K.G. Strassmeier, AIP
Robotization at DC
and its pre-requisites
Language definition
Robotization = an integral systemsengineering approach
„integral “ = science goal → environment → technology →
→ calibration process → operations model → data storage →
→ data transfer → analysis tools
„systems engineering“ = combines Optics, Mechanics, Electronics
and Software. Optomechatronsoftics.
Language definition
Computerization
• all active components are under one-way computer control (receive a command)
• all passive components also remain passive (e.g. mount alignment, telescope focus)
• execute commands upon arrival
Remote control
• some active components are under two-way computer control (receive and acknowledge commands)
• all passive components also remain passive (e.g. no feedback from e.g. bandwidth control)
• execute commands upon arrival
Automation
• all active components are under two-way computer control (receive and acknowledge command)
• input of „hard“ facts (e.g. „sun below horizon“, environmental status „ok“, „target above horizon“)
• execute commands from target scheduler (usually just a script or timeline)
Robotization
• all active components are under n-way computer control (receive and acknowledge command .and.
concert action with system status; e.g. do not attempt to observe target X if focus position is Y)
• all passive components are under n-way computer control (e.g. a mount alignment receives and
acknowledges commands .and. provides permanent status .and. may take action)
• execute commands from „intelligent“ scheduler (e.g. dispatch)
Human operator
Robotics concept of STELLA
STELLA Control System (SCS):
Granzer et al. (2004), AN
Need Infrastructure !
Pre-requisites for Robotization
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Un-interrupted and clean power supply
System-status knowledge at any time
System re-start procedure and hardware safe mode
Reliable intra-networking between active components
Environmental-status knowledge at any time
Data flow from detector to storage computer
Data transfer to local mass-storage medium
Data storage and pre-processing; back-up facility
Data reduction pipeline and transfer to analysis
computer
Un-interrupted and clean power supply
Most realistic choice:
central power supply, decentral UPS and filters
Concordia
• Diesel-driven generators
decoupled from life-support
system
• backup generator
• power grid
Projects/Observatories
• AC filter
• transformer if needed
• UPS tailored to project needs
(Ni/Cd battery banks,
Li batteries, Hydrogen cells ... )
System-status knowledge at any time ...
Two principal levels:
1. From sensor to local control and data-acquisition computer(s)
2. From 1. to „home“ system (=scientist at home institution)
Ad 1: Requires ...
Ad 2: Requires ...
• GPS signal
• local 1-GB ethernet
• Small-bandwidth satellite conn.
• (or) Iridum phone „dial in“
(+ switches, repeaters, fibers...)
• network maintenance
• backup system
(e.g. micro-wave backbone)
System re-start procedure and hardware safe mode
parking („orderly shutdown“)
Most vulnerable components:
• SCSI-connected components like tape robots, RAIDs …
• Ethernet-connected peripheral components
• Serial components, e.g. monitor not recognizable because „dead“
• Controllers give wrong status because of previous power failure
• Encoder zero points get srewed up after power failure
Possible solutions:
Save storage of reference set ups on independent boot hardware.
Engage a self-calibration procedure.
Engineering console easily reachable.
Environmental-status knowledge at any time
Weather data must be known in (near) real time
Argentini 2006
Environmental-status knowledge at any time
Reliable intra-networking between local
computers
1. Ethernet (fiber vs. twisted pair)
2. RS232/486
Ad 1:
• Requires switch, repeat.
• Temperature sensitive
• Power over ethernet
• high bandwidth
Ad 2:
• direct connector, no hubs
• low bandwidth
• robust
• but remote boot problem if
too slow
Data flow from detector to computer
e.g. from ICE-T CCD to computer hard disk:
2x112Mpx CCD:
Integration time:
Read-out-time:
2x225 MB/image
10 sec
6.4 sec
with 50% safety:
Requires:
transfer in 5 sec, then acknowledge
45 MB/s or 450 Mbps
100Base TX Ethernet link not sufficient
Data transfer to local mass-storage medium
What speed is needed?
e.g. ICE-T:
450 MB/16.4sec = 27 MB/s
2x loss-less compression: 14 MB/s
HP Storageworks Ultrium 960 SCSI,
80 MB/s for 400-GB SDLTs
But 512-GB SDLT tapes needed
If tape writing fails, one looses data
after approx. 48 hours
Data storage and pre-processing;
data back-up facility
Pre-processing leads to level-2 data. Store only level-2 data?
e.g. ICE-T:
Combine always 30 CCD frames
Keep only „Master flat“
Rules out certain additional sciences!
Solution would be to store level-2
data as backup or
transfer it via a satellite link.
Conclusions/Suggestions
• Concordia to provide stable power
• Recommend a central data-backup facility
• Concordia to provide local ethernet at the Gbit level
• Need real-time environmental data (e.g. wind, ice)
• Concordia to define standards before each project produced their
own (i.e. now), e.g. computer hardware, network switches etc.
•
• Projects to provide their own dome, cabling etc.
• Projects to provide their own UPS and filter/transformer systems
• … and, finally, projects provide human-independent operations
(„the more robotic the more likely you get data“)
Antarctic Research: a European Network in Astrophysics
26.-29.3.2007 Puerto Santiago, Tenerife
SOC: A. Allan (U. Exeter), M. Ashley (UNSW, Sydney), M. Candidi (IFSI/CNR, Rome), J.-B.
Daban (LUAN, Nice), E. Fossat (LUAN, Nice), A. Herber (AWI, Bremerhaven), R. Lenzen
(MPIA, Heidelberg), E. Martin (IAC, LaLaguna), I. Ribas (IEEC, Barcelona), P. Salinari (INAF,
Firenze), K. G. Strassmeier (AIP, Potsdam, chair), J.-P. Swings (IfAG, Liege), G. Tosti (U.
Perugia)
www.aip.de/arena_robot