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Статті в журналах з теми "Flexible gimbal"

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Автор: Grafiati

Опубліковано: 30 травня 2022

Оновлено: 31 травня 2022

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Qi, Yuan, Hui Lin Wang, Qing Qing Xu, Yan Lu Du, Xin Zheng Shao, and Hong Yang. "A new flexible gimbal for electro-optical sighting system (EOSS)." Optik 242 (September 2021): 167016. http://dx.doi.org/10.1016/j.ijleo.2021.167016.

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Muraoka, Y., H. Ryoson, T. Kawashima, M. Kondo, Y. Kaneta, and Y. Okazaki. "Vibration analysis of a contact slider/gimbal of a flexible disk drive." Microsystem Technologies 9, no. 1-2 (November 1, 2002): 41–47. http://dx.doi.org/10.1007/s00542-001-0152-8.

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Jia, Shiyuan, and Jinjun Shan. "Flexible Structure Vibration Control Using Double-Gimbal Variable-Speed Control Moment Gyros." Journal of Guidance, Control, and Dynamics 44, no. 5 (May 2021): 954–66. http://dx.doi.org/10.2514/1.g005684.

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Qi, Y., M. Ji, H. L. Wang, Q. Q. Xu, and G. Wang. "A two-stage stabilizing device of multi-degree gimbal based on flexible structure." Journal of Physics: Conference Series 1507 (March 2020): 092007. http://dx.doi.org/10.1088/1742-6596/1507/9/092007.

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Ryoson, H., M. Kondo, K. Goto, T. Kawashima, S. Nagata, Y. Muraoka, Y. Matsui, Y. Kaneta, and Y. Okazaki. "A novel contact slider/gimbal to raise recording density in flexible disk drives." Microsystem Technologies 8, no. 2-3 (May 1, 2002): 188–93. http://dx.doi.org/10.1007/s00542-001-0145-7.

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Wei, Changzhu, Ruiming Wang, Wei Zheng, and Jialun Pu. "Equivalent dynamic modeling of flexible morphing aircraft." Science Progress 104, no. 2 (April 2021): 003685042110109. http://dx.doi.org/10.1177/00368504211010946.

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A morphing aircraft can maintain optimal flight performance by adaptively changing shape. However, large deformation and fast motion of aircraft modules lead to complicated dynamics during morphing process. This paper proposes a mechanistic equivalent model with parameters identified by optimization method. Based on the dynamics of the aircraft modules with large deformation and fast motion and considering the coupling characteristics of rigid bodies and gimbal joints, an equivalent dynamic model of morphing aircraft is built in this study. Considering the huge amount of highly coupled parameters in the equivalent model, particle swarm optimization algorithm is used to identify the equivalent parameters based on the sample data of flexible model. By comparing the simulation results of proposed model to those of rigid model and flexible model, it can be seen that the accuracy of the proposed equivalent model is comparable to that of the flexible model, but the computational load is only 10% of that of flexible model. Further, based on this high-fidelity model with low computational load, an optimized morphing process is obtained, and the attitude variation during morphing is reduced by 4.23%.

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Sun, Jianjun, Yalin Ding, Hongwen Zhang, Guoqin Yuan, and Yuquan Zheng. "Conceptual Design and Image Motion Compensation Rate Analysis of Two-Axis Fast Steering Mirror for Dynamic Scan and Stare Imaging System." Sensors 21, no. 19 (September 27, 2021): 6441. http://dx.doi.org/10.3390/s21196441.

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In order to enable the aerial photoelectric equipment to realize wide-area reconnaissance and target surveillance at the same time, a dual-band dynamic scan and stare imaging system is proposed in this paper. The imaging system performs scanning and pointing through a two-axis gimbal, compensating the image motion caused by the aircraft and gimbal angular velocity and the aircraft liner velocity using two two-axis fast steering mirrors (FSMs). The composition and working principle of the dynamic scan and stare imaging system, the detailed scheme of the two-axis FSM and the image motion compensation (IMC) algorithm are introduced. Both the structure and the mirror of the FSM adopt aluminum alloys, and the flexible support structure is designed based on four cross-axis flexural hinges. The Root-Mean-Square (RMS) error of the mirror reaches 15.8 nm and the total weight of the FSM assembly is 510 g. The IMC rate equations of the two-axis FSM are established based on the coordinate transformation method. The effectiveness of the FSM and IMC algorithm is verified by the dynamic imaging test in the laboratory and flight test.

