Engineering › Control and Systems Engineering

Adaptive Control of Nonlinear Systems

Works Count: 71303

Wikipedia

Description

This cluster of papers focuses on advanced control and stabilization techniques for robotic systems, particularly emphasizing adaptive control, sliding mode control, disturbance observer-based control, and finite-time stability in the context of nonlinear systems. The applications range from quadrotors and aerial vehicles to robotic manipulators, with a strong emphasis on addressing uncertainties and disturbances in the control process.

Keywords

Adaptive Control; Sliding Mode Control; Disturbance Observer; Nonlinear Systems; Finite-Time Stability; Quadrotor; Neural Network; Feedback Control; Robotic Manipulators; Aerial Vehicles

The internal model principle of control theory

1976-09-01

Bruce A. Francis , W.M. Wonham

Gaussian Networks for Direct Adaptive Control

1991-06-01

Robert M. Sanner , Jean-Jacques Slotine

A direct adaptive tracking control architecture is proposed and evaluated for a class of continuous-time nonlinear dynamic systems for which an explicit linear parameterization of the uncertainty in the dynamics … A direct adaptive tracking control architecture is proposed and evaluated for a class of continuous-time nonlinear dynamic systems for which an explicit linear parameterization of the uncertainty in the dynamics is either unknown or impossible. The architecture employs a network of gausian radial basis functions to adaptively compensate for the plant nonlinearities. Under mild assumptions about the degree of smoothness exhibited by the nonlinear functions, the algorithm is proven to be stable, with tracking errors converging to a neighborhood of zero. A constructive procedure is detailed, which directly translates the assumed smoothness properties of the nonlinearities involved into a specification of the network required to represent the plant to a chosen degree of accuracy. A stable weight adjustment mechanism is then determined using Lyapunov theory. The network construction and performance of the resulting controller are illustrated through simulations with an example system.

Guidance and Control of Ocean Vehicles

1994-01-01

Thor I. Fossen

Modeling of Marine Vehicles. Environmental Disturbances. Stability and Control of Underwater Vehicles. Dynamics and Stability of Ships. Automatic Control of Ships. Control of High--Speed Craft. Appendices. Bibliography. Index. Modeling of Marine Vehicles. Environmental Disturbances. Stability and Control of Underwater Vehicles. Dynamics and Stability of Ships. Automatic Control of Ships. Control of High--Speed Craft. Appendices. Bibliography. Index.

Stability of switched systems with average dwell-time

2003-01-22

João P. Hespanha , A. Stephen Morse

It is shown that switching among stable linear systems results in a stable system provided that switching is "slow-on-the-average". In particular, it is proved that exponential stability is achieved when … It is shown that switching among stable linear systems results in a stable system provided that switching is "slow-on-the-average". In particular, it is proved that exponential stability is achieved when the number of switches in any finite interval grows linearly with the length of the interval, and the growth rate is sufficiently small. Moreover, the exponential stability is uniform over all switchings with the above property. For switched systems with inputs this guarantees that several input-to-state induced norms are bounded uniformly over all slow-on-the-average switchings. These results extend to classes of nonlinear switched systems that satisfy suitable uniformity assumptions. In this paper it is also shown that, in a supervisory control context, scale-independent hysteresis can produce switching that is slow-on-the-average and therefore the results mentioned above can be used to study the stability of hysteresis-based adaptive control systems.

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Multirotor Aerial Vehicles: Modeling, Estimation, and Control of Quadrotor

2012-08-28

Robert Mahony , Vijay Kumar , Peter Corke

This article provides a tutorial introduction to modeling, estimation, and control formultirotor aerial vehicles that includes the common four-rotor or quadrotor case. This article provides a tutorial introduction to modeling, estimation, and control formultirotor aerial vehicles that includes the common four-rotor or quadrotor case.

Global finite-time stabilization of a class of uncertain nonlinear systems

2005-03-12

Xianqing Huang , Wei Lin , Bo Yang

Adaptive Neural Network Control of an Uncertain Robot With Full-State Constraints

2015-04-03

Wei He , Yuhao Chen , Zhao Yin

This paper studies the tracking control problem for an uncertain ${n}$ -link robot with full-state constraints. The rigid robotic manipulator is described as a multiinput and multioutput system. Adaptive neural … This paper studies the tracking control problem for an uncertain ${n}$ -link robot with full-state constraints. The rigid robotic manipulator is described as a multiinput and multioutput system. Adaptive neural network (NN) control for the robotic system with full-state constraints is designed. In the control design, the adaptive NNs are adopted to handle system uncertainties and disturbances. The Moore-Penrose inverse term is employed in order to prevent the violation of the full-state constraints. A barrier Lyapunov function is used to guarantee the uniform ultimate boundedness of the closed-loop system. The control performance of the closed-loop system is guaranteed by appropriately choosing the design parameters. Simulation studies are performed to illustrate the effectiveness of the proposed control.

Non-singular terminal sliding mode control of rigid manipulators

2002-10-28

Yong Feng , Xinghuo Yu , Zhihong Man

Sliding controller design for non-linear systems

1984-08-01

Jean-Jacques Slotine

Abstract New results are presented on the sliding control methodology introduced by Slotine and Sastry (1983) to achieve accurate tracking for a class of non-linear time-varying multivariate systems in the … Abstract New results are presented on the sliding control methodology introduced by Slotine and Sastry (1983) to achieve accurate tracking for a class of non-linear time-varying multivariate systems in the presence of disturbances and parameter variations. An explicit trade-off is obtained between tracking precision and robustness to modelling uncertainty : tracking accuracy is sot according to the extent, of parametric uncertainty and the frequency range of unmodelled dynamics. The trade-off is further refined to account for time-dependence of model uncertainty.

Higher-order sliding modes, differentiation and output-feedback control

2003-01-01

Arie Levant

Being a motion on a discontinuity set of a dynamic system, sliding mode is used to keep accurately a given constraint and features theoretically-infinite-frequency switching. Standard sliding modes provide for … Being a motion on a discontinuity set of a dynamic system, sliding mode is used to keep accurately a given constraint and features theoretically-infinite-frequency switching. Standard sliding modes provide for finite-time convergence, precise keeping of the constraint and robustness with respect to internal and external disturbances. Yet the relative degree of the constraint has to be 1 and a dangerous chattering effect is possible. Higher-order sliding modes preserve or generalize the main properties of the standard sliding mode and remove the above restrictions. r-Sliding mode realization provides for up to the rth order of sliding precision with respect to the sampling interval compared with the first order of the standard sliding mode. Such controllers require higher-order real-time derivatives of the outputs to be available. The lacking information is achieved by means of proposed arbitrary-order robust exact differentiators with finite-time convergence. These differentiators feature optimal asymptotics with respect to input noises and can be used for numerical differentiation as well. The resulting controllers provide for the full output-feedback real-time control of any output variable of an uncertain dynamic system, if its relative degree is known and constant. The theoretical results are confirmed by computer simulation.

