scholarly journals Implementation of Virtual Sensors for Monitoring Temperature in Greenhouses Using CFD and Control

Sensors ◽  
2018 ◽  
Vol 19 (1) ◽  
pp. 60 ◽  
Author(s):  
Cesar Guzmán ◽  
José Carrera ◽  
Héctor Durán ◽  
Javier Berumen ◽  
Arturo Ortiz ◽  
...  
Keyword(s):  
Real Time ◽  
Convection Heat Transfer ◽  
Small Scale ◽  
Measuring Instruments ◽  
Cfd Analysis ◽  
Virtual Sensor ◽  
Virtual Sensors ◽  
Model Based ◽  
Virtual Sensing ◽  
And Control

Virtual sensing is crucial in order to provide feasible and economical alternatives when physical measuring instruments are not available. Developing model-based virtual sensors to calculate real-time information at each targeted location is a complex endeavor in terms of sensing technology. This paper proposes a new approach for model-based virtual sensor development using computational fluid dynamics (CFD) and control. Its main objective is to develop a three-dimensional (3D) real-time simulator using virtual sensors to monitor the temperature in a greenhouse. To conduct this study, a small-scale greenhouse was designed, modeled, and fabricated. The controller was based on the convection heat transfer equation under specific assumptions and conditions. To determine the temperature distribution in the greenhouse, a CFD analysis was conducted. Only one well-calibrated and controlled physical sensor (temperature reference) was enough for the CFD analysis. After processing the result that was obtained from the real sensor output, each virtual sensor had learned the associative transfer function that estimated the output from given input data, resulting in a 3D real-time simulator. This study has demonstrated, for the first time, that CFD analysis and a control strategy can be combined to obtain system models for monitoring the temperature in greenhouses. These findings suggest that, generally, virtual sensing can be applied in large greenhouses for monitoring the temperature using a 3D real-time simulator.

Neural Network Based Control of Preform Permeation in Resin Transfer Molding Processes With Real-Time Permeability Estimation

2000 ◽  
Author(s):  
David Nielsen ◽  
Ranga Pitchumani
Keyword(s):  
Neural Network ◽  
Real Time ◽  
Resin Transfer Molding ◽  
Local Pressure ◽  
Transfer Molding ◽  
Model Based ◽  
Rtm Process ◽  
Virtual Sensing ◽  
Intelligent Model ◽  
Injection Pressures

Abstract Variabilities in the preform structure in situ in the mold are an acknowledged challenge to effective permeation control in the Resin Transfer Molding (RTM) process. An intelligent model-based controller is developed which utilizes real-time virtual sensing of the permeability to derive optimal decisions on controlling the injection pressures at the mold inlet ports so as to track a desired flowfront progression during resin permeation. This model-based optimal controller employs a neural network-based predictor that models the flowfront progression, and a simulated annealing-based optimizer that optimizes the injection pressures used during actual control. Preform permeability is virtually sensed in real-time, based on the flowfront velocities and local pressure gradient estimations along the flowfront. Results are presented which illustrate the ability of the controller in accurately steering the flowfront for various fill scenarios and preform geometries.

scholarly journals A Real-Time Dynamic Fuel Cell System Simulation for Model-Based Diagnostics and Control: Validation on Real Driving Data

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3148 ◽  
Author(s):  
Daniel Ritzberger ◽  
Christoph Hametner ◽  
Stefan Jakubek
Keyword(s):  
Fuel Cell ◽  
Real Time ◽  
Combustion Engine ◽  
System Simulation ◽  
Measurement Data ◽  
Fuel Cell Vehicle ◽  
Feedback Controls ◽  
Model Based ◽  
And Control ◽  
Stack Model

Fuel cell systems are regarded as a promising candidate in replacing the internal combustion engine as a renewable and emission free alternative in automotive applications. However, the operation of a fuel cell stack fulfilling transient power-demands poses significant challenges. Efficiency is to be maximized while adhering to critical constraints, avoiding adverse operational conditions (fuel starvation, membrane flooding or drying, etc.) and mitigating degradation as to increase the life-time of the stack. Owing to this complexity, advanced model-based diagnostic and control methods are increasingly investigated. In this work, a real time stack model is presented and its experimental parameterization is discussed. Furthermore, the stack model is integrated in a system simulation, where the compressor dynamics, the feedback controls for the hydrogen injection and back-pressure valve actuation, and the purging strategy are considered. The resulting system simulation, driven by the set-point values of the operating strategy is evaluated and validated on experimental data obtained from a fuel cell vehicle during on-road operation. It will be shown how the internal states of the fuel cell simulation evolve during the transient operation of the fuel cell vehicle. The measurement data, for which this analysis is conducted, stem from a fuel cell research and demonstrator vehicle, developed by a consortium of several academic and industrial partners under the lead of AVL List GmbH.

scholarly journals Monitoring Dynamic Structural Tests Using Image Deblurring Techniques

2013 ◽  
Vol 569-570 ◽  
pp. 932-939 ◽  
Author(s):  
David M.J. McCarthy ◽  
Jim H. Chandler ◽  
Alessandro Palmeri
Keyword(s):  
Image Processing ◽  
Real Time ◽  
High Speed ◽  
Image Resolution ◽  
Test Element ◽  
Small Scale ◽  
Measuring Instruments ◽  
Imaging Results ◽  
Blurred Image ◽  
Structural Tests

