A Unified Framework To Design Time-Constrained Control Systems and its Application to Attitude Control of a Rigid Spacecraft

This paper presents a unified educational framework for introducing and analyzing different time-constrained control methodologies for nonlinear systems. The formulation covers asymptotic, finite-time, fixed-time, predefined-time, and prescribed-time control approaches. For each methodology, the control design requirements are outlined, followed by the controller formulation and stability analysis using a generic second-order strict-feedback nonlinear system model. This unified treatment allows for a cohesive learning journey to understand the theoretical foundations and relative merits of the various time-constrained control strategies. To illustrate the practical utility of these techniques, the frameworks are applied to the attitude control problem for a rigid spacecraft. Comparative simulation results highlight the convergence behavior and tracking performance achieved by each method on this aerospace vehicle application. The unified presentation provides a pedagogical approach for the systematic study of time-constrained control methodologies of relevance for aerospace systems. This formulation can serve as an educational resource in aerospace control curricula for exposing students to these advanced nonlinear control techniques. Copyright (C) 2024 The Authors. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/)