1. School of Power and Energy , Northwestern Polytechnical University , Xi’an 710072 , Shaanxi , China
2. School of Aircraft Engineering , Xi’an Aeronautical Institute , Xi’an 710077 , Shaanxi , China
3. School of Automation , Northwestern Polytechnical University , Xi’an 710072 , Shaanxi , China
4. School of Measuring and Optical Engineering , Nanchang Hang Kong University , Nanchang 330063 , China