Theory and Application of Nonlinear Control

In practice, most of control systems, especially mechanical systems, are not quite linear although they are often approximated by linear equations mainly for mathematical simplicity. The major parts of current available control methods do, however, suffer from the fact that they are mainly applicable to linear systems. This makes these methods sensitive to nonlinearities. The nonlinear systems can be also linearized in order to use the linear control theory to nonlinear systems. But this method can only be applied to the cases that the degree of non-linearity is small. Many publications have in recently appeared in literature concerning nonlinear systems control. However, most of the publications only concern development of control theory. Our research on nonlinear control should focus on application. One of the test facilities is the two-link hydraulic test robot. The candidates of nonlinear control methods include:
- Adaptive Control
- Feedback Linearization
- Variable Structure Control
- Fuzzy Logic Control