Control Strategies for Large Space Structures: Application to Orbiting Solar Reflectors
- Paper ID
97276
- DOI
- author
- company
University of Glasgow
- country
United Kingdom
- year
2025
- abstract
With the increasing global demand for clean energy, orbiting solar reflectors (OSRs) can augment electricity generation from terrestrial solar power farms (SPFs) by reflecting sunlight onto them at times of day when little to no electricity can otherwise be generated (e.g. dawn/dusk). An OSR is a large reflective membrane with 3-axis attitude control. The proposed OSR in this work is hexagonal in shape with a side length of 250 m, as detailed in the SOLSPACE reference architecture [1]. This paper will directly address the challenges of active control for energy from space. Given the large reflector size, one of the major challenges in attitude control is the inherent flexibility of the structure. The excitation of flexible modes during nominal operations can quickly become problematic if steps are not taken to limit these excitations, both in terms of pointing of the OSR and the impact on energy delivery. A new “vibration maintenance” phase of operation for the OSR concept, which allows time for the structural vibrations to be damped before active SPF tracking can be resumed, will then be established. Assessment of the most effective control algorithms for minimizing structural vibrations will allow the OSR to be operational for longer before being taken offline for this vibration maintenance phase. This work will employ control algorithms which allow the targeting of problematic flexible modes, such as linear quadratic regulators (LQR) and model predictive control (MPC), to assess their efficacy in maintaining the required pointing requirements while also limiting flexible mode excitation. The structural dynamics are modelled using a truncated modal coordinate method and the attitude kinematics are parameterized using modified Rodrigues parameters (MRP). The MRP parameterization allows for the linear models used in controller design to be valid for a higher range of pointing error angles in the full nonlinear simulation. [1] A. Viale, O. Çelik, T. Oderinwale, L. Sulbhewar, and C. R. McInnes, “A reference architecture for orbiting solar reflectors to enhance terrestrial solar power plant output,” Advances in Space Research, vol. 72, no. 4, pp. 1304–1348, Aug. 2023, doi: 10.1016/j.asr.2023.05.037.