Designing a Robust Nonlinear Dynamic Inversion Controller for Spacecraft Formation Flying

Inseok Yang,Dongik Lee,Dong Seog Han

doi:10.1155/2014/471352

Inseok Yang, Dongik Lee + Show 1 more

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https://doi.org/10.1155/2014/471352

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Abstract

The robust nonlinear dynamic inversion (RNDI) control technique is proposed to keep the relative position of spacecrafts while formation flying. The proposed RNDI control method is based on nonlinear dynamic inversion (NDI). NDI is nonlinear control method that replaces the original dynamics into the user-selected desired dynamics. Because NDI removes nonlinearities in the model by inverting the original dynamics directly, it also eliminates the need of designing suitable controllers for each equilibrium point; that is, NDI works as self-scheduled controller. Removing the original model also provides advantages of ease to satisfy the specific requirements by simply handling desired dynamics. Therefore, NDI is simple and has many similarities to classical control. In real applications, however, it is difficult to achieve perfect cancellation of the original dynamics due to uncertainties that lead to performance degradation and even make the system unstable. This paper proposes robustness assurance method for NDI. The proposed RNDI is designed by combining NDI and sliding mode control (SMC). SMC is inherently robust using high-speed switching inputs. This paper verifies similarities of NDI and SMC, firstly. And then RNDI control method is proposed. The performance of the proposed method is evaluated by simulations applied to spacecraft formation flying problem.

Highlights

Spacecraft formation flying (SFF) problem is a cooperative control problem that distributes the task of a single spacecraft into a group of spacecrafts to improve the robustness of a space mission by decreasing the possibility of a single failure that can lead to total mission loss [1,2,3]
Numerical simulations are conducted to evaluate the performance of the proposed robust nonlinear dynamic inversion controller
nonlinear dynamic inversion (NDI) with the proportional type of the desired dynamics is designed as a primary controller for SFF

Summary

Introduction

Spacecraft formation flying (SFF) problem is a cooperative control problem that distributes the task of a single spacecraft into a group of spacecrafts to improve the robustness of a space mission by decreasing the possibility of a single failure that can lead to total mission loss [1,2,3]. For this reason, SFF has attracted considerable interest owing to its advantages of increased mission success probability and increased feasibility, flexibility, and so forth.

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Conclusion