Integrated design optimization of structural bending filter and gain schedules for rocket attitude control system

TL;DR

This paper introduces an integrated optimization framework for designing gain schedules and bending filters to enhance the stability and performance of rocket attitude control during ascent, considering complex dynamic models.

Contribution

It presents a novel integrated design optimization method for gain schedules and bending filters, accounting for multiple dynamic factors in rocket ascent control.

Findings

Optimized gain schedules improve stability margins.

Bending filter design reduces peak bending mode response.

Framework effectively stabilizes rocket pitch/yaw during ascent.

Abstract

This paper proposes an integrated design optimization framework for the gain schedules and bending filter for the longitudinal control of a rocket during its ascent flight. Dynamic models representing the pitch/yaw motion of a rocket considering the elements such as the rigid body dynamics, aerodynamics, sloshing, bending, sensor/actuator, and flight computer are introduced. The linear proportional and differential (PD) control law with scheduled (time-varying) gains and bending filter parameters are identified as key decision variables for stabilizing the pitch/yaw motion of the rocket. The integrated optimal design problem that determines the decision variables to minimize the worst-case peak associated with the first bending mode with constraints on the stability margins during the flight of the rocket is mathematically formulated. A case study on design of gain schedules and bending filter for an actual sounding rocket using the proposed framework is conducted to demonstrate its effectiveness.