PhD Defense: Redundant Design and Adaptive Control of an Interleaved Continuum Rigid Manipulator

This past Monday I completed my PhD in Mechanical Engineering, bringing to a close my years as a student and my time at UW-Madison.  While I expect to break out parts of my research and dissertation in greater detail in the coming weeks, for now I want to post my dissertation and a recording of my presentation. Many people have contributed to my experience at Wisconsin, so I thank my parents, my advisor Mike Zinn, my committee, and many friends for making these years enjoyable and fruitful.

My dissertation (.pdf, 105MB) and abstract:

Continuum manipulator compliance enables operation in delicate environments at the cost of challenging actuation and control. In the case of catheter ablation of atrial fibrillation, the compliance of the continuum backbone lends an inherent safety to the device. This inherent safety frustrates attempts at precise, accurate, and fast control, limiting these devices to simple, static positioning tasks. This dissertation develops Interleaved Continuum-Rigid Manipulation, by which the hysteretic nonlinearities encountered in tendon-actuated continuum manipulators are compensated by discrete rigid joints located between continuum sections. The rigid joints introduce actuation redundancy, which an interleaved controller may use to avoid continuum nonlinearities and dynamic excitations, or to prefer particular configurations that may improve task accuracy, permit greater end-effector forces, or avoid environment obstacles. Two experimental systems explore the potential of these joints to 1) correct for actuation nonlinearities and enhance manipulator performance and 2) increase the manipulator’s dexterous workspace.
These experiments expose important design and control observations that were not apparent in the general robotic and continuum literature.

My presentation: slides (.pdf, 8.4MB)

 

 

A Longer View On Academic Publishing Platforms And Innovation

TLDR: Patentese values superficial bets on the future of technology and society, to the detriment of technology and society.

I’ve been watching the relationship between researchers, publishing platforms, and IP evolve with some interest. To choose some examples:

What technology will the next Amazon/Google/Facebook/Uber deploy?  Today’s unicorns consistently apply a novel assortment of known technologies to some large market beset by some inefficiency.  In the absence of oracles, the next unicorns are guessable.  If you can observe the pace of innovation in any particular field — say the number of publications per year — you quickly learn what technology sectors are interesting to academics and also receiving funding.  If you see this rate of innovation increase, that signals that something new has occurred.  And because researchers and funding agencies like to be fashionable, a quick semantic similarity analysis across the literature in that increase will give some sense of what the excitement is about.

Most researchers want to make ‘life’ better, and most people are happy to pay for a better life.  Since researchers are generally only excited by progress towards their discipline’s goals, and since those researchers inhabit the same reality as their eventual consumers, what excites researchers will probably, eventually, ideally, be valuable to society.  So, if you notice increased innovation in some sector and realize that, by the nature of that sector, growth will impact many, well that’s worth paying attention to.

Having some intuition, it’s time to place bets.  The form of the bet would differ by institution: funding agencies can target for some desired effect (say, Rep. Smith) and trolls could weight their acquisitions by maturity and potential scope (today’s trolls as amateurs).  So, such a learned-intuition technology is agnostic to the ends (as ever), but, the actors differ greatly in their ability to amass the underlying database, and in the rewards for applying it.

Who is positioned to leverage the learned-intuitions? Funding agencies are doubly disadvantaged: grant reporting is sporadic and does not approach the rigor of (generally privately-held) peer-reviewed journals, while the ends will always be subject to the shifting winds of bureaucratic debate.  (Moves toward open access, data, and analyses would remedy both of these, though they may be stymied lobbying.)  With the government’s manifest inability develop and apply new technologies, pessimism is warranted.  Certain, other entities are advantaged as this relatively cheap method can extract more value out of already-held repositories.  I picture this as a(n) hourglass, where fields of research may be analyzed (both semantically and in the author/referenced/viewer graph) to identify emerging trends.  This is the broad, upper funnel.  The observed trends may be entered into patents, where the patentese (the stilted language encountered in patents) can hide the absence of a reduced-to-practice, coherently-understood innovation.  This is the hourglass’ neck, with one ideal being a single patent that draws inspiration from many observations and thereby is able to make broad claims across products (the hourglass’ expanding lower chamber).  A form of this speculative patenting occurs in many university tech-transfer offices today, who grasp at any IP in a projected-to-be-sexy market, but is greatly improved by the intuition wrung from a large database.

The problem, the social harm, is that the standard of proof differs between the literature, patents, and the market, and so do the rewards.  Researchers, ‘the literature,’ broadly value interesting, well-posed, and thoroughly-explained experiments.  New works are valued by their novelty, by the degree to, and manner in which they solve the associated problem…and not by their sweeping claims.  Good work is not immediately and individually rewarded, but appreciated in aggregate through greater grant success and honorariums.  The market has a related interest in things that work, that solve the consumer’s problem…and little patience for those that do not.  It does not reward ideas but their execution, and there is a federal agency to restrict claims to reality (the FTC in its consumer protection role).  Between the researcher and market lie patents; on one side patents draw inspiration from disparate developments and on the other they seek to claim parentage of broad swaths of future products.  The reward is (US, typically) a 20 year monopoly over all possible renditions of the claimed idea, far beyond that which was realized during the original application.  Whereas both the literature and the market incent specificity, the patent system incents vagueness.

