[1] Beihang Univ, Sch Automat Sci & Elect Engn, Res Div 7, Beijing 100191, Peoples R China
[2] Beihang Univ, Sci & Technol Aircraft Control Lab, Beijing 100191, Peoples R China
[3] Univ Pretoria, Dept Elect Elect & Comp Engn, ZA-0028 Pretoria, South Africa