scholarly journals Terminal Sliding Mode Control with Adaptive Law for Uncertain Nonlinear System

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Zhanshan Zhao ◽  
Jing Zhang ◽  
Liankun Sun ◽  
Dakun Zhang
Keyword(s):  
Nonlinear System ◽  
Sliding Mode ◽  
Second Order ◽  
System Stability ◽  
Order System ◽  
Unmodeled Dynamics ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Adaptive Law ◽  
Nonsingular Terminal Sliding Mode

A novel nonsingular terminal sliding mode controller is proposed for a second-order system with unmodeled dynamics uncertainties and external disturbances. We need not achieve the knowledge for boundaries of uncertainties and external disturbances in advance. The adaptive control gains are obtained to estimate the uncertain parameters and external disturbances which are unknown but bounded. The closed loop system stability is ensured with robustness and adaptation by the Lyapunov stability theorem in finite time. An illustrative example of second-order nonlinear system with unmodeled dynamics and external disturbances is given to demonstrate the effectiveness of the presented scheme.

scholarly journals Chebyshev Neural Network-Based Adaptive Nonsingular Terminal Sliding Mode Control for Hypersonic Vehicles

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Ruimin Zhang ◽  
Qiaoyu Chen ◽  
Haigang Guo
Keyword(s):  
Sliding Mode Control ◽  
Attitude Control ◽  
Sliding Mode ◽  
Hypersonic Vehicle ◽  
Parameter Uncertainties ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Adaptive Law ◽  
Nonsingular Terminal Sliding Mode

This paper presents an adaptive nonsingular terminal sliding mode control approach for the attitude control of a hypersonic vehicle with parameter uncertainties and external disturbances based on Chebyshev neural networks (CNNs). First, a new nonsingular terminal sliding surface is proposed for a general uncertain nonlinear system. Then, a nonsingular sliding mode control is designed to achieve finite-time tracking control. Furthermore, to relax the requirement for the upper bound of the lumped uncertainty including parameter uncertainties and external disturbances, a CNN is used to estimate the lumped uncertainty. The network weights are updated by the adaptive law derived from the Lyapunov theorem. Meanwhile, a low-pass filter-based modification is added into the adaptive law to achieve fast and low-frequency adaptation when using high-gain learning rates. Finally, the proposed approach is applied to the attitude control of the hypersonic vehicle and simulation results illustrate its effectiveness.

Smooth second-order nonsingular terminal sliding mode control for reusable launch vehicles

2014 ◽  
Vol 7 (1) ◽  
pp. 95-110 ◽  
Author(s):  
Shaobo Ni ◽  
Jiayuan Shan
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Tracking Error ◽  
Second Order ◽  
Convergence Time ◽  
Control Input ◽  
Terminal Sliding Mode ◽  
Content Type ◽  
Nonsingular Terminal Sliding Mode ◽  
Attitude Tracking

Purpose – The purpose of this paper is to present a sliding mode attitude controller for reusable launch vehicle (RLV) which is nonlinear, coupling, and includes uncertain parameters and external disturbances. Design/methodology/approach – A smooth second-order nonsingular terminal sliding mode (NTSM) controller is proposed for RLV in reentry phase. First, a NTSM manifold is proposed for finite-time convergence. Then a smooth second sliding mode controller is designed to establish the sliding mode. An observer is utilized to estimate the lumped disturbance and the estimation result is used for feedforward compensation in the controller. Findings – It is mathematically proved that the proposed sliding mode technique makes the attitude tracking errors converge to zero in finite time and the convergence time is estimated. Simulations are made for RLV through the assumption that aerodynamic parameters and atmospheric density are perturbed. Simulation results demonstrate that the proposed control strategy is effective, leading to promising performance and robustness. Originality/value – By the proposed controller, the second-order sliding mode is established. The attitude tracking error converges to zero in a finite time. Meanwhile, the chattering is alleviated and a smooth control input is obtained.

