基于模糊PD控制的微操作机械手真空微夹研究

Study of the vacuum micro-tool for micromanipulator based on fuzzy PD control

由于重力和粘附力的变化,宏观工具不再适用于对微粒的操作.采用真空方式对微粒进行操作是一种较为理想的策略.设计了一种用于微粒(直径100～300μm)装配的真空微夹工具.设计了微夹的一种以ADuc812为底层控制器和以PC机为顶层控制器的两级控制结构.对微粒的粘附力影响和受力情况进行了分析,推导了微夹不同作业阶段的工作压力条件.考虑空气的可压缩性、气动元件的非线性和微夹的压力损失,为提高微夹的拾取和释放微粒的能力,设计了基于模糊PD的压力控制器.Matlab仿真试验结果表明该控制器的有效性.微夹具有性能稳定可靠、结构紧凑的优点,能较好地适用于面向亚毫米级微粒的装配作业.

Because of the different the scaling of gravity and adhesion, the macroscopic applications mechanical grippers could be no more suitable in micromanipulation. A better strategy of handling micro objects is to use vacuum. This paper presented a vacuum micro-tool (integrated into a micromanipulator) for micro objects (with a diameter of 100～300?μm) assembly tasks. A pressure test system based on ADuc812 was designed and a high performance pneumatic valve based on proportional servo technique was adopted as a pressure adjuster. ADuc812, as the lower layer controller, and a PC, as the upper layer controller, compose the tool′s two-layered control architecture. The working pressure of the tool in three phases of pick, hold and place was derived. In view of the high compressibility of air, the non-linearity of the pneumatic components and the pressure losses of the tool, a pressure controller based on fuzzy logic was designed in order to improve its pick and place capability. With MATLAB′s Fuzzy Logic Toolbox, the simulation experiments were performed to validate the performance of the fuzzy PD controller. The tool is characterized by a steady and reliable performance and a simple structure, and it is suitable for handling micro objects with a sub-millimeter size.