Controlling a launch vehicle at exoatmospheric flight conditions via adaptive control allocation

Yıldıray Yildiz

doi:10.3906/elk-2001-123

Abstract

Controlling a launch vehicle at exoatmospheric flight conditions via adaptive control allocation

Highlights

At exoatmospheric conditions, the conventional aerodynamic control surfaces cannot be used since forces and moments cannot be generated in the absence of dynamic pressure
A control system can treat Reaction control jets (RCJ) as continuous actuators, with the help of pulse modulation, or they can be used with a bang-bang control approach, where the jets are fired on and off based on a phase-plane analysis [2]
A control allocation solution is proposed for the control of launch vehicles in exoatmospheric conditions

Summary

Introduction

The conventional aerodynamic control surfaces cannot be used since forces and moments cannot be generated in the absence of dynamic pressure. A control system can treat RCJs as continuous actuators, with the help of pulse modulation, or they can be used with a bang-bang control approach, where the jets are fired on and off based on a phase-plane analysis [2]. One way to allocate redundant actuators is to use the pseudo-inverse of the input matrix to produce individual actuator signals [12,13,14] Another method is defining a cost function as a difference between the desired and achieved. A control allocation based control framework is proposed for launch vehicles equipped with RCJs controlled using pulse width modulation (PWM). Holds, where the trace operation is referred to as tr( · )

Plant dynamics

Control system design

Controller

Simulation results

Initialization of the control allocation parameters

Summary and discussion