英语翻译

英语翻译
1.Introduction
A stack-type piezoelectric element,hereafter referred to as a piezo stack,is a multilayer piezo-ceramic column integrated by many thin piezo-ceramic plates which have a parallel electrical connection.The piezo stack is deformed along the longitudinal direction when a voltage is supplied to it,since the piezo-ceramic plate is polarized longitudinally.The piezo stack is a typical actuating source for fine motion generation in the range of several microns,since it has the characteristics of high force,high resolution,fast response and small displacement.Dueto these characteristics,the piezo stack as the actuating source is applicable to stages,scanners for ultra-precision positioning,and precision machining centers [1–13].Compliant mechanisms implemented by flexure hinges are applicable to nano-motion stages.The compliant mechanisms are integrated with piezo stacks for actuating source and high resolution
displacement sensors [7–13].The compliant mechanisms
play the role of motion guide and/or displacement amplification
in the nano-motion stages.The flexure hinges are elastic members
connecting objects or links [14–16].Since the flexure hinges
are elastically deformable,the objects are movable with respect to
each other.The flexure hinges are generally manufactured monolithically
by an etching process,wire electro-discharge machining,
or jig boring.Since the flexure hinges have the advantages of linear
force-displacement relation in an elastic range and contactless continuous
motion,they are useful in the compliant mechanisms for
high frequency scanning and ultra-precision positioning at a small
range.The flexure hinges can be categorized into a simple flexure
hinge and a compound flexure hinge.The former is distinguished
by the shape of the notch as a circular notch hinge,an elliptic notch
hinge,a leaf hinge,etc.[14,15].The latter,which is a kind of a compliant
mechanism,is composed of a parallel combination [14] of
simple flexure hinges.Generally,the compound flexure hinge is
applicable to a joint for larger deformation than the simple flexure
hinge.
The displacement of the piezo stack is at most 0.1% of the
length of the piezo stack.Since some applications require a working
range that is longer than the displacement of the piezo stack,
mechanical amplification mechanisms are employed in the nanomotion
stage.These mechanisms are classified into a leverage
mechanism and a flextensional mechanism [17].Whereas the volume
of the former mechanism increases with the amplification
ratio,that of the latter one does not depend on the amplification
ratio.The flextensional mechanism has a more compact
structure than the leverage mechanism for a high amplification
ratio.