scholarly journals Adaptive Super-Twisting Algorithm-Based Nonsingular Terminal Sliding Mode Guidance Law

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Fang Yang ◽  
Kuanqiao Zhang ◽  
Lei Yu
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Fixed Time ◽  
Impact Angle ◽  
Terminal Sliding Mode ◽  
Finite Time Convergence ◽  
Guidance Law ◽  
Fast Terminal Sliding Mode ◽  
The Impact ◽  
Impact Angle Constraint

A nonsingular fast terminal sliding mode guidance law with an impact angle constraint is proposed to solve the problem of missile guidance accuracy and impact angle constraint for maneuvering targets. Aiming at the singularity problem of the terminal sliding mode, a fast terminal sliding mode surface with finite-time convergence and impact angle constraint is designed based on fixed-time convergence and piecewise sliding mode theory. To weaken chattering and suppress interference, a second-order sliding mode supertwisting algorithm is improved. By designing the parameter adaptive law, an adaptive smooth supertwisting algorithm is designed. This algorithm can effectively weaken chattering without knowing the upper bound information of interference, and it converges faster. Based on the proposed adaptive supertwisting algorithm and the sliding mode surface, a guidance law with the impact angle constraint is designed. The global finite-time convergence of the guidance law is proved by constructing the Lyapunov function. The simulation results verify the effectiveness of the proposed guidance law, and compared with the existing terminal sliding mode guidance laws, the proposed guidance law has higher guidance precision and angle constraint accuracy.

scholarly journals Second-Order Sliding Mode Guidance Law considering Second-Order Dynamics of Autopilot

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Kuanqiao Zhang ◽  
Suochang Yang
Keyword(s):  
Dynamic Characteristics ◽  
Finite Time ◽  
Sliding Mode ◽  
Impact Angle ◽  
Second Order ◽  
Terminal Sliding Mode ◽  
Finite Time Convergence ◽  
Guidance Law ◽  
Impact Angle Constraint ◽  
Second Order Sliding Mode

Aiming at the requirement that some missiles need to meet certain impact angles when attacking targets, we consider the second-order dynamic characteristics of autopilot, thereby proposing a second-order sliding mode guidance law with impact angle constraint. Firstly, based on the terminal sliding mode control, we design a fast nonsingular terminal sliding mode guidance law with impact angle constraint. Based on the second-order sliding mode control, a second-order sliding mode guidance law with impact angle constraint is proposed. We have proved its finite time convergence characteristics and presented the specific convergence time expression. Subsequently, the dynamic characteristics of the autopilot are approximated to the second-order link. Combined with the dynamic surface control theory, we proposed a second-order sliding mode guidance law considering the second-order dynamic characteristics of the autopilot and proved its finite-time convergence characteristics. Finally, the effectiveness and superiority of the proposed guidance law are verified by comparative simulation experiments.

scholarly journals Two-Phase Optimal Guidance Law considering Impact Angle Constraint with Bearings-Only Measurements

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Tianning Wang ◽  
Shengjing Tang ◽  
Jie Guo ◽  
Haoqiang Zhang
Keyword(s):  
Sliding Mode ◽  
Information Matrix ◽  
Impact Angle ◽  
Estimation Accuracy ◽  
Two Phase ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Optimal Guidance ◽  
The Impact ◽  
Impact Angle Constraint

The implementation of advanced guidance laws with bearings-only measurements requires estimation of the range information. To improve estimation accuracy and satisfy the impact angle constraint, this paper proposes a two-phase optimal guidance law consisting of an observing phase and an attacking phase. In the observing phase, the determinant of Fisher information matrix is maximized to achieve the optimal observability and a suboptimal solution expressed by leading angle is derived analytically. Then, a terminal sliding-mode guidance law is designed to track the desired leading angle. In the followed attacking phase, an optimal guidance law is integrated with a switching term to satisfy both the impact angle constraint and the field-of-view constraint. Finally, comparison studies of the proposed guidance law and a traditional optimal guidance law are conducted on stationary targets and maneuvering targets cases. Simulation results demonstrate that the proposed guidance law is able to improve the range observability and achieve better terminal performances including impact angle accuracy and miss distance.

