2,356 research outputs found
Adaptive Dual Layer Super-Twisting Control and Observation
This is the author accepted manuscript. The final version is available from Taylor & Francis via the DOI in this record.In this paper a super-twisting-like structure with adaptive gains is proposed. The structure is parameterized by two scalar gains, both of which adapt, and by an additional time-varying term. The magnitudes of the adaptive terms are allowed to both increase and decrease as appropriate so that they are as small as possible, in the sense that they do not unnecessarily over-bound the uncertainty, and yet are large enough to sustain a sliding motion. In the paper, a new time varying gain is incorporated into the traditional super-twisting architecture. The proposed adaption law has a dual-layer structure which is formally analyzed using Lyapunov techniques. The additional term has the effect of simplifying the stability analysis whilst guaranteeing the second order sliding mode properties of the traditional super-twisting schem
Adaptive continuous higher order sliding mode control
Author's Preprint, submitted to AutomaticaAn early version of this paper was presented at ACC’14.This paper is concerned with the development of an adaptation structure which can be applied to conventional, super-twisting and
higher-order sliding mode schemes. The objective is to alter the modulation gains associated with these schemes in such a way
that they are as small as possible to mitigate chattering effects, but large enough to ensure that sliding can be maintained in the
presence of bounded and derivative bounded uncertainties. In all the proposed schemes, the equivalent control is used to drive
the adaptive mechanism. The approach is based on a novel dual layer nested adaptive methodology which is quite different to the
existing schemes proposed in the sliding mode literature. The new adaptive schemes do not require knowledge of the minimum and
maximum allowed values of the ad
Continuous higher order sliding mode control with adaptation of air breathing hypersonic missile
This is the peer reviewed version of the following article: Yu, P., Shtessel, Y., and Edwards, C. (2016) Continuous higher order sliding mode control with adaptation of air breathing hypersonic missile. International Journal of Adaptive Control and Signal Processing, which has been published in final form at 10.1002/acs.2664. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving: http://olabout.wiley.com/WileyCDA/Section/id-820227.html#terms}Hypersonic missile control in the terminal phase is addressed using continuous higher order sliding mode (AHOSM) control with adaptation. The AHOSM self-tuning controller is proposed and studied. The double-layer adaptive algorithm is based on equivalent control concepts and ensures non-overestimation of the control gain to help mitigates control chattering. The proposed continuous AHOSM control is validated via simulations of a hypersonic missile in the terminal phase. The robustness and high accuracy output tracking in the presence of matched and unmatched external disturbances and missile model uncertainties is demonstrate
Enhanced Continuous Higher Order Sliding Mode Control with Adaptation
This is the author accepted manuscript. The final version is availabel from Elsevier via the DOI in this recordThis paper proposes a new Continuous Adaptive HOSM control algorithm. The key
advantage of the adaption scheme is that it does not require knowledge of the bounds on
the matched uncertainty, and the gains themselves are not conservatively overestimated
by the adaption scheme – which helps mitigate the problem of chattering. Compared
with earlier work, two variable parameters are allowed to adapt and this facilitates
much better self-tuning capabilities and improved closed-loop performance
Review of sliding mode control application in autonomous underwater vehicles
973-984This paper presents a review of sliding mode control for autonomous underwater vehicles (AUVs). The AUVs are used under water operating in the presence of uncertainties (due to hydrodynamics coefficients) and external disturbances (due to water currents, waves, etc.). Sliding mode controller is one of the nonlinear robust controllers which is robust towards uncertainties, parameter variations and external disturbances. The evolution of sliding mode control in motion control studies of autonomous underwater vehicles is summarized throughout for the last three decades. The performance of the controller is examined based on the chattering reduction, accuracy (steady state error reduction), and robustness against perturbation. The review on sliding mode control for AUVs provides insights for readers to design new techniques and algorithms, to enhance the existing family of sliding mode control strategies into a new one or to merge and re-supervise the control techniques with other control strategies, in which, the aim is to obtain good controller design for AUVs in terms of great performance, stability and robustness
On Continuous Full-Order Integral-Terminal Sliding Mode Control with Unknown Apriori Bound on Uncertainty
This study aims at providing a solution to the problem of designing a
continuous and finite-time control for a class of nonlinear systems in the
presence of matched uncertainty with an unknown apriori bound. First, we
propose a Full-Order Integral-Terminal Sliding Manifold (FOITSM) with a
conventional (discontinuous) sliding mode to show that it provides the combined
attributes of the nonsingular terminal and integral sliding mode algorithms.
Secondly, an Adaptive Disturbance Observer (ADO) has been designed to alleviate
the effect of the uncertainty acting on the system. On application of the
ADO-based Full-Order Integral-Terminal Sliding Mode Control (FOITSMC), the
chattering phenomenon in control input has been reduced substantially in the
presence of conditionally known matched disturbances. Moreover, the adaptive
gains of ADO are updated non-monotonically without over-bounding the acting
disturbance, yet sustain the global boundedness of state trajectories within a
specific bound. %Finally, an application of the proposed algorithm for attitude
stabilization of a rigid spacecraft has been successively shown.Comment: 14 pages, 9 figure
State Estimation For An Agonistic‐Antagonistic Muscle System
Research on assistive technology, rehabilitation, and prosthetics requires the understanding of human machine interaction, in which human muscular properties play a pivotal role. This paper studies a nonlinear agonistic‐antagonistic muscle system based on the Hill muscle model. To investigate the characteristics of the muscle model, the problem of estimating the state variables and activation signals of the dual muscle system is considered. In this work, parameter uncertainty and unknown inputs are taken into account for the estimation problem. Three observers are presented: a high gain observer, a sliding mode observer, and an adaptive sliding mode observer. Theoretical analysis shows the convergence of the three observers. Numerical simulations reveal that the three observers are comparable and provide reliable estimates
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