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Li, Xiongfei, and Wei Cheng. "Research on Microvibrations Generated by a Control Moment Gyroscope on a Flexible Interface Based on a Dynamic Substructure Method." International Journal of Aerospace Engineering 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/5045740.

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Microvibrations generated by a control moment gyroscope (CMG) will couple with a flexible spacecraft structure, and this seriously degrades certain point performances of a spacecraft. This study focuses on investigating the coupled microvibrations caused by a CMG on a flexible interface by using a dynamic substructure method (DSM). First, a DSM based on a frequency response function (FRF) is established, and this method is used to simultaneously synthesize multiple substructures with different coordinates irrespective of whether their connection interfaces are rigid or flexible. Second, the bearings and the gimbal servo system are simplified into linear springs, and therefore the CMG model is equivalent to a mass-spring-damping system with eighteen degrees of freedom (DOFs). Third, the established DSM is employed to deduce the FRF matrix of the CMG-flexible interface coupling system that consists of CMG mounted on an aluminum honeycomb sandwich palate (AHSP). Dynamic responses of the coupling system are calculated by the derived FRF matrix. Finally, MATLAB and multibody dynamics simulations are conducted to analyze and validate the dynamic responses of the coupling system obtained by the DSM. The results indicate that the DSM is appropriate to predict the coupled microvibrations of CMG on a flexible interface and exhibits high prediction accuracy and computational efficiency.

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Ruiz, O. J., and D. B. Bogy. "A Numerical Simulation of the Head-Disk Assembly in Magnetic Hard Disk Files: Part I—Component Models." Journal of Tribology 112, no. 4 (October 1, 1990): 593–602. http://dx.doi.org/10.1115/1.2920303.

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In previous papers the dynamics of air bearing sliders used to carry the read/write transducers in magnetic hard disk files has been studied. These studies are useful in evaluating the steady flying and stability of sliders subjected to various disturbances. They are particularly useful in finding the natural frequencies of the air bearings. However, in hard disk drives the sliders are attached to suspensions, which are highly specialized structures that connect the sliders to the positioning actuators. These suspensions have to be relatively stiff in lateral translation, but very flexible in pitch and roll. This latter feature is accomplished by the gimbal or flexure that connects the slider to the end of the suspension. The suspension-gimbal structure has its own natural frequencies, which can be excited by disturbances such as track seeking and impacting the actuator against the crash stop. In order to study the effect of these structures on the head-disk spacing it is necessary to include them in the numerical simulator. In this two part study such a simulator is developed. In Part I the component parts and their interfaces are modeled. In Part II the numerical simulation of the coupled system is accomplished and the numerical results of several sample simulations are presented and discussed.

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White, James. "Slider Air Bearing Design Enhancements for High Speed Flexible Disk Recording." Journal of Tribology 127, no. 3 (June 13, 2005): 522–29. http://dx.doi.org/10.1115/1.1843151.

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The current effort was motivated largely by the fact that computing and communication platforms are becoming more portable and mobile with increased demands for both speed and disk storage. This work makes use of an asymmetric opposed slider arrangement to provide both static and dynamic improvements to the recording head air bearing interface for high speed flexible disk applications. The combination of a longitudinally slotted rail opposed by an uninterrupted rail that functions as a noncontact hydrodynamic pressure pad causes the disk to deflect at the submicron level over critical areas of the slider interface. This allows the required static minimum flying height to be focused over the recording transducer while higher clearances are positioned elsewhere, resulting in minimized exposure to contact between slider and disk. The high stiffness and low flying height of the air film at the recording element together with the low stiffness and high flying height of the opposing air film provides a noncontact air bearing interface that is especially immune to mechanical shock. A computer code called FLEXTRAN was developed that provides both static and dynamic numerical solutions of the air bearing interface composed of two opposed gimbal mounted sliders loaded against a high speed flexible disk. Simulations of the asymmetric opposed slider configuration are presented and compared with those of other slider air bearing designs.

