  This paper presents an efficient servomotor-aided calibration method for the
triaxial gyroscope. The entire calibration process only takes about one minute,
and high-precision equipment is not used. The main idea of this method is that
the measurement of the gyroscope should equal to the rotation speed of the
servomotor. A six-observation experimental design is proposed to minimize the
maximum variance of the estimated scale factors and biases. Besides, a fast
converged recursive linear least square estimation method is presented to
reduce computational complexity. The simulation results specify the robustness
under normal and extreme condition. We experimentally demonstrate the
achievability of the proposed method on a robot arm and implements the method
on a microcontroller. The calibration results of the proposed method are
verified by comparing with a traditional turntable method, and the experiment
indicates that the error between these two methods is less than $10^{-3}$. By
comparing the calibrated low-cost gyroscope reading with the reading from a
high-precision gyroscope, we can infer that our method significantly increases
the accuracy of the low-cost gyroscopes.
