Journal articles on the topic 'Nonlinear static state feedback controller (NSSFC)'
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1
Liu, Long, and Ming Li. "Dissipative Control for Nonlinear Neutral Delay Systems." Applied Mechanics and Materials 48-49 (February 2011): 439–42. http://dx.doi.org/10.4028/www.scientific.net/amm.48-49.439.
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The problem of delay-dependent dissipative control for nonlinear neutral delay systems is dealt with. We develop the design method of dissipative static state feedback controller such that the closed-loop system is absolutely stable and strictly-dissipative. Sufficient conditions for the existence of the quadratic dissipative controller are obtained by using linear Matrix Inequality(LMI) approach. Furthermore, a procedure of constructing such a controller from the solution of LMI is given. It is shown that the solvability of a dissipative controller design is implied by the feasibility of LMIs.
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Gao, Peng, Guangming Zhang, Huimin Ouyang, and Lei Mei. "A Sliding Mode Control with Nonlinear Fractional Order PID Sliding Surface for the Speed Operation of Surface-Mounted PMSM Drives Based on an Extended State Observer." Mathematical Problems in Engineering 2019 (September 18, 2019): 1–13. http://dx.doi.org/10.1155/2019/7130232.
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A novel sliding mode controller (SMC) with nonlinear fractional order PID sliding surface based on a novel extended state observer for the speed operation of a surface-mounted permanent magnet synchronous motor (SPMSM) is proposed in this paper. First, a new smooth and derivable nonlinear function with improved continuity and derivative is designed to replace the traditional nonderivable nonlinear function of the nonlinear state error feedback control law. Then, a nonlinear fractional order PID sliding mode controller is proposed on the basis of the fractional order PID sliding surface with the combination of the novel nonlinear state error feedback control law to improve dynamic performance, static performance, and robustness of the system. Furthermore, a novel extended state observer is designed based on the new nonlinear function to achieve dynamic feedback compensation for external disturbances. Stability of the system is proved based on the Lyapunov stability theorem. The corresponding comparative simulation results demonstrate that the proposed composite control algorithm displays good stability, dynamic properties, and strong robustness against external disturbances.
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Zhang, Yan, Yali Dong, and Tianrui Li. "Design of Robust Output Feedback Guaranteed Cost Control for a Class of Nonlinear Discrete-Time Systems." International Journal of Engineering Mathematics 2014 (September 10, 2014): 1–9. http://dx.doi.org/10.1155/2014/628041.
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This paper investigates static output feedback guaranteed cost control for a class of nonlinear discrete-time systems where the delay in state vector is inconsistent with the delay in nonlinear perturbations. Based on the output measurement, the controller is designed to ensure the robust exponentially stability of the closed-loop system and guarantee the performance of system to achieve an adequate level. By using the Lyapunov-Krasovskii functional method, some sufficient conditions for the existence of robust output feedback guaranteed cost controller are established in terms of linear matrix inequality. A numerical example is provided to show the effectiveness of the results obtained.
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Yu, Xiao, Fucheng Liao, and Jiamei Deng. "Robust Preview Control for a Class of Uncertain Discrete-Time Lipschitz Nonlinear Systems." Mathematical Problems in Engineering 2018 (September 10, 2018): 1–15. http://dx.doi.org/10.1155/2018/4606389.
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This paper considers the design of the robust preview controller for a class of uncertain discrete-time Lipschitz nonlinear systems. According to the preview control theory, an augmented error system including the tracking error and the known future information on the reference signal is constructed. To avoid static error, a discrete integrator is introduced. Using the linear matrix inequality (LMI) approach, a state feedback controller is developed to guarantee that the closed-loop system of the augmented error system is asymptotically stable with H∞ performance. Based on this, the robust preview tracking controller of the original system is obtained. Finally, two numerical examples are included to show the effectiveness of the proposed controller.
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Lukov, V., M. Alexandrova, and N. Nikolov. "Multi-model Fuzzy Modal Control of SISO Nonlinear Plant." Information Technologies and Control 14, no. 4 (December 1, 2016): 19–26. http://dx.doi.org/10.1515/itc-2017-0013.
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Abstract The article presents the synthesis of a multi-model modal control of single input – single output nonlinear plant, based on Takagi-Sugeno fuzzy controller. For that purpose, the nonlinear static characteristic of the plant is presented by two linear parts. These two linear structures are described in state space. The feedback vectors and the coefficients ki of the modal controllers are calculated. An integral component in the control law is added.
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Li, Li, Qingling Zhang, Yi Zhang, and Baoyan Zhu. "H∞Fuzzy Control for Nonlinear Singular Markovian Jump Systems with Time Delay." Mathematical Problems in Engineering 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/896515.
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This paper investigates the problem ofH∞fuzzy control for a class of nonlinear singular Markovian jump systems with time delay. This class of systems under consideration is described by Takagi-Sugeno (T-S) fuzzy models. Firstly, sufficient condition of the stochastic stabilization by the method of the augmented matrix is obtained by the state feedback. And a designed algorithm for the state feedback controller is provided to guarantee that the closed-loop system not only is regular, impulse-free, and stochastically stable but also satisfies a prescribedH∞performance for all delays not larger than a given upper bound in terms of linear matrix inequalities. ThenH∞fuzzy control for this kind of systems is also discussed by the static output feedback. Finally, numerical examples are given to illustrate the validity of the developed methodology.
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Guo, Longchuan, Chuanping Zhou, Xiaoqing Tian, Huawei Ji, and Yudong Peng. "Design of Constructive Controller of Nonlinear System Based on Polynomial Function Growth Condition and Its Application in Deep Subsea Energy Mining and Production Control System." Advances in Civil Engineering 2021 (October 7, 2021): 1–9. http://dx.doi.org/10.1155/2021/4788428.
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This paper mainly studies the output feedback control problem of the stochastic nonlinear system based on loose growth conditions and applies the research results to the valve control system of underwater oil and gas pipelines, which can improve the speed and stability of the equipment system. First, the concept of randomness is introduced to study the actual tracking control problem of output feedback of stochastic nonlinear systems, remove the original harsher growth conditions, make it meet the more general polynomial function growth conditions, and propose a combination of static and dynamic output feedback practices. The design of the tracking controller makes all the states of the system meet boundedness and ensures that the tracking error of the system converges to a small neighborhood of zero. Second, the system is extended to the parameter-uncertain system, and the output feedback tracking controller with complete dynamic gain is constructed by proving the boundedness of the system state and gain. Further, the time-delay factor is introduced, and the nonlinear term of the system satisfies the more relaxed power growth condition, combined with the inverse method to cleverly construct a set of Lyapunov functions and obtain the output controller to ensure that the system is asymptotically probabilistic in the global scope. Stability. Finally, through the ocean library in the Simulation X simulation software, the controller design results are imported into the underwater electro-hydraulic actuator model to verify the effectiveness of the controller design.
