Week 6: Discovery!

Note: In the craziness of the last week (The program was 7 weeks in total), we didn't get around to posting this until just now.

This past week marked a bright zenith of our time spent exploring the Chavín monument. Each week we have had the privilege of expanding knowledge of the duct and canal systems in the site, but last Thursday we had a particularly special treat. After many hours of driving our robot down ducts and finding them full of little more than stones and spider webs, we found an unbroken ceramic vessel from the Chavín period with our robot!

The morning started like many others this summer - walking to the site after breakfast to explore ducts using our robot. Daniel and I, along with our friend, visiting Mechanical Engineering PhD student Margaret Coad, entered an underground canal below a main excavation area in the site. The day before, a French archaeologist named Melanie Ferras had taken us into the same canal to show us several small ducts that she hoped we could explore with our robots. Melanie had spent the past few seasons excavating this canal, but she was unable to explore all of the ducts connecting to it. Some were too small for excavation, while others were simply challenging and low priority compared to the main canal. We returned with the goal of exploring two ducts nearby each other, one with the wheeled robot and one with the vine robot. The canal was like many others - cramped, dusty, full of dead mice and lizards, and plastered with spiderwebs. After helping Margaret transport all of the vine robot components into the canal (an air compressor, power convertor, 10m extension cable, pressure regulators, and the main body of the vine robot - no easy task) Daniel and I started up our wheeled robot and put it into a duct connecting to the ceiling of the canal. From the entrance to the duct, all we could see we was the quotidian rubble we had come to expect from underground tunnels: scattered rocks and dried mud flanked by mortared stone walls, overhung by large stone beams. We started to drive the robot down the tunnel, and after only a few yards we noticed a large, globular object resting on the left side of the canal.

Driving closer, we clearly saw that the object, whatever it was, had been made by humans. It looked like a dirty vase or a bottle or some other container resting half-buried in the dried mud. Not trusting our limited experience, we had no way of knowing whether the object was ancient ceramic or modern trash. This summer we have found all kinds of refuse inside of ducts: candy wrappers, plastic bags, crushed water bottles, discarded film containers, plastic spoons, unsmoked cigarettes. It is unclear whether these objects were inserted into the ducts by irreverent and determined tourists, or whether they were left there by earlier archaeologists. We do know that one of the first archaeologists in Chavín used small children to excavate some of the ducts down which our robot has been exploring. Since then, small adults have continued to enter some of the larger ducts in the name of archaeological exploration.

After collecting thorough video documentation of the object with our robot we continued to explore the duct and then returned to the lab. Later, that evening, we shared the video with our PI, John Rick, who, upon seeing the shape of the object, instantly said, “that’s Chavín ceramic.” Everyone in the lab was thrilled by the discovery, and the question of how we could further study the vessel quickly arose. As with many archaeological artifacts, the route to a deeper understanding of an object often requires carefully excavating and cleaning the object. Then, in the lab, it is possible to critically examine the details of its shape, condition, and decoration (or lack thereof) with its position within the site in order to better understand the significance of the vessel within Chavín culture. The vessel was situated about 4 yards away from the entrance to the canal inside of a 16inch by 16 inch duct. Retrieving the vessel would require crawling through a very confined space and exercising utmost care while extracting it from the mud. Though the vessel looked unbroken, it could well have large cracks on its underside. Though we’d spent many days working in small spaces, I was hesitant about the prospect of crawling down that tiny tunnel. Daniel, however, enthusiastically volunteered for the job. The next morning, after talking extensively with John Rick about proper technique for extracting and documenting the position of the vessel, we returned to the canal. After taking some careful distance and compass measurements of the vessel, Daniel climbed through the ceiling of the canal, wedged himself into the duct, and started inching forward while pushing a cardboard box containing a trowel, a brush, and a cloth bag. The whole process went more smoothly than either of us could have expected, and the look on Daniel’s face when he finally pulls the vessel free from the mud is priceless.

The ceramic object turned out to be an unbroken, undecorated, and stunningly beautiful ceramic bottle: a classic example of polished black Chavín pottery. It was probably placed in the canal as a ceremonial sacrifice, which may explain the lack of decoration on the bottle. John Rick and others have posited that some sacrificial ceramics in Chavín were less likely to contain elaborate decoration. It was perhaps more important for a precious vessel to appear whole and unblemished before being smashed or entombed within the earth than it was to sacrifice a piece of truly elaborate pottery. One curiosity about this particular vessel is the position in which it was found – resting with the neck partially inclined against the wall. In the lab, debate continues over whether the bottle was carefully placed in that position or somehow washed or pushed by water or sediment down the canal and into that position.

