Drive System report. Overview. Drive II. Drive Stereo. Current accuracy. Outlook

Transcription

1 1 Overview Drive II Drive Stereo Current accuracy Outlook

2 2 MAGIC II No changes since last meeting except: The signal opening the elevation break is now disconnected in the hardware if the emergency switch for the motor break is opened The door switch is connected (but only for one door available!)......but not yet implemented in the SPS software (we ran out of time)

3 3 MAGIC II When checking the emergency procedure we found out that not in all circumstances (e.g. wind, ) it is possible to move the telescope manually! THIS IS DANGEROUS! We would propose to add a bevel gear with a continuous shaft between the motor and the planetary gear Suggestion NOW Motor Bevel gear (~1:1) with continuous shaft Planetary gear (1:20) Cogwheel (to telescope axis ~1:60) Crank

4 4 MAGIC II Disadvantage: Costs Workshop power needed Advantage: Safety Easy to build Low costs Cost/axis: 1500,- bevel gear (with clutch) 2x300,- for axis connectors Small parts and workshop material Suggestion NOW Motor Bevel gear (~1:1) with continuous shaft Planetary gear (1:20) Cogwheel (to telescope axis ~1:60) Crank

5 5 MAGIC I To operate both telescopes in stereo mode it made sense to have two identical systems (especially for maintenance) I planned a two week trip to La Palma together with Carsten (help with updating the circuit plan) and Daniela (she knows the MI drive system best) Two ING technicians were supposed to do the hardware upgrade They decided to recable the whole cabinet instead of doing an upgrade (which would mainly been removing obsolete cables) Working 4h to 5h a day and doing more than twice the work planed, the upgrade took more than two weeks Finally I had to shift my flight back by one week.

6 6 MAGIC I Advantages: I had a lot of time to make cosy2 work perfect for both telescopes and implement fixes and improvements I never got the time for before Also a few improvements to the SPS software could be implemented Disadvantages: We don't have any circuit plan now (they promised to provide it, but didn't do so far) This is (more or less) how the upgrade looked when I left the island (In my opinion this is NOT SAFE)

7 7 Status After the hardware was finished, I had three days left to get everything operative and fortunately after this time everything was working Both cabinets are now almost identical (the power section is still slightly different) The drive pc and the drive software is now identical Except a network problem (maybe a broken switch) everything is working without any error since I left the island We could get MI as 70% as fast as MII (remember: MII in GRB mode works now at the physical limits of the motors)

8 8 Status How can we make MI as fast as MII? First we need an inspection of the alignment of the motors and chains while moving fast,i.e. with cosy (not with the remote control) Peter and crew did the same for MII when I was on La Palma and found many details which needed improvement. (They realigned both azimuth motors to fit better into the chain) Then we need a procedure (either a technician from Rexroth or at least an instruction) to check how well the system behaves when moving fast (oscillations?) Whether parameters finally need adaption depends on how different the dynamics of the mechanics of MI and MII is

9 9 Status Just to remember: GRB mode of MAGIC II Maximum velocity: 2.80 rpm (Az) 3.15 rpm (Zd) Maximum acceleration: 0.03 rad/s² (Az) 0.09 rad/s² (Zd) Positioning time: 300 /30s 180 /20s Needs 84 to accelerate to 2.8 rpm

10 10 Status Currently... MAGIC I is slewing with 30% maximum speed, this is as fast as MAGIC II (Look at Michael's movie to see HOW FAST Magic II really is - impressive!) GRB mode of MI is 70% of the maximum (and 60% of the acceleration of MII) Remember: MAGIC II's GRB mode is at the limits of the motors GOOD NEWS: Due to mounting the new shaftencoder on the right tower, the culmination problem has almost vanished. It is now about four to five times smaller than before, i.e. in the same order than MII

11 11 Software Status Improvements in the stability (bug fixes) Improvements to the communication (it could hang cosy) Improvements to the starguider algorithm (accuracy) Moved all build-in numbers into a resource-file Implemented the automatic TPoint procedure (now Arehucas can trigger taking a Tpoint (includes starguider TPoint) Also the starguider mode can now be switched on (before the observations are started) automatically from Arehucas Now the binaries of MI and MII are identical (except that the Arming procedure is not yet enabled for MII) and all differences are coded in a resource-file. Due to plenty of time to test all these changes extensively

12 12 Pointing accuracy The shift crew (thanks!) took about 250 TPoints with MI and MII They all look very good (after waiting for only 30s after the telescope reached the pointing position!) Magic I Magic II Shaftencoder resolution of the old shaftencoders (~ 1 arcmin) Artifact from wrongly identified bright starsmagic (due Collaboration to a bias from misaligned Thomas Bretz, University Würzburg, Meeting, Elba, 2009 mirrors)

13 13 Pointing accuracy Please note: In reality (measured directly from the taken TPoints) the pointing is about 10% worse than suggested by the fit MAGICI: ~ ~35 MAGICII: ~ ~30 Development of measured residuals of MAGIC I (Quantiles: 50%, 68%, 95%) Best result so far After upgrade

14 14 Pointing accuracy Please note: In reality (measured directly from the taken TPoints) the pointing is about 10% worse than suggested by the fit MAGICI: ~ ~35 MAGICII: ~ ~30 The CCD camera of MI has many dead pixels already, which bias the measurement and might explain the difference (another explanation could be the less stiff structure of MI) Therefore, I propose to exchange the camera and measure the real mispointing again. (But we need a new starguider pointing model afterwards)

15 15 Summary We can hope that we can further accelerate MI and we can hope that with a new ccd we will improve its accuracy to the level of MII The upgrade of MI has improved Maintainability (two almost identical systems) Stability (everything is digital now) Accuracy (2/3 of the best value reached before) The culmination problem is now in the same order as MII (roughly four times smaller than before) Thanks to the help of Daniela, Carsten, Markus Gar. and the shift crew(s): MAGIC I and II are now well prepared for stereo tracking They have already been operated successfully in stereo mode (The differences are so small and they behave so identical that just from the display you don't see which telescope you are looking at. It seems that even the regulating oscillations are identical, i.e. that there is still room for little improvement)