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Zhang, Yu Hui, Chang Bing Han, and Tian Yun Li. "Sliding Mode Variable Structure for Generator Excitation Control Based on the ESO." Applied Mechanics and Materials 143-144 (December 2011): 108–13. http://dx.doi.org/10.4028/www.scientific.net/amm.143-144.108.
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In this paper, a new ESO sliding mode controller that can improve the system stability was designed ,as to the strong nonlinear of generator excitation system and the characteristics of vulnerable to external disturbance, which application of feedback linearization, ESO and sliding model variable structure control theory. Firstly, it realized to linearization for nonlinear mould based on the feedback linearization theory, then it provide dynamic compensation for generator excitation system through constructing extended state observation device (ESO). The methods of factorial is used to design sliding mode switch function, theoretically, it guarantee generator rotor equation with expectations of poles. In order to reduce chattering ,through index near rate and quasi sliding mode control dynamic method to get the sliding control rate, it make the form conciseness, The results of simulation show that the speed , accuracy and stability of system are significantly improved by controller in dynamic and static . Introduction
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Saeedian, Atefeh, Farshad Merrikh-Bayat, and Abolfazl Jalilvand. "Multivariable fractional-order PID tuning by iterative non-smooth static-dynamic H∞ synthesis." Fractional Calculus and Applied Analysis 24, no. 4 (August 1, 2021): 1094–111. http://dx.doi.org/10.1515/fca-2021-0047.
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Abstract This paper proposes a new method for tuning the parameters of multi-input multi-output (MIMO) fractional-order PID (FOPID) controller. The aim of the proposed method is to calculate the parameters of this controller such that the rise time and steady-state errors of the feedback system are minimized without violating the predetermined stability margins. Mathematically, this problem is formulated as maximizing the spectral norm of the open-loop transfer matrix at zero frequency subject to a constraint on the H∞ -norm of the sensitivity function. This problem is nonlinear in parameters of the MIMO FOPID, which can be solved using the iterative algorithm developed in this paper based on non-smooth H∞ synthesis.
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Zhu, De Hong, Rong Xu, Li Hu Lu, and Hai Juan Liu. "Research on Nonlinear Control of AC Active Magnetic Bearings." Advanced Materials Research 562-564 (August 2012): 968–74. http://dx.doi.org/10.4028/www.scientific.net/amr.562-564.968.
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For the five degree-of-freedom (5-DOF) AC active magnetic bearing (AMB), which is a multivariable, nonlinear and strongly coupled system, conventional single-variable controller cannot meet the control requirements. Based on the state space model of 5-DOF AC AMB and direct feedback linearization, the equations of coordinate transform and nonlinear state feedback can be simplified into differentiating output equations, which achieves the input-output linearization of 5-DOF AC AMB system. Then, the system can be decoupled into five independent 2-order linear subsystems and realizes the completely decoupling of 5-DOF. Finally, the internal model control (IMC) method is employed to synthesize the subsystems, in order to avoid the performance deteriorated due to the model error and external disturbance. The results of simulation example demonstrate that this decoupling control strategy can realize not only the dynamic decoupling of 5-DOF AC AMB, but also the good dynamic/static performance and robustness.
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Kanchanaharuthai, Adirak, Piraporn Konkhum, and Kruwan Wongsurith. "A Composite Nonlinear Controller for Power Systems with STATCOM under External Disturbances." ECTI Transactions on Electrical Engineering, Electronics, and Communications 18, no. 2 (August 31, 2020): 107–17. http://dx.doi.org/10.37936/ecti-eec.2020182.240342.
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This paper concentrates on the design of a composite nonlinear stabilizing state feedback control for power systems with static synchronous compensator (STATCOM) with the help of a combination of backstepping strategy and a nonlinear disturbance approach. The disturbance observer is used to estimate unavoidably external disturbances. Thus, the obtained control law can be used to successfully stabilize the system stability and reject undesired external disturbances. In order to demonstrate the effectiveness of the developed process design, numerical simulation results are provided to indicate that the presented composite controller can improve dynamic performances, rapidly suppress system oscillations of the overall closed-loop dynamics, and despite having inevitably external disturbances, performs better than a conventional backstepping control technique.
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Rigatos, Gerasimos G., and Guilherme V. Raffo. "Input–Output Linearizing Control of the Underactuated Hovercraft Using the Derivative-Free Nonlinear Kalman Filter." Unmanned Systems 03, no. 02 (April 2015): 127–42. http://dx.doi.org/10.1142/s2301385015500089.
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The paper proposes a nonlinear control approach for the underactuated hovercraft model based on differential flatness theory and uses a new nonlinear state vector and disturbances estimation method under the name of derivative-free nonlinear Kalman filter. It is proven that the nonlinear model of the hovercraft is a differentially flat one. It is shown that this model cannot be subjected to static feedback linearization, however it admits dynamic feedback linearization which means that the system's state vector is extended by including as additional state variables the control inputs and their derivatives. Next, using the differential flatness properties it is also proven that this model can be subjected to input–output linearization and can be transformed to an equivalent canonical (Brunovsky) form. Based on this latter description the design of a state feedback controller is carried out enabling accurate maneuvering and trajectory tracking. Additional problems that are solved in the design of this feedback control scheme are the estimation of the nonmeasurable state variables in the hovercraft's model and the compensation of modeling uncertainties and external perturbations affecting the vessel. To this end, the application of the derivative-free nonlinear Kalman filter is proposed. This nonlinear filter consists of the Kalman Filter's recursion on the linearized equivalent model of the vessel and of an inverse nonlinear transformation based on the differential flatness features of the system which enables to compute estimates for the state variables of the initial nonlinear model. The redesign of the filter as a disturbance observer makes possible the estimation and compensation of additive perturbation terms affecting the hovercraft's model. The efficiency of the proposed nonlinear control and state estimation scheme is confirmed through simulation experiments.
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Benyamina, Mansour, Ali Tahri, and Abdelkader Boukortt. "State feedback control of advanced static var compensator using a five-level NPC inverter topology." International Journal of Power Electronics and Drive Systems (IJPEDS) 12, no. 1 (March 1, 2021): 345. http://dx.doi.org/10.11591/ijpeds.v12.i1.pp345-355.
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This paper deals with the modeling and control of an advanced static var compensator (ASVC) using a five-level neutral point-clamped (NPC) voltage source inverter (VSI). The nonlinear state space model of the five-level ASVC is obtained from the d-q axis frame. The effectiveness of this compensator highly depends on the choice of the control strategy. The proposed state feedback control (SFC) technique is applied to adjust the ASVC Var flow with the AC transmission network and achieve DC voltage capacitor balance. The dynamic performance of the ASVC based SFC controller is evaluated under several operating conditions. The simulation results demonstrate that the proposed SFC control strategy is highly robust compared to the conventional Proportional-Integral (PI) control.
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Alkurawy, Lafta E. J., Adham H. Saleh, and Ibraheem S. Fatah. "ROBUST AND FEEDFORWARD CONTROL FOR A NONLINEAR PNEUMATIC SERVOMECHANISM SYSTEM." Journal of Southwest Jiaotong University 56, no. 5 (October 30, 2021): 362–69. http://dx.doi.org/10.35741/issn.0258-2724.56.5.31.
