A high resolution tilt measurement system based on multi-accelerometers

In this paper, a wireless tilt measurement system of high resolution is proposed and demonstrated using multiple MEMS (Micro-electromechanical Systems) accelerometers. The measurement system is mainly composed of MEMS accelerometers as sensing unit, a MCU (Micro Controller Unit), wireless transceivers, battery and a PC terminal. Three MEMS accelerometers are purposely located with specific orientations and the system output is determined from the accelerometer that is most sensitive in the tilting range of the object under testing. The raw measured signal collected by the MCU is processed using Kalman Filter (KF) and the analyzed data is transmitted to the PC terminal by a wireless module. The effect of different KF parameters are analyzed using the Allan variance. After eliminating the accelerometers' installation errors, the measuring resolution of system is found to be 0.02° in the whole range from 0° to 360°. In the step test of tilting back and forth, it is found that the absolute measurement error is less than 0.004° for the step change of 0.05°.