Nonlinear Control Design Blockset

Multimode Control

Multimode control concerns designing one or more controllers for a plant as it transitions over a wide range of dynamic behavior. Typically you make a linear approximation of the plant at a number of operating points (plant conditions) and then generate a controller for each operating point. The plant models at the operating points often have different dynamic order and the controllers for each operating point generally have different structure and/or order. Multimode control also considers the design of the logic (supervisory control), which switches between the various controllers designed for each operating point. To model a multimode controller in Simulink, use switch blocks to toggle among the various plant and controller models according to the operating conditions of the plant. Use logic blocks (from the extrlog directory) to create the supervisory control that manages the switches.

The Nonlinear Control Design Blockset allows you to design multimode controllers and simplifies the process in two ways: by providing a means to tune the switching logic and by decreasing the number of controllers you need to generate. As with other problems, you can design your controller using the actual nonlinear plant model instead of a number of operating point linear approximations. Not only does this reduce the amount of verification that you must perform once the optimization produces results, but it also allows you to tune the switching logic parameters. In the case of multimode control, the ability to design nonlinear controllers may not only create the possibility for improved performance over linear control, but may decrease the number of controller you must generate since a single nonlinear controller may be applicable to more than one operating point.

MIMO Systems

Gain Scheduling