Photogrammetric techniques have demonstrated their suitability for monitoring static structural tests. Advantages include scalability, reduced cost, and three dimensional monitoring of very high numbers of points without direct contact with the test element. Commercial measuring instruments now exist which use this approach. Dynamic testing is becoming a convenient approach for long-term structural health monitoring. If image based methods could be applied to the dynamic case, then the above advantages could prove beneficial. Past work has been successful where the vibration has either large amplitude or low frequency, as even specialist imaging sensors are limited by an inherent compromise between image resolution and imaging frequency. Judgement in sensor selection is therefore critical. Monitoring of structures in real-time is possible only at a reduced resolution, and although imaging and computer processing hardware continuously improves, so the accuracy demands of researchers and engineers increase. A new approach to measuring vibration is introduced here, whereby a long-exposure photograph is used to capture a blurred image of the vibrating structure. The high resolution blurred image showing the whole vibration interval is measured with no need for high-speed imaging. Results are presented for a series of small-scale laboratory models, as well as a larger scale test, which demonstrate the flexibility of the proposed technique. Different image processing strategies are presented and compared, as well as the effects of exposure, aperture and sensitivity selection. Image processing time appears much faster, increasing suitability for real-time monitoring.

Author response for "Model-based design and control of a small-scale integrated continuous end-to-end mAb platform"

2020 ◽  
Author(s):  
Joaquín Gomis-Fons ◽  
Hubert Schwarz ◽  
Liang Zhang ◽  
Niklas Andersson ◽  
Bernt Nilsson ◽  
...  
Keyword(s):  
Author Response ◽  
Small Scale ◽  
Model Based ◽  
End To End ◽  
And Control

The Design and Implementation of G-RBAC Model in Map Permission

2011 ◽  
Vol 268-270 ◽  
pp. 1457-1461
Author(s):  
Ji Qiu Deng ◽  
Xiao Qing Luo ◽  
Huang Ling Gu
Keyword(s):  
Access Control ◽  
Real Time ◽  
Spatial Data ◽  
Role Based Access Control ◽  
Design And Implementation ◽  
Model Based ◽  
Valid Method ◽  
Role Based ◽  
And Control

With the development of WebGIS, it plays a more and more important role in government and enterprises. The effective way to access and control spatial data, because of relating to the security and business secrets of government and enterprises, becomes an urgent concern for them. Now, RBAC (Role Based Access Control) can be a valid method to access and control uniform resource, but it is lack of flexibility and real-time ability to control spatial data in WebGIS. For that, this paper proposes G-RBAC model based on RBAC model to enhance the flexibility and real-time ability to access spatial data.

Implementation of Simulation-Based Virtual Sensors Using Radiance and Java

2016 ◽  
Vol 824 ◽  
pp. 740-747 ◽  
Author(s):  
Vaibhav Jain ◽  
Ardeshir Mahdavi
Keyword(s):  
Boundary Conditions ◽  
Real Time ◽  
Sensor Data ◽  
Internal Boundary ◽  
Virtual Sensor ◽  
Virtual Sensors ◽  
Capital Costs ◽  
Automation Systems ◽  
Building Operation ◽  
Operation Phase

Building performance simulation is traditionally used to support the building design process. However, it can also be used during building operation phase by providing relevant data to building automation systems. We refer to monitoring and metering data generated by computational simulation (virtual) models as data from virtual sensors. Virtual sensors, if reliably and effectively incorporated, can expand the reach of real sensors. A continuous supply of virtual sensor data can support near real-time representation of both primary environmental variables (e.g., air temperature, relative humidity) as well as complex performance indicators (e.g., thermal comfort indices, visual glare). Such information, especially in large multi-zone buildings, would be otherwise expensive to obtain from real sensors due to high capital costs of the sensors, their installation, networking, and maintenance. Virtual sensors can increase the resolution of sensory information, as they imply little monetary expenditures and are not limited in view of numbers and location.Conventional building energy simulation uses a model of the building and creates boundary conditions using historic weather data and predefined schedules for lighting and equipment load. This method is suitable for evaluation of building designs but not suitable for monitoring and control processes during building operation phase, as such processes usually require actual real-time information regarding boundary conditions. Thus, capability to automatically update simulation model's boundary conditions in real-time using monitored data is required. Toward this end, a supervisory software application is developed, in Java programming language, to implement and illustrate the concept of virtual sensors using Radiance simulation program. This application creates virtual illuminance sensors in Radiance model and then automates the process of regularly updating simulation model's external and internal boundary conditions (solar irradiance, state of electrical lighting elements) by using real-time monitored data from on-site weather station and building management system (BMS). As a result, the simulation kernel can continuously generate virtual sensor readings that can be utilized by building monitoring and/or control systems. This paper discusses the general architecture of the application, to further illustrate the concept of virtual sensors. Moreover, it discusses the accuracy of virtual illuminance sensors by comparing their output with monitored illuminance data in realistic test scenarios.

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