Transfer Function Compensation in Gyroscope-Free Inertial Measurement Units for Accurate Angular Motion Sensing

Gyroscope-free inertial measurement units have been gaining popularity in applications such as motion sensing of handheld microsurgical instruments. Various accelerometer placement configurations have been proposed in the past. However, the effect of nonidentical transfer functions of accelerometers on the accuracy of angular motion sensing has been underestimated and never been taken into consideration. In this letter, significant effect of different phases at different accelerometer outputs due to nonidentical transfer functions on the accuracy is highlighted, and a method is proposed to make the transfer functions of all the accelerometers identical. Effectiveness of the method is confirmed with an experiment using ADXL-203 accelerometers.