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Search Results: 1 - 10 of 24128 matches for " control "
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Three-Level Control of a Distillation Column  [PDF]
László Szabó, Sándor Németh, Ferenc Szeifert
Engineering (ENG) , 2012, DOI: 10.4236/eng.2012.410086
Abstract: In this simulation study the operation of conventional distillation column (column with one feed and two products) was investigated with the application of AspenPlus DynamicsTM software. Control structures of the column which separate a two-component mixture were studied. The aim of our investigations was to discover dynamic and steady-state effects of heating and cooling on tray temperatures. The relationship of the tray temperatures and the purity of products were also identified. Based on the identified relationships a three level hierarchical control structure was developed. On the lowest level of the hierarchy there are the local controllers of heating and cooling. On the middle level of the control hierarchy the process variables are two tray temperatures and the output of the controllers is the set point of local controllers. On the top level of the control hierarchy the purity of the products are controlled over by manipulating the set point of the temperature controllers. This paper presents the functions of the control hierarchies and the middle level of the control hierarchy was analyzed in detail.
A Review of Control Algorithms for Autonomous Quadrotors  [PDF]
Andrew Zulu, Samuel John
Open Journal of Applied Sciences (OJAppS) , 2014, DOI: 10.4236/ojapps.2014.414053
Abstract: The quadrotor unmanned aerial vehicle is a great platform for control systems research as its nonlinear nature and under-actuated configuration make it ideal to synthesize and analyze control algorithms. After a brief explanation of the system, several algorithms have been analyzed including their advantages and disadvantages: PID, Linear Quadratic Regulator (LQR), Sliding mode, Backstepping, Feedback linearization, Adaptive, Robust, Optimal, L1, H, Fuzzy logic and Artificial neutral networks. The conclusion of this work is a proposal of hybrid systems to be considered as they combine advantages from more than one control philosophy.
An Adaptive Robust Approach to Modeling and Control of Flexible Arm Robots  [PDF]
Pedram Bagheri, Laleh Behjat, Qiao Sun
World Journal of Engineering and Technology (WJET) , 2018, DOI: 10.4236/wjet.2018.62017
Abstract: In this paper, a novel adaptive robust approach to modeling and control of a class of flexible-arm robots subject to actuators unmodeled dynamics is proposed. It is shown how real-time signals measured from a dynamical system can be utilized to improve the accuracy of the mathematical model of flexible robots. Given the elasticity of the robot’s arms, flexible manipulators have both passive and active degrees of freedom. A nonlinear robust controller is designed for the active degrees of freedom to enable the robot to follow desired trajectories in the presence of actuators unmodeled dynamics. Furthermore, it is shown that under some feasible conditions, another nonlinear robust controller is designed for the passive degrees of freedom. Moreover, to use the system response for model extraction, two auxiliary signals are proposed to provide sufficient information for improving the accuracy of the dynamics of the system numerically. Additionally, two adaptive laws are proposed in each case to update the two introduced auxiliary signals. As a result, the controller controls the passive degrees of freedom after the active degrees of freedom converge to their desired trajectories. Simultaneously, the information collected from the system to update the auxiliary signals enhances the model accuracy. In the end, simulation results are presented to verify the performance of the proposed controller.
Performance of Suboptimal Controllers for Affine-Quadratic Problems  [PDF]
Ankita Sharma, A. J. Shaiju
International Journal of Modern Nonlinear Theory and Application (IJMNTA) , 2014, DOI: 10.4236/ijmnta.2014.35025
Abstract: In this article, affine-quadratic control problems are studied. Error bounds are derived for the difference between the performance indices corresponding to the optimal and a class of suboptimal controls. In particular, it is shown that the performance of these suboptimal controls is close to that of the optimal control whenever the error in estimating the costate initial condition is small.
An Antilock-Braking Systems (ABS) Control: A Technical Review  [PDF]
Ayman A. Aly, El-Shafei Zeidan, Ahmed Hamed, Farhan Salem
Intelligent Control and Automation (ICA) , 2011, DOI: 10.4236/ica.2011.23023
Abstract: Many different control methods for ABS systems have been developed. These methods differ in their theoretical basis and performance under the changes of road conditions. The present review is a part of research project entitled “Intelligent Antilock Brake System Design for Road-Surfaces of Saudi Arabia” In the present paper we review the methods used in the design of ABS systems. We highlight the main difficulties and summarize the more recent developments in their control techniques. Intelligent control systems like fuzzy control can be used in ABS control to emulate the qualitative aspects of human knowledge with several advantages such as robustness, universal approximation theorem and rule-based algorithms.
An Integrated Control Strategy Adopting Droop Control with Virtual Inductance in Microgrid  [PDF]
Jianjun Su, Jieyun Zheng, Demin Cui, Xiaobo Li, Zhijian Hu, Chengxue Zhang
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.51B008
Abstract: As there exists sorts of distributed generators in microgrid, an integrated control strategy containing different control methods against corresponding generators should be applied. The strategy in this paper involves PQ control and droop control methods. The former aims at letting generators like PV output maximum power. The latter stems from inverter parallel technique and applies to controlling generators which can keep the network voltage steady to make the parallel system reach the minimum circulation point. Due to the unworthiness of droop control applied in low-voltage microgrid of which the impedance ratio is rather high, the paper adopts the droop control introducing virtual generator and virtual impedance. Based on theoretical analysis, simulation in Matlab is also implemented to verify the feasibility of the strategy.
Two Agent Paths Planning Collaboration Based on the State Feedback Stackelberg Dynamic Game  [PDF]
Sousso Kelouwani
Open Journal of Optimization (OJOp) , 2013, DOI: 10.4236/ojop.2013.23009

