Control Synthesis Along Uncertain Trajectories Using Integral Quadratic Constraints

TL;DR

This paper introduces a robust control synthesis method for nonlinear systems along uncertain trajectories, leveraging integral quadratic constraints to improve performance under perturbations, demonstrated on a space launcher pitch tracker.

Contribution

It develops a new robust control synthesis approach that accounts for trajectory perturbations using IQC-based linearization, enhancing nonlinear system robustness.

Findings

Controller designed for a space launcher pitch tracker shows improved robustness.

The IQC-based method outperforms traditional robust linear time-varying approaches.

Feasibility demonstrated through successful simulation results.

Abstract

The paper presents a novel approach to synthesize robust controllers for nonlinear systems along perturbed trajectories. The approach linearizes the system with respect to a reference trajectory. In contrast to existing methods rooted in robust linear time-varying synthesis, the approach accurately includes perturbations that drive the system away from the reference trajectory. Hence, the controller obtained in the linear framework provides a significantly more robust nonlinear performance. The calculation of the controller is derived from robust synthesis approaches rooted in the integral quadratic constraints framework. The feasibility of the approach is demonstrated on a pitch tracker design for a space launcher.