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Zhang, Shuhang, Chun Liu, and Yuan Zhou. "UAV-Based Gigapixel Panoramic Image Acquisition Planning with Ray Casting-Based Overlap Constraints." Journal of Sensors 2019 (May 2, 2019): 1–9. http://dx.doi.org/10.1155/2019/4845104.

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Panoramic imaging is information-rich, low-cost, and effective. In panoramic image acquisition, unmanned aerial vehicles (UAVs) have a natural advantage that owes to their flexibility and relatively large observation ranges. Using a panoramic gimbal and a single camera may be the most common means of capturing gigapixel panoramas. In order to manage the constraints of UAV power and facilitate the use of a variety of camera lenses, an effective and flexible method for planning UAV gigapixel panorama acquisitions is required. To address this need, a panoramic image acquisition planning method is proposed in this paper. The method defines image overlaps via a ray casting procedure and then generates an acquisition plan according to the constraints of horizontal and vertical overlap thresholds. This method ensures the completeness of the panorama by maintaining the overlap between adjacent images. Two experiments, including simulated and field cases, were performed to evaluate the proposed method through comparisons with an existing panorama acquisition plan. Results showed that the proposed method can capture complete panoramas with fewer images.

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Baek, Joo Hyun. "Modeling on an Antenna Flexible Characteristics of a Prototype Gimbal with an Antenna and Major Design Factors to determine a System Bandwidth." Transactions of the Korean Society of Mechanical Engineers A 29, no. 5 (May 1, 2005): 743–53. http://dx.doi.org/10.3795/ksme-a.2005.29.5.743.

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Ungermann, J., M. Kaufmann, L. Hoffmann, P. Preusse, H. Oelhaf, F. Friedl-Vallon, and M. Riese. "Towards a 3-D tomographic retrieval for the air-borne limb-imager GLORIA." Atmospheric Measurement Techniques 3, no. 6 (November 29, 2010): 1647–65. http://dx.doi.org/10.5194/amt-3-1647-2010.

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Abstract. GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) is a new remote sensing instrument essentially combining a Fourier transform infrared spectrometer with a two-dimensional (2-D) detector array in combination with a highly flexible gimbal mount. It will be housed in the belly pod of the German research aircraft HALO (High Altitude and Long Range Research Aircraft). It is unique in its combination of high spatial and state-of-the art spectral resolution. Furthermore, the horizontal view angle with respect to the aircraft flight direction can be varied from 45° to 135°. This allows for tomographic measurements of mesoscale events for a wide variety of atmospheric constituents. In this paper, a tomographic retrieval scheme is presented, which is able to fully exploit the manifold radiance observations of the GLORIA limb sounder. The algorithm is optimized for massive 3-D retrievals of several hundred thousands of measurements and atmospheric constituents on common hardware. The new scheme is used to explore the capabilities of GLORIA to sound the atmosphere in full 3-D with respect to the choice of the flightpath and to different measurement modes of the instrument using ozone as a test species. It is demonstrated that the achievable resolution should approach 200 m vertically and 20 km–30 km horizontally. Finally, a comparison of the 3-D inversion with conventional 1-D inversions using the assumption of a horizontally homogeneous atmosphere is performed.

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Ungermann, J., M. Kaufmann, L. Hoffmann, P. Preusse, H. Oelhaf, F. Friedl-Vallon, and M. Riese. "Towards a 3-D tomographic retrieval for the Air-borne Limb-imager GLORIA." Atmospheric Measurement Techniques Discussions 3, no. 4 (July 15, 2010): 2995–3046. http://dx.doi.org/10.5194/amtd-3-2995-2010.