Variable structure control of nonlinear multivariable systems: a tutorial

1988-03-01

Raymond A. DeCarlo , Stanisław H. Żak , Gregory P. Matthews

The design of variable-structure control (VSC) systems for a class of multivariable, nonlinear, time-varying systems is presented. Using the Utkin-Drazenovic method of equivalent control and generalized Lyapunov stability concepts, the … The design of variable-structure control (VSC) systems for a class of multivariable, nonlinear, time-varying systems is presented. Using the Utkin-Drazenovic method of equivalent control and generalized Lyapunov stability concepts, the VSC design is described in a unified manner. Complications that arise due to multiple inputs are examined, and several approaches useful in overcoming them are developed. Recent developments are investigated, as is the kinship of VSC and the deterministic approach to the control of uncertain systems. All points are illustrated by numerical examples. The recent literature on VSC applications is surveyed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Sliding-Mode Control for Systems With Mismatched Uncertainties via a Disturbance Observer

2012-01-11

Jun Yang , Shihua Li , Xinghuo Yu

This paper develops a sliding-mode control (SMC) approach for systems with mismatched uncertainties via a nonlinear disturbance observer (DOB). By designing a novel sliding surface based on the disturbance estimation, … This paper develops a sliding-mode control (SMC) approach for systems with mismatched uncertainties via a nonlinear disturbance observer (DOB). By designing a novel sliding surface based on the disturbance estimation, a DOB-based SMC method is developed in this paper to counteract the mismatched disturbance. The newly proposed method exhibits the following two attractive features. First, the switching gain is only required to be designed greater than the bound of the disturbance estimation error rather than that of the disturbance; thus, the chattering problem is substantially alleviated. Second, the proposed method retains its nominal performance, which means the proposed method acts the same as the baseline sliding-mode controller in the absence of uncertainties. Simulation results of both the numerical and application examples show that the proposed method exhibits much better control performance than the baseline SMC and the integral SMC (I-SMC) methods, such as reduced chattering and nominal performance recovery.

Nonlinear Feedback Design for Fixed-Time Stabilization of Linear Control Systems

2011-12-15

Andrey Polyakov

Two types of nonlinear control algorithms are presented for uncertain linear plants. Controllers of the first type are stabilizing polynomial feedbacks that allow to adjust a guaranteed convergence time of … Two types of nonlinear control algorithms are presented for uncertain linear plants. Controllers of the first type are stabilizing polynomial feedbacks that allow to adjust a guaranteed convergence time of system trajectories into a prespecified neighborhood of the origin independently on initial conditions. The control design procedure uses block control principles and finite-time attractivity properties of polynomial feedbacks. Controllers of the second type are modifications of the second order sliding mode control algorithms. They provide global finite-time stability of the closed-loop system and allow to adjust a guaranteed settling time independently on initial conditions. Control algorithms are presented for both single-input and multi-input systems. Theoretical results are supported by numerical simulations.

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Sliding order and sliding accuracy in sliding mode control

1993-12-01

Arie Levant

Abstract The synthesis of a control algorithm that stirs a nonlinear system to a given manifold and keeps it within this constraint is considered. Usually, what is called sliding mode … Abstract The synthesis of a control algorithm that stirs a nonlinear system to a given manifold and keeps it within this constraint is considered. Usually, what is called sliding mode is employed in such synthesis. This sliding mode is characterized, in practice, by a high-frequency switching of the control. It turns out that the deviation of the system from its prescribed constraints (sliding accuracy) is proportional to the switching time delay. A new class of sliding modes and algorithms is presented and the concept of sliding mode order is introduced. These algorithms feature a bounded control continuously depending on time, with discontinuities only in the control derivative. It is also shown that the sliding accuracy is proportional to the square of the switching time delay. Additional informationNotes on contributorsARIE LEVANTFormerly, L. V. Levantovsky

Continuous state feedback guaranteeing uniform ultimate boundedness for uncertain dynamic systems

1981-10-01

M. Corless , G. Leitmann

We consider a dynamic system containing uncertain elements. Only the set of possible values of these uncertainties is known. Based on this information a class of state feedback controls is … We consider a dynamic system containing uncertain elements. Only the set of possible values of these uncertainties is known. Based on this information a class of state feedback controls is proposed in order to guarantee uniform ultimate boundedness of every system response within an arbitrarily small neighborhood of the zero state. These feedback controls are continuous functions of the state.

Strict Lyapunov Functions for the Super-Twisting Algorithm

2012-02-01

Jaime A. Moreno , Marisol Osorio

A method to construct a family of strict Lyapunov functions, i.e., with negative definite derivative, for the super-twisting algorithm, without or with perturbations, is provided. This second order sliding modes … A method to construct a family of strict Lyapunov functions, i.e., with negative definite derivative, for the super-twisting algorithm, without or with perturbations, is provided. This second order sliding modes algorithm is widely used to design controllers, observers and exact differentiators. The proposed Lyapunov functions ascertain finite time convergence, provide an estimate of the convergence time, and ensure the robustness of the finite-time or ultimate boundedness for a class of perturbations wider than the classical ones for this algorithm. Since the Lyapunov functions and their derivatives are quadratic forms, the operation with them is as simple as for linear time invariant systems.

Small-gain theorem for ISS systems and applications

1994-06-01

Z.-P. Jiang , Andrew R. Teel , Laurent Praly

Input-to-state stability for discrete-time nonlinear systems

2001-06-01

Zhong‐Ping Jiang , Yuan Wang

A ‘universal’ construction of Artstein's theorem on nonlinear stabilization

1989-08-01

Eduardo D. Sontag

Stable adaptive neural control scheme for nonlinear systems

1996-03-01

Marios M. Polycarpou

Based on the Lyapunov synthesis approach, several adaptive neural control schemes have been developed during the last few years. So far, these schemes have been applied only to simple classes … Based on the Lyapunov synthesis approach, several adaptive neural control schemes have been developed during the last few years. So far, these schemes have been applied only to simple classes of nonlinear systems. This paper develops a design methodology that expands the class of nonlinear systems that adaptive neural control schemes can be applied to and relaxes some of the restrictive assumptions that are usually made. One such assumption is the requirement of a known bound on the network reconstruction error. The overall adaptive scheme is shown to guarantee semiglobal uniform ultimate boundedness. The proposed feedback control law is a smooth function of the state.

Robust adaptive control

1995-10-15

Pétros Ioannou , Jing Sun

1. Introduction. Control System Design Steps. Adaptive Control. A Brief History. 2. Models for Dynamic Systems. Introduction. State-Space Models. Input/Output Models. Plant Parametric Models. Problems. 3. Stability. Introduction. Preliminaries. Input/Output … 1. Introduction. Control System Design Steps. Adaptive Control. A Brief History. 2. Models for Dynamic Systems. Introduction. State-Space Models. Input/Output Models. Plant Parametric Models. Problems. 3. Stability. Introduction. Preliminaries. Input/Output Stability. Lyapunov Stability. Positive Real Functions and Stability. Stability of LTI Feedback System. Problems. 4. On-Line Parameter Estimation. Introduction. Simple Examples. Adaptive Laws with Normalization. Adaptive Laws with Projection. Bilinear Parametric Model. Hybrid Adaptive Laws. Summary of Adaptive Laws. Parameter Convergence Proofs. Problems. 5. Parameter Identifiers and Adaptive Observers. Introduction. Parameter Identifiers. Adaptive Observers. Adaptive Observer with Auxiliary Input. Adaptive Observers for Nonminimal Plant Models. Parameter Convergence Proofs. Problems. 6. Model Reference Adaptive Control. Introduction. Simple Direct MRAC Schemes. MRC for SISO Plants. Direct MRAC with Unnormalized Adaptive Laws. Direct MRAC with Normalized Adaptive Laws. Indirect MRAC. Relaxation of Assumptions in MRAC. Stability Proofs in MRAC Schemes. Problems. 7. Adaptive Pole Placement Control. Introduction. Simple APPC Schemes. PPC: Known Plant Parameters. Indirect APPC Schemes. Hybrid APPC Schemes. Stabilizability Issues and Modified APPC. Stability Proofs. Problems. 8. Robust Adaptive Laws. Introduction. Plant Uncertainties and Robust Control. Instability Phenomena in Adaptive Systems. Modifications for Robustness: Simple Examples. Robust Adaptive Laws. Summary of Robust Adaptive Laws. Problems. 9. Robust Adaptive Control Schemes. Introduction. Robust Identifiers and Adaptive Observers. Robust MRAC. Performance Improvement of MRAC. Robust APPC Schemes. Adaptive Control of LTV Plants. Adaptive Control for Multivariable Plants. Stability Proofs of Robust MRAC Schemes. Stability Proofs of Robust APPC Schemes. Problems. Appendices. Swapping Lemmas. Optimization Techniques. Bibliography. Index. License Agreement and Limited Warranty.

