Accelerometer Placement of the Gyroscope Reduced Inertial Measurement Unit for Measuring Six Degrees of Freedom Motion

In this paper, an accelerometers placement method of the gyro-reduced inertial measurement unit (GR-IMU) for measuring 6 degrees of freedom motion is proposed. The placed accelerometers using the proposed method can measure tangential acceleration or centripetal acceleration. Angular velocities are estimated from these accelerometer outputs using the angular velocity differential equation, algebraic equation, or Kalman filter. In order to show the usefulness of the proposed accelerometer placement method of the GR-IMU, performance evaluation was carried out. The performance evaluation results show that the angular velocity of the gyroscope-free axis can obtained by the proposed accelerometer placement method of the GR-IMU. It is confirmed that the error of the angular velocity from the angular velocity differential equation increase as time goes due to the accelerometer error. And error of the angular velocity from the algebraic equation is constant. It can also be seen from the results that the method, in which the Kalman filter is used, provides the most accurate angular velocity.