Fuzzy Multivariable Control Strategy Applied to a Refrigeration System

2016 ◽  
Vol 12 (2) ◽  
Author(s):  
Saulo Fernando dos Santos Vidal ◽  
Jones Erni Schmitz ◽  
Ivan Carlos Franco ◽  
Ana Maria Frattini Fileti ◽  
Flavio Vasconcelos Da Silva
Keyword(s):  
Energy Consumption ◽  
Fuzzy Controller ◽  
Fine Tuning ◽  
Refrigeration System ◽  
Process Variables ◽  
Pump Frequency ◽  
Comparative Performance ◽  
Control Effort ◽  
Squared Error ◽  
And Control

Abstract The refrigeration process involves complex systems exhibiting nonlinearities and coupled behavior, so this paper aims to evaluate the comparative performance of a multivariable fuzzy logic-based control system and a classic multi loop PID. The process variables were the temperature of the secondary fluid (propylene glycol) outlet and the evaporating temperature. The manipulated variables were the compressor frequency speed and the pump frequency speed. Aspen Plus and Aspen Dynamics simulators were used to simulate the experimental prototype. The model was previously validated and linked with MATLAB software, where the controllers were implemented. Tuning of the fuzzy controller was performed through the membership functions and gains adjustments. The tuning of the multi loop PID controller was performed using the Ziegler-Nichols method and then a fine tuning was carried out. In order to fairly compare energy consumption and control effort, the tune of PID-based strategy was finished when similar values of Integral of Squared Error were achieved. Thus, very similar behavior for the process variables in both controllers. On the other hand, a great improvement in the control effort and energy saving was observed when the multivariable fuzzy controller was used in comparison to classic PID. The energy consumption was reduced by 25 % and the control effort by 96 % when the proposed strategy was used.

scholarly journals Identification and Control of Impressed Current Cathodic Protection System

2016 ◽  
Vol 12 (2) ◽  
pp. 214-220 ◽  
Author(s):  
Bassim Sada ◽  
Ramzy Ali ◽  
Khearia Ali
Keyword(s):  
Cathodic Protection ◽  
Pid Controller ◽  
Fuzzy Controller ◽  
Fine Tuning ◽  
Control Technique ◽  
Temperature Conductivity ◽  
Impressed Current ◽  
And Control ◽  
Impressed Current Cathodic Protection ◽  
Identification Model

In this paper the identification and control for the impressed current cathodic protection (ICCP) system are present. Firstly, an identification model using an Adaptive Neuro-Fuzzy Inference Systems (ANFIS) was implemented. The identification model consists of four inputs which are the aeration flow rates, the temperature, conductivity, and protection current, and one output that represented by the structure-to-electrolyte potential. The used data taken from an experimental CP system model, type impressed current submerged sample pipe carbon steel. Secondly, two control techniques are used. The first control technique use a conventional Proportional-Integral-Derivative (PID) controller, while the second is the fuzzy controller. The PID controller can be applied to control ICCP system and quite easy to implement. But, it required very fine tuning of its parameters based on the desired value. Furthermore, it needed time response more than fuzzy controller to track reference voltage. So the fuzzy controller has a faster and better response.

Adaptive Hybrid Intelligent Tracking Control for Uncertain Fractional Order Chaotic Systems

2012 ◽  
Vol 1 (1) ◽  
pp. 1-16 ◽  
Author(s):  
Tsung-Chih Lin ◽  
Chia-Hao Kuo
Keyword(s):  
Fractional Order ◽  
Chaotic Systems ◽  
Fuzzy Controller ◽  
Tracking Error ◽  
Adaptive Fuzzy Control ◽  
Weighting Factor ◽  
Control Effort ◽  
Plant Knowledge ◽  
Control Knowledge ◽  
And Control

This paper presents an adaptive hybrid fuzzy controller to achieve prescribed tracking performance of fractional order chaotic systems. Depending on plant knowledge and control knowledge, a weighting factor can be adjusted by combining the indirect adaptive fuzzy control effort and the direct fuzzy adaptive control effort. Nonlinear fractional order chaotic response system is fully demonstrated to track the trajectory generated from fractional order chaotic drive system. The numerical results show that tracking error and control effort can be made smaller and the proposed hybrid intelligent control scheme is more flexible during the design process.