Autonomous Navigation Modules are capable of driving a robotic platform without human direct participation. It is usual to have more than one Autonomous Navigation Modules in the same work space. When an emergency situation occurs, these modules should achieve a desired formation in order to efficiently escape and avoid motion deadlock. We address the collaboration problem between two agents such as Autonomous Navigation Modules. A new approach for team collaborative control based on the incentive Stackelberg game theory is presented. The procedure to find incentive matrices is provided for the case of geometric trajectory planning and following. A collaborative robotic architecture based on this approach is proposed. Simulation results performed with two virtual robotic platforms show the efficiency of this approach.

A Stable Energy Saving Adaptive Control Scheme for Building Heating and Cooling Systems  [PDF]
Sumera I. Chaudhry, Manohar Das
Journal of Power and Energy Engineering (JPEE) , 2014, DOI: 10.4236/jpee.2014.25002

This paper presents a stable, nonlinear, adaptive control scheme for building heating and cooling systems. The proposed controller utilizes the principle of adaptive one step ahead control and aims at reducing the energy consumed for heating or cooling a building. The design steps are discussed in details and a proof of global stability is also provided. Also, the performance of the proposed controller is demonstrated on a simulated building thermal model.

Identification and low-complexity regime-switching insulin control of type I diabetic patients  [PDF]
Ali Hariri, Le Yi Wang
Journal of Biomedical Science and Engineering (JBiSE) , 2011, DOI: 10.4236/jbise.2011.44040
Abstract: This paper studies benefits of using simplified re-gime-switching adaptive control strategies in improving performance of insulin control for Type I diabetic patients. Typical dynamic models of glucose levels in diabetic patients are nonlinear. Using a linear time invariant controller based on an operating condition is a common method to simplify control design. On the other hand, adaptive control can potentially improve system performance, but it increases control complexity and may create further stability issues. This paper investigates patient models and presents a simplified switching control scheme using PID controllers. By comparing different switching schemes, it shows that switched PID controllers can improve performance, but frequent switching of controllers is unnecessary. These findings lead to a control strategy that utilizes only a small number of PID controllers in this scheduled adaptation strategy.
N-Removal on Wastewater Treatment Plants: A Process Control Approach  [PDF]
Ramon Vilanova, Reza Katebi, NoraLiza Wahab
Journal of Water Resource and Protection (JWARP) , 2011, DOI: 10.4236/jwarp.2011.31001
Abstract: A multilayered control design approach is proposed here. Starting with the Dissolved Oxygen (DO) control loop in the last aerated tank, the control of the recirculation sludge is added next. Once the limitations of this two-loop control strategy are highlighted, a cascade control loop is proposed. This cascade control is further enhanced by a feed-forward control action that makes use of influent ammonia concentration. The resulting cascade+feedforward control configuration achieves satisfactory nitrogen removal for the three influent operating conditions (dry, rain and storm.)
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