A novel adaptive second-order nonsingular terminal sliding mode guidance law design

2020 ◽  
Vol 234 (16) ◽  
pp. 2263-2273
Author(s):  
Shuai Xu ◽  
Min Gao ◽  
Dan Fang ◽  
Yi Wang ◽  
Baochen Li
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Initial Conditions ◽  
Dynamic Control ◽  
Small Neighborhood ◽  
Lyapunov Stability Theory ◽  
Second Order ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Nonsingular Terminal Sliding Mode

Aiming at the problem of missile attacking ground target in pitch plane, combined with a composite fast nonsingular terminal sliding mode, a new adaptive finite-time stable guidance law with attack angle constraint is designed based on the second-order sliding mode control. The improved extended state observer is used to estimate the uncertainties and compensate the control quantity, and the dynamic control gains are designed to avoid the problem about “excessive estimation” of the parameter upper limit. According to the Lyapunov stability theory, it is proved that the system states can converge into a small neighborhood near the equilibrium point in a finite time. Monte Carlo simulation is carried out by randomly generating initial conditions, which proves that the guidance law has strong adaptability to different initial conditions and has good guidance precision.

Finite-time attitude tracking control of air bearing table for spacecraft rendezvous and docking

2016 ◽  
Vol 232 (1) ◽  
pp. 96-110 ◽  
Author(s):  
Cheng Huang ◽  
Yan Wang ◽  
Xing-lin Chen
Keyword(s):  
Finite Time ◽  
Tracking Control ◽  
Sliding Mode ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Finite Time Stability ◽  
Nonsingular Terminal Sliding Mode ◽  
Attitude Tracking ◽  
Attitude Tracking Control ◽  
Rendezvous And Docking

This paper studies the problem of attitude tracking control for spacecraft rendezvous and docking based on a physical ground simulation system. Two finite-time controllers based on quaternion are proposed by using a novel fast nonsingular terminal sliding mode surface associated with the adaptive control, the novel fast nonsingular terminal sliding mode surface not only contains the advantages of the fast nonsingular terminal sliding mode surface, but also can eliminate unwinding caused by the quaternion. The first controller, which is continuous and chattering-free, can compensate unknown constant external disturbances, while the second controller can both compensate parametric uncertainties and varying external disturbances with unknown bounds without chattering. Lyapunov theoretical analysis and simulation results show that the two controllers can make the closed-loop system errors converge to zero in finite time and guarantee the finite-time stability of the system.

Continuous adaptive finite-time modified function projective lag synchronization of uncertain hyperchaotic systems

2016 ◽  
Vol 40 (3) ◽  
pp. 853-860 ◽  
Author(s):  
Xuan-Toa Tran ◽  
Hee-Jun Kang
Keyword(s):  
Finite Time ◽  
Control Method ◽  
Sliding Mode ◽  
External Disturbances ◽  
Lag Synchronization ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode ◽  
Projective Lag Synchronization ◽  
Twisting Algorithm ◽  
Hyperchaotic Systems

This paper introduces an adaptive control method for finite-time modified function projective lag synchronization of uncertain hyperchaotic systems. Based upon novel nonsingular terminal sliding mode surfaces and the adaptive super-twisting algorithm, a controller is proposed to provide robustness, high precision and fast and finite-time modified function projective lag synchronization without the knowledge of the upper bound of uncertainties and unknown external disturbances. In addition, chattering is significantly attenuated due to the inherited continuity of the proposed controller. The global stability and finite-time convergence are rigorously proven. Numerical simulation is presented to demonstrate the effectiveness and feasibility of the proposed strategy and to verify the theoretical results.

A New Nonsingular Terminal Sliding Mode Control for Rigid Spacecraft Attitude Tracking

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Zeng Wang ◽  
Yuxin Su ◽  
Liyin Zhang
Keyword(s):  
Equilibrium Point ◽  
Finite Time ◽  
Sliding Mode ◽  
Tracking Errors ◽  
Robust Controller ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode ◽  
Attitude Tracking ◽  
Rigid Spacecraft

This paper addresses the finite time attitude tracking for rigid spacecraft with inertia uncertainties and external disturbances. First, a new nonsingular terminal sliding mode (NTSM) surface is proposed for singularity elimination. Second, a robust controller based on NTSM is designed to solve the attitude tracking problem. It is proved that the new NTSM can converge to zero within finite time, and the attitude tracking errors converge to an arbitrary small bound centered on equilibrium point within finite time and then go to equilibrium point asymptotically. The appealing features of the proposed control are fast convergence, high precision, strong robustness, and easy implementation. Simulations verify the effectiveness of the proposed approach.

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