• International Journal of Aeronautical and Space Sciences
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• v.3 no.2
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• pp.1-12
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• 2002

This paper considers the robust and optimal three-axis attitude stabilization of rigid spacecraft with inertia uncertainties. The attitude motion of rigid spacecraft described in terms of either the Cayley-Rodrigues parameters or the Modified Rodrigues parameters is considered. A class of robust nonlinear control laws with relaxed feedback gain structures is proposed for attitude stabilization of rigid spacecraft with inertia uncertainties. Global asymptotic stability of the proposed control laws is shown by using the LaSalle Invariance Principle. The optimality properties of the proposed control laws are also investigated by using the Hamilton-Jacobi theory. A numerical example is given to illustrate the theoretical results presented in this paper.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.92.2-92
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• 2001

This paper presents the time optimal reorientation solution of three-axis spacecraft which has only three magnetic torquers. It has been very difficult problem because the magnetic torquer generates only perpendicular to Earth magnetic field vector. In this paper, minimum-time solution using only magnetic torquer is solved using collocation method and nonlinear programming solver NPSOL. IGRF Earth magnetic field model used to simulate magnetic field. The result is verified by comparing to the result of numerical integration. The solution is obtained for the various reorientation maneuver of three axes rigid spacecraft. And the results show that all three axes of rigid spacecraft are controlled effectively only by magnetic torqure.

• International Journal of Aeronautical and Space Sciences
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• v.7 no.1
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• pp.65-72
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• 2006

A variable structure controller with an optimized sliding surface is proposed for slew maneuver of a rigid spacecraft. Rodrigues parameters are chosen to represent the spacecraft attitude. The quadratic type of performance index is used to design the sling surface. For optimization of the sliding surface, a Hamilton- Jacobi-Bellman equation is formulated and it is solved through the numerical algorithm using Galerkin approximation. The solution denotes a nonlinear sliding surface, on which the trajectory of the system satisfies the optimality condition approximately. Simulation result demonstrates that the proposed controller is effectively applied to the slew maneuver of a rigid spacecraft.

• Coupled systems mechanics
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• v.8 no.1
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• pp.19-38
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• 2019

The influence of torsional rigidity of hinged flexible appendage on the linear dynamics of flexible spacecrafts with liquid on board was analyzed by considering the spacecraft's main body as a rigid tank, its flexible appendages as two elastically supported elastic beams, and the onboard liquid as an ideal liquid. The meniscus of the liquid free surface due to surface tension was considered. Using the Lagrangian of the spacecraft's main body (rigid tank), onboard liquid, and two beams (flexible appendages) in addition to assuming the system moved symmetrically, the coupled system frequency equations were obtained by applying the Rayleigh-Ritz method. The influence of the torsional rigidity of the flexible appendages on the spacecraft's coupled vibration characteristics was primary focus of investigation. It was found that coupled vibration modes especially that of appendage considerably changed with torsion spring parameter ${\kappa}_t$ of the flexible appendage. In addition, variation of the main body displacement with system parameters was investigated.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.213-217
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• 1994

The attitude stability of a satellite in spin-stabilized injection mode which contains a liquid pool is investigated. The satellite model for investigation is a two-body system consisting of a the main body, which is symmetric and rigid, representing the spacecraft, and a spherical pendulum, representing the liquid pool. Assuming that both spacecraft and pendulum are in states of steady spin about the symmetry axis of the spacecraft, the coupled nonlinear equations of motion for the system are simplified. In this paper, by using the multiple scales method, the possible resonance conditions in terms of the system parameters are determined and the corresponding near-resonant solutions are derived.

• 제어로봇시스템학회:학술대회논문집
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• 2002.10a
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• pp.68.6-68
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• 2002

$\textbullet$ We solved the attitude regulation and tracking problems of spacecrafts. $\textbullet$ We developed a PC-based 3D spacecraft simulator using OpenGL. $\textbullet$ We considered the rigid spacecrafts with gas-jet and reaction wheel actuator. $\textbullet$ In order to verify the effectiveness of the simulator, we applied the output-based controller $\textbullet$ Spacecraft models are animated by roll-pitch-yaw angles, constantly processed by numerical method.

• International Journal of Aeronautical and Space Sciences
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• v.3 no.2
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• pp.13-23
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• 2002

In this paper, we present a sliding mode control strategy for the re-orientation maneuver of rigid spacecraft containing rotating wheels. The wheels are considered as internal devices, and external inputs are employed for generation of control commands. The formulation is developed for a general case while particular example is applied to pitch bias momentum spacecraft with a single momentum wheel. The resultant control commands are used to take the gyroscopic effects into account which are caused by the rotating wheels. The controller designed demonstrates that the nutational motion of the pitch bias momentum spacecraft is effectively controlled. It is also assumed that the external control torque device is of on-off nature, and pulse width modulation technique is applied to construct proper control torque history.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.1
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• pp.99-107
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• 2017

In this work, the nutation control of rigid spacecraft with only two momentum wheels is addressed by applying the feedback linearization technique. In this strategy, the primary performance index is to regulate the nutational angle by the momentum control of wheels. The spacecraft attitude equations of motion are transformed to a general linearized form by feedback linearization technique, including a guaranteed control law promising the internal dynamics stability to accomplish the nutation angle small. It is proven that the configuration of inertia properties plays a key role in analyzing spacecraft energy level. The behavior of the momentum wheels is also studied analytically and numerically. Finally, the effectiveness of the proposed nonlinear control law for the momentum transfer is verified by conducting numerical simulations.

• Journal of Mechanical Science and Technology
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• v.15 no.2
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• pp.143-151
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• 2001

In the paper, a robust control mechanism is presented to maneuver a flexible spacecraft with the deflection reduction during large slewing operation at the same time. For deflection reduction and maneuvering of the flexible spacecraft, a control mechanism is developed with the application of stochastic optimal sliding-mode control, a linear tracking model and input shaping technique. A start-coast-stop maneuver is employed as a slewing strategy. It is shown that the control mechanism with he strategic maneuver results in better performance and is more efficient than rigid-body-like maneuver, by applying to the Spacecraft Control Laboratory Experiment (SCOLE) system in a space environment.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1330-1333
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• 1997

In this paper, the optimal torque shaping is obtained for 3-axis rotation of a spacecraft. The true optimal 3-axis rotation of rigid spaeraft is first investigated via parameter optimization method with prescribed switching times. Input torque shape of the troque generating device mounted on the central hub is optimized using fourier Series expansion so that the spacecraft may slew while minimizing the vibration energy of flexible modes. Numerical results show that proposed method suggests a reference trahectory for open-loop control, and also verify that it can minimize the vibratory modes of the spacecraft during/after the rest-to-rest maneuver.