Study on Micro Flow Behavior and Applications to Micro Systems of Electrorheological Fluids

电流变液是一类令人兴奋的功能流体，当施加电场时，这种流体在几毫秒内就会显示出戏剧性和可逆流变学变化。因此，例如，在电流变液液压回路系统中，可以使用仅由电极组成的电流变阀来控制压力和流量，而不需要移动部件。本研究针对电流变机械元件如离合器、制动器、减振器和阀门仅用电极就可实现小型化的特点，开展了以下研究工作：(1)将电流变微系统中常用的流场分为压力流、剪切流和挤压流三种流动模式。通过…的流动可视化观察，研究了三种电流变液在微间隙为0.1-0.3 mm的三种流动模式下的微观流动特性给出了适合于电流变微系统的电流变液及其优化设计思想。(2)以微系统为例，采用光刻法制备了由两个电流变阀和一个膜片驱动部分组成的三孔微电流变阀和微执行器。研究了三通微流变阀的流量控制特性和微致动器在开环控制和位置反馈控制下的膜片响应特性。(3)研制了一种以PVDF压电薄膜膜片为驱动元件的电流变液压电微泵。推导了评价圆形单晶片压电膜片性能的归一化方法，分析了膜片变形对输入电压和泵送流量的影响，并实际制作了直径为10 mm的压电膜片泵，对其泵送性能进行了评价。较少

ER fluids are one of an exciting family of functional fluids, which show dramatic and reversible rheplogical changes in several milliseconds when the electric field is applied. Therefore, for example, in the ER fluid hydraulic circuit systems, it is possible to control the pressure and flow rate using an ER valve consisting of only electrodes with no moving parts. In this research, featuring the possibility of miniaturization of ER mechanical elements such as clutch, brake, damper and valve due to their construction using only electrodes, the following investigations have been done in order to develop micro systems utilizing electrorheological fluids as working oils.(1) The flow fields frequently used in the ER micro systems are classified into three flow modes such as a pressure flow, a shear flow and a squeeze flow. For three kinds of ER fluids, the micro flow characteristic in these three flow modes with an about 0.1-0.3mm micro gap was clarified by flow visualization observation in … More close relation to each ER characteristic, and the ER fluid suitable for the ER micro system and the optimal design concept for applications were shown.(2) As some examples of micro systems, the 3-ports micro ER valve and the micro-actuator consisting of two ER valves and a diaphragm drive part were fabricated by the photolithography method. The flow rate control characteristics for the 3-ports micro ER valve and the diaphragm response characteristics for the micro-actuator in open loop control and PID position feedback control were evaluated.(3) A piezoelectric micro pump for ER fluids actuated by a piece of PVDF piezdelectric-film diaphragm for supplying ER fluid to the above micro-actuator was developed. A normalized method for evaluating the behaviors of a circular unimorph piezoelectric diaphragm was deduced and the diaphragm deformation for the input voltage and the pumping flow rate were analyzed, and the piezoelectric diaphragm pump of 10mm diameter was actually constructed, and the pumping performance was evaluated. Less