Combining the aggregation of the academic literature into large databases in machine-readable forms with big-data analyses can* yield patentable claims. While there are probably big-data ways of evaluating market potential for determining the risk of particular claims, I suspect researcher interest to be a good proxy. (At least in some domains, as great interest and excitement in the newest particle or complexity does not a market indicate.) I imagine the typical result to be patents like Myriad’s BRCA-1 test or the CRISPRs; things that are close to the literature dressed up in patent language. The patent application is not going to be reviewed for actual utility (as FDA does) nor is the patent examiner going to verify that the claims are possible, only that they are plausible given the state of knowledge.  As the burdens and perverse incentives (see the paper) of the examiners are widely known, entities might craft patent applications whose background summary and prior art are not representative of the literature but tilted to their benefit.  Again, it does not matter (to the applicant) whether the claimed innovation actually functions, but only that it appears plausible. The risk of discovering this (potential) impracticality is reduced by the patent thicket, where the number of granted patents is more important than their quality (courts are similarly burdened in testing the leveraged claims).

Without reforming the incentives, rewards, and norms of the (US) patent system, I fear that they will become an even larger vehicle for rent-seeking. Who’s the master of these databases, and really, the knowledge they contain? For, as I mentioned, the semantic analysis of the literature may be put to other, more socially-useful purposes. It is important to remember that the purpose of patents is “To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries;” the very advance of technology has rendered sub-optimal the current form of the patent system. I am not against patents, but I do ask that they be useful.

*an assertion I think true, whether this is possible today or tomorrow is debatable

PhD Preliminary Examination

I gave my prelim presentation this past January, recapping my work with Prof. Zinn on Interleaved Continuum-Rigid Manipulation. The presentation went well and I enjoyed the audience’s and committee’s questions, most of which centered on things that would be very fun to look at given infinite time. As I hope to graduate soon, I’ll only be able to look into a few of the most fundamental questions, saving others for later students. With that, here are links to my document and narrated slides, followed by the prelim’s abstract:

Preliminary Thesis [45MB PDF]

Slides [6.1MB PDF]

Prelim Presentation from Ben Conrad on Vimeo. (and on YouTube)

Abstract

Continuum manipulator compliance enables operation in delicate environments at the cost of challenging actuation and control. In the case of catheter ablation of atrial fibrillation, the compliance of the continuum backbone lends an inherent safety to the device. This inherent safety frustrates attempts at precise, accurate, and fast control, limiting their use to simple, static positioning tasks. This preliminary work develops Interleaved Continuum-Rigid Manipulation, by which the hysteretic nonlinearities encountered in tendon-actuated continuum manipulators are compensated by discrete rigid joints located between continuum sections. The rigid joints introduce actuation redundancy, which an interleaved controller may use to avoid continuum nonlinearities and dynamic excitations, or to prefer particular configurations that may improve task accuracy, permit greater end-effector forces, or avoid environment obstacles. Two experimental systems explore the potential of these joints to 1) correct for actuation nonlinearities and enhance manipulator performance and 2) increase the manipulator’s dexterous workspace. These experiments also expose important design and control observations that were not apparent in the general robotic and continuum literature.

Electron Beam FreeForm Fabrication — IN SPACE

In the last post I described the basics Electron Beam FreeForm Fabrication (EBF3), here’s why I’m excited about it:

Let’s walk through this process:

Metallic Refuse

Life and research aboard the ISS requires a lot of supplies and results in good amounts of waste.  This is the most expensive garbage in the world, and, due to the restricted lab and living space, includes completed experiments and spent supply ships along with the more obvious packaging, clothing, food, and other waste. Given the nature of space exploration, this waste components of this waste are known absolutely and excellent candidates for in-orbit recycling.  Used Progress and other supply ships, having arrived at station, could likely be stripped of components and structures that are not required for their reentry garbage truck function and again recycled into new components and structures.  Though accompanied by greater risk, ISS (or some other manned or unmanned station) could also serve as a destination for end-of-life satellites as the only place where there residual in-orbit material value may be captured.

Garbage, Meet Recycler

If you introduce a metal into an electric field sufficient to overcome the intermetallic bonds, those bonds will break, freeing electrically-charged ions from the donor.  This plasmification is the basis for vacuum deposition, but what if the donor is not a pure metal but rather some alloy?  What if the donor is something like the aluminized mylar found in space (-age) blankets?

The second part of this step is an external electromagnetic field, as commonly found in mass spectrometers.  If the plasma is accelerated by an electric field and then encounters a magnetic field, the ions will arc according to the strength of the field and their mass.  With the electric and magnetic fields coarsely tuned according to the known properties of the garbage, its component atoms can be sorted into atomically-pure stacks.

Sorted Feedstock

These atomically-pure stacks are highly valuable, due to their purity and location in earth orbit, as long as there is a process by which they can be made into something new.

