MEMS Skin Friction Sensor with High Response Frequency and Large Measurement Range

Area of Science:

• Aerospace Engineering
• Materials Science
• Sensor Technology

Background:

• Hypersonic wind tunnel experiments require precise skin friction measurements.
• Existing challenges include short test durations (milliseconds) and heavy loads.
• Micro-electromechanical system (MEMS) sensors offer miniature size, high sensitivity, and stability for this application.

Purpose of the Study:

• To address limitations in shock wind tunnel testing.
• To present and optimize fast readout circuits and sensor head structures for MEMS skin friction sensors.
• To improve the performance of MEMS skin friction sensors for hypersonic applications.

Main Methods:

• Fabrication of the MEMS sensor using micro-mechanical processes and visual alignment micro-assembly.
• Integration of the sensor head structure with a fast readout circuit.
• Testing and calibration using a centrifugal force equivalent method.

Main Results:

• The calibrated sensor exhibits good linearity, sensitivity, and stability.
• Measurement ranges are 0-2000 Pa with excellent performance.
• A resolution better than 10 Pa at a 3000 Hz detection frequency (0-1000 Pa range) was achieved.
• Static calibration showed repeatability and linearity better than 1%.

Conclusions:

• The optimized MEMS skin friction sensor and fast readout circuit are suitable for hypersonic wind tunnel experiments.
• The sensor demonstrates high accuracy, stability, and fast response capabilities.
• This technology advances the measurement of skin friction in demanding aerodynamic testing environments.