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Abstract. GLORIA (Gimballed Limb Observer for Radiance Imaging of the Atmosphere) is a new remote sensing instrument essentially combining a Fourier transform infrared spectrometer with two two-dimensional (2-D) detector arrays in combination with a highly flexible gimbal mount. It will be housed in the belly pod of the German research aircraft HALO (High Altitude and Long Range Research Aircraft). It is unique in its high spatial and spectral resolution. Furthermore, the horizontal view angle with respect to the aircraft can be varied from 45° to 135°. This allows for tomographic measurements of mesoscale events for a wide variety of atmospheric constituents. In this paper, a fast tomographic retrieval scheme is presented, which is able to fully exploit the high-resolution radiance observations of the GLORIA limb sounder. The algorithm is optimized for massive 3-D retrievals of several hundred thousands of measurements and atmospheric constituents on common hardware. The new scheme is used to explore the capabilities of GLORIA to sound the atmosphere in full 3-D with respect to the choice of the flightpath and to different measurement modes of the instrument using ozone as a test species. It is demonstrated that the achievable resolution should approach 200 m vertically and 20 km–30 km horizontally. Finally, a comparison of the 3-D inversion with conventional 1-D inversions using the assumption of a horizontally homogeneous atmosphere is performed.

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Kargo, William J., Frank Nelson, and Lawrence C. Rome. "Jumping in frogs: assessing the design of the skeletal system by anatomically realistic modeling and forward dynamic simulation." Journal of Experimental Biology 205, no. 12 (June 15, 2002): 1683–702. http://dx.doi.org/10.1242/jeb.205.12.1683.

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SUMMARY Comparative musculoskeletal modeling represents a tool to understand better how motor system parameters are fine-tuned for specific behaviors. Frog jumping is a behavior in which the physical properties of the body and musculotendon actuators may have evolved specifically to extend the limits of performance. Little is known about how the joints of the frog contribute to and limit jumping performance. To address these issues, we developed a skeletal model of the frog Rana pipiens that contained realistic bones, joints and body-segment properties. We performed forward dynamic simulations of jumping to determine the minimal number of joint degrees of freedom required to produce maximal-distance jumps and to produce jumps of varied take-off angles. The forward dynamics of the models was driven with joint torque patterns determined from inverse dynamic analysis of jumping in experimental frogs. When the joints were constrained to rotate in the extension—flexion plane, the simulations produced short jumps with a fixed angle of take-off. We found that, to produce maximal-distance jumping,the skeletal system of the frog must minimally include a gimbal joint at the hip (three rotational degrees of freedom), a universal Hooke's joint at the knee (two rotational degrees of freedom) and pin joints at the ankle,tarsometatarsal, metatarsophalangeal and iliosacral joints (one rotational degree of freedom). One of the knee degrees of freedom represented a unique kinematic mechanism (internal rotation about the long axis of the tibiofibula)and played a crucial role in bringing the feet under the body so that maximal jump distances could be attained. Finally, the out-of-plane degrees of freedom were found to be essential to enable the frog to alter the angle of take-off and thereby permit flexible neuromotor control. The results of this study form a foundation upon which additional model subsystems (e.g. musculotendon and neural) can be added to test the integrative action of the neuromusculoskeletal system during frog jumping.

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Ford, Kevin A., and Christopher D. Hall. "Flexible Spacecraft Reorientations Using Gimbaled Momentum Wheels." Journal of the Astronautical Sciences 49, no. 3 (September 2001): 421–41. http://dx.doi.org/10.1007/bf03546231.

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Muise, Aaron, and Robert J. Bauer. "A COMPARISON OF THE EFFECTIVENESS OF DOUBLE- AND SINGLE-GIMBALED CONTROL MOMENT GYROSCOPES FOR VIBRATION SUPPRESSION." Transactions of the Canadian Society for Mechanical Engineering 29, no. 3 (September 2005): 389–402. http://dx.doi.org/10.1139/tcsme-2005-0024.

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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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Quadrelli, Bruno Marco, and Andreas H. von Flotow. "Pointing dynamics of gimbaled payloads on flexible spacecraft." Journal of Guidance, Control, and Dynamics 17, no. 6 (November 1994): 1387–89. http://dx.doi.org/10.2514/3.21367.

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Liu, Jiafu, Siyuan Rong, Fan Shen, and Naigang Cui. "Dynamics and Control of a Flexible Solar Sail." Mathematical Problems in Engineering 2014 (2014): 1–25. http://dx.doi.org/10.1155/2014/868419.

