2007/07/27

The "brains" of hubo are this little PC: A mini-ITX board running an 800MHz Pentium-III. Power is drawn from the distribution board shown below, which can run from any DC source.
The hubo computer runs Windows XP; besides being a familiar environment, this feature makes it easy to connect to (USB, serial), move data, and debug with a keyboard and mouse.



These parts make up the testing station. Motors, controllers, IMU's and force sensors interface just like they would on a normal hubo. The 2 small wires (yellow and black) connecting to the ITX board are the CAN interface, which connects the computer to all the peripherals in the system. This begs the question, what is a CAN and why is it used? A good technical summary can be found here (wikipedia). Practically, the advantages are clear: A CAN bus allows many different compatible devices to communicate over the same data lines. Each transmission packet has an overhead of about 6 bytes, and can transmit 0-8 bytes. The extensive header information gives each packet a unique encoding. Devices on the line can then be programmed only to receive or transmit data with a certain address. Wiring topology is thus determined by software, rather than hardware, making it easy to add/change sensors and drivers.

2007/07/11

An arm and a leg

The left leg of the Hubo is a sophisticated mix of art, engineering and subtle cleverness. The leg has a total of 6 DOF: 3 in the hip, one at the knee, and two at the ankle. These movements allow the Hubo to have almost human leg articulation. Missing from this picture are the stacks of motor driver boards which power the joints.

The design is a compromise between machining simplicity and compactness. In less critical areas like the leg structure, relatively simple machined plates support all of the parts. In areas such the hip joint (right) and ankle joint(below), the opposite is true.

The hip joint design bypasses belts and pulleys seen on the knee and ankle, and places the servo inside the joint. It attaches directly to the harmonic drive (the end of the motor and encoder is visible in the picture).

The ankle joint combines 2 axes as well, but without resorting to the internal drive arrangement in the hip. Instead, a shaft connects the drive belt/pulley from the motor to the drive on the other side of the joint. The lower belt and motor seen on the assembled leg drives the other joint, which turns on the bearing visible to the left.

The arm (left) is a good example of design with inverse kinematics in mind. A human shoulder, for example, is a ball joint, with muscles attached to pull in various directions. While this allows 1 joint surface to do the work of 3, and simplifies the mechanism, it complicates the control problem immensely. With 3 axes working in parallel, there is no unique series of motions for the muscles to move the arm through a given path.


The Hubo arm uses a series arrangement of joint axes as shown. The first rotates the whole arm, the second swings the arm, and the last rotates the arm around this new axis. since all 3 axes intersect, it acts like a single joint. Since the angular velocity between successive bodies is simple, the inverse kinematics can be easily written.

Each of the shoulder joints, as well as the elbow joint use a sophisticated internal-servo design to save space. Shown to the right is an exploded view of all the parts that make up one joint. the servo attaches to a small harmonic drive body, which then meshes with a gear inside the body of the joint. The 2 bearings allow the motor and inside of the harmonic drive to turn freely wrt the outside. This arrangement allows the outside to turn at a greatly reduced speed wrt the inside.

2007/07/09

Starting from scratch - Electronics

The first 2 weeks here have been all about learning the basics of HUBO's construction.
My first lesson was to build a universal F2808 DSP board that the lab uses for microcontroller applications. This small and relatively simple board has all the challenges of proper soldering. Aligning the 2808 chip took 3 or 4 tries, as the slightest misalignment could make very small solder shorts. While the SMD resistors are labeled with a tiny code, the capacitors are differentiable only by size and color. The same size and color chip can be 2 or 3 orders of magnitude difference; if the wrong one is soldered on, it's almost impossible to diagnose afterwards.

The A/D board I built next functioned properly, though this time I had to contend with power components. The large copper area connecting to the DC/DC converter dissipated heat, making it tough to get a clean contact.