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The actuator of the vane servo unit epitomizes the control operator of force in systems of missile control, where the character of its dynamic and static plays a significant role in the missile behavior. Therefore, improving the dynamic behavior for the vane servo actuator is of main interest for designing control and guidance system. The article describes a new method of analyzing the mathematical model of the nonlinear pneumatic servo with different design parameters and designing a controller with these parameters. The robust control regulates the system with different parameters, and it is the first controller to attempt this technique. A servo actuator of nonlinear and linear simulators was constructed by MATLAB software package. Feedback controllers with PI and PID were designed and tested theoretically. The setting time and the behavior of the dynamic will be improved. The robust feedforward control was applied to the system to improve the stability and zero steady-state error and compare the results with PI and PID controller. Their tests showed that robust control is the best control for stability among the others.
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Kadhem, Basim. "Using a Reduced Order Robust Control Approach to Damp Subsynchronous Resonance in Power Systems." Iraqi Journal for Electrical and Electronic Engineering 19, no. 1 (December 1, 2022): 29–37. http://dx.doi.org/10.37917/ijeee.19.1.4.
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his work focuses on the use of the Linear Quadratic Gaussian (LQG) technique to construct a reliable Static VAr Compensator (SVC), Thyristor Controlled Series Compensator (TCSC), and Excitation System controller for damping Subsynchronous Resonance ( SSR ) in a power system. There is only one quantifiable feedback signal used by the controller (generator speed deviation). It is also possible to purchase this controller in a reduced-order form. The findings of the robust control are contrasted with those of the “idealistic” full state optimal control. The LQG damping controller’s regulator robustness is then strengthened by the application of Loop Transfer Recovery (LTR). Nonlinear power system simulation is used to confirm the resilience of the planned controller and demonstrates how well the regulator dampens power system oscillations. The approach dampens all torsional oscillatory modes quickly while maintaining appropriate control actions, according to simulation results.
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Rsetam, Kamal, Yusai Zheng, Zhenwei Cao, and Zhihong Man. "Adaptive Active Disturbance Rejection Control for Vehicle Steer-by-Wire under Communication Time Delays." Applied System Innovation 7, no. 2 (March 8, 2024): 22. http://dx.doi.org/10.3390/asi7020022.
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In this paper, an adaptive active disturbance rejection control is newly designed for precise angular steering position tracking of the uncertain and nonlinear SBW system with time delay communications. The proposed adaptive active disturbance rejection control comprises the following two elements: (1) An adaptive extended state observer and (2) an adaptive state error feedback controller. The adaptive extended state observer with adaptive gains is employed for estimating the unmeasured velocity, acceleration, and compound disturbance which consists of system parameter uncertainties, nonlinearities, exterior disturbances, and time delay in which the observer gains are dynamically adjusted based on the estimation error to enhance estimation performances. Based on the accurate estimations of the adaptive extended state observer, the proposed adaptive full state error feedback controller is equipped with variable gains driven by the tracking error to develop control precision. The integration of the advantages of the adaptive extended state observer and the adaptive full state error feedback controller can improve the dynamic transient and static steady-state effectiveness, respectively. To assess the superior performance of the proposed adaptive active disturbance rejection control, a comparative analysis is conducted between the proposed control scheme and the classical active disturbance rejection control in two different cases. It is worth noting that the active disturbance rejection control serves as a benchmark for evaluating the performance of the proposed control approach. The results from the comparison studies executing two simulated cases validate the superiority of the suggested control, in which estimation, tracking response rate, and steering angle precision are greatly improved by the scheme proposed in this article.
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Pandey, Vinay, Eram Taslima, Bhawana Singh, Shyam Kamal, and Thach Ngoc Dinh. "Predefined Time Synchronization of Multi-Agent Systems: A Passivity Based Analysis." Sensors 23, no. 8 (April 10, 2023): 3865. http://dx.doi.org/10.3390/s23083865.
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This paper deals with the predefined-time synchronization for a class of nonlinear multi-agent systems. The notion of passivity is exploited to design the controller for predefined-time synchronization of a nonlinear multi-agent system, where the time of synchronization can be preassigned. Developed control can be used to synchronize large-scale, higher-order multi-agent systems as passivity is an important property in designing control for complex control systems, where the control inputs and outputs are considered in determining the stability of the system in contrast to other approaches, such as state-based Control We introduced the notion of predefined-time passivity and as an application of the exposed stability analysis, static and adaptive predefined-time control algorithms are designed to study the average consensus problem for nonlinear leaderless multiagent systems in predefined-time. We provide a detailed mathematical analysis of the proposed protocol, including convergence proof and stability analysis. We discussed the tracking problem for a single agent, and designed state feedback and adaptive state feedback control scheme to make tracking error predefined-time passive and then showed that in the absence of external input, tracking error reduces to zero in predefined-time. Furthermore, we extended this concept for a nonlinear multi-agent system and designed state feedback and adaptive state feedback control scheme which ensure synchronization of all the agents in predefined-time. To further strengthen the idea, we applied our control scheme to a nonlinear multi-agent system by taking the example of Chua’s circuit. Finally, we compared the result of our developed predefined-time synchronization framework with finite-time synchronization scheme available in literature for the Kuramoto model.
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Qu, Ying, Bin Zhang, Hairong Chu, Xiaoxia Yang, Honghai Shen, and Jingzhong Zhang. "Linear-Nonlinear Switching Active Disturbance Rejection Speed Controller for Permanent Magnet Synchronous Motors." Sensors 22, no. 24 (December 8, 2022): 9611. http://dx.doi.org/10.3390/s22249611.
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To combine the advantages of linear active disturbance rejection control (LADRC) and nonlinear active disturbance rejection control (NLADRC) and improve the contradiction between the response speed and control precision caused by the limitation of parameter α in NLADRC, a linear-nonlinear switching active disturbance rejection control (SADRC) strategy based on linear-nonlinear switching extended state observer (SESO) and linear-nonlinear switching state error feedback control law (SSEF) is proposed in this paper. First, the reasons for the performance differences between LADRC and NLADRC are analysed from a theoretical point of view, then a linear-nonlinear switching function (SF) that can change the switching point by adjusting its parameters is constructed and then propose SESO and SSEF based on this function. Subsequently, the convergence range of the observation error of the SESO is derived, and the stability of the closed-loop system with the application of SSEF is also demonstrated. Finally, the proposed SADRC control strategy is applied to a 707 W permanent magnet synchronous motor (PMSM) experimental platform, and both the dynamic and static characteristics of SADRC are verified. The experimental results show that the proposed SADRC control strategy can well combine the performance advantages of LADRC and NLADRC and can better balance the response speed and control precision and has a better capacity for disturbance rejection, which has potential application in engineering practise.
