Virtual automatic tool changer of a machining centre with a real-time simulation

Abstract

The discrete systems in a machining centre, such as the automatic tool changer and automatic pallet changer, play important roles in improving productivity in machining automation. However, system configuration and sequential logic programming still require considerable skill and are handled on a case by case basis. A simulation-based verification environment could improve system performance, reduce ramp-up time and cost, and avoid false setup and system deterioration. In this study, we developed a simulation model as well as a visualisation of a disk-type automatic tool changer (ATC) to assist with ATC mechanical design and PLC logic verification. Our simulation model was based on an object-oriented modelling approach, and consisted of model blocks corresponding to essential components such as the motor, gear set, cam-follower, and proximity sensors. We tested the model in a real-time simulation that used the software component of an actual machine tool controller in the simulation loop to evaluate the real-time calculation performance and the feasibility in a real application such as logic and configuration verification. The results related to the feed drive motion with limit sensor action in the ATC turret operation showed that our approach was practical and met the real-time requirements.