Adaptive secondary mirrors upgrades at the Large Binocular Telescope

With the exception of the two prime focus cameras, all the instruments on the Large Binocular Telescope (LBT) use the two advanced 672-voice-coil-actuators adaptive secondary mirrors (ASMs). Based on 10 years of ASMs operation experience, and taking advantage of new technology developments, we decided to upgrade some of the ASMs hardware, to increase their performance and reliability. In this paper, we describe these improvements, i.e., upgrade of the power backplanes used in the ASM electronic control system, integration of an accelerometer-based tip-tilt vibration suppression system and upgrade of the optical calibration interferometers.