Composite Hierarchical Anti-disturbance Control Research Articles

Dynamic Positioning Control for Marine Crafts: A Survey and Recent Advances

This paper surveys the recent advances in dynamic positioning (DP) control for marine crafts. DP of marine crafts means that a craft can maintain a fixed position and heading, or move along a predetermined trajectory slowly without the anchoring system, using only its own thruster system to counteract ocean disturbances. The survey is by no means exhaustive but provides a survey of some of the major technological advancements in DP controller design over the years of research and development. Firstly, the model of marine crafts and some difficult problems in DP control are introduced including the impact of multiple source disturbance, unavailable velocity measurement information, resource conservation and performance optimization, destabilizing impact of faults and network security and compound multi-constraint restrictions. Then, the DP control schemes in recent years are summarized and classified in detail. Finally, some theoretical and technical problems are proposed, including online data-driven model-free control, man–machine combination intelligent control and composite hierarchical anti-disturbance control to guide future investigations.

Composite Control for Gimbal Systems With Multiple Disturbances: Analysis, Design, and Experiment

The proportional-integral (PI) controller has proven to be a remarkably effective control strategy in the servo field. However, it is difficult for PI to handle the problem of multiple disturbances degrading the velocity-tracking capability of the gimbal system in the control moment gyro (CMG). In this article, we propose a solution to this problem while preserving the advantages of PI from an engineering standpoint. Starting from the refined disturbance analysis based on a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5$</tex-math> </inline-formula> Nms CMG gimbal system experimental tests, multiple disturbances of the gimbal system can be classified according to frequency distribution in terms of 0 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim$</tex-math> </inline-formula> 5 and 128 Hz. Subsequently, under the composite hierarchical anti-disturbance control frame, a peak filter and a disturbance observer addition improve the anti-disturbance capability of the PI-based gimbal system at the frequencies of 0 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim$</tex-math> </inline-formula> 5 and 128 Hz. Notably, the proposed method has a relatively low order, which is appropriate for the processing power limit. Finally, the experimental results reveal that compared to three effective control schemes (PI, extended state observer-based composite controller, and PI-resonant controller), the proposed method can strikingly enhance the anti-disturbance ability and velocity-tracking performance of the gimbal system.

SPT-Based Composite Hierarchical Antidisturbance Control Applied to a Quadrotor UAV

Although the flight control of quadrotor unmanned aerial vehicles have been widely studied, it is still very challenging to suppress multiple disturbances and efficiently utilize the inherent multi time-scale characteristics. As a well-known antidisturbance strategy, composite hierarchical antidisturbance control (CHADC) can compensate and attenuate disturbances simultaneously, thus enhancing the control performance of complex systems significantly. In the meantime, the singular perturbation theory (SPT) is employed to analyze the multi time-scale properties, and the original system is decomposed into the slow and fast subsystems. In this article, we present an antidisturbance control scheme based on the SPT and CHADC to enhance the capability of antidisturbance. A novel composite hierarchical antidisturbance (CHAD) predictor–corrector is proposed for the slow subsystem to integratively handle the disturbances from guidance and control perspective, and a CHAD <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> controller is employed for the fast subsystem subject to external disturbances and inertial uncertainties. Meanwhile, the compensability of disturbance is explicitly analyzed. Finally, experiments are carried out to validate the effectiveness of the proposed scheme.

Composite Antidisturbance Control for Non-Gaussian Stochastic Systems via Information-Theoretic Learning Technique.

In this article, a novel composite hierarchical antidisturbance control (CHADC) algorithm aided by the information-theoretic learning (ITL) technique is developed for non-Gaussian stochastic systems subject to dynamic disturbances. The whole control process consists of some time-domain intervals called batches. Within each batch, a CHADC scheme is applied to the system, where a disturbance observer (DO) is employed to estimate the dynamic disturbance and a composite control strategy integrating feedforward compensation and feedback control is adopted. The information-theoretic measure (entropy or information potential) is employed to quantify the randomness of the controlled system, based on which the gain matrices of DO and feedback controller are updated between two adjacent batches. In this way, the mean-square stability is guaranteed within each batch, and the system performance is improved along with the progress of batches. The proposed algorithm has enhanced disturbance rejection ability and good applicability to non-Gaussian noise environment, which contributes to extending CHADC theory to the general stochastic case. Finally, simulation examples are included to verify the effectiveness of theoretical results.