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Solar sail can merely make use of solar radiation pressure (SRP) force as the thrust for space missions. The attitude dynamics is obtained for the highly flexible solar sail with control vanes, sliding masses, and a gimbaled control boom. The vibration equations are derived considering the geometric nonlinearity of the sail structure subjected to the forces generated by the control vanes, solar radiation pressure (SRP), and sliding masses. Then the dynamic models for attitude/vibration controller design and dynamic simulation are obtained, respectively. The linear quadratic regulator (LQR) based and optimal proportional-integral (PI) based controllers are designed for the coupled attitude/vibration models with constant disturbance torques caused by the center-of-mass (cm)/center-of-pressure (cp) offset, respectively. It can be concluded from the theoretical analysis and simulation results that the optimal PI based controller performs better than the LQR based controller from the view of eliminating the steady-state errors. The responses with and without the geometrical nonlinearity are performed, and the differences are observed and analyzed. And some suggestions are also presented.

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Crawford, J. Douglas, Melike Z. Ceylan, Eliana M. Klier, and Daniel Guitton. "Three-Dimensional Eye-Head Coordination During Gaze Saccades in the Primate." Journal of Neurophysiology 81, no. 4 (April 1, 1999): 1760–82. http://dx.doi.org/10.1152/jn.1999.81.4.1760.

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Three-dimensional eye-head coordination during gaze saccades in the primate. The purpose of this investigation was to describe the neural constraints on three-dimensional (3-D) orientations of the eye in space (Es), head in space (Hs), and eye in head (Eh) during visual fixations in the monkey and the control strategies used to implement these constraints during head-free gaze saccades. Dual scleral search coil signals were used to compute 3-D orientation quaternions, two-dimensional (2-D) direction vectors, and 3-D angular velocity vectors for both the eye and head in three monkeys during the following visual tasks: radial to/from center, repetitive horizontal, nonrepetitive oblique, random (wide 2-D range), and random with pin-hole goggles. Although 2-D gaze direction (of Es) was controlled more tightly than the contributing 2-D Hs and Eh components, the torsional standard deviation of Es was greater (mean 3.55°) than Hs (3.10°), which in turn was greater than Eh (1.87°) during random fixations. Thus the 3-D Es range appeared to be the byproduct of Hs and Eh constraints, resulting in a pseudoplanar Es range that was twisted (in orthogonal coordinates) like the zero torsion range of Fick coordinates. The Hs fixation range was similarly Fick-like, whereas the Eh fixation range was quasiplanar. The latter Eh range was maintained through exquisite saccade/slow phase coordination, i.e., during each head movement, multiple anticipatory saccades drove the eye torsionally out of the planar range such that subsequent slow phases drove the eye back toward the fixation range. The Fick-like Hs constraint was maintained by the following strategies: first, during purely vertical/horizontal movements, the head rotated about constantly oriented axes that closely resembled physical Fick gimbals, i.e., about head-fixed horizontal axes and space-fixed vertical axes, respectively (although in 1 animal, the latter constraint was relaxed during repetitive horizontal movements, allowing for trajectory optimization). However, during large oblique movements, head orientation made transient but dramatic departures from the zero-torsion Fick surface, taking the shortest path between two torsionally eccentric fixation points on the surface. Moreover, in the pin-hole goggle task, the head-orientation range flattened significantly, suggesting a task-dependent default strategy similar to Listing’s law. These and previous observations suggest two quasi-independent brain stem circuits: an oculomotor 2-D to 3-D transformation that coordinates anticipatory saccades with slow phases to uphold Listing’s law, and a flexible “Fick operator” that selects head motor error; both nested within a dynamic gaze feedback loop.

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Chen, Xiaocen, Yuan Ren, Yuanwen Cai, Nan Li, and Haipeng Jia. "Integrated control of attitude maneuver and vibration suppression of flexible spacecraft based on magnetically suspended control moment gyros." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science, July 22, 2020, 095440622094280. http://dx.doi.org/10.1177/0954406220942801.

