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

Fang Yang,Lei Yu,Kuanqiao Zhang

doi:10.1155/2020/1058347

Abstract

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.

Highlights

In modern warfare, many missiles need to hit the target with certain impact angles to increase the damage effectiveness of the warheads. erefore, the impact angle constraint is a problem that needs to be considered in the design of the guidance law [1].Sliding mode control is widely used in the design of the guidance law because of its invariability to interference in the sliding mode
Guidance Law Design e terminal sliding mode control adopts the nonlinear function as the sliding mode surface, which can make the system states converge in finite time, but the method has singular problems
In order to verify the superiority of the designed guidance law, this section carries out the nonsingular fast terminal sliding mode guidance law (NFTSMG) proposed in [23] and the second-order nonsingular terminal sliding mode guidance law (SONTSMG) proposed in [24] to perform a comparative simulation. e expression of NFTSMG is u cos r q−

Summary

Introduction

Many missiles (such as some antiship missiles, antitank missiles, and air defense missiles) need to hit the target with certain impact angles to increase the damage effectiveness of the warheads. erefore, the impact angle constraint is a problem that needs to be considered in the design of the guidance law [1]. For the finite-time control problem, a finite-time convergence guidance law with the impact angle constraint is designed based on the terminal sliding mode control in [4,5,6]. The control law of the supertwisting algorithm is not smooth, the parameter selection needs to know the upper boundary information of system disturbance, and the convergence speed is slow when the system states are far from the equilibrium point. Based on the idea of fixed-time convergence and piecewise sliding surface, a nonsingular fast terminal sliding surface with the impact angle constraint is designed. A nonsingular fast terminal sliding mode guidance law with the impact angle constraint is proposed based on the adaptive supertwisting algorithm. The effectiveness and superiority of the guidance law are verified by simulation experiments

Preparatory Knowledge

Adaptive Fast Supertwisting Algorithm

Simulation Analysis

Conclusion