Modelica Oriented Multi-body Modeling Based On Cartesian Method

Complex electromechanical product is usually composed of elements from a number of domains, traditional single-domain simulation tool cannot meet their demand for system simulation. Modelica, a multi-domain unified modeling language that can describe models of different domains in an uniform way, is very suitable for the modeling and simulation of such kind product. Mechanical multi-body simulation, which is an important part of the simulation of electromechanical product, should be well-supported by Modelica, but the mainstream way for creating Modelica multi-body model, which is using Modelica standard multi-body library or other similar methods, is not efficient. The modeling process of these methods is very complicated and the created model is not intuitive, furthermore, these methods cannot process redundant constraints and initial assembly problem, and not easy to import the models of mainstream multi-body simulation software, such as ADAMS.According to the problem mentioned above, Multi-Body Cartesian Method is used as this paper's theoretical basis and an intuitive and efficient method for creating Modelica multi-body model is put forward. In the method, three-dimensional visual modeling tool is used as modeling front-end and a 3D visual Modelica multi-body modeling software is implemented. Some works have been done for the purposes as follows:1. Multi-Body physical model and mathematical model are discussed in detail, and the solutions to the problems of redundant constraints and initial assembly are present;2. Based on Multi-Body Cartesian Method, the whole mapping process of multi-Body system from physical model to mathematical model and at last to Modelica model is explored, with which automatical convertion from physical topology of constraint-based multi-body system to Modelica mathematical code can be implemented;3. Based on the automatical convertion technology mentioned above, a Modelica multi-body visual modeling system is designed and implemented, which uses InteDyna as its modeling front-end.Finally, the Modelica code outputted by the implemented system is tested in multi-domain unified modeling and simulation platform MWorks, and the result demonstates the effectiveness of the mapping technology and the rationality of the Modelica multi-body visual modeling system. The proposed method laid the foundation for the transformation from assembly model of general mechanical design software to multi-domain functional model.