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This paper adopts magnetically suspended control moment gyro (MSCMG) to realize the integration of attitude control and wideband micro-vibration suppression of spacecraft without adding extra hardware resources. The coupling between central rigid body and flexible attachment has been effectively retained in the controller design. First, an open-loop modal observer is constructed in advantage of the inherent physical characteristics of flexible modes, and then an adaptive backstepping controller involving flexible modal estimation, spacecraft attitude quaternion, and angular velocity is designed. Next, the band-pass filters are employed to separate the low-frequency gimbal command angular rate signal and medium–high-frequency rotor command angular rate signal, respectively, so that MSCMG can accurately track the command signal output by the integrated controller. Taking advantage of MSCMG’s ability to output high bandwidth micro-gimbal moment, the proposed method can not only meet the requirement of spacecraft rapid maneuver but also effectively suppress the broadband micro-vibration, including low-frequency flexible vibration and medium–high-frequency micro-vibration caused by spacecraft rotating parts. Numerical simulations and frequency domain analysis demonstrate the correctness and effectiveness of the proposed method.

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Cui, Yangyang, Yongjian Yang, Yukai Zhu, Jianzhong Qiao, and Lei Guo. "Composite Velocity-Tracking Control for Flexible Gimbal System With Multi-Frequency-Band Disturbances." IEEE Transactions on Circuits and Systems I: Regular Papers, 2021, 1–11. http://dx.doi.org/10.1109/tcsi.2021.3095527.

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Fan, Jixiang, and Di Zhou. "Nonlinear Attitude Control of Flexible Spacecraft With Scissored Pairs of Control Moment Gyros." Journal of Dynamic Systems, Measurement, and Control 134, no. 5 (June 5, 2012). http://dx.doi.org/10.1115/1.4006368.

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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.

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Sinclair, Andrew J., and George T. Flowers. "Coupled Flight-Dynamic and Low-Order Aeroelastic Model for a Slender Launch Vehicle." Journal of Vibration and Acoustics 135, no. 2 (February 25, 2013). http://dx.doi.org/10.1115/1.4023049.

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This paper presents a method to develop a low-order aeroelastic model that qualitatively captures some of the phenomena experienced by launch vehicles, suitable for use in preliminary controller design. Equations of motion for the two-dimensional dynamics are derived by treating the vehicle as a beam with a gimbaled nozzle attached at the aft end. The flexible-body dynamics are kinematically described using a modal representation. An aerodynamic model focuses on flow separations at diameter transitions in the transonic regime that can lead to lengthwise variations in the applied aerodynamic force. Additionally, convective effects are modeled that lead to time lag in the aerodynamic forces. The equations of motion are tenth order when neglecting convective effects and twelfth order when including convective effects. The model demonstrates some of the possible coupling that occurs between rigid-body, flexible-body, and aerodynamic states. For representative parameter values, the aeroelastic coupling can destabilize the flexible-body motion. The resulting linearized model is not fully controllable, however, is stabilizable.

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Park, Junyoung, and Alan Palazzolo. "Magnetically Suspended VSCMGs for Simultaneous Attitude Control and Power Transfer IPAC Service." Journal of Dynamic Systems, Measurement, and Control 132, no. 5 (August 11, 2010). http://dx.doi.org/10.1115/1.4002105.

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This paper presents the theory and numerical results of utilizing four gimbaled, magnetically suspended, variable speed flywheels for simultaneous satellite attitude control and power transfer (charge, storage, and delivery). Previous variable speed control moment gyro models and control algorithms assumed that the flywheel bearings were rigid. However, high speed flywheels on spacecraft will be supported by active magnetic bearings, which have flexibility and in general frequency dependent characteristics. The present work provides the theory for modeling the satellite and flywheel systems including controllers for stable magnetic bearing suspension for power transfer to and from the flywheels and for attitude control of the satellite. A major reason for utilizing flexible bearings is to isolate the imbalance disturbance forces from the flywheel to the satellite. This g-jitter vibration could interfere with the operation of sensitive onboard instrumentation. A special control approach is employed for the magnetic bearings to reject the imbalance disturbances. The stability, robustness, tracking, and disturbance rejection performances of the feedback control laws are demonstrated with a satellite simulation that includes initial attitude error, system modeling error, and flywheel imbalance disturbance.

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