Dual Youla parameterisation

A different aspect of using the parameterisation of all systems stabilised by a given controller, i.e. the dual Youla parameterisation, is considered. The relation between system change and the dual Youla parameter is derived in explicit form. A number of standard uncertain model descriptions are considered and the relation with the dual Youla parameter given. Some applications of the dual Youla parameterisation are considered in connection with the design of controllers and model/performance validation.