Composite Anti-disturbance Control Research Articles

Fixed-Time Composite Anti-Disturbance Control for Flexible-Link Manipulators Based on Disturbance Observer

Fixed-Time Composite Anti-Disturbance Control for Flexible-Link Manipulators Based on Disturbance Observer

Refined disturbance observer based prescribed performance fixed-time control of high-speed EMS trains with track irregularities

High-speed Electromagnetic Suspension (EMS) train is continuously impacted by the irregularity of the track, which worsens the levitation performance of the train. In this paper, a composite control scheme for the EMS is proposed to suppress track irregularities by integrating a Refined Disturbance Observer (RDO) and a Prescribed Performance Fixed-Time Controller (PPFTC). The RDO is designed to estimate precisely the track irregularities and lumped disturbances with uncertainties and exogenous disturbances in the suspension system, and reduce input chattering by applying to the disturbance compensation channel. PPFTC is designed to converge the suspension air gap error to equilibrium point with prescribed performance by completing error conversion, and solve the fast dynamic issue of EMS. And the boundary of overshoot and steady-state is limited in the ranged prescribed. A theoretical analysis is conducted on the stability of the proposed control method. Finally, the effectiveness and reasonability of the proposed composite anti-disturbance control scheme is verified by simulation results.

Disturbance-Observer-Based Finite-Time Antidisturbance Control for Markov Switched Descriptor Systems With Multi-Disturbances and Intermittent Measurements

This paper is concerned with the finite time <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_\infty$</tex-math> </inline-formula> composite anti-disturbance control problem for Markov switched descriptor systems with multiple disturbances and packet loss via a disturbance observer. Significantly, the switching topology of descriptor systems is controlled by nonhomogeneous Markov switching processes, whose time-varying transition probability is limited by a convex hull. Subsequently, a Bernoulli random variable is exploited to characterize the intermittent measurement mode behavior of controller-actuator packet loss. Furthermore, the stochastic <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$H_\infty$</tex-math> </inline-formula> finite time boundiness of the composite system and simultaneously suppression and rejection of external disturbances are established by resorting to disturbance observer-based robust control (DOBC) strategy and a new stochastic Lyapunov function technique. More importantly, a relaxed variable method is provided to eliminate the coupling between Lyapunov variables and the system matrix in the process of stability analysis, instead of eliminating the coupling by means of commonly-used traditional inequalities, which effectively increases the flexibility of the obtained stable results and greatly reduces the computational complexity of controller/observer in the existing works. Finally, the effectiveness and practicability of the developed results are verified by two practical engineering models.

Composite anti-disturbance control for ship dynamic positioning systems with thruster faults

Anti-disturbance control problem is studied for ship dynamic positioning systems with model uncertainties and ocean disturbances under thruster faults. For the ocean disturbance, a stochastic disturbance observer (SDO) is established to give the online estimation. For thruster faults, an adaptive law is used to evaluate, which is obtain from Lyapunov function. For model uncertainties, a robust control term with adaptive technology is used to attenuate it. Then, a composite anti-disturbance control (CADC) strategy is raised by combining disturbance observer-based control (DOBC), adaptive technology, and robust control term, which makes the position and yaw angle of ship reach the desired values. Finally, the simulation example proves the validity of the controller.

Adaptive composite anti-disturbance control for heavy haul trains

Abstract In this paper, an adaptive composite anti-disturbance control of heavy haul trains (HHTs) is proposed. First, the mechanical principle and characteristics of couplers are analysed and the longitudinal multi-particles nonlinear dynamic model of HHTs is established, which can satisfy that the forces of vehicles in different positions are different. Subsequently, a radial basis function network (RBFNN) is employed to approximate the uncertainties of HHTs, and a nonlinear disturbance observer (NDO) is constructed to estimate the approximation error and external disturbances. To indicate and improve the approximation accuracy, a serial-parallel identification model of HHTs is constructed to generate a prediction error, and an adaptive composite anti-disturbance control scheme is developed, where the prediction error and tracking error are employed to update RBFNN weights and an auxiliary variable of NDO. Finally, the feasibility and effectiveness of the proposed control scheme are demonstrated through the Lyapunov theory and simulation experiments.

