Dynamics and Control of Spacecraft With a Generalized Model of Variable Speed Control Moment Gyroscopes

The attitude dynamics model for a spacecraft with a variable speed control moment gyroscope (VSCMG) is derived using the principles of variational mechanics. The resulting dynamics model is obtained in the framework of geometric mechanics, relaxing some of the assumptions made in prior literature on control moment gyroscopes (CMGs). These assumptions include symmetry of the rotor and gimbal structure, and no offset between the centers of mass of the gimbal and the rotor. The dynamics equations show the complex nonlinear coupling between the internal degrees-of-freedom associated with the VSCMG and the spacecraft base body's rotational degrees-of-freedom. This dynamics model is then further generalized to include the effects of multiple VSCMGs placed in the spacecraft base body, and sufficient conditions for nonsingular VSCMG configurations are obtained. General ideas on control of the angular momentum of the spacecraft using changes in the momentum variables of a finite number of VSCMGs are provided. A control scheme using a finite number of VSCMGs for attitude stabilization maneuvers in the absence of external torques and when the total angular momentum of the spacecraft is zero is presented. The dynamics model of the spacecraft with a finite number of VSCMGs is then simplified under the assumptions that there is no offset between the centers of mass of the rotor and gimbal, and the rotor is axisymmetric. As an example, the case of three VSCMGs with axisymmetric rotors, placed in a tetrahedron configuration inside the spacecraft, is considered. The control scheme is then numerically implemented using a geometric variational integrator (GVI). Numerical simulation results with zero and nonzero rotor offset between centers of mass of gimbal and rotor are presented.

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Design of an Adaptive Singularity-Free Control Moment Gyroscope (ASCMG) Cluster for Spacecraft Attitude Control

Volume 1: Adaptive and Intelligent Systems Control; Advances in Control Design Methods; Advances in Non-Linear and Optimal Control; Advances in Robotics; Advances in Wind Energy Systems; Aerospace Applications; Aerospace Power Optimization; Assistive Robotics; Automotive 2: Hybrid Electric Vehicles; Automotive 3: Internal Combustion Engines; Automotive Engine Control; Battery Management; Bio Engineering Applications; Biomed and Neural Systems; Connected Vehicles; Control of Robotic Systems ◽

10.1115/dscc2015-9818 ◽

2015 ◽

Cited By ~ 1

Author(s):

Sasi Prabhakaran Viswanathan ◽

Amit K. Sanyal

Keyword(s):

Angular Momentum ◽

Finite Number ◽

Attitude Control ◽

Degrees Of Freedom ◽

Spacecraft Attitude ◽

Spacecraft Attitude Control ◽

Dynamics Model ◽

Control Moment Gyroscope ◽

Control Moment ◽

Control Scheme

Spacecraft attitude control using an Adaptive Singularity-free Control Moment Gyroscope (ASCMG) cluster design for internal actuation is presented. A complete dynamics model is derived using the principles of variational mechanics, relaxing some common assumptions made in prior literature on control moment gyroscopes. These assumptions include perfect axisymmetry of the rotor and gimbal structures, and perfect alignment of the centers of mass of the gimbal and the rotor. The resulting dynamics display complex nonlinear coupling between the internal degrees of freedom associated with the CMG and the spacecraft base body’s rotational degrees of freedom in the absence of these assumptions. This dynamics model is further generalized to include the effects of multiple CMGs placed in the spacecraft bus, and sufficient conditions for non-singular CMG cluster configurations are obtained. General ideas on control of the angular momentum of the spacecraft using changes in the momentum variables of a finite number of CMGs, are provided. A control scheme using a finite number of CMGs in the absence of external torques and when the total angular momentum of the spacecraft is zero, is presented. The dynamics model of the spacecraft with a finite number of CMGs is then simplified under the assumption that the rotor is axisymmetric, in which case it is shown that singularities are avoided. As an example, the case of three CMGs with axisymmetric rotors, placed in a tetrahedron configuration inside the spacecraft, is considered. The control scheme is then numerically implemented using a geometric variational integrator and the results confirm the singularity-free property and high control authority of the ASCMG cluster. Moreover, as rotor misalignments are addressed in the dynamics model, the ASCMG cluster can adapt to them without requiring hardware changes.

