“…Indeed, the switched system is very useful, because it can describe a large number of practical systems including flight control systems, network control systems, DC/DC converters and so on [14]. In the past decades, the stability, controllability and observer design of switched systems have been studied extensively [15][16][17][18][19][20][21]. However, in the field of switched system UIO designs, there are only a few results can be found in literature [22][23][24][25][26].…”