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Robotic Choreography

Posted on July 19th, 2010 by Alex Forrest

DORA and UBC-Gavia in the water ready to deploy in Pavilion Lake.

Its now been just over a week since the end of our adventures at Pavilion Lake and, as I start trying to look at all the data we’ve collected, I can’t help but be impressed with our successes. In addition to the image mosaicing that I was working on, and showed pictures of in an earlier post, my specific focus of being up at the lake was running coordinated missions between the two autonomous underwater vehicles (AUVs), that we had on-site from the University of British Columbia and the University of Delaware, and the Deepworker vehicles. Our mission planning goals were twofold; joint objectives and joint missions.

Joint objective style missions measure parameters that are relatively static in time (i.e. photos of microbialites). This means that coordinating different platforms isn’t necessary but coordinating their datasets are. This requires that the timestamps of each data stream be precisely set and that the dataset is georeferenced to a high degree of accuracy. This work was started last year but continued this year by using the collected images from Deepworker and comparing it with AUV collected data (e.g. high-precision bathymetry).

Comparing multibeam bathymetry collected with DORA with detailed imagery from UBC-Gavia.

Joint missions involved a significantly greater degree of coordination as it involved running the vehicles at the same time as the Deepworkers. Our experiment this year was to look at the area of increased salinity at the bottom of the lake. To this end had the Deepworkers crossing the bottom of the basin at about 1 m from the bottom (> 55 m depth), while running UBC-Gavia at 40 m depth. The greatest debate was trying to decide what the minimum safe distance was to be between the two platforms! In the end we ran AUV missions down to 48 m without any problems. Although we’re just starting to process all of this data now, from both styles of missions, we’re excited about what new perspectives these combined datasets might hold.

-Alex

Mosaicing Microbialite Roads

Posted on June 29th, 2010 by Alex Forrest

As I near the end of my doctoral studies, I reflect on how different my thesis is from what I actually started four years ago but at the same time how much things come full circle. My involvement began when I started using UBC-Gavia, an Autonomous Underwater Vehicle, to map the bottom of the lake. Unfortunately, as a result of the slope steepness in this lake, we found it very hard to accomplish and so the focus of my thesis is on water temperature and physical transport. That said, I’ve maintained a soft spot for image mosaicing.

Gavia, the Autonomous Underwater Vehicle (AUV)

Just recently, we have been working with people from the Center for Coastal and Ocean Mapping (CCOM) and the University of Delaware to mosaic not only the images we have been collecting but also those Deepworker images. The first, and easier dataset to work with, was the flat sections in the middle of the lake which has been of interest due to the microbialite mats that have been observed there. These are easier to process as don’t have roll and pitch errors that are introduced. Below is just a very small sample of what the final product that can be generated.

Microbialite Mosaic

Mosaic of images collected by UBC-Gavia of microbial mats from the central basin (length of image is about 10 m long).

In addition to running AUVs, I am also lucky enough to participate in PLRP by being a Deepworker pilot and I was able to have my first flight yesterday. After finishing my mission yesterday and completing all my objectives, I was told that I had a bit of extra time left over so I leaped at the opportunity at testing my new found mosaicing skills. As I was coming back to the barge, I passed by what people around here call ‘microbiliate roads’; long straight lines of microbialite that are aligned along the slope. Lining up the camera, I tried to film a long straight line up the slope. Although the mosaic still has some error resulting from vehicle pitch – you can see this in the image by the fact that it begins to ‘pinch’ out – but I was still pretty happy with the first attempt.

So now the next step is to refine the processing so that we can start using these images for our mission planning for both AUV and Deepworker flights. Part of doing this is to clean the images to remove the roll and pitch effects and then we can drape these images over the bathymetry data that we are collecting. This will allow us to start creating a georeferenced map of the photos.

