scholarly journals Robust Smooth Sliding-Mode-Based Controller with Fixed-Time Convergence for Missiles considering Aerodynamic Uncertainty

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Yuhang Yun ◽  
Jie Guo ◽  
Shengjing Tang
Keyword(s):  
Performance Metrics ◽  
Sliding Mode ◽  
Initial Conditions ◽  
Fixed Time ◽  
Convergence Theory ◽  
Control Technique ◽  
Control Input ◽  
Initial State ◽  
Terminal Sliding Mode ◽  
Signum Function

This paper designed a smooth fixed-time-convergent sliding mode controller for a missile flight system considering aerodynamic uncertainties. Fixed-time convergence theory is incorporated with the sliding mode control technique to ensure that the system tracks desired commands within uniform bounded time under different initial conditions. Unlike previous terminal sliding mode approaches, not only is the bound of settling time independent of initial state, indicating that performance metrics like convergence rate can be predicted beforehand, but the control input is designed to be smooth based on adaptive estimations and some mathematical results without introducing any discontinuous items like the signum function, which avoids the problem of chattering consequently. A cascade control structure is employed with the derived control algorithm, and therein, the control input signal is obtained. Finally, a number of simulations are carried out and demonstrate the effectiveness of the designed controller.

Smooth adaptive fixed time convergent controller design for BTT missiles with uncertainties

2019 ◽  
Vol 124 (1273) ◽  
pp. 323-345
Author(s):  
Y. Yun ◽  
S. Tang ◽  
J. Guo ◽  
Y. Yun
Keyword(s):  
Control Algorithm ◽  
Performance Metrics ◽  
Controller Design ◽  
Sliding Mode ◽  
Fixed Time ◽  
Convergence Time ◽  
Control Input ◽  
Time Stability ◽  
Terminal Sliding Mode ◽  
Satisfactory Performance

ABSTRACTA smooth adaptive sliding-mode-based controller is developed for BTT missiles considering nonlinear couplings and aerodynamic uncertainties, wherein fixed-time stability theory is synthesised into sliding-mode control algorithm, such that control variables follow the desired command within fixed-bounded convergence time. Unlike other terminal sliding-mode-related works, the bound of settling time is independent of initial states, indicating that performance metrics, for instance the convergence rate, can be evaluated in advance. The control input is designed to be intrinsically smooth, based on adaptive estimations, and therefore the problem of singularity and chattering is effectively eliminated. Simulation results demonstrate the satisfactory performance and validate the effectiveness of the designed approach.

scholarly journals Fixed-time Stabilization for Uncertain Chained Systems with Sliding Mode and RBF Neural Network

2019 ◽  
Author(s):  
Guo Pengfei ◽  
Liang Zhenying ◽  
Wang Xi ◽  
Jin Zengke
Keyword(s):  
Neural Network ◽  
Sliding Mode ◽  
Rbf Neural Network ◽  
Fixed Time ◽  
Settling Time ◽  
Initial State ◽  
Terminal Sliding Mode ◽  
Control Laws ◽  
Control Approach ◽  
Form System

In this paper, the fixed-time stabilization problem for a class of uncertain chained system is addressed by using a novel nonsingular recursive terminal sliding mode control approach. A fixed-time controller and an adaptive law are designed to guarantee the uncertain chained form system both Lyapunov stable and fixed-time convergent within the settling time. The advantage of the controller based on the sliding mode is that the settling time does not depend on the system initial state. Furthermore, we use RBF neural network to estimate the uncertainty of the system. Finally, the simulation results demonstrate the performance of the control laws.

scholarly journals Dynamical Analysis and Stabilization of Wind Turbine Drivetrain via Adaptive Fixed-Time Terminal Sliding Mode Controller

2019 ◽  
Vol 2019 ◽  
pp. 1-14
Author(s):  
Jianxiang Yang ◽  
Anle Mu ◽  
Nailu Li
Keyword(s):  
Wind Turbine ◽  
Sliding Mode ◽  
Initial Conditions ◽  
Chaotic Oscillation ◽  
Fixed Time ◽  
Dynamical Analysis ◽  
Sliding Mode Controller ◽  
Damping Force ◽  
Terminal Sliding Mode ◽  
The Stability

In order to study the stability of the wind turbine drivetrain in further depth, we present a nonlinear relative rotation mathematical model considering the nonlinear time-varying stiffness and the nonlinear damping force. Meanwhile, the nonlinear dynamics of the model under combined harmonic excitation are studied in detail. And some interesting dynamic phenomena are observed visually. Furthermore, to suppress chaotic oscillation within bounded time independent of initial conditions, a novel adaptive fixed-time terminal sliding mode controller is proposed. The stability of the final closed loop system is guaranteed according to Lyapunov stability theory. Rigorous mathematical analyses are used to prove the validity of the presented approach. Finally, compared with the existing finite-time stability method, simulation results are given to highlight the effectiveness and superiority of the proposed method and verify the theoretical analyses.

scholarly journals Formation Tracking Control for Multi-Agent Networks with Fixed Time Convergence via Terminal Sliding Mode Control Approach

