1. College of Engineering Nanjing Agricultural Univ., Key Laboratory of Intelligent Agricultural Equipment of Jiangsu Province Nanjing 210031 P.R. China
2. Nanjing Institute of Agricultural Mechanization Ministry of Agriculture and Rural Affairs Nanjing 210014 P.R. China
3. Jiangsu Provincial Agricultural Reclamation and Development Corporation Nanjing 210019 P.R. China