A non-contact spacecraft architecture with extended stochastic state observer based control for gravity mission

Abstract

A novel non-contact spacecraft architecture with the extended stochastic state observer for disturbance rejection control of the gravity satellite is proposed. First, the precise linear driving non-contact voice-coil actuators are used to separate the whole spacecraft into the non-contact payload module and the service module, and to build an ideal loop with precise dynamics for disturbance rejection control of the payload module. Second, an extended stochastic state observer is enveloped to construct the overall nonlinear external terms and the internal coupled terms of the payload module, enabling the controller design of the payload module turned into the linear form with simple bandwidth-parameterization tuning in the frequency domain. As a result, the disturbance rejection control of the payload module can be explicitly achieved in a timely manner without complicated tuning in actual implementation. Finally, an extensive numerical simulation is conducted to validate the feasibility and effectiveness of the proposed approach.

Low-complexity observer–based output-feedback tracking control for a class of nonlinear lower-triangular systems

“…The system uncertainties always includes the inherent uncertainties and the external disturbances, and how to deal with them is a problem to be considered when designing the controller. Disturbance-observer (DOB)-based control has attracted much attention because of its novelty in concept and superiority in practice Liu et al (2021b). In Fu et al (2018Fu et al ( , 2019, a nonlinear DOB technique was designed to estimate and compensated the external disturbances for the hamiltonian systems.…”

“…The userspecified function, which is known as the prescribed performance function (PPF), is the key to guaranteeing the convergence of the output tracking error within the prescribed regions. In the past few decades, the PPC method has been well studied for nonlinear systems and exhibits expected performance, such as autonomous underwater vehicles (Elhaki and Shojaei, 2020), space robot (Liu et al, 2021a(Liu et al, , 2021b, dynamic positioning of ships (Li et al, 2020), and so on. However, one common feature of the foregoing PPC-based control methods is that the exponential decay functions are typically devoted to construct the performance envelops.…”