Abstract: Estimation and analysis of energy consumption for machine tool is the basis of energy efficiency improvement. The existing researches of energy model focus on the static modelling of energy consumption, and a few study of dynamic energy consumption model focus on the dynamic characteristics of operating states of machine tool, the study of dynamic characteristics of energy sources, especially multi energy sources of a CNC machine tool is scarce. Based on the characteristics of CNC machine tool (e.g. multi-energy sources, dynamically changed machining tasks and process parameters), a method for modeling the dynamic energy characteristics of multi-energy sources in CNC machine tool is proposed. The dynamic characteristics of energy consumption process of machine tool are analyzed. On this basis, the colored timed object-oriented Petri net (CTOPN) integrated with virtual component method is applied to model the dynamic energy consumption of machine tool. The CTOPN model is used to describe the dynamic characteristics of operating states of machine tool and multi-energy sources. The virtual component method is used to describe the dynamic characteristics of multi energy sources which is influenced by process parameters. The virtual component model is driven by the information of activity transitions in CTOPN model. The case study shows that the proposed energy model is effective and can provide fundamental support for dynamic energy consumption forecasting, comprehensive depiction of the energy profile and quantitative analysis of influencing factors and so on during the operation of a CNC machine tool, which has significance in practice.

Key words: CNC machine tool, dynamic energy consumption, modeling and simulation, multi-energy sources