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Luo, Dong Song, Xin Ke Hu, and Yi Wei Feng. "Stability Analysis of Quantized Feedback Control System." Advanced Materials Research 605-607 (December 2012): 1845–50. http://dx.doi.org/10.4028/www.scientific.net/amr.605-607.1845.
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This paper studies the feedback control problem of nonlinear systems in strict-feedback form with state quantizers, which are static and bounded by sectors. Through a newly developed and versatile Lyapunov function analyzing approach for networked and quantized control systems (NQCSs). The common aim is to demonstrate that a unified study of quantization and delay effects in an uncertain system is possible by merging the quantized control law. A new delays-independent stability criterion is derived in terms of linear matrix inequality (LMI) which can be easily solved. This paper describes a system for the stability analysis of the uncertain systems subject to quantization and time-delay. Moreover, a sufficient condition for the existence of a guaranteed cost controller for NCSs is also presented by a set of LMIs. Both theoretical analysis and numerical examples show that the results in this paper are generally less conservative than those in the quadratic framework.
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Rajendran, Saravanakumar, and Debashisha Jena. "Load Mitigation and Optimal Power Capture for Variable Speed Wind Turbine in Region 2." Journal of Renewable Energy 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/978216.
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This paper proposes the two nonlinear controllers for variable speed wind turbine (VSWT) operating at below rated wind speed. The objective of the controller is to maximize the energy capture from the wind with reduced oscillation on the drive train. The conventional controllers such as aerodynamic torque feedforward (ATF) and indirect speed control (ISC) are adapted initially, which introduce more power loss, and the dynamic aspects of WT are not considered. In order to overcome the above drawbacks, modified nonlinear static state with feedback estimator (MNSSFE) and terminal sliding mode controller (TSMC) based on Modified Newton Raphson (MNR) wind speed estimator are proposed. The proposed controllers are simulated with nonlinear FAST (fatigue, aerodynamics, structures, and turbulence) WT dynamic simulation for different mean wind speeds at below rated wind speed. The frequency analysis of the drive train torque is done by taking the power spectral density (PSD) of low speed shaft torque. From the result, it is found that a trade-off is to be maintained between the transient load on the drive train and maximum power capture.
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Zhang, Haojiong, and Robert G. Landers. "Precision Motion Control Methodology for Complex Contours." Journal of Manufacturing Science and Engineering 129, no. 6 (June 6, 2007): 1060–68. http://dx.doi.org/10.1115/1.2769728.
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A general precision motion control methodology for complex contours is proposed in this paper. Each motion servomechanism dynamic model is divided into a linear portion and a portion containing nonlinear friction, unmodeled dynamics, and unknown disturbances. A full state feedback controller, based on a state space error system model, is developed to track general reference trajectories. The lumped static, Coulomb, and Stribeck friction effects are described using the Tustin friction model. Unmodeled dynamics and unknown disturbances are estimated using a Kalman filter that employs a first-order stochastic model. The nonlinear friction, unmodeled dynamics, and unknown disturbances are directly canceled by the controller. In the proposed motion control methodology, complex contours (i.e., contours whose radii of curvature constantly change along the contour) do not need to be decomposed into line segments and arcs and the reference signals do not need to be prefiltered. Also, the controller structure does not need to be adjusted to track different types of contours. Experiments are conducted on a two-axis laboratory grade machine tool for elliptical, limacon, and free-form contours. The results demonstrate the excellent tracking performance of the proposed motion control methodology. They also demonstrate that the performance is independent of the contours’ complexity.
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An, Chao, Chao Yang, Changchuan Xie, and Yang Meng. "Gust Load Alleviation including Geometric Nonlinearities Based on Dynamic Linearization of Structural ROM." International Journal of Aerospace Engineering 2019 (May 12, 2019): 1–20. http://dx.doi.org/10.1155/2019/3207912.
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This paper describes a framework for an active control technique applied to gust load alleviation (GLA) of a flexible wing, including geometric nonlinearities. Nonlinear structure reduced order model (ROM) and nonplanar double-lattice method (DLM) are used for structural and aerodynamic modeling. The structural modeling method presented herein describes stiffness nonlinearities in polynomial formulation. Nonlinear stiffness can be derived by stepwise regression. Inertia terms are constant with linear approximation. Boundary conditions and kernel functions in the nonplanar DLM are determined by structural deformation to reflect a nonlinear effect. However, the governing equation is still linear. A state-space equation is established in a dynamic linearized system around the prescribed static equilibrium state after nonlinear static aeroelastic analysis. Gust response analysis can be conducted subsequently. For GLA analysis, a classic proportional-integral-derivative (PID) controller treats a servo as an actuator and acceleration as the feedback signal. Moreover, a wind tunnel test has been completed and the effectiveness of the control technology is validated. A remote-controlled (RC) model servo is chosen in the wind tunnel test. Numerical simulation results of gust response analysis reach agreement with test results. Furthermore, the control system gives GLA efficacy of vertical acceleration and root bending moment with the reduction rate being over 20%. The method described in this paper is suitable for gust response analysis and control strategy design for large flexible wings.
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Spong, M. W. "Modeling and Control of Elastic Joint Robots." Journal of Dynamic Systems, Measurement, and Control 109, no. 4 (December 1, 1987): 310–18. http://dx.doi.org/10.1115/1.3143860.
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In this paper we study the modeling and control of robot manipulators with elastic joints. We first derive a simple model to represent the dynamics of elastic joint manipulators. The model is derived under two assumptions regarding dynamic coupling between the actuators and the links, and is useful for cases where the elasticity in the joints is of greater significance than gyroscopic interactions between the motors and links. In the limit as the joint stiffness tends to infinity, our model reduces to the usual rigid model found in the literature, showing the reasonableness of our modeling assumptions. We show that our model is significantly more tractable with regard to controller design than previous nonlinear models that have been used to model elastic joint manipulators. Specifically, the nonlinear equations of motion that we derive are shown to be globally linearizable by diffeomorphic coordinate transformation and nonlinear static state feedback, a result that does not hold for previously derived models of elastic joint manipulators. We also detail an alternate approach to nonlinear control based on a singular perturbation formulation of the equations of motion and the concept of integral manifold. We show that by a suitable nonlinear feedback, the manifold in state space which describes the dynamics of the rigid manipulator, that is, the manipulator without joint elasticity, can be made invariant under solutions of the elastic joint system. The implications of this result for the control of elastic joint robots are discussed.
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Alam, Umme Kawsar, Kassidy Shedd, and Mahdi Haghshenas-Jaryani. "Trajectory Control in Discrete-Time Nonlinear Coupling Dynamics of a Soft Exo-Digit and a Human Finger Using Input–Output Feedback Linearization." Automation 4, no. 2 (May 31, 2023): 164–90. http://dx.doi.org/10.3390/automation4020011.
