Mechanical amplifier design for piezo-actuator applications

In the use of piezoelectric actuators in precision instrumentation, manufacturing and mechatronics, piezo-materials can only provide a very small range of displacement which is hardly sufficient to meet the requirement directly. In order to overcome this disadvantage, a mechanical amplifier is normally used. The flexure hinge displacement amplifier has numerous advantages, such as smoothness of movement, no need of lubrication and zero backlash. In most cases, therefore, the use of a flexure-hinged mechanical displacement amplifier is the most appropriate approach to magnifying the output displacement of the piezo-actuators. Flexure-hinged displacement amplifiers are divided into two groups; precision oriented and displacement oriented, according to their application. Three basic topologies of flexure-hinged structure are introduced which provide the elemental components of the majority of compound amplifiers. The performance of different flexure hinge profiles is studied by using finite element methods, in terms of flexibility and accuracy. Finally, a simple lever displacement amplifier is designed for piezomotors and its dynamic performance is discussed.