Robust Adaptive Control of Feedback Linearizable MIMO Nonlinear Systems With Prescribed Performance

2008-10-01

Charalampos P. Bechlioulis , George A. Rovithakis

A novel robust adaptive controller for multi-input multi-output (MIMO) feedback linearizable nonlinear systems possessing unknown nonlinearities, capable of guaranteeing a prescribed performance, is developed in this paper. By prescribed performance … A novel robust adaptive controller for multi-input multi-output (MIMO) feedback linearizable nonlinear systems possessing unknown nonlinearities, capable of guaranteeing a prescribed performance, is developed in this paper. By prescribed performance we mean that the tracking error should converge to an arbitrarily small residual set, with convergence rate no less than a prespecified value, exhibiting a maximum overshoot less than a sufficiently small prespecified constant. Visualizing the prescribed performance characteristics as tracking error constraints, the key idea is to transform the ldquoconstrainedrdquo system into an equivalent ldquounconstrainedrdquo one, via an appropriately defined output error transformation. It is shown that stabilization of the ldquounconstrainedrdquo system is sufficient to solve the stated problem. Besides guaranteeing a uniform ultimate boundedness property for the transformed output error and the uniform boundedness for all other signals in the closed loop, the proposed robust adaptive controller is smooth with easily selected parameter values and successfully bypasses the loss of controllability issue. Simulation results on a two-link robot, clarify and verify the approach.

Sliding mode control design principles and applications to electric drives

1993-02-01

Vadim Utkin

The basic concepts, mathematics, and design aspects of variable-structure systems as well as those with sliding modes as a principle operation mode are treated. The main arguments in favor of … The basic concepts, mathematics, and design aspects of variable-structure systems as well as those with sliding modes as a principle operation mode are treated. The main arguments in favor of sliding-mode control are order reduction, decoupling design procedure, disturbance rejection, insensitivity to parameter variations, and simple implementation by means of power converters. The control algorithms and data processing used in variable structure systems are analyzed. The potential of sliding mode control methodology is demonstrated for versatility of electric drives and functional goals of control.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Neural Network-Based Adaptive Dynamic Surface Control for a Class of Uncertain Nonlinear Systems in Strict-Feedback Form

2005-01-01

Dan Wang , Jie Huang

The dynamic surface control (DSC) technique was developed recently by Swaroop et al. This technique simplified the backstepping design for the control of nonlinear systems in strict-feedback form by overcoming … The dynamic surface control (DSC) technique was developed recently by Swaroop et al. This technique simplified the backstepping design for the control of nonlinear systems in strict-feedback form by overcoming the problem of "explosion of complexity." It was later extended to adaptive backstepping design for nonlinear systems with linearly parameterized uncertainty. In this paper, by incorporating this design technique into a neural network based adaptive control design framework, we have developed a backstepping based control design for a class of nonlinear systems in strict-feedback form with arbitrary uncertainty. Our development is able to eliminate the problem of "explosion of complexity" inherent in the existing method. In addition, a stability analysis is given which shows that our control law can guarantee the uniformly ultimate boundedness of the solution of the closed-loop system, and make the tracking error arbitrarily small.

Passivity, feedback equivalence, and the global stabilization of minimum phase nonlinear systems

1991-01-01

C.I. Byrnes , Alberto Isidori , Jan C. Willems

Conditions under which a nonlinear system can be rendered passive via smooth state feedback are derived. It is shown that, as in the case of linear systems, this is possible … Conditions under which a nonlinear system can be rendered passive via smooth state feedback are derived. It is shown that, as in the case of linear systems, this is possible if and only if the system in question has relative degree one and is weakly minimum phase. It is proven that weakly minimum phase nonlinear systems with relative degree one can be globally asymptotically stabilized by smooth state feedback, provided that suitable controllability-like rank conditions are satisfied. This result incorporates and extends a number of stabilization schemes recently proposed for global asymptotic stabilization of certain classes of nonlinear systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

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Disturbance Observer Based Control for Nonlinear Systems

2004-12-01

Wen‐Hua Chen

This work presents a general framework for nonlinear systems subject to disturbances using disturbance observer based control (DOBC) techniques. A two-stage design procedure to improve disturbance attenuation ability of current … This work presents a general framework for nonlinear systems subject to disturbances using disturbance observer based control (DOBC) techniques. A two-stage design procedure to improve disturbance attenuation ability of current linear/nonlinear controllers is proposed where the disturbance observer design is separated from the controller design. To facilitate this concept, a nonlinear disturbance observer is developed for disturbances generated by an exogenous system, and global exponential stability is established under certain condition. Furthermore, semiglobal stability condition of the composite controller consisting of a nonlinear controller and the nonlinear disturbance observer is established. The developed method is illustrated by the application to control of a two-link robotic manipulator.

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L/sub 2/-gain analysis of nonlinear systems and nonlinear state-feedback H/sub infinity / control

1992-06-01

Arjan van der Schaft

Previously obtained results on L2-gain analysis of smooth nonlinear systems are unified and extended using an approach based on Hamilton-Jacobi equations and inequalities, and their relation to invariant manifolds of … Previously obtained results on L2-gain analysis of smooth nonlinear systems are unified and extended using an approach based on Hamilton-Jacobi equations and inequalities, and their relation to invariant manifolds of an associated Hamiltonian vector field. On the basis of these results a nonlinear analog is obtained of the simplest part of a state-space approach to linear H/sub infinity / control, namely the state feedback H/sub infinity / optimal control problem. Furthermore, the relation with H/sub infinity / control of the linearized system is dealt with.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

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Geometric tracking control of a quadrotor UAV on SE(3)

2010-12-01

Taeyoung Lee , Melvin Leok , N. Harris McClamroch

This paper provides new results for the tracking control of a quadrotor unmanned aerial vehicle (UAV). The UAV has four input degrees of freedom, namely the magnitudes of the four … This paper provides new results for the tracking control of a quadrotor unmanned aerial vehicle (UAV). The UAV has four input degrees of freedom, namely the magnitudes of the four rotor thrusts, that are used to control the six translational and rotational degrees of freedom, and to achieve asymptotic tracking of four outputs, namely, three position variables for the vehicle center of mass and the direction of one vehicle body-fixed axis. A globally defined model of the quadrotor UAV rigid body dynamics is introduced as a basis for the analysis. A nonlinear tracking controller is developed on the special Euclidean group SE(3) and it is shown to have desirable closed loop properties that are almost global. Several numerical examples, including an example in which the quadrotor recovers from being initially upside down, illustrate the versatility of the controller.

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A simple observer for nonlinear systems applications to bioreactors

1992-06-01

Jean-Yves Gauthier , H. Hammouri , Sami Othman

An observer for nonlinear systems is constructed under rather general technical assumptions (the fact that some functions are globally Lipschitz). This observer works either for autonomous systems or for nonlinear … An observer for nonlinear systems is constructed under rather general technical assumptions (the fact that some functions are globally Lipschitz). This observer works either for autonomous systems or for nonlinear systems that are observable for any input. A tentative application to biological systems is described.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Variable structure control: a survey

1993-01-01

John Y. Hung , W.B. Gao , J. C. Hung

A tutorial account of variable structure control with sliding mode is presented. The purpose is to introduce in a concise manner the fundamental theory, main results, and practical applications of … A tutorial account of variable structure control with sliding mode is presented. The purpose is to introduce in a concise manner the fundamental theory, main results, and practical applications of this powerful control system design approach. This approach is particularly attractive for the control of nonlinear systems. Prominent characteristics such as invariance, robustness, order reduction, and control chattering are discussed in detail. Methods for coping with chattering are presented. Both linear and nonlinear systems are considered. Future research areas are suggested and an extensive list of references is included.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Second-order sliding-mode observer for mechanical systems

2005-11-01

Jorge Dávila , Leonid Fridman , Arie Levant

The super-twisting second-order sliding-mode algorithm is modified in order to design a velocity observer for uncertain mechanical systems. The finite time convergence of the observer is proved. Thus, the observer … The super-twisting second-order sliding-mode algorithm is modified in order to design a velocity observer for uncertain mechanical systems. The finite time convergence of the observer is proved. Thus, the observer can be designed independently of the controller. A discrete version of the observer is considered and the corresponding accuracy is estimated.