Feedstock, Meet Printer

The same combination of electric and magnetic fields used to recycle garbage can be 3D printed into new components and structures.  By selectively introducing atomically-pure feedstock into the same electron beam used for plasmification and guiding the plasma via the same magnetic field, a part could be build layer-upon-layer.  This is essentially EBF3, though instead of a translating build platform the platform could be stationary and the beam scanned across the part by varying the magnetic fields.  (Though for alloying a translating stage or translating emitter might be required…)

3D Printed, Variable Alloy Components…In Space

3D printing metallic components in space would be a game changer; it would allow recycling of substantial fractions of today’s orbital garbage into new components that equal or rival their terrestrially-produced counterparts.  Further, the cycle described could also be applied to asteroidal and other in-space resources.  I don’t know what technology Deep Space Industries envisions…

…but I can’t see why EBF3 would not meet their needs.

Finally,

I’ve spent 500 words describing this concept, but it seems to be worth much more study.  While the individual elements of the described cycle exist terrestrially (and mass spectrometry has been used on many robotic space missions) they have not been integrated into a single apparatus.

Many questions accompany this concept; I hope to explore some of these going forward (as posts, and perhaps more formally), and, more than that, answer why MadeInSpace is on the ISS rather this…

Electron Beam FreeForm Fabrication (EBF3)

There are many cool things happening in 3D printing these days, but the technique I’m most excited about, electron beam freeform fabrication (EBF3), has received very little coverage.  So in this and following posts, I want to describe the basics of this technique and some of the cases where I think it is the ideal manufacturing technology.

Printing in plastic is easy.  Heat some PLA or ABS to 300-400F and squirt it out of a small nozzel while tracing the outlines of your part.  Alternately, selectively shine a UV light source on some UV-cure epoxy and you have a stereolithography machine.  These two techniques, finally free from patent protection, are responsible for virtually all of the media buzz in 3D printing.

While these technologies accomplish the basic aim of converting a CAD design into a dimensional prototype, few of these additively-produced prototypes can withstand loadings similar to those a traditionally-machined part (even when machined from the same plastic, let alone metal versus printed plastic).  Not every application needs this durability, but it is the greatest limitation of every 3D printer you’ve probably heard of.

Printing in metal is expensive; in contrast to the great variety of Kickstarted $300-3,000 consumer/prosumer printers, MatterFab made news this past summer with the announcement of a metal-printer targeted at $100,000.  This printer, and it’s million-dollar-plus competitors, uses a kilowatt-class laser to melt particles in a metal powder together, forming a solid part.  Depending on the scan speed, laser intensity, and material addition rate, this method (referred to as laser-engineered net shaping – LENS – and metal laser sintering) can produce fully-dense parts with material properties similar to those of cast or annealed parts.  Since melting the metallic powder depends on the relationship between the laser wavelength and intensity and the powder’s melting point and absorbtivity, machine cost and material selection are closely related.  Common configurations have difficulty producing aluminum, titanium-aluminide, tungsten, magnetic alloys, and others.   These difficulties are easily explained by considering the reflectivity of some common metals versus common laser wavelengths:

Reflectivity of common metals and common laser wavelengths. HPLD stands for high-powered laser diode. Chart courtesy Kennedy, Byrne, and Collins, 2004.
Reflectivity of common metals and common laser wavelengths. HPLD stands for high-powered laser diode. Chart courtesy Kennedy, Byrne, and Collins, 2004.

Similar to LENS, Electron Beam Freeform Fabrication (EBF3) directly melts metallic materials to form a fully dense part, though using an electron beam rather than a laser. EBF3 commonly uses a stationary electron beam and a multi-degree-of-freedom positioning system to build parts layer-by-layer. As shown below, the electron beam is focused at a particular point, melting any co-located materials. Introducing new material into this region – by a wire feeder – increases the volume of this pool. Indexing the positioning system causes the pool to move, leaving behind newly deposited material. Adding a second wire feeder enables in-pool alloying and the production of functional gradients (varying the alloy along the part). Most EBF3 systems operate inside a vacuum chamber to both prevent the surrounding environment from attenuating the electron beam, which also eliminate the prospect of part contamination.

Left: Schematic representation of electron beam freeform fabrication (EBF3), courtesy Taminger & Hafley, 2008. Right: An EBF3 machine at NASA Langley, courtesy of Bird & Hibberd, 2009.
Left: Schematic representation of electron beam freeform fabrication (EBF3), courtesy Taminger & Hafley, 2008. Right: An EBF3 machine at NASA Langley, courtesy of Bird & Hibberd, 2009.

Along with the prospect of metal-agnostic (or more so than LENS), studies from an EBF3 research group at NASA Langley indicate that resulting parts are stronger than wrought and tempered alloys:

Comparison of EBF3-produced Al 2219 to Al sheet and plate from Taminger & Hafley, 2008. ‘Typical’ refers to conventionally-produced wrought and tempered sheet and plate properties. Of note, the ‘As-deposited’ specimen has greater strength than the wrought and a T62-tempered EBF3 deposit outperforms a conventional T62 alloy.
Comparison of EBF3-produced Al 2219 to Al sheet and plate from Taminger & Hafley, 2008. ‘Typical’ refers to conventionally-produced wrought and tempered sheet and plate properties. Of note, the ‘As-deposited’ specimen has greater strength than the wrought and a T62-tempered EBF3 deposit outperforms a conventional T62 alloy.

