Multi-source Disturbances Research Articles

Barrier Lyapunov Functions-Based Adaptive Fault Tolerant Control for Flexible Hypersonic Flight Vehicles With Full State Constraints

One of the key problems for space vehicles is how to deal with the contradiction between the control constraints and the disturbances from multiple resources. This paper focuses on the adaptive full state constrained controller design problem for the flexible air-breathing hypersonic vehicles with multisource uncertainties. In simultaneous presence of the aerodynamical uncertainties, the modeling errors, the external disturbances, and the contingent actuator failures, an adaptive fault-tolerant control scheme is put forward in the context of dynamic surface control. Then, the barrier Lyapunov functions are utilized to guarantee that the constraints on the velocity, the flight path angle, the altitude, and the pitch rate are never violated. In virtue of the bound estimation approach, the multisource disturbances are effectively dealt with. Finally, a number of illustrative examples are provided to demonstrate the effectiveness of the proposed methodology.

Nonlinear disturbance observer based adaptive super-twisting sliding mode control for generic hypersonic vehicles with coupled multisource disturbances

In practical, there often exist structural uncertainties, measurement errors, and the aerodynamic perturbations in the flight control systems of the hypersonic vehicles (HSVs). The control performance degradation and loss of stability may be induced if the coupled multisource uncertainties are ignored. To address this problem, this paper develops a novel multivariable robust adaptive sliding mode control structure. Benefiting from the second-order characteristics of the super-twisting controller, the uncertainties from the unknown nonlinearities and the lumped disturbances can be surmounted respectively. Meanwhile, the finite time convergence can be obtained and the continuity of the control signals can be guaranteed. Moreover, to cope with the unknown upper bounds of lumped uncertainties, a novel update law is developed by analyzing the connection between the control gains and the boundaries. Moreover, for the purpose of compensating the mismatched uncertainties in HSVs, a robust disturbance observer is introduced into the sliding surface such that the sliding-mode dynamics are stable with L2−L∞ performance. The closed-loop control system is proved to be globally ultimately stable. Simulation results indicate that the proposed control scheme works well compared with the existing methods.

Adaptive Static Output Feedback Anti-disturbance Quantized Control for Nonlinear Systems with Multi-source Disturbances

In this paper, the problem of adaptive static output feedback anti-disturbance quantized control is proposed for nonlinear systems with multi-source disturbances and unknown parameters. Using the output information, the disturbance observer and the adaptive law are constructed. An adaptive static output feedback anti-disturbance quantized controller is designed by combining with the estimated values of the disturbance and unknown parameters, in which a compensation term is introduced to eliminate the influence of quantization error. The stability and H∞ performance are analyzed by using Lyapunov function method. Finally, a simulation example is given to verify the validity of the results.

Dissipativity-Based Disturbance Attenuation Control for T-S Fuzzy Markov Jumping Systems With Nonlinear Multisource Uncertainties and Partly Unknown Transition Probabilities.

This article is concerned with the dissipativity-based disturbance attenuation control for a class of Takagi-Sugeno (T-S) fuzzy Markov jump systems (FMJSs) suffering from nonlinear multisource disturbances. The considered system possesses nonlinear and stochastic jumping disturbances generated by multiple sources, constituting the main challenge to control design and dissipativity analysis. By proposing an adaptive fuzzy disturbance observer and a hybrid feedback controller, a novel fuzzy disturbance attenuation control structure has been constructed. In terms of strict linear matrix inequalities (LMIs), a new sufficient condition is established to guarantee the (Z, Y, X)-ε- dissipative and stochastic exponentially stability of the closed-loop FMJSs. Furthermore, for the concerned FMJSs with partly unknown transition probabilities, the sufficient conditions are also derived and the gains of controller or observer can be computed immediately. Finally, a numerical example is provided to verify the effectiveness of the proposed theory.

Dissipativity-Based Composite Antidisturbance Control for T–S Fuzzy Switched Stochastic Nonlinear Systems Subjected to Multisource Disturbances

In this article, a dissipativity-based composite antidisturbance control structure is constructed for Takagi–Sugeno (T–S) fuzzy switched stochastic nonlinear systems subjected to multisource disturbances. The inherent uncertain nonlinear and hybrid characteristics of the concerned system make it difficult to design a stable antidisturbance controller. To properly accommodate the characteristics of T–S fuzzy multisource disturbances and system models, a novel fuzzy switched disturbance observer is put forward to estimate the disturbances generated by a switched exogenous system. Then, a fuzzy composite antidisturbance control law is synthesized by fusing the estimation of the multisource disturbances and the state-feedback control scheme. By using the average dwell time technique and piecewise Lyapunov functions, it is proved that the resultant closed-loop system are stochastically stable and strictly $({{\mathscr Z},{\mathscr Y},{\mathscr X}})-\varepsilon -$ dissipative. The sufficient conditions for the existence of the fuzzy switched disturbance observer and state-feedback controller are established in terms of linear matrix inequalities, and the control and observation gains can be solved directly. Finally, a numerical example is presented to illustrate the effectiveness and favor performance of the proposed control algorithm.

