Robust control for reusable rockets via structured h∞ synthesis

This paper discusses the problem of synthesizing robust controllers for reusable rockets during the aerodynamic descent phase. Emphasis is given to a well-established subset of methods, specifically robust control techniques based on the H∞ concept. A thorough description of how this family of methods can be used for the descent phase of reusable rockets is provided, together with a comparison of the fulland structured-version of H∞ methods. The methodology, the problem faced and the performance that can be obtained are discussed. Some results are shown for CALLISTO, a reusable rocket demonstrator jointly developed by DLR, JAXA, and CNES.