30 Hz; therefore, current and future detectors require novel isolation systems and strategies to achieve their design sensitivity. The Albert Einstein Institute (AEI) 10m prototype is a test facility for gravitational wave detectors to develop and study novel technology. The primary goal is to reach and surpass the interferometric Standard Quantum Limit (SQL) based on quantum noise. It requires significant suppression of all classical noise contributions in order to achieve the design sensitivity. AEI Seismic Attenuation Systems (AEI-SASs) isolate the sub-SQL interferometer against seismic noise and are used to develop and demonstrate novel techniques for gravitational wave detectors. The AEI-SASs combine passive isolation based on the principle of a harmonic oscillator and active isolation based on feedback loop suppression. In the scope of this thesis, the active seismic isolation of the AEI-SASs is implemented and analyzed in detail. Two different isolation strategies are described, namely local seismic isolation and global seismic isolation. The former is predominantly used by current gravitational wave detectors and focuses on inertial isolation of each interferometer component individually. The latter is a mostly untested principle implemented in the AEI 10m prototype in a unique realization. It focuses on the minimization of differential motion between the interferometer components. All involved sensors are characterized, and their noise is calculated. The sensor noise is measured in so-called huddle tests with excellent agreement to the models, providing detailed insight into limitations of the sensors and the entire system. Requirements for precise huddle tests are investigated in measurements. The application of local isolation techniques at the AEI 10m prototype is described and novel methods for their improvement are demonstrated. An enhanced coordinate system transformation increases the decoupling between different degrees of freedom, resulting in better isolation performance. The sensitivity dependence on the sensor alignment is analyzed in a novel approach, enabling the capability of a sensitivity optimization and an improved system characterization. The combination of different sensors to exploit their most sensitive frequency regimes is optimized using a new calculation method. It is adapted for the purpose of global isolation by including inter-platform sensors and the coupling of motion of the globally isolated AEI-SASs to the sub-SQL interferometer. This method simultaneously provides detailed information about limitations of the isolation system, which is used to propose and analyze possible improvements for the global isolation. An optimization of digital filters is calculated to improve the seismic isolation by a factor of 1.4. A realistic upgrade of vertical sensors offers an additional improvement of up to a factor of 4.3. Some fundamental statements of global isolation are confirmed by measurements. Furthermore, a noise budget of the AEI sub-SQL interferometer is simulated. Requirements on noise suppression and interferometric parameters are set by comparison to the SQL. Based on these requirements, a possible design for the anti-symmetric port photodetector is motivated, and its noise is analyzed

Many suspensions, many problems: a review of self-suspending tasks in real-time systems

In general computing systems, a job (process/task) may suspend itself whilst it is waiting for some activity to complete, e.g., an accelerator to return data. In real-time systems, such self-suspension can cause substantial performance/schedulability degradation. This observation, first made in 1988, has led to the investigation of the impact of self-suspension on timing predictability, and many relevant results have been published since. Unfortunately, as it has recently come to light, a number of the existing results are flawed. To provide a correct platform on which future research can be built, this paper reviews the state of the art in the design and analysis of scheduling algorithms and schedulability tests for self-suspending tasks in real-time systems. We provide (1) a systematic description of how self-suspending tasks can be handled in both soft and hard real-time systems; (2) an explanation of the existing misconceptions and their potential remedies; (3) an assessment of the influence of such flawed analyses on partitioned multiprocessor fixed-priority scheduling when tasks synchronize access to shared resources; and (4) a discussion of the computational complexity of analyses for different self-suspension task models