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This paper presents a quasi-static model-based control algorithm for controlling the motion of a soft robotic exo-digit with three independent actuation joints physically interacting with the human finger. A quasi-static analytical model of physical interaction between the soft exo-digit and a human finger model was developed. Then, the model was presented as a nonlinear discrete-time multiple-input multiple-output (MIMO) state-space representation for the control system design. Input–output feedback linearization was utilized and a control input was designed to linearize the input–output, where the input is the actuation pressure of an individual soft actuator, and the output is the pose of the human fingertip. The asymptotic stability of the nonlinear discrete-time system for trajectory tracking control is discussed. A soft robotic exoskeleton digit (exo-digit) and a 3D-printed human-finger model integrated with IMU sensors were used for the experimental test setup. An Arduino-based electro-pneumatic control hardware was developed to control the actuation pressure of the soft exo-digit. The effectiveness of the controller was examined through simulation studies and experimental testing for following different pose trajectories corresponding to the human finger pose during the activities of daily living. The model-based controller was able to follow the desired trajectories with a very low average root-mean-square error of 2.27 mm in the x-direction, 2.75 mm in the y-direction, and 3.90 degrees in the orientation of the human finger distal link about the z-axis.
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Tang, Xianzhi, Jilong Lin, Kun Zhao, Longfei Shi, and Bo Wang. "Analysis of Optimal Oxygen Excess Ratio and Nonlinear Tracking Control of Vehicle PEMFC Air Supply System." Mathematical Problems in Engineering 2021 (November 8, 2021): 1–17. http://dx.doi.org/10.1155/2021/4914816.
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To a large extent, the efficiency and durability of the proton exchange membrane fuel cell (PEMFC) depend on the effective control of air supply system. However, dynamic load scenarios, internal and external disturbances, and the characteristics of strong nonlinearity make the control of complex air supply systems challenging. This paper mainly studies the modeling of PEMFC air supply system and the design of a nonlinear controller for oxygen excess ratio tracking control. First, we analyze and calibrate the system’s optimal oxygen excess ratio control target and explore how the system temperature and humidity impact it, respectively; second, a second-order affine oriented control model which can represent the static and dynamic characteristics of the air supply system is derived, and a disturbance observer is designed to estimate and compensate the “lumped error” online. Then, aiming at the problem of unmeasurable cathode pressure, a state observer based on Kalman optimal estimation algorithm is proposed to realize the real-time estimation of cathode pressure; finally, a dynamic output feedback control system based on observer and backstepping nonlinear controller is proposed, and the comparison and evaluation of two control strategies based on constant oxygen excess ratio tracking and optimal oxygen excess ratio tracking are carried out. The simulation results show the effectiveness and superiority of the designed control system compared with the reference controller.
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Tian, Mengmeng, Hailiang Cai, Wenliang Zhao, and Jie Ren. "Nonlinear Predictive Control of Interior Permanent Magnet Synchronous Machine with Extra Current Constraint." Energies 16, no. 2 (January 7, 2023): 716. http://dx.doi.org/10.3390/en16020716.
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The interior permanent magnet synchronous machine (IPMSM) has been widely used in industrial applications due to its several favorable advantages. To further improve the machine performance, an improved nonlinear predictive controller for the IPMSM is proposed. In this paper, the maximum torque per ampere control law is firstly transformed to a linear function, according to the first−order Taylor expansion, and integrated with the control strategy. On this basis, an improved predictive control method is formulated by designing an optimized cost function through the input−output feedback linearization. Then the integral action is introduced to eliminate the influence of the load mutation and improve the steady−state control precision of the system. The stability of the control method is ensured by compelling the outputs to track the desired references without steady−state error. Finally, the simulation was established to verify the effective of the improved control method. Simulation results showed that the machine can reach the given reference speed without steady−state error within a short process, which means the machine has excellent dynamic and static performances. Furthermore, the machine has higher torque−to−current ratio by making full use of the reluctance torque. The simulation results verify the effectiveness of the improved control strategy.
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Oveisi, Atta, and Tamara Nestorovic. "Mixed Kalman-Fuzzy Sliding Mode State Observer in Disturbance Rejection Control of a Vibrating Smart Structure." International Journal of Acoustics and Vibration 24, no. 4 (December 31, 2019): 677–86. http://dx.doi.org/10.20855/ijav.2019.24.41365.
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In the controllers that are synthesized on a nominal model of a nonlinear plant, the parametric matched uncertainties and nonlinear/unmodelled dynamics of the high order nature can significantly affect the performance of the closed-loop system. On this note, owing to the robust characteristic of the sliding mode observer against modelling perturbations, measurement noise, and unknown disturbances and due to the non-fragile behaviour of the Kalman filter against process noise, a mixed Kalman sliding mode state-observer is proposed and later enhanced by the addition of an intelligent fuzzy agent. In light of the proposed technique, the chattering phenomena and the conservative boundary neighboring layer of the high gain sliding mode observer are addressed. Then, a robust active disturbance rejection controller is developed by using the static feedback of the estimated states using a~direct Lyapunov quadratic stability theorem. The reduced order plant for control design purposes is subjected to some simulated square-integrable disturbances and is assumed to have mismatched uncertainties in the system matrices. Finally, the robust performance of the closed-loop scheme with respect to the mentioned perturbation signals and modelling imperfections is tested by implementing the control system on a mechanical vibrating smart cantilever beam.
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Yassin, Houssein, Tania Demonte Gonzalez, Gordon Parker, and David Wilson. "Effect of the Dynamic Froude–Krylov Force on Energy Extraction from a Point Absorber Wave Energy Converter with an Hourglass-Shaped Buoy." Applied Sciences 13, no. 7 (March 29, 2023): 4316. http://dx.doi.org/10.3390/app13074316.
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Point absorber wave energy converter (WEC) control strategies often require accurate models for maximum energy extraction. While linear models are suitable for small motions, the focus is on the nonlinear model of an hour-glass shaped buoy undergoing large vertical displacements. Closed-form expressions for the static and dynamic Froude–Krylov forces are developed. It is shown that, in general, the dynamic and static forces are of similar magnitude, which is not the case for a spherical buoy. While the dynamic force reduces the amplitude of the net buoy force, its shape predicts a larger buoy response than if neglected, causing the nonlinear terms to have an even more significant effect. An input-state feedback linearizing controller is developed to show how the nonlinear model can be used in a control law. A 2.5 m buoy example is simulated to illustrate the approach of tracking an arbitrary displacement reference. For the case considered, the extracted power is 30% larger when the nonlinear dynamic FK force is used in the control law. The hourglass buoy is also compared to a spherical buoy to illustrate differences in their response to regular waves and energy extraction when using the same control laws. A spherical buoy diameter of 7.5 m was required to obtain the same power output as a 5 m tall hourglass buoy. A power-force-amplitude (PFA) metric is introduced to compare energy extraction performance and power take-off requirements. The hourglass buoy’s PFA was 13% larger than the spherical buoy implying that it can produce similar power but with less control effort.
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Ye, Xiaorong, Junxiang Lian, Guoying Zhao, and Dexuan Zhang. "A Novel Closed-Loop Structure for Drag-Free Control Systems with ESKF and LQR." Sensors 23, no. 15 (July 28, 2023): 6766. http://dx.doi.org/10.3390/s23156766.
