Disturbance Attenuation Performance Research Articles

Observer-based quantized control for networked interconnected PDE systems with actuator failures

This paper proposes an observer-based quantized controller for parabolic partial differential equation systems interconnected by a nonlinear coupling protocol. First, a Markov jump model is introduced to describe various randomly occurring actuator failures, and an observer-based pointwise controller is designed under the averaged measurement scheme. Furthermore, taking into account the limitation of network communication resources, a quantization method is adopted to relieve bandwidth pressure. In addition, stability conditions of the closed-loop system with ℋ∞ disturbance attenuation performance are derived by utilizing appropriate Lyapunov functional and inequality techniques. Ultimately, the proposed method is applied to the Fisher equation to verify its feasibility and effectiveness.

Hidden Markov model‐based filtering for 2‐D Markov jump Roesser systems subject to analog fading channels

AbstractThis article considers the filtering problem for 2‐D Markov jump Roesser systems, in which the measurement signal is transmitted via analog fading channels. The time‐varying amplitude attenuation of the analog fading channels is described by the fading gain modeled as a random variable. The hidden Markov model is used to deal with the mode mismatch phenomenon between the plant and the filter, then a full‐order asynchronous filter is designed for 2‐D Markov jump Roesser systems under analog fading channels. The purpose is to introduce a filter to guarantee that the filtering error system is not only asymptotically mean square stable, but also satisfies the disturbance attenuation performance. An improved decoupling method is proposed to acquire the 2‐D filter parameters such that the conservatism of the 2‐D filter designed law can be effectively reduced. Finally, a verification example and Darboux equation are given to illustrate the validity of the introduced asynchronous filter design law.

Dynamic event‐triggered control of 2‐D continuous systems in Roesser model

AbstractIn this paper, a dynamic event‐triggered control problem is discussed for 2‐D continuous systems by the Roesser model. In order to reduce communication frequency and avoid dependence on global information, a dynamic event‐triggered mechanism is constructed, which is more flexible than some existing event‐triggered schemes with fixed event‐triggered thresholds. Utilizing the dynamic event‐triggered mechanism, a state feedback controller is designed. By constructing a 2‐D Lyapunov function, sufficient conditions expressed in terms of linear matrix inequalities (LMIs) are firstly established such that the 2‐D system is asymptotically stable with a disturbance attenuation performance. It is also proved that the Zeno phenomenon is excluded. Finally, two examples are provided to illustrate the effectiveness of the proposed method.

[formula omitted] filtering for uncertain discrete-time singular switched positive systems with time delay and output quantization

This paper focuses on the design problem of an l1 filter for singular switched positive systems with time delay and uncertainty. In order to enhance resource efficiency and information transmission security, the quantization mechanism is introduced when designing the filter. Furthermore, sufficient conditions for causality, regularity, positivity, and exponential stability of the filtering error system are provided under the constraint of mode-dependent minimum dwell time (MDMDT). These conditions are obtained by selecting an appropriate co-positive Lyapunov function and are presented in the form of linear programming (LP). Subsequently, the disturbance attenuation performance is further analyzed, and a design methodology for the corresponding filter is outlined. Finally, a numerical example is presented to verify the validity of the theoretical results.

Precision Landing of Unmanned Aerial Vehicle under Wind Disturbance Using Derivative Sliding Mode Nonlinear Disturbance Observer-Based Control Method

Unmanned aerial vehicles (UAVs) are extensively employed in civilian and military applications because of their excellent maneuverability. Achieving fully autonomous quadrotor flight and precision landing on a wireless charging station in the presence of wind disturbance has become a crucial research topic. This paper presents a composite control technique for UAV altitude and attitude tracking in harsh environments, i.e., wind disturbance. A composite controller was developed based on nonlinear disturbance observer (NDOB) control theory to allow the UAV to land in the presence of random external wind disturbances and ground effects. The NDOB estimated the unknown wind disturbance, and the estimation was fed into the derivative sliding mode nonlinear disturbance observer-based control (DSMNDOBC), allowing the UAV to perform autonomous precision landing. Two loop designs were applied: the inner loop for stabilization and the outer loop for altitude tracking. The quadrotor model dynamics and the proposed controller, DSMNDOBC, were simulated employing MATLAB/Simulink®, and the results were compared with the one obtained by the proportional derivative (PD) controller and the sliding mode controller (SMC). The simulation results indicated that the DSMNDOBC has superior altitude and attitude control compared to the PD and SMC controllers and better disturbance estimation and attenuation performance.

