The Hydraulic Simulation Software Zjusim Of Development And Parameter Optimization Study

Simulation Technology plays an important role in the design, analysis, and amelioration of hydraulic systems. Its significance has been widely recognized in relevant engineering fields. In order to make the hydraulic simulation technique accessible to most engineers, it is necessary to develop an appropriate hydraulic simulation software package that can obtain the dynamic characteristics of the target hydraulic system. Since MS Windows series have become the mainstream platforms of application software with friendly Graphic User Interface, it is a tendency to provide the Windows version of engineering application software.This thesis is based on the work of researching and developing the hydraulic simulation software ZJUSIM on the platform of Windows 2000, aiming at a software package that can be used to design hydraulic systems rapidly and accurately with desired system parameters. The research work of this thesis involves following aspects: modeling and simulation, user interactive interface, database and parameters optimization.The method of transfer function analysis in classical control used to be the main stream for researching the dynamic features of hydraulic system. Nowadays, with the advancing technology of computer hardware and maturation of modern control theory, bond graph and finite volume become the two main methods of researching. Considering the technique accumulation on finite volume research in the State Key Lab of Fluid Power Transmission & Control, modeling of ZJUSIM uses the approach of finite volume. As the core of ZJUSIM, simulation module uses following technique routine: 1.Drawing the draft of hydraulic system;2. Creating system model description file;3. Creating files of system component parameters and simulation parameters;4.Setting component parameters and simulation parameters; 5. Creating Fortran codes of the differential equations representing hydraulic system; 6. Compling and linking the Fortran codes, executing the linked program and display the result.Combined with the technology of Object Orient and Windows' GUI, ZJUSIM provides operations upon screen drafts and direct edits to background model files and parameter files. One order predicate is introduced into this thesis with a logic server written in Prolog so that any component' s symbol is dynamically associated with its type, parameter list, and units of parameters. It is a convenient way to modify and update the component library. According to the noncontinuity of differential equations of hydraulic system and the complexity of objective constraint function, this thesis uses Genetic Algorithm as the optimization algorithm. Optimization efficiency can be maximally enhanced by using strategies of floating point numbers coding, choosing appropriate mutation and cross-over, numbers of generation and population, keeping mutants with high fitness, and opening a virtual disk in memory space for frequent file reading, writing, complying, and linking during the optimization.ZJUSIM can be widely applied in simulation and design of varied hydraulic systems, and it can be also used for reference for developing pneumatic simulation software. Through simulation and optimization of example systems, ZJUSIM is testified to be practical and efficient.