In addition to producing parts with commendable material strength, EBF3 is a fast process. Able to trade resolution for speed, EBF3 has been demonstrated at deposition rates of 178 to 594 cm3/hr (11-36 in3/hr) in Al 2219 and 434 cm3/hr (26.5 in3/hr) in Ti-6-4 [Taminger & Hafley, 2008]. As a point of comparison, a representative laser-based system deposits at 8 to 33 cm3/hr (0.5 – 2 in3/hr) [Taminger & Hafley, 2010].  The electron beam is also more efficient at delivering energy to melt pool, at approximately 95%, than a laser process, which might see 10% efficiency due to losses in the laser, beam transmission losses, and the naturally high reflectivity of most metals [Taminger & Hafley, 2010].

According to Lori Garver (NASA Deputy Administrator through 2013), EBF3 is used in fabricating the titanium spars for use in the F-35 Joint Strike Fighter; some more mundane results are below:

Parts produced in Taminger & Hafley, 2008: a) a TI-6-4 wind tunnel model, b) a square box of Al 2219, c) an Al 2219 airfoil, d) an Al 2219 mixer nozzle, e) an Al 2219 converging/diverging nozzle, f) a Ti-6-4 guy wire fitting, g) a Ti-6-4 inlet duct, and h) a Ti-6-4 truss node.
Parts produced in Taminger & Hafley, 2008: a) a TI-6-4 wind tunnel model, b) a square box of Al 2219, c) an Al 2219 airfoil, d) an Al 2219 mixer nozzle, e) an Al 2219 converging/diverging nozzle, f) a Ti-6-4 guy wire fitting, g) a Ti-6-4 inlet duct, and h) a Ti-6-4 truss node.

The significant disadvantage of EBF3 is poorer control of the part surface quality than plastic and LENS printers. EBF3 part resolution is essentially limited by the feed wire diameter, but this diameter dependence has not been demonstrated in the literature.  Given the commercial availability of LENS techniques, the majority of the community has focused on understanding EBF3 and its unique alloying ability.  EBF3‘s selling point of printing with high strength alloys places the focus on accurate alloy production; applications demanding these alloys are sufficiently advanced (and costly) to delay interest in higher resolution.

EBF3 also requires an evacuated build environment, on the order of 1×10-4 Torr, adding an appreciable degree of complexity to any EBF3 (terrestrial) system [Taminger & Hafley, 2008].  Davé’s original 1995 description mentions that use of a high-energy electron beam (>500keV) can eliminate the need for vacuum, though such a device will be accompanied by its own complexities in generating large potentials. The literature has apparently not yet considered this variation.

Producing spars for the F35 is nice, but to me the killer application for EBF3 is not terrestrial, but in-space.  In the next post I’ll lay out why I think EBF3 is the ideal in-space manufacturing technology.

TRACLabs

After graduating in December 2010 I had 6 months to spend before starting grad school, so I went on an extended internship with TRACLabs in Houston, TX.  TRACLabs is a small company that does automation and robotics research and development work for NASA and the Defense Department.

My work centered on developing and using TRACBot, a powered wheelchair – based development robot.  During the spring and summer Patrick, Mars, Bryn, and I significantly upgraded TRACBot from

TRACBot outside
TRACBot outside

to

I worked on a number of projects over the spring and summer, here are some highlight videos:

Beat-Based Gestures with Brown University

Leader Following

Wounded Soldier Extraction

And some pictures:

Laser Building in Germany

Intro

Just arrived from the airport.
Just arrived from the airport.

As I’ve said elsewhere, I’m heading to Germany to complete a sensor system I’ve been working on for the past year with Prof. Scott Sanders, supported by LaVision, GmbH. I’ve covered the project-specific details and have a couple documents here. I fly out of Chicago this Saturday (5/30) and will arrive in Frankfurt on Sunday morning. Monday (6/1) is a national holiday, Whit Monday, so I’ll spend Sunday and part of Monday exploring Frankfurt before taking a train to Göttingen.

Once in Göttingen, I’ll build the sensor and explain the analysis code. LaVision will then take the prototype and reduce it to a smaller form factor and optimize its function. I’ll return to Frankfurt next Tuesday, 6/9, and will arrive back in Madison Wednesday afternoon.

I took a bunch of pictures and posted them to Flikr; a few are included in the description below.

Trip to Germany

Saturday morning I took a Van Galder bus to Chicago and checked into my flight to Newark, NJ. There was no one else in my row on the Boeing 757 and I enjoyed flying around New York and flying over the Statue of Liberty and Central Park. I arrived around 4:00 and expected to have a two hour layover before heading to Germany via Air India. Since I was switching airlines I needed to check into Air India, whereupon my layover disappeared.