Next up was soldering the motor controller board. Lacking PSPICE, I designed a simple Excel sheet to account for all the components off of the schematic. I wrote a few formulas to convert component values to part numbers, which could then be sorted. Soldering all of one component at a time ensured that I missed none, and that only one kind of identical-looking part would be on the table at a time. For the amplifier, a neat little trick to get the MOSFETs to line up properly was to bolt them all to the heatsink first.








Other accomplishments:
  • Obtained copy of HUBO dynamic walking PhD thesis by Dr. Jung-Yup Kim
  • wrote a brief MATLAB simulation of a lab project: the pneumatic pogo-stick
  • Photo tour of important buildings in KAIST
  • Took a photographic sequence showing major steps of leg and arm assembly
  • Rebuilt 2 broken harmonic drives; learned assembly/repair technique for similar drives located throughout the chassis.
  • Assembled a DSP board and IMU A/D board from scratch
  • Assembled a complete motor controller set (controller and amplifier)

2007/06/28

Workspace and tools


The main parts bins. For anyone who might be planning a lab in the near future, this is the example to follow. It's hard to see in the pictures, but there is a stock of every part you could ever actually use. Furthermore, all the part bins are labeled, sorted, and logically arranged.

The soldering station where I work is well equipped, if unremarkable. All of the circuit boards, from IMU to motor controller, are custom. As such, they have 10's of different blanks in stock, as well as enough solder to plumb a city. In-house technicians do the majority of the assembly (both mechanical and electrical parts), freeing up some of the students time to focus on design and experiment. The sheer volume of components in even 1 HUBO necessitates this arrangement.


Unfortunately, SMD components are a pain to both store and use. There are 5 or 6 blue trays devoted to standard size resistors, capacitors, LED's, and ICs. Due to the lack of desk space, however, you have to keep shuffling the trays to find what you need. A better approach for common boards is to fill the tray with all the parts necessary for that board. That way, assuming someone keeps inventory, you can work quickly and efficiently.

Even with the inventory on hand, assembling a board is laborious. To properly solder a microprocessor, for instance, you have to carefully line up all of the pins, tack a few in place without disturbing the chip, then heat and solder the rest. Since there are no flux pens, they coat all of the pins in an unsightly wad of solder, and remove the extra with the iron and a lot of paste flux. You get a clean joint, though you pay the price in harsh headache from the fumes. Small components like transistors, caps, and resistors are much simpler, but you still have to properly solder every joint, which means close inspection, eyestrain and...you guessed it...pounding headache after an hour or so.

The technicians make production possible; without them, students would spend hours assembling and checking PCBs. Even more so than HUBO, DASL can't afford that tradeoff without technicians. While we must have the ability to quickly repair and refurbish a damaged board, we still need to buy finished boards whenever possible to save time.

The part to the left is the perfect example of why you need the right tool for the job. To disassemble this harmonic drive, I had to remove the sun gear deep in the body. 6 heavily thread-locked cap screws held it in place. Lacking T-handle hex drivers, the technician suggested using the ball-end allen key. I couldn't communicate my doubt, since he spoke little English, but he demonstrated by removing 4 of the screws without incident. When he torqued the remaining two, however, the heads stripped. My satisfaction was brief, though, since now I had to remove two partially stripped screws from a very expensive part. After finding a bench grinder, I ground the ball off an old key. In that time, he had painstakingly drilled and chipped out one of the screws. The second one popped loose after a nervous twist of my modified key. Simply having a $30 set of T-handle hex drivers would have saved the fuss and the subsequent retapping of damaged threads.

2007/06/27

Life at the lab (in pictures)



This is my office space, and a shot of the wall jacks that everything connects to. Despite the goofy appearance of the sockets, they make much more sense. The structure makes the plug more secure when it's plugged in, and the round pins are harder to bend.



Chairs in Korea are ridiculously comfortable, and mine is no different. American chairs feel like park benches by comparison.


The living space: bed, shower, washroom, kitchen, microwave, TV...It's like a college apartment with a commute of about 10 feet. Unfortunately, that washing machine takes 3-4 hours to wash a small load, and doesn't fully dry heavy things like pants. Still, it's way better than nothing.



