The microfluidics group at CWRU has demonstrated a thin film shape memory alloy actuated smart microvalve with feedback control for fluid control. A micromachined flow sensor was designed and fabricated and feedback control electronics were developed and incorporated with a TiNi microvalve to realize the system. The valve is a Titanium Nickel (TiNi) Shape Memory Alloy (SMA) thin film actuated micromachined valve capable of modulating 0–250 ml/min of airflow at 2 psi. The flow sensor used is a micromachined, anemometric type flow sensor. By simulation, the smart controller was designed using MATLAB with Simulink and realized with standard integrated circuits. The performance of the smart valve shows flow insensitivity to pressure variations across the valve. This was demonstrated by a constant flow even when the valve is subject to a change in the pressure drop across the valve. This is in contrast to the typical behavior of standard valves without flow sensing and feedback control.

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