Study On Optimization Design Method For Mechanical-Electrical-hydraulic Integrated System Based On Collaborative Simulation

Mechanical-electrical-hydraulic integrated system is a high technology density and complex interdisciplinary system. Usually it is composed of several subsystems, such as mechanical subsystem, hydraulic subsystem, control subsystem. There is a coupling relationship among subsystems that they have mutual influence and interaction. Mechanical-electrical-hydraulic integrated system covers multidisciplinary content, not only including the traditional structural mechanics, fluid mechanics, control theory and so on, but also including modern ergonomics, etc. For designing the mechanical-electrical-hydraulic integrated system by using the traditional design method and sequence design method, mutual influence and coupling effect among the subsystems or subjects are ignored, which often makes the results of the design not the most optimal solution, and the efficiency of the design is low, the cycle is long, the cost of design is high. The design of mechanical-electrical-hydraulic integrated system has the obvious multidisciplinary characteristics, which belongs to the typical multidisciplinary design problem. With the constant improvement of structure mechanics, fluid mechanics, and control discipline theory, and the rapid development of computer technology, people can use a higher precise model to analyze and design subsystem or subject, and design of subsystem or subject has made great progress. Therefore, how to comprehensively coordinate each subsystem to make multidisciplinary design becomes the bottleneck problem of the mechanical-electrical-hydraulic integrated system design.Multidisciplinary design optimization method integrates different subject knowledge, analysis and modeling theory and calculation method in the design process of whole complex system, to get the optimal solution of the whole system by applying effective design optimization strategy and making full use of the synergistic effect which the interaction between subjects produces. Multidisciplinary design optimization is a design method that fully utilizes and considers interaction and coupling effect between disciplines, and use multidisciplinary method to achieve optimal comprehensive performance. The basic ideology of multidisciplinary design optimization technique is to organize and manage optimization design process by using appropriate optimization strategy, and through the decomposition and coordination, to decompose complex system into several subsystems that are consistent with engineering design organization form. Thus by using the existing industry disciplinary analysis and design tools to comprehensively design complex system by integrating rich knowledge and experience of interdisciplinary or subsystem in the distributed computer network, so as to achieve the purpose of shorting the design cycle, reduce development cost and enhance the competitiveness of their products.Because the multidisciplinary optimization problem often has the following characteristics:big amount and complex type of design variables and the constraint condition, and mutual coupling relation among parts and sub-blocks, consequently it is difficult to establish the optimization model and to find effective optimization algorithm. Two kinds of coupling factors:one is the variable to be optimized in the many field design, namely system variables or cross variable; the other is the variable which is a calculation parameter of a field as an input of another field, namely relevant variables or coupled variables. The design of mechanical-electrical-hydraulic integrated system involves mechanics, hydraulics and control disciplines, including optimization of parameters of overall plan and structure, the comprehensive optimization of mechanical properties. When it comes to the problem of designing the overall situation and the whole process, there are still many difficult problems to solve. Whether the optimization of the mechanical-electrical-hydraulic integrated system can be well solved, mainly depends on two factors. One is to establish the reasonable optimization model, and another is to choose effective optimization algorithm which is suitable for this model.Therefore, in this dissertation, the multidisciplinary design optimization method which develops rapidly in the aviation field and can solve complex system design and optimization problem, is introduced to comprehensively study the optimization design method of mechanical-electrical-hydraulic integrated system. To explore multidisciplinary optimization method feasibility and applicability in the application of mechanical-electrical-hydraulic integrated system design. The dissertation covers the design optimization model and optimization algorithm of mechanical-electrical-hydraulic integrated system, optimization modeling and simplification, optimization strategy, combinative simulation research, development of integrated optimization platform, parallel robot system optimization, etc. The main work of the paper includes the following several aspects:1. Mechanical-electrical-hydraulic integrated system design optimization modeling and simplificationAccording to the characteristics of mechanical-electrical-hydraulic integrated system overall design, mechanical-electrical-hydraulic integrated system will be divided into three independent subsystem, namely mechanical, hydraulic and control subsystem. On the basis of system analysis, the subsystem mathematical analysis model is established, the design parameters are extracted, and the input and output parameters of subsystem and the coupling relationships among them are established. The optimization model of mechanical-electrical-hydraulic integrated system is established. The approximation model techniques of multidisciplinary design optimization are studied, the quadratic response surface and kriging approximate model are applied to the optimization of the mechanical-electrical-hydraulic integrated system. The research indicates that in the optimization design of mechanical-electrical-hydraulic integrated system, the complex, high-precision module is replaced by the approximation model to optimize and iteratively calculate, which greatly reduce the computing amount and improve the efficiency of optimization computation, so the computing bottleneck problems of the mechanical-electrical-hydraulic integrated system optimization are solved, and it has strong engineering practicability.2. Optimization strategies and algorithms research of optimization model for mechanical-electrical-hydraulic integrated systemBy analyzing the existing optimization method and algorithm, mechanical-electrical-hydraulic integrated system model is optimized and analyzed by using different optimization methods, optimization algorithms and united algorithms. The research shows that by using traditional numerical optimization algorithms, optimization time is short and it is suitable for the unimodal problem; intelligent optimization algorithm has better optimal performance and long optimal time, and it is fit for multimodal problem. So the combinational algorithms strategy, including global exploration and local optimization, is chosen to optimize the mechanical-electrical-hydraulic integrated system problem. The multi-island genetic algorithm is used to search and determine the optimal value range, and traditional local algorithm is used to achieve optimal value. The result shows that combinational algorithm strategy has the advantage of fast and efficience, high accuracy, and global optimal values.3. Development of integrated optimization platform for mechanical-electrical-hydraulic integrated system based on the co-simulationIntegrated theory and implement method of simulation and optimization for mechanical-electrical-hydraulic integrated system are put forward. The interface among software ADAMS、ANSYS、MATLAB and CATIA is study to integrate the CATIA, ADAMS and MATLAB software into software ISIGHT software platform. The CATIA software of virtual modeling function, ADAMS and MATLAB software dynamics simulation and control simulation function and ISIGHT software integrated optimization function are effectively used to set up the simulation optimization platform for mechanical-electrical-hydraulic integrated system and realize integrated optimization of mechanical-electrical-hydraulic integrated system based on co-simulation. By verifying example, the results show that by using the integrated optimization platform, the platform is feasible and the optimal results are reliable.4. Simulation and optimization of6-DOF Parallel robot systemCombinative simulation and integrated optimization of the parallel robot system are studied by using the established simulation platform. Through simulation and optimization, the validity of the approximation model and the algorithm for mechanical-electrical-hydraulic integrated system is verified, the computing time of optimization model for the system is greatly reduced and the design efficiency is improved.