Fixed time coordinated attitude tracking control of multi spacecraft based on disturbance observer

DOI:	10.11809/bqzbgcxb2024.01.034
Keywords:	multi spacecraft; disturbance observer; coordinated attitude tracking; Fixed time consensus; sliding mode control
Abstract:	To address the problem of attitude consensus tracking in multi spacecraft systems under disturbance, a distributed coordinated attitude control strategy is proposed based on disturbance observer and the Fixed time theory. The Multi spacecraft system are susceptible to external disturbance such as solar radiation pressure, gravity gradient, and geomagnetic forces in space, leading to a decrease in control accuracy. Additionally, the impact of inertia uncertainties in spacecraft cannot be ignored. To address these challenges, a disturbance observer based on second order integral sliding mode is designed to rapidly and accurately estimate compound disturbance, and this observer does not require any prior information about disturbance. By utilizing the estimated values from the observer and the leader following method, a distributed Fixed time coordinated attitude controller is proposed to achieve Fixed time convergence of the system, with the convergence time adjustable through control parameters. The Fixed time stability of the system is proven by using Lyapunov functions. Simulation and comparative experimental results demonstrate that the disturbance observer can accurately estimate compound disturbance in a short time. The coordinated controller achieves robust tracking of desired attitudes within fixed time. In comparison to the adaptive finite time method, this control strategy exhibits higher precision, faster convergence, and lower fuel consumption.
Published:	2024-01-28
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