Each bag contains 100+ packets of instant coffee mix. Though I'm sure the coffee snobs would turn up their noses, the stuff is surprisingly good. The brown sugar is about a year old.

2007/06/26

First day at KAIST (6-19)

We visited Hyundai Heavy Industries today, where they presented yet another video (a better one, though). Their shipbuilding operations are world class, and we could see many tankers and cargo ships being assembled from our bus tour. They had a cute little gimmick where they made an industrial robot "dance" to a midi version of Livin' la Vida Loca. Random, yes, but they're Hyundai.

We finally managed to finish The King and The Clown on the bus ride. Without spoiling too much of the plot, it's a story of two minstrels who play for a Joseon king. Due to their "treasonous" material, they are forced by a court to either make the king laugh, or die. Laugh he does, and the king takes them on as part of the court. A lot of executions ensue; it's worth seeing if you can find it.

At the Taejon toll gate, I met with 2 students from the HUBO lab. Since my dorm wouldn't be ready until Friday night, I would use the sleeping area in the lab. This rooms was outfitted with a double shower, AC, an LCD TV, and personal lockers. The complete lack of windows and other light-leaking cracks means that it can be made very dark and quiet at night. As such, it's ideal for sleeping as much as one's body needs. It would be my home for the next 5 days.

A bit of structural change to come: my updates from now on will be mostly particular topics, not necessarily in strict chronological order.

Industry tour

Over the next 1.3 days, we visited 3 industrial sites that are the pride of modern Korean Industry. The POSCO steel plant in Pohang was our first stop. Some of the staff at the main office warmly greeted us at the door, leading us to a presentation room to deliver...an introductory video! My eyes were rolling like someone had let go of a window shade.

The model of the plant they showed us next was accurate and detailed. LEDs indicated which parts performed basic smelting, casting, steelmaking, and rolling. Our tour took us around most of the process by bus, but we were allowed to see the rolling mills in person. Even from 100 ft. away, we could feel the heat from the red-hot ingot as it passed through the mills. The jet of hot steam as coolant water poured on the ingot was almost deafening.

After we left for the nuclear power plant, Julie had the idea (bless her heart) to stop at the beach for a quick break. Within 10 minutes:
  • Jon and Margie got soaked up to the knees due to a wave
  • I responded to an unprovoked splash
  • The ensuing skirmish ended in stalemate due to MAD of each other's shoes
At the nuclear plant, Erica translated for the first part of the tour, explaining how the HWR worked. We even got to see Chernekov radiation first hand, as they deposited spent fuel in the holding tank. Oh, and they also showed us a video. I hate management speak so much. here's just a few of the meaningless terms they threw around in these videos:
  1. 'Future-oriented management' - Duh...any other kind of management is known as mismanagement.
  2. 'Strategic development initiatives' - as opposed to 'arbitrary development'? Why is this news? Did they just abandon plans for a sticker factory or something?
  3. 'Customer-oriented company' - yeah, and the other kind of company is called 'bankrupt'
  4. 'value-added' - buy raw materials cheap, make something with them, sell result at a higher price...otherwise known as the basis for every industry ever. Again, why is that novel enough to mention in a 5 minute pitch?
I don't understand who this sort of jargon is supposed to impress, and I'm saddened that such American bullshit has been successfully exported.

The evening ended on a high note, since Mr. Kilsu Park generously sponsored a round of Noraebong at the hotel. After more drinking in front of the hotel, some of us visited a 'foreigners-only' casino. John's winnings bought some expensive liquor for this who played, while the rest of us ended up heading back early to pack for the morning departure.

Sunday, sunday, SUNNNNDAAAYY

It was cultural tour day, which meant lots of walking through woods & mountains to see ancient Buddhist buildings. The beauty is better expressed in all the pictures taken, than in a mediocre description of the scene. Suffice to say, it was quite a change from the bustle and density of the city.

