Systems and methods here may be used to support a femtosecond laser eye surgery system including utilizing a floating head and/or patient support to maintain alignment of the system with a patient using feedback loops of force sensors in a patient interface. In some examples, the floating head and/or patient support may counteract movements detected in the force sensors. In some example embodiments, a ranging subsystem may detect and compensate for different arrangements of the floating head assembly using a ranging sample beam.
