Research On Modeling Methods Of Building Hydraulic Components And System Model Library Based On Modelica Language

The main research content of this thesis is the establishment method of hydraulic components and system library based on Modelica language.The purpose of the research is to give a general scheme of hydraulic system modeling and solve the problem of high cost of modeling and simulation in practical engineering.In the process of research,this thesis deconstructs the mathematical model of typical hydraulic components,and obtains a large number of basic models of reusable hydraulic components.The general hydraulic system simulation model library is established by using Modelica language,and the modeling and simulation of typical hydraulic system is successfully realized.This thesis firstly analyzes the current development status of hydraulic system modeling and simulation technology,and in view of the high cost of hydraulic system modeling and simulation in practical engineering,puts forward the method of using Modelica language to model hydraulic components and systems in open source simulation environment Open Modelica.Then,the basic principle of hydraulic system simulation modeling is revealed through the example of the mathematical model derivation process of pump-controlled motor system.The hydraulic schematic diagram is converted into differential algebraic equations(DAEs)and solved by numerical algorithms.The main algorithms for solving DAEs are analyzed and the solution process is explained.Then the principle of modeling and simulating hydraulic systems using Modelica language was discussed,and the basic principle of automatically deriving mathematical models of hydraulic systems in Open Modelica was revealed.The automatic derivation process is as follows: first,write a global equation with non causal characteristics based on the hydraulic system principle diagram,then eliminate duplicate variables,and finally,based on graph theory,convert the simplified global equation into an executable algorithm sequence with causal relationships that is easy to execute by computers.Then the basic models of typical hydraulic components are established by using Modelica language and non-causal modeling in Open Modelica environment,and these basic models are expanded into hydraulic component models with good reusability.Thus,the general scheme of hydraulic system component modeling is given.Based on this,a general hydraulic system simulation model library Hydraulic Lib is developed.Finally,in order to verify the correctness of the developed model base and the feasibility of the proposed method,the correctness of the hydraulic component model is verified by using the unit verification method.The correctness of the hydraulic transmission system and the hydraulic servo system established by the model base is verified by the whole system verification method.