The nightlife was much more serene than the previous night. After a pleasant catered dinner, a bunch of us decided to try the local sauna. "Hey guys, guess what I brought! More dudes!" Ancient Rome knew what was up when it came to public bathing; it's too bad the desegregation has not spread. I was disappointed, but then I can't help it if I'm progressive. The baths themselves were very relaxing, and before too long we could go from an 80C steam room to a 15C cold bath with little discomfort. As John commented (and I would experimentally confirm later), it would be a perfect hangover remedy.

Nights in Kyeongju to date: 2
Nights spent at least in part drinking in front of a convenience store: 2

Final thought: Color-cycling LED arrays in concrete tiles are ingenious, and will probably make their way into my bathroom floor one day.

2007/06/25

Saturday! (6-20)

We took a bus to the Korean Folk village on the way to Kyeongju. A collection of traditional houses and workshops, it illustrated how the ancient Korean farmers lived. The various photo albums of this trip document it extensively, so I'll I need to mention is how cool the performing art was. The traditional dancers had streamers attached to a ball joint on their hats, so that careful neck movements would whirl it around.
A pair of acrobatic girls used a large seesaw to propel each other 10+ ft. into the air, giving them just enough time to do mid air splits, twists, even back flips.









The tightrope walker was even more impressive, since all he used for balance was the thrust from a fan. He could drop from the rope, bounce off off what I hope was not his balls, and step gingerly back on without losing a beat.

Following lunch, we watched "200 lb beauty", about a 200 lb singer who pursues extensive plastic surgery to gain public acceptance. It deals with how fat/ugly people are treated unfairly in society, although it fell into the trap that these movies always do by having the ugly-but-talented/kind character fall in love with the attractive+decent-but-not-extraordinary-personality character. Physical attraction is still at work here, but it's just one sided (pre-surgery, that is). The song "Ave Maria" sung halfway through the movie is probably the most memorable part. Certain members of our group still spontaneously break out with a loud MARIA!! AVE MARIA!!

Our dinner at the hotel buffet was perfectly timed; a concert for a convention of English tutors was going on, featuring a group of 4 girls that sang and played electronic instruments. It was quite a show. Of course, after a little boozing up at the Friendly Fresh outside our hotel, we put on our own little show at the local Noraebong.















It was 80's night, for the soon-to-be senior citizens of our group. We were 2 denim skirts and several scrunchies away from a "Saved by the Bell" episode, but everyone had an awesome time. The girls again showed real vocal talent, while the guys made up for it with volume and stamina. I discovered my preference for the baritone-bass range after shredding my vocal cords on "Billie Jean" (use your imagination, I've learned my lesson). With a few exceptions, everyone had at least one song they liked.

Still hungry for party, a select few of us ventured out after a brief reboozing to find the elusive Black Club, which turned out to be closed. Salvation was ours in the form of the aptly named "Night" Club, which kindly offered to fire up the DJ booth again just for us. The dance floor was sticky (and later wet with beer...Brian), but we all danced ourselves to tiredness.

O Day 4


Language lesson day! We divided ourselves into 2 groups: those who could read, and those who couldn't. I chose the advanced group under the delusion that I could read, though the days' classes would prove otherwise. And here she is, our beautiful, friendly, and knowledgeable Korean teacher, Ms. Yeon Jeong Kim (left). The morning was a long and intense practice of basic phrases, questions, numbers, and simple bits of conversation like names, dates, times, etc. Having to read the question off the board in real-time proved to be my downfall, since I could read at about .2 syllables /second. Still, she was very helpful and encouraging when we struggled. We left for lunch with a familiarity, if not a command, of the morning's lessons.

Lunch was at Bennigan's (insert Butters joke here). The one thing Bennigan's does right is ribs, but I foolishly decided to be adventurous. I still don't understand how they made a chop 'steak' taste like cheap fish, and I'm not sure I want to. Lesson: When in Korea, eat what the Koreans eat.

The afternoon lesson was easier, since we studied mostly vocabulary. After learning body parts, we learned a cute Korean version of "head, shoulders, knees, and toes". The Korean version also quiets children by design, including a little "shh" at the end. We then learned 아리랑 (Arirang), in which a dumped woman still loves her husband, and implores him to come back. It's sad and sweet. It also inspires national pride, somewhat like "Auld Lang Syne" without the confetti.


