ARD-Like Gain Scheduled Control for Re-Entry Vehicle

Many in house researches have been performed, and are still under development, at ASTRIUM Space Transportation to develop 3 degrees of freedom attitude control law for lifting body re-entry vehicle during hypersonic phase. Main objective of this paper is to present researches results based on adaptation of gain scheduled control law that was initially developed for ARD capsule to lifting body re-entry control. It includes detailed definition, development and validation for lifting body re-entry application. Main interest of this so-called ARD-like control law is that all control gains are computed using analytic relations based on simplified models that may be implemented on-board. Final gain scheduling is reduced to 12 parameters linked to objective variation along the flight which means that ARD-like control law is robust to flight conditions. However, despite its robustness, such a control law still needs iterative process to respect all performance and stability objectives for the large number of varying parameters with huge domain of uncertainties. Among promising control method, LPV seems perfectly suited for such kind of problem and studies are on going to improve re-entry control design. Thus, preliminary results on longitudinal control laws using polytopic modeling and LPV control design are also briefly presented in this paper and compared to ARD-like gain scheduled control law for European re-entry vehicle. Studies are still on going to extend these results to full 3 degrees of freedom control.