Vibration Reduction on Bending Moment of Flexible Solar Arrays during Orbital Maneuvers by Input Shaping
Some flexible appendages of spacecraft, such as solar arrays, sometimes can be simply modeled as a cantilever lightly damper beam.Subsequently, a dynamic analysis about the cantilever beam is given.However, the more complicated solar array structure, for example, with an extendable retractable telescopic mast (ERM), which has been successfully applied in the International Space Station (ISS), is also a common kind of solar arrays.Whatever kind of solar array structure, vibration problem which can be reflected by the bending moment on the joint is unavoidable during orbital maneuvers.An effective measure is taken to eliminate the vibration of the bending moment in this paper.In this research, based on the differential equation of motion constructed, the solar array during on-orbit maneuver is considered as a multi-freedom dynamics system.The impulse excitation during the process of the orbit maneuver can be regards as acceleration with the form of rectangular wave imposed on the solar array.A ZV input shaper is designed to convolve with the original acceleration.The shaped acceleration may result in a relative displacement between the spacecraft body and the solar array, which is realized by a linear motor rail.Then, a finite element (FE) model about practical solar arrays with a coilable lattice mast (CM) is built by FE software.A modal analysis is completed to find the first several low frequency fundamental vibration modes that possibly take a more important part in the flexible vibration of the solar arrays.A time transient response result is obtained by FE analysis.The bending moment of the joint is measured instead of the displacement or acceleration at the tip because it’s convenient for measurement and useful for avoiding damage to the structure.The simulation result shows that the flexible vibration of the bending moment is suppressed effectively.So it can be seen that the solar array almost moves at a rigid-body amount with the input shaped.Furthermore, the shaping method is improved through releasing the constraint conditions to decrease the relative sliding.The time response result shows that the improvement is successful.Following that, a cantilever beam model is simulated and the time response of the bending moment on the joint shows that the flexible vibration is reduced effectively.At last, a test about the scaled model is given.The model employed in the test is a steel beam fixed on a slider running on a rail whose friction could be ignored.The results of the simulation and the experiment demonstrate that the flexible vibration of the bending moment of the joint during orbital maneuver can be reduced effectively by the method proposed in this paper.
Zhu Chun-yan Tang Guo-an Guo Qi-wei
Department of Mechanics and Engineering Science Fudan University Shanghai, 200433, China Department of Mechanics and Engineering Science & Shanghai Key Laboratory of Spacecraft Mechanism Fu Shanghai Key Laboratory of Spacecraft Mechanism Aerospace System Engineering Shanghai Shanghai, 2011
国际会议
上海
英文
1-8
2012-08-26（万方平台首次上网日期，不代表论文的发表时间）