Modeling and Optimal Semi Active Control Strategies for adaptive MRTMD

2013 ◽  
Author(s):  
Alessia Ussia ◽  
Alessio Bonelli ◽  
Oreste S. Bursi
Keyword(s):  
Active Control ◽  
Control Strategies

scholarly journals Active Control of Greenhouse Climate Enhances Papaya Growth and Yield at an Affordable Cost

Agronomy ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 378
Author(s):  
Irene Salinas ◽  
Juan José Hueso ◽  
Julián Cuevas
Keyword(s):  
Active Control ◽  
Skin Color ◽  
Natural Ventilation ◽  
Control Strategies ◽  
Soluble Solids ◽  
Growth And Yield ◽  
Climate Control ◽  
Tropical Fruit ◽  
Greenhouse Climate ◽  
Solids Content

Papaya is a tropical fruit crop that in subtropical regions depends on protected cultivation to fulfill its climate requirements and remain productive. The aim of this work was to compare the profitability of different climate control strategies in greenhouses located in subtropical areas of southeast Spain. To do so, we compared papayas growing in a greenhouse equipped with active climate control (ACC), achieved by cooling and heating systems, versus plants growing in another greenhouse equipped with passive climate control (PCC), consisting of only natural ventilation through zenithal and lateral windows. The results showed that ACC favored papaya plant growth; flowering; fruit set; and, consequently, yields, producing more and heavier fruits at an affordable cost. Climate control strategies did not significantly improve fruit quality, specifically fruit skin color, acidity, and total soluble solids content. In conclusion, in the current context of prices, an active control of temperature and humidity inside the greenhouse could be a more profitable strategy in subtropical regions where open-air cultivation is not feasible.

The Use of Damping Based Semi-Active Control Algorithms in the Mechanical Smart-Spring System

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Wander Gustavo Rocha Vieira ◽  
Fred Nitzsche ◽  
Carlos De Marqui
Keyword(s):  
Active Control ◽  
Control Algorithm ◽  
Control Strategies ◽  
Vibration Reduction ◽  
Flow Analysis ◽  
Coupled Systems ◽  
Control Technique ◽  
Control Algorithms ◽  
Control Techniques ◽  
Spring Mechanism

In recent decades, semi-active control strategies have been investigated for vibration reduction. In general, these techniques provide enhanced control performance when compared to traditional passive techniques and lower energy consumption if compared to active control techniques. In semi-active concepts, vibration attenuation is achieved by modulating inertial, stiffness, or damping properties of a dynamic system. The smart spring is a mechanical device originally employed for the effective modulation of its stiffness through the use of semi-active control strategies. This device has been successfully tested to damp aeroelastic oscillations of fixed and rotary wings. In this paper, the modeling of the smart spring mechanism is presented and two semi-active control algorithms are employed to promote vibration reduction through enhanced damping effects. The first control technique is the smart-spring resetting (SSR), which resembles resetting control techniques developed for vibration reduction of civil structures as well as the piezoelectric synchronized switch damping on short (SSDS) technique. The second control algorithm is referred to as the smart-spring inversion (SSI), which presents some similarities with the synchronized switch damping (SSD) on inductor technique previously presented in the literature of electromechanically coupled systems. The effects of the SSR and SSI control algorithms on the free and forced responses of the smart-spring are investigated in time and frequency domains. An energy flow analysis is also presented in order to explain the enhanced damping behavior when the SSI control algorithm is employed.

Comparative research on semi-active control strategies for magneto-rheological suspension

2009 ◽  
Vol 59 (3) ◽  
pp. 433-453 ◽  
Author(s):  
Xiao-min Dong ◽  
Miao Yu ◽  
Chang-rong Liao ◽  
Wei-min Chen
Keyword(s):  
Active Control ◽  
Comparative Research ◽  
Control Strategies ◽  
Magneto Rheological

Active Control of Elastodynamic Vibrations of a Flexible Mechanism With Piezoelectric Actuator

1999 ◽  
Author(s):  
Ching-I Chen
Keyword(s):  
Control Theory ◽  
Active Control ◽  
Piezoelectric Actuator ◽  
Control Strategies ◽  
Piezoelectric Actuators ◽  
Structural Vibration ◽  
Control Technique ◽  
Vibration Modes ◽  
Time Sharing ◽  
Transient Dynamic

