Integrated Power and Attitude Control for a Spacecraft with Flywheels and Control Moment Gyroscopes
1
Citation
0
Reference
20
Related Paper
Abstract:
A law is designed for simultaneous control of the orientation of an Earth-pointing spacecraft, the energy stored by counter-rotating flywheels, and the angular momentum of the flywheels and control moment gyroscopes used together as all integrated set of actuators for attitude control. General. nonlinear equations of motion are presented in vector-dyadic form, and used to obtain approximate expressions which are then linearized in preparation for design of control laws that include feedback of flywheel kinetic energy error as it means of compensating for damping exerted by rotor bearings. Two flywheel 'steering laws' are developed such that torque commanded by all attitude control law is achieved while energy is stored or discharged at the required rate. Using the International Space Station as an example, numerical simulations are performed to demonstrate control about a torque equilibrium attitude and illustrate the benefits of kinetic energy error feedback.Keywords:
Flywheel
Control moment gyroscope
Reaction wheel
Cite
To avoid the singularity of control moment gyroscopes,a system consisting of three orthogonally mounted scissor pairs of control moment gyroscopes is employed as an actuator for spacecraft attitude control.An accurate mathematical model of spacecraft attitude motion manipulated by the gyroscope system is derived on the basis of Newton-Euler method.On this basis,a nonlinear control law is designed for the spacecraft to implement large-angle attitude maneuvers.In the design process,the stability of the attitude control system is proved.Singularity analysis of the gyroscope system shows that there exists no inner singularity in this system.A pseudo inverse control law is proposed for keeping the gimbal angles of each scissor pair of gyroscope synchronous.To improve the synchronization performance and the anti-disturbance ability of the system,an adaptive nonlinear feedback controller is designed on the basis of stability theory of Lyapunov.Simulation verifies the validity of the designed control laws and manipulation law,as well as the capability of the gyroscope system in driving the spacecraft to implement large angle attitude maneuver.
Control moment gyroscope
Lyapunov stability
Basis (linear algebra)
Cite
Citations (0)
An integrated power and attitude control system with two variable speed control moment gyroscopes positioned with their spin axes nominally co-aligned on the longitudinal roll axis of spacecraft is discussed. The system facilitates the management of electrical power and the generation of attitude control torque by accelerating or decelerating the flywheels to change the amounts of their angular momentum. Furthermore, the attitude control torque is also generated by providing the gimbal angular velocity with respect to the spacecraft body. The present research provides detailed description of the flywheel configuration and develops the complete equations of motion. A discontinuous time-invariant feedback control law is developed for attitude stabilization of the underactuated system under the restriction of zero total angular momentum. Simultaneous power tracking is completed by using a null space solution. This proposed conception is supposed to provide useful operation over very long-duration flights in light weight and low cost because of eliminating the traditional propulsive system and utilizing less flywheels than previous researches.
Flywheel
Control moment gyroscope
Reaction wheel
Underactuation
Cite
Citations (4)
Control moment gyroscope
Momentum (technical analysis)
Cite
Citations (0)
The attitude-tracking control of a rigid spacecraft using only two internal torques is addressed. First, a given reference trajectory is classified as feasible or unfeasible according to the preservation or violation of the momentum conservation law. The dynamics of the attitude-tracking error is then formulated on the attitude manifold SO(3) with the angular momentum of the actuators as inputs. Given the Lie group structure of SO(3), the transverse function approach is utilized to design an attitude-tracking law ensuring asymptotically ultimately bounded tracking error for any reference trajectory. For feasible reference trajectories satisfying certain persistence conditions, asymptotic tracking is achieved by constructing an asymptotically stable zero dynamics for the closed-loop system. To deliver control torques to the actuator command signals, steering laws are designed for two reaction wheels, two single-gimbal control moment gyros mounted in parallel, and one variable-speed control moment gyro, respectively. The resulting control law can be applied to a spacecraft with different kinds of momentum actuators but underactuated for tasks ranging from bounded tracking of a generic trajectory, three-axis earth pointing to line-of-sight pointing, etc. Numerical examples are presented to verify the effectiveness of the proposed method.
