Nano- Precision Actuator Systems & Solutions

Click here for more information on nano-actuators.

PI is the leader in ultra-precision motion control systems and has more experience designing, manufacturing and supporting piezo based ultra-low inertia Nano-Positioning Actuator systems than any other company in the world. In the last 30 years we have delivered tens of thousands of standard and custom systems to OEM and research.

To satisfy the needs of our customers, we often had to come up with revolutionary solutions in manufacturing and control technology.  Engineers at PI have been working on nano-precision solutions long before Nano-Technology became a buzzword.

Read on for details, 
click here for the Nano-Positioner Selection Guide on the PI Website
Click here for Custom Nano-Positioning Solutions on the PI Website.

Ultra-Low-Inertia Nano-Positioning

Click here for Nano-Positioner Selection Guide
Variety of Single and Multi-Axis PZT Nano-Positioning Stages.
PI offers the largest variety of custom and standard ultra-low inertia Nano-Positioning Solutions. 

Examples for Parallel-Kinematics Nano-Positioning Systems 

Ultra-Low-Inertia Nano-Positioning Systems, Ultra-High Precision Position Sensors

Ultra-low-inertia solid state PZT Nano-Positioning stages can repeatedly move bidirectional nanometer level steps, up to hundreds of Hz if required. 
Two plate capacitive position sensors ensure highest linearity and longterm stability. 
These absolute measuring, nont-contact  sensors detect motion at sub-nanometer levels directly (direct output metrology) and provide superior accuracy, linearity, resolution, stability and bandwidth to Strain Gauge type sensors (Piezo Resistive Sensors) LVDT sensors and incremental encoders (glass scale type encoders).  If used in parallel-kinematics multi-axis systems, they can also provide the information for an automatic runout-compensation.

Minimized recoil forces are a by-product of the ultra-low inertia approach.  Classical Micropositioning stages, even when equipped with high-resolution encoders cannot achieve this precision.  The high inertia, friction, and servo dither prevents fast motion at the nanometer level.

Click here for more information on PI Capacitive Position Sensors 

Vibration Elimination

The example above shows ringing of a poorly damped component on a high-speed Nano-Positioning stage.  While the closed-loop Nano-Positioning stage settles perfectly, the component cannot keep up. Conventional solutions to this problem would suggest slowing down the Nano-Positioning stage.  Macheliminates ringing without sacrificing speed. 
It does not even require retuning of the servo system.

Mach Throughput Processor Eliminates Self-Generated Vibration, Increases Troughput, Scanning Speed, Accuracy. 

The exclusive Mach Throughput Processor eliminates resonant ringing, allowing rapid motion without settling. This technique also eliminates resonances excited in neighboring components outside the Nano-Positioning system's servo loop.  The result is significantly increased throughput. 

Self-generated vibration affects:

  • The load and fixturing that the Nano-Positioner actuates, 
  • The supporting structure to which the Nano-Positioner is mounted, and
  • All other components attached to the supporting structure.

The example above shows vibrations induced at the beginning of a saw-tooth scan, typical in image acquisition applications. The vibration results in lower image quality.  Mach™ improves the image quailtiy; there is no need to reduce the scanning frequency or changing the mechanical components in the system.

Mach™ is available as an option for several PI Digital Piezoelectric Controllers and also as an upgrade option for analog controllers.

If you need to achieve nanometer precision faster, request our technote on 
Mach and talk to a PI application engineer:

This technology is protected by one or more of the following US and foreign Patents licensed from Convolve, Inc.: US 4,916,635; US 5,638,267; 0433375 Europe; 067152 Korea, and other Patents pending.  Mach™, Throughput Coprocessor™ and NanoAutomation® are trademarks of Polytec PI, Inc.  Input Shaping™ is a trademark of Convolve, Inc.
Trajectory Control

Active Trajectory Control.

Active Trajectory Control is available on single module parallel-kinematics Nano-Positioning systems. It improves straightness and flatness to sub-nanometer precision. Digital controllers with advanced coordinate transformation algorithms allow active trajectory control for up to 6 DoF. 

If you need ultra-precise motion, straighter or flatter, request our technote 
and talk to a PI application engineer:

  508-832-3456 (EAST)
  714-850-1835 (WEST)



Adaptive Preshaping/ Auto-Learning Controllers

Preshaping algorithms and adaptive following-error elimination algorithms can increase the linearity and effective bandwidth of high-speed Nano-Positioning systems by up to 10000%.  This translates into higher dynamic accuracy, and increased throughput. 

Applications range from out-of-round machining (pistons, contactlenses, optics) to scanning microscopy.

If you need higher linearity in dynamic nanometer-level motion systems,  request our technote and talk to a PI application engineer:

  508-832-3456 (EAST)
  714-850-1835 (WEST)


Flexure Technology

Flexures, if designed properly, are very robust, maintenance free, and provide sub-nanometer-level guiding precision (simple designs induce cosine runout errors).  They are frictionless and do neither require lubricants nor air. 




Not all flexures are created equal!

PI multi-axis Nano-Positioning systems are based on wire EDM cut parallel-kinematics 
Pro: Simple. 
  • Slower response (lower stage carries inertial mass of upper stage);
  • Non-symmetric resonant frequencies (lower stage is slower than upper stage, requires different servo settings).
  • Orthogonality error is mounting-angle dependant.

  • Runout in Y cannot be monitored/compensated by the sensor in the X stage or vice versa.
A) Stacking 2 single-axis stages
Better response than A) but still non-symmetric and X and Y work without "knowledge" of each other. B) Single module (monolithic) but nested (serial) X and Y.
Best solution. 
  • Same ultra-low inertia for X and Y motion, providing higher responsiveness and axis-independent performance. 
  • Excellent, mounting independent orthogonality. 
  • Reduced runout: X sensor (PI uses non-contact two plate capacitance sensors) can monitor and correct for Y runout and vice versa. 

  • Additional rotation axis (Theta z ) feasible with 3 actuators / sensors and digital controller.
C) Single-module parallel-kinematics X and Y (with crosstalk compensation).

Click here for the Nano-Positioner Selection Guide on the PI Website
Click here for Custom Nano-Positioning Solutions on the PI Website














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