Robust Adaptive Control of Uncertain Nonlinear Systems in the Presence of Input Saturation and External Disturbance

2011-03-04

Changyun Wen , Jing Zhou , Zhitao Liu +1 more

In this technical note, we consider adaptive control of single input uncertain nonlinear systems in the presence of input saturation and unknown external disturbance. By using backstepping approaches, two new … In this technical note, we consider adaptive control of single input uncertain nonlinear systems in the presence of input saturation and unknown external disturbance. By using backstepping approaches, two new robust adaptive control algorithms are developed by introducing a well defined smooth function and using a Nussbaum function. The Nussbaum function is introduced to compensate for the nonlinear term arising from the input saturation. Unlike some existing control schemes for systems with input saturation, the developed controllers do not require assumptions on the uncertain parameters within a known compact set and a priori knowledge on the bound of the external disturbance. Besides showing global stability, transient performance is also established and can be adjusted by tuning certain design parameters.

Adaptive control of linearizable systems

1989-01-01

Shankar Sastry , Alberto Isidori

The authors give some initial results on the adaptive control of minimum-phase nonlinear systems which are exactly input-output linearizable by state feedback. Parameter adaptation is used as a technique to … The authors give some initial results on the adaptive control of minimum-phase nonlinear systems which are exactly input-output linearizable by state feedback. Parameter adaptation is used as a technique to make robust the exact cancellation of nonlinear terms, which is called for in the linearization technique. The application of the adaptive technique to control of robot manipulators is discussed. Only the continuous-time case is considered; extensions to the discrete-time and sampled-data cases are not obvious.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Adaptive motion control of rigid robots: A tutorial

1989-11-01

Roméo Ortega , Mark W. Spong

Continuous finite-time control for robotic manipulators with terminal sliding mode

2005-09-07

Shuanghe Yu , Xinghuo Yu , Bijan Shirinzadeh +1 more

A control engineer's guide to sliding mode control

1999-05-01

K.D. Young , Vadim Utkin , Ümi̇t Özgüner

Presents a guide to sliding mode control for practicing control engineers. It offers an accurate assessment of the so-called chattering phenomenon, catalogs implementable sliding mode control design solutions, and provides … Presents a guide to sliding mode control for practicing control engineers. It offers an accurate assessment of the so-called chattering phenomenon, catalogs implementable sliding mode control design solutions, and provides a frame of reference for future sliding mode control research.

The attitude control problem

1991-01-01

John T. Wen , Kenneth Kreutz-Delgado

A general framework for the analysis of the attitude tracking control problem for a rigid body is presented. A large family of globally stable control laws is obtained by using … A general framework for the analysis of the attitude tracking control problem for a rigid body is presented. A large family of globally stable control laws is obtained by using the globally nonsingular unit quaternion representation in a Lyapunov function candidate whose form is motivated by the consideration of the total energy of the rigid body. The controllers share the common structure of a proportional-derivative feedback plus some feedforward which can be zero (the model-independent case), the Coriolis torque compensation, or an adaptive compensation. These controller structures are compared in terms of the requirement on the a priori model information, guaranteed transient performance, and robustness. The global stability of the Luh-Walker-Paul robot end-effector controller is also analyzed in this framework.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Quadrotor Helicopter Flight Dynamics and Control: Theory and Experiment

2007-06-15

Gabriel Hoffmann , Haomiao Huang , Steven L. Waslander +1 more

Quadrotor helicopters are emerging as a popular platform for unmanned aerial vehicle (UAV) research, due to the simplicity of their construction and maintenance, their ability to hover, and their vertical … Quadrotor helicopters are emerging as a popular platform for unmanned aerial vehicle (UAV) research, due to the simplicity of their construction and maintenance, their ability to hover, and their vertical take o and landing (VTOL) capability. Current designs have often considered only nominal operating conditions for vehicle control design. This work seeks to address issues that arise when deviating significantly from the hover flight regime. Aided by well established research for helicopter flight control, three separate aerodynamic eects are investigated as they pertain to quadrotor flight, due to vehicular velocity, angle of attack, and airframe design. They cause moments that aect attitude control, and thrust variation that aects altitude control. Where possible, a theoretical development is first presented, and is then validated through both thrust test stand measurements and vehicle flight tests using the Stanford Testbed of Autonomous Rotorcraft for Multi-Agent Control (STARMAC) quadrotor helicopter. The results enabled improved controller performance.

Discrete-time variable structure control systems

1995-04-01

Wei-Bing Gao , Yufu Wang , A. Homaifa

This paper presents a treatment of discrete variable structure control systems. The purpose is to lay a foundation upon which design of such type of systems can be made properly. … This paper presents a treatment of discrete variable structure control systems. The purpose is to lay a foundation upon which design of such type of systems can be made properly. Phenomena of switching, reaching, and quasi-sliding mode are investigated thoroughly. Terms pertaining to discrete variable structure control are defined. A method of quasi-sliding mode design is given. The inherently existing quasi-sliding mode band is analyzed. A recently introduced "reaching law approach" is conveniently used to develop the control law for robust control. Comments are given regarding chattering. The design technique is illustrated by a simulated system.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Variable structure control of nonlinear systems: a new approach

1993-01-01

Wei-Bing Gao , J. C. Hung

A new approach for the design of variable structure control (VSC) of nonlinear systems is presented. It is based on a new method called the reaching law method, and is … A new approach for the design of variable structure control (VSC) of nonlinear systems is presented. It is based on a new method called the reaching law method, and is complemented by a sliding-mode equivalence technique. They facilitate the design of the system dynamics in all three modes of a VSC system including the sliding, reaching, and steady-state modes. Invariance and robustness properties are discussed. The approach is applied to a robot manipulator to demonstrate its effectiveness.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

PID vs LQ control techniques applied to an indoor micro quadrotor

2004-01-01

Samir Bouabdallah , A. Noth , Roland Siegwart

The development of miniature flying robots has become a reachable dream, thanks to the new sensing and actuating technologies. Micro VTOL systems represent a useful class of flying robots because … The development of miniature flying robots has become a reachable dream, thanks to the new sensing and actuating technologies. Micro VTOL systems represent a useful class of flying robots because of their strong abilities for small-area monitoring and building exploration. In this paper, we present the results of two model-based control techniques applied to an autonomous four-rotor micro helicopter called quadrotor. A classical approach (PID) assumed a simplified dynamics and a modern technique (LQ) based on a more complete model. Various simulations were performed and several tests on the bench validate the control laws. Finally, we present the results of the first test in flight with the helicopter released. These developments are part of the OS4 project in our lab.

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On characterizations of the input-to-state stability property

1995-04-01

Eduardo D. Sontag , Yüan Wang

Dynamic surface control for a class of nonlinear systems

2000-10-01

D. Swaroop , J. Karl Hedrick , Pak Yip +1 more

A method is proposed for designing controllers with arbitrarily small tracking error for uncertain, mismatched nonlinear systems in the strict feedback form. This method is another "synthetic input technique," similar … A method is proposed for designing controllers with arbitrarily small tracking error for uncertain, mismatched nonlinear systems in the strict feedback form. This method is another "synthetic input technique," similar to backstepping and multiple surface control methods, but with an important addition, /spl tau/-1 low pass filters are included in the design where /spl tau/ is the relative degree of the output to be controlled. It is shown that these low pass filters allow a design where the model is not differentiated, thus ending the complexity arising due to the "explosion of terms" that has made other methods difficult to implement in practice. The backstepping approach, while suffering from the problem of "explosion of terms" guarantees boundedness of tracking errors globally; however, the proposed approach, while being simpler to implement, can only guarantee boundedness of tracking error semiglobally, when the nonlinearities in the system are non-Lipschitz.