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Space-borne gravitational wave detection satellite confronts many uncertain perturbations, such as solar pressure, dilute atmospheric drag, etc. To realize an ultra-static and ultra-stable inertial benchmark achieved by a test-mass (TM) being free to move inside a spacecraft (S/C), the drag-free control system of S/C requires super high steady-state accuracies and dynamic performances. The Active Disturbance Rejection Control (ADRC) technique has a certain capability in solving problems with common perturbations, while there is still room for optimization in dealing with the complicated drag-free control problem. When faced with complex noises, the steady-state accuracy of the traditional control method is not good enough and the convergence speed of regulating process is not fast enough. In this paper, the optimized Active Disturbance Rejection Control technique is applied. With the extended state Kalman filter (ESKF) estimating the states and disturbances in real time, a novel closed-loop control structure is designed by combining the linear quadratic regulator (LQR) and ESKF, which can satisfy the design targets competently. The comparative analysis and simulation results show that the LQR controller designed in this paper has a faster response and a higher accuracy compared with the traditional nonlinear state error feedback (NSEF), which uses a deformation of weighting components of classical PID. The new drag-free control structure proposed in the paper can be used in future gravitational wave detection satellites.
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Su, Liang, Zhenpo Wang, and Chao Chen. "Torque vectoring control system for distributed drive electric bus under complicated driving conditions." Assembly Automation 42, no. 1 (October 13, 2021): 1–18. http://dx.doi.org/10.1108/aa-12-2020-0194.
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Purpose The purpose of this study is to propose a torque vectoring control system for improving the handling stability of distributed drive electric buses under complicated driving conditions. Energy crisis and environment pollution are two key pressing issues faced by mankind. Pure electric buses are recognized as the effective method to solve the problems. Distributed drive electric buses (DDEBs) as an emerging mode of pure electric buses are attracting intense research interests around the world. Compared with the central driven electric buses, DDEB is able to control the driving and braking torque of each wheel individually and accurately to significantly enhance the handling stability. Therefore, the torque vectoring control (TVC) system is proposed to allocate the driving torque among four wheels reasonably to improve the handling stability of DDEBs. Design/methodology/approach The proposed TVC system is designed based on hierarchical control. The upper layer is direct yaw moment controller based on feedforward and feedback control. The feedforward control algorithm is designed to calculate the desired steady-state yaw moment based on the steering wheel angle and the longitudinal velocity. The feedback control is anti-windup sliding mode control algorithm, which takes the errors between actual and reference yaw rate as the control variables. The lower layer is torque allocation controller, including economical torque allocation control algorithm and optimal torque allocation control algorithm. Findings The steady static circular test has been carried out to demonstrate the effectiveness and control effort of the proposed TVC system. Compared with the field experiment results of tested bus with TVC system and without TVC system, the slip angle of tested bus with TVC system is much less than without TVC. And the actual yaw rate of tested bus with TVC system is able to track the reference yaw rate completely. The experiment results demonstrate that the TVC system has a remarkable performance in the real practice and improve the handling stability effectively. Originality/value In view of the large load transfer, the strong coupling characteristics of tire , the suspension and the steering system during coach corning, the vehicle reference steering characteristics is defined considering vehicle nonlinear characteristics and the feedforward term of torque vectoring control at different steering angles and speeds is designed. Meanwhile, in order to improve the robustness of controller, an anti-integral saturation sliding mode variable structure control algorithm is proposed as the feedback term of torque vectoring control.
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Labutin, A. N., Yu N. Zagarinskaya, V. Yu Nevinitsyn, G. V. Volkova, and V. A. Zaitsev. "Synthesis and modeling of the multidimensional technological object control system on the state regulator basis." Vestnik IGEU, no. 2 (2020): 57–64. http://dx.doi.org/10.17588/2072-2672.2020.2.057-064.
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The problem of structural-parametric synthesis of automatic control systems (ACS) of technological objects is deter-mined by the multi-dimensionality, multi-connectedness and nonlinearity of their mathematical models. Despite the indicated properties of such objects, traditional linear systems based on PID-algorithms are still used for process control. Since the synthesis of linear systems using input-output models does not take into account the multi-dimensionality and mutual influence of state coordinates, such systems increase the influence of parametric and signal perturbations on the quality of control processes. The increasing requirements for the quality and efficiency of technological processes control made it expedient to apply the control principle by the state vector based on the use of uninertial state regulators or combined state regulators including flexible feedback on the derivative state coordinates or state coordinate integrals. The research uses methods of system analysis of technological processes as control objects, methods of automatic control theory, methods of control systems synthesis on the state regulators basis, meth-ods of computer simulation. The linearized mathematical model of liquid-phase chemical reactor in the state space has been obtained. It has been established that the investigated object has the property of free movement stability and it is fully controlled in the state space. The problem of synthesis of a single-channel concentration vector control system in a chemical reactor using state regulator has been solved. The parameters of state regulator settings have been determined using the method of modal control. The efficiency of the automatic control system on the basis of the state regulator with an integral component has been shown using the method of computer simulation of the ‘nonlinear object – linear control subsystem’ complex. It has been demonstrated that the absence of an integral component in the control algorithm structure leads to a great static error of regulation. To eliminate the static error of control and ensure the robustness of the control system, it is recommended to introduce an integral component into the structure of state controller. This ensures the efficiency of the control system both for the case of complete measurement of the state vector and for the case of measurement of the output controlled variable only.
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Kamaludin, Khairun Najmi, Lokman Abdullah, Syed Najib Syed Salim, Zamberi Jamaludin, Nur Aidawaty Rafan, Mohd Fua'ad Rahmat, and Rprakash Ramanathan. "TRIPLE NONLINEAR HYPERBOLIC PID WITH STATIC FRICTION COMPENSATION FOR PRECISE POSITIONING OF A SERVO PNEUMATIC ACTUATOR." IIUM Engineering Journal 24, no. 2 (July 4, 2023): 315–36. http://dx.doi.org/10.31436/iiumej.v24i2.2766.