- Alex

Rebreathers and Robots

Posted on June 18th, 2009 by Alex Forrest

Robert A. Heinlein once wrote a book called ‘Have Space Suit – Will Travel’ but I would argue that the same thing could be said for underwater robots. During the past several weeks of preparation for this summer’s Deepworker deployment I have been doing some extensive travel with some of the other AUV (Autonomous Underwater Vehicle) projects in which I am involved. Two of the more interesting places have been Aberdeen, Scotland and Chesapeake Bay, Maryland.

The helicopter underwater escape training simulator

The helicopter underwater escape training simulator

The first of these was to do the Basic Offshore Safety Induction and Training course (BOSIET). This is the training necessary to prepare for potential rescue scenarios for transport to offshore oil rigs, and is required for an upcoming AUV project. One of the more intimidating parts of the training was an inverted exit of a flooded helicopter simulator. The simulator shown on the right is lowered into the water while you breathe through a rebreather (where air is temporarily stored in your life jacket). This allows you to breathe underwater for about 30 seconds and allows you enough time to release from the harness and push out the window and exit. This was a definitely a unique experience that puts a new perspective on working in and around the water, at Pavilion Lake and elsewhere over open water in the Caspian Sea and over sea-ice in the Canadian High Arctic.

Adam Skarke from the University of Delaware getting ready to deploy the Gavia vehicle

Adam Skarke from the University of Delaware getting ready to deploy the Gavia vehicle

On my return from Aberdeen, I stopped over in Chesapeake Bay to attend an event informally known as AUVFest 2009 where four AUV groups from around the United States met to perform a demonstration of their technologies, and to work with educators on how to transfer knowledge from the practice to the classroom. This was a fantastic workshop that really emphasized how every vehicle, with their varied sensor setups, fills a different niche for underwater exploration. For me, this really hit home as an important concept at Pavilion Lake, where we have a wide array of tools and vehicles that must be optimized in order to get the best scientific returns. Sharing the varied and extensive experience at this workshop showed that Heinlein was right with a slight variation: “Have AUV – Will Travel”.

~Alex Forrest

Exploring the Depths – 10 Inches at a Time

Posted on May 19th, 2009 by Alex Forrest

After several years of playing with underwater robots, last week was a new dimension with learning to “fly” the Deepworker vehicles as part of the training for the upcoming Pavilion Lake field season. The training missions were conducted in Vancouver’s Burrard Inlet over a five day period with myself and three other new pilots from the PLRP. The unique opportunity to operate these individual manned submersibles allows an unrivaled perspective in these underwater environments. The only unfortunate thing was that the perspective was somewhat myopic as the spring freshet (freshwater runoff during spring snowmelt) resulted in the water being quite turbid. On a good day, I was only able to see to the end of my camera. However, as you can see in the photo below, it is possible to just make out the reddish sea anemone positioned about 10 inches off the bow of the vehicle.

Anenome

Anemone at the bottom of Burrard Inlet

This type of exploration is also part of my ongoing personal research using humans and robots. For the past several years, as part of my doctorate, I have been involved with the deployment of UBC-Gavia, an untethered, autonomous underwater vehicle, in Pavilion Lake and many other places around the world. Last year, we were able to have both the Deepworker and UBC-Gavia in the water during the same time as you can see in the picture below. This year we’re planning to use Gavia and Deepworker in tandem to to explore incoming groundwater in the south basin of Pavilion Lake, which is an exciting opportunity for joint human/robotic exploration.

dw_gavia

Deepworker and UBC-Gavia together in Pavilion Lake

Pavilion Lake is a unique and exciting opportunity to use multiple vehicles for joint human/robotic science and exploration. Methods developed and lessons learnt from choreographing the increasingly specialized robots associated with this project (in terms of data collection, data management, logistics, etc.) would serve as a complementary model as humans reach towards manned flight to Mars and exploration of extra-terrestrial liquid bodies as potentially found on Europa (one of Jupiter’s moons) or Enceladus (one of Saturn’s moons).

-Alex