Distributed adaptive neural network fixed‐time leader‐follower attitude consensus control for multiple rigid spacecraft

Abstract

In this paper, the problem of fixed-time attitude consensus control is addressed for a group of rigid spacecraft in the presence of inertia uncertainties and external disturbances. By applying the adaptive technique and neural network approximation technique to handle the disturbances and uncertainties, an adaptive neural network-based distributed protocol is proposed to achieve attitude consensus control for multiple rigid spacecraft. The proposed distributed attitude consensus protocol is composed of a group of distributed fixed-time observers for followers to estimate the leader's information and an adaptive neural network-based fixed-time sliding mode control law to realize attitude tracking control. Rigorous proofs are provided to demonstrate that the estimation errors of the proposed observers are convergent in a fixed time. Further, it is also proven that attitude tracking errors reach some adjustable regions in a fixed time under the proposed attitude consensus protocol. Numerical simulations are conducted to illustrate the performance of the proposed distributed attitude consensus protocol.

Fixed‐time adaptive fault‐tolerant tracking control for uncertain strict‐feedback nonlinear systems via command filtered backstepping

“…Many fixed-time control laws have been developed for various nonlinear systems during the past few years. [29][30][31] Recently, a distinctive adaptive fixed-time tracking control law was proposed via CFB for strict-feedback nonlinear systems in Reference 32. It should be mentioned that the command filters utilized in Reference 32 are first-order Levant differentiators, which can guarantee only the finite-time estimation performance.…”

“…Fortunately, the fixed‐time control, which was firstly proposed in References 28, guarantees that the settling time is only dependent on the designed parameters of the closed‐loop system and has nothing to do with the initial conditions. Many fixed‐time control laws have been developed for various nonlinear systems during the past few years 29–31 . Recently, a distinctive adaptive fixed‐time tracking control law was proposed via CFB for strict‐feedback nonlinear systems in Reference 32.…”

Reinforcement learning‐based adaptive predefined‐time optimal tracking control for strict‐feedback nonlinear systems

“…The topics concerning nonlinear control 1,2 have garnered considerable interest during the past decades. In the practical system dynamics, numerous nonlinear systems can be depicted as strict-feedback nonlinear structures, such as spacecraft attitude control systems, 3,4 robotic systems, 5,6 and unmanned aerial vehicle attitude systems. 7,8 One of the dominant control strategies employed in such systems is the backstepping technique.…”