Sliding-mode-based impulsive control for a class of time-delay systems with input disturbance

This paper addresses the impulsive stabilization problem for a class of time-delay systems in the presence of input disturbances. A novel impulsive control law is constructed, which is based on the discrete-time equivalent control design technique. The sliding-mode-based impulsive control law allows counteracting the disturbance effect using its previous step value. To adapt in real time to the variation in sampling periods, the sliding function is designed as a function of impulse interval. Piecewise Lyapunov functions based on the partition on the maximum impulse interval are introduced to deal with the time-varying structure of the sliding function. Sufficient conditions for exponential input-to-state stability (EISS) of the impulsively controlled systems are derived, in which the EISS gain characterizes the attenuation ability of the proposed impulsive control law on the disturbance estimation error. The disturbance attenuation performance of the proposed impulsive control strategy is demonstrated through the time-delay Chua’s circuit.

L2$$ {L}_2 $$‐gain analysis and fault‐tolerant control for nonlinear discrete‐time switched systems with time‐varying delay and actuator saturation

AbstractThe ‐gain analysis and fault‐tolerant control of a class of uncertain nonlinear discrete‐time switched systems with time‐varying delay and actuator saturation are studied by using the multiple Lyapunov functions method. The fault‐tolerant state feedback controllers and the switching law are designed such that the closed‐loop system with actuator failures satisfies the disturbance attenuation performance indicator. The problem of estimating the capacity of admissible disturbance is transformed into a constrained optimization problem to ensure that the state trajectory of the closed‐loop system is bounded under the action of external disturbances. The upper bound of restricted ‐gain is estimated by solving constrained optimization problems. Then, when the fault‐tolerant controller can be regard as the design variable, the optimization problems above are adjusted for solving control synthesis problems. Finally, the numerical example is given to verify the effectiveness of the design method.

Nonfragile output-feedback control for switched singular positive systems with time-varying delay under the Round-Robin protocol

This paper investigates a class of switched singular positive systems with time-varying delay, where the system parameters are uncertain. In order to decrease the consumption of the communication resources and avoid the phenomenon of data congestion, Round-Robin protocol is employed here. This is the first few attempts to introduce the Round-Robin protocol for such kind of positive systems. Moreover, the nonfragile controller is designed to suppress the undesired dynamical behaviors, which may occur if no control is implemented. By means of the matrix decomposition technique and the mode-dependent average dwell time method, sufficient conditions are established to ensure that the obtained closed-loop system has a prescribed l1 disturbance attenuation performance. Finally, three examples are presented to illustrate feasibility and effectiveness of the proposed control scheme.

A novel unbiased [formula omitted] filter design for 2-D Markov jump systems in the Roesser model with general transition probabilities

The paper delves into the intricate details of unbiased H∞ filtering for 2-D Markov jump systems with general transition probabilities in the light of the Roesser model. In order to allow the Markov jump systems to better model practical engineering applications, general transition probabilities are introduced. These probabilities are more flexible, encompassing all unknown, all known, and partially unknown cases to improve their practical applicability. The goal of this study is to showcase a novel unbiased filter to make the filtering error system mean-square asymptotically stable and meet a specified H∞ disturbance attenuation performance. By constructing the Lyapunov function, sufficient condition for the corresponding filter to exist and the solutions of its parameters are given through linear matrix inequalities. Eventually, the Darboux equation is used to prove the utility of the presented filter.

A PARAMETER ADJUSTMENT LAW FOR MULTIVARIABLE PID CONTROL SYSTEMS WITH DISTURBANCE ATTENUATION PERFORMANCE

This paper shows a new parameter adjustment law of PID controllers for MIMO linear system with guaranteed disturbance attenuation performance. In the proposed design approach, the design problem of PID parameters is reduced to the problem of static output feedback controllers for MIMO linear systems. In this paper, we show that sufficient conditions for the existence of the proposed PID control system can be reduced to solvability of linear matrix inequalities (LMIs). Finally, a simple numerical example is shown to effectiveness of the proposed PID control system.

