Re: MEMS gyro: offset drift



Marco Trapanese wrote:


I have an O-Navi GyroPak 3: a small module based on the Analog Devices MEMS gyroscope (ADXR150).

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When the angular rate is 0°/s the sensor output is about 2.5V. This value changes by temperature and it's different from one sensor and another.

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How to avoid this?

Yes, the MEMS accuracy is limited by the zero drift. You can pick the best parts from a pile and run those parts through the temperature offset calibration. This can improve the accuracy by several times, however nobody knows for how long this calibration will stay valid. Also, the MEMS calibration is invalidated by a mechanical or thermal stress.


I'm thinking about a nasty idea: an high-pass filter with a cutoff frequency lower than 1/100 Hz... so I can catch up everything but the long-term drift.

So, the rotation with the constant speed will not be noticed at all.

What do you think?
I guess these rate-gyro are used into RC heli: how does they works there?

Perhaps they reset zero every time the heli is on the ground.



Vladimir Vassilevsky
DSP and Mixed Signal Design Consultant
http://www.abvolt.com

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