Composite hierarchical anti-disturbance control for dynamic positioning system of ships based on robust wave filter

The composite hierarchical anti-disturbance control (CHADC) strategy is investigated for dynamical position system of ships(DP) with multiple disturbances, which include slowly varying environmental disturbances, first-order wave-induced disturbances and additional disturbances. The ship’s velocities and the slowly varying environmental disturbances are estimated by designing state observer and disturbance observer, respectively. Subsequently, a robust wave filter (RWF) is constructed to deal with the first-order wave-induced disturbances, which assures a prescribed performance level for the filter error system. The CHADC strategy is proposed by integrating stochastic disturbance observer-based control (DOBC) theory, RWF method with H∞ control, such that high control accuracy of the DP system can be realized. Efficacy of the proposed control strategy is illustrated through the example of a supply ship.

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.

The path-following control of the underactuated AUV with input saturation and multiple disturbances

Autonomous underwater vehicle (AUV) in marine resource surveys plays an important role. This paper proposes a new path-following control frame for the underactuated AUV with input saturation and multiple disturbances. The disturbances include external disturbances, model parameter uncertainties, unmodeled dynamics and other random disturbances. Compared to most of previously published literatures, which treat disturbances as lumped disturbances, a composite hierarchical anti-disturbance control (CHADC) strategy is adopted to achieve higher precision path following. A disturbance observer (DOB) is constructed to estimate and eliminate the disturbances with partial known information, while the H ∞ theory is used to optimize the path-following controller to attenuate the other disturbances satisfying the L 2-norm bound condition and improve the robustness of system. Besides, Lyapunov direct method and back-stepping method are used to design the path-following controller, where the input saturation is considered, the extended state observer (ESO) is used to estimate the uncertainty of kinematic controller and the nonlinear tracking differentiator (NTD) is used to simplify the controller. Finally, simulations are given to demonstrate the effectiveness of the proposed control law.

Dual-Disturbance Observers-Based Control for a Class of Singularly Perturbed Systems

Singularly perturbed systems (SPSs) wildly exist in practical engineering practice; however, the disturbance rejection in SPSs is still a problem. As well-known disturbance rejection methods, composite hierarchical anti-disturbance control (CHADC) can effectively compensate and suppress disturbance, which improves the control performances of complex systems. To enhance the capability of anti-disturbance and control precision, this article proposes a novel composite hierarchical anti-disturbance (CHAD) dynamic surface control (DSC) for the fast subsystem considering highly dynamic disturbance, and CHAD proportion-integration (PI) control for the slow subsystem with slow-varying harmonic disturbance. The disturbances are supposed to be generated by an exogenous system based on partially known information with model uncertainty, and the stabilities of both fast and slow closed-loop subsystems are analyzed. Meanwhile, the compensability of disturbances is discussed. Finally, simulations for an F-8 aircraft are given to demonstrate the effectiveness of the proposed methods.

Multi-Body Dynamics Modeling and Control for Strapdown Inertially Stabilized Platforms Considering Light Base Support Characteristics

The dynamics model used for inertially or strapdown inertially stabilized platforms is based on the rotor and motor load, and it either does not consider the stator or it implicitly assumes a fixed stator. It has been determined that vibrations occur in the system when a controller is used in strapdown inertially stabilized platforms with a light base support. As the system is also affected by multi-source disturbances, which are the main factors that affect the control accuracy. For the above two problems, this paper originally establishes a multi-body dynamics model including the controller. The composite controller not only suppresses the vibration successfully, but also greatly improves the disturbance compensation and tracking performance of the strapdown inertially stabilized platforms. Specifically, a modified feedback controller is used to suppress the vibrations analyzed according to the dynamics model. The friction feedforward and residual disturbance observer facilitates the design of compound disturbance compensation on the basis of composite hierarchical anti-disturbance control. To emphasize the advantages of strapdown inertially stabilized platforms, the feedforward controller employs feedforward angular velocity and acceleration. The results of the numerical analysis and experiments indicate that vibrations are successfully suppressed and tracking accuracy and disturbance isolation ability are improved.

Disturbance-Observer-Based Fault Tolerant Control of High-Speed Trains: A Markovian Jump System Model Approach

This paper addresses the fault tolerant control problem for high-speed trains in case of multiple possible failures. A new multiple point-mass model with system faults is built based on a stochastic jump system model approach. A novel active fault tolerant composite hierarchical anti-disturbance control strategy based on the disturbance observer is proposed such that the resulting composite system is stochastically stable with position and velocity tracking performance. According to whether the transition probabilities (TPs) of the failure and fault detection and isolation process can be accessed completely, three different cases (TPs are completely known, partially known, and completely unknown) are analyzed. For each case, based on the Lyapunov functional approach, a composite hierarchical controller is synthesized via a convex optimization problem. Finally, the simulations are given to illustrate the performance of the proposed methodologies.

