Extended state observer-based finite-time guidance laws on account of thruster dynamics

Abstract

Guidance laws are designed for a near space interceptor with line-of-sight angle as input and on–off type thrust as output. The dynamics of thruster is viewed as a first-order lag with on–off working style and is integrated with the target–interceptor engagement dynamics to design bang-bang type sliding mode guidance laws. An extended state observer is designed to estimate the line-of-sight angular rate and the acceleration of target with the line-of-sight angle as a measurement. It is rigorously proved that the states of guidance system converge to a neighborhood of sliding mode in finite time and the line-of-sight angular rate converges to a neighborhood of the origin along the sliding mode in finite time under the designed guidance laws. Furthermore, in order to reduce the switching frequency of thruster, a sliding mode guidance law with hysteresis-band according to the sufficient condition for finite time convergence is proposed. Then, it is integrated with the bang-bang type sliding mode guidance law to yield a composite guidance law. Simulation results show that the extended state observer can effectively estimate the line-of-sight angular rate and the target acceleration, and the proposed sliding mode guidance laws have better performance than typical proportional guidance law.

A Novel Guidance Law for Intercepting a Highly Maneuvering Target

“…Substitute Equation ( 29) into Equation (31), and the following equation is obtained. (32), and the following equation is obtained.…”

“…In recent years, with the development of disturbance observer techniques, the sliding mode control and disturbance observer techniques are usually combined in the guidance system design. The techniques of disturbance and uncertain observers, such as nonlinear disturbance observer [26], the nonhomogeneous disturbance observer with finitetime convergence [2], the fixed-time convergence disturbance observer [27], the extended high gain observer [28], the robust nonlinear disturbance observer [29], the extended state observer [30][31][32], and nonlinear robust H-infinity observers [33], combined with the sliding mode control, have made important contributions to the treatment of many uncertain disturbances and improve the robustness of the guidance system. However, the convergence rate of the aforementioned observers is mainly determined by the magnitude of the gains, and the transient process of the observers may adversely affect the performance of the guidance system.…”

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

“…So far, the techniques of disturbance and uncertainty estimation such as nonlinear disturbance observer [30], nonhomogeneous disturbance observer with finite time convergence [31], fixed-time convergence disturbance observer [32], extended high gain observer [33], robust nonlinear disturbance observer [34], extended state observer [35, 36, 37] and nonlinear robust H-infinity observers [38], have made important contributions to the treatment of many uncertain disturbances in guidance systems.…”