A Non-cooperative Spacecraft Attitude Estimation Method Based on Virtual Sliding Mode Control

Abstract

The invention discloses a non-cooperative spacecraft attitude estimation method based on virtual sliding mode control, and belongs to the technical field of non-cooperative spacecraft navigation. The non-cooperative spacecraft attitude estimation method comprises the following steps: utilizing a virtual control sliding mode controller based on the Lyapunov principle; using target satellite absolute attitude obtained by a stereoscopic vision system as a control objective; according to motion characteristics of the target satellite, establishing a virtual satellite motion model of the target satellite; using a kinetic model of the virtual satellite as a controlled member to obtain attitude parameters of the virtual satellite; using attitude parameters estimated by the virtual satellite and the target satellite absolute attitude obtained by the stereoscopic vision system as controlled input, and calculating the virtual revolving moment on the motion model of the virtual satellite through the virtual sliding mode controller, so as to realize the estimation of the target satellite attitude parameters by the virtual control sliding mode controller. The non-cooperative spacecraft attitude estimation method disclosed by the invention is low in calculated amount, and can still achieve higher convergence rate and higher precision when the initial error of the state variables is high or the system error emerges, so as to meet the requirements of the high performance navigation system.

Description

technical field [0001] The invention relates to a satellite attitude tracking method based on virtual sliding mode control, and belongs to the technical field of non-cooperative spacecraft navigation. Background technique [0002] Compared with non-cooperative spacecraft, the free, dexterous and reliable flight capability of spacecraft has great scientific and application value at a very short distance, and has attracted the attention of all countries in the world. [0003] The so-called non-cooperative target means that the target satellite itself is not equipped with a docking pattern mark and a docking port / capture hook, or its attitude and orbit are uncontrollable and it rolls freely in space. It cannot provide navigation information such as effective position and attitude, and cannot control itself. A key technology that needs to be solved for the autonomous approach, hovering and acquisition of non-cooperative target satellites in space is the real-time relative posit...

AI Technical Summary

Problems solved by technology

[0006] At present, some domestic scholars have made some achievements in the attitude estimation of short-distance non-cooperative spacecraft based on stereo vision. In the case of only obtaining the appearance characteristics and some static parameters of the main star, the relative position and attitude can be determined independently, but There are also some ideal assumptions. For example, the derived model discusses the coincidence of the target satellite’s own system and the orbital system; and the classical filtering method has high requirements on the accuracy of the model. When the initial error is large, there is an estimated The problem of sharp decline in effect and slow convergence of the filter, and the need to update the state covariance matrix during the iterative process, the amount of calculation is large

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