Functional Observer-based Asynchronous Composite Anti-Disturbance Control for Markov Jump Systems with Multiple Disturbances

Multiple disturbances under multi channels in Markov jump systems (MJSs) lead to the asynchronism between controller modes and system modes, thus restricting the control performance of systems. This paper investigates functional observer-based asynchronous composite anti-disturbance control for MJSs with matched and mismatched disturbances. First, a functional observer-based asynchronous composite integral sliding mode control with H∞ performance index (ACISMC-H∞) framework is proposed to reject the matched disturbance and attenuate the norm-bounded disturbance simultaneously. On the one hand, a functional observer based control is proposed to estimate partly unavailable states and the matched disturbance generated by an exogenous system and compensate the matched disturbance. Meanwhile, the parameters of the observer can be found directly. On the other hand, a novel ACISMC-H∞ is designed to attenuate the norm-bounded mismatched disturbance and ensure that the system state trajectories can always stay on the sliding surface. Due to the asynchronism between system modes and controller modes, the hidden Markov model is employed to detect model information in controller design. Second, sufficient conditions are proposed to achieve the stochastic stability and satisfy H∞ performance of closed-loop MJSs. It is worth noting that the functional observer directly estimates the linear function of exogenous system states, that is, the matched disturbance, which reduces the observer order and computational load. Finally, a numerical example is given to illustrate the effectiveness of our proposed method.

Observer-Based Event-Triggered Composite Anti-Disturbance Control for Multi-Agent Systems Under Multiple Disturbances and Stochastic FDIAs

This article aims to investigate the security consensus and composite anti-disturbance problems for a class of nonlinear multi-agent systems subjected to stochastic false data injection attacks (FDIAs) and multiple disturbances under a directed communication topology. To attenuate and reject of the negative effects of two types of disturbances, a disturbance observer (DO) is designed to counteract the disturbance produced by exogenous system, and the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\mathcal {H}_\infty $ </tex-math></inline-formula> control method is adopted to attenuate the bounded errors and variables caused by the other type of disturbances and FDIAs simultaneously. To ensure the consensus performance of MASs, an observer-based control strategy is designed, and a novel adaptive compensation technique is proposed to not only evaluate the upper bounds of the unknown but bounded disturbances but also improve the accuracy of the state observer. Furthermore, a novel event-triggered mechanism (ETM) without requiring continuous communication among neighboring agents is developed to reduce the controller update frequency and the communication burden. Meanwhile, Zeno behavior is excluded. Finally, numerical simulations are provided to verify the availability of the designed method. Note to Practitioners—In multi-agent systems, network security is very important. For example, in smart power grid systems, it is necessary to use the method of state estimation to observe the system to guarantee its safe operation. However, the measured value of the instrument may be affected by FDIAs in the transmission process, thus changing the result of state estimation and causing misjudgment of the system. Similarly, in multi-vehicle systems, FDIAs may destroy the location information of vehicles and cause serious accidents. In addition, the system will be subjected to different types of disturbances in practice, thus reducing the performance of the system. In view of the threat of FDIAs and disturbances to the MAS, a composite anti-disturbance method and an observer-based control strategy are proposed. Meanwhile, to avoid the limitation of communication bandwidth in reality, a novel ETM is developed to save network resources.

Uncertain Disturbance Attenuation and Rejection for Interval Type-2 Fuzzy Systems via Disturbance Observer

This study is concerned with the composite anti-disturbance issue for nonlinear systems subject to state saturation and parameter uncertainties, including the unknown harmonic disturbance. First, an interval type-2 (IT2) Takagi–Sugeno fuzzy model is proposed herein to describe the nonlinear system with state saturation and parametric uncertainties. Next, a novel disturbance observer framework is designed to eliminate the unknown harmonic disturbance. By introducing the new framework, the expression of the unknown harmonic disturbance is transformed into a new expression having only an uncertain parameter, which is then estimated. The corresponding composite anti-disturbance control scheme is then put forward and the sufficient conditions guaranteeing the stochastically stable of the composite system are established. Finally, the simulations are conducted to confirm the availability of the this control scheme.