DIRECT ADAPTIVE TYPE-2 FUZZY CONTROL FOR NONLINEAR SYSTEMS

2006 ◽  
Vol 06 (03) ◽  
pp. 389-411 ◽  
Author(s):  
KHEIREDDINE CHAFAA ◽  
LAMIR SAIDI ◽  
MOUNA GHANAI ◽  
KHIER BENMAHAMMED
Keyword(s):  
Fuzzy Controller ◽  
Tracking Error ◽  
Nonlinear Dynamical System ◽  
Reference Trajectory ◽  
Oscillation System ◽  
Control Effort ◽  
Nonlinear Dynamical ◽  
Supervisory Controller ◽  
And Control

A new direct adaptive type-2 fuzzy controller for a nonlinear dynamical system is developed in this paper. The parameters of the membership functions characterizing the linguistic terms in the type-2 fuzzy IF–THEN rules change according to some adaptive law for the purpose of controlling a plant to track a reference trajectory. A supervisory controller is appended to the type-2 fuzzy controller to force the state to be within the constraint set. Stability of this adaptive scheme is established using Lyapunov stability tools, where we guarantee the global stability of the resulting closed-loop system, in the sense that all signals involved are uniformly bounded. The simulation results for a Duffing forced-oscillation system show better performances, i.e. tracking error and control effort can be made smaller.

Interference mitigation in point to point wireless sensor networks using LSP protocol and time division multiplexing approach

2020 ◽  
Vol 39 (4) ◽  
pp. 5449-5458
Author(s):  
A. Arokiaraj Jovith ◽  
S.V. Kasmir Raja ◽  
A. Razia Sulthana
Keyword(s):  
Energy Consumption ◽  
Large Scale ◽  
Control Parameter ◽  
Interference Mitigation ◽  
Wireless Sensor ◽  
Point To Point ◽  
A Minor ◽  
Two Stages ◽  
Time Division ◽  
And Control

Interference in Wireless Sensor Network (WSN) predominantly affects the performance of the WSN. Energy consumption in WSN is one of the greatest concerns in the current generation. This work presents an approach for interference measurement and interference mitigation in point to point network. The nodes are distributed in the network and interference is measured by grouping the nodes in the region of a specific diameter. Hence this approach is scalable and isextended to large scale WSN. Interference is measured in two stages. In the first stage, interference is overcome by allocating time slots to the node stations in Time Division Multiple Access (TDMA) fashion. The node area is split into larger regions and smaller regions. The time slots are allocated to smaller regions in TDMA fashion. A TDMA based time slot allocation algorithm is proposed in this paper to enable reuse of timeslots with minimal interference between smaller regions. In the second stage, the network density and control parameter is introduced to reduce interference in a minor level within smaller node regions. The algorithm issimulated and the system is tested with varying control parameter. The node-level interference and the energy dissipation at nodes are captured by varying the node density of the network. The results indicate that the proposed approach measures the interference and mitigates with minimal energy consumption at nodes and with less overhead transmission.

