1, The research on gearbox fault and vibration mechanism is not thorough enough, most of them are qualitative conclusions. There is considerable difficulty in establishing a complete mathematical mechanics model for quantitative analysis.

2, the current diagnostic methods are mostly based on the tank vibration signal research, from the modern signal processing technology in-depth study, without the combination of other diagnostic methods, often leading to misdiagnosis of diagnosis;

In the current theoretical research, the gearbox is generally researched as a linear system. However, in the gearbox fault test rig and engineering practice, the gearbox vibration involves many nonlinear factors.

4, gearbox fault diagnosis expert knowledge base is very short, knowledge base reliability and promotion of poor, many diagnostic examples can not be expressed as a common knowledge rules;

5, theory and practice are largely out of line, all kinds of vibration signal processing techniques such as research papers, laboratory tests made some success or breakthrough, but often can not meet the requirements in practice.