1. 1) College of Mechanical and Electrical Engineering, Hebei Agricultural University, Baoding, 071000/China; 2) Research Institute of Mechanical and Electronic, Hengshui University, Hengshui, 053000/China
2. College of Mechanical and Electrical Engineering, Hebei Agricultural University, Baoding, 071000/China
3. Research Institute of Mechanical and Electronic, Hengshui University, Hengshui, 053000/China