The Extensible Elementary Composable Simulation Based On Linear Graph Theory

The complicated engineering system will be involved in the multidiscipline fileds, including mechanical, hydraulic, and controlling system, etc., and is intergreted into an organic whole with those subsystems. Then the characteries of such system should be realized with the technologies belonged to every discipline field, i.e., the heaven forging manipulator is a typical mechano-hydraulic coupling system. It is a kernel question to realize modelling with an unified tool for simulating multidiscipline system. However, there are three main disadvantages in the achieved approaches of unified modelling now, and they are follows: it is difficult to express the mechanical multibody system described with vector variables; the moldeling range is limited in a large extent, such as joint clearences, flexible bar, etc. specific mold; some unified methods could not be realized automatically by computer.Therefore, the development and complement of unified modelling method is a beneficial topic for simulating the whole functions of multidisciplinary system. Graph theory is one of the unified modelling methods. Based on the traditional linear graph theory, the paper proposed the Extensible Elementary Linear Graph method (EELG), which could realize composable simulation for multidiscipline system, and perform inter-energy domain expression in a unified way. We focused on the research of modelling rules, encapsulating topology, and standardizing multidisciplinary components, etc. By connecting the modules'port successively, the system linear graph will be obtained by assemblizing modules'elementary linear graphs. Some librarys of standard multidisciplinary components were developed with Modelica lauguage, and then the system equations will be solved on Dymola platform. With EELG method, it can be simulated that the system can include mechanical rigid and flexible dynamics, joint clearences dynamics, mechano-hydraulic coupling analysis, and so on.The main thesis research results and characteristics are as follows:(1) Combining the conventional linear graph theory with the technologies of modularization, encapsulation and object-oriented, we researched the extensible elementary linear graph and composable modeling based on the former. In the EELG framework, the component-level dynamic equations would be automatically generated by matrixes operation of topology matrixes and vector variables. Furthermore, the connection of variables between two components could be created by the relational expressions of linking two ports, and the inter-energy transformation can be realized by coupling components. Then the sate equations of the whole multidisciplinary system could be formed by collecting these terminal equations.(2) By defining the rotation vector in modelling of mechanical members, one can analyze rotational and translational motion in a same elementary linear graph, and then both of the modelling process and fainal results became simpler. For kinematic pairs modularizing, the kinematic function vertices, opening edges and self-closed edges were introduced to the elementary linear graph, and enrich the symbols of the linear graph theory. The various combinations consisted of mechanical members were dealt with as a whole module separativly, instead of being assembled with many basic modules belonged to conventional package.(3) We extended the linear graph theory to the dynamic analysis of kinematic clearances and flexible beams. With firstly introdcing clearance vectors edges and the kinematic function vertices related to clearance, we combined it with the Dubowsky classical models in two state motions, and created the elementary composable model of kinematic clearances. By originally defining the elastic rotational vectors edges, elastic transational vectors edges, we adopted Newton-Euler equations and cubic polynomial fitting curve, and analyzed the elastic component for expressing elementary composable model.(4) With the definition of hydraulic ports, hydraulic function points, and hydraulic vectors edges, we established the elementary encapsulation linear graph of hydraulic members, and elementary topology vectors. We also solved the key issue of mechano-hydraulic coupling in the form of linear graph. Finally, we successfully applied the linear graph theory to mechano-hydraulic systems, which are the association of planar mechanism in rotation, general motion, or translation and hydraulic devices.(5) According to the structure and working, we created the composable model for heaven forging manipulator with EELG method. By simulating the load condition in forging process, the relation of manipulator acting and deformation shock would be obtained. By summarizing theorical analysis and application, it is validated that the proposed approach of the extensible elementary linear graph made some achievements in multidisciplinary composable simulation. And then the modelling range was enlarged, and the simulating efficient was improved. So the effective method and tool were provided for simulating multidisciplinary system.