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Accurate and precise positioning control is critical in designing a positioning servo pneumatic system. The internal friction force of the pneumatic is one of the disturbances that make it challenging to achieve accurate and precise positioning. Dynamic friction identification and modelling are usually very complex and computationally exhaustive. In addition, pneumatic actuators are nonlinear systems, and applying linear control to the system is a mismatch. This study proposes an enhanced triple nonlinear hyperbolic PID controller with static friction (T-NPID+FSS) feedback module. T-NPID is integrated with nonlinear hyperbolic functions at each PID gain, hence the name. The reference in designing the T-NPID is the Popov stability criterion. Meanwhile, static friction (comparatively more straightforward than dynamic friction) is identified by measuring the actuator's internal friction at various velocities and applying it to the static friction model. T-NPID+FSS is compared to a classical PID, a PID with static friction (PID+FSS), and T-NPID without the friction module. With the comparisons, the performance gains of each module are clear. While most previous research focuses on the sinusoidal wave tracking performance (measuring the maximum tracking error, MTE, and root mean square error, RMSE), the analysis in this research focuses on obtaining precise positioning; steady-state analysis is the primary measurement. However, transient response and integral of absolute error (IAE) analysis are also observed to ensure no significant drawback in the controller's performance. T-NPID+FSS achieved the best precise positioning control, with 88.46% improvement over PID, 71.15% over PID+FSS, and 59.46% over T-NPID. The final controller is also on par with T-NPID for transient responses compared to the base PID. Although the FSS model caters to friction compensation, optimizing the FSS parameter by applying artificial intelligence, such as Neural Networks (NN) and Genetic Algorithm (GA), will increase the friction modeling‘s accuracy, and improve the compensation. ABSTRAK: Kawalan kedudukan yang tepat dan jitu adalah kitikal dalam mereka bentuk sistem pneumatik servo penentududukan. Daya geseran dalaman pneumatik adalah salah satu gangguan yang menyukarkan untuk mencapai kedudukan yang tepat dan jitu. Penentuan daya geseran dinamik dan pemodelannya selalunya kompleks dan pengiraan menyeluruh yang sukar. Selain itu, pneumatik ialah sistem tak linear, menggunakan kawalan linear pada sistem adalah tidak padan. Kajian ini mencadangkan PID hiperbolik tiga fungsi tak linear yang dipertingkatkan dengan modul suapan-balik geseran statik (T-NPID+FSS). T-NPID diintegrasikan dengan tiga fungsi hiperbolik tidak linear pada setiap pendarab PID, member pada nama. T-NPID direka bentuk dengan kriteria kestabilan Popov. Manakala geseran statik (secara perbandingan lebih mudah daripada geseran dinamik) dikenal pasti dengan mengukur geseran dalaman penggerak pada pelbagai halaju dan menerapkannya pada model geseran statik. T-NPID+FSS dibandingkan dengan PID klasik, PID dengan geseran statik (PID+ FSS) dan T-NPID tanpa modul geseran. Dengan perbandingan, prestasi peningkatan setiap modul adalah jelas. Walaupun kebanyakan penyelidikan terdahulu memfokuskan pada prestasi penjejakan gelombang sinusoidal (mengukur ralat penjejakan maksimum, MTE dan ralat purata kuasa dua akar, RMSE), analisis kajian ini memberi tumpuan kepada mendapatkan kedudukan yang tepat; oleh itu, analisis keadaan akhir ialah ukuran utama. Walau bagaimanapun, tindak balas sementara dan analisis kamiran ralat mutlak (IAE) juga diperhatikan untuk memastikan tiada kelemahan ketara dalam prestasi pengawal. T-NPID+FSS mencapai kawalan penentududukan tepat terbaik, dengan peningkatan 88.46% berbanding PID, 71.15% berbanding PID+FSS dan 59.26% berbanding T-NPID. Pengawal yang dicadangkan juga setanding dengan T-NPID untuk respons sementara berbanding PID asas. Walaupun model FSS telah ditunjukkan untuk memenuhi pampasan geseran, mengoptimumkan parameter FSS dengan menggunakan kecerdasan buatan (artificial intelligence, AI) seperti Neural Networks, NN dan Genetic Algorithms, GA akan meningkatkan ketepatan dan pampasan pemodelan geseran.
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Gehan, O., E. Pigeon, T. Menard, M. Pouliquen, H. Gualous, Y. Slamani, and B. Tala-Ighil. "A Nonlinear State Feedback for DC/DC Boost Converters." Journal of Dynamic Systems, Measurement, and Control 139, no. 1 (October 17, 2016). http://dx.doi.org/10.1115/1.4034602.
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This paper investigates the control problem for static boost type converters using a high gain state feedback robust controller incorporating an integral action. The robust feature allows to achieve the required performance in the presence of parametric uncertainties, while the integral action provides an offset free performance with respect to the desired levels of voltage. The adopted high gain approach is motivated by both fundamental as well as practical considerations, namely the underlying fundamental potential and the design parameter specification simplicity. The stability and convergence analysis has been carried out using an adequate Lyapunov approach, and the control system calibration is achieved throughout a few design parameters which are closely related to the desired dynamical performances. The effectiveness of the proposed control approach has been corroborated by numerical simulations and probing experimental results.
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Petrov, Plamen, and Ivan Kralov. "Modelling and Feedback Control for Reversing a Nonholonomic Mobile Robot Platoon." Proceedings of the Bulgarian Academy of Sciences 76, no. 9 (October 1, 2023). http://dx.doi.org/10.7546/crabs.2023.09.11.
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This paper addresses the control problem of a platoon of nonholonomic mobile robots in the case of backward motion of the leading robot. By using a virtual non-static with respect to the lead robot reference frame as a target, a kinematic model of the robot platoon in error coordinates is developed. A nonlinear feedback controller based on the entire platoon model is designed by means of high-gain control. Asymptotic stability property of the closed-loop system is established using Lyapunov theory. For backward motion of the leading robot along a circular path, at steady-state, the two-robot platoon should travel concentric arcs of same radii with prescribed inter-robot spacing. The performance of the proposed tracking controller is illustrated through numerical simulations.
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Azarang, A., M. Miri, S. Kamaei, and M. H. Asemani. "Nonfragile Fuzzy Output Feedback Synchronization of a New Chaotic System: Design and Implementation." Journal of Computational and Nonlinear Dynamics 13, no. 1 (October 9, 2017). http://dx.doi.org/10.1115/1.4037416.
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A new three-dimensional (3D) chaotic system is proposed with four nonlinear terms which include two quadratic terms. To analyze the dynamical properties of the new system, mathematical tools such as Lyapunov exponents (LEs), Kaplan–York dimensions, observability constants, and bifurcation diagram have been exploited. The results of these calculations verify the specific features of the new system and further determine the effect of different system parameters on its dynamics. The proposed system has been experimentally implemented as an analog circuit which practically confirms its predicted chaotic behavior. Moreover, the problem of master–slave synchronization of the proposed chaotic system is considered. To solve this problem, we propose a new method for designing a nonfragile Takagi–Sugeno (T–S) fuzzy static output feedback synchronizing controller for a general chaotic T–S system and applied the method to the proposed system. Some practical advantages are achieved employing the new nonlinear controller as well as using system output data instead of the full-state data and considering gain variations because of the uncertainty in values of practical components used in implementation the controller. Then, the designed controller has been realized using analog devices to synchronize two circuits with the proposed chaotic dynamics. Experimental results show that the proposed nonfragile controller successfully synchronizes the chaotic circuits even with inexact analog devices.
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RAHBARALAM, ELAHEH, YOUSEF BAZARGAN LARI, HAMED AGAHI, and KIMIA BAZARGAN LARI. "TUMOR VOLUME GROWTH CONTROL USING BIFURCATION APPROACH." Journal of Mechanics in Medicine and Biology, June 18, 2022. http://dx.doi.org/10.1142/s0219519422500282.
