Control of reconfigurable assembly system

[摘要] ENGLISH ABSTRACT: This work considers the control of reconfigurable assembly systems using a weldingassembly system as a case study. The assembly system consists of a pallet magazine, afeeding system, an inspection and removal system, a welding system and a conveyor. Theaim of the work is to compare PC and PLC as controllers, as well as to compare twodifferent approaches to reconfigurable control.The control system of the pallet magazine was developed using a PC and a PLC. The PCcontrol was programmed using Visual C#, while the PLC was programmed in Ladder Logicusing Siemens S-300 STEP7. The two controllers were compared based on the attributesthat measure the quality of a controller's software, which include its capability,availability, usability and adaptability.The approaches to reconfigurable control considered were the agent-basedmethodology and the IEC 61499 distributed control methodology, both of which wereapplied to the feeding system. The agent-based control system was implemented usingthe JADE agent platform, while the IEC 61499 distributed control system wasimplemented using the FBDK software kit. These two methods were compared based onthe characteristics of a reconfigurable system, which include the system's modularity,integrability, convertibility, diagnosability, customization and scalability.The result obtained in comparing the PC to the PLC shows that the PLC performs betterin terms of capability, availability and usability, while the PC performs better in terms ofadaptability. Also, the result of the comparison between the agent-based control systemand the IEC 61499 distributed control system shows that the agent-based control systemperforms better in terms of integrability, diagnosability and scalability, while the IEC61499 distributed control system performs better in terms of modularity andcustomization. They are, however, on a par in terms of convertibility.

[发布机构] Stellenbosch University