Nonlinear Attitude Control of Flexible Spacecraft With Scissored Pairs of Control Moment Gyros

Author(s):  
Jixiang Fan ◽  
Di Zhou

Dynamic equations describing the attitude motion of flexible spacecraft with scissored pairs of control moment gyroscopes are established. A nonlinear controller is designed to drive the flexible spacecraft to implement three-axis large-angle attitude maneuvers with the vibration suppression. Singularity analysis for three orthogonally mounted scissored pairs of control moment gyros shows that there exists no internal singularity in this configuration. A new pseudo-inverse steering law is designed based on the synchronization of gimbal angles of the twin gyros in each pair. To improve the synchronization performance, an adaptive nonlinear feedback controller is designed for each pairs of control moment gyros by using the stability theory of Lyapunov. Simulation results are provided to show the validity of the controllers and the steering law.

2013 ◽  
Vol 446-447 ◽  
pp. 1160-1164
Author(s):  
Sahar Bakhtiari Mojaz ◽  
Hamed Kashani

Vibration properties of most assembled mechanical systems depend on frictional damping in joints. The nonlinear transfer behavior of the frictional interfaces often provides the dominant damping mechanism in structure and plays an important role in the vibratory response of it. For improving the performance of systems, many studies have been carried out to predict measure and enhance the energy dissipation of friction. This paper presents a new approach to vibration reduction of flexible spacecraft with enhancing the energy dissipation of frictional dampers. Spacecraft is modeled as a 3 degree of freedom mass-spring system which is controlled by a lead compensator and System responses to step function evaluated. Coulomb and Jenkins element has been used as vibration suppression mechanisms in joints and sensitivity of their performance to variations of spacecraft excitation amplitude and damper properties is analyzed. The relation between frictional force and displacement derived and used in optimization of control performance. Responses of system and control effort needed for the vibration control are compared for these two frictional joints. It is shown that attitude control effort reduces, significantly with coulomb dampers and response of system improves. On the other hand, due to stick-slip phenomena in Jenkins element, we couldn’t expect the same performance from Jenkins damper.


2017 ◽  
Vol 89 (6) ◽  
pp. 815-825 ◽  
Author(s):  
Li Fan ◽  
Min Hu ◽  
Mingqi Yang

Purpose The purpose of this paper is to develop a theoretical design for the attitude control of electromagnetic formation flying (EMFF) satellites, present a nonlinear controller for the relative translational control of EMFF satellites and propose a novel method for the allocation of electromagnetic dipoles. Design/methodology/approach The feedback attitude control law, magnetic unloading algorithm and large angle manoeuvre algorithm are presented. Then, a terminal sliding mode controller for the relative translation control is put forward and the convergence is proved. Finally, the control allocation problem of electromagnetic dipoles is formulated as an optimization issue, and a hybrid particle swarm optimization (PSO) – sequential quadratic programming (SQP) algorithm to optimize the free dipoles. Three numerical simulations are carried out and results are compared. Findings The proposed attitude controller is effective for the sun-tracking process of EMFF satellites, and the magnetic unloading algorithm is valid. The formation-keeping scenario simulation demonstrates the effectiveness of the terminal sliding model controller and electromagnetic dipole calculation method. Practical implications The proposed method can be applied to solve the attitude and relative translation control problem of EMFF satellites in low earth orbits. Originality/value The paper analyses the attitude control problem of EMFF satellites systematically and proposes an innovative way for relative translational control and electromagnetic dipole allocation.


2005 ◽  
Vol 128 (3) ◽  
pp. 592-599 ◽  
Author(s):  
Di Zhou ◽  
Tielong Shen ◽  
Katsutoshi Tamura

The slewing motion of a truss arm driven by a V-gimbaled control-moment gyro is studied. The V-gimbaled control-moment gyro consists of a pair of gyros that must precess synchronously. For open-loop slewing motion control, the controller design problem is simplified into finding a feedback controller to steer the two gyros to synchronously track a specific command. To improve the synchronization performance, the integral of synchronization error is introduced into the design as an additional state variable. Based on the second method of Lyapunov, an adaptive nonlinear feedback controller is designed. For more accurate but complicated closed-loop slewing motion control, the feedback linearization technique is utilized to partially linearize the nonlinear nominal model, where two specific output functions are chosen to satisfy the system tracking and synchronization requirements. The system tracking dynamics are bounded by properly determining system indices and command signals. For the partially linearized system, the backstepping tuning function design approach is employed to design an adaptive nonlinear controller. The dynamic order of the adaptive controller is reduced to its minimum. The performance of the proposed controllers is verified by simulation.


2005 ◽  
Vol 29 (3) ◽  
pp. 389-402 ◽  
Author(s):  
Aaron Muise ◽  
Robert J. Bauer

Control Moment Gyroscopes (CMGs) have typically been used for attitude control of satellites. This paper extends the application of CMGs to regulate vibrations in the flexible appendages of orbiting spacecraft using a novel double- and single-gimbaled CMG prototype design. System Identification and control experiments were carried out to compare the effectiveness of this new CMG to regulate lightly damped, low frequency vibrations in a single flexible rib. Experimental results conclude that the CMG can be effectively used to regulate vibrations in flexible structures and, for equivalent values of gyricity and disturbance, the double-gimbaled CMG performance can be two to three times more effective and independent of the direction of applied disturbance.


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