Study on Autopilot Dynamics with Robust Guidance Law and Terminal Constraint in Mechanical Engineering

2013 ◽  
Vol 644 ◽  
pp. 77-80
Author(s):  
Zhi Ping Li ◽  
Jun Zhou ◽  
Jian Guo Guo

A new nonlinear robust guidance law was proposed by considering autopilot dynamics. Firstly, the mathematic model was built according to relationship between target and missile in vertical plane, by introducing the one-order dynamics of autopilot in Mechanical Engineering. Secondly, the nonlinear terminal guidance was obtained by applying the H∞ control theory under the performance index of minimizing the terminal angular constraint tracking error and control energy, and the asymptotic stability of guidance system was strictly proven by Lyapunov stability theory avoiding the estimation of the time-to-go. Finally, an illustrative example was given to show that the guidance law was more robust and both the impact angle and guidance precision were met in the case of no any target information.

2014 ◽  
Vol 945-949 ◽  
pp. 1493-1499 ◽  
Author(s):  
Lin Ping Feng ◽  
Zuo E Fan ◽  
You Gen Zhang

In order to achieve the tactical mission of cooperative attack for multi-missiles, in a predetermined direction at a predetermined time, this paper studies the design of guidance law with impact angle and impact time constraints. Firstly, using the optimal control theory, the optimal guidance law is designed to control the impact angle, based the relative motion between missile and target. Then the state feedback guidance law is designed to control the arrival impact time, with the application of feedback linearization control theory. Finally, reference the design idea of two-stage guidance system, the anti-ship missile use two different guidance laws in the process of attacking the target. During the first stage, the state feedback guidance law is used to accurately control the impact time and coarsely control the impact angle. During the second stage, the optimal guidance law is used to accurately control the impact angle. And the correctness and effectiveness of the design method is verified by simulation.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Haoqiang Zhang ◽  
Shengjing Tang ◽  
Jie Guo ◽  
Wan Zhang

A two-phased guidance problem with terminal impact angle constraints and seeker’s field-of-view limit is addressed in this paper for a missile against a nonmaneuvering incoming target. From the conventional PN guidance without any constraints, it is found that satisfying the impact angle constraint causes a more curved missile trajectory requiring a large look angle. To avoid the look angle exceeding the seeker’s physical limit, a two-phased look angle control guidance scheme with the terminal constraint is introduced. The PN-typed guidance law is designed for each guidance phase with a specific switching condition of line-of-sight. The proposed guidance law is comprised of two types of acceleration commands: the one in the initial phase which aims at controlling the missile’s look angle to reach the limit and the other for final phase which is produced by switching the navigation gain. The monotonicity of the line-of-sight angle and look angle is analyzed and proved to support the proposed method. To evaluate the specific navigation gains for both initial and final phases, the scaling coefficient between them is discussed by solving a quadratic equation with respect to the initial navigation gain. To avoid a great abrupt acceleration change at the switching instant, a minimum coefficient is chosen. Extensive simulations are performed to validate the efficiency of the proposed approach.


Author(s):  
Min-Guk Seo ◽  
Chang-Hun Lee ◽  
Tae-Hun Kim

A new design method for trajectory shaping guidance laws with the impact angle constraint is proposed in this study. The basic idea is that the multiplier introduced to combine the equations for the terminal constraints is used to shape a flight trajectory as desired. To this end, the general form of impact angle control guidance (IACG) is first derived as a function of an arbitrary constraint-combining multiplier using the optimal control. We reveal that the constraint-combining multiplier satisfying the kinematics can be expressed as a function of state variables. From this result, the constraint-combining multiplier to achieve a desired trajectory can be obtained. Accordingly, when the desired trajectory is designed to satisfy the terminal constraints, the proposed method directly can provide a closed form of IACG laws that can achieve the desired trajectory. The potential significance of the proposed result is that various trajectory shaping IACG laws that can cope with various guidance goals can be readily determined compared to existing approaches. In this study, several examples are shown to validate the proposed method. The results also indicate that previous IACG laws belong to the subset of the proposed result. Finally, the characteristics of the proposed guidance laws are analyzed through numerical simulations.


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.


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.


2018 ◽  
Vol 91 (1) ◽  
pp. 20-29 ◽  
Author(s):  
Jian Hu ◽  
Naigang Cui ◽  
Yuliang Bai ◽  
Yunhai Geng

Purpose The purpose of this paper is to present a novel guidance law that is able to control the impact time while the seeker’s field of view (FOV) is constrained. Design/methodology/approach The new guidance law is derived from the framework of Lyapunov stability theory to ensure interception at the desired impact time. A time-varying guidance gain scheme is proposed based on the analysis of the convergence time of impact time error, where finite-time stability theory is used. The circular trajectory assumption is adopted for the derivation of accurate analytical estimation of time-to-go. The seeker’s FOV constraint, along with missile acceleration constraint, is considered during guidance law design, and a switching strategy to satisfy it is designed. Findings The proposed guidance law can drive missile to intercept stationary target at the desired impact time, as well as satisfies seeker’s FOV and missile acceleration constraints during engagement. Simulation results show that the proposed guidance law could provide robustness against different engagement scenarios and autopilot lag. Practical implications The presented guidance law lays a foundation for using cooperative strategies, such as simultaneous attack. Originality/value This paper presents further study on the impact time control problem considering the seeker’s FOV constraint, which conforms better to reality.


2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Tianning Wang ◽  
Shengjing Tang ◽  
Jie Guo ◽  
Haoqiang Zhang

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.


Author(s):  
Peng Li ◽  
Qi Liu ◽  
Chen-Yu He ◽  
Xiao-Qing Liu

This paper investigates the three-dimensional guidance with the impact angle constraint, actuator faults and input constraint. Firstly, an adaptive three-dimensional guidance law with impact angle constraint is designed by using the terminal sliding mode control and nonhomogeneous disturbance observer. Then, in order to solve the problem of the input saturation and actuator faults, an adaptive anti-saturation fault-tolerant three-dimensional law is proposed by using the hyperbolic tangent function based on the passive fault-tolerant control. Finally, the effectiveness of the designed guidance laws is verified by using the Lyapunov function and simulation.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Shengjiang Yang ◽  
Jianguo Guo ◽  
Jun Zhou

A new integrated guidance and control (IGC) law is investigated for a homing missile with an impact angle against a ground target. Firstly, a control-oriented model with impact angle error of the IGC system in the pitch plane is formulated by linear coordinate transformation according to the motion kinematics and missile dynamics model. Secondly, an IGC law is proposed to satisfy the impact angle constraint and to improve the rapidity of the guidance and control system by combining the sliding mode control method and nonlinear extended disturbance observer technique. Thirdly, stability of the closed-loop guidance and control system is proven based on the Lyapunov stability theory, and the relationship between the accuracy of the impact angle and the estimate errors of nonlinear disturbances is derived from stability of the sliding mode. Finally, simulation results confirm that the proposed IGC law can improve the performance of the missile guidance and control system against a ground target.


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