Our dinner was at a local Korean restaurant, where we went all out on the grilled meats. We had the traditional pork grill, which uses the same cut of pork used to make bacon. Once the meat is cooked, you place a piece or two in a large lettuce leaf, add onions, garlic cloves, a dipping sauce or two, and any of the other side dishes on the table. You then wrap it tightly together, and place it whole in your mouth while trying not to make a royal mess of the table / your lap. Or at least that was my experience; other people didn't seem to have that trouble. The next course was a marinated strip of meat off of the rib, which was even more delicious due to the marinade. The grand finale was the beef, which went perfectly with a few onions, a clove of lightly cooked garlic, and vegetable oil/salt/pepper dip. Talk about perfection...

Actually, I might have had this day's dinner and the previous one switched. Either way, after a nap, a small group of us purchased some soju at ridiculous prices (1000/bottle), and drank in front of the hotel while discussing the possible geopolitical climate of the 21st century. Well, we at least talked about which languages would be best to learn...which depends on which country is dominant in 20 years (*cough*China*cough*). It was a good time, but the need to pack eventually caught up with us, and we retired for the night.

So I've learned a fair amount about Seoul, including:
  • They need better sanitation...the sewer waft in the side streets makes street food unappetizing (well, more unappetizing)
  • For those familiar with racing, you'll know that if you are not at full throttle/brake, you 're too slow. Let's just say that the city drivers have really taken this to heart.

2007/06/24

Orientation Day 3

The 30th anniversary of KOSEF's foundation was celebrated in a day of lecture and fine dining at the Westin Chosun Hotel. from 9:30 to about 12:00, there were 4 presentations from reps of various Asian equivalents to the NSF. The real meat-and-potatoes messages of their presentations seemed to be:
  1. Science funding agencies are good,
  2. KOSEF is a science funding agency
  3. Happy Birthday KOSEF
  4. Other countries also have science funding agencies, which are also good.
  5. New Zealand accents are funny
To present those facts took several hours of broken english and poorly formatted slides. Now, I must emphasize that the ability to speak more than 20 words of a foreign language is something I seriously respect, and so all the presenters deserve praise for their abilities and effort. The presenters did the best they could with a dry and boring topic. The result, unfortunately, made me want to make the razor-to-wrist gesture, if not actually carry out the deed.

Luckily, the lunch was packed with a variety of foods and styles, and we all left full and sated. The latter half of the presentations were far better, with the highlight being a scientist from Florida who basically said that our present climate of science taking a backseat to politics is akin to taking the titanic full speed ahead across the North Atlantic. He was blunt, somewhat inflammatory, a bit overzealous, but made his point more clearly and effectively than the rest of the presenters put together. He reminded me a lot of Richard Dawkins, due to both his accent and his position strongly in favor of rationality.

As we walked through the street market after his speech, we noticed that there were several street preachers with bullhorns broadcasting to the hip, young crowd. It was sad, really...these tired and weathered souls were likely haranguing the masses about whatever the latest deadly sin is. It was futile at best, and probably counterproductive, since any God that needs his word spread in that sad a manner is a weak deity. As schizophrenic as He was, at least in the old testament God knew how to make certain groups of people very aware of his presence. Now it seems that's not even possible.

The dinner that followed was probably the best food we had eaten on the trip to date (left, again courtesy of Margie). A traditional meal was spread out into something like 6 courses. Some of the better foods were raw fish, pickled greens, a sort of sesame-and-rice tortilla with 9 kinds of filling, grilled meats, squid, and a sort of scorn jello. While almost everything ranked somewhere from "interesting" to "delicious", the acorn jello was less appetizing than it looked. Imagine mud & hot pepper Jello jigglers...
The alcohol was consistently good, from the light but effective beer to the tart but fruit bek-se-ju (a kind of wine). One thing I've noticed is that consumption of Korean alcohol tends to be self-limiting. The first glass or shot of soju is cold and delicious, but by the fifth it's lukewarm and about as palatable as rubbing alcohol.

