This paper deals with the problem of technological process control systems modernization in Lietuvos Elektrine AB. There was analyzed a structure of existing steam boilers. There are presented requirements for steam b...
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SCADA systems use many modern programming technologies. The amount of knowledge needed to use them steadily grows. In the paper is presented the application, which shows the user how to solve many industry problems us...
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Model Predictive Control (MPC) is an advanced control strategy for improving the control of processes that display relatively large variations in system controlled output values in comparison to the system's contr...
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Model Predictive Control (MPC) is an advanced control strategy for improving the control of processes that display relatively large variations in system controlled output values in comparison to the system's control set point, for processes with appreciable process variable interactions, and for systems that display a large amount of process deadtime and/or system disturbances This paper reports the implementation of MPC techniques directly on a programmablelogic controller (PLC) rather than on a personal computer (PC) for an industrial sugar cooking process. This study implemented and evaluated three PC-based, commercial MPC technologies for the sugar cooking process, and a new model state feedback implementation directly on Rockwell Automation's ControlLogix® PLC. A standard proportional-integral-derivative (PID) control implementation was used as a baseline for comparing the MPC strategies. The comparative analysis focused on the dynamic response of each strategy at startup, including both temperature rise time and overshoot, and the steady-state disturbance rejection capabilities of each strategy. The test results showed that the MPC strategies controlled the sugar cooking process better than the traditional PID control method in regards to the target parameters. The tests also showed that the PLC-based MPC strategy was comparable to the PC-based commercial MPC applications. This strategy has several benefits such as requiring no external hardware, software, and communications protocols, which may result in a less expensive implementation than the commercial MPC strategies. This is of particular interest for implementation in an educational setting due to the lower cost, use of standard laboratory equipment, and relevance to Electrical Engineering and Engineering Technology curriculum.
This paper presents a new prototyping technique, which allows efficient verification of circuit concepts based on negative differential resistance (NDR) devices. This prototype, which is called MOS-NDR, has been used ...
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This paper presents a new prototyping technique, which allows efficient verification of circuit concepts based on negative differential resistance (NDR) devices. This prototype, which is called MOS-NDR, has been used to implement programmablelogic gates and pipelined-ripple-carry full adders using linear threshold gates (LTGs).
Today there is a standard for the implementation of programs on programmable logic controllers (PLCs). Furthermore there are methods for the formal development of these programs. The standard allows the interchange of...
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Partial Valve Stroke Testing or PVST, is an emerging concept to automatically increase the performance of Safety Instrumented Systems. PVST is a concept where safety-related valves like ESD valves and shut-off valves ...
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Partial Valve Stroke Testing or PVST, is an emerging concept to automatically increase the performance of Safety Instrumented Systems. PVST is a concept where safety-related valves like ESD valves and shut-off valves are automatically tested concerning failure modes that are related to valve sticking and slowing down operation. Current trends in the industry show an upcoming number of dedicated technical PVST solutions by various automation and instrumentation vendors. The added value of PVST within the process industries is a significant reduction of the frequency of required manual periodic valve proof tests, its related manual test cost and reduced spurious trips due to manual errors. Partial testing is performed by additional automated test instrumentation, which can easily be initiated and controlled by the safety-instrumented systems' logic solver such as the safety-related PLC. This paper will discuss practical examples of Partial Valve Stroke Testing in which it appears that SIL 1 rated valves can be upgraded to SIL 2, and off-line proof test intervals which can be extended from 2 to 5 years. Copyright 2004 by ISA - The Instrumentation, Systems and Automation Society.
In many practical applications PLC engineers face the problem, that some essential hardware the PLC is supposed to operate, is not available during software development and commissioning, yet. Because of missing feedb...
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As SoC design enters into mainstream usage, the ability to make post-fabrication changes will become more and more attractive. This ability can be realized using programmablelogic cores. These cores are like any othe...
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Previous work has suggested that "soft" synthesizable programmablelogic cores can efficiently provide small amounts of post-fabrication flexibility to integrated circuits. Previous architectures restrict th...
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Operational problems with robot manipulators in space relate to several factors, one most importantly being structural flexibility and subsequently significant difficulties with the control systems, especially, for po...
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ISBN:
(纸本)1563476703
Operational problems with robot manipulators in space relate to several factors, one most importantly being structural flexibility and subsequently significant difficulties with the control systems, especially, for position control. This paper presents a comparison of fuzzy logic system (FLS) controllers to determine an optimal design for tracking the endpoint of a two-link flexible robot. The dominant assumed mode of vibration for an Euler-Bernoulli cantilever beam is coupled with the nonlinear dynamics for rigid links to form an Euler-Lagrange inverse flexible dynamics robot model. A Jacobian transpose control law is adapted by a FLS with link deformation inputs and a single variable output. Simulation results for three, five, seven and nine triangular and Gaussian membership functions are compared to identify an optimal design for best tracking control and least computation time. Results show the optimal choice of FLS is three triangular membership functions at 14 min 51 sec tracking time.
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