Robust Stabilization of Cart Inverted Pendulum System by 2-Rate Controller

In a Multi(2)-rate controller the input and output of the plant are sampled at different rates. In this context, it is important to note that several attempts have been made in the literature to achieve zero-placement using 2-rate control. These attempts, however, involved only the fast-input type of control which, unfortunately, yields unacceptable oscillations in the output. The fast-output type, on the other hand, does not have this problem inherently, but it's zero placement capability has been established recently by viewing it from a 2-Periodic perspective. This zero-placement capability of 2-rate control ensures robustness of the compensated system in terms of satisfactory gain margin (GM) values. This work proposes a 2-rate controller to stabilize the cart inverted pendulum system (CIPS) and shows that the GM of the overall system is improved considerably as compared to the results obtained using LDTI controllers.