388 research outputs found

    Modeling and supervisory control design for a combined cycle power plant

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    The traditional control strategy based on PID controllers may be unsatisfactory when dealing with processes with large time delay and constraints. This paper presents a supervisory model based constrained predictive controller (MPC) for a combined cycle power plant (CCPP). First, a non-linear dynamic model of CCPP using the laws of physics was proposed. Then, the supervisory control using the linear constrained MPC method was designed to tune the performance of the PID controllers by including output constraints and manipulating the set points. This scheme showed excellent tracking and disturbance rejection results and improved performance compared with a stand-alone PID controller’s scheme

    The predictive functional control and the management of constraints in GUANAY II autonomous underwater vehicle actuators

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    Autonomous underwater vehicle control has been a topic of research in the last decades. The challenges addressed vary depending on each research group's interests. In this paper, we focus on the predictive functional control (PFC), which is a control strategy that is easy to understand, install, tune, and optimize. PFC is being developed and applied in industrial applications, such as distillation, reactors, and furnaces. This paper presents the rst application of the PFC in autonomous underwater vehicles, as well as the simulation results of PFC, fuzzy, and gain scheduling controllers. Through simulations and navigation tests at sea, which successfully validate the performance of PFC strategy in motion control of autonomous underwater vehicles, PFC performance is compared with other control techniques such as fuzzy and gain scheduling control. The experimental tests presented here offer effective results concerning control objectives in high and intermediate levels of control. In high-level point, stabilization and path following scenarios are proven. In the intermediate levels, the results show that position and speed behaviors are improved using the PFC controller, which offers the smoothest behavior. The simulation depicting predictive functional control was the most effective regarding constraints management and control rate change in the Guanay II underwater vehicle actuator. The industry has not embraced the development of control theories for industrial systems because of the high investment in experts required to implement each technique successfully. However, this paper on the functional predictive control strategy evidences its easy implementation in several applications, making it a viable option for the industry given the short time needed to learn, implement, and operate, decreasing impact on the business and increasing immediacy.Peer ReviewedPostprint (author's final draft

    Temperature profile control of a multiple hearth furnace for kaolin calcination

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    The main aim of this thesis is to develop a new temperature profile control strategy for kaolin calcination in the multiple hearth furnace (MHF) in order to improve the quality of the product. The overall control strategy for the MHF is developed as a three level control hierarchy: optimizing level, stabilizing level, and basic level. In the literature part of the thesis, first, the kaolin and its formation process is discussed. Next, the general information about calcination process is provided and the calcination of kaolin is discussed. Finally, few past researches having similar objective to this study are reviewed to study the various different control approaches developed so far and the possibility to implement them in our study. In the experimental part, analysis of the process is carried using the experimental data. During the data analysis, activation/ deactivation of the exothermic reaction in the hearth 4 is seen, which is crucial in determining the temperature profile of the furnace. Hence, the soft sensor based on the energy balance to estimate the intensity of the exothermic reaction, which plays a key role in developing the control strategy for the MHF, is developed. Both the static and dynamic energy balance equations are presented, calculated and compared in order to study the dynamic behaviour in the process. It is seen that the dynamic energy balance provides more accurate results than the static energy balance due to the consideration of the transition period

    Digital Embedding System with Heater and Cooler

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    Embedding is an anatomical pathology laboratory device that is very important for producing quality slices and is also a device used to process paraffin tissue, so that the tissue can be cut with higher precision using a microtom (slicer). From the process of melting paraffin crystals using a manual heating process with bunsen flame heaters (fire heaters) so that the paraffin crystals can be transformed from the crystal into liquid. While paraffin crystals that have been processed from the crystal to liquid form are poured into the mold and left to freeze. In this case, an embedding system device will be made equipped with heating and cooling. The temperature used for the liquefaction process is 50C while the temperature for cooling is 17C. After making the process of making device, experiment device, and retrieving data, the error percentage results were 0.016% at the heating temperature and 0.08% at the coolant temperature, and the percentage of heating samples obtained in the sample was 61.3%, while the percentage samples for parts coolers get a value of 92

    Impact of Embedded Carbon Fiber Heating Panel on the Structural/Mechanical Performance of Roadway Pavement

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    INE/AUTC 12.3

    Development of Fuzzy Logic Based Temperature Controller for Dialysate Preparation System

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    Preparing the dialysate temperature to the desiredlevel is a complicated task, since it has a large degree of time delayand nonlinear behaviour. In this work, embedded system fordialysate temperature controller was developed. It is based onimplementation of fuzzy logic controller software on STM32 F4development kit which consits of ARM Cortex M4Fmicrocontroller. The dialysate temperature was controlled byvarying the firing angle of the triac which is connected to theheater. The K-type thermocouple which is connected to AD595CQwas read and compared with the desire dialysate temperature.The fuzzification process was conducted prior to activate the fuzzyinference process. The power of the heater was adjusted based onthe output of the inference process until the desired watertemperatur was achieved. The system had been sucessfullydemonstrated for controlling the dialysate temperature

    Detailed model for robust feedback design of main steam temperatures in coal fired boilers

