Development and analysis of an ERF pressure control valve

A new method has been devised for obtaining an arbitrary pressure for driving an artificial muscle by controlling the electric field intensity applied to the electro-rheological fluid. The characteristic of this method lies in the fact that the necessary pressure is generated at the intermediate pressure port by changing the pressure drops based on shear stress changes in the upper and lower pipes. The relationships among the pressure drops, the flow rate and the shear stress changes, and the equations expressing the pressure response to the electric field application, were theoretically derived and compared with the experimental results. Applications of an electric field of pulse-type (digital) variation as well as linear (analog) control showed that both methods generate the necessary pressure. It was experimentally confirmed that the artificial muscle, if mounted at the middle port, could be driven smoothly even under the alternate voltage field application. Furthermore, the possibility of driving the fingers independently of each other was examined when fewer electrodes were used, and this method was proved to be practically applicable.