Machines degrade as a result of aging and wear, which decreases performance reliability and increases the potential for faults and failures. The impact of machine faults and failures on factory productivity is an important concern for manufacturing industries. Economic impacts relating to machine availability and reliability, as well as corrective (reactive) maintenance costs, have prompted facilities and factories to improve their maintenance techniques and operations to monitor machine degradation and detect faults. This paper presents an innovative methodology that can change maintenance practice from that of reacting to breakdowns, to one of preventing breakdowns, thereby reducing maintenance costs and improving productivity. To analyze the machine behavior quantitatively, a pattern discrimination model (PDM) based on a cerebellar model articulation controller (CMAC) neural network was developed. A stepping motor and a PUMA 560 robot were used to study the feasibility of the developed technique. Experimental results have shown that the developed technique can analyze machine degradation quantitatively. This methodology could help operators set up machines for a given criterion, determine whether the machine is running correctly, and predict problems before they occur. As a result, maintenance hours could be used more effectively and productively.