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A tumor growth system with immune response and chemotherapy is put in a nonlinear dynamical system whose solutions are relative to the initial data. This study presents a phase space analysis of the system. Here, the basin of equilibrium points attraction is determined for a particular class of systems and is subjected to input and state constraints in which all points in phase space would be close to the equilibrium points according to the region of attraction it starts. The addition of a drug term to the system can move the solution trajectory to the desirable basin of attraction. The proposed method gives static output feedback controllers that guarantee the convergence of the generic solutions. Although such a set-point regulation problem is too challenging for general nonlinear systems, the standard surface is found by the proposed approach, which is called separatrix for the controller. This criterion of separating border can perform well even when the mentioned system has limited change parameters. The control is set by separatrix in which the output feedback controller therapy can take all solutions to the healthy state through a constrained chemotherapy protocol. Moreover, this protocol can enable globalization of healthy equilibria.
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Medjebouri, Ali. "Extended State Observer Based Robust Feedback Linearization Control Applied to an Industrial CSTR." Journal of Automation, Mobile Robotics and Intelligent Systems, March 7, 2024, 68–78. http://dx.doi.org/10.14313/jamris/4-2023/32.
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In the chemical and petrochemical industries, the Continuous Stirred Tank Reactor (CSTR) is, without doubt, one of the most popular processes. From a control point of view, the mathematical model describing the temporal evolution of the CSTR has a strongly nonlinear cross-coupled character. Moreover, modeling errors such as external disturbances, neglected dynamics, and parameter variations or uncertainties make its control task a very difficult challenge. This problem has been the subject of a wide number of control strategies. This article attempts to propose a viable, robust nonlinear decoupling control scheme. The idea behind the proposed approach lies in the design of two nested control loops. The inner loop is responsible for the compensation of the nominal model's nonlinear cross-coupled terms via a static nonlinear feedback; while the outer loop, designed around an Extended State Observer (ESO), which the additional state gathers the global effect of modeling errors, is charged with instantaneously estimating and then compensating the ESO extended state. This way, the CSTR complex dynamics are reduced to a series of decoupled linear subsystems easily controllable using a simple Proportional-Integral (PI) linear control to ensure the robust pursuit of reference signals respecting the desired performance. The presented control validation was performed numerically by an objective comparison to a classical PID controller.
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Li, Wenzi, Baowei Wu, Yue-E. Wang, and Lili Liu. "Static output feedback H∞ control for switched LPV time-delay systems with nonlinear constraints." Transactions of the Institute of Measurement and Control, October 12, 2022, 014233122211243. http://dx.doi.org/10.1177/01423312221124364.
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This paper addresses the issues of static output feedback [Formula: see text] control for switched linear parameter-varying (LPV) time-delay systems using multiple parameter-dependent Lyapunov functions. First, a parameter and state-dependent switching strategy with dwell time is designed and a sufficient condition ensuring the stability of the unforced switched LPV time-delay systems is established with the aid of the switching law. Then, the piecewise parameter-dependent controller is designed, such that the closed-loop system is asymptotically stable and satisfies an [Formula: see text] performance index. Finally, two examples are provided to show the effectiveness of the results.
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Cole, M. O. T., C. Chamroon, and P. Ngamprapasom. "Force Feedback Control for Active Stabilization of Synchronous Whirl Orbits in Rotor Systems With Nonlinear Stiffness Elements." Journal of Vibration and Acoustics 134, no. 2 (January 26, 2012). http://dx.doi.org/10.1115/1.4005021.
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Synchronous vibration in rotor systems having bearings, seals, or other elements with nonlinear stiffness characteristics is prone to amplitude jump when operating close to critical speeds as there may be two or more possible whirl motions for a given unbalance condition. This paper describes research on how active control techniques may eliminate this potentially undesirable behavior. A control scheme based on feedback of rotor-stator interaction forces is considered. Model-based conditions for stability of low amplitude whirl, derived using Lyapunov’s direct method, are used to synthesize controller gains. Subsidiary requirements for existence of a static feedback control law that can achieve stabilization are also explained. An experimental validation is undertaken on a flexible rotor test rig where nonlinear rotor-stator contact interaction can occur across a small radial clearance in one transverse plane. A single radial active magnetic bearing is used to apply control forces in a separate transverse plane. The experiments confirm the conditions under which static feedback of the measured interaction force can prevent degenerate whirl responses such that a low amplitude contact-free orbit is the only possible steady-state response. The gain synthesis method leads to controllers that are physically realizable and can eliminate amplitude jump over a range of running speeds.
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AK, Rusdhianto Effendie, Muhamad Rafif Prasetyo, and Zulkifli Hidayat. "Designing an Optimal Control LQT for Controlling and Guidance of Missile." JAREE (Journal on Advanced Research in Electrical Engineering) 2, no. 1 (May 31, 2018). http://dx.doi.org/10.12962/j25796216.v2.i1.36.
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Missile has to be controlled and follow the commanded guidance in order to make its flight hit the target. Since missile has a nonlinear characteristic and coupled dynamic equation, controlling a missile has become more complex. Linear Quadratic Tracking (LQT) is one of optimal control theory where its objective is to make the output of a system tracks its reference as close as possible while minimize or maximize a desired performance index. In this paper, an autopilot for missile is designed which consists nonlinear state feedback decoupler and LQT controller. Pursuit Guidance is used for the guidance law. A missile-target engagement simulation is created using 2 kinds of target; static target and dynamic target. By using static target, the mean of the closest distance between missile and the target is 0.45 meters and by using dynamic target the mean of the closest distance between missile and the target is 2.562 meters.
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Ding, Jingang, and Xiaohong Jiao. "Observer-based adaptive dynamic sliding mode control for automatic clutch position tracking." Proceedings of the Institution of Mechanical Engineers, Part E: Journal of Process Mechanical Engineering, October 30, 2023. http://dx.doi.org/10.1177/09544089231209201.
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The automatic clutch’s precise and stable position tracking is critical in automated manual transmission, significantly influencing vehicle performance. Clutch position control is challenging due to directly unmeasurable clutch output position, nonlinear characteristics, parameter uncertainties, and external disturbance of the automatic clutch system. This paper proposes an observer-based adaptive dynamic sliding mode control strategy to overcome these obstacles to the clutch position tracking process. The extended state observer (ESO) introduced in the designed strategy handles total disturbance, including nonlinearities and uncertainties for feedback control and total compensation. A sigmoid tracking differentiator arranges the transient process and smooth approach signal for the reference input and its differential signal. An adaptive dynamic sliding mode controller acts as the primary feedback control to realize fast and precise position tracking of the automatic clutch system based on the signal from ESO. Simulation and hardware-in-loop (HIL) experimental tests verify the effectiveness and advantage of the proposed control strategy for the clutch position tracking performance in the face of parameter perturbation and external disturbance, for example, the root mean square value of static tracking error of the designed strategy is 14.9% and 24.7% lower than that of ESO-based sliding mode control and robust sliding mode control strategy in the HIL test, respectively.