Port-Hamiltonian Mathematical Model of a Fluid Ring Attitude System

Juan Cristobal Alcaraz Tapia,Carlos E Castañeda,Héctor Vargas-Rodríguez

doi:10.3390/en14216906

Abstract

In this article, we propose a mathematical model using the port-Hamiltonian formalism for a satellite’s three-axis attitude system comprising fluid rings. Fluid rings are an alternative to reaction wheels used for the same purpose, since, for the same mass, they can exert a greater torque than a reaction wheel as the fluid can circulate the periphery of the satellite. The port-Hamiltonian representation lays the foundation for a posterior controller that is feasible, stable, and robust based on the interconnection of the system to energy shaping and/or damping injection components, and by adding energy routing controllers. The torques exerted by the fluid rings are modeled using linear regression analysis on the experimental data got from a prototype of a fluid ring. Since the dynamics of turbulent flows is complex, the torques obtained by the prototype lead to a simpler first approach, leaving its uncertainties to a controller. Thus, the attitude system model could be tested in a future prototype before considering a spatial environment.

Highlights

Ciencias Exactas y Tecnología, Centro Universitario de los Lagos, Universidad de Guadalajara, Citation: Alcaraz Tapia, J.C.; Abstract: In this article, we propose a mathematical model using the port-Hamiltonian formalism for a satellite’s three-axis attitude system comprising fluid rings
Since the mass of a fluid ring is concentrated in the periphery, it can exert a greater torque onto a satellite than a reaction wheel of similar mass
If the elements of the vector p f are substituted into the equation representing the torques exerted by the fluid rings (16), it can be written: ṗ1 = u1 (37a) ṗ2 = u2 (37b) ṗ3 = u3 (37c)

Summary

Introduction

Ciencias Exactas y Tecnología, Centro Universitario de los Lagos, Universidad de Guadalajara, Citation: Alcaraz Tapia, J.C.; Abstract: In this article, we propose a mathematical model using the port-Hamiltonian formalism for a satellite’s three-axis attitude system comprising fluid rings. Some devices use the Earth’s magnetic field to achieve attitude corrections [11,12,13], magnetic torquing is a good option for small satellites in low Earth orbits These kinds of systems are lightweight, inexpensive, and require low power, but, as a limitation, the torque exerted is perpendicular to the local geomagnetic field vector. Another momentum exchange device [14] uses the motion of a fluid in a circuit to exert a torque onto a spacecraft. In the work of Xiao [16], it is considered that the permanent magnets mentioned by Varatharajoo might influence the sensitive equipment, influencing the normal work of the satellite

Methods

Results

Conclusion