Joint robust structured design of VEGA launcher’s rigid-body controller and bending filter

This article presents the design of a robust atmospheric control system for the rigid and flexible motion of the VEGA launcher. Unlike the state-of-practice where the design of the rigid-body controller and bending filters are traditionally addressed in a sequential and iterative manner, in this work they are first parametrized following a classical control architecture and then tuned simultaneously using the structured H∞ optimization framework. This joint design greatly simplifies the synthesis process and reduces the tuning effort across launch missions. The capabilities of this advanced synthesis framework are exemplified through a design example using the real VEGA 5 flight mission data. The results show that the structured H∞ synthesis technique, and proposed methodology, improve the performance and robustness of the launcher, while simplifying the classical current VEGA TVC architecture. This represents a paradigm change in terms of the control design process followed by VEGA, but not in terms of the design objectives and accumulated flight experience heritage by the actual VEGA GNC team.