The design of switching functions is extremely important in the design of sliding mode controllers in that it closely relates to the solvability of the sliding mode control problems. This paper is ...concerned with the design problems of switching functions and fuzzy sliding mode controllers for T-S fuzzy descriptor systems. First, a generalized regular form of T-S fuzzy descriptor systems is defined. Then the design method of the linear switching function-based fuzzy sliding mode controller is developed and the result obtained indicates a relationship between the design parameter in the switching function and the gain matrix in the controller of T-S fuzzy systems. From this relationship, a new framework of the switching function design for T-S fuzzy descriptor systems is formulated. Moreover, the design method of the fuzzy switching function-based sliding mode controllers is proposed to exemplify the proposed framework. It is shown that the proposed fuzzy switching function-based method is less conservative than the linear switching function-based method from the viewpoint of the solvability of the sliding mode control problems. Finally, the results obtained are verified through four illustrative examples.
In this paper, a continuous control strategy for robust stabilization of a class of uncertain multivariable linear systems with delays in both the state and control variables is proposed. A predictor ...is designed to compensate the delay effect in the control input, and then an integral sliding mode control technique along with super-twisting algorithm is applied to compensate partially the effect of the perturbation term. Finally, a nominal delay-free part of the control input is designed to stabilize the sliding mode dynamics. The proposed control scheme is extended to the class of systems modeled in Regular form. For this class of perturbed systems with delay in the state, a transformation to the systems with the delay-free state is proposed. The stability conditions of the closed-loop uncertain system are derived, and the results obtained in this work are compared against previous works. To show the effectiveness of the proposed method, simulation results are presented.
This paper presents a fixed-time neuro-adaptive control design for a class of uncertain under-actuated nonlinear systems (UNS) using a non-singular fast terminal sliding mode control (TSMC) with a ...radial basis function (RBF)-based estimator to achieve the convergence and robustness against the uncertainties. The mathematical model of the considered class is reduced into an equivalent regular form. A fast TSMC is designed for the transformed form to improve the control performance and annihilate the associated singularity problem of the conventional TSMC. Lyapunov stability theory ensures the steering of the sliding manifold and system states in fixed time. RBF neural networks are adaptively estimate the nonlinear drift functions. The theoretical design, analysis, and simulations of cart-pendulum and quadcopter demonstrate the feasibility and benefits of the regular form transformation and the designed control design. Comparing the proposed synthesis with the standard literature presents the attractive nature of proposed method for such a class.
This paper investigates a linear sliding variable-based decentralized static output feedback sliding mode controller design problem of interconnected descriptor systems. A generalized regular form ...for interconnected descriptor systems is introduced. Based on the generalized regular form, a linear matrix inequality-based method is given to solve the designing matrix in the linear sliding variable and a decentralized static output feedback sliding mode controller is synthesized to stabilize the interconnected descriptor systems. It is shown that the proposed static output feedback sliding mode control method can still stabilize the interconnected descriptor systems even when unknown matched disturbances exist. Finally, a simulation result on the hypersonic vehicle system is given to illustrate the validity of the proposed method.
Here we consider a certain transfert operator \(\mathrm{M}_{(c,\omega)}=I_{\mathcal{P}}-c \, \tau_{\omega},\) \(\omega\neq0,\) \({c \in \mathbb{R}-\{0,1\},}\) and we prove the following statement: up ...to an affine transformation, the only orthogonal sequence that remains orthogonal after application of this transfert operator is the Meixner polynomials of the first kind.
This paper deals with the design of active fault-tolerant control (FTC) system based on control allocation (CA) technique for the uncertain descriptor system (DS) with actuator saturation. This work ...assumes that a fault detection unit is available to estimate the actuator fault. The proposed CA technique is responsible to redistribute the control effort to the healthy actuators taking the advantage of actuator redundancy of the DS. The so-called virtual control law is designed based on a variable gain super twisting sliding mode algorithm (VGSTSMA) to meet the admissibility criteria of continuous control input for the DS. This VGSTSMA based control strategy is designed based on the generalized regular form (GRF) of DS ensuring the robustness against the actuator faults, error in the fault estimation, and the external uncertainties. The CA scheme developed here is applicable to the DS even with a full rank input matrix which is different from the traditional design where it generally deals with the system with rank deficient input matrix. Furthermore, a static control redistribution mechanism is introduced to handle the actuator saturation which is responsible to re-allocate the excess control efforts to the available healthy actuators in the face of actuator saturation. Finally, a dual-pipe heat exchanger unit, modeled as DS, is simulated with proposed CA-based FTC such that the system can follow the time varying and constant reference trajectories in a situation of actuator faults and saturation. The simulation results are compared with the CA-based FTC where virtual control is designed based on super-twisting algorithm (STA) and with the traditional pseudo inverse-CA-based FTC to establish the superiority of the proposed scheme.