A High Precision Compound Control Scheme Based on Non-singular Terminal Sliding Mode and Extended State Observer for an Aerial Inertially Stabilized Platform

This paper presents a high precision compound control scheme based on non-singular terminal sliding mode and extended state observer (ESO) for an aerial inertially stabilized platform (ISP) to suppress the effects of multi-source disturbances on the control performance of the ISP. Firstly, a non-singular terminal sliding mode controller is proposed to achieve high disturbance rejection ability, by which the multi-source disturbances are integrally suppressed as an aggregate disturbance. And then, to restrain the chattering effect of the sliding mode control, a disturbance compensation scheme based on the extended state observer is proposed. By the ESO, the disturbances are observed and compensated in real time and hence the chattering effect is significantly alleviated. Meanwhile, a parameter configuration method is proposed to simplify the ESO design. To verify the method, simulations and experiments are conducted. The results show that the proposed compound control scheme has excellent ability in both disturbance rejection and chattering reduction, by which the stabilization precision of the ISP is improved significantly.

Output Feedback H∞ Control for Linear Discrete-Time Multi-Player Systems With Multi-Source Disturbances Using Off-Policy Q-Learning

In this paper, a data-driven optimal control method based on adaptive dynamic programming and game theory is presented for solving the output feedback solutions of the $H_\infty $ control problem for linear discrete-time systems with multiple players subject to multi-source disturbances. We first transform the $H_\infty $ control problem into a multi-player game problem following the theoretical solutions according to game theory. Since the system state may not be measurable, we derive the output feedback based control policies and disturbances through mathematical operations. Considering the advantages of off-policy reinforcement learning (RL) over on-policy RL, a novel off-policy game Q-learning algorithm dealing with mixed competition and cooperation among players is developed, such that the $H_\infty $ control problem can be finally solved for linear multi-player systems without the knowledge of system dynamics. Moreover, rigorous proofs of algorithm convergence and unbiasedness of solutions are presented. Finally, simulation results demonstrated the effectiveness of the proposed method.

Composite DOBC with fuzzy fault‐tolerant control for stochastic systems with unknown nonlinear dynamics

SummaryA class of stochastic nonlinear systems with fault and multisource disturbances is concerned. The fault is a general bounded actuator fault, and the multiple disturbances include partial‐known information disturbance and white noise. A stochastic adaptive disturbance observer is constructed to estimate the partial‐known information disturbance, based on which the partial‐known information disturbance can be compensated in the feed‐foreword channel immediately. Also, the multiplicative white noise can be attenuated by the designed feedback controller. To make the composite system is satisfactory, a composite disturbance based‐observer control with fuzzy fault‐tolerant control is proposed. The pole placement and LMI method is applied to attenuate and reject the disturbance. Furthermore, the fault can be compensated simultaneously. To verify the feasibility and availability of the designed control scheme, a simulation example is shown finally.

Composite Hierarchical Anti-Disturbance Control with Multisensor Fusion for Compact Optoelectronic Platforms.

In the aerospace field, compact optoelectronic platforms (COPs) are being increasingly equipped on unmanned aircraft systems (UAS). They assist UAS in a range of mission-specific tasks such as disaster relief, crop testing, and firefighting. However, the strict constraint of structure space makes COPs subject to multi-source disturbances. The application of a low-cost and low-precision sensor also affects the system control performance. A composite hierarchical anti-disturbance control (CHADC) scheme with multisensor fusion is explored herein to improve the motion performance of COPs in the presence of internal and external disturbances. Composite disturbance modelling combining the characteristic of wire-wound moment is presented in the inner layer. The adaptive mutation differential evolution algorithm is implemented to identify and optimise the model parameters of the system internal disturbance. Inverse model compensation and finite-time nonlinear disturbance observer are then constructed to compensate for multiple disturbances. A non-singular terminal sliding mode controller is constructed to attenuate disturbance in the outer layer. A stability analysis for both the composite disturbance compensator and the closed-loop system is provided using Lyapunov stability arguments. The phase lag-free low-pass filter is implemented to interfuse multiple sensors with different order information and achieve satisfactory noise suppression without phase lag. Experimental results demonstrate that the proposed CHADC strategy with a higher-quality signal has an improved performance for multi-source disturbance compensation.

