scholarly journals A New Fast Nonsingular Terminal Sliding Mode Control for a Class of Second-Order Uncertain Systems

2016 ◽  
Vol 2016 ◽  
pp. 1-12 ◽  
Author(s):  
Linjie Xin ◽  
Qinglin Wang ◽  
Yuan Li
Keyword(s):  
Uncertain Systems ◽  
Sliding Mode ◽  
Second Order ◽  
Terminal Sliding Mode ◽  
Nonsingular Terminal Sliding Mode ◽  
Exponential Decline ◽  
Control Scheme ◽  
Fast Convergence Rate ◽  
The Stability

This paper considers the robust and adaptive nonsingular terminal sliding mode (NTSM) control for a class of second-order uncertain systems. First, a new fast NTSM was proposed which had global fast convergence rate in the sliding phase. Then, a new form of robust NTSM controller was designed to handle a wider class of second-order uncertain systems. Moreover, an exponential-decline switching gain was introduced for chattering suppression. After that, a double sliding surfaces control scheme was constructed to combine the NTSM control with the adaptive technique. The benefit is that a strict demonstration can be given for the stagnation problem in the stability analysis of NTSM. Finally, a case study for tracking control of a variable-length pendulum was performed to verify the proposed controllers.

Design of adaptive optimal robust control for two-flexible-link manipulators in the presence of matched uncertainties

2020 ◽  
pp. 107754632093202
Author(s):  
Hamid Reza Shafei ◽  
Mohsen Bahrami ◽  
Heidar Ali Talebi
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Flexible Link ◽  
External Disturbances ◽  
Terminal Sliding Mode ◽  
Control Approach ◽  
Mode Control ◽  
Nonsingular Terminal Sliding Mode ◽  
Control Scheme ◽  
The Stability

This study uses a comprehensive control approach to deal with the trajectory tracking problem of a two-flexible-link manipulator subjected to model uncertainties. Because the control inputs of two-flexible-link manipulators are less than their state variables, the proposed controller should be able to tackle the stated challenge. Practically speaking, there is only a single control signal for each joint, which can be used to suppress link deflections and control joint trajectories. To achieve this objective, a novel optimal robust control scheme, with an updated gain under the adaptive law, has been developed in this work for the first time. In this regard, a nonsingular terminal sliding mode control approach is used as the robust controller and a control Lyapunov function is used as the optimal control law, to benefit from the advantages of both methods. To systematically deal with system uncertainties, an adaptive law is used to update the gain of nonsingular terminal sliding mode control. The advantage of this approach over the existing methods is that it not only can robustly and stably control an uncertain nonlinear system against external disturbances but also can optimally solve a quadratic cost function (e.g. minimization of control effort). The Lyapunov stability theory has been applied to verify the stability of the proposed approach. Moreover, to show the superiority of this method, the computer simulation results of the proposed method have been compared with those of an adaptive sliding mode control scheme. This comparison shows that the presented approach is capable of optimizing the control inputs while achieving the stability of the examined two-flexible-link manipulator in the presence of model uncertainties and external disturbances.

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.

Second-order fast terminal sliding mode control design based on LMI for a class of non-linear uncertain systems and its application to chaotic systems

2016 ◽  
Vol 23 (18) ◽  
pp. 2912-2925 ◽  
Author(s):  
Saleh Mobayen ◽  
Dumitru Baleanu ◽  
Fairouz Tchier
Keyword(s):  
Sliding Mode Control ◽  
Uncertain Systems ◽  
Sliding Mode ◽  
Second Order ◽  
Control Technique ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Fast Terminal Sliding Mode ◽  
Non Linear

In this paper, an linear matrix inequalities (LMI)-based second-order fast terminal sliding mode control technique is investigated for the tracking problem of a class of non-linear uncertain systems with matched and mismatched uncertainties. Using the offered approach, a robust chattering-free control scheme is presented to prove the presence of the switching around the sliding surface in the finite time. Based on the Lyapunov stability theorem, the LMI conditions are presented to make the state errors into predictable bounds and the parameters of the controller are obtained in the form of LMI. The control structure is independent of the order of the model. Then, the proposed method is fairly simple and there is no difficulty in the use of this scheme. Simulations on the well-known Genesio's chaotic system and Chua's circuit system are employed to emphasize the success of the suggested scheme. The simulation results on the Genesio's system demonstrate that the offered technique leads to the superior improvement on the control effort and tracking performance.

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