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Debasish Ghose - One of the best experts on this subject based on the ideXlab platform.

  • three dimensional Impact Angle guidance with coupled engagement dynamics
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2017
    Co-Authors: Shashi Ranjan Kumar, Debasish Ghose
    Abstract:

    This paper proposes three-dimensional Impact Angle control guidance laws based on a sliding mode control technique. Unlike the usual approach of decoupling the engagement dynamics into two mutually orthogonal two-dimensional planes, the guidance laws are derived using coupled engagement dynamics. By using this approach, the control effort required to achieve the objective reduces and the performance of the guidance law is improved. The derivations of guidance laws are done using both conventional as well as nonsingular terminal sliding mode control, which guarantees asymptotic and finite time convergence, respectively, to the desired Impact Angle. In order to derive the guidance laws, multi-dimensional switching surfaces are used. The stability of the system, with selected switching surfaces, is demonstrated using Lyapunov stability theory. Numerical simulation results are presented to validate the proposed guidance laws for constant speed, as well as a realistic interceptor model with given aerodynamic properties. The simulations show the advantage of using coupled dynamics. The robustness of the proposed guidance laws, with respect to the interceptor's system lag, is also investigated.

  • Nonlinear Differential Games-Based Impact-Angle-Constrained Guidance Law
    Journal of Guidance Control and Dynamics, 2015
    Co-Authors: Rajarshi Bardhan, Debasish Ghose
    Abstract:

    The problem of intercepting a maneuvering target at a prespecified Impact Angle is posed in nonlinear zero-sum differential games framework. A feedback form solution is proposed by extending state-dependent Riccati equation method to nonlinear zero-sum differential games. An analytic solution is obtained for the state-dependent Riccati equation corresponding to the Impact-Angle-constrained guidance problem. The Impact-Angle-constrained guidance law is derived using the states line-of-sight rate and projected terminal Impact Angle error. Local asymptotic stability conditions for the closed-loop system corresponding to these states are studied. Time-to-go estimation is not explicitly required to derive and implement the proposed guidance law. Performance of the proposed guidance law is validated using two-dimensional simulation of the relative nonlinear kinematics as well as a thrust-driven realistic interceptor model.

  • Nonsingular Terminal Sliding Mode Guidance with Impact Angle Constraints
    Journal of Guidance Control and Dynamics, 2014
    Co-Authors: Shashi Ranjan Kumar, Sachit Rao, Debasish Ghose
    Abstract:

    Guidance laws based on a conventional sliding mode ensures only asymptotic convergence. However, convergence to the desired Impact Angle within a finite time is important in most practical guidance applications. These finite time convergent guidance laws suffer from singularity leading to control saturation. In this paper, guidance laws to intercept targets at a desired Impact Angle, from any initial heading Angle, without exhibiting any singularity, are presented. The desired Impact Angle, which is defined in terms of a desired line-of-sight Angle, is achieved in finite time by selecting the interceptor's lateral acceleration to enforce nonsingular terminal sliding mode on a switching surface designed using nonlinear engagement dynamics. Numerical simulation results are presented to validate the proposed guidance laws for different initial engagement geometries and Impact Angles. Although the guidance laws are designed for constant speed interceptors, its robustness against the time-varying speed of interceptors is also evaluated through extensive simulation results.

  • terminal Impact Angle constrained guidance laws using variable structure systems theory
    IEEE Transactions on Control Systems and Technology, 2013
    Co-Authors: Sachit Rao, Debasish Ghose
    Abstract:

    In this brief, variable structure systems theory based guidance laws, to intercept maneuvering targets at a desired Impact Angle, are presented. Choosing the missile's lateral acceleration (latax) to enforce sliding mode, which is the principal operating mode of variable structure systems, on a switching surface defined by the line-of-sight Angle leads to a guidance law that allows the achievement of the desired terminal Impact Angle. As will be shown, this law does not ensure interception for all states of the missile and the target during the engagement. Hence, additional switching surfaces are designed and a switching logic is developed that allows the latax to switch between enforcing sliding mode on one of these surfaces so that the target can be intercepted at the desired Impact Angle. The guidance laws are designed using nonlinear engagement dynamics for the general case of a maneuvering target.

  • Impact Angle Constraint Guidance Law using Cubic Splines for Intercepting Stationary Targets
    AIAA Guidance Navigation and Control Conference, 2012
    Co-Authors: Ashwin Dhabale, Debasish Ghose
    Abstract:

    In this paper the cubic spline guidance law is presented for intercepting a stationary target at a desired Impact Angle. The guidance law is obtained from cubic spline curve based trajectory using an inverse method. The cubic spline t rajectory curve expresses the altitude as a cubic polynomial of the downrange. The guidance law is modified to achieve interception in the cases where Impact Angle is greater that or equal to 90◦. The guidance law is implemented in a feedback mode to maintain the desired Impact Angle and to reduce miss distance in the presence of lateral acceleration saturation and atmospheric distur- bances. The simulation results show that the guidance law fulfills all the requirements.

