Finite-time guidance laws for three-dimensional missile-target interception

Abstract

In this paper, three-dimensional terminal guidance problem of a missile intercepting a maneuvering target is studied by using a composite control scheme based on finite-time control and nonlinear disturbance observer technique. The threedimensional model is characterized by nonlinear interception geometry, which the azimuth angle and elevation angle are coupled with each other. Many existing results are studied for planar model which ignores the coupled terms of threedimensional model. In this paper, the coupled terms of guidance system can well be solved by selecting a special Lyapunov function, and guidance laws with finite-time convergence characteristic are derived, which have the ability to track target maneuver. Based on sliding mode control method, discontinuous switching functions are involved as augmented terms to suppress the target accelerations which are regarded as unknown bounded external disturbance of guidance systems. To improve the disturbance rejection performance of guidance system, the gains of switching functions are selected to be larger than the bounds of accelerations. However, the guidance system could generate the chattering phenomenon caused by discontinuous switching functions. To handle the chattering problem, nonlinear disturbance observers are constructed to estimate the target accelerations. The estimated target accelerations are introduced into the finite-time guidance laws and used as the feedforward compensation terms to reject the actual target accelerations. This is an efficient approach to suppress the chattering phenomenon. Then, novel composite guidance laws are presented based on finite-time feedback control and disturbance feedforward compensation. Finally, simulation results on three-dimensional missile-target interception examples are provided to demonstrate the effectiveness of the proposed approaches.

Profile-Tracking-Based Adaptive Guidance Law against Maneuvering Targets

“…It is known that the way to introduce a switching term easily brings about chattering. Then, estimation and adaptive control theories are adopted to deal with target maneuver in [22][23][24][25][26][27][28][29]. A nonhomogeneous disturbance observer was used to estimate disturbances in a guidance system, and the chattering was eliminated in [22].…”

“…However, the finite-time stability theory was no longer strictly satisfied due to the presence of an estimation error. Based on the finite-time stability theory and a nonlinear disturbance observer, Zhang et al [24] presented a composite guidance law where the gain of the switching term was reduced to being only larger than the upper bound of a disturbance estimation error. The finite-time convergent characteristic of the LOSR was proven under the composite law.…”

“…In [25], a finite-time guidance law was given without the bound knowledge of a disturbance estimation error by an adaptive exponential reaching law. Different from the observer method in [22][23][24][25][26][27] considered the target maneuver as a disturbance with unknown bound and employed an adaptive algorithm to approach the bound. Furthermore, the proposed controllers for a guidance system were inherently continuous by substituting the saturation function for the sign function and asymptotically converged to the origin in theory in spite of the substitution.…”

Composite Finite‐time Convergent Guidance Law for Maneuvering Targets with Second‐order Autopilot Lag

“…In this regard, target acceleration has been frequently regarded as external disturbance and compensated as feedforward term. Disturbance observer (DOB) is a well‐known approach used to estimate disturbance of the system and improve the performance of the controller . In , a guidance law is designed based on the integral sliding mode control method, and a nonlinear DOB is used to eliminate the influence of target maneuvers.…”

“…Disturbance observer (DOB) is a well‐known approach used to estimate disturbance of the system and improve the performance of the controller . In , a guidance law is designed based on the integral sliding mode control method, and a nonlinear DOB is used to eliminate the influence of target maneuvers. A formulation of terminal guidance law for a missile intercepting maneuvering target is investigated in ; in this study, a nonlinear DOB is employed to improve the system's performance and avoid the chattering phenomenon.…”