Observer-Based Security Fuzzy Control for Nonlinear Networked Systems Under Weighted Try-Once-Discard Protocol

This paper is concerned with the observer-based security fuzzy control problem for a class of nonlinear networked systems with imperfectly matched membership functions (MFs) under weighted try-once-discard (WTOD) protocol. The nonlinear networked system is constructed based on interval type-2 (IT2) Takagi-Sugeno (T-S) model, which can properly handle parameter uncertainties via lower and upper MFs. To mitigate the communication load, WTOD protocol is exploited to schedule the transmission order of the signals, in which those signals may be subjected to randomly occurring deception attacks. The observer is constructed under unmeasurable premise variables, and then the controller with imperfect matching MFs is designed according to the estimated states. Moreover, the observer-based controller is derived with Lyapunov stability theory such that the stochastic stability of the augmented closed-loop system with predefined disturbance attenuation performance can be guaranteed. Subsequently, sufficient conditions are provided for the desired observer and controller gain matrices based on linear matrix inequalities (LMIs) technique. Numerical simulation example demonstrates the validity of the proposed observer-based security fuzzy control design scheme.

A unified tuning rule of the simplified filtered Smith predictor for SISO and square MIMO high-order dead-time processes

This paper proposes a new unified tuning methodology for the simplified filtered Smith predictor for single-input single-output high-order processes with delay and square multi-input multi-output high-order processes with multiple delays. The strategy preserves the filtered Smith predictor properties for stable, unstable and integrative processes, and simplifies the controller tuning by proposing the state feedback decoupling for reference tracking and including the disturbance model on the controller design to deal with the trade-off between disturbance attenuation performance and robust stability condition. The simulation results illustrate the performance improvements when applying the proposed tuning compared to recently published cases. Furthermore, an experiment on a Neonatal Intensive Care Unity prototype effectively presents the general unified tuning methodology potential when applied to an industrial process with practical features.

An attitude cooperative control for multi‐spacecraft systems with arbitrary input delay time‐variation rate: A dynamic event‐triggered approach

SummaryA problem of the attitude cooperative control of multi‐spacecraft systems with input time‐varying delay under an undirected graph is addressed in this paper, where the delay does not require any assumption on the continuity of the delay and its time‐variation rate. Considering the communication bandwidth constraint and Zeno behavior, a dynamic event‐triggered scheme is presented, which is more general than some existing event‐triggered schemes with a fixed threshold. By Lyapunov function technology, sufficient conditions of bilinear matrix inequality (BMI) for the existence of controller gain are proposed firstly such that the closed‐loop system is attitude cooperative with a new disturbance attenuation performance. It is also proved that there is a lower bound between two adjacent triggers via the mathematical analytical method, that is, the Zeno phenomenon can be avoided. Finally, the efficacy of the proposed methods is verified via simulations.

Fault Detection and Reliable Controller Design for Fractional-Order Systems Based on Dynamic Observer

In this paper, the problem of the fractional-order linear systems’ simultaneous fault detection and reliable control (SFDC) in the finite frequency domain is investigated. A dynamic observer aimed at detecting faults is designed, which also generates state estimation signals. In particular, it is found that the proposed dynamic-observer-based controller can achieve a better H∞ performance. We derived the detector and controller’s design conditions to achieve H− fault sensitivity performance and H∞ interference attenuation performance in the limited frequency domain based on the generalized KYP lemma, which can achieve a better disturbance attenuation performance and fault sensitivity performance. Finally, the simulation results show the designed method’s effectiveness.

Disturbance Attenuation and Pointing Control System Design for an Improved Disturbance-Free Payload Spacecraft

The low-frequency disturbances transmitted by flexible cables are difficult to be attenuated for a novel disturbance-free payload spacecraft, which decreases the payload’s pointing accuracy and stability. In this research, a new spacecraft configuration with a high-precision inertial reference unit composed of capacitive sensors and a spherical test mass is proposed. The disturbance attenuation and pointing control system is subdivided into four interconnected control loops. The payload can be isolated from disturbances in the all-frequency band by the active vibration isolation control loop and the drag-free control loops, and its high-precision pointing requirement can be satisfied with the attitude pointing control loop and the attitude tracking control loop. An integrated control strategy is proposed, and the control system is decoupled into 12 single-input single-output control loops by pre-compensating, which lays the foundation for feedback design. Through the amplitude-frequency response analysis, the control bandwidth is designed according to the Proportional-Integral-Differentive control algorithm. The numerical simulations show that the disturbance attenuation performance is better than −20 dB in the all-frequency band, and the pointing accuracy and the pointing stability are better than 10−6 deg and 10−7 deg/s, respectively. The new spacecraft configuration and the disturbance attenuation and pointing control system provide a general technical solution for payloads with high-precision and high-stability requirements.

