Advanced Capstone Spacecraft Dynamics and Control Project

Overview

This capstone course is the 3rd and final course of the specialization Advanced Spacecraft Dynamics and Control. It assumes you have completed the prior courses on "Attitude Control with Momentum Exchange Devices" and "Analytical Mechanics for Spacecraft Dynamics". This project course investigates the dynamics of a complex spacecraft system where there is a rigid hub onto which a hinged panel is attached. This simulates a spacecraft with a time varying geometry. First, the three-dimensional kinematics of this system are explored. Analytical relationships of the body and panel position and velocity states are derived, and the center of mass properties of this system are explored. Next, a simplified system is used to use Lagrange's equations of motion to predict the dynamical response. With these differential equations we are then able to apply attitude control torques and investigate the rotational response if the spacecraft hub has a spring-hinged panel attached. Two open-loop control torque solutions are investigated. The classical minimum time bang-bang control solution is applied first, illustrating how such a control can yield unwanted panel oscillations. Finally, a filtered version of the bang-bang control is applied to illustrated how the panel oscillations can be significantly reduced at the cost of a slightly longer nominal maneuver time.

Syllabus

Introduction to the Capstone Project

Welcome to the capstone project of the course sequence on advanced spacecraft dynamics and control.

3D Spacecraft Hub-Panel System

In this lesson we study a spacecraft system that contains a rigid hub with a hinged solar panel. Here the hub and panel center of mass locations are free to move relative to the spacecraft system center of mass. Fundamental properties of the dynamical description are derived.

Planar Rotation Control using Bang-Bang and Filtered Control Solutions

In this module we develop the differential equations of motion of the hub-panel spacecraft system that is constrained to rotate about a single axis. Two different open-loop torque solutions are applied to reorient the spacecraft from rest to a new stationary attitude. The impact of filtering a classical bang-bang control solution is investigated by apply a first-order low-pass filter to the control input.