Realization of a MEMS attitude reference system for a small aerial vehicle

In general, a MEMS attitude reference system (ARS) estimates attitude (roll and pitch) of the body relative to the reference frame by implementing gyro sensors and accelerometers on all three axes. Some system using a MEMS ARS like a small aerial vehicle has one or more actuators. These actuators generate the platform vibration which acts on dynamic acceleration of accelerometers and degrade the ARS performance. Since the vibration has a time-varying frequency and occurs continuously while the vehicle is maneuvering, it cannot be isolated or attenuated by simple low pass filter. For this reason, a 2nd order infinite impulse response notch filter has been designed and the filter coefficients have been adjusted based on the least mean square method so as to identify and reject the unknown time-varying vibration frequency. To evaluate the designed MES ARS, it has been mounted on the small quad-rotor helicopter and some experimental results of attitude estimation are given.