“…In recent years, the model of PSS has been broadly applied in computer science, biology, mechanical engineering and so on. More and more scholars are paying close attention to the stability of PSS, see [4,5,6,7,8,9]. Consequently, the approaches of common copositive Lyapunov function [10,11,12,13,14] and multiple copositive Lyapunov function [15,16,17] were proposed to study the stability of PSS.…”