ℒ1 adaptive controller of VEGA Launcher subject to flexible modes

• Published in: INCAS bulletin Vol. 16; no. 4; pp. 81 - 89
• Main Authors: NAJI, Naji Anees Muqdad, STOICA, Adrian-Mihail
• Format: Journal Article
• Language: English
• Published: Bucharest INCAS - National Institute for Aerospace Research "Elie Carafoli" 06.12.2024; National Institute for Aerospace Research “Elie Carafoli” - INCAS
• Subjects: Actuators; Adaptive systems; aerodynamic load vs. mach number; Automatic control systems; Butterworth filters; Closed loop systems; Control stability; Control systems design; Controllers; Design; Elastic analysis; Elastic deformation; flexible launcher model; Inertial platforms; Launch vehicles; Launchers; Motion stability; Payloads; Pitch (inclination); robust stability; Thrust vector control; Vehicles; ℒ1 adaptive controller
• ISSN: 2066-8201; 2247-4528
• DOI: 10.13111/2066-8201.2024.16.4.8

Flexible launch vehicle modes contribute to the deterioration of its stability performance. For this reason, their influence must be considered when designing and validating appropriate solutions for its automatic control system. The first three bending modes are the most relevant for control system design and analysis. Next, considerations regarding the elastic modes of the Vega actuator, used in the simulations performed throughout this study, are presented. The IMU (Inertial Measurement Unit) measurements providing attitude angles and angular rates are strongly corrupted by the local elastic deformations resulting from structural flexibility. These measurements are fed back to the TVC (Thrust Vector Control) system which controls the pitch and the yaw motion of the vehicle. The design methodology for this control system is based on an ℒ1 adaptive technique incorporating a Butterworth filter guarantees good stability performances for wide variations of the launcher’s dynamics parameters.