Model reduction for unstable LPV systems based on coprime factorizations and singular perturbation

This paper proposes a reduction method of unstable linear parameter varying systems. We generalize a singular perturbation method for linear time invariant systems by approximating the contractive right coprime factorizations to reduce parameter varying realizations which are not quadratically stable. Based on the reduced-order model the low-order parameter varying controllers are designed. Effectiveness of the proposed model reduction is verified by applying it to LPV control of an aircraft model. The closed-loop performance with the low-order LPV controller found by proposed method is compared with balanced truncation method of Wood.