Where possible, the Nonlinear Control Design Blockset provides visual cues to help you formulate problems and inform you about the progress of an optimization. Error checks have been included where possible. Messages and hints are displayed in the MATLAB command window and in dialog boxes. Only engineering experience with your application's particular problem can guide you in deciding on a control structure. Often solutions to similar problems provide a good starting point for new problems. The evolution of your control design may take different paths and your final control structure may differ from the structure with which you began. Because the Nonlinear Control Design Blockset permits you to specify the control structure, it can be valuable throughout the control design process. Following is a list of typical problems and recommendations for dealing with them.