My flight from Newark to Frankfurt was only the first leg of an Air India flight to India. Since New York is a moderately large metropolis and India is a bit far away, flights are not commonly offered. As such, the check-in line was quite crowded with families traveling or returning to India. I spent ~45 mins in the check-in, after ensuring that I did not need to transfer my luggage from my Chicago flight.

Now, Newark is a bit of a weird airport in that each terminal has its own security check in; there is no secured passage between the terminals. As such, I rejoined my fellow passengers in the security line for another twenty minutes. Throughout check-in and security, I got the impression that Air India paid less for its berthing and terminal space than all of the other airlines. Things just didn’t flow as smoothly as one would expect in a major airport. Perhaps that’s how they offer a $360 roundtrip flight from Chicago to Frankfurt…

I had hoped to eat supper but only had time to grab chips, a muffin, a croissant, and a soda before boarding. Since I was departing in Frankfurt, while the plane refueled, my seat assignment was changed to an exit row, giving me more room for my right leg but less for my left (the door opening mechanism protrudes from the cabin wall). The flight itself was pretty uneventful and authentically Indian. I chose trout for my supper and had a croissant for breakfast.

We arrived at the Frankfurt am Main (on the Main river) Flughafen at 8 am Sunday (6/1), right on schedule. It was a simple matter to find my luggage and a train to the Hauptbanhof (train station). I got a little confused by their train station naming and nearly got off at the stadium in SW Frankfurt, but maps stored on my phone prevailed — not enough buildings, tracks, or people.

Reaching the station, I was impressed. I knew that trains were widely used in Europe – and planned to use them for all transportation within Germany – but it was not until I saw the Hauptbanhof that I began to realize their national importance. I think that an institution’s physical presence is a good indicator of its regional and national importance. If it is impressive then the people feel it is a good use of public funds; if it also functional, then it shows that the institution understands its purpose and the needs of its users. Trains are continuously arriving and departing, shops are open for any travel need, announcements are multi-lingual, and people are hustling about. Taken together, the importance of the rail system to Germany’s infrastructure is clear.

McDonalds, Burger King, Pizza Hut, and Subway are everywhere, often within blocks of each other. Soda is pretty scarce, Coke is commonly available and Sprite and Pepsi are rare, but I found no others. Instead, Germans seem to prefer water and apple juice with gas (carbonated / seltzer).
McDonalds, Burger King, Pizza Hut, and Subway are everywhere, often within blocks of each other. Soda is pretty scarce, Coke is commonly available and Sprite and Pepsi are rare, but I found no others. Instead, Germans seem to prefer water and apple juice with gas (carbonated / seltzer).

Once the cool factor passed, I looked for some food. Thankfully (?), Germany is overrun with McDonalds, Burger Kings, Pizza Huts, and Subways. I was hungry for a burger (my supper plan for Newark) and went to Burger King at ~9:30. Since I don’t know an ounce of German, I had one English/German travel guide & dictionary in my pocket and a different version in my backpack. I had saved a map of the route between the train station and hotel on my phone and tried to check in.

Frankfurt – 6/1

map

I reached my hotel at 10:30 but my room wasn’t ready, since check-in started at 15:00. I checked my suitcase with the front desk and picked up some more complete city maps. With maps and dictionary in hand, I went for a walk around the city.

When I was setting up the trip I had noticed a park relatively near my hotel and headed that direction. Consulting my maps, I saw that the park actually extended around the entire city center in a three mile semi-circle, beginning and ending at the river. Camera in hand I began. It felt real good to stretch the legs and the new scenery kept me awake, since I had only slept for three hours during the flight and needed to absorb the seven hour differential.

The park was cool and fairly busy for a Sunday morning. Biking is quite common (similar to Madison, but the roads are built more with bikers in mind and for smaller cars) and most people were getting some exercise. There was quite a lot a vegetation and these big trees which I don’t recall seeing in America. Anyway, see the Flickr tour for more. I kept walking in the park till I reached the river and walked over some downtown bridges and along the waterfront. I tried to see St. Bartholomeus’ Cathedral but they were holding service when I stopped by. It was about 13:00 and I headed back to the hotel, having circumnavigated Frankfurt. My room was ready and once I sat down the rest of the afternoon and evening were lost.

Frankfurt -> Göttingen – 6/2

I slept well and was ready to go by ~9. I would be heading to Göttingen in the afternoon and wanted to explore Frankfurt a bit more. I walked through the heart of Frankfurt but most of the shops were closed I went through the Zeil, a cool downtown mall with an innovative roof (you may have heard of it…) and continued towards the river. Frankfrut was holding a festival, Turnfest, along the river and in a historic downtown square. While there I didn’t know what was being celebrated/remembered, but apparently Turnfest is the world’s largest leisure sports and competition festival. Most of the activity took place in the city fairgrounds so what I saw was a small part of the festival, but cool nonetheless. I toured the Paulschirche (St. Paul’s Church and German seat of government in the 1800s) and a historic building with lots of flags. There was a stage set up in a public square near the Paulschirche and a band was playing. It sounded cool and as I continued to walk through I saw what appeared to be church service leaflets. By this point it was about 10 and was turning into a beautiful, mid-70s day. It was all in German so I started back towards the hotel, needing to check out of the hotel by 11.