Command Filtered Backstepping

2009-05-27

Jay A. Farrell , Marios M. Polycarpou , M. K. Sharma +1 more

Implementation of backstepping becomes increasingly complex as the order of the system increases. This increasing complexity is mainly driven by the need to compute command derivatives at each step of … Implementation of backstepping becomes increasingly complex as the order of the system increases. This increasing complexity is mainly driven by the need to compute command derivatives at each step of the design, with the ultimate step requiring derivatives of the same order as the plant. This article addresses a modification that obviates the need to compute analytic derivatives by introducing command filters in the backstepping design. While the concept of the command filter has previously been introduced in the literature, the main contribution of this technical note is the rigorous analysis of the effect of the command filter on closed-loop stability and performance, and a proof of stability based on Tikhonov's theorem. The implementation approach includes a compensated tracking error that retains the standard stability properties of backstepping approaches.

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

2015-09-14

Wen‐Hua Chen , Jun Yang , Lei Guo +1 more

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 … 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.

Systematic design of adaptive controllers for feedback linearizable systems

1991-11-01

I. Kanellakopoulos , P.V. Kokotović , A. Stephen Morse

A systematic procedure is developed for the design of new adaptive regulation and trackdng schemes for a class of feedback linearizable nonlinear systems. The coordinate-free geometric conditions, which characterize this … A systematic procedure is developed for the design of new adaptive regulation and trackdng schemes for a class of feedback linearizable nonlinear systems. The coordinate-free geometric conditions, which characterize this class of systems, neither restrict the location of the unknown parameters, nor constrain the growth of the nonlinearities. Instead, they require that the nonlinear system be transformable into the so-called pure-feedback form. When this form is "strict", the proposed scheme guarantees global regulation and tracking properties, and substantially enlarges the class of nonlinear systems with unknown parameters for which global stabilization can be achieved. The main results of this paper use simple analytical tools, familiar to most control engineers.

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Output regulation of nonlinear systems

1990-01-01

Alberto Isidori , C.I. Byrnes

The problem of controlling a fixed nonlinear plant in order to have its output track (or reject) a family of reference (or disturbance) signal produced by some external generator is … The problem of controlling a fixed nonlinear plant in order to have its output track (or reject) a family of reference (or disturbance) signal produced by some external generator is discussed. It is shown that, under standard assumptions, this problem is solvable if and only if a certain nonlinear partial differential equation is solvable. Once a solution of this equation is available, a feedback law which solves the problem can easily be constructed. The theory developed incorporates previously published results established for linear systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">></ETX>

Adaptive prescribed-time trajectory tracking control for UVMS based on error transformation and adaptive prescribed-time filter

2025-06-25

Jingwei Yang , Haitao Liu , Xuehong Tian +2 more | Ocean Engineering

Fixed time controller for police quadcopter aircraft based on integral backstepping method

2025-06-25

Xiaolong Tian , Qi-Wei Sun , Nan Wang | Journal of Control Engineering and Applied Informatics

Model-free adaptive control of the combined aircraft with unknown multi-source disturbances and output saturation

2025-06-24

Lixin Liu , Han Xiao , Huijin Fan +2 more | Aerospace Science and Technology

Coupled-variable-based tracking control for state-constrained surface ships under external disturbance

2025-06-24

Nan Jiang , Zhongcai Zhang , Yang Gao +1 more | Ocean Engineering

Robust fractional-order sliding mode direct yaw moment control for lateral stabilization of FWID-EVs with time-delay and uncertainty

2025-06-24

Pak Kin Wong , Xingqi Hua , Jing Zhao | Proceedings of the Institution of Mechanical Engineers Part I Journal of Systems and Control Engineering

This paper presents a direct yaw moment control (DYC) strategy based on the fractional-order (FO) sliding mode control (SMC) algorithm to enhance the lateral stability of four-wheel independent drive electric … This paper presents a direct yaw moment control (DYC) strategy based on the fractional-order (FO) sliding mode control (SMC) algorithm to enhance the lateral stability of four-wheel independent drive electric vehicles (FWID-EVs) with uncertainty and time-delay. First, a two degrees of freedom (2-DOF) vehicle model with uncertainty and time-delay is developed. Based on the nonlinear vehicle model, a peaking-free disturbance observer is designed to mitigate the effect of unknown disturbance on the control system. Then, a robust adaptive nonsingular fast terminal FO sliding mode strategy for DYC is proposed. This strategy has the advantage of considering the key factors of SMC, not only ensuring the global convergence rate but also reducing the chattering problem. Moreover, this research thoroughly analyzes the benefits of introducing fractional operators in sliding mode surfaces or reaching laws. Finally, the proposed schemes are validated by a closed-loop simulation and a hardware-in-the-loop (HIL) test.

Constrained nonsingular predefined-time fault-tolerant control with prescribed performance for rigid spacecraft

2025-06-24

Meiling Tao , Wuhao Fang , Shengping Luo +1 more | Nonlinear Dynamics

Fault‐Tolerant Robust Fast Finite‐Time Path‐Following Control for Underactuated AUVs With Actuator Dynamics and Saturation

2025-06-23

MohammadReza Ebrahimpour , Mihai Lungu | Journal of Field Robotics

ABSTRACT This paper presents a nonlinear robust fast finite‐time controller for three‐dimensional (3D) path‐following of underactuated Autonomous Underwater Vehicles considering parametric uncertainties, external disturbances, and the actuator's dynamics, fault, and … ABSTRACT This paper presents a nonlinear robust fast finite‐time controller for three‐dimensional (3D) path‐following of underactuated Autonomous Underwater Vehicles considering parametric uncertainties, external disturbances, and the actuator's dynamics, fault, and saturation. A path‐following error system is built using the virtual guidance method. The proposed cascaded closed‐loop control scheme is composed of two layers: (1) first, a kinematic layer including an improved 3D approach‐angle–based guidance law employs the Lyapunov theory and a fast finite‐time backstepping control to transform the 3D path‐following position errors into the command velocities; (2) then, a kinetic layer is designed to compute the actual control inputs using an integral fast terminal sliding mode control and the Lyapunov theory. A nonlinear fast finite‐time disturbance observer enhances stability by estimating the lumped uncertainties in the sliding surface dynamics. A force/moment control loop equipped with a novel antiwindup system and a recursive least squares estimator compensates for the actuator's undesirable effects, including the internal dynamics, fault, and saturation. It is proved that the path‐following errors uniformly globally converge to zero within a finite time. Comparative simulations illustrate that the proposed control provides better dynamic response and robustness compared with the asymptotic and conventional finite‐time controllers.

Adaptive neural finite-time control for uncertain stochastic semi-Markov jump systems subject to actuator failures

2025-06-23

Baoping Jiang , Ruiping Xu , Zhen Liu +2 more | International Journal of Automation and Control

Horizontal control strategy of 3UPU/UP offshore parallel platform based on forward and inverse kinematic models

2025-06-23

Anqi Niu , Wei Wang , Weihan Qiu +2 more | Ocean Engineering

Geometric line-of-sight guidance law with exponential switching sliding mode control for marine vehicles’ path following

2025-06-23

Chengren Yuan , Changgeng Shuai , Zhanshuo Zhang +3 more | Frontiers in Robotics and AI

Marine vehicle guidance and control technology serves as the core support for advancing marine development and enabling scientific exploration. Its accuracy, autonomy, and environmental adaptability directly determine a vehicle’s mission … Marine vehicle guidance and control technology serves as the core support for advancing marine development and enabling scientific exploration. Its accuracy, autonomy, and environmental adaptability directly determine a vehicle’s mission effectiveness in complex marine environments. This paper explores path following for marine vehicles in the horizontal plane. To tackle the limitation of a fixed look-ahead distance, we develop a novel geometric line-of-sight guidance law. It adapts to diverse compound paths by dynamically adjusting according to cross-track errors and local path curvature. Then, to enhance control performance, we present an improved exponential switching law for sliding mode control, enabling rapid convergence, disturbance rejection, and chatter reduction. Additionally, integral sliding mode control is integrated to stabilize yaw angular velocity, ensuring the system’s global asymptotic stability. Through a series of numerical simulations, the effectiveness, robustness, and adaptability of our proposed methods are verified.

