The NHC right side manipulator was evaluated today to check if operation was normal through all ranges of motion. The manipulator was first moved through usual motions without the electric motion drives: the feel was fairly normal, a sound could be heard from the master side Z motion tapes rubbing on the sides of the pulleys, this problem had been identified a few weeks ago however it was significantly reduced since the master side upper and lower Z motion tapes were tensioned yesterday (using CRL repair manual)
The Y motion drive was then tested: with the master arm close to the window we attempted to move the slave arm close to the slave side window using the Y motion drive; part way through travel the arm stopped moving and would not move any further towards the window. At this point it was approximately 1 foot from the slave side window. (I recall that when the manipulator was installed in the wall it was difficult to get the slave end fully horizontal, the arm would travel part way, then stop for seemingly no reason. Eventually after multiple attempts I got it to reach the horizontal position)
The Z motion was then tested. The slave end was moved to the fully extended position. At this point when the Z drive was continued downwards the master side moved up. Once it reached the upper limit the drive continued which caused the Z motion tape on the slave end to snap. At this point testing was stopped.
Our plan is to assemble and test the left side manipulator after the manipulator handling cart repair is completed. If the left side has the same problems it is likely a manufacturer defect. If not, the problems with the right side may be due to a timing error introduced when we removed the slave end to fit the assembly and cart through the roof hatch from the ISAC-1 experimental hall. In either case we plan to have CRL technician come in to address the issues and tune-up both arms before use. |