Nanostage advantages at a glance
• Excellent repeatability of only several nano metres at miniaturised dimensions
• No loss of position in the event of a power failure
• Low wear since the drive principle is non-positive
• Stepper motor drive permits open loop control
• No additional measurement system necessary
• Operates with a simple, cost effective stepper motor driver
• No overshooting during positioning
• Supply voltage in low-voltage range
• Can be used in ultra high vacuum
Nanostage vs. piezo actuator
Most positioning systems having a resolution of only a few nano metres are based on the piezoelectric effect and these cause several problems:
• Loss of position when there is a power failure
• Localised wear, particularly in inchworm drives
• Direct measurement system is necessary
• Requires an expensive controller
• Overshooting during positioning
• Shorter travel range with respect to model size
The idea behind the nano actuator is based on a combination of conventional servo motor technology and the high precision of flexure hinges. This makes the drive's behaviour calculable and easily controlled.
Nanostage makes it possible
The distinctive feature of the "Nanostage" nano positioning system is its combination of highly precise, high resolution eccentric mechanism with a kinematics structure of monolithic flexure hinge. The eccentric mechanism is formed by a combination of stepper motor and a micro Harmonic Drive® gear; thus allowing simple control technology, yet providing for very high resolution as a consequence of the extremely high 1000:1 reduction ratio.
The flexure hinge functions
The guide system is formed by two parallel flexure hinges, suitable for movements in the range of only a few nano metres. An additional lever mechanism reduces the large movement of the eccentric mechanism to produce motion in the single-digit nano metre range.
Flexure hinge — secure without assembly faults
The flexure hinges have a monolithic structure. This does away with the need for assembly and removes the influences away with the need for assembly and removes the influences of assembly faults such as asymmetrical mechanical tension in the hinges.
The kinematic chain comprises the following components:
• A micro stepper motor having 20 full steps (40 half steps) per revolution
• A high reduction micro Harmonic Drive® gearbox with a reduction ratio of 1000:1
• Eccentric mechanism with 1 mm of eccentricity, fitted with preloaded ball bearings
• Monolithic lever as a compliant mechanism with a further reduction of 50:1