Using advanced control, post-denitrification and equalisation to improve the performance of a submerged filter

2000 ◽  
Vol 41 (4-5) ◽  
pp. 177-184 ◽  
Author(s):  
K.H. Sørensen ◽  
D. Thornberg ◽  
K.F. Janning
Keyword(s):  
Energy Consumption ◽  
Total N ◽  
Control Loops ◽  
Effluent Quality ◽  
Advanced Control ◽  
Before And After ◽  
And Control ◽  
Side Flow ◽  
Configuration Control ◽  
Control Post

In 1998, the capacity of the BIOSTYR® submerged biofilter at Nyborg WWTP was extended from 48,000 PE to 60,000 PE including advanced sensor based control, post-denitrification in BIOSTYR® and equalization of side flows. The existing configuration with 8 BIOSTYR® DN/N cells is based on pre-denitrification and an internal recirculation of 600–800%. The extended plant comprises 7 BIOSTYR® DN/N cells with 50–225% recirculation followed by 3 BIOSTYR DN cells for post-denitrification. The advanced control loops include blower control, control of the number of active cells (stand-by), automatic switch to high load configuration, control of the side flow equalization, control of the internal recirculation and control of the external carbon source dosing. In this paper, the achieved improvements are documented by comparing influent and effluent data, methanol and energy consumption from comparable periods before and after the extension. Although the nitrogen load to the plant was increased by 20% after the extension, the effluent quality has improved significantly with a reduction of Total-N from 7–8 mg/l to 3–4 mg/l. Simultaneously, the methanol consumption has been reduced by more than 50% per kg removed nitrogen. The energy consumption remained constant although the nitrogen load was increased by 20% and the inflow by 80%.

Probabilistic and Fuzzy based Efficient Routing Protocol for Mobile Ad Hoc Networks

2020 ◽  
Vol 13 (3) ◽  
pp. 422-432
Author(s):  
Madan Mohan Agarwal ◽  
Hemraj Saini ◽  
Mahesh Chandra Govil
Keyword(s):  
Fuzzy Logic ◽  
Energy Consumption ◽  
Routing Protocol ◽  
Queue Length ◽  
Ad Hoc ◽  
Fuzzy Controller ◽  
Second Phase ◽  
Path Distance ◽  
Fixed Threshold ◽  
Multiple Paths

Background: The performance of the network protocol depends on number of parameters like re-broadcast probability, mobility, the distance between source and destination, hop count, queue length and residual energy, etc. Objective: In this paper, a new energy efficient routing protocol IAOMDV-PF is developed based on the fixed threshold re-broadcast probability determination and best route selection using fuzzy logic from multiple routes. Methods: In the first phase, the proposed protocol determines fixed threshold rebroadcast probability. It is used for discovering multiple paths between the source and the destination. The threshold probability at each node decides the rebroadcasting of received control packets to its neighbors thereby reducing routing overheads and energy consumption. The multiple paths list received from the first phase and supply to the second phase that is the fuzzy controller selects the best path. This fuzzy controller has been named as Fuzzy Best Route Selector (FBRS). FBRS determines the best path based on function of queue length, the distance between nodes and mobility of nodes. Results: Comparative analysis of the proposed protocol named as "Improved Ad-Hoc On-demand Multiple Path Distance Vector based on Probabilistic and Fuzzy logic" (IAOMDV-PF) shows that it is more efficient in terms of overheads and energy consumption. Conclusion: The proposed protocol reduced energy consumption by about 61%, 58% and 30% with respect to FF-AOMDV, IAOMDV-F and FPAOMDV routing protocols, respectively. The proposed protocol has been simulated and analyzed by using NS-2.

An LQ Approach to Active Control of Vibrations in Helicopters

1996 ◽  
Vol 118 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Sergio Bittanti ◽  
Fabrizio Lorito ◽  
Silvia Strada
Keyword(s):  
Optimal Control ◽  
Active Control ◽  
Linear Quadratic ◽  
Control Effort ◽  
Vibration Effect ◽  
Suitable Definition ◽  
Lq Optimal Control ◽  
The One ◽  
Definition Of ◽  
And Control