scholarly journals Smooth Adaptive Finite Time Guidance Law with Impact Angle Constraints

2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Bin Zhao ◽  
Jun Zhou
Keyword(s):  
Finite Time ◽  
Sliding Mode ◽  
Impact Angle ◽  
Guidance System ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Adaptive Law ◽  
Target Acceleration ◽  
Control Scheme ◽  
Fast Terminal Sliding Mode

A smooth guidance law for intercepting a maneuvering target with impact angle constraints is documented based on the nonsingular fast terminal sliding mode control scheme and adaptive control scheme. Different from the traditional adaptive law which is used to estimate the unknown upper bound of the target acceleration, a new adaptive law is proposed to estimate the square of target acceleration bound, which avoids the use of the nonsmooth signum function and therefore ensures the smoothness of the guidance law. The finite time convergence of the guidance system is guaranteed based on the Lyapunov method and the finite time theory. Simulation results indicate that under the proposed guidance law the missile can intercept the target with a better accuracy at a desired impact angle in a shorter time with a completely smooth guidance command compared with the existing adaptive fast terminal sliding mode guidance laws, which shows the superiority of this method.

Cooperative guidance law for intercepting a hypersonic target with impact angle constraint

2022 ◽  
pp. 1-19
Author(s):  
S. Liu ◽  
B. Yan ◽  
R. Liu ◽  
P. Dai ◽  
J. Yan ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Sliding Mode ◽  
Impact Angle ◽  
Terminal Sliding Mode ◽  
Guidance Law ◽  
Cooperative Guidance ◽  
Simulation Results ◽  
Twisting Algorithm ◽  
The Impact ◽  
Impact Angle Constraint

Abstract The cooperative guidance problem of multiple inferior missiles intercepting a hypersonic target with the specific impact angle constraint in the two-dimensional plane is addressed in this paper, taking into consideration variations in a missile’s speed. The guidance law is designed with two subsystems: the direction of line-of-sight (LOS) and the direction of normal to LOS. In the direction of LOS, by applying the algebraic graph theory and the consensus theory, the guidance command is designed to make the system convergent in a finite time to satisfy the goal of cooperative interception. In the direction of normal to LOS, the impact angle is constrained to transform into the LOS angle at the time of interception. In view of the difficulty of measuring unknown target acceleration information in real scenarios, the guidance command is designed by utilising a super-twisting algorithm based on a nonsingular fast-terminal sliding mode (NFTSM) surface. Numerical simulation results manifest that the proposed guidance law performs efficiently and the guidance commands are free of chattering. In addition, the overall performance of this guidance law is assessed with Monte Carlo runs in the presence of measurement errors. The simulation results demonstrate that the robustness can be guaranteed, and that overall efficiency and accuracy in intercepting the hypersonic target are achieved.

Fixed-time cooperative guidance for multiple missiles with impact angle constraint

2021 ◽  
pp. 095441002110480
Author(s):  
Xinghe Zhou ◽  
Weihong Wang ◽  
Zhenghua Liu
Keyword(s):  
Sliding Mode ◽  
Angular Rate ◽  
Fixed Time ◽  
Impact Angle ◽  
Terminal Sliding Mode ◽  
Maneuvering Target ◽  
Guidance Law ◽  
Multiple Missiles ◽  
Cooperative Guidance ◽  
Impact Angle Constraint

For the guidance problem of multiple missiles attacking a maneuvering target simultaneously in plane, a novel fixed-time distributed cooperative guidance law with impact angle constraint is designed in this paper. The design process of distributed cooperative guidance law can be roughly divided into two parts. First, based on the nonsingular terminal sliding mode control, a cooperative guidance law on the line-of-sight (LOS) direction is developed, which can guarantee that all missiles hit the maneuvering target simultaneously. Second, another guidance law in normal direction of the LOS direction is designed to achieve the fixed-time convergence of LOS angular rate and LOS angle. Finally, numerical simulations verify the effectiveness of the proposed cooperative guidance law for different engagement scenarios.

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.

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.

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.

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