Abstract This study focused on the application of active vibration control strategies for flexible moving structures which degrade into transient dynamic vibration problem. These control strategies are based primarily on modal control methods in which the flexible moving structures are controlled by reducing their dominant vibration modes. This work numerically investigated active control of the elastodynamic response of a four-bar mechanical system, using a piezoelectric actuator. A controller based on the modified independent modal space control theory was also utilized. This control theory produced overall excellent performance in terms of achieving the desired closed-loop structural damping. The merits of this technique include its ability to manage the spill-over effect, i.e. eliminate the magnitude of vibrations associated with uncontrolled modes, using only a few selected modes for control. This control was accomplished using a time sharing technique, which reduces the number of piezoelectric actuators required to control a large number of vibration modes. Furthermore, this algorithm implements a procedure for determining the optimal locations for the piezoelectric actuators. The dynamics of a steel four-bar linkage was selected with a flexible coupler separated by six elements and one piezoelectric actuator was used in the numerical simulation. The optimal actuator position was located at the third element from the right to the left. Results in this study demonstrated that a highly desired the structural vibration damping could be achieved. This control technique can be applied to transient dynamic systems.

scholarly journals Testing and isolation strategies for the vibrational hazards

2019 ◽  
Vol 39 (2) ◽  
pp. 124-131
Author(s):  
Huang Wei ◽  
Xu Jian ◽  
Zhang Tong-yi ◽  
Hu Ming-yi ◽  
Qin Jing-wei ◽  
...  
Keyword(s):  
Active Control ◽  
Control Strategies ◽  
Green Building ◽  
Power Equipment ◽  
Civil Structures ◽  
Severe Problem ◽  
Ground Floor ◽  
Initial Design ◽  
The Future ◽  
Water Pumps

In this paper, a test for investigating the vibrational hazards occurred in a modernized hospital was carried out, in which a lot of power equipment such as chilled water pumps and freezers, etc. were installed in the ground floor. The generated vibrations could be experienced on the upper floors including some medical precision room. Next, solation and active control strategies were proposed, and evidently the active control could improve the suppression a lot. This study illustrated that the great vibrational hazards could not be ignored anymore, and the followed resolution strategies for eliminating these vibrations seemed to be urgent. In tradition, the vibration isolations would not be involved in initial design for civil structures, but in fact this might lead to a severe problem to be addressed in the future, and this study could give inspiration for green building.

Validation and Implementation of Control Strategies for Liquid Composite Molding Processes

Materials ◽  
2003 ◽  
Author(s):  
Mathieu Devillard ◽  
Kuang-Ting Hsiao ◽  
Suresh G. Advani
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Control Strategies ◽  
Process Models ◽  
Injection System ◽  
Composite Part ◽  
Rtm Process ◽  
Flow Disturbances ◽  
Filling Time ◽  
Optimization Search

The manufacturing of polymeric composites ranges from using a rudimentary hand lay-up to the use of automated processes such as Liquid Composite Modeling (LCM) developed over the past decades in order to increase the yield of manufactured composite parts. In these processes, fiber preforms are placed in a closed mold and resin is infused into the mold to saturate the preform. After the resin cures, the mold is opened and the net shape composite part is demolded. However, by introducing more complexity into the part, one also introduces higher probability of flow disturbances, such as race tracking along preform edges, into the molding system. This can lead to incomplete saturation of fiber performs resulting in flaws such as dry spots in the composite part. The strength and existence of race-tracking is a function of the fabric type, perform manufacturing method, and its placement in the mold. It can vary from one part to the next in the same production run, and therefore it is not repeatable. In this work, after illustrating experimentally the unpredictability of variation of race-tracking and its influence on the flow, two approaches have been investigated and validated to address this issue associated with the variation of inherent disturbances in LCM processes. An active control strategy method using process models and simulations along with sensing and control to address flow disturbances during the impregnation stage of the process was shown to be reliable and effective for Resin Transfer Molding (RTM) process. In an attempt to improve the automation of RTM process, a modular RTM workstation including all hardware and software necessary to implement active control strategies for various part geometries and a novel injection system was designed and tested. In addition, a passive control method for Vaccum Assisted RTM (VARTM) aimed at optimizing the placement of distribution media for a given set-up in order to reduce dry spot formation and filling time was developed and validated experimentally. The optimization method employs numerical flow simulations and global optimization search techniques (Genetic algorithm) to generate the design for strategic flow control system.

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