|
|
|
|
|
|
|
|
|
|
Ask students if they have ever seen a robot. (Even if no one has
seen a robot at close range, students will certainly have seen robots in
books, in movies, and on TV. Allow them to describe what they have seen.)
Ask: Do all robots look like mechanical human beings? Why do people make robots? Might there be a design that would be better for some projects than the shape of a human being? For example, can human beings move quickly through water and stay under for long periods of time? Explain that remotely operated vehicles (ROVs) like JASON and Medea are robots but do not look human because their function calls for another kind of design.
|
< < go top
|
|
|
Robots can do some things humans cannot
do. Human beings can work with robots to accomplish tasks that would not
otherwise be possible. Today's robotic technology even makes it possible
for humans to conduct activities without being physically present. The
JASON Project uses robots to explore the deep water environment.
|
< < go top
|
|
|
Students will be able to do the following:
- Define robot and ROV.
- Identify suitable work for robots and ROVs.
- Describe work JASON is expected to do.
|
< < go top
|
|
|
- Transparency made from Master 1.1j, JASON Transmission System
- Transparencies made from Master 1.1g, JASON and Medea
- Transparency of Master 2.1a, Kinds of Robots
- Overhead projector
|
|
< < go top
|
|
Activity
- Project Master 1.1j, JASON Transmission System, and point out JASON.
Project Master 1.1g, JASON and Medea. Explain that JASON and Medea together
form a two-vehicle team able to do both wide-area and detailed surveys of
the sea floor, as well as detailed sampling. Medea stays higher than JASON
(about 15 to 25 meters-or 50 to 80 feet-off the bottom), and JASON works on the sea floor. Neither carries a passenger. Medea has no propulsion, but JASON is
equipped with thrusters that allow very accurate movement. JASON can be
"flown" manually by a pilot in the command center or can be operated in closed-loop control. In closed-loop mode, JASON is given a set of commands
to follow (such as to fly a 100-meter [328-foot] grid pattern at 10 meters [33 feet] off the bottom) and through a sophisticated computer control system is able to do so.
Ask: Why use JASON instead of, for example, a submersible and crew? Time at
sea is very costly--tens of thousands of dollars per day. A typical day on
a submarine expedition begins at about 4 a.m. with the engineering teams preparing the submarine. At 8 a.m. the three-person dive team enters the submersible, the hatch is closed, and the sub is lowered into the water. By about 9 a.m., the sub begins its descent. Usually it takes about three hours and can cover about five kilometers (about three miles). Visibility from the sub is very poor (less than five meters or 16 feet), and only three people (two scientists and one pilot) share the experience. After three hours, the submersible begins the two and-a-half-hour trip back to the surface. By about 7 p.m. the submersible is back on board, and the day's submarine activities are over. The net result is ten hours for every three hours of direct observation of the sea floor.
In the case of Medea/JASON, the system is deployed and left in the water
for days. A team of up to ten people can comfortably experience real-time
observation in the control center. A wider area can be imaged, since Medea
has a bird's-eye view that includes JASON and JASON's viewing area. The
real-time satellite transmission enlarges the direct observation audience
to the total capacity of the downlink viewing sites. These ROVs and their
human operators are good examples of humans using technology to overcome
human limitations.
- Project Master 2.1B. Kinds of Robots, and explain that it's hard to
define all robots by what they do, because they perform such a wide range
of tasks. Remind students of their earlier ideas about why people might
want to build robots. Students may think of robots as playthings or
mechanical butlers, but working robots are usually designed to perform
tasks too tedious, too precise, or too dangerous for human beings. In
space, at the bottom of the ocean, or in a paint booth engulfed in toxic
fumes, robotic machines can keep going without oxygen and at temperatures
too high or too low for humans. Robots can be sent into dangerous places
and controlled from a safe distance by a human operator. Robots can fight
fires and can be used for bomb disposal work or for sweeping mine fields.
Some robots are programmed to vary their motions autonomously, by means of
special "teach units" that move each joint of the robot in the desired
direction. Some robots (called "bang-bang" robots) have their mechanical movement stopped at either end of their range by fixed blocks. They bang the fixed block at one end of their path and then bang the fixed block at
the other end. The data center tape cartridge robot "sees" the correct cartridge by means of a camera and two lights mounted on each "hand." The robot takes the cartridge from its slot on the rack, moves it to the tape reader, and mounts it--all in 11 seconds.
JASON uses similar technology and takes its commands from human operators
who can see by way of TV cameras as if they were inside JASON
looking out. The joystick commands are sent from a shipboard computer
through a fiber-optic cable to the computer on JASON, which responds by
turning on JASON's thrusters. Sensor information (water depth, heading, and
position, among other things) is sent from JASON's computer back to the
computers aboard the ship, which display the information to the operators
and store it for later use. The information links between the computers
make up a local area network, which is similar to the local area networks
many business and universities use to pass information between computers.
The local area network must pass information very quickly, or the pilot
will be hampered by the delay between the joystick commands and JASON's response. The network used on JASON will eventually be able to send information at the rate of 10 million bits per second. This is comparable to sending the
contents of a 750-page book every second. In reality much less data are
actually sent, but the speed capability is very important to controlling
JASON well. The shipboard computers are split into separate tasks;
individual computers control JASON, acoustically determine Medea's and
JASON's positions, and store and display the data coming from the sea
floor. JASON's computers accept commands from scientists aboard the ship.
|
< < go top
|
|
|
|
|
|
|
Pose the question: Why are ROVs so important to
exploration? Remind students that JASON will be operating at a depth of
about 1,135 meters (3,722 feet). JASON can work at 6,000
meters, or almost 4 miles down. Remote operation is ideal for work
beneath the sea, where darkness, high pressure, and low temperatures permit
only brief, dangerous trips by humans. Robots designed to be used
underwater are called submersible ROVs.
|
< < go top
|
|
|
|
Last modified: 11-June-99
Copyright Notice
|
|
Deep Sea Technology - Robots and Submersibles