The closed loop proportional-integral-derivative controller (PID controller) is implemented for position loop using the feedback from linear optical encoder. In addition to this, drive board also contains a decoder, current sensor and related circuitry to get the position and other feedbacks. We have also designed and developed a customized actuator drive board which comprises power electronics to handle the voice coil motor (VCM), off-loader as well as snubber stepper motors. The actuator controller is implemented around a single board computer called SBC6845. The paper describes our effort to develop a precision actuator controller at India TMT Coordination Centre (ITCC) laboratory, Indian Institute of Astrophysics, Bangalore. These commands are executed at individual actuator locally by a precision controller. The global loop controller does this by sending commands to the actuators to move within few nanometers.

TL DR: In this article, the authors have developed a precision actuator controller at India TMT Coordination Centre (ITCC) laboratory, Indian Institute of Astrophysics, Bangalore using a single board computer called SBC6845.Ībstract: The segmented mirror telescopes are built using small hexagonal mirrors positioned and aligned by the three actuators and six edge sensors per segment to maintain the shape of the primary mirror.

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