Picking up my suitcase I went to the station and purchased an InterCity Express (ICE) ticket to Göttingen. I had a simple salami, cheese, and hard-boiled egg sandwich and Coke while waiting for my train. Göttingen is about two hours north of Frankfurt by train, in the middle of the country. The train was pretty nice (leagues above Amtrak & moving twice as fast) but I must’ve missed something when purchasing the ticket, as I twice had to give up my seat to someone who reserved it. I’m still not sure how or why they reserved the seat but was a little annoyed to be bumped by someone getting on two stops after Frankfurt, especially since there were open seats…

Heading up to Göttingen, nice country
Heading up to Göttingen, nice country

Anyway, the German country side is nice with lots of rolling hills, occasional villages, and a good mix of forest and farmland, quite similar to Wisconsin. From a distance the only difference is architectural, with Germans preferring closely-spaced, clay-tiled houses to American suburban and rural sprawl.

Probably a third of the size of Frankfurt, Göttingen also has a quaint, bustling city center contained within the old city wall. I searched the station for a good map but finding none, started toward my hotel relying on my cellphone map. I stayed the week in the Hotel Kasseler Hof, chosen by my hosts for its close proximity to the city center. The room was simple; the double bed was indeed two, single mattresses placed side by side with separate sheets and covers for each…the Ramada was the same way. The breakfast was much more wholesome (bread, sandwich meats, fruit, baked green bean bundles wrapped in bacon…) than most continental breakfasts in America. While I’m on food, Coke (and Pepsi) taste sweeter in Germany, possibly due to the predominance of carbonated water (with gas). I didn’t get used to this and you can imagine my surprise when my apple juice was also carbonated.

When in Frankfurt I had some difficulties with my laptop’s AC power adapter which I attributed to my international adapter. Reaching Göttingen, I verified my international adapter and realized that the power adapter had indeed been broken in flight. Hoping for a bad solder weld or a broken wire, I took the adapter apart (keychain leatherman…) but to no avail. Without my laptop/internet, I picked up a map from the front desk and took a walk about the city. Since it was still Whit Monday, few shops were open but the weather was nice and ice cream made a good supper.

LaVision – 6/3-5

I met the project manager, Thomas, at 9 on Tuesday morning and went to LaVision to begin work. In general, LaVision takes optical sensing systems and integrates them into simple and stable laboratory instruments. In the context of my project, LaVision desires to reduce the source/sensor complexity and integrate the components into simple-to-connect containers so that a non-spectroscopist can use the sensor. They have a nice balance between lab and office space, allowing the various groups to develop and work closely with new sensor systems.

Tuesday through Thursday I spent assembling the laser of parts we had preordered. Thankfully nothing was broken outright and of the two issues that appeared, one is largely solved and we have some ideas for the second. The main purpose for the trip was to bring the project team up to speed on the various component choices in the light source and for me to share some of the operation characteristics of the system. Friday we went over the data acquisition and temeprature-finding routines; this currently consists of four independent steps which will hopefully be rolled into one, real-time temperature finding routine. This was the most difficult part as I have comparatively little experience in molecular absorption and had not recently thought through the various operations in the temperature finding and simulation codes. Things came together and I believe I answered their immediate questions (they all speak English well). I’m sure that there will be more questions as development continues but I believe that the broad objectives are well understood.

LaVision also had an HP AC adapter so I had power and internet whilst at their facility, but the hotel internet proved intermittent. Skype was especially encumbered, it seemed as if the hotel had a bandwidth limit and any transatlantic video chat quickly hit that limit. This system failure was less than graceful as it prevented me from logging on during the next two days, eliminating any personal internet usage (it’d be a bit much to be posting to Flikr/facebook while at LaVision).

Internet issues aside, Thomas took me out for supper and a beer almost every night (and never to McDonalds/BK/Subway) and I got to learn a bit more about Göttingen and life in Germany.

 

Berlin – 6/7

Arriving in Berlin
Arriving in Berlin

I took Saturday easy but planned a trip to Berlin for Sunday. The Deutsche Bahn has a nice weekend program, an unlimited number of train rides for €37. Leaving Göttingen at 6:30, I took three regional trains up to Berlin. There’s a lot of history in Germany and I enjoyed traveling through the former East Germany on my way to Berlin. Perhaps it was the route choice, but most of the small towns we went through seemed to have stopped growing. In many ways it is the same as what’s happening in northern Wisconsin / the UP; where younger generations are leaving their elders for larger cities and modern convenience. Prosperity returned as we approached Berlin, arriving at the Hauptbanhof at 13:45.

map

After taking pictures of the terminal, I stopped at Pizza Hut for lunch. Finishing, I headed southeast, across the Spree River and past the Marie-Elisabeth-Lueders-Haus (part of the parliament complex). Pausing for a few pictures at the Reichstag, the traditional seat of parliament, I reached the Brandenburg gate and spent a little while reading the gate’s history. There were music stages on both sides of the gate and lots of people around. Vendors lined the first half mile of the Straße des 17. Juni (commemorating “the uprising of the East Berliners on 17 June, 1953” – wikipedia) and I slowly made my way through the stands, heading west.

