ABSTRACT
First, all methods presented thus far in this text relate to the design, modeling, simulation, and implementation of feedback controllers, that is, controllers that operate on the error between the desired command and actual "feedback." In all cases, before and including this chapter, the skills for acquiring/developing accurate physical system models (and a good understanding of the system) are invaluable. Although in some cases the model is only indirectly related to the actual controller design, the knowledge of the system (and hence the model) will always help in developing the best controller possible. In general for feedback controllers, regardless of algorithms or implementations, the goal is to design and tune them to capably handle all the system unknowns (always present), which cause the errors in our system. These errors arise primarily from disturbances and incorrect models.