When we brought the bottle out of the canal, work on the site stopped and everyone crowded around to get a better look. Unbroken ceramics of this size and form, from this time period, are extremely rare in Chavín, and artifacts like this only turn up every few years. Many folks commented on the proud parent look on my face as I cradled the bottle in the crook of my arm. Now, the cleaned bottle rests in the lab, most likely awaiting future examination in academic literature and a resting place in the Chavín national museum.

Besides the good luck of the wheeled robot, the rest of Margaret’s visit with the vine robot also proved a success. In some ducts the vine robot proved easily capable of passing over and through rock blockages that stopped our wheeled robot cold. We also grew the vine robot up vertical and near-vertical shafts in a different part of the canal system. The improved fabric body and new camera attachment that Margaret constructed before coming to Peru worked well, and the vine robot allowed us to expand knowledge of several key ducts in the site. We were all happy with how it performed. Daniel and I are excited to see how it continues to develop, and we are curious what improvements Margaret will design next! We will be visiting the Okamura lab once school starts up again to say hello and revisit some of the memories we made together in Chavín.

During the past week our work hours were dominated by time spent underground, but our time off was full of eating adventures. Despite the warnings of our elders and some of our peers, Daniel, a few friends, and I couldn’t resist going out to eat at a Chifa restaurant in downtown Chavín. Chifa is the Peruvian take on Chinese food, and it is generally fast, cheap, salty, and delicious. Two days after the meal, our stomachs as happy as they’d been all summer, we returned to Emily’s open air Chifa restaurant for a second helping of Aeropuerto and Combinación, dishes that combine fried rice, noodles, meat, and vegetables. After that success, Daniel and I decided to eat pollo broaster con papas (breaded and fried chicken with fries) from a street vendor. While waiting, we ran into the Chavín site tourism director, Anna, and started talking to her about Peru and archaeology more broadly. In the end, we waited on the street for more than an hour, but the warm, crispy chicken and the enlightening conversation was worth it. Before saying goodnight, Anna invited us to come to a pachamanca, or earth oven, feast that the site workers were putting on the next day. The following afternoon, Daniel and I walked down to the river, expecting a small sample of the food on Anna’s plate. Instead, the site workers generously gave us large plates of deliciously seasoned pollo (chicken), chancho (pork), papas (potatoes), camotes (sweet potatoes), choclo (Inca corn), platanos (bananas) and haba en vainas (beans). Anna and the workers encouraged us to eat all the food and compelled us to wash it all down with several large beers (all of which ended up in Jack’s stomach, because Daniel does not like beer). We left with taut bellies and wide smiles. So far, despite all of our adventurous eating, we have (mostly) managed to avoid any serious gastrointestinal distress. Huzzah for new culinary horizons! (A brief edit: as of this posting, Daniel is experiencing some discomfort (to put it extremely mildly) thanks to some pollo a la braza that we ate last night in downtown Chavín. But this has only somewhat dampened our triumphant tone.)

We are now in the midst of our last week in Chavín. So far it has been a time full of project documentation, writing up a report for the Ministry of culture, finishing explorations of some ducts, and saying goodbye to the places and people we have come to love here in Chavín. We hope to write at least one more blog post recapping our project and describing our final days in Chavín, entonces, hasta la proxima vez.

Week 5: Vine Robots, Ducts, and The Great Outdoors!

By Daniel Chan

So much has happened in the last week! Last Monday (July 30th), Margaret arrived with the vine robot. It's a really interesting robot which is totally unique in its way of moving by growing, and Margaret and her colleagues developed a really cool way of attaching a camera to the front of it as it grows. If you're interested in learning more about the vine robot in general, Stanford made a really cool video showing it off here! (Stanford researchers develop vine-like, growing robot) Margaret spent a good portion of the week getting it ready with its new and more durable fabric skin, and we did a few tests at the end of the week! She spent Monday making some changes based on what we found, and we're hopeful that today we will be able to explore in areas past where our robot has been in the past. Everyone at the site is fascinated by the vine robot, and we did a joint talk this past Tuesday night to all of the Peruvian archeologists on our respective robots as well as the more general applications of robotics in archeology. We did it nearly entirely in Spanish, which was really great for our Spanish knowledge! Around 40 people showed up, from the Stanford archeology team, the Peruvian archeologists, and even the directors of the site, museum, and research institute were there.

Some unfortunate news we received this week is that the Global Engineering Program which we are funded through was recently canceled for future years, so unless something changes or funding can be found elsewhere, we may be the last group of engineers to come to Chavin. We've had an amazing experience in the program, and are working with John to create something to help show that the program is really effective, both for learning and archeological discovery. We hope he can find funding for future years!

