This study developed the feedforward control strategy of the piezoelectric micro-stage integrated with a bridge-type compliant mechanism. The micro-stage was assembled with three actuator legs and a moving plate. The actuator leg was consisted of four piezoelectric actuators with compliant mechanism. However, the complex nonlinear coupling between piezo-actuators and the compliant mechanism caused the hysteresis which can obstruct the precise control. The hysteresis of the piezoelectric micro-stage was realized by the 3rd order polynomial model in this study. Furthermore, the polynomial model was revised to consider the hysteresis change depending on the rate of input voltage. The compensator based on the revised polynomial model was designed for the feedforward control. The performance of the compensator was evaluated while changing the input voltage rate. Experiment results show that the tracking error of the compensator with the rate-dependent model quite decreases in compared with the rate-independent model. The feedforward control based on the revised polynomial model can be successfully utilized to the piezoelectric micro-stage regardless of the input voltage rate.
Interest in soft actuating mechanism using by soft elastomeric materials is gradually growing for next-generation devices such as wearable electronics, haptic feedback systems, and soft robotics. However, for more practical and feasible applications in diverse devices, soft and flexible actuators require multi-functionalities. Here, we report the morphological variation of void-patterned dielectric elastomer actuators with mechanically stretchable AgNWs electrodes on elastomer surfaces, utilizing simple void-patterning process. In macroscopic view, the actuator showed one-directionally deformed actuation properties in pre-patterned void-direction. And, the ridges and vertices of the deformed surfaces were observed under the control of an input voltage to the elastomer haptic interface. In addition, the variation in the morphology of the stretchable electrodes deposited on elastomer film under various electrical input were verified by measuring the vertical displacement of the elastomeric actuator, showing the surface roughness, from 0 to 120 um along the void-direction. Also, the deformed-area can be controlled by AgNWs electrode patterning. The present study successfully demonstrated the elastomeric actuator performance under electrically controlled inputs, which were used to modulate the elastomeric surfaces with continuous roughness levels. These results reveals that the morphological variation of the flat surface can be applicable to haptic interface for regenerating surface texture.