Robust control is a branch of control theory that focuses on ensuring that a control system performs satisfactorily in the presence of uncertainties or disturbances in the system. The goal of robust control is to design controllers that are able to maintain stability and performance even when the system parameters change or are unknown. In robust control, the controller is designed to be resilient to uncertainties, modeling errors, external disturbances, and variations in system operating conditions. This is typically achieved by incorporating a margin of safety in the controller design, such as using robust stability criteria, robust performance criteria, or robust optimization techniques. Overall, robust control is used in a wide range of applications, such as aerospace systems, automotive control, robotics, chemical processes, and power systems, where the ability to maintain performance in the face of uncertainties is important.