Showing papers by "Eugenia Minca published in 2019"

Modelling and Control of Mechatronics Lines Served by Complex Autonomous Systems

Abstract: The aim of this paper is to reverse an assembly line, to be able to perform disassembly, using two complex autonomous systems (CASs). The disassembly is functioning only in case of quality default identified in the final product. The CASs are wheeled mobile robots (WMRs) equipped with robotic manipulators (RMs), working in parallel or collaboratively. The reversible assembly/disassembly mechatronics line (A/DML) assisted by CASs has a specific typology and is modelled by specialized hybrid instruments belonging to the Petri nets class, precisely synchronized hybrid Petri nets (SHPN). The need of this type of models is justified by the necessity of collaboration between the A/DML and CASs, both having characteristics and physical constraints that should be considered and to make all systems compatible. Firstly, the paper proposes the planning and scheduling of tasks necessary in modelling stage as well as in real time control. Secondly, two different approaches are proposed, related to CASs collaboration: a parallel approach with two CASs have simultaneous actions: one is equipped with robotic manipulator, used for manipulation, and the other is used for transporting. This approach is correlated with industrial A/D manufacturing lines where have to transport and handle weights in a wide range of variation. The other is a collaborative approach, A/DML is served by two CASs used for manipulation and transporting, both having simultaneous movements, following their own trajectories. One will assist the disassembly in even, while the other in odd workstations. The added value of this second approach consists in the optimization of a complete disassembly cycle. Thirdly, it is proposed in the paper the real time control of mechatronics line served by CASs working in parallel, based on the SHPN model. The novelty of the control procedure consists in the use of the synchronization signals, in absence of the visual servoing systems, for a precise positioning of the CASs serving the reversible mechatronics line.

Optimal control of the complete assembly/disassembly cycle for a mechatronics line prototype

Abstract: The aim of this paper is to define a control strategy for complete manufacturing cycle of an assembly/disassembly educational mechatronics line (EML), assisted by a complex autonomous system (CAS), a wheeled mobile robot (WMR) equipped with robotic manipulator (RM). By reversibility we mean that the line is able to perform automatic disassembly of the product detected as defect. Disassembly starts after the assembly process and after the assembled piece fails the quality test, in order to recover the parts. The CAS is used only during disassembly, to transport the parts from the disassembling locations to the storage locations. The disassembly workstation, designed and implemented as a prototype structure, functions as an integrated system in the automized control of the SMART Assembly Mechatronic Line (SAML), on which the research was made. For the control of the complete cycle assembly/disassembly mechatronic line, was identified a strategy that will be subordinated to the concepts of energetical optimization and high productivity. For this purpose, the EML served by CAS, having a specific typology, are modelled by specialized hybrid instruments belonging to Petri Nets class: Timed Petri Nets (TPN), Hybrid Petri Nets (SHPN). The results of the simulations highlight the coherence of the control structure and the absence of blockages in the dynamics of the simulated processes: assembly, disassembly, recovery of the components in warehouses. Using these models and the optimization results, a real-time control structure has been designed and implemented, allowing automated assembly and disassembly, assisted by a CAS.

Mechatronics Manufacturing Line with Integrated Autonomous Robots and Visual Servoing Systems

Abstract: This paper deals a manufacturing technology on a processing/reprocessing mechatronics line (P/RML), based on autonomous robots and visual servoing systems (VSSs). The P/RML has four workstations, line shaped, being serviced by two wheeled mobile robots (WMRs), robotic manipulators (RMs) and two types of VSSs for caching, transporting and releasing work piece. Due to the control structure, P/RML becomes fully automated allowing processing, reprocessing, manipulation and transport, without the intervention of the human operator. If the processed piece does not pass the quality test, it is taken from the last stations of the P/RML to be transported to the first station where it will be considered for reprocessing. The P/RML assisted by WMRs, RMs and VSSs, was modeled with the synchronized hybrid Petri nets (SHPN). Trajectory-tracking, sliding-mode control (TTSMC) is used to control WMRs. Two types of VSSs were used for the precise positioning of the RMs when catching or releasing the work piece. To the first one, called eye to hand, the web camera has a fixed position, usually positioned on the last workstation of the P/RML. To the second one, called eye in hand, the web camera is located on the endeffector of the manipulator, thus the VSS is mobile.