Zengqiang Chen - One of the best experts on this subject based on the ideXlab platform.

  • Practical Solution to Impact Angle Control in Vertical Plane
    Journal of Guidance Control and Dynamics, 2014
    Co-Authors: Mingwei Sun, Shengzhi Du, Zengqiang Chen, Qi Xu, Dexian Zhang
    Abstract:

    Impact Angle control shapes the trajectories of antiship and antitank missiles to increase warhead effectiveness and survivability against missile defense systems. The guidance law design with specific Impact direction has been a hot topic in the past four decades. Kim and Grider [1] were pioneers in this field. Since then, many algorithms have emerged to achieve a common objective. Optimal control is the most popular tool used to solve this problem [1–4]. Unfortunately, the range between missile and target is necessary for all these methods. Therefore, these optimal guidance laws cannot be directly applied to the missiles with passive seekers, such as infrared or optical ones. Although the Kalman-type filter can estimate the range [5], it is time consuming to tune suitable parameters and hard to implement in reality. Adding extra compensation terms to the traditional proportional navigation or the biased proportional navigation provides another possibility of controlling the Impact Angle [6]. The result of Kim andGrider [1] also falls within this category. Nevertheless, both of [1] and [6] rely on the range information. Lu et al. [7] proposed an adaptive proportional navigation to achieve the specific Impact Angle without the range information. Ratnoo and Ghose [8,9] developed this idea further to capture all possible Impact Angles in a surface-to-surface planar engagement. The recent Note of [10] presented a two-phase biased proportional navigation to achieve Impact Angle control in the absence of the range information, too. However, the methods in [7–10] are all based on the line-of-sight rate; they may encounter a critical difficulty when employed in low-cost air-to-ground or antiship missiles equipped with a strap-down seeker for measuring the needed information. This is because the line-of-sight rate must be calculated from noisy data since it is not available directly. In addition, the signal-to-noise ratio of the line-of-sight rate for the airto-ground or antiship missiles is rather low on account of the weak maneuverability of the target. The poor quality of line-of-sight rate degrades the feasibility of these approaches because the homing loop with high proportional gainwill be quite sensitive to themeasurement noises and even may be destabilized by the most serious unwanted feedback paths between the angular rates of the missile and the lineof-sight rate. Therefore, to lower the effect of the line-of-sight rate, an alternative way beyond the framework of proportional navigation should be investigated toward a true passive guidance law with Impact Angle constraints. In this Note, a passive guidance law against surface targets only with the line-of-sight information is proposed first, and the theoretical analysis proves that it can achieve the specified Impact Angle with the appropriate handover from the midcourse phase to the terminal guidance phase. Its relationship with the adaptive proportional navigation is then revealed. To raise the Impact accuracy of the guidance law, the line-of-sight rate is incorporated by introducing the autopilot dynamics based on the traditional threeloop acceleration control structure. The recursive least-squares method is employed to estimate the time constant of autopilot online to check aerodynamic uncertainties. The adjoint analysis is employed to investigate the essence behind the precision improvement. The proposed method demonstrates its effectiveness in the comparative simulations.

  • finite time convergent guidance law with Impact Angle constraint based on sliding mode control
    Nonlinear Dynamics, 2012
    Co-Authors: Yunxi Zhang, Mingwei Sun, Zengqiang Chen
    Abstract:

    In this paper, a finite-time convergent sliding-mode guidance law with terminal Impact Angle constraint is presented. The guidance law insures that the line-of-sight angular rate will converge to zero before the final time of the guidance process. Meanwhile the flight-path Angle will meet the terminal Impact Angle requirement. Based on the finite-time convergence stability theory and the variable structure control theory, the finite convergence time is determined. Finally, the simulation results show that the guidance law is effective.

Min-jea Tahk - One of the best experts on this subject based on the ideXlab platform.

  • range to go weighted optimal guidance with Impact Angle constraint and seeker s look Angle limits
    IEEE Transactions on Aerospace and Electronic Systems, 2016
    Co-Authors: Bonggyun Park, Taehun Kim, Min-jea Tahk
    Abstract:

    In this paper, an Impact Angle control guidance law, which considers simultaneously the Impact Angle and seeker's look Angle constraints, is proposed for a constant speed missile against a stationary target. An optimal control theory with state variable inequality constraint is used to design the guidance law, for which a control energy performance index with the weighting function of the range-to-go is minimized. Various forms of guidance and trajectory shaping are possible by selecting a proper gain of the weighting function. To handle the seeker's look Angle limits when the missile trajectory is highly curved by controlling the Impact Angle, the proposed guidance law generates three types of acceleration commands as the guidance phases: the first acceleration command for an initial guidance phase makes an initial seeker's look Angle reach the maximum look Angle; the second one for a midguidance phase maintains the maximum look Angle; the final one for a terminal guidance phase intercepts the target with the desired Impact Angle. The performance of the proposed guidance law was investigated with nonlinear simulations for various engagement conditions.

