LAUSR

ABSTRACT This paper considers strictly positive real (SPR) controller design via direct minimisation of an upper bound on the closed-loop norm. To realise a tractable design problem, an observer-based control structure is assumed and a state-feedback gain that renders the controller SPR while minimising an upper bound on the closed-loop norm is sought. A convex optimisation problem subject to linear matrix inequality (LMI) constraints is realised by using a common Lyapunov variable. By using dilated LMIs, a partial separation of design variables is possible thereby enhancing design freedom. Numerical results comparing the common Lyapunov variable solution, the dilated LMI solution and method presented in the literature are included.