Nonlinear Optimal Control of the Aircraft’s Wing-Rock Effect Under a 5th-Order Model

2025-06-22

Gerasimos Rigatos , Mohamed Zribi , Zhiwei Gao +4 more | Aerotecnica Missili & Spazio

Design of Fixed-Time Tracking Control Scheme for the Perturbed Systems by Using Dynamic Surface Control and A New Disturbance-Observer

2025-06-21

Haipeng Su | Journal of Control Automation and Electrical Systems

Bounded integral control for uncertain ISS systems with convex input constraints

2025-06-21

George C. Konstantopoulos , Panos Papageorgiou , Charalampos P. Bechlioulis | Control Engineering Practice

Enhanced path following of underactuated ship by robust adaptive model predictive control and variable LOS guidance

2025-06-21

Shihang Gao , Xianku Zhang , Hugan Zhang | Ships and Offshore Structures

Disturbance Estimator-based Predefined-time Adaptive Fuzzy Attitude Control for Multiple UAVs

2025-06-20

Muxuan Li , Huanqing Wang | Nonlinear Dynamics

Robust control strategies in task space for uncertain dynamical systems with input saturation

2025-06-20

Chunsheng He , Mianhao Wang , Ke Shao +3 more | Nonlinear Dynamics

Fixed-time tracking control for fractional-order uncertain parametric nonlinear systems with input delay: A command filter-based neuroadaptive control method

2025-06-20

Xiyu Zhang , Chun Feng , Youjun Zhou +1 more | Chaos Solitons & Fractals

Event-triggered adaptive fault-tolerant auto-berthing control of underactuated vessels with predefined performance

2025-06-20

Chun Li , Guibing Zhu , Qiang Zhang | Ships and Offshore Structures

Robust Control for Uncertain Vertical Electric Stabilization System With Flexible Nonlinearity Using Backstepping Idea

2025-06-20

Peng Liu , Tan Lu , He Zhang | International journal of mechanical system dynamics

ABSTRACT A robust control method for the uncertain vertical electric stabilization system (VESS) with flexible nonlinearity is proposed, and the mismatched uncertainty is considered and compensated based on the backstepping … ABSTRACT A robust control method for the uncertain vertical electric stabilization system (VESS) with flexible nonlinearity is proposed, and the mismatched uncertainty is considered and compensated based on the backstepping idea. First, based on evaluating the coupling effects of the flexible nonlinearity, the analytical dynamics model of the VESS is established. Second, the tracking error is defined as the evaluation of the system's pitch‐pointing tracking control, and then the mismatched state space model with two interconnected subsystems is established as the controlled system. Third, the original mismatched system is converted to the locally matched system using the backstepping design to transform the system state variables. The robust control is proposed to handle the flexible nonlinearity and mismatched uncertainty, which can make both the original system and the reconfigured system present practical stability. Finally, the effectiveness of the proposed control is verified by numerical simulation experiments. This study should be the first to consider flexible nonlinearity coupling and two different uncertainties (matched and mismatched uncertainty) in the design of pitch‐pointing tracking control for the vertical electric stabilization system (VESS).

Comprehensive analysis of nonlinear control strategies in trajectory tracking of Crazyflie Quadrotor

2025-06-20

Osama H. Zekry , Mahmoud Ashry , Ahmed T. Hafez +1 more | CEAS Aeronautical Journal

A novel ship-mounted rope-based cleaning mechanism: Dynamic modeling and sliding mode controller design

2025-06-20

Jian Li , Guangdong Han , Shuting Lei +4 more | Proceedings of the Institution of Mechanical Engineers Part K Journal of Multi-body Dynamics

The cleaning of cargo holds on ships typically requires extensive manual labor, resulting in inefficient operations and elevated risk factors. To address these challenges, this study proposes the utilization of … The cleaning of cargo holds on ships typically requires extensive manual labor, resulting in inefficient operations and elevated risk factors. To address these challenges, this study proposes the utilization of rope-driven parallel mechanisms (RDPMs) as an innovative solution for automated cleaning. Additionally, a novel rope-based cleaning mechanism (R-BCM) is introduced, and its kinematic model is derived using robotics principles. Recognizing the challenges associated with accurately gauging ship attitude in marine environments, a dynamic model of separated disturbance is established. To improve tracking accuracy, shorten response time, and reduce power consumption, an adaptive sliding mode control with an improved exponential reaching law (IER-SMC) is proposed. The stability of this system is rigorously analyzed. Numerical simulations are conducted to evaluate the control performance of the system, particularly under conditions of ship movement and external disturbances. The simulation results show that, compared to the sliding mode control with a traditional exponential reaching law (TER-SMC), IER-SMC improves convergence speed by 51.0%, reduces steady-state error by 64.7%, and decreases energy consumption by 1.05%. Furthermore, the R-BCM prototype is developed, and cleaning simulation experiments are conducted. The experimental results show that, compared to TER-SMC, IER-SMC improves convergence speed by 44.4%, reduces steady-state error by 22.3%, and decreases energy consumption by 10.8%. Moreover, after a single cleaning operation, the applied mud and sand mixture is almost completely removed. These findings underscore the effectiveness of the IER-SMC in achieving rapid convergence, low power consumption, and precise tracking, making it a promising approach for enhancing the efficiency and safety of cargo hold cleaning operations on ships.

Predefined-time fuzzy adaptive decentralized control for interconnected systems against multiple input signal constraints

2025-06-19

Libin Wang , Zeyu Han , Wei Wang | Nonlinear Dynamics

Prescribed-time semi-global output feedback stabilization by a time-varying high-gain observer

2025-06-19

Shunli Li , Bin Zhou , Guang‐Ren Duan +1 more | Automatica

A Convex Constraint Approach for High-Type Control Loop Design

2025-06-19

Chao Liu , Xiaoxia Qiu , Yao Mao | Electronics

This paper proposes a high-type control loop design method for LQR-LMI based on Lyapunov and polyhedral model theory. The high-type control loop design problem is simplified into a convex constraint … This paper proposes a high-type control loop design method for LQR-LMI based on Lyapunov and polyhedral model theory. The high-type control loop design problem is simplified into a convex constraint problem, which achieves superior tracking performance. In this framework, the input amplitude of the control signal, the poles of the closed-loop system, the suppression of external interference and the perturbation of internal parameters are considered, and the linear matrix inequality (LMI) method is effectively used to solve the problems. In this paper, the polyhedral model control theory is introduced to characterize the uncertainty of the system for the change of model parameters of the controlled plant. Aiming at the problem of external disturbance suppression, the H2/H∞ control method is introduced into the system. These control methods provide the basis for the design of the high-type control loop. Compared with the simulation results of other optimization algorithms, the effectiveness and superiority of the controller parameter tuning rules in the proposed high-type control loop are verified.

