Plant modeling for observer-based control of the link stabilizing units at the European X-ray Free-Electron Laser

摘要

The European X-ray Free-Electron Laser will generate ultra short laser light pulses in the femto-second range to perform experiments with atomic scale resolution. A clock signal synchronizes all components and is distributed by a laser pulses train. These pulses are carried by an optical fiber which is spread through the facility and exposed to external disturbances which change the optical length of the fiber. It is of dire importance to keep this length stable because a change directly results in a timing error of the attached device. For this purpose Link Stabilizing Units are used. This paper shows the modeling of this unit, analyzes their main properties and points out the main control challenges.