scholarly journals A finite-time 3D guidance law based on fixed-time convergence disturbance observer

2020 ◽  
Vol 33 (4) ◽  
pp. 1299-1310
Author(s):  
Feng YANG ◽  
Guangqing XIA
Keyword(s):  
Finite Time ◽  
Disturbance Observer ◽  
Fixed Time ◽  
Guidance Law ◽  
3D Guidance

scholarly journals Fixed-Time Disturbance Observer-Based Adaptive Finite-Time Guidance Law Design considering Impact Angle Constraint and Autopilot Dynamics

Complexity ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-18
Author(s):  
Yunjie Wu ◽  
Fei Ma ◽  
Xiaofei Yang ◽  
Siqi Wang ◽  
Xiaodong Liu
Keyword(s):  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Lyapunov Stability Theory ◽  
Fixed Time ◽  
Impact Angle ◽  
Guidance Law ◽  
Adaptive Laws ◽  
Impact Angle Constraint ◽  
Guidance Problem

This paper aims to establish an effective guidance law to accomplish the interception guidance mission for a missile intercepting a target with impact angle constraint and autopilot dynamics. To achieve this purpose, a fixed-time disturbance observer-based adaptive finite-time guidance law is presented. First, a fixed-time disturbance observer (FTDO) is designed to guarantee the fast estimation of the lumped disturbance caused by the target maneuver. Then, the FTDO-based adaptive integral sliding mode backstepping (AISMB) guidance law is constructed for the interception guidance problem. Besides, several adaptive laws are established to estimate the derivative of virtual control inputs, making the “differential explosion problem” of conventional backstepping get avoided. The finite-time convergence characteristic of the closed-loop system is analyzed by utilizing the Lyapunov stability theory. Finally, the simulation examples are conducted to demonstrate the effectiveness of the proposed composite guidance law.

scholarly journals A Composite Guidance Law for Suppressing Measurement Noise of LOS Angular Rate

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Feng Chen ◽  
Guangjun He ◽  
Qifang He
Keyword(s):  
Sliding Mode Control ◽  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Angular Rate ◽  
Measurement Noise ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Fast Terminal Sliding Mode ◽  
Low Altitude

To effectively intercept a low-altitude target in clutter background, a nonsingular fast terminal sliding mode guidance law is designed. The designed guidance law can fully exploit the fast convergence characteristics of linear sliding mode control and the finite-time-convergent characteristics of terminal sliding mode control to ensure that the line-of-sight (LOS) angle converges to a desired angle in a limited time at a faster rate. Utilizing the smooth switching characteristics of the hyperbolic tangent function similar to the saturation function, a finite-time-convergent differentiator is designed. Meanwhile, a new finite-time-convergent disturbance observer designed on the tracking differentiator can effectively track the ideal LOS angular rate, suppress the measurement noise, and make a smooth estimation of the target maneuvering acceleration in clutter background. Combining the estimated value of the disturbance observer, the sign function with switch coefficient is introduced to design a composite nonsingular fast terminal sliding mode guidance law. The simulation results show that the composite guidance law can not only effectively suppress the measurement noise of the LOS angular rate and improve the accuracy of low-altitude target intercepting, but also greatly reduce the energy consumption in the interception process.

Super-twisting integral-sliding-mode guidance law considering autopilot dynamics

2017 ◽  
Vol 232 (9) ◽  
pp. 1787-1799 ◽  
Author(s):  
Kezi Meng ◽  
Di Zhou
Keyword(s):  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Lyapunov Stability Theory ◽  
Guidance System ◽  
Integral Sliding Mode ◽  
Finite Time Stability ◽  
Guidance Law ◽  
Chattering Free ◽  
Twisting Algorithm

A new guidance law considering missile autopilot dynamics is established via integrating a smooth super-twisting algorithm with nonlinear integral sliding mode. In this guidance law, a finite-time disturbance observer is introduced to estimate mismatched and matched disturbances resulting from target maneuvers. Based on Lyapunov stability theory, the finite-time stability of the closed-loop guidance system under this law is analyzed using a finite-time bounded function. The super-twisting algorithm guarantees that the proposed guidance law is chattering-free and the disturbance observer does not depend on the prior knowledge of target acceleration. So the proposed guidance law is easy to be implemented in practice. The finite-time convergence and robustness of the proposed guidance law are demonstrated via numerical simulations accounting for missile autopilot dynamics.

scholarly journals Design of Second-Order Sliding Mode Guidance Law Based on the Nonhomogeneous Disturbance Observer

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Huibo Zhou ◽  
Shenmin Song ◽  
Junhong Song ◽  
Jing Niu
Keyword(s):  
Dynamic Characteristics ◽  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Time Estimation ◽  
Variable Structure ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Power Rate ◽  
Guidance Laws

Considering the guidance problem of relative motion of missile target without the dynamic characteristics of missile autopilot in the interception planar, non-homogeneous disturbance observer is applied for finite-time estimation with respect to the target maneuvering affecting the guidance performance. Two guidance laws with finite-time convergence are designed by using a fast power rate reaching law and the prescribed sliding variable dynamics. The nonsingular terminal sliding mode surface is selected to improve dynamic characteristics of missile autopilot. Furthermore, the finite-time guidance law with dynamic delay characteristics is designed for the target maneuvering through adopting variable structure dynamic compensation. The simulation results demonstrate that, for different target maneuvering, the proposed guidance laws can restrain the sliding mode chattering problem effectively and make the missile hit the maneuvering target quickly and accurately with condition of corresponding assumptions.