Adaptive Predefined‐Time Stabilization for A Class of Nonlinear Time‐Delay Systems With Input Unmodeled Dynamics

2025-06-19

Qiang Li , Ronghao Wang , Jun Mao +1 more | International Journal of Adaptive Control and Signal Processing

ABSTRACT In this paper, a predefined‐time control scheme, which intends to stabilize the concerned nonlinear time‐delay systems possessing input unmodeled dynamics, is developed. During the controller design procedure, a predefined‐time … ABSTRACT In this paper, a predefined‐time control scheme, which intends to stabilize the concerned nonlinear time‐delay systems possessing input unmodeled dynamics, is developed. During the controller design procedure, a predefined‐time controller exported by following the backstepping technique is applied to the stabilizer of such concerned system, and the Lyapunov‐Krasovskii functionals (LKFs), M‐filter are respectively introduced to deal with the time delays and input unmodeled dynamics. Meanwhile, the fractional power piecewise function is constructed in the stabilizer to avoid the singularity problem caused by differentiating the virtual control laws at the origin. In addition, the neural networks are introduced to deal with the apparent nonlinearities by basing on their approximation ability. In stability analysis, under the proper selection of Lyapunov function candidates(LFC), we can verify that all signals in the formulating closed‐loop system can possess the property of semi‐global uniformly ultimately bounded (SGUUB) within a given predefined‐time, and simulations, which cover theoretical and practical simulations, can reflect the availability of the developed scheme.

Reinforcement learning-based tracking control of AUV with input saturation in complex environments

2025-06-19

Xiangxiang Liu , Bing Sun , Zinan Su | Ships and Offshore Structures

Finite-time attitude tracking control for spacecraft based on backstepping method with input saturation

2025-06-18

Yanmin Ren , Aijia Xing | PLoS ONE

In this paper, the finite-time attitude tracking control problem for spacecraft based on the backstepping method is addressed. Firstly, a finite-time controller is designed, which can provide robustness for external … In this paper, the finite-time attitude tracking control problem for spacecraft based on the backstepping method is addressed. Firstly, a finite-time controller is designed, which can provide robustness for external disturbance by employing an improved adaptation law. Secondly, a novel finite-time controller with input saturation is proposed by introducing the hyperbolic function and auxiliary system to guarantee the control torques below a predetermined value. The above two controllers are continuous, thus, they are chattering-free. Finally, simulation results are presented to illustrate the effectiveness of the control strategies.

Design of a Saturated Filtered High Gain Observer for a Class of Disturbed Nonlinear Systems

2025-06-18

M. Farza , Oumaima Chehaibi , Salim Hadj Saïd +1 more | International Journal of Robust and Nonlinear Control

ABSTRACT This paper provides a redesigned version of the Standard High Gain Observer (SHGO) allowing to significantly reduce its underlying peaking phenomenon while improving its sensitivity to noise measurements. The … ABSTRACT This paper provides a redesigned version of the Standard High Gain Observer (SHGO) allowing to significantly reduce its underlying peaking phenomenon while improving its sensitivity to noise measurements. The redesign of the SHGO is performed in two steps respectively leading to a Filtered High Gain Observer (FHGO) and a Saturated Filtered High Gain Observer (SATFHGO). The FHGO is obtained by incorporating a suitable filtering process into the SHGO design reducing thereby its sensitivity to noise measurements. This is simply achieved by adding to the SHGO a linear filter of an arbitrary order whose input is the SHGO output observation error which is substituted by the filter output in the SHGO equation. Of fundamental interest, a suitable analysis of the steady‐state response of the FHGO shows that it performs better in the presence of high‐frequency signal measurements. The SATFHGO is obtained by substituting the components of the correction term in the FHGO by appropriate nested saturation functions leading thereby to a free peaking observer. A systematic procedure is proposed to compute the gain of the SATFHGO. The effectiveness of the proposed SATFHGO is highlighted through probing simulation results involving a single link robot arm system.

Tracking Control and Experiment for Propeller‐Driven Wall‐Climbing Robot Considering Actuator Dynamics and Saturation

2025-06-18

Yang Sun , Yong Guo , Aijun Li | Journal of Field Robotics

ABSTRACT In this paper, an adaptive tracking controller for the propeller‐driven wall‐climbing robot is developed, which is subject to velocity‐related input saturation and velocity constraint. First, the model of the … ABSTRACT In this paper, an adaptive tracking controller for the propeller‐driven wall‐climbing robot is developed, which is subject to velocity‐related input saturation and velocity constraint. First, the model of the propeller‐driven wall‐climbing robot is established, where actuator dynamics and input saturation are considered with velocity constraints. The strategy of active gravity balance is put forward, which simplifies the modeling but leads to the problem of velocity‐related input saturation. Second, the Gauss integration function is used to approximate the velocity‐related input saturation. The velocity constraint would be handled by employing the barrier Lyapunov‐based transformation rather than the barrier Lyapunov function (BLF) method. Thirdly, the tracking controller is developed based on the dynamic surface control method, where the adaptive robust controller and neural networks are combined to deal with unmodeled dynamics and external disturbances. According to the Lyapunov stability theory, it is proved that the propeller‐driven robot system will be stable under the developed controller, while signals in the closed‐loop system are ultimately uniformly bounded. Finally, simulation results show the effectiveness of the proposed tracking control scheme.

Adaptive Fixed-Time NN-Based Tracking Control for a Type of Stochastic Nonlinear Systems Subject to Input Saturation

2025-06-18

Daohong Zhu , Zhenzhen Long , Liandi Fang | Mathematics

This paper considers the adaptive fixed-time tracking control problem for stochastic systems subject to input saturation. Firstly, a smooth function approximation method is utilized to eliminate the effect of input … This paper considers the adaptive fixed-time tracking control problem for stochastic systems subject to input saturation. Firstly, a smooth function approximation method is utilized to eliminate the effect of input saturation. Then, by combining the neural networks (NNs) approximation method with the backstepping-like technique, an adaptive fixed-time tracking control scheme is explicitly developed. The proposed scheme can ensure that the state variables are bounded in probability and the tracking error converges to a small region of the equilibrium point in a fixed time. Eventually, two numerical examples are given to indicate the performance and effectiveness of the presented strategy.

Recurrent Neuroadaptive Output Feedback Control of Motor Servo Systems With Disturbance Compensation

2025-06-18

Bofan Li , Guichao Yang | International Journal of Robust and Nonlinear Control

ABSTRACT A recurrent neuroadaptive output feedback controller which combines recurrent neural network (RNN) and extended state observer (ESO) will be proposed for motor servo systems with model uncertainties and signal … ABSTRACT A recurrent neuroadaptive output feedback controller which combines recurrent neural network (RNN) and extended state observer (ESO) will be proposed for motor servo systems with model uncertainties and signal noises. Notably, RNN can accurately approximate endogenous uncertainties. However, under strong external disturbances, its approximation performance may deteriorate and even instability may happen. Therefore, the controller in this paper will be proposed to handle these control issues. Simulation and experimental results demonstrate the effectiveness of the proposed controller.

An Improved Discrete‐Time Super‐Twisting Control Algorithm With Double‐Power Reaching Law

2025-06-18

Yang Liu , Hanpu Zhao , Mingxing Li +1 more | International Journal of Robust and Nonlinear Control

ABSTRACT Compared with traditional sliding mode control, the super‐twisting control algorithm not only exhibits disturbance rejection performance but also has the ability to suppress system chattering. However, for the sampling … ABSTRACT Compared with traditional sliding mode control, the super‐twisting control algorithm not only exhibits disturbance rejection performance but also has the ability to suppress system chattering. However, for the sampling control system, while the discrete‐time super‐twisting control algorithm still exhibits favorable control effects, it inevitably results in larger system chattering. To address these limitations, this paper proposes an improved discrete‐time double‐power super‐twisting control algorithm (DDSTA). By introducing the double‐power term, the convergence performance of the system is improved, and the chattering of the system is reduced using the boundary layer approach. Starting with an undisturbed first‐order continuous system, we establish that the trajectory under DDSTA converges within a bounded region around the origin. We further examine the stability of the perturbed continuous system using a geometric method. Finally, experimental studies on the gantry manipulator system are presented to demonstrate the effectiveness of the proposed methods.

