A Biologically Inspired Wet Shape Memory Alloy Actuated Robotic Pump

This paper presents the concept, design, optimization, and experimental analysis of a biologically inspired wet shape memory alloy (SMA) actuated pump for robotic and mechatronic systems. Just as the human heart provides energy to the muscles in the body, the robotic SMA pump distributes thermofluidic energy to arrays of SMA actuators that function as robotic muscles. Furthermore, the robotic pump draws from its own fluidic output to assist in the actuation of its own internal SMA actuators, just as a portion of the blood pumped by the human heart supplies energy to its own muscles. A feasibility analysis provides insight to limits of configuration parameters. Through dynamic modeling and simulation of the system, various configurations can be analyzed for optimization of the output. The effects of changing configuration parameters were explored via simulation and validated with experimentation. The current prototype of the SMA heart is capable of pumping 2.1 times more fluid than is required to sustain its own actuation. This is the first successful implementation of such a robotic pump, such that it has a net positive thermofluidic output to provide to other actuators while sustaining its own actuation via thermofluidic feedback. Furthermore, this SMA pump is capable of pumping a net output of 66 mL/min, which is two orders of magnitude larger than the output of any other SMA pump.