Active vibration isolation system based on the LADRC algorithm for atom interferometry.

A new, to the best of our knowledge, method based on the linear active disturbance rejection control (LADRC) algorithm is proposed to design and build a vertical vibration isolator below ${0.1}\;{\rm Hz}$0.1Hz for cold-atom interferometry. This system combines the control system that is used to process and to reduce feedback vibrations measured by a seismometer and a voice coil that is used to cancel the motion of a commercial passive vibration isolation platform. When the feedback is on, the vertical vibration is reduced by an additional factor of up to 1000 from 0.1 to ${5}\;{\rm Hz}$5Hz, while the system has a steady oscillation with a natural period of 66 s. The experimental results show that the LADRC is an effective control algorithm for this application and performs better than the classic lag compensation filters in our case. In addition, there are fewer parameters to adjust in this method, and we only need to tune the feedback gain of the system state error for its application.