Moving with Nanometer Accuracy
Precision positioning is a key enabling technology for various industrial sectors, such as semiconductor and optoelectronics, and research and development applications ranging from microscopies, optical instruments, to material manipulation. Once a positioning precision of better than one micrometer is needed, piezo-driven actuation has established itself as the leading positioning technology. This is particularly true for applications under vacuum and cryogenic conditions where conventional motor drives fail to operate reliably.
Our Quano nanopositioning stages are based on the stick-slip drive. The stick-slip drive is an inertial motor mechanism utilising piezo-actuated motion to realise travel distances from millimetres to centimetres with high repeatability while offering smallest step sizes on the order of 10 nanometers.
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The Stick-Slip Drive
The stick-slip drive mechanism is schematically illustrated above. It is based on a translation axis (blue), which is firmly connected to a fixed base (white) via a piezoelectric chip (red) and a carriage (yellow), which is clamped to the translation axis. Through this clamping, the carriage forms a friction interface with the translation axis enabling an piezo-actuated bilinear motion. This motion is realized through the application of a sawtooth voltage waveform to the piezoelectric chip.​​​​​​​​​​​
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During the rising flank of the sawtooth signal, the piezoelectric chip expands. The carriage sticks to the translation axis through the interfacial friction, and it is displaced by a finite distance given by the expansion of the piezoelectric chip. The higher the applied voltage amplitude, the larger is the achieved displacement.
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During the steep voltage drop of the sawtooth waveform, the piezoelectric actuator contracts rapidly and the inertia of the carriage overcomes the friction between the carriage and the translation axis. Hence, the carriage remains stationary, and a finite displacement is realized through one sawtooth waveform cycle.
The continuous application of sawtooth voltage waveforms permits the continuous displacement of the carriage over long distances.