Three-dimensional finite-time guidance law based on sliding mode adaptive RBF neural network against a highly manoeuvering target

2022 ◽  
pp. 1-20
Author(s):  
G. Wu ◽  
K. Zhang ◽  
Z. Han

Abstract In order to intercept a highly manoeuvering target with an ideal impact angle in the three-dimensional space, this paper promises to probe into the problem of three-dimensional terminal guidance. With the goal of the highly target acceleration and short terminal guidance time, a guidance law, based on the advanced fast non-singular terminal sliding mode theory, is designed to quickly converge the line-of-sight (LOS) angle and the LOS angular rate within a finite time. In the design process, the target acceleration is regarded as an unknown boundary external disturbance of the guidance system, and the RBF neural network is used to estimate it. In order to improve the estimation accuracy of RBF neural network and accelerate its convergence, the parameters of RBF neural network are adjusted online in real time. At the same time, an adaptive law is designed to compensate the estimation error of the RBF neural network, which improves the convergence speed of the guidance system. Theoretical analysis demonstrates that the state and the sliding manifold of the guidance system converge in finite time. According to Lyapunov theory, the stability of the system can be guaranteed by online adjusting the parameters of RBF neural network and adaptive parameters. The numerical simulation results verify the effectiveness and superiority of the proposed guidance law.

2018 ◽  
Vol 41 (1) ◽  
pp. 182-192 ◽  
Author(s):  
Junhong Song ◽  
Shenmin Song

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.


2016 ◽  
Vol 2016 ◽  
pp. 1-19 ◽  
Author(s):  
Bin Zhao ◽  
Jun Zhou

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.


2021 ◽  
Vol 2021 ◽  
pp. 1-19
Author(s):  
Gang Wu ◽  
Ke Zhang

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.


Author(s):  
Zhengyu Guo ◽  
Chaolei Wang ◽  
Hang Qian ◽  
Zhiguo Han ◽  
Jingxian Zhang

A distributed multi-missile cooperative guidance law based on the finite time theory is proposed to solve the terminal guidance problem of three-dimensional multi-missiles cooperative interception of large maneuvering target. According to the finite time consistency theory, an adaptive guidance law based on the integral sliding mode is designed to ensure that all missiles can reach the target at the same time in the terminal guidance process. The longitudinal and lateral acceleration of the line of sight are based on the guidance law of the fast terminal sliding mode surface. The terminal attack angle is constrained, so that the terminal attack Angle can reach the expected value in finite time. The simulation results show that the designed guidance law can achieve the cooperative attack on the maneuvering targets.


Author(s):  
Li Hongxia ◽  
Deng Yifan ◽  
Yuanli Cai

This article proposes a new terminal cooperative guidance law with impact time constraint in three-dimensional (3D) engagement. Two parts are comprised by this guidance scheme to control the impact time and fulfill the interception. The guidance law along the line-of-sight (LOS) direction is first designed based on finite time consensus protocol to share time-to-go values among missiles and reach the consensus. Meanwhile, the guidance law on the LOS normal direction is developed based on the fast finite time control method to achieve the interception. The stability analysis of the proposed guidance law based on the Lyapunov theory is also demonstrated in detail. Moreover, the maneuvering target can be intercepted successfully under the presented control algorithm, and the guidance system can fulfill stability within finite time. Additionally, the effectiveness and applicability of the proposed guidance scheme are explicitly verified through simulation tests.


Author(s):  
Fei Ma ◽  
Yunjie Wu ◽  
Siqi Wang ◽  
Xiaofei Yang ◽  
Yueyang Hua

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.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Yao Yang ◽  
Yang Xu ◽  
Pei Wang

To explore the influence of the trace point step-jump behavior on a terminal guidance system, an analysis is performed from the line-of-sight rate (LOS rate) and guidance accuracy views for designing an anti-step-jump guidance law. First, the linear terminal guidance model under the trace point jump circumstance is constructed, and then the fundamental reason for the miss distance is investigated by deriving the upper bound of the LOS rate at the initial step-jump moment. Following this, the novel proposed analytical differential adjoint model is established with the adjoint method, and its validity is demonstrated comparing with the numeric derivative model. Based on the adjoint model, the effects of the ratio coefficient, the time constant, and the jump amplitude on the guidance accuracy are explored. Finally, a novel anti-step-jump guidance law is designed to shorten the recovery time of the overload. The simulations have shown that the faster recovery time and higher accuracy are achieved in comparison with the proportional navigation guidance, optimal guidance, and adaptive sliding mode guidance.


Author(s):  
Di Zhou ◽  
Sheng Sun ◽  
Jing Yang Zhou ◽  
Kok Lay Teo

Based on the discrete form of the target-missile relative motion equations in plane, a discrete sliding-mode guidance (DSMG) law is proposed. All previous missile seeker's measurements are used in the design of the DSMG law to estimate the target acceleration such that noises in the seeker's measurements are effectively being smoothened. It is proved that the proposed DSMG law is finite time convergent. Quasi sliding-mode bands of the DSMG law are discussed, and the formula for calculating the terminal miss distances of the missile under the DSMG law are presented. Simulation results from a space interception process verify the effectiveness of the proposed method.


Author(s):  
Sheng Sun ◽  
Di Zhou ◽  
Jingyang Zhou ◽  
Kok Lay Teo

The true proportional navigation guidance law, the augmented proportional navigation guidance law, or the adaptive sliding-mode guidance law, is designed based on the planar target-to-missile relative motion dynamics. By a proper construction of a nonlinear Lyapunov function for the line-of-sight angular rates in the three-dimensional guidance dynamics, it is shown that the three guidance laws mentioned above are able to ensure the asymptotic convergence of the angular rates as they are directly applied to the three-dimensional guidance environment. Furthermore, considering the missile autopilot dynamics as a first-order lag, we design three-dimensional nonlinear guidance laws by using the backstepping technique for three cases: (1) the target does not maneuver; (2) the information of target acceleration can be acquired; and (3) the target acceleration is not available but its bound is known a priori. In the first step of the backstepping design of the control law, there is no need to cancel the nonlinear coupling terms in the three-dimensional guidance dynamics in such way that the final expressions of the proposed guidance laws are significantly simplified. Thus, the proposed nonlinear Lyapunov function for the line-of-sight angular rates is a generalized function for designing three-dimensional guidance laws. Simulation results of a missile interception mission show that the proposed guidance laws are highly effective.


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