Nearing the Siegessäule...it wasn't exceptionally bright, so I'm not sure why this looks painful...
Nearing the Siegessäule…it wasn’t exceptionally bright, so I’m not sure why this looks painful…

I walked through parts of the Tiergarten and happened upon a concert at the Carillon. At 60m, the Siegessäule (Berlin Victory Column) dominates the Tiergarten skyline, so I continued that direction. Since it was still mid afternoon, I bought a ticket and climbed up the column through an interior stairwell. About 5m up, an intericate mosaic covers the central column and encircled by large, red granite columns; see the photostream for close ups. Continuing upward, the circular stairway becomes more like a ladder, especially when passing other visitors. I reached the top and took in the surroundings, appreciating the extent of the Tiergarten and all the traffic/activity. It was about 16:00, so I finished looking around and descended the column.

I was now southwest of the train station, so I walked along the Spree and past the Bellevue Palace. I couldn’t tour the building or see any interior pictures since it is the President’s residence, but both the exterior and extent of the building make it worthy of ‘palace.’ Continuing along the Spree, I passed the House of World Cultures and the Chancellery. As is evident from the pictures, both the Chancellery and Parliament are impressive buildings; they face each other across a broad square to the north of the Tiergarten.

My train departed at 17:10 so I grabbed a danish pastry and a soda for supper. I had forgotten my book at the hotel and bought a German newspaper that recapped May news stories in English. This was written from the German perspective and included a number of opinion pieces, I enjoyed reading the authors’ take on events in Germany and America, as well as the special on Indian/Pakistani relations.

My return trip stopped in Madeburg, Braunschweig and Kreiensen, a west-then-south route. I had an hour in Barunschweig and stopped at a Subway for some cookies (~20:00) and went on a short walk near the station. The city also had a large downtown park and, had it been earlier in the day, I would have walked through. Returning to the station I found that my train to Kreiensen was delayed 15 minutes, adding a little anxiety to the trip since I originally had a 20 minute layover. After hurrying to the Kreiensen-Göttingen gate, I found that that train was also delayed an indeterminate amount of time. About 30 minutes later the train came and I arrived in Göttingen at 00:30 Monday morning. All in all, it was a pretty condensed walk around Berlin, but an enjoyable use of my Sunday.

LaVision – 6/8-9

After too little sleep and some surprise at my weekend trip (on the part of my hosts at LaVision), we prepared a simple flame test for the sensor. We were unable to independently verify the flame’s temperature, but I was able to show how the acquisition and analysis pieces came together and get some preliminary temperatures by the end of Monday. I spent Tuesday morning summarizing the sensor operation, step-by-step and concluded the workday with a final demonstration.

To complete my German experience, Thomas took me to the Paulaner for some Bavarian food Monday night. My main dish was three meats: Leberkäse (liver-cheese that contained neither…sort of like ground ham), Weißwurst (a white sausage), and some other kind of sausage. In with these were some very good potatoes, lots of Sauerkraut, and Weißbier (light, almost sweet) to wash it down. It was a very good, filling, and greasy meal.

An aside: I gave you this amount of detail since many of you know that I have simpler tastes than most. Suffice it to say, I did not starve while in Germany and ate very similar meals to what I do in the states (calling it American would be improper, since the only truly American dish is a burger). If anything, the places that I visited had less food diversity, lacking Mexican and Chinese restaurants.

I caught a 17:20 ICE train and was in Frankfurt by 19:40, whereupon I checked back into the Ramada. It was still a bit early so I headed out towards downtown for some supper and a store or two. I eventually settled on ice cream (again, I’m not sure why it tasted so good for supper…) but found that every store closed at 20:00. Exactly. It was still light out and a good amount of people were walking around, but by 20:05 most lights were out and employees headed home.

Return Flight – 6/10

My flight departed Frankfurt at 8:05, so I was up at 5:00 to catch a 6:00 train to the airport. Reaching the Hauptbanhof, I prevailed against the ticket machine and searched for my train. My first choice train was departing gate 103 so I searched the station but only found gates 1-25. After 103 supposedly departed, I checked the route tables and realized that #22 would take me to the airport, departing in 5 minutes. I boarded the train and was a bit discomforted by my fellow passengers’ lack of suitcases; as the train left the station the train began turning northwest and I watched the southwest track I though I was on recede from view… Getting off at the first stop in northwest Frankfurt, I searched for another train back to the Hauptbanhof. Upon returning, our train went below ground and I emerged from gate 103, one of the subterranean gates that I saw no indication of in the main terminal. Studying the route information for the third time, I realized that my #22 train to the airport only ran on Sundays and, enlightened, found a train that would take me to the airport. This train departed at 6:38 for arrival at the airport by 6:52. So, where I had intended to have two hours for check in I now had an hour.