One of our main focuses this week has simply been to explore anywhere and everywhere we can. We've been sending our robot down every duct we can find, taking video of the surroundings to see what we can find. Our hope was to find an undiscovered gallery in or under one of the buildings, but so far, we haven't found anything along those lines. One highlight was that our robot was able to make it down a 100 foot duct and we found out that two known galleries were connected by this duct! This wasn't on the map, and John didn't seem to know it previously, so it felt like a big win. Many other ducts are collapsed within 30 feet, and we haven't seen anything particularly new or exciting, but we hope that this knowledge of what is in the ducts will be helpful to future archeologists, even if we don't have a groundbreaking discovery.

We're also working on documentation and finishing up our work on the robot so that people in the future can understand and (hopefully) continue development on it. For those interested, we hope to publish our findings and make the whole project transparent and open source, both for future use in Chavin as well as potentially in other archeological sites.

In non-robot news, we've had a lot of time outdoors! Two weeks ago, Daniel went to Huaraz to eat a lot of food, and did a day hike to the beautiful Laguna 69, where it was snowing!

Last week, Margaret and I went on a spontaneous trip to camp on Shayapa, the one of the hills that forms the valley we are in. We had a really fun photo shoot of Margaret with the city lights below! This past weekend Jack and I were able to go with Margaret, Liz, and Alessandra on a backpacking expedition to Carhuascancha, where we hiked a total of ~18 miles over two days through a beautiful valley, and camped overnight. Because we don't have a camp stove we were limited to precooked food, so we boiled 30 sweet potatoes and 17 eggs, which lasted us all 4 meals with some sweet potatoes to spare. When we got back to our packs after an excursion Sunday morning, we found a cute puppy sleeping near our bags. After we fed it a sweet potato, it followed us on our hike for 4+ miles, until we came across its owners, a herding family. They told us his name, ironically, is Gringo because of its light fur. Last mini story is that Liz and I got haircuts! We paid less than 3 dollars each, and I got a more extreme haircut than I asked for, but I look a little like a Peruvian soccer player now!

This week, we're planning to continue documentation, exploring the rest of the ducts we can, supporting Margaret's vine robot, and making a few final improvements to the code. Thanks again to everyone who has been following along and supporting us!

Week 4: Robot rebuild, canals, and toros de muerte

After a morning spent underground. (Thank you William Penniman for the photo!)

By Jack Lane

Navidad arrived early this past week in Chavin when one of John Rick’s graduate students, John Wolf, arrived with a suitcase full of new parts for our robot. John Wolf, better known as “Lobo,” brought with him the following: new 3D printed wheel-hub attachments from our friends at the PRL (thank you Dan, Elliot, and Thom!), replacement wheels for those we had lost, a new set of motors, two fish-eye cameras, and a fresh spool of wire, as well as various switches and connectors. He also bought a lifetime full of unpredictable, engrossing stories and excellent taste in music. This past week in the lab, Lobo has entertained us with tales of learning how to weld in order to help his friend build a 52-foot, concrete boat and getting kicked out of college in the 60s because he occupied the student union in an anti-war protest. He also introduced us to the soulful, rock/blues crooning of Beth Hart and Dana Fuchs, which has provided a welcome soundtrack to the (at times tedious) task of rebuilding our robot. We still haven´t completely adjusted to the daily novelty of seeing Lobo working on human skulls in the lab.

After losing our first set of wheels and MacGyvering a solution out of extra wheels and epoxy, we embarked on a full overhaul of the robot. As described in our last post, this overhaul includes many small changes and improvements. The largest change has been a rearrangement of the main internal components of our robot in order to narrow the wheelbase and reduce the overall height. We have also, however, used this opportunity to redesign our software, build a graphical user interface, transfer controls from a computer keyboard to a joystick, add a backup camera, and mount a distance sensor on the front of the robot. One of the most challenging constraints on our work in Peru has been our limited access to tools, parts, and prototyping materials. We’ve had to make changes to the chassis of our robot using a hacksaw and a hand drill, often holding the parts by hand because we lack any proper means of fixturing. Aside from the bounty we received from Lobo, we are generally limited to using the parts and tools that we brought with us. Our hot glue gun has arguably been our most indispensable tool, and we have become more and more reliant on its gooey goodness in order to support wiring, adhere lights, and mount cameras. Increasingly, we are cannibalizing parts for use beyond their original, planned purposes. We have taken the majority of the 1/8 acrylic parts that we laser cut before leaving the states, sheared them into pieces, and added them (with hot glue, of course) as extra support for wiring and camera mounts. Overall, the process of shrinking and refining our robot has required improvisation and arts-and-crafts know-how, making for an entertaining week in the lab.

