A Lagrangian Dynamic Model and Controller for a Space Tether System

Abstract

The present invention relates to a Lagrange dynamic model of a space tether system and a controller. Aiming at the modeling problem of the space tether system, six parameters consisting of three attitude angles, a tether surface internal angle, a tether surface external angle, the tether length and the like are considered, the Lagrangian method is employed to detailedly deduce the generalized force model of the tether, and a generalized state stability controller is designed. The Lagrange dynamic model of space tether system and the controller can solve the tether system target attitude modeling problem when a platform is equivalent to the target quality; and the designed controller can realize the control of the tether system generalization state variables after target capture.

Description

technical field [0001] The invention belongs to the field of tether system control, and relates to a Lagrangian dynamic model and a controller of a space tether system. Background technique [0002] The space tether system is a new type of space torsion system formed by connecting the space platform with the space shuttle, spacecraft, space station or other satellites, and grabbers (flying claws, flying spears, flying tongues, flying nets, etc.) through flexible tethers. Flexible assembly, the length of this flexible assembly can reach hundreds of meters or even hundreds of kilometers. The tether system has a wide range of uses and application prospects, and can be widely used in space experiments, space transportation, space junk cleanup, rescue of failed satellites, and regeneration of geostationary orbit stations. The space tether system consists of three parts: space platform, space tether and target. The precise modeling of the tether system can reflect the essential ...

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Problems solved by technology

[0003] At present, there are several modeling methods for tethered systems as follows: 1), Misra, Z.H.Zhu, H.Wen, etc. regard the tethered satellite system as a two-body particle problem, and only consider the in-plane and surface The outer angle and tether length are three parameters, depending on the tether length is several kilometers or even hundreds of kilometers, it is not applicable to the situation where the tether length is hundreds of meters, and it cannot reflect the attitude angle of the tethered satellite; 2), Liu Yingying and others consider Based on the attitude of the sub-star, the kinematics and dynamics model of the 100-meter-level tether system was established, and six parameters including the three attitude angles of the sub-star, the in-plane and out-of-plane angles of the tether, and the length of the tether were considered. The model method assumes that the mass of the sub-star is much smaller than that of the main star, and the attitude movement of the tether and the sub-star does not affect the orbit of the system; 4), Wang Dongke et al. established a complex Lagrangian dynamics model of the tethered robot system, and the length of the tether is 100 At the meter level, six parameters including the three attitude angles of the tethered robot, the in-plane and out-of-plane angles of the tether, and the length of the tether are considered. The prerequisite for the establishment of this modeling method is that the mass of the space platform is much greater than that mass, but when the mass of the space platform is equal to the mass of the target, this modeling method is no longer valid; 5), Zhang Fan et al. established a Lagrangian dynamic model when the mass of the target and the platform are equal, and the length of the tether is 100 meters level, considering the yaw angle, pitch angle, tether in-plane angle, out-of-plane angle, and tether length of the target and the platform, but the roll angle of the target is not considered

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