  • Impact Angle constrained sliding mode guidance against maneuvering target with unknown acceleration
    IEEE Transactions on Aerospace and Electronic Systems, 2015
    Co-Authors: Dongsoo Cho, H. Jin Kim, Min-jea Tahk
    Abstract:

    In this paper, a sliding mode guidance law for Impact Angle control is proposed against a maneuvering target with unknown acceleration, which is capable of achieving the acceptable miss distance and a wide range of the desired Impact Angle. The main idea is to separate the switching surfaces for the Impact Angle constraint and the homing constraint, then to associate the two surfaces by introducing an appropriate virtual controller. Because of the unknown target acceleration, an adaptive procedure is designed to select the gain of the switching controller which accounts for the uncertainty bound regarding the target acceleration. The stability of the proposed approach is analyzed by Lyapunov theory, and the capturability analysis is also presented. Simulation results confirm the effectiveness of the proposed guidance against a maneuvering target as well as a nonmaneuvering target with absence and presence of noise.

  • optimal Impact Angle control guidance law considering the seeker s field of view limits
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2013
    Co-Authors: Bonggyun Park, Min-jea Tahk
    Abstract:

    A new optimal guidance problem with Impact Angle constraint and seeker’s field-of-view limits is investigated for a missile with a strapdown seeker. Impact Angle control to satisfy the terminal fli...

  • design of Impact Angle control guidance laws via high performance sliding mode control
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2013
    Co-Authors: Changhun Lee, Taehun Kim, Min-jea Tahk
    Abstract:

    In this article, a new Impact Angle control guidance law for a stationary or slowly moving target is developed using the high-performance sliding mode control methodology. The law can produce vario...

  • Optimal Impact Angle control guidance law considering the seeker’s field-of-view limits:
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2012
    Co-Authors: Bonggyun Park, Taehun Kim, Min-jea Tahk
    Abstract:

    A new optimal guidance problem with Impact Angle constraint and seeker’s field-of-view limits is investigated for a missile with a strapdown seeker. Impact Angle control to satisfy the terminal fli...

Yao Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Time-varying sliding mode guidance scheme for maneuvering target interception with Impact Angle constraint
    Journal of the Franklin Institute, 2018
    Co-Authors: Xiangdong Liu, Zhuoyue Song, Yao Zhao
    Abstract:

    Abstract In this paper, a guidance scheme for Impact Angle control against maneuvering targets with unknown target acceleration is proposed. In this scheme, the unknown target acceleration is estimated via a linear extended state observer; a novel time-varying global slide mode control technique is presented to eliminate the reaching phase and enforce a desired Impact Angle exactly at the time of interception with finite-time convergence, good robustness, high precision and smooth guidance command. Moreover, feasible guidance logics are developed to achieve all-aspect interception with the tolerance of large initial heading errors. Numerical simulations in various scenarios are performed to verify the performance of the proposed guidance scheme.

Jiang Wang - One of the best experts on this subject based on the ideXlab platform.

  • Generalized optimal Impact-Angle-control guidance with terminal acceleration response constraint:
    Proceedings of the Institution of Mechanical Engineers Part G: Journal of Aerospace Engineering, 2017
    Co-Authors: Hui Wang, Jiang Wang, Defu Lin
    Abstract:

    To study the optimal Impact-Angle-control guidance problem with multiple terminal constraints, a generalized optimal Impact-Angle-control guidance law with terminal acceleration response constraint...

  • Adaptive backstepping Impact Angle control with autopilot dynamics and acceleration saturation consideration
    International Journal of Robust and Nonlinear Control, 2017
    Co-Authors: Wei Wang, Jiang Wang
    Abstract:

    Summary This paper presents a robust Impact Angle constraint guidance law for maneuvering target interception in the presence of autopilot dynamics and input saturation. The presented guidance law is designed on the basis of a combination of adaptive backstepping control technique and higher-order sliding mode differentiator. Different from existing Impact Angle constraint guidance law using sliding mode control, the line-of-sight angular rate and Impact Angle tracking error are regulated by two different virtual control laws. Because the future course of action of the target, an independent entity, cannot be predicted beforehand, adaptive laws are introduced in guidance law derivation for disturbance rejection. Unlike dynamic surface control approach, higher-order sliding mode differentiator is adopted here as an alternative way to obtain the derivatives of the virtual control laws, thus leading to the exact tracking performance of backstepping control. Detailed stability analysis shows that both the line-of-sight angular rate and Impact Angle error can be stabilized in a small region around zero asymptotically. Simulation results explicitly show that accurate interception is achieved with a wide range of Impact Angles. Copyright © 2017 John Wiley & Sons, Ltd.