Servo - September 2010

Then

d n a

NOW

ROBOT MANIPULATORS by Tom Carroll

My wife and I recently returned from a vacation in Hawaii. One of the highlights was a trip on one of the 48-passenger Atlantis tourist submarines. Earlier, I happened to have met the senior pilot, Brian Ott of the Atlantis IX, based in Lahaina. He and his wife happened to be taking a short vacation at the same resort where we were staying. Sitting by one of the pools, we got to talking about his submarine. He knew that I had an interest in submarines and was ‘into robotics’. We were discussing the underwater remotely operated vehicles (ROVs) that were trying to stop the Deepwater Horizon Gulf oil spill disaster and how they used their robot manipulator arms in various underwater tasks. Brian thought it might be interesting to have a pair of robot arms and ‘hands’ to pick up and examine various items he saw on the ocean floor, though tourist subs are certainly not research vehicles. He felt that a pair of arms working together like his own would work best, not just a robot arm as one would find on an industrial robot. During my trip in the sub, he allowed me to sit in the pilot’s area with him and I could easily see how his view of the sea floor through the sub’s large four foot diameter domed port (at the bow) made objects enticing enough to pick up and examine.

Sub Systems

Brian and his crew spent a few minutes showing me some of the submarine’s different systems while there were no other tourists aboard. The Atlantis IX is part of the world’s largest private submarine fleet. Each of the multi-million dollar vessels are meticulously built. Figure 1 shows the Atlantis IX surfacing aft of the surface support vessel. I was amazed just how much of each subsystem was controlled in the same manner as mobile robots (especially high power combat robots). At 65 feet in length and displacing 80 tons, the sub runs on 20 huge 12 volt lead acid 1,280 amp hour batteries. The main bi-directional, brushless thrusters (two 20 HP main stern, two 10 HP vertical, and one 10 HP bow) and 20 1,000 watt exterior floodlights