Decoupled Finite-Time Approximation Auxiliary System-Based Three-Dimensional Integrated Guidance and Control

In this paper, to develop a backstepping-based finite-time control (BFTC) method for the three-dimensional integrated guidance and control (IGC) system with target maneuvers and disturbances, a novel decoupled finite-time approximation auxiliary system (DFTAAS) is proposed together with a finite-time disturbance observer (FTDO). To accurately estimate the target maneuvers and the disturbances, the FTDO is designed. To approximate the virtual control law derivative and avoid the explosion of complexity problem, the DFTAAS is proposed. To solve the singularity issue and guarantee the boundedness of the virtual control law derivative, the piecewise functions are designed to derive the DFTAAS and the virtual control. Besides, to make the controller parameters independent of the norms associated to the control matrices, the control matrices are introduced into the DFTAAS so that the conservatism of the controller parameters is restrained. Furthermore, the finite-time stability properties of the system state stabilization and the disturbance estimation are integrated into the Lyapunov stability to guarantee the finite-time stability of the whole closed-loop IGC system. Finally, the hardware-in-the-loop experiment is implemented to verify the effectiveness of the proposed method. Note to Practitioners—The aim of this paper is to design a BFTC scheme for the three-dimensional IGC system with target maneuvers and disturbances. In the practical IGC application, to solve the explosion of complexity problem, the finite-time dynamic surface control is designed to implement the BFTC. Nevertheless, the boundedness of the virtual control law derivative, which is essential for the system stability, can not be guaranteed due to the singularity. Besides, the parameter conservatism is inevitable due to the control matrices. In addition, the finite-time stability properties of the system state stabilization and the disturbance estimation, which interact and influence each other in the control process, is rarely integrated in practical. In view of the above actual issues, the piecewise function is designed to develop the DFTAAS and the guidance law to solve the explosion of complexity problem and ensure the boundedness of the virtual control law derivative. The control matrices are introduced into the DFTAAS to solve the problem of parameter conservatism. The finite-time stability properties of the system state stabilization and the disturbance estimation are integrated into the Lyapunov stability, which is more in line with the practical needs to sufficiently consider the coupling of them.