Embedding Shape Memory Alloy Actuators in Miniature Articulating Polymer Structures Using In-Mold Assembly

摘要

Fabrication and assembly of highly articulating structures has been a challenge for manufacturing engineers for several years.rnThis challenge is further enhanced when the structures are in the miniature size scales. As part of our previous work, we haverndeveloped a process called in-mold assembly to tackle this challenging manufacturing and assembly task. However, attachingrnthe actuators to such miniature structures remains a challenging task and can be expensive in terms of costs. In this work, wernwill demonstrate a single step in-mold assembly method to fabricate miniature multi degree of freedom (DOF) mechanicalrndevices with embedded SMA actuators. We have developed design optimization methods to shield the SMA actuators fromrnthe thermal cycles seen during the injection molding process. This is done to minimize thermal impact on the SMA actuatorsrnduring embedding in in-mold assembled articulating joints. We have also developed experimental methods to calibrate thernforce and position of the embedded SMA actuators with respect to temperature. Our experimental results indicate that thernSMA behavior is very repeatable with respect to temperature. Hence temperature can be used as a sensory feedback forrnposition and force control. Using the approaches developed as part of this work, we have successfully fabricated an in-moldrnassembled multi DOF miniature robot with embedded SMA actuators.