Wearable Anemometer With Multi-Sensing of Wind Absolute Orientation, Wind Speed, Attitude, and Heading

This paper presents a wearable anemometer for detecting wind absolute orientation and wind speed, as well as attitude and heading angles by incorporating a micro homemade thermal flow vector sensor with commercial triaxial micro accelerometer and triaxial micro magnetometer. The thermal flow vector sensor is comprised of three roundabout Pt hot-films uniformly distributed in a circle that is fabricated on a polyimide substrate. The flow sensor detects flow speed and flow relative angle in the body coordinate system, which is calculated from the heating powers of three hot-films that are operated in constant temperature difference circuits. The flow relative angle is further converted to the wind absolute orientation in the geographic coordinate system by means of the attitude and heading angle detected by using the triaxial accelerometer and triaxial magnetometer. The power consumption of the whole anemometer is about 400~500 mW under a wind blowing of 0 20 m/s. Using a rechargeable lithium battery with a capacity of 600 mAh, the anemometer can be continuously worked for about 4 h. Wind experimental results demonstrate that the root mean square (rms) error of the wind speed measurement reaches 0.17 m/s in the range of 0~18.9 m/s, the rms errors of wind relative angle and absolute orientation reach 2.79° and 3.22°, respectively, in the range of 0~360°. Attitude and heading experimental results illustrate that the rms errors of heading and roll measurements reach 0.42° and 0.15°, respectively, in the range of -180°~180°, and the rms error of pitch reaches 0.13° in the range of -90°~90°.