Selection of parameters of optoelectronic systems for monitoring the wear for steam turbine rotor blading based on the value of the total error

Optoelectronic wear monitoring system of rotor blades of steam turbine low-pressure cylinders provide an assessment of the chord value of the working blade in static conditions on a closed cylinder. However, these systems do not allow the operator to assess the wear with the necessary error during shaft rotation. The control process is complicated by the fact that the output edge of the blade is overlapped by the input edge of the next blade; therefore it is necessary to set a scanning direction for each section that will ensure the formation of blade video frames, including both the input and output edges. The shaft rotation mode requires the use of pulsed illumination of the edges of the working blades to reduce the amount of image smudge; therefore it is necessary to select the focal length of the camera lens, the diameter of the entrance pupil of the lens and the power of pulsed radiation sources. The development of a methodology for selecting system parameters will help to reduce the complexity of designing systems for various turbine models and application technologies. Therefore, this is an important task. A methodology has been developed for selecting the parameters of the wear control systems of the working blades, which is based on the criterion of equality of the main components of the total error of the chord value. The analytical studies used the relationship of the parameters of the matrix receiver of optical radiation, illumination sources and the optical circuit with the required characteristics of the system. Computer modeling of the information conversion process in the system under study took into account the relationship between the parameters of the moving blades and the parameters of the optical circuit. The experimental estimation of the system error in statics and dynamics is based on multiple measurements after calibration of the system according to known parameters of the blades. When using the developed methodology, it is possible to achieve the required field of view and a given error in controlling the chord value, due to the choice of: matrix optical radiation receiver, focal length of the camera lens, diameter of the lens entrance pupil, and power of radiation sources. Using the example of the fifth stage of the vane device of the K-1200 high unit power turbine, which is most susceptible to wear, it is shown that for maximum values of the rotation angles of the video probe is 19° and the delay time of frame synchronization is up to 0.18 s, the focal length of the camera lens should be less than 2.4 mm with a pulse illumination time of 0.05 s. Computer modeling has shown that the marginal error of the system can reach 0.011 mm, which illustrates the possibility of reducing the total error. Using the developed methodology, the main elements were selected and a layout of the system was created. The requirements for exposure time and delay time of frame synchronization are formulated. The effectiveness of the parameter selection methodology was confirmed by experimental studies of the system layout, which showed that the estimate of the standard deviation of the random component of the chord control error in dynamics was 0.26 mm, which is three times less than that of the previously developed system and meets the requirements for evaluating the operability of the rotor blades of steam turbines during operation and repair. The proposed technique can be used by developers of other optoelectronic means of contactless control of linear dimensions of parts oriented non-perpendicular to the line of sight

Design and Performance of a 1 ms High-Speed Vision Chip with 3D-Stacked 140 GOPS Column-Parallel PEs †

We have developed a high-speed vision chip using 3D stacking technology to address the increasing demand for high-speed vision chips in diverse applications. The chip comprises a 1/3.2-inch, 1.27 Mpixel, 500 fps (0.31 Mpixel, 1000 fps, 2 × 2 binning) vision chip with 3D-stacked column-parallel Analog-to-Digital Converters (ADCs) and 140 Giga Operation per Second (GOPS) programmable Single Instruction Multiple Data (SIMD) column-parallel PEs for new sensing applications. The 3D-stacked structure and column parallel processing architecture achieve high sensitivity, high resolution, and high-accuracy object positioning

Stagioni: Temperature management to enable near-sensor processing for performance, fidelity, and energy-efficiency of vision and imaging workloads

abstract: Vision processing on traditional architectures is inefficient due to energy-expensive off-chip data movements. Many researchers advocate pushing processing close to the sensor to substantially reduce data movements. However, continuous near-sensor processing raises the sensor temperature, impairing the fidelity of imaging/vision tasks. The work characterizes the thermal implications of using 3D stacked image sensors with near-sensor vision processing units. The characterization reveals that near-sensor processing reduces system power but degrades image quality. For reasonable image fidelity, the sensor temperature needs to stay below a threshold, situationally determined by application needs. Fortunately, the characterization also identifies opportunities -- unique to the needs of near-sensor processing -- to regulate temperature based on dynamic visual task requirements and rapidly increase capture quality on demand. Based on the characterization, the work proposes and investigate two thermal management strategies -- stop-capture-go and seasonal migration -- for imaging-aware thermal management. The work present parameters that govern the policy decisions and explore the trade-offs between system power and policy overhead. The work's evaluation shows that the novel dynamic thermal management strategies can unlock the energy-efficiency potential of near-sensor processing with minimal performance impact, without compromising image fidelity.Dissertation/ThesisMasters Thesis Computer Engineering 201