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Computer-Controlled Systems
Published in Jitendra R. Raol, Ramakalyan Ayyagari, Control Systems, 2020
Jitendra R. Raol, Ramakalyan Ayyagari
In past decades, there has been a paradigm shift in methodology of measurements/sensing, interpretation of data/signals, and implementation of control systems/strategies, mainly due to continuous technological innovations supported by fast and accurate digital technology and components, such as analog-to-digital converters (ADC), transducers, microprocessors/microcontrollers and, hence, integrated digital computer technology, all resulting into computer (-based) control and measurement systems [16]. Also, this has been supported by the associated advancements in communication technology that has replaced natural scale-up procedures of manual monitoring and control by highly advanced automated systems. Today, computers and the associated software (SW) have become very powerful in terms of speed, throughput, and memory, and the application of computer-controlled system is justified automatically because of its low cost, its capabilities to handle large, complex industrial processes, and it use in many aerospace control applications. The computers: (a) ensure the repeatability/precision and accuracy of the controlled processes, (b) permit flexibility to modify the sequencing and control procedures, and (c) provide increased understanding of the behavior of the processes.
Fiber-Optic Sensors
Published in Banshi Dhar Gupta, Anand Mohan Shrivastav, Sruthi Prasood Usha, Optical Sensors for Biomedical Diagnostics and Environmental Monitoring, 2017
Banshi Dhar Gupta, Anand Mohan Shrivastav, Sruthi Prasood Usha
The parameter reproducibility is defined as the changeability in the median value when the same experiment is repeated by different operators. It qualifies and quantifies a system by checking the experimental measurements repeated over a long period of time. Reproducibility thus incorporates repeatability. The percentage of reproducibility is evaluated in simple terms by taking the ratio of the obtained result and expected result, multiplied by 100. Stability parameter of sensor is interrelated with the repeatability and reproducibility assessment factors. For example, by measuring the absorbance of a particular analyte concentration by keeping the sensor in the analyte vicinity continuously shows the stability behavior of the sensor system. By performing the stability experiments multiple times, the repeatability and reproducibility parameters of the sensor can also be evaluated.
Introduction
Published in S.T. Smith, D.G. Chetwynd, Foundations of Ultraprecision Mechanism Design, 2017
Repeatability Repeatability is a measure of the scatter of results obtained if an attempt is made to exactly repeat a given operation. There is no uniquely agreed measure, but commonly either the standard deviation or the half-width of the distribution of the results might be used. Unless one is prepared to truncate values to a numeric precision much smaller than the system capability, repeated measurements are doomed to produce varied results because errors are always present and are fickle by their very nature. The repeatability of a system is not related to its linearity except when non-linearities are large enough to cause a multi-valued (non-monotonic) characteristic. Poor mechanical repeatability is commonly associated with hysteresis due to backlash or is simply inherent to the transducer as, for example, with piezoelectric gauges. With careful design, the repeatibility may approach, but can never be better than, the resolution.
Design and validation of a gripper for the automated assembly of film components in flexible electronics manufacturing
Published in International Journal of Computer Integrated Manufacturing, 2023
Marcello Valori, Vito Basile, Gianmauro Fontana, Jose A. Mulet Alberola, Serena Ruggeri, Simone Pio Negri, Irene Fassi
The total execution time of film coverlay manual assembly can widely variate as a function of the coverlay films, i.e. dimensions and shape/profile, and the FPCB complexity. Roughly, each coverlay assembly requires a total execution time in the range of 50 ÷ 120 s. Each circuit can have up to four coverlays for each circuit and each panel can have up to 100 circuits, therefore operators are requested to assemble hundreds of coverlays for each processed panel. In addition, some operations, such as protective film removal and coverlay positioning, are demanding, alienating and tiring (i.e. causing eye fatigue and non-ergonomic postures). Finally, yet importantly, the manual assembly can introduce positioning errors that can affect the product waste rate. Automating the task will result in a relief of the operators from the stressful tasks related to the detachment of the protective film and accurate positioning of the coverlay. Process timing can be decreased in the measure of one order of magnitude, with consequent increase in assembled components, improving the overall process throughput. Once automated, the overall process repeatability can be significantly improved.
Laboratory load-based testing and performance rating of residential heat pumps in heating mode
Published in Science and Technology for the Built Environment, 2023
Parveen Dhillon, Li Cheng, W. Travis Horton, James E. Braun
There is also ongoing research to evaluate the repeatability, reproducibility, and representativeness of load-based testing that is extremely important in assessing its potential for use in future standards. Repeatability refers to the consistency in a test unit’s measured performance when the test procedure is applied multiple times in the same lab, whereas reproducibility refers to the consistency in a test unit’s measured performance across different test facilities. Assessing repeatability and reproducibility involves the application of round-robin tests across different laboratories for multiple heat pumps. Representativeness involves understanding how well the virtual building model mimics building behavior and its interaction with the equipment. Evaluating representativeness requires field testing for different building types and using that data to validate emulated behavior in the laboratory for the same equipment. Finally, there is a need to perform comprehensive comparisons of seasonal performance ratings determined using load-based and steady-state testing approaches to better understand the advantages and disadvantages of each. Data obtained in repeatability, reproducibility, and representativeness studies could be employed for this purpose.
Study of the Explosion Suppression Mechanism of Different Separate and Explosion-Proof Materials
Published in Combustion Science and Technology, 2022
Jiancun Gao, Xigang Yang, Shoutao Hu, Le Wang, Zijin Hong, Ruxia Li, Xu Sun
These materials were processed into a uniform cylindrical and dense filling based on the shape of the pipe. Additionally, 5% crevice rate (the ratio of space to container volume of unfilled separate and explosion-proof materials) was left at the ignition head end of the pipeline for effective ignition. The device was made airtight, followed by replacing the air in the pipe with synthetic air (79% N2, 21% O2). A vacuum pump was then used to achieve negative pressure. This was followed by filling with 57 mL C3H8 (5% volume fraction), and the synthetic air was replenished with the pipe to atmospheric pressure. The gas in the pipe was homogenized evenly. An ignition system was used to detonate the gas. The experiments were carried out in accordance with industry standards and replicated to ensure repeatability. Pressure data were measured with a pressure data collector. After the gas explosion, the sampling system was used to collect the gas explosion products. Explosion product collection device is shown in Figure 2.