Nonlinear augmented state observer-based adaptive output feedback anti-disturbance control for nonlinear systems with non-harmonic multiple uncertainties

In this paper, a novel output feedback anti-disturbance control method is carried out for a class of nonlinear systems subject to non-harmonic multisource disturbances. By using a nonlinear exogenous system, a class of non-harmonic disturbances possessing complex and nonlinear characteristics are taken fully into consideration. Based on a nonlinear damping term, we establish an adaptive augmented state observer that can achieve robust asymptotic disturbance estimation for the system states, the harmonic disturbances and the non-harmonic disturbances. By fusing the augmented state observer and a state-feedback controller, a robust adaptive output feedback anti-disturbance control structure is constructed. The boundness of the combined controller–observer system is derived on the basis of Lyapunov analysis. Furthermore, aiming at the intense non-harmonic disturbances, the proposed method is extended and a new output feedback controller is obtained. The effectiveness of the proposed scheme is demonstrated through experimental studies on a practical example.

A GA-based parameters tuning method for an ADRC controller of ISP for aerial remote sensing applications

This paper presents a parameters tuning method based on the genetic algorithm (GA) for an active disturbance rejection control (ADRC) of a three-axis inertially stabilized platform (ISP) with imaging sensors. To improve the stabilization accuracy and robustness of an aerial ISP under multi-source disturbances environment, an ADRC control scheme is first proposed. Then, to accurately identify and tune the parameters in the ADRC controller, a GA-based parameters tuning method is proposed. In this way, the performance of the ADRC is superior to the empirical method. To validate the proposed method, the simulations and experiments are carried out. The results show that the proposed ADRC with GA-based parameters tuning method has significant disturbance rejection ability which can improve the stabilization accuracy obviously. Compared with the ADRC with empirically tuning method, the stabilization error (RMS) under movable base is decreased up to 50.09%.

A High-Precision Control Scheme Based on Active Disturbance Rejection Control for a Three-Axis Inertially Stabilized Platform for Aerial Remote Sensing Applications

This paper presents a high-precision control scheme based on active disturbance rejection control (ADRC) to improve the stabilization accuracy of an inertially stabilized platform (ISP) for aerial remote sensing applications. The ADRC controller is designed to suppress the effects of the disturbance on the stabilization accuracy that consists of a tracking differentiator, a nonlinear state error feedback, and an extended state observer. By the ADRC controller, the effects of both the internal uncertain dynamics and the external multisource disturbances on the system output are compensated as a total disturbance in real time. The disturbance rejection ability of the ADRC is analyzed by simulations. To verify the method, the experiments are conducted. The results show that compared with the conventional PID controller, the ADRC has excellent capability in disturbance rejection, by which the effect of main friction disturbance on the control system can be weakened seriously and the stabilization accuracy of the ISP is improved significantly.

Decentralized adaptive fault tolerant control for a class of interconnected systems with nonlinear multisource disturbances

In this paper, a decentralized adaptive backstepping control scheme is proposed for a class of interconnected systems with nonlinear multisource disturbances and actuator faults. The nonlinear multisource disturbances comprise of two parts: one is the time-varying parameterized uncertainty; the other is the dynamic unexpected signal formulated by a nonlinear exogenous system. For each subsystem, the disturbances are compensated by an adaptive controller based on several dynamic signals and the bound estimation approach. Moreover, the effect of the actuator faults is tackled in spite of the fact that the faults may change in different cases infinite times. Meanwhile, through several smooth functions, the interactions among the subsystems are successfully disposed. As a result, the tracking errors can converge to an arbitrarily small value by choosing the design parameters appropriately. The proof of the closed-loop system stability is completed. Several illustrative examples are employed to demonstrate the effectiveness of the proposed method.

Robust fault detection for the dynamics of high-speed train with multi-source finite frequency interference

This paper proposes a composite fault detection scheme for the dynamics of high-speed train (HST), using an unknown input observer-like (UIO-like) fault detection filter, in the presence of wind gust and operating noises which are modeled as disturbance generated by exogenous system and unknown multi-source disturbance within finite frequency domain. Using system input and system output measurements, the fault detection filter is designed to generate the needed residual signals. In order to decouple disturbance from residual signals without truncating the influence of faults, this paper proposes a method to partition the disturbance into two parts. One subset of the disturbance does not appear in residual dynamics, and the influence of the other subset is constrained by H∞ performance index in a finite frequency domain. A set of detection subspaces are defined, and every different fault is assigned to its own detection subspace to guarantee the residual signals are diagonally affected promptly by the faults. Simulations are conducted to demonstrate the effectiveness and merits of the proposed method.