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Geometric Mechanics Based Modeling of the Attitude Dynamics and Control of Spacecraft With Variable Speed Control Moment Gyroscopes

Volume 1: Aerial Vehicles; Aerospace Control; Alternative Energy; Automotive Control Systems; Battery Systems; Beams and Flexible Structures; Biologically-Inspired Control and its Applications; Bio-Medical and Bio-Mechanical Systems; Biomedical Robots and Rehab; Bipeds and Locomotion; Control Design Methods for Adv. Powertrain Systems and Components; Control of Adv. Combustion Engines, Building Energy Systems, Mechanical Systems; Control, Monitoring, and Energy Harvesting of Vibratory Systems ◽

10.1115/dscc2013-4033 ◽

2013 ◽

Cited By ~ 2

Author(s):

V. Sasi Prabhakaran ◽

Amit K. Sanyal ◽

Frederick Leve ◽

N. Harris McClamroch

Keyword(s):

Degrees Of Freedom ◽

Variational Principles ◽

Speed Control ◽

Variable Speed ◽

Attitude Dynamics ◽

Dynamics Model ◽

Multiple Control ◽

Control Moment ◽

Control Moment Gyroscopes ◽

Variable Speed Control

The attitude dynamics of a spacecraft with a variable speed control moment gyroscope (VSCMG), in the presence of external torques and internal inputs, is derived using variational principles. A complete dynamics model, that relaxes some of the assumptions made in prior literature on control moment gyroscopes, is obtained. A non-standard VSCMG model, that has an offset between the center of the gimbal axis and the center of the rotor (flywheel) is considered. The dynamics equations show the complex nonlinear coupling between the internal degrees of freedom associated with the VSCMG and the spacecraft base body’s attitude degrees of freedom. Some of this coupling is induced by the non-zero offset between the gimbal axis and the rotor center. This dynamics model is then generalized to include the effects of multiple control moment gyroscopes placed in the base body with non-parallel gimbal axes. It is shown that the dynamical coupling can improve the control authority on the angular momentum of the base body of the spacecraft using changes in the momentum variables of the VSCMG. Numerical simulations confirm the use of these VSCMGs for attitude control for a given de-tumbling maneuver.

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Dynamics and Modal Analysis of Gyroelastic Body With Variable Speed Control Moment Gyroscopes

Journal of Computational and Nonlinear Dynamics ◽

10.1115/1.4033438 ◽

2016 ◽

Vol 11 (4) ◽

Cited By ~ 1

Author(s):

Quan Hu ◽

Yinghong Jia ◽

Haiyan Hu ◽

Shijie Xu ◽

Jingrui Zhang

Keyword(s):

Mathematical Model ◽

Angular Momentum ◽

Speed Control ◽

Volume Element ◽

Flexible Structure ◽

Variable Speed ◽

Control Moment ◽

Control Moment Gyroscopes ◽

Parabolic Structure ◽

Variable Speed Control

Gyroelastic body refers to a flexible structure with a distribution of stored angular momentum (called gyricity). In previous studies, it was assumed that each volume element of the structure possesses an infinitesimal spinning rotor so that the distribution of the gyricity is continuous. However, the momentum devices must be discretely distributed in engineering applications; therefore, this paper studies the gyroelastic body formed by directly mounting a set of variable speed control moment gyroscopes (CMGs) on the flexible structure. The detailed dynamics of the CMGs is incorporated to capture the interactions between the CMGs and the structure. The gyroelastic modes and pseudorigid modes are discussed based on the linearized mathematical model. The examples of a gyroelastic beam and a gyroelastic parabolic structure demonstrate several involved concepts and properties.

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