The characteristics of variable speed inchworm stage using lever mechanism by different materials

Currently, piezoelectric actuators which have attractive features such as high output force, high positioning resolution, high stiffness and quick response have been used in many ultra precision stages. But their positioning ranges are very small. This very limited displacement severely restricts the actuator's immediate implementation for long-range positioning. This paper shows a variable speed inchworm type stage with hinge structures as lever mechanism for nanometer resolution with large dynamic range and studies on characteristics of it. The inchworm stage has hinge structure levers which can shift their pivot position. And it can amplify/reduce output displacement using mechanical advantage with a lever. Especially we suggest guide-line of design according this work that was performed using different materials of stages (Aluminium and Stainless Steel). As the results of simulations, the larger lever ratio is, the smaller stiffness of lever portion is. As the results of experiments, when we input voltage into the inchworm stage, output displacement of each lever is different according to material. Hysteresis of stage could also present that grow according as lever rate rises and stiffness of material. In the case of feeding speed, Aluminium with less hardness showed excellent responsiveness, hence excellent feed performance results.