There are documented schemes for balancing 2 wheeled segway type robots using a gyro plus an accelerometer with either a complementary or Kalman filter. I have also found schemes using a gyro plus wheel encoders.
Is it possible to balance a two wheeled robot using only a MEMS gyro (no accelerometer, no wheel encoders, no Kalman filter, no complementary filter)? If yes, how? If no, why not? Do you have supporting data?