Flexure Control for Long-Reach Manipulators

Original Flexure Control Test Bed at PNNL

One major problem that the Department of Energy (DOE) is faced with at the Hanford Nuclear Reservation is to clean out the radioactive waste tanks.

One issue relating to these tanks is the use of a large robot to clean the tanks out. Unfortunately, the access holes in the top of the tanks are small (4-42 inches, 12 inches in most tanks) and they have very large diameters (75 feet). This means that a robot must enter through a hole that is 12 inches in diameter and reach out 75 feet. A robot that is capable of doing this is inevitably going to vibrate every time it moves. However, by using the links at the end of the robot, (in our test bed, use the small robot at the end of a flexible link, which is attached to a big robot) you can damp out the vibrations using the small robot's inertial. This was successfully implemented in our lab on the robot pictured above and was able to damp out vibrations in 2 seconds that would take 40 seconds to naturally damp out.

Project Contact: J. Tucker