Event-triggered nonsingular fast terminal sliding mode control for attitude synchronization of multiple spacecraft

2025-06-18

Syed Muhammad Amrr | Journal of Vibration and Control

This paper presents a robust control strategy for achieving synchronized and accurate attitude tracking of multiple spacecraft in the presence of uncertainties, communication constraints, and input saturation. A new controller … This paper presents a robust control strategy for achieving synchronized and accurate attitude tracking of multiple spacecraft in the presence of uncertainties, communication constraints, and input saturation. A new controller is proposed that combines a nonsingular fast terminal sliding mode control (NSFTSMC) with a dynamic event-triggered (ET) mechanism. The NSFTSMC ensures robustness against exogenous disturbances, while the ET strategy mitigates the effects of limited communication bandwidth by reducing the control update frequency. The ET method implements an aperiodic control update approach, that is, the actuator output gets updated only when a predefined triggering condition is satisfied. Until then, the actuator output maintains its previous output. Lyapunov stability analysis confirms that the proposed composite controller guarantees practical finite-time convergence of all error states to a small neighborhood around the origin. Moreover, the non-existence of Zeno behavior under the proposed ET scheme is also demonstrated theoretically. Finally, the effectiveness of the proposed control method is demonstrated through comparative simulations with recent ET-based schemes. Simulation results across various performance metrics highlight the superiority of the proposed approach.

Particle swarm optimized fuzzy extended state observer design for disturbance rejection in sliding mode attitude control of a quadrotor

2025-06-18

Dipanjan Konar , Amitava Chatterjee | Engineering Applications of Artificial Intelligence

Cooperative trajectory tracking control of USV-UAV with non-singular sliding mode surface and RBF neural network

2025-06-18

Wenyu Xu , Xianku Zhang , Zhiwei Miao | Ocean Engineering

Dynamic event-triggered predefined-time adaptive attitude fault-tolerant control for uncertain unmanned aerial vehicles with disturbances and actuator faults

2025-06-18

G. Guo , Shaoqiu Xiao , Fuchang Chen +2 more | Aerospace Science and Technology

Reduced-order adaptive observer for rectangular descriptor systems with incremental quadratic constraints

2025-06-17

Meenakshi Tripathi , Lazaros Moysis , Mahendra Kumar Gupta +1 more | International Journal of Systems Science

Distributed adaptive stabilization for stochastic nonlinear systems with unknown boundaries: a novel fixed-time stability in probability

2025-06-17

Jiahui Zhu , Liping Xie , Kanjian Zhang | Nonlinear Dynamics

Sliding Mode Control for Stochastic SIR Models with Telegraph and Lévy Noise: Theory and Applications

2025-06-17

Lu Liu , Yi Zhang , Yufeng Tian +2 more | Symmetry

This paper establishes a new stochastic SIR epidemic model that incorporates telegraph noise and Lévy noise to simulate the complex environmental disturbances affecting disease transmission. Given the susceptibility of epidemic … This paper establishes a new stochastic SIR epidemic model that incorporates telegraph noise and Lévy noise to simulate the complex environmental disturbances affecting disease transmission. Given the susceptibility of epidemic spread to environmental noise and its intricate dynamics, an adaptive sliding mode controller based on an integral sliding surface and an adaptive control law is proposed. This controller is capable of stabilizing the constructed model and effectively suppressing the spread of the disease. The main contributions of this paper include the following: establishing a comprehensive and realistic stochastic SIR model that accounts for the complex impacts of telegraph noise (symbolizing periodic environmental changes) and Lévy noise (representing sudden environmental shocks) on the dynamics of disease transmission; employing T-S fuzzy modeling, which considers the design of fuzzy rules and the symmetry of membership functions, to ensure linearization of the model; constructing an integral sliding surface and designing an adaptive sliding mode controller for the fuzzy-processed model. Finally, the effectiveness of the proposed control method is validated through numerical simulations.

Robust Constraint-Following Control Strategy for Industrial Quadrotor UAV Subjected to Time-Varying Uncertainties

2025-06-16

Siyang Yang , Yiqing Huang , Wengang Zhang | Arabian Journal for Science and Engineering

Adaptive quantized prescribed performance control for uncertain nonlinear systems with full error constraints under event-triggered scheme

2025-06-16

Hang Su , Qiang Zhang , Cheng Tan | Nonlinear Dynamics

Adjustable predefined time sliding mode control method for nonlinear systems with unknown disturbances

2025-06-16

Xiaohua Liu , Chao Jia , Jing Ping | Chaos Solitons & Fractals

3-D trajectory tracking of a harvesting robot using composite control based on model prediction and disturbance adaptive rejection

2025-06-14

Changbin Wang , Dalei Song , Chong Li +1 more | Ocean Engineering

Adaptive gain sliding mode control for uncertain nonlinear systems using barrier-like functions

2025-06-13

Xiaoxue Zhang , Huifang Kong , Zhihong Man | Nonlinear Dynamics

Abstract Uncertain nonlinear systems often face challenges such as unmodeled dynamics and disturbances, which can degrade control performance and robustness. Traditional sliding mode controllers with constant gains may suffer from … Abstract Uncertain nonlinear systems often face challenges such as unmodeled dynamics and disturbances, which can degrade control performance and robustness. Traditional sliding mode controllers with constant gains may suffer from excessive chattering or fixed response rates, while existing adaptive methods often entail intricate theoretical analysis or mathematical computations. To address these limitations, this paper proposes a novel adaptive gain sliding mode controller (AGSMC) that integrates a barrier-like function (BLF) with a BLF-based disturbance observer for a class of uncertain nonlinear systems. The BLF is first defined and applied to design the control gain, while the BLF-based disturbance observer dynamically updates this gain to relax the need for prior knowledge of disturbance bounds. Compared to the constant-gain sliding mode control, the proposed AGSMC enhances response speed, robustness, and significantly reduces chattering in the control law during the sliding phase. The system's stability under the AGSMC framework is rigorously proved by the Lyapunov stability theorem. Numerical simulations demonstrate the effectiveness of the proposed method, showing superior performance over the traditional sliding mode controller and two other adaptive sliding mode controllers.

URED Observer-based Feedback Linearized Neuro Adaptive SMC for a Twin Rotor MIMO System: Design and Experimental Study

2025-06-13

Saqib Irfan , Liangyu Zhao , Usman Javaid +1 more | Guidance Navigation and Control

Nonlinear dynamic analysis of non-autonomous angular velocity systems for 2-DOF aerial manipulators

2025-06-13

Xitong Guo , Pingjuan Niu , Guoyuan Qi +2 more | Nonlinear Dynamics

Reliability-based robust event-triggered anti-windup control for Arctic dynamic positioning of turret-moored vessels under ice loads

2025-06-13

Shasha Wang , B. Tan , Yuanhui Wang +2 more | Ocean Engineering

A NEW SLIDING MODE CONTROLLER IMPLEMENTATION ON AN AUTONOMOUS QUADCOPTER SYSTEM

2019-06-01

Jayson Piquero , Vincent Kyle Delica , Alfred Loue F. Orquia +7 more

This paper introduces Sliding Mode controller, a non-linear controller, for the implementation of an autonomous quadrotor platform, a non-linear system. The Sliding Mode controller was applied to a PixHawk Flight … This paper introduces Sliding Mode controller, a non-linear controller, for the implementation of an autonomous quadrotor platform, a non-linear system. The Sliding Mode controller was applied to a PixHawk Flight Controller using the Ardupilot firmware. The simulation testing using SITL shows the effectiveness of the controller before flight. The results imply the improvement when using Sliding Mode Control in comparison to PID controller. The results show that there is a reduction in attitude error when using Sliding Mode Control in comparison with PID control in all simulation and actual hardware results. The robustness of Sliding Mode Control was also tested by adding parameter uncertainties and disturbances to the system. In this study, the root-mean-square error obtained in the Sliding Mode Control is 1.546580%, 0.634243%, and 13.466256% for the roll, pitch, and yaw movements respectively, and the root-mean-square error obtained in the PID control is 2.588324%, 4.553838%, and 18.860183% for the roll, pitch, and yaw movements respectively. This shows that the quadrotor using Sliding Mode Control is less prone to attitude errors.