Composite hierarchical anti-disturbance control for stochastic systems with multiple heterogeneous disturbances

This paper studies the problem of anti-disturbance control for a class of stochastic systems with multiple heterogeneous disturbances, which include the white noise and the non-harmonic disturbance with unknown nonlinear function. An adaptive disturbance observer is constructed to estimate the non-harmonic disturbances with unknown nonlinear function, which is approximated by neural network. A composite hierarchical anti-disturbance control (CHADC) scheme is designed by integrated Lyapunov function and linear matrix inequality (LMI), such that the expected dynamic performance of the composite system is achieved. Finally, simulations show that the approach is proper and effective.

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.

Composite hierarchical antidisturbance control for a class of discrete‐time stochastic systems

SummaryIn this paper, antidisturbance control and estimation problem are discussed for a class of discrete‐time stochastic systems with nonlinearity and multiple disturbances, which include the disturbance with partially known information and a sequence of random vectors. A disturbance observer is constructed to estimate the disturbance with partially known information. A composite hierarchical antidisturbance control scheme is proposed by combining disturbance observer and H∞ control. It is proved that the 2 different disturbances can be rejected and attenuated, and the corresponding desired performances can be guaranteed for discrete‐time stochastic systems with known and unknown nonlinear dynamics, respectively. Simulation examples are given to demonstrate the effectiveness of the proposed scheme.

Composite Hierarchical Anti-Disturbance Control of a Quadrotor UAV in the Presence of Matched and Mismatched Disturbances

Quadrotor helicopter is an unstable system subject to matched and mismatched disturbances. To stabilize the quadrotor dynamics in the presence of these disturbances, the application of a composite hierarchical anti-disturbance controller, combining a sliding mode controller and a disturbance observer, is presented in this paper. The disturbance observer is used to attenuate the effect of constant and slow time-varying disturbances. Whereas, the sliding mode controller is used to attenuate the effect of fast time-varying disturbances. In addition, sliding mode control attenuates the effect of the disturbance observer estimation errors of the constant and slow time-varying disturbances. In this approach, the upper bounds of the disturbance observer estimation errors are required instead of the disturbances’ upper bounds. The disturbance observer estimation errors are found to be bounded when the disturbance observer dynamics are asymptotically stable and the disturbance derivatives and initial disturbances are bounded. Moreover, due to the highly nonlinear nature of the quadrotor dynamics, the upper bounds of a part of the quadrotor states and disturbance estimates are required. The nonlinear terms in the rotational dynamics are considered as disturbances, part of which is mismatched. This assumption simplifies the control system design by dividing the quadrotor’s model into a position subsystem and a heading subsystem, and designing a controller for each separately. The stability analysis of the closed loop system is carried out using Lyapunov stability arguments. The effectiveness of the developed control scheme is demonstrated in simulations by applying different sources of disturbances such as wind gusts and partial actuator failure.

Composite hierarchical anti-disturbance control for stochastic systems with multiple disturbances

A class of stochastic systems with multiple disturbances, which includes white noises and disturbances whose time derivative is bounded, is considered in this paper. To estimate the unknown bounded disturbance, a stochastic disturbance observer is proposed. Based on the observer, a disturbance observer-based disturbance control scheme is constructed such that the composite closed-loop system is asymptotically bounded. Finally, a simulation example is given to demonstrate the feasibility and effectiveness of the proposed scheme.

Constrained anti-disturbance control for a quadrotor based on differential flatness

ABSTRACTThe classical control design based on linearised model is widely used in practice even to those inherently nonlinear systems. Although linear design techniques are relatively mature and enjoy the simple structure in implementations, they can be prone to misbehaviour and failure when the system state is far away from the operating point. To avoid the drawbacks and exploit the advantages of linear design methods while tackling the system nonlinearity, a hybrid control structure is developed in this paper. First, the model predictive control is used to impose states and inputs constraints on the linearised model, which makes the linearisation satisfy the small-perturbation requirement and reduces the bound of linearisation error. On the other hand, a combination of disturbance observer-based control and H∞ control, called composite hierarchical anti-disturbance control, is constructed for the linear model to provide robustness against multiple disturbances. The constrained reference states and inputs generated by the outer-loop model predictive controller are asymptotically tracked by the inner-loop composite anti-disturbance controller. To demonstrate the performance of the proposed framework, a case study on quadrotor is conducted.

