Hybrid systems for planning and optimization of virtual assembly

Abstract

Virtual assembly is the simulation of parts assembly processes by computer, analysing, evaluating and optimizing the feasibilities and procedures of assembly. It can thus avoid the potential problems and risks from designing to assembling. In this way, we can achieve the global optimization of the products and timely respond to the needs of the market. This paper presents a modelling framework for virtual assembly paths design and optimization of two objects on the basis of a class of hybrid system, which is applicable in many manufacturing environments. We propose an elementary hybrid machine containing time-driven and event-driven dynamics. We describe in detail a method of assembly paths design. The objective of optimization is evaluated in terms of time in the transition dynamics so as to make the problem more tractable. An explicit algorithm for deriving optimal assembly policies is developed. The optimal results indicate the feasibility and efficacy of the model and control algorithms.

Keywords:

• Hybrid systems
• Virtual assembly
• Modelling
• Optimization
• Manufacturing

Acknowledgements

This work was supported by the Project of Digital Factory: System Planning Design Oriented towards Complex Manufacturing System and Modelling Method in Production Process Organisation (Sino-German government co-operation project) 2002DFG00027. The authors wish to thank Professor Lin Fen in Wayne State University who supplied lots of valuable documents on hybrid systems and manufacturing.