# Structured H∞ Control for Spacecraft with Flexible Appendages

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## Abstract

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## 1. Introduction

## 2. System Model Case and Control Analysis

- Maintain at least 5 dB gain margin and 20 deg phase margin.
- Provide at least 6 dB gain suppression (roll off) of the high-frequency spacecraft structural modes at 14 Hz.
- Provide at least 20 dB additional disturbance attenuation at both 0.12 Hz and 0.66 Hz with respect to the original design.
- Maintain the bandwidth (the open-loop gain crossover frequency) close to 1.5 Hz.

## 3. Design of Structured H∞ Control

#### 3.1. Structured Controller Setting

#### 3.2. Selection of Performance Weighting Functions

#### 3.3. Parameter Optimization of Structured Controller

## 4. Simulation Performance Analysis

## 5. Conclusions

## Author Contributions

## Funding

## Conflicts of Interest

## References

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**Figure 11.**Open-loop simulation comparison between the structured integrated controller and traditional H-inf controller.

**Figure 12.**Simulation comparison of time-domain response between the structured integrated controller and traditional H-inf controller.

${\mathit{K}}_{\mathit{i}}/\mathbf{kg}\times {\mathbf{m}}^{\mathbf{2}}$ | ${\mathit{\omega}}_{\mathit{i}}/\mathbf{Hz}$ |
---|---|

0.018 | 0.110 |

0.012 | 0.432 |

0.057 | 0.912 |

0.024 | 10.834 |

0.155 | 12.133 |

−1.341 | 13.201 |

−1.387 | 14.068 |

−0.806 | 14.285 |

−0.134 | 15.264 |

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**MDPI and ACS Style**

Zhang, Y.; Pang, A.; Zhu, H.; Feng, H.
Structured H∞ Control for Spacecraft with Flexible Appendages. *Entropy* **2021**, *23*, 930.
https://doi.org/10.3390/e23080930

**AMA Style**

Zhang Y, Pang A, Zhu H, Feng H.
Structured H∞ Control for Spacecraft with Flexible Appendages. *Entropy*. 2021; 23(8):930.
https://doi.org/10.3390/e23080930

**Chicago/Turabian Style**

Zhang, Yuntian, Aiping Pang, Hui Zhu, and Huan Feng.
2021. "Structured H∞ Control for Spacecraft with Flexible Appendages" *Entropy* 23, no. 8: 930.
https://doi.org/10.3390/e23080930