Composite disturbance observer-based backstepping stabilisation for 3-DOF ship-borne platform with unknown disturbances

ABSTRACT A composite anti-disturbance stabilisation control scheme is presented for the ship-borne platform system with completely unknown disturbances. The completely unknown disturbances consist of external time-varying disturbances and norm-bounded unmodelled dynamics. The composite anti-disturbance control scheme is built through integrating the nonlinear disturbance observer and the robustifying term with the vectorial backstepping technique. The nonlinear disturbance observer is designed to provide the on-line estimations of external time-varying disturbances such that the disturbance compensation term is introduced into the control design. The robustifying term with the adaptive law is employed to attenuate norm-bounded unmodelled dynamics. On the basis of the vectorial backstepping technique, the composite anti-disturbance control law is derived. The composite anti-disturbance control structure consists of the outer layer with the nonlinear disturbance observer for external time-varying disturbance cancellation as well as the inner layer with the vectorial backstepping control together with the robustifying term for unmodelled dynamic attenuation. By means of the Lyapunov stability theory, it is proven that the composite anti-disturbance stabilisation controller can achieve the disturbance rejection and attenuation simultaneously. It is verified by illustrative simulations that the composite anti-disturbance stabilisation control scheme can effectively stabilise the ship-borne stabilisation platform.

Finite-Time Composite Antidisturbance Control for T–S Fuzzy Nonhomogeneous Markovian Jump Systems via Asynchronous Disturbance Observer

This article studies the finite-time composite antidisturbance control problem for nonhomogeneous Markovian jump systems (MJSs) subject to multiple disturbances via the Takagi–Sugeno (T–S) fuzzy control scheme. The designed two-gains disturbance observer (DO) and the considered MJSs are supposed to switch the different Markovian chains, which are depicted by a hidden Markovian model. Herein, an asynchronous DO design is explored for the first time, providing new insight into the construction of asynchronous DO. First, the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$H_\infty /L_{2}-L_\infty$</tex-math></inline-formula> finite-time boundedness of the augmented system is guaranteed. Second, based on the Finsler lemma, the linearization issue in calculating observer/controller gain is addressed. Finally, two illustrations are presented to verify the effectiveness of the proposed method.

Anti-disturbance observer-based control for fuzzy chaotic semi-Markov jump systems with multiple disturbances and mixed actuator failures

This article develops robust stabilization and anti-disturbance control design for fuzzy chaotic semi-Markov jump systems with randomly occurring uncertainties, nonlinear actuator faults, matched and mismatched disturbances. Primarily, the matched disturbances stimulated from the exogenous systems are dealt with by constructing a disturbance observer. At the same time, mismatched part is handled by the extended passivity performance. Additionally, the actuator fault model which encompasses both linear and nonlinear characteristics is put forward in the controller design. Thus, by taking advantage of the parallel distributed compensation methodology, a composite anti-disturbance control is framed by combining the fuzzy rule-based nonlinear fault-tolerant controller and estimation of the disturbance. Thereafter, by selecting relevant mode-dependent Lyapunov function candidate, adequate criteria are acquired in the context of linear matrix inequalities to ensure robust asymptotic stability along with the endorsed extended passivity performance level for the closed-loop system. In due course, by solving the developed inequalities under the aegis of MATLAB platform, the gain matrices of the devised controller and the framed disturbance observer are obtained. Last of all, to validate the effectiveness and applicability of the theoretical findings, simulation results of standard Chua’s circuit system, Lorenz system and Rössler system are exploited.