Non-linear disturbance observer-based adaptive composite anti-disturbance control for non-linear systems with dynamic non-harmonic multisource disturbances

In this paper, an adaptive composite anti-disturbance control structure is constructed for a class of non-linear systems with dynamic non-harmonic multisource disturbances. The key point of this paper is that a kind of non-harmonic disturbance, which has non-linear internal dynamics and complex features, is involved. A non-linear exogenous system is employed to describe the dynamic non-harmonic disturbances and several useful assumptions are introduced. By introducing a non-linear damping term, a novel adaptive non-linear disturbance observer is constructed. Based on the disturbance/uncertainty estimation and attenuation (DUEA) schemes, a composite anti-disturbance control structure is synthesized. Meanwhile, a new sufficient condition is derived and the stability of the closed-loop system is proved. Several illustrative examples are employed to demonstrate the effectiveness of the proposed method.

Adaptive output feedback disturbance attenuation control for nonlinear systems with non-harmonic multisource disturbances

This paper focuses on the output feedback regulation for a class nonlinear systems with dynamic non-harmonic multisource disturbances. The key point of this paper is that a kind of non-harmonic disturbances, which have complex nonlinear features, are investigated by using a nonlinear exogenous system. By introducing a nonlinear damping term, a novel adaptive augmented state observer is constructed to estimate the system states, the harmonic disturbances and the non-harmonic disturbances. By integrating the output of the observer with an anti-disturbance controller, an output feedback disturbance attenuation control structure is synthesized such that the closed-loop stability can be guaranteed. Moreover, the results are extended to the disturbances which have intense non-harmonic characteristics. Several illustrative examples are employed to demonstrate the effectiveness of the proposed control structure.

Composite anti-disturbance control for a class of uncertain nonlinear systems via a disturbance observer

A new anti-disturbance control scheme is proposed for a class of nonlinear systems subjected to multi-source disturbances. The uncertain multi-source disturbances are classified into two parts; one is the harmonic and constant disturbance with partial known information, which can be formulated by an exogenous system, and the other consists of unknown time-varying disturbances. The nonlinear disturbance observer (NDO) is constructed to estimate the first kind of disturbance. By integrating the NDO with an adaptive backstepping technique, a novel composite anti-disturbance control scheme is proposed for the nonlinear systems. Then the stability analysis of the closed-loop system is presented. The simulation of a numerical example is given to demonstrate the effectiveness of the proposed results.

The composite hierarchical control of multi-link multi-DOF space manipulator based on UDE and improved sliding mode control

The problem of manipulating objects cooperatively for multi-link multi-degree of freedom space manipulator is very challenging because of the multisource disturbances, including nonlinear coupling, model uncertainties, and external disturbances. To solve this issue, a composite hierarchical control strategy is proposed, which has two layers. In inner layer, uncertainty and disturbance estimator (UDE) is employed to estimate the composite uncertainty that comprises the effect of multisource disturbances and compensate for it, producing the decoupled system. Furthermore, taking the error in UDE estimation into consideration, the chattering–eliminating sliding mode control is designed to suppress it in the outer layer. However, the obtained controller requires the measurement of joint velocities apart from joint positions. To address this issue, a robust velocity observer that employs the UDE-estimated uncertainty is proposed. The notable feature of the proposed design is that it requires neither accurate plant model nor any information about the uncertainty. Also, the design requires only joint position measurements for its implementation. Finally, to demonstrate the effectiveness of the composite hierarchical controller, the simulations of a planar dual-arm manipulator system and the comparisons of the proposed method with the other existing designs are presented.

Anti-Interference Optimal Design of Grain Combine Harvester Multiple Target Working Speed Control Model

Harvesting speed is a key factor that influences working quality, utilization and harvest efficiency of the working process of grain combine harvester. In order to solve multi-objective control and poor anti-interference ability of measurement system in combine harvester, this paper uses optimization theory and error analysis theory to integrate analyze multi-source disturbance of data which is acquired in measurement and control system. The optimum working state control algorithm which proposes by this paper has better robust and anti-interference features, and what is more, it can be targeted by low yield loss, high productivity and low power cost. It provides theoretical basis and data support for the domestic agricultural harvesting machine, which also is an effective means to heighten the automatic level of the agricultural information technology. Keywords: Grain Combine harvester; Multiple control strategy; Anti-interference ability

Composite adaptive disturbance observer‐based control for a class of nonlinear systems with multisource disturbance

SUMMARYAntidisturbance control and estimation problem are introduced for a class of nonlinear system subject to multisource disturbances. The uncertain multisource disturbances consist of not only a single harmonic or constant disturbance but also another unexpected nonlinear signal described as a nonlinear function. The composite adaptive disturbance observers are constructed separately from the controller design to estimate the disturbance with partial known information. By integrating disturbance observer‐based controller with robust adaptive control, a novel type of composite adaptive disturbance observer‐based control scheme is presented for a class of nonlinear system with multisource disturbances. Simulations for a flight control system are given to demonstrate the effectiveness of the results compared with the previous schemes. Copyright © 2012 John Wiley & Sons, Ltd.