Manufacturing Process Controls for the Industries of the Future (1998) / Chapter Skim
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3 Research Opportunities
3 Research Opportunities
Pages 28-44
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From page 28... ...
The panel also reviewed technologies in the following areas: · emerging first-principle measurements · data validation and information extraction from multiple high-speed data streams · process operator interfacing, efficiency, and safety · control systems to improve process efficiency and reduce downtime PROCESS SENSORS The development of the next generation of sensor technologies is being driven by the common need of IOF industries to improve product quality, processing performance, and yield while optimizing energy efficiency and reducing the adverse environmental impact of manufacturing. The lack of advanced realtime process measurements and control systems is currently considered a critically limiting factor in the realization of these objectives as industries move into the next century.
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From page 29... ...
The realization of these next-generation technologies will require innovative sensors with new sensing techniques and transducer elements. As described in Chapter 2, the required measurements include · the measurement of temperature profiles in harsh processing environments · the measurement of chemical composition/stoichiometry in harsh processing environments · the measurement of physical attributes at high line speeds and high temperatures · the monitoring of combustion processes For the applications that require direct immersion-type sensors in harsh environments, materials (including materials for the entire sensor system, which consists of sensor elements, packaging, leads, interconnects, and actuators)
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From page 30... ...
Natural systems diagnostics are critical to monitoring the performance of processing equipment in conditionhased maintenance programs. The advantages and promise of natural system behavior diagnostics are listed below: · non-intrusive and remote process monitoring · no need for additional cables and field sensors at the process point · high sensitivity to a wide range of mechanical and electrical disorders · high selectivity among disorders of processes and machines General Research Opportunities in Sensor Technology Among the many research opportunities identified by the panel for creating the next generation of sensor technologies are · sensors and transducers capable of reliably measuring composition and temperature in harsh environmental conditions · low-cost, high-volume production of sensors · reliable, robust sensors · integrated sensors produced using integrated circuit processing approaches ("sensors on a chip")
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From page 31... ...
in the development of new probes include problems with drift, hysteresis, and electromagnetic interference. New high-speed, low-cost silicon digital signal processor devices, although not compatible with exposure to temperatures above approximately 250°C (NRC, 1995)
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In general, implementing chemical composition monitors in manufacturing will require continued research to develop innovative sensors; miniaturize sensors and ancillary equipment; develop engineered materials for chemical specificity and sensitivity (for new chemical probes) ; develop lower cost, more robust electro-optics; and incorporate chemometrics to improve the calibration, performance, and reliability of new and existing analyzers.
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From page 33... ...
Current state-of-the-art processing methods have not addressed the formidable challenge of developing the materials and processing strategies for a sensor that gives a specific response to a chemical perturbation. Critical areas for research in integrated sensors and MEMS devices are assembly, interfacing, and packaging.
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From page 34... ...
The prospect of being able to deploy new sensors rapidly anywhere in a manufacturing plant without the costs of cabling, connections, and associated labor presents a significant opportunity for using advanced wireless sensors in the future. Research would have to address the needs and overcome the barriers listed below: · eliminate interference from metal structures in the manufacturing envi ronment · use intelligent, integrated sensors · develop reliable wireless networks for process monitoring and control · develop remote power systems for wireless devices · standardize communication protocols, interfaces, and software Analysis and Visualization of Process Measurements Even without the expected increase in the use of sensors for process monitoring and control, manufacturers face the daunting prospect of dealng with databases of unprecedented size and complexity.
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From page 35... ...
include · methodologies to enable in-situ-level process control · plantwide or enterprise-level optimization · hybrid process models · tools for open-architecture applications · adaptive control systems Process Control Methodologies The principal objective for the process industries represented by the IOF is to develop technology to enable the transition of controls from the environmental level to the in-situ level (described in Chapter 2~. Areas where process control technology can be significantly improved include · effective use of process measurements · robust on-line learning (intelligence applications)
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· Chaos theory is already being applied to industrial processes, such as power generation, to extract ordered models of global behavior from apparently random signals (Garrison, 19971. Recently, advances have been made in several technologies relevant to process controls.
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is a key area for research (Samad, 19971. Many different types of process models are now used in the materials process industries, including models based on first principles, empirical knowledge, heuristic knowledge, steadystate behavior, dynamic behavior, linear behavior, and nonlinear behavior.
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Plantwide optimization has proved to be very beneficial to the petrochemical industries. Applicability of these optimization systems to the other IOF industries will depend on the availability of accurate hybrid models for both large-batch processes and continuous processes and compatibility with existing controllers.
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From page 39... ...
Entry 1 c ~ l RESEARCH OPPORTUNITIES 39 High Loop Heating Holding Retard speed Loop assembly chamber chamber cooler cooler assembly Specific research should be focused on the areas listed below: · automated data analysis to identify key process variables that affect profitability, energy consumption, and waste generation · integration of process controls with maintenance operations and monitoring of equipment health (see Box 3-2) · approaches to optimization that increase profitability while minimizing energy consumption and environmental impact
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Source: Dudzic, 1997. · large-scale, nonlinear optimization algorithms (a refinery model, for example, may consist of more than one million nonlinear equations)
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Many characteristics of industrial processes (time constants, stable dynamics, and operational understanding) are compatible with adaptation, and industries have been waiting for practical adaptive control technologies for decades.
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~2 ~_ ~~ co~3 FACES Dudz1c, ad.
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From page 43... ...
Presentation to the Panel on Manufacturing Process Controls, National Research Council, Washington, D.C., May 29, 1997. NRC (National Research Council)
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1997. Finishing Mill Electric Machine Expert Advisor for Production Optimization.
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