Keywords :
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Nanopositioning, Piezo-actuators, closed loop
system, controller, Integral of errors.
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Abstract :
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“NANOTECHNOLOGY is the design,
characterization, production and applications of structures,
devices and systems by controlling shapes and size at nanometer
scale.” One of the most important requirement of
nanotechnology is precision control and manipulation of devices
and materials at nanoscale i.e. nanopositioning. Nanopositioners
are precision mechatronic system designed to move objects over
a small range with a resolution down to a fraction of an atomic
diameter. In particular, desired specifications of any
nanopositioners are fast response with no or very little overshoot,
large travel range with very high resolution, extremely high
precision and high bandwidth. This paper presents design and
identification of nanopositioning device consisting of flexure
stage, piezoelectric actuator and displacement laser sensor. Open
loop behavior of the nanopositioning device on the basis of time
and frequency responses is studied. To improve the system
characteristics feedback controllers are used. The key of the
controller is to design a system with good dynamic
characteristics as well as to maintain the desired stability
margins. Despite continuous advancement in control theory,
Proportional Integral Derivative (PID) controller is the most
popular technique to control any process. To provide consistent,
reliable and safe solution to the industrial control problems
work, in this paper, Proportional (P), proportional- Integral (PI)
and PID controllers are designed to minimize integral of errors.
System performances for the desired parameters in closed loop
are investigated. Comparative analysis of different controllers on
the basis of time and frequency response is given. Simulation of
results for the performance analysis is carried out in MATLAB.
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