Control moment gyroscope
Tracking error
Underactuation
Reaction wheel
Tracking (education)
Cite
Citations (31)
The attitude dynamics of a spacecraft with a variable speed control moment gyroscope (VSCMG), in the presence of conservative external inputs, are derived in the framework of geometric mechanics. A complete dynamics model, that relaxes some of the assumptions made in prior literature on control moment gyroscopes, is obtained. These dynamics equations show the complex nonlinear coupling between the internal degrees of freedom associated with the CMG and the spacecraft base body's attitude degrees of freedom. General ideas on how this coupling can be used to control the angular momentum of the base body of the spacecraft using changes in the momentum variables of a finite number of VSCMGs, are provided. Placement of VSCMGs in the spacecraft base body is carried out in a manner that avoids singularities in the transformation between VSCMG angular rates and required instantaneous base body angular momentum. A control scheme using n VSCMGs for slew to rest attitude maneuvers in the absence of external torques and when the total angular momentum of the spacecraft is zero, is presented. Numerical simulation results obtained for a spacecraft with three VSCMGs confirm the stability properties of the feedback system.
Control moment gyroscope
Cite
Citations (5)
This paper discusses spacecraft control using variable-speed CMGs. A new operational concept for VSCMGs is proposed. This new concept makes it possible to approximate the complex nonlinear system by a linear time-varying system (LTV). As a result, an effective control system design method, Model Predictive Control (MPC) using robust pole assignment, can be used to design the spacecraft control system using VSCMGs. A nice feature of this design is that the control system does not have any singular point. A design example is provided. The simulation result shows the effectiveness of the proposed method.
Control moment gyroscope
Model Predictive Control
Cite
Citations (19)
The spacecraft with flywheels becomes under-actuated and the attitude controllability goes worse when only two flywheels can work.We deal with this problem for a rigid spacecraft with two flywheels.A new controller is designed by using the Backstepping design method,under the assumption of zero momentum for the spacecraft.The design process is in two steps:First,the desired angular velocity is designed to stabilize the attitude of the spacecraft,by considering the kinematics only.Next,the dynamics is combined to give the attitude control torque.The controller is a discontinuous one. It makes the attitude of the under-actuated spacecraft globally asymptotically converge to zero,and the system has a rapid and desirable transient process.Finally,simulation results indicate the feasibility of the controller presented above.
Flywheel
Reaction wheel
Cite
Citations (0)
We present new results on attitude control of spacecraft with flywheels, where the wheels are also used to store energy as "mechanical batteries" A brief review of the literature of this concept is given. The nonlinear equations of motion for a gyrostat model are given in dimensionless form, and recognized as a noncanonical Hamiltonian system. Decomposition of the space of internal torques separates the attitude control function from the energy storage function. A class of control laws is developed to execute large-angle rotational maneuvers while simultaneously performing energy storage and extraction operations.
Flywheel
Flywheel energy storage
Dimensionless quantity
Rotational energy
Mechanical energy
Hamiltonian (control theory)
Cite
Citations (52)
The control law of the flywheel in an integrated power and attitude control system (IPACS) for a spacecraft is investigated. The flywheels are used as attitude control actuators as well as energy storage device. A feedback control law for attitude tracking is firstly developed by using Lyapunov approach, and then a torque based control law of the flywheel is studied. The control torque vector of the flywheel is decomposed into three parts which are orthogonal to one another by using the method of singularity value decomposition (SVD). One part is used to provide the attitude control torque, another part is used to store energy with given power, and the last part is used to accomplish wheel speed equalization to avoid wheel saturation caused by large difference among the wheel spin rates. A management scheme for energy storage power using kinetic energy feedback is proposed to keep energy balance, which can avoid wheel saturation caused by superfluous energy. Numerical simulation results demonstrate the effectiveness of the control scheme
Flywheel
Flywheel energy storage
Reaction wheel
Cite
Citations (11)
Several laws are designed for simultaneous control of the orientation of an Earth-pointing spacecraft, the energy stored by counter-rotating flywheels, and the angular momentum of the flywheels and control moment gyroscopes used together as an integrated set of actuators for attitude control. General, nonlinear equations of motion are presented in vector-dyadic form, and used to obtain approximate expressions which are then linearized in preparation for design of control laws that include feedback of flywheel kinetic energy error as a means of compensating for damping exerted by rotor bearings. Two flywheel steering laws are developed such that torque commanded by an attitude control law is achieved while energy is stored or discharged at the required rate. Using the International Space Station as an example, numerical simulations are performed to demonstrate control about a torque equilibrium attitude, and illustrate the benefits of kinetic energy error feedback. Control laws for attitude hold are also developed, and used to show the amount of propellant that can be saved when flywheels assist the CMGs. Nonlinear control laws for large-angle slew maneuvers perform well, but excessive momentum is required to reorient a vehicle like the International Space Station.
Flywheel
Control moment gyroscope
Reaction wheel
Cite
Citations (9)