Finite-Time Control for Attitude Tracking Maneuver of Rigid Satellite

Abstract

The problem of finite-time control for attitude tracking maneuver of a rigid spacecraft is investigated. External disturbance, unknown inertia parameters are addressed. As stepping stone, a sliding mode controller is designed. It requires the upper bound of the lumped uncertainty including disturbance and inertia matrix. However, this upper bound may not be easily obtained. Therefore, an adaptive sliding mode control law is then proposed to release that drawback. Adaptive technique is applied to estimate that bound. It is proved that the closed-loop attitude tracking system is finite-time stable. The tracking errors of the attitude and the angular velocity are asymptotically stabilized. Moreover, the upper bound on the lumped uncertainty can be exactly estimated in finite time. The attitude tracking performance with application of the control scheme is evaluated through a numerical example.

Finite‐time attitude‐tracking control for rigid spacecraft with actuator failures and saturation constraints

“…The external disturbances vector d , which originates from gravitation, magnetic forces, solar radiation, aerodynamic drags, and so on, is usually unknown. With all these factors considered, the function N (Ω, q ) is nonlinear and uncertain.Remark The prerequisite for dealing with inertial uncertainties and external disturbances in most of the existing achievements is to satisfy some assumptions, for example, the inertial matrix is regarded as known in References , the upper bound of external disturbances is deemed as known in References , the external disturbances and perturbed inertial matrix are assumed to be differentiable in References and , the specific functional relationships between the angular velocity and the lumped unknown nonlinear function should be met as in References , , and so on. We admit that these assumptions have facilitated the controllers design, yet some limitations cannot be ignored, such as the following: (1) the upper bounds of the external disturbances and unknown inertial matrix cannot be easily obtained due to the complexity of the practical spacecraft system, and even if obtained occasionally, they are usually conservative estimates; and (2) some assumptions about specific functional relationships are rigorous because the given expressions are difficult to satisfy or controversial because some variables are treated as constants.…”

“…A modified differentiator‐based adaptive controller was presented in Reference . In Reference , the problem of finite‐time attitude maneuvers for a rigid satellite was investigated via adaptive SMC. The prerequisite for the outstanding achievements in the above‐mentioned literature is a prior knowledge of unknown inertial matrix and external disturbances, for instance, the upper bounds of the external disturbances and inertial matrix are regarded as known in References , and the external disturbances and the perturbed inertial matrix are assumed to be differentiable in References and .…”

“…In Reference , the problem of finite‐time attitude maneuvers for a rigid satellite was investigated via adaptive SMC. The prerequisite for the outstanding achievements in the above‐mentioned literature is a prior knowledge of unknown inertial matrix and external disturbances, for instance, the upper bounds of the external disturbances and inertial matrix are regarded as known in References , and the external disturbances and the perturbed inertial matrix are assumed to be differentiable in References and . By relaxing the requirements of prior knowledge, less constrained attitude controllers were designed in References and , where the upper bounds of unknown functions were estimated by adaptive laws in Reference and a fast TSM (FTSM) manifold was established to cope with uncertainties in Reference .…”

“…The main contributions are summarized as follows. This is the first attempt to combine the FNTSM technique and fuzzy logic system (FLS) to achieve the finite‐time attitude tracking for a rigid spacecraft subject to unknown inertial parameters, external disturbances, completely failed actuators failures, and saturation constraints. A smooth function with stronger saturation approximation ability is presented to deal with the actuator saturation constraints, which is quite different from many literature studies such as References , , , and so on. The attitude‐tracking scheme is more practical and less demanding because the requirement of a prior knowledge of uncertainties in most of the existing achievements (see References , , , to name a few) is removed. Unlike the common fault handling method in References , and , a less conservative approach for tackling actuator failures and saturations is provided through analyzing the uncertain control input amongst different cases. …”

Finite‐time adaptive fault‐tolerant control for rigid spacecraft attitude tracking

“…Among various finite‐time control schemes (e. g. homogeneous method [21], H ∞ fuzzy control [22], adding power integrators [23]), sliding mode control (SMC) is the most widely used due to its strong robustness against external disturbances and internal uncertainties. Related SMC techniques include but are not limited to terminal sliding mode (TSM) [24,25], non‐singular TSM (NTSM) [26,27], full‐order recursive sliding mode [28], and super‐twisting sliding mode [29] some of which have been applied to achieve finite‐time ATC for spacecraft systems [30‐47]. In [35] an adaptive sliding mode controller was designed for the attitude‐tracking maneuver of a rigid satellite.…”