This is one of a series of white papers on systems modelling, analysis and control, prepared by Control-Systems-Principles.co.uk to give insights into important principles and processes in control. In control systems there are a number of generic systems and methods which are encountered in all areas of industry and technology. These white papers aim to explain these important systems and methods in straightforward terms. The white papers describe what makes a particular type of system/method important, show how it works and then demonstrates how to control it. The control demonstrations are performed using models of real systems designed by Peter Wellstead, and which have been developed for manufacture by TQ Education and Training Ltd in their CE Range of equipment. This white paper is about the application of robust control to the Ball and Beam System.