•A CA-based FTC strategy for the uncertain DS with a full rank input matrix has been proposed.•A robust VGSTA based SMC has been proposed for the DS to design the virtual controller as a CA strategy.•A static redistribution mechanism is introduced with CA-based FTC in order to handle the actuator saturation limits in the system.•The proposed CA-based FTC strategy has been simulated for a dual heat exchanger unit modeled as DS.
In this paper, a generalized regular form is proposed to facilitate sliding mode control (SMC) design for a class of nonlinear systems. A novel nonlinear sliding surface is designed using implicit ...function theory such that the resulting sliding motion is globally asymptotically stable. Sliding mode controllers are proposed to drive the system to the sliding surface and maintain a sliding motion thereafter. Tracking control of a two-wheeled mobile robot is considered to underpin the developed theoretical results. Model-based tracking control of a wheeled mobile robot is first transferred to a stabilization problem for the corresponding tracking error system, and then the developed theoretical results are applied to show that the tracking error system is globally asymptotically stable even in the presence of matched and mismatched uncertainties. Both experimental and simulation results demonstrate that the developed results are practicable and effective.
This study investigates the design problem of the linear sliding variable-based sliding mode controllers of descriptor systems via output information. A generalised regular form, which is the ...counterpart of that for normal systems, is first recalled. Then a static output feedback sliding mode control strategy is developed to stabilise the descriptor system under consideration and the result is further improved by a reduced-order observer-based sliding mode control strategy. Necessary and sufficient conditions are derived such that the resulting sliding motion is regular and asymptotically stable. It is shown that the main merit of the static output feedback sliding mode control method is the simplicity and that of the reduced-order observer-based sliding mode control method is the elimination of a restrictive assumption frequently used in the static output feedback sliding mode control method. Finally, two connected one-mass oscillators model is numerically simulated to testify the validity of the proposed methods.
Urban landscape parks play a crucial role in providing recreational opportunities for citizens. Different types of landscapes offer varying levels of comfort experiences. However, the assessment of ...landscape comfort primarily relies on subjective evaluations and basic physiological measurements, which lack sufficient quantification of relevant data. This study employed electroencephalography (EEG) technology and subjective questionnaire evaluation methods. Participants observed two sets of landscape demonstration videos using virtual reality (VR) devices, and EEG alpha values and subjective evaluation scores were collected to assess the comfort levels of free-form landscape and regular-form landscape. Additionally, this study explored the correlation between landscape characteristics and physiological comfort. The analysis of the results showed that: 1. The average amplitude of EEG alpha waves recorded from 11 electrodes in the left temporal lobe and right parietal lobe of the participants was higher after they watched the free-form landscape demonstration. The increased alpha values suggest that free-form landscapes are more likely to induce physiological comfort in these specific brain regions. In contrast, regular-form landscape was found to induce higher alpha values at seven specific electrodes located in the occipital cortex, right temporal lobe, and central regions of the participants. In general, free-form landscape provided physiological comfort to a greater number of brain regions. 2. The two groups of landscapes exhibit distinct subjective cognitive differences in terms of their landscape characteristics. These differences, ranked in order of magnitude, include rhythmicity, sense of order, sense of security, and sense of dependence. 3. This study examined the α-waves of specific brain regions, including the right and left temporal lobe and occipital lobe, as well as subjective scoring. It discovered that the rhythmicity, degree of variation, degree of color, and sense of nature of a landscape impact the α-wave value of electrodes in different brain regions. Moreover, there exists a certain linear relationship between the four landscape features and the α-wave values in different regions of the brain. The results of this study provide some reference for the creation of a comfortable landscape design.
The Special Issue aimed to bring together scientists working in various branches of control theory to discuss manufacturing control problems that include the following: enterprise control and digital ...ecosystem creation; the development of identification theory and methodology, and related mathematical problems; parameter, nonparametric, and structure identification and expert analysis; problems regarding selection and data analysis; control systems with an identifier; modeling in intelligent systems; simulation procedures and software; digital identification; reinforcement learning; quantum modeling; intelligent model predictive control; predictive cognitive issues; problems with software quality for complex systems; and global network resources for support processes of modeling and control.
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