Thankfully, most passengers were already on the Air India flight from Frankfurt to Newark (having originated in India) and the check-in and security lines were relatively short. I reached the plane ten minutes before takeoff but was unable to get any snacks or fill my water bottle (empty for security). It was cloudy beneath us for the entire trip back, making it very bright outside the plane which helped to keep me awake. We arrived in Newark right on time but my two hour layover was consumed retrieving my suitcase and checking into my American Airlines flight to Chicago. As before, I had 20 minutes before boarding, during which I found a cream cheese danish and finally filled my water bottle. I intended to take the VanGalder bus back to Madison but was a little worried about the timing; the flight was scheduled to arrive at 13:50 and the bus was departing at 14:30. If the baggage claim was quick it’d work out, if it was slow or we were otherwise delayed in the air I’d have to wait for the 15:30 bus and not arrive in Madison till 19:00. Thankfully (and I was) things worked out and I made the early bus to Madison.

Back in Madison, I met my mom for supper at the Nitty before returning to my apartment to pack for Florida.
So ends my trip to Germany. To summarize, I read three books, two magazines, and a newspaper, used five German words, built a laser, took my AC adapter apart, ate and drank, took lots of pictures, walked over a mile in four German cities, rode trains for 15 hours, did some LabVIEW coding, saw historical places, and had a great time. I got quite a lot out of this trip and now better understand and appreciate commercial research and development. Moreover, I found that I could go to a new country and get around reasonably well. Knowing German would have made the trip much more enjoyable and I’d have been able to avert a few travel hiccups, but I thoroughly enjoyed this experience.

Thanks to my host LaVision, especially Thomas Berg and Olaf Thiele.

 

ZeroG Team

I enjoyed developing three experiments with the ZeroG Team during my undergrad at UW-Madison.  Participating in NASA’s Reduced Gravity Student Flight Opportunities Program, I joined students from across the nation in designing experiments to be performed in a microgravity environment. Over three years, we submitted three research proposals, and NASA selected two of these experiments for investigation aboard the DC-9B Weightless Wonder.  This plane achieves microgravity (zero-g) by flying a parabolic path, during which the plane, occupants, and experiments experience zero gravity for 30 seconds.  My flights capped 11 consecutive years of UW experiments in this program; see below for descriptions.

Experiment Summaries:

2006-7: Measuring Capillary Forces in Microgravity

Our team designed an experiment to research capillary action in microgravity.  Capillary action is the phenomena that allows plants to transport liquid from their roots up to the highest branches.  In contrast to terrestrial applications, microgravity fluid systems cannot rely on gravity to collect fluids; instead the absence of gravity often ‘allows’ fluids to get trapped in the corners of tanks far from the tank exit.  In these cases, the fluid cannot be drawn out of the tank, and though unspent, is useless.  To better understand this situation, this experiment measured the flow velocities of two liquids as they flowed up five differently-angled surfaces (see video, below).  These velocities are a function of the fluid properties and the surface geometry; interpreting our results will guide fluid system design to avoid trapped-fluid scenarios.  This research can also be applied to transporting fluids in space without pumping.

Presentation

2007 – Capillary Action – John & Ben from Ben Conrad on Vimeo.

2007-8: Spray Cooling in Microgravity

In this experiment we researched the effectiveness of spray cooling in microgravity.  Spray cooling uses an array of nozzles  to create a turbulent fluid mixture on some hot device for the purpose of cooling that device.  The hot device may be a microprocessor or laser diode, where instead of a heat sink and/or fan (as you find in your computer), we’re using a liquid cooling loop with fluid sprays that impinge on the heated surface.  Whereas the amount of energy that heat sinks can dissipate limited by the velocity and ‘energy absorption capability’ of air, using a liquid provides a substantially greater capability.  A simple schematic of the test chamber is below, as are our documents.  This research was presented at the 2009 Space, Propulsion, and Energy Sciences International Forum in Huntsville, AL.

Spray Cooling overview

SPESIF Presentation

SPESIF Proceedings Paper

2008-9: Continued Investigation of Linear Spray Cooling

Our previous spray cooling experiment answered some questions but motivate a number of others.  In my Junior year we proposed a new array design and a more thorough characterization of spray cooling in microgravity.  The new array design was precisely machined from a single piece of aluminum, as opposed to the array of tubes used in previous linear spray arrays.  Unfortunately, NASA’s support was reduced by 2/3rds and we were not selected to fly this experiment.

The new array concept:

And result:

The machined array with visible spray holes.
The machined array with visible spray holes.

Previous Years:

As mentioned, UW has been active in this program for a number of years; here are some of the materials I’ve collected which document our research.

2003: REDUCED GRAVITY AEROGEL FORMATION:

The Effects of Gravity on the Structure and Chemistry of Mesoscopic Particles in Sol-Gel Systems and the Subsequent Effects on the Structural and Optical Properties of Derived Aerogels

2004: DIRECT SYNTHESIS OF AEROGEL FROMSUPERCRITICAL FLUID:

A New One-Step Process for Weightless Aerogel Production and a Novel Method for Supercritical Fluid Analysis

2005: Long Duration Fluorescence Imaging of the Richtmyer-Meshkov Fluid Instability

2006: Dynamic Fluid Flow Due to Capillary Forces in Microgravity