Industrial Line
PAGE 312
Working Principle
1. A drive element is firmly connected with a piezo actuator which is placed in frictional contact with a movable
table. A sawtooth shaped voltage pulse is applied to
the piezo.
2. During the phase of the slow flank the movable table
sticks to the drive element and is moved over a distance
Δx. The achieved expansion Δx is proportional to the
applied maximum. The typical minimum step size for
ECS positioners is 50 nm.
3. By applying the steep flank of the voltage pulse to the
piezo, the drive element is accelerated very rapidly
over a short period of time, so that the inertia of the
movable table overcomes friction. This way, the table
disengages from the accelerated drive element and
remains nearly non-displaced. The net step Δx is now
completed.
By repeating this procedure the table can be moved
over large distances with nanometer precision.