The importance of implementation issues in achieving control goals

The development of a control solution almost always involves the initial synthesis of a simplified control law based on consideration of an idealised linear formulation. The control law is then augmented in order to address practical implementation issues neglected during the previous stage. The performance achieved by a controller often depends extremely strongly on the extent to which the implementation issues are resolved. Moreover, owing to the continuing pressure for the development of high performance control systems coupled with the trend towards operating closer to the physical constraints on the system, these implementation issues are likely to become of even greater importance. In this paper, strategies for adequately resolving some common implementation issues are considered. Since the implementation issues encountered in wind turbine regulation have many features in common with those encountered in a broad range of applications, including the aerospace field, in order to be specific the strategies are discussed with reference to wind turbine regulation. The implementation issues considered include the compensation of the highly nonlinear aerodynamics, minimising transients during changes in the mode of controller operation and accommodation of the hard limits on actuator accelerations (or torques) and velocities