Deformable Mirror Controller

Kilo DM Controller development

Eduardo Bendek and Pedro Godoy
Contact: eduardobendek at gmail. com

V2.0 April 1st, 2015

Goal

Develop a compact DM controller for the Kilo DM that can:

  • deliver at least 14bit resolution over a 200V dynamic range at frequency faster than 1kHz.
  • The controller will be directly integrated with the Zif Socket eliminating the need for cables and providing a direct mechanical connection from the bench mount to the DM. The controller
  • The controller will have a volume of 4”x2”x1” and only uses less than 6W and weight less than 0.5kg.
  • It has a simple 12V power supply and a USB 3 interface for the data.
  • DM remapping is built in.
  • Is design to be space qualified.

Current demonstration of Kilo DM Demo controller 96 actuators:

The Kilo DM Controller Demo is a fully integrated and fully operational system, but with only 94 active channels. The software accepts standard 32-bit FITS files. The hardware only requires a 12V power supply and a USB connection with the host computer. Only 96 channels were enabled to minimize cots and demonstrate functionality of the technology. The controller is only 4”x2”x1” and only uses 4.5W and weight less than 0.5kg.

Screenshot 2015-04-17 13.28.45
Fig. 1: Kilo DM Mirror controller: Left: high voltage board (Blue), Center: microprocessor, Right: Controller assembled with Kilo DM Mounted.

Kilo DM Demo controller testing: The controller was able shape the surface of the mirror. Lack of information about actuator remapping prevented us from achieving smooth surfaces, however the technical functionality has been successfully demonstrated as shown in Fig. 2 and 3.

Fig. 2: Left: Flat DM, no voltage. Center: 60V applied to 96 actuators which are not contiguous because we don’t know the actuator remapping and therefore there are actuators that we cannot control.
Fig. 2: Left: Flat DM, no voltage. Center: 60V applied to 96 actuators which are not contiguous because we don’t know the actuator remapping and therefore there are actuators that we cannot control.
Fig. 3: The surface shown in Fig. 2b was used to as “flat” and subtracted from the new measurements when only one actuator was activated at a time.  The top figure shows 0V background and 60V on the actuator  and the middle one show 0V and 120V respectively. The bottom image shows +60V applied to the whole DM and 0V on the actuator making poking it up.
Fig. 3: The surface shown in Fig. 2b was used to as “flat” and subtracted from the new measurements when only one actuator was activated at a time. The top figure shows 0V background and 60V on the actuator and the middle one show 0V and 120V respectively. The bottom image shows +60V applied to the whole DM and 0V on the actuator making poking it up.

For this project we have developed Windows software to control the DM from any laptop. The software was successfully tested in the lab computer and it can operate with standard FITS files that LabView generates so it can replace the current controller without any software changes.

DM Demo Controller Conclusion:

The development of a compact DM controller for a BMC Kilo-DM mirror has been successfully demonstrated. Our next step is to build a controller with same specification can be built to control 1032 actuators and still fit in the same compact enclosure.

Fig. 2: Kilo DM Mirror controller software interface
Fig. 2: Kilo DM Mirror controller software interface

Kilo DM full size Controller proposal

The Kilo DM Controller is a fully integrated and fully operational system with 960 channels. The software accepts standard 32-bit FITS files. The hardware only requires a 12V power supply and a USB connection with the host computer.

Screenshot 2015-04-17 13.29.48

Preliminary footprint:

 The design considers a 12-Layer Flex-Rigid PCB with soldered Zif socket. Final footprint is subject to further evaluation, but should be close to images below.

Screenshot 2015-04-17 13.29.25

There are two alternatives of compact and highly integrated ICs that may be utilized. However, stock availability is limited and must be secured after the acceptance of this proposal. Final footprint is conditioned to ICs availability.

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