Perpustakaan Digital ITB

The advancement of aerospace technology, particularly in the realm of space exploration, has reached remarkable heights. A significant stride in this domain is the development of Vertical Takeoff Vertical Landing (VTVL) launch vehicles, wherein a major portion of the vehicle is reusable, making it more sustainable and cost-effective. This feat has been successfully demonstrated by Falcon 9. The Falcon 9 utilizes thrust vectoring control (TVC) to achieve vertical landing, a method that involves manipulating the direction of the thrust vector. However, implementing TVC for autonomous landing poses several challenges, particularly in designing a control system for the vehicle during the landing phase. Based on these challenges, this research thesis aims to contribute to the advancement of VTVL launch vehicles by proposing a novel approach to modeling the vehicle’s dynamics and designing controllers, thereby fostering the development of more sustainable and cost-effective launch vehicles. This research thesis will introduce a framework to construct a dynamic simulation of the Falcon 9 First Stage Booster with Interstage using a multibody approach. This involves creating a 3-D representation model and employing numerical methods to solve the dynamic system’s state at each simulation time step. Leveraging the linearized equation of motion, an optimal controller will be designed using the Linear Quadratic Regulator (LQR) approach. The designed controller will then undergo testing in the nonlinear multibody dynamic simulation under various case conditions, including all engine operatives, one engine operative, positive and negative initial angle of attack condition, and simulation with noise and disturbance. In this scenario, the controller is designed to track the target positions of 680 m for downrange distance and 20 m for altitude. From the test result, it achieved a steady state final landing position of 680.0 m for downrange distance and 19.3 m for altitude in the all-engine operative condition, and 679.9 m and 20.5 m, respectively, in the one-engine operative condition. Moreover, the controller successfully executed the landing maneuver within the range of -11° to 4° of the initial angle of attack. For the condition where sensor noise and disturbance in the form of severe turbulence is present, it achieved a mean downrange distance of 680.5 m with a standard deviation of 5.482 m and a mean altitude of 20.64 m with a standard deviation of 0.7969 m.