Disturbance-Observer-Based Control and Related Methods—An Overview

Disturbance-observer-based control (DOBC) and related methods have been researched and applied in various industrial sectors in the last four decades. This survey, at first time, gives a systematic and comprehensive tutorial and summary on the existing disturbance/uncertainty estimation and attenuation techniques, most notably, DOBC, active disturbance rejection control, disturbance accommodation control, and composite hierarchical antidisturbance control. In all of these methods, disturbance and uncertainty are, in general, lumped together, and an observation mechanism is employed to estimate the total disturbance. This paper first reviews a number of widely used linear and nonlinear disturbance/uncertainty estimation techniques and then discusses and compares various compensation techniques and the procedures of integrating disturbance/uncertainty compensation with a (predesigned) linear/nonlinear controller. It also provides concise tutorials of the main methods in this area with clear descriptions of their features. The application of this group of methods in various industrial sections is reviewed, with emphasis on the commercialization of some algorithms. The survey is ended with the discussion of future directions.

Composite Hierarchical Antidisturbance Control for Magnetic Bearing System Subject to Multiple External Disturbances

This paper explores a composite hierarchical antidisturbance control (CHADC) scheme for the resonance vibration suppression of a high-speed rotor system supported by active magnetic bearings (AMBs) in the magnetically suspended double-gimbal control moment gyroscope (MSDGCMG). The rotor dynamics with a fictitious integral term is introduced to meet the steady-state performance requirements. Resonance disturbances caused by harmonic drive transmission and gyroscopic torque disturbances caused by gimbal motions are also analyzed. The augmented composite AMB system with two types of disturbances and nonlinear electromagnetic dynamics is developed. Then, a disturbance observer is constructed and a stability analysis of the closed-loop system is performed using a Lyapunov approach. Simulation results show that the exogenous disturbance can be estimated and compensated with the appropriate control parameters. Rotor run-up experiments demonstrate that the proposed method has a good performance for disturbance rejection of harmonic drive resonance vibrations under the excitation of coupling torques. The gyroscopic torque disturbances with the bounded norm can also be attenuated effectively.

Disturbance‐observer‐based control &amp; ℋ ∞ control for non‐linear Markovian jump singular systems with multiple disturbances

This study addresses the Problem of composite hierarchical anti-disturbance control [disturbance-observer-based controllers (DOBC) and ℋ∞ control] for Markovian jump singular systems with non-linearity and two types of disturbances (the first is generated by an exogenous system and the latter is norm-bounded). The authors’ attention is focused on the design of a disturbance observer to estimate the first disturbance, and then on constructing a composite hierarchical control scheme such that the solution to the composite system is unique and exists, the composite system can be guaranteed to be stochastically admissible, and different types of disturbances can be attenuated and rejected simultaneously. By constructing a proper stochastic Lyapunov–Krasovskii functional, sufficient conditions for the existence of the desired DOBCs are established. Finally, a numerical eEEExample is provided to show the effectiveness of the proposed approaches.

Composite hierarchical anti-disturbance control for robotic systems with multiple disturbances

Various sources of disturbances exist simultaneously in robotic systems, such as vibrations, frictions, measurement noises, and equivalent disturbances from unmodeled dynamics and nonlinearities. However, most results on anti-disturbance control focus on only one type of disturbances, which cannot reflect the real applications and may lead to design conservativeness due to partial use of the disturbance information. In this paper, we propose a composite hierarchical anti-disturbance control (CHADC) strategy for robotic systems in the presence of multiple disturbances as well as system uncertainties. Particularly, we assume the existence of two types of disturbances, where the first type represents disturbances from exogenous systems with model perturbations, while the second type includes other random disturbances satisfying the L2-norm bound condition. Accordingly, the CHADC control architecture is composed of a nonlinear disturbance observer (NDO) and an H∞ based PID controller, where the NDO is constructed to estimate the first type of disturbances and provide feed forward compensation, while the feedback PID loop is optimized using H∞ theory to minimize the second type of disturbances. Robustness against system uncertainties is also considered in this hierarchical control structure. The proposed control approach is applied to a two-link robotic manipulator and compared with the conventional DOBC (disturbance observer based control) strategies.