Fixed-time relative attitude and orbit tracking control method under error constraint

Abstract

The invention relates to a fixed-time relative attitude and orbit tracking control method under error constraint. Aiming at the particularity of a space rendezvous and docking task, the time when a relative orbit and attitude tracking error converges to a steady-state boundary constraint range is explicitly given by a fixed time stability concept, namely, the convergence time is preset. Meanwhile, compared with a traditional preset performance control method, it can be guaranteed that the relative attitude and orbit tracking error has expected dynamic and steady-state performance without an error transformation function, and meanwhile, a nonlinear disturbance observer is designed to estimate and compensate composite uncertainty such as system uncertainty and external disturbance so as to improve system robustness. The designed controller has high control precision and response speed, and meets the requirements of actual rendezvous and docking tasks on relative state constraint and convergence time constraint.

Description

technical field [0001] The invention relates to a fixed-time relative attitude-orbit tracking control method under error constraints, and belongs to the technical field of spacecraft control. Background technique [0002] With the continuous development of aerospace technology, the space tasks undertaken by spacecraft are becoming more and more complex. Good relative orbit and attitude tracking performance is the prerequisite and guarantee for completing rendezvous and docking tasks such as on-orbit maintenance and space observation. In actual engineering, there are many issues to be considered in the relative orbit and attitude cooperative control problem. First of all, the relative orbit and attitude tracking system is a nonlinear system with multiple inputs and multiple outputs, and due to the characteristics of pose and pose coupling, it is often difficult to obtain an accurate dynamic model. In addition, the spacecraft mass and Parameters such as moment of inertia are ...

AI Technical Summary

Problems solved by technology

First of all, the relative orbit and attitude tracking system is a nonlinear system with multiple inputs and multiple outputs, and due to the characteristics of pose coupling, its accurate dynamic model is often difficult to obtain. In addition, the spacecraft mass and Parameters such as moment of inertia are uncertain, and it is difficult to accurately measure and estimate

On the other hand, due to the complexity of the space environment, the spacecraft in orbit will inevitably be affected by external disturbances such as solar light pressure, gravity gradient and aerodynamic drag, and it is difficult to obtain accurate models of these disturbances

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