Vibration Of Solar Panel Research Articles

Semi-active vibration control of a rotating flexible plate using stiffness and damping actively tunable joint

Lighter structures are increasingly required for flexible spacecraft. However, low frequency and large amplitude vibration problems are unavoidable due to external disturbances or attitude maneuvering especially when working under a microgravity environment. Therefore, a new methodology involving a semi-active technique using an actively tunable joint with variable stiffness and damping control, capable of handling such issues is proposed in this study. The incentive active joint was conceived with a compact structure, based on the electromagnetic direct drive principle. First, a dynamic model of rotating flexible plate was established. Then, a prototype was fabricated and tested. Finally, on the one hand, numerical simulations and experimental results indicated that, when the joint torsional stiffness changed, a frequency shift phenomenon occurred. On the other hand, two types of noncontact periodic vibration excitation methods along the rotation direction were proposed and the experimental results validated that the major frequency bandwidth of interference signal was 0.08–0.52 Hz with a significant vibration attenuation of 5.5–31.5 dB in effective bandwidth. Moreover, in the low frequency range (0.08–0.43 Hz), variable damping was found to be the main factor and variable stiffness was the secondary factor. However, in the high frequency range (around 0.52 Hz), variable stiffness was dominant and variable damping was inferior. These findings are expected to effectively suppress the low frequency and large amplitude vibration of solar panels with flexible joints.

Active Vibration Control of Flexible Satellites Using Solid Propellant Microthruster Array

AbstractThe paper studies a method which uses a solid propellant microthruster array (SPMA) as an actuator to control vibration of solar panels and the attitude of a satellite simultaneously. To so...

Dynamics modeling and attitude control of a flexible space system with active stabilizers

Attitude control of rigid-flexible multi-body systems by active stabilizers is studied in this paper. During slewing maneuvers, flexible members like solar panels may be excited to vibrate. These vibrations, in turn, produce oscillatory disturbing forces on other subsystems and consequently produce error in the spacecraft motion. Also, to develop a proper model-based controller for such complicated system, the system dynamic model is derived. However, due to practical limitations and real-time control implementation, the system dynamic model should be structured such that low computations burden will be imposed on the model-based controller. In this paper, in contrast to many accumulating dynamic modeling approach, a precise compact dynamic model for an active stabilized spacecraft (ASS) system with flexible members is derived. Toward this goal, the total system is virtually partitioned into two rigid and flexible portions. Moreover, the obtained model of these complicated systems is vigorously verified using ANSYS and ADAMS programs. Finally, based on the derived dynamics and a proper virtual damping parameter, an attitude control algorithm is then developed. The suggested controller structure takes the advantage of utilizing the piezoelectric smart materials to dissipate the vibration of solar panels. The obtained results reveal the merits and effectiveness of the proposed suggested modeling and control methods for reliable attitude maneuvering of the system. In addition, it will be shown that the undesired vibrations of the flexible solar panels result in disturbing forces on the ASS system which can be significantly eliminated by the proposed attitude control algorithm.

Accurate and Stable Control of Shenzhou Spacecraft in Rendezvous and Docking

Rendezvous and docking is a key operational technology for human beings to explore and use space. In November 2011 and June 2012, China achieved successful automatic and manual rendezvous and docking between Shenzhou-8, Shenzhou-9 and Tiangong-1, respectively. The control difficulty of these rendezvous and docking lies in flexible vibration of solar panels, cross-coupling between attitude and position control, and serious disturbances caused by thrusters’ plume. To solve these problems, an intelligent adaptive control method is proposed based on a characteristic model based intelligent adaptive control theory. Combined with a proper thruster control allocation algorithm, the on-orbit application of this control method has gained a complete success. This paper will concentrate on the basic principle, design method, theoretical analysis and on-orbit application of this intelligent adaptive control method. And the application of this method in future rendezvous and docking tasks and other spacecraft control projects will be discussed.