During machining some ultra-intense and special-shaped parts, unstability and surface ablation often turn up. Some large and heavy parts are often machined with heavy duty NC machine tool. For avoiding the processing defects of the above parts, an online monitoring, diagnosis and control system is designed for heavy duty NC machine tool. The system can online monitor the operation condition of heavy duty NC machine tool and real-time control the processing. Some methods of signal analysis and processing are adopted such as spectrum analysis, wavelet analysis, Wigner-Ville distribution and Artificial Neural Network etc. The system is developed with C language and Qt based on Linux operation system. Optical fiber communication is adopted between industrial computer and NC system. Experiment platform of the system is machining an aircraft landing gear with five-axis NC machine tool. The scheme is verified feasible after preliminary test.

In the monitoring of a NC machine tool (NCMT), signal analysis is one of the most important considerations. In order to process multi-information in a comprehensive way and integrate with NC systems in a stable way, a signal analysis module (SAM) with various feature parameters programmed in C language is proposed. Experiments are carried out in Huazhong NCMT to verify the validity of the presented SAM. The work described in this paper can be applied to almost all NC systems and industrial computers with different operating systems (OSs).