ℋ₂ static output feedback switching function design based on a time-varying Lyapunov function approach

This paper treats the control design of an output-dependent switching function for discrete-time switched linear systems, without considering the synthesis of any additional dynamic structure. The conditions are based on a convex, but time-varying, Lyapunov function and are expressed in terms of Linear Matrix Inequalities (LMIs). The state feedback switching function design can be obtained as a particular case and is simpler to handle from theoretical and numerical viewpoints compared to other methods available in the literature, as for instance, those based on Lyapunov–Metzler inequalities. The novelty of the proposed control methodology is the adoption of a time-varying Lyapunov function, which together with the presence of a key matrix, allow us to treat the static output feedback control design, taking into account a guaranteed H2 performance cost. Academic examples are used for comparison and illustration. The proposed control technique is experimentally validated in an active suspension system representing a quarter-vehicle.