In this paper, Linear Quadratic (LQ) optimal control concepts are applied for the active control of vibrations in helicopters. The study is based on an identified dynamic model of the rotor. The vibration effect is captured by suitably augmenting the state vector of the rotor model. Then, Kalman filtering concepts can be used to obtain a real-time estimate of the vibration, which is then fed back to form a suitable compensation signal. This design rationale is derived here starting from a rigorous problem position in an optimal control context. Among other things, this calls for a suitable definition of the performance index, of nonstandard type. The application of these ideas to a test helicopter, by means of computer simulations, shows good performances both in terms of disturbance rejection effectiveness and control effort limitation. The performance of the obtained controller is compared with the one achievable by the so called Higher Harmonic Control (HHC) approach, well known within the helicopter community.

scholarly journals Current Knowledge and Future Directions for Improving Subsoiling Quality and Reducing Energy Consumption in Conservation Fields

Agriculture ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 575
Author(s):  
Shangyi Lou ◽  
Jin He ◽  
Hongwen Li ◽  
Qingjie Wang ◽  
Caiyun Lu ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Cover Crops ◽  
Current Knowledge ◽  
High Energy ◽  
Field Application ◽  
Research Progress ◽  
Monitoring And Control ◽  
Future Directions ◽  
Tillage Depth ◽  
And Control

Subsoiling has been acknowledged worldwide to break compacted hardpan, improve soil permeability and water storage capacity, and promote topsoil deepening and root growth. However, there exist certain factors which limit the wide in-field application of subsoiling machines. Of these factors, the main two are poor subsoiling quality and high energy consumption, especially the undesired tillage depth obtained in the field with cover crops. Based on the analysis of global adoption and benefits of subsoiling technology, and application status of subsoiling machines, this article reviewed the research methods, technical characteristics, and developing trends in five key aspects, including subsoiling shovel design, anti-drag technologies, technologies of tillage depth detection and control, and research on soil mechanical interaction. Combined with the research progress and application requirements of subsoiling machines across the globe, current problems and technical difficulties were analyzed and summarized. Aiming to solve these problems, improve subsoiling quality, and reduce energy consumption, this article proposed future directions for the development of subsoiling machines, including optimizing the soil model in computer simulation, strengthening research on the subsoiling mechanism and comprehensive effect, developing new tillage depth monitoring and control systems, and improving wear-resisting properties of subsoiling shovels.

scholarly journals Endothelium as a Source and Target of H2S to Improve Its Trophism and Function

Antioxidants ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 486
Author(s):  
Valerio Ciccone ◽  
Shirley Genah ◽  
Lucia Morbidelli
Keyword(s):  
Endothelial Dysfunction ◽  
Vessel Wall ◽  
Redox Reactions ◽  
Single Layer ◽  
Fine Tuning ◽  
Therapeutic Approaches ◽  
Impaired Wound Healing ◽  
Blood Fluidity ◽  
And Function ◽  
And Control

The vascular endothelium consists of a single layer of squamous endothelial cells (ECs) lining the inner surface of blood vessels. Nowadays, it is no longer considered as a simple barrier between the blood and vessel wall, but a central hub to control blood flow homeostasis and fulfill tissue metabolic demands by furnishing oxygen and nutrients. The endothelium regulates the proper functioning of vessels and microcirculation, in terms of tone control, blood fluidity, and fine tuning of inflammatory and redox reactions within the vessel wall and in surrounding tissues. This multiplicity of effects is due to the ability of ECs to produce, process, and release key modulators. Among these, gasotransmitters such as nitric oxide (NO) and hydrogen sulfide (H2S) are very active molecules constitutively produced by endotheliocytes for the maintenance and control of vascular physiological functions, while their impairment is responsible for endothelial dysfunction and cardiovascular disorders such as hypertension, atherosclerosis, and impaired wound healing and vascularization due to diabetes, infections, and ischemia. Upregulation of H2S producing enzymes and administration of H2S donors can be considered as innovative therapeutic approaches to improve EC biology and function, to revert endothelial dysfunction or to prevent cardiovascular disease progression. This review will focus on the beneficial autocrine/paracrine properties of H2S on ECs and the state of the art on H2S potentiating drugs and tools.

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