Performance and robustness trade-off capabilities for the VEGA launcher TVC system

This article presents a methodological synthesis framework based on the structured H∞ approach for the design of atmospheric launcher TVC systems, using the VEGA launcher as the application case. The main advantage of this framework is that the TVC design can be recast into a formal multi-objective optimisation problem in which robust stabilisation, disturbance rejection and performance minimisation are managed in a simultaneous fashion. This article illustrates how the proposed framework can be guided to favour a specific trade-off performance objective via proper choice of the design weighting functions. The capabilities to manage different control strategies are demonstrated via several structured H∞ designs which are tailored to maximise specific performance metrics (i.e. loads, drift, attitude errors). These controllers are analysed and compared through high-fidelity, nonlinear time-domain Monte Carlo simulations of the VEGA atmospheric flight.