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1416
Author(s):  
Guang-Hui Xu ◽  
Meng Li ◽  
Jie Chen ◽  
Qiang Lai ◽  
Xiao-Wen Zhao
Keyword(s):  
Tracking Control ◽  
Sliding Mode ◽  
Fixed Time ◽  
Stability Theorem ◽  
Control Task ◽  
Terminal Sliding Mode ◽  
Formation Tracking ◽  
Multi Agent ◽  
Error System ◽  
Agent Networks

This paper investigates formation tracking control for multi-agent networks with fixed time convergence. The control task is that the follower agents are required to form a prescribed formation within a fixed time and the geometric center of the formation moves in sync with the leader. First, an error system is designed by using the information of adjacent agents and a new control protocol is designed based on the error system and terminal sliding mode control (TSMC). Then, via employing the Lyapunov stability theorem and the fixed time stability theorem, the control task is proved to be possible within a fixed time and the convergence time can be calculated by parameters. Finally, numerical results illustrate the feasibility of the proposed control protocol.

Design of a non-singular fast terminal sliding mode control for second-order nonlinear systems with compound disturbance

2021 ◽  
pp. 095440622110329
Author(s):  
Mohammad Reza Salehi Kolahi ◽  
Mohammad Reza Gharib ◽  
Ali Heydari
Keyword(s):  
Sliding Mode Control ◽  
Sliding Mode ◽  
Path Tracking ◽  
Second Order ◽  
Control Technique ◽  
Terminal Sliding Mode Control ◽  
Terminal Sliding Mode ◽  
Mode Control ◽  
Fast Terminal Sliding Mode ◽  
Compound Disturbance

This paper investigates a new disturbance observer based non-singular fast terminal sliding mode control technique for the path tracking and stabilization of non-linear second-order systems with compound disturbance. The compound disturbance is comprised of both parametric and non-parametric uncertainties. While warranting fast convergence rate and robustness, it also dominates the singularity and complex-value number issues associated with conventional terminal sliding mode control. Furthermore, due to the estimation properties of the observer, knowledge about the bounds of the uncertainties is not required. The simulation results of two case studies, the velocity and path tracking of an autonomous underwater vehicle and the stabilization of a chaotic Φ6-Duffing oscillator, validate the efficacy of the proposed method.

Three-dimensional adaptive fixed-time guidance law against maneuvering targets with impact angle constraints and control input saturation

2021 ◽  
pp. 014233122110598
Author(s):  
Fei Ma ◽  
Yunjie Wu ◽  
Siqi Wang ◽  
Xiaofei Yang ◽  
Yueyang Hua
Keyword(s):  
Sliding Mode ◽  
Input Saturation ◽  
Three Dimensional ◽  
Fixed Time ◽  
Impact Angle ◽  
Guidance System ◽  
Control Input ◽  
Guidance Law ◽  
The Stability ◽  
And Control

This paper presents an adaptive fixed-time guidance law for the three-dimensional interception guidance problem with impact angle constraints and control input saturation against a maneuvering target. First, a coupled guidance model formulated by the relative motion equation is established. On this basis, a fixed-time disturbance observer is employed to estimate the lumped disturbances. With the help of this estimation technique, the adaptive fixed-time sliding mode guidance law is designed to accomplish accurate interception. The stability of the closed-loop guidance system is proven by the Lyapunov method. Simulation results of different scenarios are executed to validate the effectiveness and superiority of the proposed guidance law.

Robust impact angle constraints guidance law with autopilot lag and acceleration saturation consideration

2018 ◽  
Vol 41 (1) ◽  
pp. 182-192 ◽  
Author(s):  
Junhong Song ◽  
Shenmin Song
Keyword(s):  
Upper Bound ◽  
Finite Time ◽  
Sliding Mode ◽  
Three Dimensional ◽  
Impact Angle ◽  
Guidance System ◽  
Control Technique ◽  
Backstepping Method ◽  
Terminal Sliding Mode ◽  
Guidance Law

In this paper, for the three-dimensional terminal guidance problem of a missile intercepting a manoeuvring target, a robust continuous guidance law with impact angle constraints in the presence of both an acceleration saturation constraint and a second-order-lag autopilot is developed. First, based on non-singular fast terminal sliding mode and adaptive control, a step-by-step backstepping method is used to design the guidance law. In the process of guidance law design, with the use of a finite-time control technique, virtual control laws are developed, a tracking differentiator is used to eliminate the ‘explosion of complexity’ problem inherent in the traditional backstepping method, and an additional system is constructed to deal with the acceleration saturation problem; its states are used for guidance law design and stability analysis. Moreover, the target acceleration is considered bounded disturbance, but the upper bound is not required to be known in advance, whereas the upper bound is estimated online by a designed adaptive law. Next, finite-time stability of the guidance system is strictly proved by using a Lyapunov method. Finally, numerical simulations are presented to demonstrate the excellent guidance performances of the proposed guidance law in terms of accuracy and efficiency.

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