Robotization at DC Robotization at DC and its pre-requisitesand its pre-requisites

K.G. Strassmeier, AIP

Robotization = an integral systems- engineering approach

Language definition

„integral “ = science goal → environment → technology → → calibration process → operations model → data storage → → data transfer → analysis tools

„systems engineering“ = combines Optics, Mechanics, Electronics and Software. Optomechatronsoftics.

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

Language definition

Robotics concept of STELLA

STELLA Control System (SCS):Granzer et al. (2004), AN

Need Infrastructure !

Pre-requisites for Robotization

1. Un-interrupted and clean power supply2. System-status knowledge at any time3. System re-start procedure and hardware safe mode4. Reliable intra-networking between active components5. Environmental-status knowledge at any time6. Data flow from detector to storage computer7. Data transfer to local mass-storage medium 8. Data storage and pre-processing; back-up facility 9. 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 Projects/Observatories

• Diesel-driven generators decoupled from life-support system• backup generator• power grid

• 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 ...

• GPS signal • local 1-GB ethernet (+ switches, repeaters, fibers...)• network maintenance • backup system (e.g. micro-wave backbone)

Ad 2: Requires ...

• Small-bandwidth satellite conn. • (or) Iridum phone „dial in“

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: 2x225 MB/image Integration time: 10 secRead-out-time: 6.4 sec

with 50% safety: transfer in 5 sec, then acknowledgeRequires: 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 ortransfer 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“)

26.-29.3.2007 Puerto Santiago, Tenerife www.aip.de/arena_robot

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)

Antarctic Research: a European Network in Astrophysics