Answer to sTEm–at-Work Puzzle #32: Performance Test for Surgical Robot Arm

Puzzle 32 (Published in Jan 2013 edition of the FLATE Focus)

At first glance at this puzzle the student might declare that the puzzle is not fair because it has a complicated trigonometry based equation associated with the plotted data. It is certainly true that an engineering technician has to be comfortable with algebra and trigonometry concepts. Thus, the puzzle can be used as a segway into review of the sine function and the idea of a repetitive signal. However, this puzzle just required command of the fundamental graphic reading skills that these puzzles keep emphasizing as well as the sine function value at zero.

In this case, the plot indicated that the initial rest position voltage value should be 2 volts. However, if zero seconds is inserted into the equation that describes the plot, it is very clear that the equation says that one volt is the required signal to bring the arm to its rest position so that the operational test can be initiated. The role of a change order can also be expanded upon. In this case, the technician knew the graphic was not correct and understood that the process was not to just change the graph, but to initiate a change order which will send the document back through the system to make sure that the correct change is made in this and connected documents.

Solution Answer: YES. There is a flaw in this expected performance graphic and the change order is required.