In this paper a concept for modeling flexible mechatronical based assembly systems will be described. For the development of such assembly systems, modular mechatronic components are being applied. To test the requirements and behavior of the various components required in an assembly system, a library of these mechatronical components is developed. These components are being programmed using a distributed control approach. The work discussed here is being applied in the FP6 Integrated Project PISA funded by the European Commission.