Space Grant Consortium - University of Wisconsin - Green Bay

LVDT (the w ire and r obot w ere m oving i n o pposite di rections). T his a llowed a w ay t o
investigate the s ynchronization of the two simultaneous movements. The LVDT cap tured t he
difference in position of the wire and the robot.
Figure 5 s hows the ve locity di fference be tween t he w ire and t he robot a nd that th e tw o
movements are not synchronized.
Figure 5 - Differential Velocity between X Axis and Wire Feed, 50 IPM
Figure 5 s hows m ovement be ginning at 0.75 s econds, w ith t he r obot s tarting b efore t he w ire
(pulling away from the LVDT produces a positive velocity). From 1.25 to 2 seconds, the robot
and the wire are traveling at the same speed (the LVDT is stationary). At 2 seconds the robot has
stopped but the wire continues to feed (pushing into the LVDT produces a negative velocity).
This plot shows that the movements are not synchronous but rather sequential.
Conclusions/Further Research
Dynamics characterization of the EBF3 system revealed the need for a better control method for
the robotic movements. Better programming methods produced smoother dynamics, and more
control ove r d ynamics s implifies t he r equirements f or a closed l oop c ontrol s ystem f or t his
process. Further investigation into the synchronization of the wire feed and robot will likely lead
to be tter bui ld qua lity; how ever, s ince t he G -code co mmands ar e s equential, m ore ad vanced
programming techniques will be necessary.
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