Robust Stabilization for a Class of Nonlinear Positive Systems With Multiple Disturbances

In this article, a composite anti-disturbance control of disturbance rejection and attenuation for a class of nonlinear positive systems is proposed for the first time to achieve both positivity and stability. The disturbance observer-based control (DOBC) method is utilized to compensate for the effects of the modeled disturbances, while the <inline-formula> <tex-math notation="LaTeX">$L_{1}$ </tex-math></inline-formula> control strategy is adopted to suppress the effects of the disturbances which are not compensable to satisfy the <inline-formula> <tex-math notation="LaTeX">$L_{1}$ </tex-math></inline-formula> index performance. Besides, two analysis schemes of the closed-loop system are presented. The first scheme is commonly used and is easy for analysis, but it has some conservativeness. The second scheme is proposed novelly with less conservativeness, which releases the positivity constraint of disturbance estimation errors. The corresponding theorems and algorithms are proposed for necessary conditions and solutions. Finally, two examples are presented to illustrate the effectiveness of the proposed control schemes.

Anti-disturbance composite tracking control for a coupled two-tank MIMO process with experimental studies

Coupled multiple-tank systems are very important for a wide range of industrial applications due to their unique uses. However, the liquid level control for the coupled two-tank multi-input multi-output (MIMO) system is quite challenging because it has strong nonlinearity and coupling, and it is susceptible to multiple external disturbances. For this process, this paper proposes a novel anti-disturbance control strategy consisting on a nonlinear composite hierarchical anti-disturbance predictive control (CHADPC). First, a model-based explicit nonlinear model predictive controller (ENMPC) is designed assuming that all disturbances are measurable and its global exponential stability is proved. Then, a nonlinear disturbance observer (DO) is designed to estimate the lumped disturbances. The composite controller handling the estimated disturbances is then proposed. Finally, simulation and experimental tracking control tests under perturbations and comparisons with recently reported works have been carried out to highlight the promising performance of the proposed ENMPC and CHADPC schemes.

Composite anti-disturbance quantized control for interconnected semi-Markovian systems with multiple disturbances and actuator faults

This paper investigates the composite anti-disturbance control problem for the interconnected Semi-Markovian systems with multiple disturbances and actuator faults, where the state signal of each subsystem is quantized by logarithmic quantizer before being transmitted into controller. Two representative types of external disturbances are considered simultaneously, one is norm-bounded and the other is formulated by an exogenous system. To attenuate the modelling disturbance and diagnose the actuator faults, a distributed disturbance observer with fault diagnosis observer is constructed. Then, the composite quantized control methodology is proposed to compensate disturbances and faults, and stabilize the overall system. On the basis of proper Semi-Markovian Lyapunov-Krasovskii functional, some sufficient criterions are derived to ensure the stochastic stability with a prescribed performance. Moreover, the desired observer and controller gain matrices can be attained via linear matrix inequalities (LMIs) technique. Finally, a simulation example is given to demonstrate the feasibility and effectiveness of theoretical results.

Composite anti-disturbance position and attitude control for spacecrafts with parametric uncertainty and flexible vibration

The rendezvous and proximity operations with respect to a tumbling non-cooperative target pose high requirement for the position and attitude control accuracy of servicing spacecraft. However, multiple disturbances including parametric uncertainties, flexible vibration, and unknown nonlinear dynamics degrade the control performance significantly. In order to enhance the system anti-disturbance ability, this paper proposes a composite anti-disturbance control law for the spacecraft position and attitude tracking. Firstly, the relative position and attitude dynamic models with multiple disturbances are established, where the refined descriptions of multiple disturbances are accomplished based on their characteristics. Then, by combining a dual Disturbance Observer-Based Control (DOBC) and a sliding mode control, a composite controller with hierarchical architecture is proposed, where the dual DOBC in the feedforward channel is used to reject the flexible vibration, environment disturbance, and complicated nonlinear dynamics, while the parametric uncertainties are attenuated by the sliding mode control in the feedback channel. Stability analysis is carried out for the closed-loop system by unifying the sliding mode dynamics and observer dynamics. Finally, the effectiveness of the proposed controller is verified via numerical simulation and hardware-in-the-loop test.

