  Future large segmented space telescopes and their coronagraphic instruments
are expected to provide the resolution and sensitivity to observe Earth-like
planets with a 10^10 contrast ratio at less than 100 mas from their host star.
Advanced coronagraphs and wavefront control methods will enable the generation
of high-contrast dark holes in the image of an observed star. However, drifts
in the optical path of the system will lead to pointing errors and other
critical low-order aberrations that will prevent maintenance of this contrast.
To measure and correct for these errors, we explore the use of a Zernike
wavefront sensor (ZWFS) in the starlight rejected and filtered by the focal
plane mask of a Lyot-type coronagraph. In our previous work, the analytical
phase reconstruction formalism of the ZWFS was adapted for a filtered beam. We
now explore strategies to actively compensate for these drifts in a segmented
pupil setup on the High-contrast imager for Complex Aperture Telescopes
(HiCAT). This contribution presents laboratory results from closed-loop
compensation of bench internal turbulence as well as known introduced
aberrations using phase conjugation and interaction matrix approaches. We also
study the contrast recovery in the image plane dark hole when using a closed
loop based on the ZWFS.
