A New Approach to Adaptive Control of Multi-Input Multi-Output Systems Using Multiple Models

2015 ◽  
Vol 137 (9) ◽  
Author(s):  
Narjes Ahmadian ◽  
Alireza Khosravi ◽  
Pouria Sarhadi
Keyword(s):  
Mimo Systems ◽  
Control Process ◽  
Operating Conditions ◽  
Multiple Models ◽  
Uncertain Environments ◽  
New Approach ◽  
Adaptive Laws ◽  
Novel Method ◽  
Model Bank ◽  
And Control

This paper proposes a novel method as second level adaptation using multiple models to identify and control of a class of multi-input multi-output (MIMO) systems. Different uncertain environments change the system parameters and create multiple operating conditions. These conditions are designed as multiple identification models in a model bank using adaptive laws. These models are evaluated using some estimated weighting factors based on the errors between each of the models and the actual plant. The evaluated models are effectively used in identification and control process. Bounded signals, proper closed-loop tracking performance, and rapid and accurate parameter convergence to their real values are achieved through simulation results.

Synchronizing Field and Control-Room Operators for Process Operating Transients

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Flavio Manenti ◽  
Davide Manca
Keyword(s):  
Systems Engineering ◽  
Dynamic Models ◽  
Control Process ◽  
Operating Conditions ◽  
Control Room ◽  
Process Systems ◽  
Plant Safety ◽  
Steady State Simulation ◽  
And Control ◽  
Start Ups

Process systems engineering is rapidly moving from steady state simulation towards operator training simulation, based on dynamic models, automated procedures, and predictive systems. Conventional operating conditions are well-known and easily controlled by field operators as well as control-room operators, whereas other situations are not yet. This is the case of more unusual circumstances, such as plant start-ups as well as planned and emergency shutdowns.The implementation of detailed dynamic mathematical models allows simulating the behavior of single process units as well as industrial plants, with the possibility to study unusual scenarios, especially for two reasons. First of all, it is necessary to train the operator and prepare him/her to face several events. Secondly, there is the need for evaluating the best automatic procedure to manage either unconventional or critical situations, without waiting for them to occur. In this sense, the safety approach is changing from reacting to predicting, thanks to the spread of tools that offer the possibility to simulate accidental events, unit and/or valve malfunctions, and significant process transients.The paper investigates and compares different procedures to control process transients, described by a sequence of actions, in order to coordinate synergistically the actions dictated by control-room operators and the operations to be accomplished manually by field operators. The main objective is to improve process start-up and shutdown reliability as well as the corresponding plant safety of an existing plant-wide control structure, without requiring any structural modification. A propane/butane splitter is adopted as a case study.

scholarly journals Experimental Research of Electromagnetic Field Influence on Digital Temperature Sensors with Single-Wire Lines to Study Possibility of Their Use in NPP Control Systems

2019 ◽  
pp. 14-18
Author(s):  
Yu. Bykovsky ◽  
V. Levchenko ◽  
O. Pogosov
Keyword(s):  
Electromagnetic Field ◽  
Temperature Sensors ◽  
Operating Conditions ◽  
Temperature Fields ◽  
Auxiliary Equipment ◽  
New Approach ◽  
Metrological Control ◽  
Control Technologies ◽  
Technical Interest ◽  
And Control

Issues related to the introduction of new control technologies and temperature monitoring at NPPs are being considered, since NPP longterm operation depends on the reliability of process control means. It is promising to build instrumentation and control complexes using one-wire technologies, since the operation information removal and transmission means should be carried out under the conditions of spatial constraints on the location of cabling. One-wire technologies make it easy to build a measurement network of the most complex topology. It is proposed to use DS18B20 universal digital primary measuring transducers as NPP testing equipment. In this regard, scientific and technical interest is a new approach to the measurement of temperature fields based on 1-Wire technology. It was proposed to use UR-1 demagnetizer as a source of a variable electromagnetic field imitating NPP equipment operating conditions. The paper also presents a study for visualization of the generated electromagnetic fields. A Hall sensor is used for measuring the fields under consideration. The proposed method can be used to conduct other similar studies to assess the response of temperature sensors (or other digital sensors) to an external magnetic field. A visualization method is used to evaluate the informational function and a conclusion is made about the applicability of such sensors in the systems of metrological control and monitoring of NPP auxiliary equipment.

scholarly journals Entropy-Based Risk Control of Geological Disasters in Mountain Tunnels Under Uncertain Environments

2018 ◽  
Author(s):  
Yuanpu Xia ◽  
Ziming Xiong ◽  
Hao Lu ◽  
Xin Dong
Keyword(s):  
Decision Making ◽  
Risk Control ◽  
Engineering Application ◽  
Control Process ◽  
Uncertain Environments ◽  
Underground Engineering ◽  
Entropy Model ◽  
Key Factor ◽  
And Control ◽  
The Impact