An adaptive composite disturbance rejection for attitude control of the agricultural quadrotor UAV

Aiming at the problem that agricultural quadrotor UAV is easily disturbed in ultra-low altitude phenotype remote sensing and precision hovering of spraying, an adaptive composite anti-disturbance attitude controller is proposed for ground effect and propeller failure disturbances rejection. The adaptive composite disturbance rejection control (ACDRC) is composed of active disturbance rejection control (ADRC) and disturbance observer (DO) based on nominal inverse model, which is used to estimate wind disturbance, payload disturbance and propeller failure disturbance in real time. For the bandwidth tuning of the extended state observer (ESO), an online tuning method based on iterative learning control (ILC) is proposed to realize the adaptive extended state observer (ESO). And the stability of the composite anti-disturbance controller is analyzed. In the experiments, the wind disturbance experiments under the side-down flow and the horizontal flow, the failure experiments under the single propeller failure and twin propeller failure, and the composite disturbances experiments under the simultaneous action of the wind disturbance, propeller failure and payload disturbance are carried out. The experimental results show that under wind disturbance, the anti-disturbance performance of ACDRC is increased by 82.5%; under the disturbance of propeller fault, the anti-disturbance performance of ACDRC is increased by 60%; under the composite disturbance, the anti-disturbance performance of ACDRC is increased by 50%. Finally, the effectiveness of ACDRC is further verified in vegetable and cotton fields.

Uncertain Disturbance Rejection and Attenuation for Semi-Markov Jump Systems With Application to 2-Degree-Freedom Robot Arm

This paper studies the composite refined anti-disturbance control problem of a 2-degree-of-freedom robot arm system modeled by a semi-Markov jump system with multiple disturbances, which includes harmonic disturbances with unknown frequency and amplitude as well as energy bounded disturbances. Firstly, the semi-Markov jump system model is proposed to construct a novel linear model of the 2-degree-of-freedom robot arm subject to two types of disturbances. Next, in order to estimate the uncertain harmonic disturbance, a novel higher order disturbance observer is introduced to convert the uncertain harmonic disturbance into some parameter uncertainty and then estimate the parameter uncertainty. In addition, a corresponding composite anti-disturbance control scheme is formulated to reject and attenuate the above two types of disturbances, respectively. Furthermore, sufficient conditions that can guarantee that the system is stochastically stable are given. Finally, a simulation study of the obtained model is carried out to illustrate the validity of the composite control design method proposed in this paper.

Integral Sliding Mode Anti-Disturbance Control for Markovian Jump Systems with Mismatched Disturbances

This paper addresses an integral sliding mode-based anti-disturbance control algorithm for a type of Markovian jump systems (MJSs), which are influenced by different types of mismatched disturbances. On one hand, as for those disturbances that can be modeled, the disturbance observer (DO) method is introduced to realize the dynamical estimation of disturbances. Based on this, both the integral sliding surface (ISS) and the composite anti-disturbance controller are proposed in succession for rejecting unknown disturbances and guaranteeing the stability of the controlled MJS. Meanwhile, the states of the controlled system are ensured to reach ISS within a finite time. In addition, the L1 performance index is given to attenuate the effects of bounded disturbances. The controller and observer gains can be computed by using convex optimization techniques. The satisfactory stochastic stability and dynamical tracking performance are both also proved. Finally, the simulation results effectively verify all of the required performances.

Adaptive fuzzy-based composite anti-disturbance control for a class of switched nonlinear systems with unknown backlash-like hysteresis

For a class of switched nonlinear systems with unmatched external disturbances and unknown backlash-like hysteresis, an adaptive fuzzy-based control strategy is proposed to handle the anti-disturbance issue. The unmatched external disturbances come from a switched exosystem. Our aim is to achieve the output tracking performance and the disturbance attenuation by using the adaptive fuzzy-based composite anti-disturbance control technique. First, based on the fuzzy logics, we design a switching adaptive fuzzy disturbance observer to estimate unmatched external disturbances. Second, a composite switching adaptive anti-disturbance controller is constructed. By means of the backstepping technique, disturbance estimations are added in each virtual control to offset the unmatched disturbances, which results in the different coordinate transformations. At last, the availability of the proposed approach is illustrated by a mass-spring-damper system.

Finite-time boundedness analysis and composite anti-disturbance control for uncertain semi-Markovian jump systems with time delay

Finite-time boundedness analysis and composite anti-disturbance control for uncertain semi-Markovian jump systems with time delay