Modeling of spacecraft with flexible solar panel considering thermally induced motion
Thermally induced motion of flexible solar panel have significant impact on attitude dynamics and control when the spacecraft experience eclipse transitions. Based on angular momentum theorem thermally induced attitude dynamics of rigid hub with a flexible solar panel is developed. The principle of thermally induced vibration is explained. Thermally induced disturbance toque which initiates attitude error of control system is obtained. Flexible modal response is analyzed with different position of solar panel when satellite enter or exit eclipse. Numerical simulations illustrate that thermally induced disturbance toque mainly distort yaw and roll axis attitude of spacecraft.
Active Vibration Control of Composite Spacecraft Booms Exposed to Solar Radiant Heating
The bending-bending feedback control of vibration and instability of spacecraft booms modeled as circular thin-walled cross-section beams and subjected to solar radiant heating is investigated. Having in view that composite material systems are likely to ply a great role in the design of these devices, the beam constituent materials encompass non-classical effects such as anisotropy and transverse shear. In addition, in order to induce beneficial elastic couplings, a special ply-angle distribution achieved via the usual helically wounding fiberreinforced technology is implemented. Both the dynamic governing equations including the temperature effects and the related boundary conditions are obtained via the application of Hamilton’s principle. Toward the end of controlling the oscillations and prevent the occurrence of the thermal flutter instability, a feedback control capability based on the use of the piezoelectric induced strain actuation is implemented. The performance of its implementation considered in conjunction with that of the structural tailoring are highlighted, and final conclusions are outlined.
A Rapid Method for the Extraction of Radioiodide from Urine
THE extraction of radioiodide from urine is important in radioiodide therapy, since without it the large quantities of highly radioactive urine which accumulate must be stored until the activity decays sufficiently to allow disposal.