Designing an event-triggered [formula omitted] filter with possibly inconsistent modes for Markov jump systems

The design of event-triggered H∞ filters for Markov jump systems is studied. The transition rates of the Markov chain allow for being uncertain and even totally unknown. Meanwhile, the plant considered and its filter are allowed to have possibly inconsistent modes, resulting in a hidden Markov model (HMM). A dual-threshold periodic event-triggered scheme is introduced to save network channel resources. Under the event-triggered scheme, a sufficient condition of mean-square exponential stability and H∞ disturbance-attenuation performance is proposed for the HMM-based filtering error system. Then, a design approach for the desired event-triggered H∞ filter is developed by eliminating potential nonlinearities, without limiting the row sum of uncertain items in the transition rate matrix to zero. Finally, two examples, including a tunnel diode circuit, are provided to verify the effectiveness of the design approach.

Input-to-state stability of positive delayed neural networks via impulsive control

This paper is concerned with the positivity and impulsive stabilization of equilibrium points of delayed neural networks (DNNs) subject to bounded disturbances. With the aid of the continuous dependence theorem for impulsive delay differential equations, a relaxed positivity condition is derived, which allows the neuron interconnection matrix to be Metzler if the activation functions satisfy a certain condition. The notion of input-to-state stability (ISS) is introduced to characterize internal global stability and disturbance attenuation performance for impulsively controlled DNNs. The ISS property is analyzed by employing a time-dependent max-separable Lyapunov function which is able to capture the positivity characterization and hybrid structure of the considered DNNs. A ranged dwell-time-dependent ISS condition is obtained, which allows to design an impulsive control law via partial state variables. As a byproduct, an improved global exponential stability criterion for impulse-free positive DNNs is obtained. The applicability of the achieved results is illustrated through three numerical examples.

Consensus of linear network systems diffusively coupled with exogenous disturbances: An ℋ∞ approach

AbstractThis paper addresses the consensus control problem in multi‐agent systems under the influence of diffusively coupled disturbances. Two different types of systems are considered regarding the homogeneity of the disturbance coupling parameters. The main goal is to derive conditions that guarantee the prescribed performance of the designed control system on disturbance attenuation. To estimate the disturbance attenuation performance of the controller, the norm of the transfer function from the redefined disturbance vector to the disagreement vector is measured. Then the sufficient conditions for the system to achieve consensus within the desired performance are derived in terms of linear matrix inequalities (LMI). Numerical examples of both one‐ and multi‐dimensional consensus control systems are provided to check the validity of the derived LMI feasibility test along with the illustration of consensus behavior in time domain.

Sliding mode control for networked control systems under DoS attacks via an event-triggered scheme

This paper aims at proposing the sliding mode control method based on event-triggered scheme for networked control systems with periodic denial-of-service (DoS) attacks in the network environment. Firstly, considering the possible security problem in open communication networks, an event-triggered strategy ensuring the security of communication links under DoS attacks is designed, which can weaken the adverse impact of jamming signals in communication while providing benefits in improving resource utilization. Secondly, combined with the event-triggered control strategy, by aid of constructing the sliding surface function, the sliding mode dynamics is deduced, and the stability criterion with disturbance attenuation performance in H∞ sense is established by an improved inequality technique. On this basis, an control law is designed, which ensures the reachability of the sliding mode surface. Finally, the effectiveness of the control strategy is proved by a numerical example and an example of an inverted pendulum on a cart.

Finite‐time event‐triggered control for a class of cascade switched affine nonlinear systems

AbstractThis paper is concerned with the finite‐time boundedness (FTB) problem of a class of cascade switched affine nonlinear systems. In order to avoid unnecessary waste of network communication and Zeno behavior, a dynamical event‐triggered scheme is proposed, which is more general than some existing event‐triggered schemes with a common parameter matrix. By using the average dwell time method and multiple Lyapunov function technologies, sufficient conditions for the existence of controller gains are first proposed such that the closed‐loop system is finite‐time bounded with a finite‐time disturbance attenuation performance. It is also proved that the Zeno phenomenon is excluded. Finally, a numerical example is given to illustrate the feasibility and effectiveness of the proposed method.