Uncertainty is the main source of risk of geological hazards in tunnel engineering. Uncertainty information not only affects the accuracy of evaluation results, but also affects the reliability of decision-making schemes. Therefore, it is necessary to evaluate and control the impact of uncertainty on risk. In this study, the problems in existing entropy-hazard model such as inefficient decision-making and failure of decision-making are analysed, and an improved uncertainty evaluation and control process are proposed. Then the tolerance cost, the key factor in the decision-making model, is also discussed. It is considered that the amount of change in risk value (R1) can better reflect the psychological behaviour of decision-makers. Thirdly, common attribute decision models, such as the expected utility-entropy model, are analysed, and then the viewpoint of different types of decision-making issues that require different decision methods is proposed. The well-known Allais paradox is explained by the proposed methods. Finally, the engineering application results show that the uncertainty control idea proposed here is accurate and effective. This research indicates a direction for further research into uncertainty, and risk control, issues affecting underground engineering works.

scholarly journals Fault Detection and Control of Process Systems

2007 ◽  
Vol 2007 ◽  
pp. 1-20 ◽  
Author(s):  
Vu Trieu Minh ◽  
Nitin Afzulpurkar ◽  
W. M. Wan Muhamad
Keyword(s):  
Control System ◽  
Fault Detection ◽  
Predictive Control ◽  
Detection System ◽  
Control Process ◽  
Multiple Models ◽  
Interacting Multiple Model ◽  
Multiple Model ◽  
Process Systems ◽  
And Control

This paper develops a stochastic hybrid model-based control system that can determine online the optimal control actions, detect faults quickly in the control process, and reconfigure the controller accordingly using interacting multiple-model (IMM) estimator and generalized predictive control (GPC) algorithm. A fault detection and control system consists of two main parts: the first is the fault detector and the second is the controller reconfiguration. This work deals with three main challenging issues: design of fault model set, estimation of stochastic hybrid multiple models, and stochastic model predictive control of hybrid multiple models. For the first issue, we propose a simple scheme for designing faults for discrete and continuous random variables. For the second issue, we consider and select a fast and reliable fault detection system applied to the stochastic hybrid system. Finally, we develop a stochastic GPC algorithm for hybrid multiple-models controller reconfiguration with soft switching signals based on weighted probabilities. Simulations for the proposed system are illustrated and analyzed.

On-Surface Radical Oligomerisation: A New Approach to STM Tip-Induced Reactions

2018 ◽  
Author(s):  
Gaolei Zhan ◽  
Younes Makoudi ◽  
Judicael Jeannoutot ◽  
Simon Lamare ◽  
Michel Féron ◽  
...  
Keyword(s):  
Sample Surface ◽  
Scanning Tunnelling Microscope ◽  
Transfer Event ◽  
New Approach ◽  
The Past ◽  
Organic Nanostructures ◽  
Scanning Tunnelling ◽  
New Strategy ◽  
Surface Fabrication ◽  
And Control

Over the past decade, on-surface fabrication of organic nanostructures has been widely investigated for the development of molecular electronic devices, nanomachines, and new materials. Here, we introduce a new strategy to obtain alkyl oligomers in a controlled manner using on-surface radical oligomerisations that are triggered by the electrons/holes between the sample surface and the tip of a scanning tunnelling microscope. The resulting radical-mediated mechanism is substantiated by a detailed theoretical study. This electron transfer event only occurs when <i>V</i><sub>s</sub> < -3 V or <i>V</i><sub>s</sub> > + 3 V and allows access to reactive radical species under exceptionally mild conditions. This transfer can effectively ‘switch on’ a sequence leading to formation of oligomers of defined size distribution due to the on-surface confinement of reactive species. Our approach enables new ways to initiate and control radical oligomerisations with tunnelling electrons, leading to molecularly precise nanofabrication.

scholarly journals LiDAR-Based Glass Detection for Improved Occupancy Grid Mapping

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2263
Author(s):  
Haileleol Tibebu ◽  
Jamie Roche ◽  
Varuna De Silva ◽  
Ahmet Kondoz
Keyword(s):  
Laser Scanner ◽  
Point Clouds ◽  
Light Detection And Ranging ◽  
Test Results ◽  
New Approach ◽  
Occupancy Grid ◽  
Laser Scanners ◽  
Novel Method ◽  
Occupancy Grid Mapping ◽  
Cartesian Coordinate

Creating an accurate awareness of the environment using laser scanners is a major challenge in robotics and auto industries. LiDAR (light detection and ranging) is a powerful laser scanner that provides a detailed map of the environment. However, efficient and accurate mapping of the environment is yet to be obtained, as most modern environments contain glass, which is invisible to LiDAR. In this paper, a method to effectively detect and localise glass using LiDAR sensors is proposed. This new approach is based on the variation of range measurements between neighbouring point clouds, using a two-step filter. The first filter examines the change in the standard deviation of neighbouring clouds. The second filter uses a change in distance and intensity between neighbouring pules to refine the results from the first filter and estimate the glass profile width before updating the cartesian coordinate and range measurement by the instrument. Test results demonstrate the detection and localisation of glass and the elimination of errors caused by glass in occupancy grid maps. This novel method detects frameless glass from a long range and does not depend on intensity peak with an accuracy of 96.2%.

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