For the big night out, we split into 2 groups. Erica, Margie, Theresa, Matt, Nastaran, and I headed for the stream, while Jon, John, Amy, and Ben (?) went to Itaewon to drink and shop. The "stream" was a little waterway that was covered up by the Japanese during the colonial period. It's a big point of pride that it has now been uncovered, and the flow restored through downtown. Think of the sight and smell of Tookany creek (with sidewalks), for those at home. There were rocks in the middle to cross or take pictures on, and Several bridges that covered spots for people to stop or sit and enjoy the water. The highlight of the stream is the 600 ft. mural depicting a royal funeral procession. Every member of the procession is represented in detail.

We eventually left the stream and headed to Insadong market, which was coincidentally the same place I visited in October to purchase gifts and test my Korean phrasebook-reading skills with Keith. It was mostly closed when we arrived, though there was still the occasional street vendor with odd-smelling fried things on a stick, or shoes or tea or something. The tea shop we ended up visiting was a hole-in-the-wall place, but the tea was top notch. The 6 official flavors of tea we tried were:
  1. plum (hot)
  2. plum (cold)
  3. pine
  4. chrysanthemum (hot)
  5. cherry
  6. some kind of root
what they actually tasted like:
  1. plum
  2. hot plum
  3. sherry and pine nuts
  4. fresh clarinet reed
  5. cherry jolly rancher
  6. chinchilla fur / cage
Everyone was skeptical of my analysis, but I did get some agreement on the chinchilla one. We returned to the hotel afterwards without drinking any alcohol, a shocking rarity during orientation week.

Orientation - Day 2 (finally)

It's a wonderful way to start the day when the sun peeks through the curtains...about 2 hours after I first woke up. Feeling relatively refreshed (considering the brevity of my rest), I lazily threw on some of my better casual clothes (thank you, Laura). After several awkward exchanges with the hotel staff, I managed to find the buffet restaurant which served such traditional Korean dishes as French toast, bangers, bacon, rolls, brown eggs, and toast. Naturally, there was rice and a big bowl of kim-chi to complement it.

Fast forward 1 hour to our trip to the royal palace. After a bus tour of the grounds, including a peek at the president's "blue house", we stopped at the main gate and watched the changing of the guard. Bear in mind that the sand drilling grounds in front of the palace had essentially no shade, and the 10:00 sun was made it uncomfortably hot even in shorts. The actors were dressed in traditional Korean ceremonial dress (photo courtesy of Margie):
You'll notice that each guard is wearing at least 3 layers of heavy clothing, along with a black hat and large, thick boots. Despite the sweat-inducing conditions, they did an admirable job of illustrating the process. In a nutshell, the new guards march out from the barracks, line up face to face with the old, exchange documents and other affects, and then the old guards march out.




Throughout the whole process, there was traditional Korean flute music playing. The procession would play the instruments you see in the photo. The drums were powerful and resonant, especially the large bass (left). The horns sounded like someone had backed a truck over them first, but they played them with all the pomp they could muster.







The palace itself was impressive, with what must be tons of ceramic tiles supported by a dense, hand carved trellis of logs. The stone bases of the palace buildings were essentially open chimney, so that cooking fires in the kitchen also heated the floor of the entire building. As such, the palace and related buildings are single-story, so that the inhabitants can always be near the source of heat (the floor). Since ancient Koreans pretty much did everything there (eat, drink, sleep, 'sleep',etc.), they kept the floor as clean as we would a table (hence the taking off shoes and whatnot).

We noticed as we were leaving that the palace was a popular destination for school children. You could tell each school because all of the kids wore the same color uniform and backpack. Some of the more outgoing kids were anxious to apply their English lessons, waving enthusiastically at us and cheerfully shouting hello.

