Development of multi-functional minute ER device with liquid ciystal and suspension type ER fluid

为了研制多功能微小电流变装置，我们进行了以下两方面的研究：第一，为了在不增加诸如测压元件之类的附加装置的情况下获得用于装置的流动或运动控制的参考数据，我们尝试将液晶电流变装置修改为具有流量传感功能。利用图像分析方法研究了液晶在带条形电极和偏振片的电流变通道中的流动。我们已经发现，通过分析电场下条纹图案产生的亮度轮廓的变化所获得的一些参数对于评估流速是有用的。例如，通过亮度曲线的数字傅立叶变换分析获得的参数、亮度的幅度或平均值与剪切速率（流速）具有良好的关系。对悬浮型电流变液的电流变转换通道进行了测试，在微小的器件中也能获得足够的电流变效应。此外，一个电流变通道的液晶 * 耦合与悬浮类型，以获得电流变，是有用的，为一个宽的流速范围。阐明了悬浮型电流变液的电流变效应在反向通道中得到改善，高电流变效应是由于在电极上产生颗粒层而引起的。通过将液晶电流变通道与悬浮液电流变通道耦合，得到了阀效应和改善的高剪切速率电流变效应。

Following two points have been investigated for the development of multi-functional minute ER device.First, in order to obtain a referential data for the flow or motion control of the device without an extra device such as a load-cell, we have tried to modify an ER device of liquid crystal to have a sensing function of the flow rate. Image analysis is applied to the flow of liquid crystal in an ER channels with stripe-patterned electrode and polarizers. We have found some parameters obtained with the analysis of change in brightness profile generated with the stripe pattern under electric fields are useful to evaluate flow rate. For example, a parameter obtained with digital Fourier transfer analysis of the brightness profile, amplitude or average in brightness have good relationships with shear rate (flow rate). The evaluation error is about 3% and we conclude this method is useful for the practical applications.Second, an ER conversing channel for a suspension type ER fluid has been tested to obtain enough ER effect even in a minute device. Moreover, an ER channel of liquid crystal was*coupled with that of suspension type to obtain an ER that is useful for a wide flow rate range. We have clarify that ER effect ofa suspension type ER fluid is improved in a conversing channel and the high ER effect is caused with a particle layers generated on the electrodes. We also obtained both a valve effect and improved high shear rate ER effect are obtained by a coupling of liquid crystal ER channel with that of suspension type.