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Posted: August 27, 2009
Optical Path Control, Beam Steering and Image Stabilization with Lower Cost Piezo Controller
(Nanowerk News) Piezo system specialist PI has extended its E-616 multi-channel controller line for piezo based steering & stabilization mirror platforms. Four open and closed-loop models are now available in bench-top and OEM module versions. The closed-loop units contain two servo controllers, sensor circuit channels and 3 power amplifiers.
E-616 OEM controller with S-330 steering mirror platforms and E-616 bench-top with S-334 steering mirror.
Features and Advantages of the E-616 Multi-Axis Controller
Three Integrated Amplifiers Provide up to 10 W Peak Power
Closed-Loop and Open-Loop Versions
Bench-Top and OEM Modules
Internal Coordinate Transformation Simplifies Control of Parallel Kinematics Designs (Tripod & Differential Drive)
Piezo Steering Mirrors: Why?
Piezo steering mirrors are faster than galvo mirror scanners and provide improved resolution and stability due to their high-stiffness, solid-state piezo drives. They are used to steer or stabilize beams or enhance image resolution. Applications range from optical commumication, astronomy and super-resolution microscopy to nano-lithography.
Tripod and Quadra-Pod Differential Drive Versions
The controllers can drive parallel-kinematics (highest performance mechanics, where all piezo actuators are connected to the same moving platform) steering mirror designs. With the tripod design (for S-325 Z/Tip/Tilt mirrors), the platform is driven by three piezo actuators at 120° spacing. The quadra-pod differential drive design (as used in the S-330, or S-334 mirror models) runs two orthogonal axes with a fixed pivot point based on two pairs of actuators operating in push / pull-mode. The differential evaluation of two sensors per axis improves linearity, stability and resolution.
Internal Coordinate Transformation Simplifies Control
Parallel-kinematics requires the transformation of the commanded tilt angles into the corresponding linear motion of the individual actuators. In the E-616, this is taken care of by an integrated circuit, eliminating the need of additional external hardware or software. Additionally, with the E-616.S0 tripod version, all actuators can be commanded by an offset-voltage simultaneously. As a result, a vertical movement, for example for optical path length tuning, is obtained.
Simple Setup and Operation
To facilitate integration, setup and operation the E-616 features both front and rear panel connections: The 25 pin sub-D piezo & sensor connector is located on the front, along with offset trim pots and LEDs for Power and Overflow. A 32-pin rear connector allows commanding and reading the sensor and amplifier monitor outputs.