Lunch that day was Korean/Chinese fusion, which basically means the chef can play fast and loose with ingredients and proportions. Luckily, we Americans didn't really know the difference, so it worked out perfectly. They loaded fried and boiled meats, vegetables, rice, kim-chi, beer, and soda onto a big revolving tray on our (circular) table. This was the first of many meals in which I was determined to grow a set and ignore the persistent burn in my mouth (more on this later)

A short hop across town brought us to the '63' building, which is functionally equivalent to the Empire State building. It has an observatory that lets you see most of Seoul, as well as a days worth of LED production from Samsung to light and decorate the food court. Think of an entire corridor modeled after the warp core of the Enterprise-D, only with changing colors.

The introductory symposium we attended next was meant to be a classy and formal end to our first day. We dressed up, had a banquet-style dinner (of "western" food, to Sarah's vocal disappointment), and met some of the higher-ups in the NSF and KOSEF. We received a very generous gift of a 1GB stainless flash drive, as well as 400000 Won of our living allowance. We then found out we were supposed to make a brief speech about our research topic. Channeling my best Dr. Oh, I started from the basics, explained the what and why, harped on collaborations, and 3 minutes into my 1 minute spot, ran out of things to say.

The highlight of the evening had to be the 5 minute video introducing KOSEF and NSF's partnership. They meant well in producing it, I'm sure, but the result came off like five separate, 1 minute commercials stitched together in windows movie maker. I heard the phrase "strategic development" at least 3 times, and and no point in the video did they cite specific examples, present any facts or statistics, or in any way support their claims of fostering partnership. I understand that it was meant only to be an introduction, but they wasted minute after minute saying the same thing over and over again. The message was essentially "Korea / America have scientists. Scientists need money to research. We give them money. We want to give them more money." There...add 10 seconds of fancy graphics for a solid, simple message. No bullshit, no using 20 words to say what you could with 5, and no patronizing an intelligent audience.

The first big night out started at the "Budweiser" Bar across the street. This illustrates the phenomenon of "imported=good", but we opted to drink soju and try some tentacled seafood. We shared stories of youthful indiscretions involving one or more of: (too much) alcohol, driving, broken windows, significant others, the men's bathroom, and overbearing mothers.

From there, the true partiers proved their mettle by going to a no-rae-bong (karaoke). John/Jon immediately distinguished themselves as having the biggest lungs and biggest spirit. It didn't matter that we collectively were kind of tone-deaf...we, and particularly they, had the enthusiasm. I've never heard "Bohemian Rhapsody" sung quite so. When Madonna worked her way into the song queue (inevitable given the group average age of ~30), Margie and Theresa did great justice to "Papa Don't Preach". Actually, I think they did it better, since they didn't have that reediness that makes Madonna a little annoying. There was Guns and Roses, more 80's music, even a ballad. I tried my voice at Superfreak, which worked fairly well, except that I forgot the rhythm in some spots.

During this time, events were unfolding that would precipitate heated negotiation of broken English and frantic hand gestures. A total of 9 beers were consumed @ 5000 each; what they didn't tell us was that we had to buy food too, and so snuck in a fruit tray. At the conclusion of the night we discovered its price : 40,000 Won. After counting, recounting, accounting, and negotiations, the price was whittled to 20,000 Won. The value of the lesson learned was greater...in particular the phrases "an-ni-yo" (no) and "no-mu" (too much).

Big discoveries of the day
  • Due to wartime destruction, Seoul is on average a very new city, with most buildings dating to the 1950's or later
  • KOSEF did not spare any expense on the tours, meals, and accomodations
  • Government agencies can't do marketing
  • Always make sure of an establishment's ordering rules ahead of time
To see the rest of Margie's extensive trip photography, visit her Picasa albums here:
http://picasaweb.google.com/MSSBlueJay/200706KoreaPartI

2007/06/21

HUBOway

After a few days here, I found out that Dong-il Choi (ME Masters student) has been working on the so-called "HUBOway" for the past 1.5 years as a thesis. The project is meant to be a simplified, COTS version of the segway. After 6 months of development time, he built the first model; since then he has made 6 more, some of which are used at other universities.

