基于Petri网的MEMS柔性设计建模方法

微机电系统设计具有微尺度效应和多物理场耦合的特点,而现有的面向产品宏观结构的CAD系统难以满足微米尺度设计需求,为此提出一种基于Petri网的MEMS柔性设计建模方法.在分析MEMS设计特点、框架和流程的基础上,对已有设计系统进行抽象化和精细化,获得高内聚低耦合的设计模块,并将Petri网与设计系统各模块相互关联,建立了基于Petri网的MEMS柔性设计建模框架;然后通过添加前置库所和带权有向弧调节库所最大/最小标识数,控制设计流的总数;再添加控制库所形成控制回路,使并发变迁有序执行,消解并行设计冲突;最后用Petri网的状态空间求解结果控制各模块运行,满足复杂设计流的多元关系.以ACIS为几何造型内核开发了自主原型系统,以电容式三维硅微梳齿驱动器设计为例进行应用验证,结果表明,文中方法将现有MEMS设计从自顶向下和自底向上及其混合拓展到基于Petri网的柔性设计建模,使产品设计不局限于固定的设计流程,对于提高MEMS设计效率和质量具有重要意义.

Flexible Design Modeling Methodology for MEMS Based on Petri Net

Micro-scale effect and multi-field coupling are characteristics of the design of micro-electro-mechanical system (MEMS). However, the current macroscopic structure-oriented CAD systems have not been able to meet the increasing requirements for the design in micrometer scale. Therefore, a flexible design modeling methodology for MEMS based on Petri net is put forward. Firstly, the highly cohesive and low coupling modules are obtained via refining and abstracting the existing CAD systems on the basis of analyzing the design characteristics, framework and process of MEMS. Secondly, the flexible design modeling framework for MEMS based on Petri net is built by associating the Petri net with the modules of the design system. Then, the forward-position places and weighted directed arcs are added to regulate the maximum and minimum tokens of the places to control the number of design flow. Afterwards, the control places are added to format control loops and make concurrent transitions occur orderly to solve the conflicts in concurrent design. Finally, the modules are controlled to operate with the state space results of Petri net. The multiple relationships between the complex design flows are then realized. An independent prototype system using ACIS as geometry modeling kernel has been developed to validate the proposed method with the design of capacitive 3D silicon micro comb drive. The test results proved that the present design methods are extended from top-down, bottom-up and hybrid to flexible design based on Petri net. The product design is no longer restricted to fixed process. It has important significance to improve efficiency and quality of the design of MEMS.