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    Main steam temperatures play a significant role in large coal fired power plant operation. Ideally, main steam temperatures should be accurately controlled to protect the thick wall components against long term overheating and thermal stress while meeting the design conditions at the steam turbine inlet. Although high steam temperatures are beneficial for thermal efficiency, it accelerates creep damage in high temperature components which is detrimental to the life of components. Alternatively, low steam temperatures increase the moisture content at the last stage blades of the turbine, causing the blades to deteriorate and fail. Control of the outlet steam temperature according to design conditions at variable loads is maintained via a balance between heat input (flue gas temperature and mass flow rate), evaporator outlet steam mass flow and spray water. The present control philosophy accuracy of main steam temperatures at an Eskom coal fired power plant was evaluated and compared to the latest technology and control strategies. Improving and optimizing steam temperature controls ensures design efficiency while maintaining long term plant health. The level of spatial discretization applied in simplifying the real boiler for modelling purposes was approached at a relatively high level. The intention was to model normal operating conditions and certain transients such as variable heat input and load changes to see its effect on steam temperatures and to be able to evaluate the performance of different temperature control techniques. The main outcome of this project was to design a robust control system for a dynamic model of the boiler using sets of low order linear models to account for uncertainty. The main concepts, models and theories used in the development of this dissertation include: 1) A detailed thermo-fluid model developed using Flownex to have high fidelity models of the process under varying operating conditions. This model was used to test and evaluate the robust controller design. 2) System Identification in Matlab to construct mathematical models of dynamic systems from measured inputoutput data and identify linear continuous time transfer functions under all operating conditions [1]. 3) Quantitative Feedback Theory (QFT) to design controllers for an attemperator control system at various onload operating conditions. This design was used understand the engineering requirements and seeks to design fixed gain controllers that will give desired performance under all operating conditions. 4) The design of a valve position controller to increase the heat uptake in a convective pass, thereby improving efficiency: Excessive attemperation in the superheater passes is generally associated with high flue gas temperatures which decrease thermal efficiency. Therefore, robust control of the attemperation system leads to an increase in heat uptake between the flue gas and steam in the boiler, resulting in a reduction in the flue gas temperature leaving the boiler, thus improving efficiency. The robust QFT controllers were set up using the valve position control technique and were used to confirm the improvement of control performance. The theories mentioned above were used to understand the control performance under varying plant conditions using a standard cascaded arrangement. It incorporated robust control design and engineering requirements such as bandwidth, plant life, spray water and thermodynamic efficiency. The control effort allocated to each superheaterattemperator subsystem in the convective pass was designed as a multi-loop problem

    Fractional-Order PID Controllers for Temperature Control:A Review

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    Fractional-order proportional integral derivative (FOPID) controllers are becoming increasingly popular for various industrial applications due to the advantages they can offer. Among these applications, heating and temperature control systems are receiving significant attention, applying FOPID controllers to achieve better performance and robustness, more stability and flexibility, and faster response. Moreover, with several advantages of using FOPID controllers, the improvement in heating systems and temperature control systems is exceptional. Heating systems are characterized by external disturbance, model uncertainty, non-linearity, and control inaccuracy, which directly affect performance. Temperature control systems are used in industry, households, and many types of equipment. In this paper, fractional-order proportional integral derivative controllers are discussed in the context of controlling the temperature in ambulances, induction heating systems, control of bioreactors, and the improvement achieved by temperature control systems. Moreover, a comparison of conventional and FOPID controllers is also highlighted to show the improvement in production, quality, and accuracy that can be achieved by using such controllers. A composite analysis of the use of such controllers, especially for temperature control systems, is presented. In addition, some hidden and unhighlighted points concerning FOPID controllers are investigated thoroughly, including the most relevant publications

    PID Control Design for Biofuel Furnace using Arduino

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    The target of the Indonesian government in 2025 is increasing the use of renewable energy up to 23%, one part of potential renewable energy in Indonesia is biofuel. Biofuel requires raw materials of plant or animal oil with or without catalyst, it does not require the raw material of ethanol or methanol. The product is similar to gasoline and diesel that came from crude oil. Potential oil-producing plants in Indonesia are Palm Oil and Nyamplung (Calophyllum inophyllum L.). The process of making biofuel from this material is done by heating the reactor or furnace with temperature range of 350° C - 500° C. To reach the stability of furnace temperature, it requires temperature control systems and one of them is PID. Arduino microcontroller is an open source and user friendly platform for hardware and software. The control system that designed by using arduino is capable to control the furnace temperature from 200° C to 400° C and it is using a 6000 watt heater. The best system response is achieved when Kp = 15, Ki = 15 and Kd = 1. With these parameter values, the system has the lowest overshoot response of 16%, so it is safe for biofuel furnace, even though the rise time value is 146 s, settling time of 429 and steady state error is equal to 2.87%

    Variable structure controller for plastic injection moulding system

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    This paper discusses the approach to design of combined ANN and PID temperature controller for a plastic injection moulding system. The proposed method is based on integration of a conventional PID (PI) controller and a multilayer ANN. At the initial stage of operation, the ANN is trained in offline mode to approximately identify the dynamic parameters of the regulator optimised in terms of speed of response and overshoot. Under routine operation mode the ANN control structure is responsible for the fast transients whereas PID (PI) controller provides the high accuracy at the steady state condition. The paper focuses on the structure switching mechanism and the influence on the transient accuracy. In order to verify the proposed approach, the control system having various types of heaters has been modelled and simulated in Matlab/Simulink. The data obtained from the experiment verified the developed model and confirmed the results of simulations
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