A novel finite-time disturbance observer-based partial control design: A guidance application

2019 ◽  
Vol 26 (11-12) ◽  
pp. 1001-1011 ◽  
Author(s):  
Hamid Razmjooei ◽  
Mohammad Hossein Shafiei
Keyword(s):  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Guidance System ◽  
State Variables ◽  
Time Stability ◽  
Terminal Sliding Mode ◽  
Partial Control ◽  
Finite Time Stability ◽  
Guidance Law

This paper presents a novel technique to design a robust finite-time partial stabilizer, based on the non-singular terminal sliding mode method and a disturbance observer for the missile guidance problem. In the proposed method, the finite-time stability is desired for only a part of the state variables in the guidance system. Accordingly, the guidance system is divided into two subsystems where the finite-time stability is desired only for the first subsystem. Then, a partial diffeomorphism transformation is used to convert the first subsystem into the normal form. Finally, the components of the input vector appearing in the transformed form of the first subsystem are designed to achieve finite-time stability based on a partial disturbance observer. In the proposed finite-time disturbance observer, the disturbances are estimated in a finite time without any knowledge about their upper bounds. Simulation results demonstrate the effectiveness of the designed guidance law to intercept maneuvering and non-maneuvering targets compared to the existing methods.

scholarly journals Strictly Finite-Time-Convergent Missile Guidance Law Based on Adaptive-Gain Observer

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Jun Zhou ◽  
Yang Wang
Keyword(s):  
Upper Bound ◽  
Finite Time ◽  
Disturbance Observer ◽  
Closed Loop ◽  
Time Varying ◽  
Missile Guidance ◽  
Sliding Surface ◽  
Closed Loop System ◽  
Guidance Law ◽  
Target Acceleration

In the absence of the upper bound of time-varying target acceleration, the finite-time-convergent guidance (FTCG) problem for missile is addressed in this paper. Firstly, a novel adaptive finite-time disturbance observer (AFDO) is developed based on adaptive-gain super twisting (ASTW) algorithm to estimate the unknown target acceleration. Subsequently, a new FTCG law is proposed by using the output of AFDO. The newly proposed FTCG law has several advantages over existing FTCG laws. First, for time-varying target acceleration, the proposed method can strictly guarantee the trajectory of the closed-loop system is driven onto the sliding surface rather than a neighbourhood of sliding surface in the extended-state-observer-based FTCG (ESOFTCG) law. Second, the proposed method requires no upper bound information on the target acceleration. Third, the chattering problem in the conventional FTCG (CFTCG) law is completely avoided in this paper. Simulation result demonstrates the effectiveness of the proposed AFDO and the proposed FTCG law.

scholarly journals A Novel Guidance Law for Intercepting a Highly Maneuvering Target

2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Gang Wu ◽  
Ke Zhang
Keyword(s):  
Neural Network ◽  
Finite Time ◽  
Disturbance Observer ◽  
Sliding Mode ◽  
Rbf Neural Network ◽  
Input Saturation ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Nonsingular Terminal Sliding Mode ◽  
Command Input

Given the resolution of the guidance for intercepting highly maneuvering targets, a novel finite-time convergent guidance law is proposed, which takes the following conditions into consideration, including the impact angle constraint, the guidance command input saturation constraint, and the autopilot second-order dynamic characteristics. Firstly, based on the nonsingular terminal sliding mode control theory, a finite-time convergent nonsingular terminal sliding mode surface is designed. On the back of the backstepping control method, the virtual control law appears. A nonlinear first-order filter is constructed so as to address the “differential expansion” problem in traditional backstepping control. By designing an adaptive auxiliary system, the guidance command input saturation problem is dealt with. The RBF neural network disturbance observer is used for estimating the unknown boundary external disturbances of the guidance system caused by the target acceleration. The parameters of the RBF neural network are adjusted online in real time, for the purpose of improving the estimation accuracy of the RBF neural network disturbance observer and accelerating its convergence characteristics. At the same time, an adaptive law is designed to compensate the estimation error of the RBF neural network disturbance observer. Then, the Lyapunov stability theory is used to prove the finite-time stability of the guidance law. Finally, numerical simulations verify the effectiveness and superiority of the proposed guidance law.

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