Holonic Assembly System
(Prof.
T. ARAI and Y. MAEDA)
In recent years, manufacturing systems must have much flexibility (fault-tolerance, versatility, agility, etc.) to cope with dynamic changes of their environment. We have proposed a flexible assembly system with the concept of holon, as a distributed autonomous manufacturing system.
Holons are autonomous and cooperative components of the system. They form a “holarchy” (hierarchical control architecture) to execute tasks. The holarchy of the system consists of management holons and execution holons (Fig. 1). If a management holon is ordered to assemble a product, this assembly task is decomposed into subtasks for lower management holons. A terminal management holon (operation holon) secures appropriate execution holons, which correspond to manufacturing devices using the contract net protocol, and makes them execute a simple job, such as assembling parts. We implemented a real holonic assembly cell shown in Fig. 2. The decentralized nature of the system enables us to realize “Plug & Produce,” a system function that supports easy addition/removal of manufacturing devices. We are developing some techniques for Plug & Produce, such as a distributed resource allocation method for installation of new robots (Fig. 3), and an automated calibration for mutual positional relationship between an existing robot and a newly added one (Fig. 4).
Keywords: Holon, Holarchy, Assembly, Manufacturing Systems, Plug & Produce
References
Tamio Arai, Yasumichi Aiyama, Masao Sugi, Jun Ota: “Holonic assembly system with Plug and Produce,” Computers in Industry, Vol. 46, No. 3, pp. 289~299, 2001.
Masao SUGI, Yusuke MAEDA, Yasumichi AIYAMA and Tamio ARAI: “Holonic Robot System: A Flexible Assembly System with High Reconfigurability,” Proc. of 2001 IEEE Int. Conf. on Robotics and Automation, pp. 799-805, 2001.
T. Arai, Y. Maeda, H. Kikuchi, M. Sugi: “Automated Calibration of Robot Coordinates for Reconfigurable Assembly Systems, Annals of the CIRP, Vol. 51, No. 1, 2002 (to appear).
Fig. 1 Holarchy for Holonic
Assembly Cell
Fig. 2 Holonic Assembly
Cell
Fig. 3 Plug-in of a New
Device
Fig. 4 Automated
Calibration System for Plug & Produce