Reliability Prediction Of The CNC System And The Research On Reliability Of CNC Software

The CNC processing is the key technology of modern machinery manufacturing. Alongwith the development of the technology of computer and automation, CNC machine plays amore and more important role in the modern industry, and becomes a major mark for thelevel of a country’s manufacturing. The CNC system as the central part of CNC machineplays an important part in the function of the whole CNC machine. The main difference ofCNC system between domestic products and the import products is the reliability. So thenation inputs a great deal of research on the reliability of CNC system. This paper mainlydiscussed the reliability prediction of the CNC system and the reliability of CNC software,combining with the Major National Science and Technology Projects—“Research onreliability technology of CNC system and reliability on the operation of heavy machine（2009ZX04014-013）”.Predicting the reliability of CNC system accurately will provide a metric for thefollowing use and design, and be the foundation for improving the design in the future. Thispaper collected the fault datum of a certain type CNC system according to the field tests.Rebuilt a neural network model containing three tiers to predict the reliability of the certaintype CNC system, the results indicated that the model was effective for the reliabilityprediction. This will do great well for directing the upgrade, research and development ofthe CNC system.Nowadays, the modern CNC system is moving to the direction of high-speed,high-precision, high-efficiency, multi-functional and intelligent. Software is one of theimportant part of the CNC system. The scale, calculation and function of the software arebecoming so powerful that it is more and more difficult for ensuring the reliability of thesoftware. So how to improve the reliability of the software is the key to improve thereliability of the whole CNC system. This paper gave the FMECA to a certain type softwareof CNC system. Found out the weak parts, main mode and the major cause of faults. Andproposed effective countermeasures to improve the reliability of the CNC software.From the perspective of failure mechanism, the fault of the CNC software can bedescribed “software-error→software-defect→software-fault”, that is to say, the designersbrought in some defects during the processing of designing, when the execution trace wentthrough a defect, and activated it, the software would be failure. So locating the faultsquickly and accurately when the CNC system becomes failure is the most efficient way toreduce the loss. This paper proposed a new method to locate the fault of CNC software.This method contained tow parts—generating the similar execution traces set based on thedifference of nodes and calculating the suspiciousness of the statements executed by these traces based on the fuzzy algorithm. This could locate the fault of the CNC software into thecode layer. Finally, gave an experiment on the NURBS interpolation for fault location. Theresult showed that this method was very effective in fault location and it provided a newidea for the fault location of CNC software.