PWM controlled Micro ER Valve and Its Application to Micro Actuator Control

电流变流体是一类功能流体，在施加电场的几毫秒内表现出剧烈的可逆流变变化。因此，在电流变液液压回路系统中，使用仅由电极组成的无运动部件的电流变阀来控制压力和流量是不可能的。在本研究中，由于ER阀作为开关阀工作，提出了对ER阀进行PWM控制，并且为了开发具有ER阀小型化特点的PWM控制的微型ER阀驱动微执行器系统，进行了以下研究。(1)的流量控制特性和微流模式基本ER阀门组成的两个玻璃电极的间隙范围从0.8到0.1毫米下研究了直流电动控制和PWM控制和缺口大小的影响,应用直流电场强度、PWM波的载波频率和压力均 ... 更多的机会在ER阀门流量控制特性和微观流动模式进行了分析。(2)对于由两个玻璃电极组成的二维矩形通道内电流变流体的振荡流动。用显微镜观察了微观结构的流动模式，并根据确定的流体应变与压差之间的关系评估了ER流体的粘弹性特性。阐明了流体应变幅值、振荡流频率和外加电场强度的影响。(3)在上述研究结果的基础上，研制了一种由一对微型电磁阀驱动的三端口电磁阀驱动的微型波纹管执行器，并对一对PWM控制的电磁阀进行了几种同步控制策略的尝试，确定了一种合适的同步控制策略。然后，将带P11补偿器的位置反馈控制策略应用于所研制的微型作动器，该策略将电流变换器的PWM波占空比与PID补偿器的输出信号成比例变化，并对其控制性能进行研究，以构建基于电流变换器的高精度微伺服系统。少

ER fluids are one of a family of functional fluids, which show dramatic and reversible rheological changes in several millisecond when the electric field is applied. Therefore, in the ER fluid hydraulic circuit systems, it impossible to control the pressure and flow rate using an ER valve consisting of only electrodes with no moving parts. In this research, the PWM control of the ER valve has been proposed because the ER valve works as an ON-OFF valve, and in order to develop a micro-actuator system driven by PWM controlled micro-ER valves featuring the miniaturization of the ER valve, the following investigations have been done.(1) The flow rate control characteristics and micro flow patterns of fundamental ER valves consisting of two glass electrodes whose gap ranges from 0.8 to 0.1 mm have been investigated under DC electric control and PWM control, and the effects of the gap size, the applied DC electric field strength, the carrier frequency of the PWM wave and the pressure differe … More nce across the ER valves on the flow rate control characteristics and micro flow patterns have been clarified.(2) For the oscillatory flow of an ER fluid within a two-dimensional rectangular channel consisting of two glass electrodes. the micro-structural flow patterns have been observed using a microscope, relating to the viscoelastic properties of the ER fluid evaluated from the relationship between a defined fluid strain and the pressure difference. The effects of the fluid strain amplitude and frequency of the oscillatory flow and applied electric field strength have been clarified.(3) On the basis of the above results, a miniature bellows actuator driven by three ports ER valve having a pair of micro ER valves has been developed, The several synchronized control strategies of a pair of PWM controlled ER valves have been tried to determine the suitable one. And then, a position feedback control strategy with P11)compensator in which the duty ratio of PWM wave for the ER valves was varied in proportion to the output -signal of the PID compensator was applied to the developed miniature actuator, and the control performance was investigated to construct a high precision micro servo-system using the ER fluid. Less