After making many of the above changes, we returned to the site for more exploration, this time in the underground canal system. As we briefly described in a previous post, there are broadly three types of underground spaces in the Chavin monument: galleries, ducts, and canals. The galleries are ceremonial spaces enclosed inside the temple buildings – within they are tall enough to stand upright and at times wide enough to walk two abreast. Ducts are small tunnels that connect galleries and are thought to have provided ventilation and illumination to the galleries– the largest ducts are just big enough for me to squeeze inside while the smaller ducts are around 8 inches wide and tall. Canals, on the other hand, are completely below-ground, and their primary purpose seems to be for draining and moving water through the site. Like ducts, canals vary in size, but they are generally larger, sometimes big enough to allow a small person to walk through them in a crouch. Until recently, all of our explorations with the robot have all taken place inside ducts, but that changed this past week. With the arrival of two Peruvian hydrological engineers and encouragement from John Rick, we began exploring canal systems in the site. We hope to generally extend knowledge of the canal system by further mapping underground canal spaces. The holy grail of our canal search would be uncovering an intake from the Wacheqsa river or outtake to the Mosna river. In particular, an intake to the canal system from the Wacheqsa river would provide strong evidence that the Chavin could control water flow into the canal system and even pressurize the system in order to send water uphill towards some of the temple buildings. If true, it would make Chavin the only known site in the New World with a pressurized water system.

So far, our exploration of the canals has been a process of rediscovery more than a successful uncovering of new spaces. Current knowledge of the canal system among the archaeologists here is extensive but fragmented. Oftentimes they are unsure exactly what lies at the end of various canals – it could be a complete blockage, or it could be a small opening just large enough for a wheeled robot. Oftentimes we need to crawl into the canals ourselves in order to find spaces for our robot to explore. Last week, after crawling for about 45 minutes through tight underground spaces, we found that one of the main canals ended in a narrow tunnel extending to the north. It was just a smidge too small for the last version of our robot, and we hope to return with our smaller, improved robot. Our search was limited by the size of robot in other locations as well, and by the end of the week we were left, once again, unfulfilled in our quest to discover new spaces in the site.

In the process of exploring the canals, we ran into yet another unexpected problem with our wheels and motors. The large MacGyvered wheels that we made were slipping, bouncing, and generally losing traction in the canals. Upon closer inspection in the lab, we realized that the gear boxes of our motors were severely worn. The gears didn’t seem to be slipping, yet, but they were suffering from pronounced backlash, and the cantilevered motor shafts now wiggle 5 to 10 degrees off their axes. We suspect that this wear was particularly pronounced because the large motors stuck out markedly from the body of our robot and placed a large, perpendicular moment on our motor shafts. The final step of our robot redesign over the past week therefore became, once again, the process of replacing our motors and wheels. We have now returned to our original wheel and 3D printed hub attachment design. The hub attachments, however, are now printed out of a rigid resin, and the connections are reinforced with epoxy. We hope that these changes are enough to prevent the wheel-loss tragedy that we faced two weeks ago. Every day our robot becomes more compact, more refined, and closer to what feels like a final, finished product. We have three more weeks left in our program, and we hope to spend the majority of that time exploring in the site rather than tinkering in the lab.

In non-robot news, the past week was a busy time in Chavin. The town fiesta started last Friday with a street party featuring two bands and a castillo (firework tower). That night of music was followed by about 48 hours of nonstop fireworks, marching bands, and dancing throughout Chavin, especially in the main plaza. The fiesta concluded with a bull fight on Wednesday in the plaza de los toros de Chavin. Most of the Stanford students, Daniel and I included, were trepidatious about the fight, but ultimately decided that the experience was too novel to pass up. The show started with beautiful dances featuring Caballos de paso Peruano, a type of Peruvian show-horse, and then progressed to the first of three toros de muerte. The bull fighter was from out of town, and went by the moniker, “el poeta.” His garb was a bedazzled piece of anachronistic colonialsm, the traje de luces – royal blue with gold bangles and knee high pink socks - and a montera hat. The fighting and the killing of the bull itself was surprisingly tidy, but gruesome all the same. The matador would bait the bull with his red cape before attempting to slide a meter-long sword directly between the bull’s shoulder blades as the bull charged past. The first bull took four swords, the last buried to the hilt, before falling to its knees. My curiosity more than satisfied, I left after the first bull died.

It is hard to believe that we only have three weeks left here! They will be a busy time. I (Jack) have joined a band with two of the Peruvian archaeologists, and we intend to perform on the first day of August. Currently, we go by the name Cabrones del Swing and play an eclectic mix of English and Spanish rock. The Peruvian Fiestas Patrias are this coming weekend, and Daniel plans to put on his archaeologist knee-pads and help John Rick with some below-ground excavations in one of the canals. We are also excited about the arrival of Margaret Coad, a graduate student from Stanford who is bring another robot with which we will explore the site. But we’ll write more about that in the next post.