Nonlinear Control Design Blockset

A System Identification Problem

The next example, ncdtut2, shows one technique for using the Nonlinear Control Design Blockset to perform closed loop system identification. Specifically, we want to estimate the mass and length of the pendulum in a variation of the popular inverted pendulum problem. The physical system contains a cylindrical metal rod attached to a motor driven cart to allow for rotation about only one axis. We mount the cart on a linear track to create a stabilizable problem as shown below.

The rod initially has a mass of 0.21kg and a length of 0.61m and is stabilized via LQR control. The Appendix explains both the equations of motion for the system and the design of the LQR controller.

With the LQR controller stabilizing the system, we stick a clay ball to the top of the rod, thus changing the effective pendulum mass and length. Now we want to estimate this new pendulum mass and length.

Adding Uncertainty

Nonlinear Control Design Blockset Startup