Variable Structure Switching Controller

This paper presents results of an exploratory research in a variable structure control strategy that switches between two state feedbacks. Published results using computer simulations have shown that such switching strategies can have significant advantages in fuel consumption and performance over a fixed state feedback regulator. Moreover, it can guarantee asymptotic stability in the absence of sliding motion, even if one of the regulators is actually unstable. This exploratory research intends to test the application of the concept to other systems where fuel economy may not be a primary concern. This paper expands on published results in several aspects. First, the paper develops a simple criterion that can be used to predict the effectiveness of using switching control. Second, the paper verifies the existence of sliding motion for this application and resolves, for the first time, the issue of stability during sliding for switching state feedbacks. Third, it uses as test bed an experimental laboratory unit and compares results of both computer simulation and laboratory measurements. The selected test bed is the classical inverted pendulum system.