As it turns out, Dong-il has accomplished what our team could only dream of: full balancing and command input with optimal control. It uses Pb-Acid batteries (24V), S28-150 motors, a TI F2808 DSP, and 2 OSMC's. It's about half the weight of our version, uses only 2 belts /motor for speed reduction, and requires a fraction of the machining time to build. Those rumors about these guys being the best of the best are so, so true. The contrast between HUBO and DASL has never been more shockingly obvious.

Besides having the best people in the country, there seems to be several main reasons why this lab is so advanced:
  1. Parts. The sheer volume of electronics, connectors, SMD components, nuts, bolts, springs, and everything else is staggering. There is almost an entire room, at least 12'x12', devoted to wall racks and bins full of components. As I've said before, if you want to build something rapidly, you can't wait around for several days every time you need some trivial piece.
  2. Standard Electronics. As part of the HUBO project, the lab has developed a simple, effective 48V motor driver based on the F2808 DSP. These motor drivers are used for almost all servomotor applications, including other robots, experimental legs, and small projects. Similarly, they have a standard 2808 DSP breakout board that is used for all of the small robots. This chip is powerful enough for almost any small robot, and the board is only 1.5"x2". It has a standard plug, and so any module can be plugged into any board, making it simple and easy to replace or upgrade. Compare this to the PICs that our lab uses, which have caused untold weeks of delay due to lack of computing power and lack of peripherals (see Vefa's project).
  3. Machine Tools: The CNC machines available to the lab are capable of producing robot parts quickly and accurately. Given the time usually spent on solid modeling, being able to tell a CNC machine to simply make a part as specified would save hours of drawing and manual machining. If multiple identical parts need to be made, all you need is more stock.
  4. Advising. Dr Jun Ho Oh seems to be around almost constantly, giving students technical advice and helping to solve problems. The PhD students also help advise the master's students. This way problems are solved quickly, before too much money and time is spent barking up the wrong tree.
The price of all this infrastructure cannot be overlooked, as likely $10,000,000+ have been spent on tools and equipment. Regardless, what this lab demonstrates is just how far you can go if students' time is not wasted solving problems that shouldn't exist in the first place (such as lack of computing power), or problems that have already been solved (such as how to machine a part accurately).

Orientation in review - Day 1

Day 1 - The Trip over (2007/06/11-12)

For some reason, long flights feel like an adventure. Maybe it was because I had a good reason to watch movies and goof off. After 9 months of senior design, and 2 weeks of preparations, it seemed like a break was in order. I certainly wasn't there for the food, though it at least kept me alive through the trip. As such, the best way to summarize the trip is through what I did to ignore it:
  • Started The Good Shepherd, which was impossible to hear over the airline headphones
  • Watched The Namesake, a surprisingly good movie about a Bengali couple that emigrates to the US in the 1970's. It focuses on how the kids grow up to be painfully American, and how it tears the family apart (conflict between traditional and modern values, etc.). Definitely worth seeing
  • Watched Ghost Rider, which deserved a spot on my facebook movie review page, it was so bad.
  • Saw 1 episode of House, where he (shockingly) cures some guy who (also shockingly) finds his bedside manner abrasive.
  • Realized in short order why the John Grisham novel I had was in the clearance bin.
The trip ended with a cheerful reunion of all the EAPSI participants at the terminal. Considering they didn't have a sign, the fact that we all met up was something of a miracle. When we all did though, it was great to catch up with everyone. While most of us were a bit apprehensive, it was obvious that Sarah was in her element. She had lived in Korea for several years, and is completely fluent in Korean (well, as far as I can tell). After talking with our guide, we were off to the hotel. The place is best described as an island of western culture in the middle of Seoul. As nice as the ambiance and furnishings were, I would have slept on the floor of a 40000 Won/night love motel if it had a computer (which they do, as I recall). Of course, after dinner was finished, we were all so beat that the marble floor of the lobby was looking soft and comfortable.

Next time...The first day out