Benefits of Piezo Flexure Stages

Flexure stages employ a flexure bearing mechanism as a foundation for motion control. A moving platform is connected to the static base of the stage by flexure hinges. The moving platform is driven by piezo actuators to achieve desired motion. Guiding motion is provided by the deformation of the flexure material. This linkage is virtually friction and stiction free, which creates smooth, flat, repeatable motion. Using finite element analysis allows the flexure design to be optimized, resulting in high stiffness and greater load capacity. This optimization simultaneously reduces parasitic errors such as out-of-plane motion, rotation, tilting, and cross talk. Flexures do not experience frictional wear, thus eliminating routine maintenance issues. Consistency is maintained over the operational lifetime of the stage with the potential of billions of cycles or more.


Example Flexure Cut in a Tip-Tilt Piezo Stage

The driving piezo stack actuators produce motion of about 0.1% their overall length. Limited stroke and stage footprint requirements make it imperative to design some flexures with an amplification factor to increase a stage’s travel range. Amplification allows stages to be built smaller and more economically, to fit within the constraints of various applications.

Although piezo actuators provide great resolution, there can be drawbacks including creep, hysteresis, non-linearity, and repeatability. Employing a closed-loop system helps eliminate these issues by using a sensor and controller to achieve desired position. Closed-loop control can also improve response rates in step and settle applications and help control waveforms while scanning. Calibrating a piezo flexure stage in closed-loop allows for the linear repeatable motion often desired in nanopositioning applications.

Benefits of Piezo Flexure Stages

  • Great Reliability
  • High-Speed Motion
  • Billions of Cycles
  • Excellent Step and Settle Times
  • Smooth Motion
  • Nanometer Positional Accuracy
  • Low Friction
  • Operate in UHV Environments
  • Limited Tilt and Rotation
  • Low Out-of-Plane Motion
  • Long Term Stability
  • Can Be Non-Magnetic

Possible Drawbacks

  • Speed is Limited by Mechanical Resonance
  • Travel is Limited to a Few Millimeters
  • Limited Axes of Motion
  • Power Must Be On to Maintain Position

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