Lego Factory: An Educational Cim Environment For Assembly

This paper describes a general concept for a computer integrated manufacturing (CIM) environment intended for the design and assembly of “products” built out of Lego blocks. These “products” are conceptualized and designed within a Lego CAD System from a small set of the most commonly used Lego building blocks. Process planning and trajectory planning software is used to determine the build sequence and robot program for assembling the model directly from the 3D CAD model. The robot program is fed into a cell controller to perform the physical build of the “product”. This paper also describes student projects designed to explore the feasibility of the technical concepts necessary for such a system. These include a robot gripper, a block sorting mechanism, and an assembly planning system integrated with the Lego CAD system and the physical assembly cell. INTRODUCTION AND MOTIVATION Computer Integrated Manufacturing (CIM) is typically defined as the use of Computer and Automation Systems to operate and control production. This definition breaks the production activities into two major categories: the information processing performed by Computer-Aided Design and Planning systems and the physical activities performed by automation systems. Information processing tasks include: the design of components; planning the production of the components; controlling the operations in production and performing various business related functions necessary for running a manufacturing enterprise. The physical activities are performed by a wide range of devices, often automatically controlled, including machine tools, assembly stations, robots, material handling and storage systems and quality inspection systems. These devices perform material transformations according to predefined process steps, move about a factory, take measurements, and ultimately feed back information to the human operators. They automate the physical activities. In the same way that the devices on the shop floor automate the physical activities, the CAx (x = Design, Process Planning etc.) systems automate the information processing functions assuming that these different functions are closely integrated. To achieve CIM, all aspects of the manufacturing enterprise must be integrated so that they can share the same information, communicate with one another and provide a global picture as to the state of the entire manufacturing facility at any time. P ge 10887.1 Proceedings of the 2005 American Society for Engineering Education Annual Conference & Exposition Copyright © 2005, American Society for Engineering Education The primary challenges for academic institutions which wish to offer CIM courses are: (1) the cost of the appropriate equipment, and (2) the relative complexity of a functional and meaningful CIM environment. It is clear that creating educational systems that emulate the complexity of industrial systems for studying CIM concepts for assembly in particular is not a trivial task. This paper describes a general CIM system concept which can be used to design and fabricate products built from Lego blocks. Such products are conceptualized and designed within a Lego CAD System from a subset of the available Lego building blocks. Assembly sequences for building these products are carried out by means of robotic devices. Process planning and trajectory planning software are used to determine the build sequence and programming the robots for assembling the model directly from the 3D CAD model. The robot program is fed into a cell controller to perform the physical build of the “product”. The overall sequence of activities carried out by the system is shown in Fig. 1. Figure 1 Lego production system activities The long-term goal of this effort is to develop and implement such a concept by utilizing the assembly capabilities of Lego blocks. Lego blocks have the combined advantage of providing a richly diverse part family from an assembly perspective while at the same time simplifying fixturing and gripping issues through use of the blocks patented fastening mechanism. EXISTING APPLICATIONS Lego is a building system based on modular blocks (also called bricks), equipped with a functional binding mechanism. Two Lego parts can be connected to one another in a number of different ways and stay that way until they are separated. While the original Lego block concept was purely mechanical, most recent offerings also include embedded computational and sensing capabilities. LEGO CAD LEGO Production System Assembly Process Planning