figure 1: Lorentz actuator (left) and compensation module (right)

The unconstrained translation of each axis is actuated with a Lorentz type duo-motor. The rectangular coil of this actuator (57 N/A) is integrated into the ceramic boxshaped bridge of the parallelogram to maximize the stiffness in the direction of actuation (figure 1). Permanent magnets are suspended above and below the coil by bridge-like supports.

Elastic straight guides have some residual stiffness in the direction of translation. This residual stiffness (2800 N/m) would lead to larger forces in the actuator and would result in over 0.5W dissipation near the maximum stroke position. This is avoided by adding weight and stiffness compensation mechanisms.

A prototype has been built to test the performance of the actuator and compensation mechanisms. The stiffness compensation mechanism reduces the required maximum actuator force by over 98% which limits the maximum power loss to less than 1 mW.

back to overview interferometers mirrors beam delivery sampleholder straight guides actuation