Control of a flexible finger using electro-conjugate fluid

An electro-conjugate fluid (ECF) is a kind of functional fluid, which produces a powerful flow when subjected to high DC voltage. It is known that a strong ECF flow is generated under non-uniform electric field, for example, the field with a pair of needle and ring electrodes. The ECF flow could be used as a micro fluid pressure source (an ECF pump) for actuators including an artificial muscle and a flexible finger etc. However, previous studies on ECF soft actuators only focused on confirmation of the driving principle. This means, an improvement of performance of ECF pumps and a control scheme for ECF soft actuators have yet to be studied in detail. Hence, this study improves the performance of the ECF pump, and proposes a novel control system for an ECF flexible finger. The ECF pump developed in this study generates maximum pressure of 92.6 kPa and maximum flow rate of 103.0 ml/min with 200.3 mm³. The flexible finger (φ5 mm × 30 mm), driven by the ECF pump, bends 150 deg with a rise time of 1000 ms. In addition, we construct a master-slave system using the ECF flexible finger and confirm its performance.