Study On Electrorheological Transmission Mechanism With Ripple-shaped Disc

Electrorheological(ER) technology is an innovative electromechanical-hydrau lic technology. Based on the electric-controlled performance of ER fluids, ER technology is expected to make revolutionary change to some traditional technology. The technology has significant advantages as following: simpler structure, quicker response, better controllability and intellectual technology. As the research has developed greatly these years, ER technology has being attracted more and more attentions from scientists and engineers in the world.As we know, the key problem to restrict ER technology to be used in drive and brake applications is that torque transmitted by ER device is not enough to meet the needs in engineering implementation due to low field-dependent stress of ER materials. Having surveyed and covered a vast amount of engineering literature, the present author has found that there is few researchers who worked to solve the problem by means of optimizing mechanism configuration.The objective of this work is to study how to improve transmitted torque caused by ER effect (named ER torque) of ER actuator by means of changing surface shape of drive disc electrode. In this dissertation, the ripple disc is proposed to replace traditional plate disc for operating in shear-squeeze-flow mode. This configuration is presumed to be able to enhance ER torque compared with ER actuator with double discs in which ER fluids are operated in shear-flow mode.To put it more systematically, the present dissertation has been accomplished in the following ways.As the first step, ER fluids were made and material characteristic dependencies, including shear stress, dynamic viscosity, on changes in the applied external electric field, shear rate were measured and examined in the reformed apparatus of NXS-11Acylindrical viscometer.As the second step, in order to investigate the difference of ER torque between shear-flow mode and shear-squeeze-flow mode, a special equipment named single-disc ER actuator and some ripple discs with different shape had been designed and manufactured. Experimental setups also consists of: torque transducer, data acquisition system based on the National Instruments programming package, source of high voltage (AC/DC voltage resource) and adjustable-speed motor, etc.As the third step, a conformal transformation approach was employed to derive expressions to calculate the electric parameters including capacity, electric field in the plate-ripple disc of ER actuator configured by a driving plate disc and a driven ripple disc. On the other hand, the flow of ER fluids between plate disc and ripple disc was discussed in detail. The resulting analytical model is capable of predicting the relationships between the transmitted torque, including ER torque, and the characteristic parameters of ER fluids as well as configuration parameters of the mechanism.As the fourth step, a series of experiments for examining ER torque transmitted by the plate-ripple disc and the double-plate disc of ER actuators had been carried out. Many experiments data had been given for comparison with our calculations based on the analytical model in previous section. As a consequence, under the same conditions of ER fluids, mean fluid gap size, loading electric voltage, rotational speed of discs, we can make a conclusion that the plate-ripple disc can provide multiple ER torque than the double-plate disc of ER actuators. Good agreement was achieved between predicted results and measured results. Furthermore, the variation of the ER torque with electric field and rotational speed of discs was obtained in the work. In addition, ER power (power caused by ER effect), leakage current and leakage power had also been investigated.ER transmission system is a nonlinear and time-variant system and neural network, which is known to be very effective for the uncertain control system, was employed to model ER device. However, this algorithm is not capable of expressing the characteristic of ER device. At the end of the work, a new algorithm incorporating genetic al...