Development of an LQR Controller for a Jet Vanes Thrust-Vectored Rocket

This paper outlines the task of developing a control system for a rocket controlled by jet vanes, small diamond-shaped actuators placed in exhaust flow of a motor to manipulate the rocket’s attitude along its roll and yaw axes. With usage of a custom aerodynamic model, an in-house 6-DOF simulation was written to analyze the rocket trajectory. Based on the rocket’s flight profile, several trim points were established to linearize rocket dynamics for use of a Linear Quadratic Regulator (LQR) controller. Using on the rocket’s state in flight, the controller selects a gain matrix and computes optimal roll and yaw moments to achieve a specified desired attitude. The desired attitude is comprised of a zero roll angle and a variable setpoint yaw angle changes. A Monte Carlo analysis was performed to ensure the controller met its goals under various rocket parameters and flight conditions. The result is a simulation-verified control system architecture as well as a step-by-step process to developing LQR controllers for any rocket and actuator configuration.