UPDATE: New arm segment pressure tests are currently
underway to reflect an increased operational pressure of
3psid. Results will be posted upon completion of the
The first arm to be tested (under the old operating
pressure of 2 psid) demonstrated excellent strength
during burst testing. The goal of such testing is to
reach three times operating pressure without failure.
The results of the first test are summarized below.
||Reach 3x operating
pressure without failure.
||3x MX-2 operating
pressure of 2 psid
||3x EMU operating
pressure of 4.3 psid
restraint line, no catastrophic failures.
With improved restraint line design, we are confident
new burst testing will demonstrate the same success.
Quality Assurance & Leak Testing
Each arm manucatured for operation must also pass a
strength test as a form of quality assurance. The goal
of such testing is to hold 1.66-2.0 operating pressure
while minimizing leakage rates. The results from the
first two arms tested (under the old operating pressure
of 2 psid) are summarized below.
identical arms to 1.66x - 2x operating pressure.
Maintain arm leakage < 1% suit flow.
sccm (1% = 1,700 sccm)
Joint Torque/Range of Motion
The goal of providing the capability to replicate the
joint angle limitations and torque requirements of an
actual pressure suit for some selected body joints is
perhaps the most difficult goal to accomplish for this
project. The design and fabrication of fabric mobility
joints has been the focus of much research in industries
and in space agencies around the world. It is not the
goal of this project to invest an equivalent amount of
time and money into this research, but rather to provide
a reasonable approximation to the limitations and
abilities of actual pressure suit joints.
To do this, a bench top experiment has been developed
to help characterize joint toque behavior. This same
setup examines range of motion as well. Joint segments
(currently only elbow segments) are built and
pressurized. A digital force gauge records force exerted
at the end of the segment while motion capture software
records the motion of the arm segment. This information
can then be reduced to joint torque and rotation angle.
While much more testing is needed, an example of some
preliminary data is illustrated above and to the left.
Our team is currently working to have a fully
pressurized system up in the near future. From
here, the following tests will begin in order to prepare
for our manned dives:
Unmanned air system
training and simulation