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Research On Modeling Methodology For Concurrent Design

Posted on:2008-04-25Degree:DoctorType:Dissertation
Country:ChinaCandidate:B W JiFull Text:PDF
GTID:1102360242467668Subject:Mechanical design and theory
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After a systematic analysis of the state-of-the-art of research on concurrent and cooperative design, a design methodology for complex products like excavator is originally put forward for computer-aided design of technical artifacts, aiming at solving some crucial issues in this research area such as process modeling, design supporting and CAD/CAE integrated modeling, control planning etc. The primary contributions are as follows.First, according to the design requirement of the concurrent engineering, the solution method was proposed based on the products' information growth and the model's dynamic regeneration. The knowledge frame of dynamic solution was built, and three key problems were mentioned: knowledge expression, flexible modeling system and the spiral design progress for the following research.Secondly, research on flexible modeling strategy for dynamic solution. The theory of products' general and limited design potential model was proposed, based on the traditional logic and potential model theories and combined with the information expanding process of the complex products' parameters, objects and constraints. The traditional functions were reconstructed using the complex functions' multistage decomposition and confidence sequencing methods. The single product information model was extended to a process model with design guide and reasoning performance based on sensitivity analysis, in order to set the foundation of this theory's application. The application example of excavator design indicates that the reconstructed design supporting model is flexible and suitable for the concurrent design requirements.Thirdly, research on flexible design support model based on potential model theory. The multiple knowledge models were defined with expression and reasoning mode for the complex product design's dynamic and incomplete information reasoning requirements, which has the potential, flexible and design-guiding characteristics. The design supporting models for the expanded design process were reorganized based on above model. The design direction was recommended by the design guiding, to improve the efficiency of problem solving in addition. This method can ensure the consistency and continuity of design knowledge used in different phase models and expands the model with design information's expanding. Finally the example of excavator design was used to show the modeling method and application.Fourthly, research on spiral design process model of complex products like excavator. The improved spiral process model and potential model were proposed to the concurrent design engineering, to make up the disadvantages of the traditional design process, including the immovable design phases, redundancies of knowledge resource and absent dynamic adjustments. The stepwise process style and product model can improve the efficiency of modeling and solving, which is required by the life-cycle product's design. In addition, the design risk can be examined by the expanded constraint network, based on the potential model theory. The modification method of using current information to correct the forgoing design model was imported in the design feedback, to deduce the conflict according to the model predigestion and design supposion. In the end the example of excavator design was shown to prove this method.Fifthly, research on integrated modeling technology of CAD and CAE. The detached status between CAD and CAE technology was analyzed. The CAD parameterized modeling method can resolve the modeling and optimizing problem of the current CAE software. The virtual prototype CAD and CAE integration modeling research was made, based on the parameterized design method for general optimization, the entireness modeling and assembling technology, and the ADAMS and PRO/E united modeling technology. In the end the excavator's work device parameterized model and the virtual excavator prototype was built to validate this method. It improves the relevancy between CAD and CAE, and the conclusion of CAE can respond to the design flow immediately. So the design cycle is reduced and the quality of the product is improved.Sixthly, research on excavator's path planning based on optimization method. In order to obtain an accurate trajectory with manipulating stability and energy saving, an intelligent trajectory planning method is proposed. An optimizing model was built with the variables of excavating angles, the targets of hydraulic cylinder's moving and acceleration grads, and the restrictions of condition blind angle and best cutting angle range. The genetic algorithm was adopted. The analyzing results of different planning methods are given in the end, which shows that the optimizing planning method can reduce the hydraulic system's impulsion and oscillation, and improve the maculating stability effectively.Finally, research on concurrent design platform of hydraulic excavator. The integrated platform was built with CAD&CAE modules and control planning module. Additionally the flexible design supporting model based on multiple knowledge models was built to satisfy the excavator's spiral design process.
Keywords/Search Tags:Concurrent Design, Modeling, Potential model, multiple knowledge model, Dynamic solving, Spiral model, Design feedback, Model modification, Excavator, Path planning
PDF Full Text Request
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