Abstract
Sensing angular vibration motion using only self-referencing sensors has been gaining interest in various mobile applications. An example is long distance communication and tracking tasks on motorized vehicles. There is a lack of availability of infrastructure and externally referenced sensors like position sensitive detectors are not suitable. Hence, such applications can only rely on self-referencing sensors. Gyroscope is a good candidate for such applications. However, the drawback of gyroscope is the drift after integration. Most of the conventional filtering techniques introduce phase difference and is not ideal for real-time compensation applications. Several novel band-pass that do not introduce phase difference have since been introduced. However, such zero-phase band-pass filter works well for the velocity domain, but not in the displacement whereby there is significant drift after the numerical integration. To address this, a near zero-phase filtering algorithm is proposed. The proposed method first filter the drift or voluntary motion signal in the low frequency domain with recursive least square (RLS) based adaptive modeling. Weighted Fourier linear combiner (WFLC) is then used as zero-phase band-pass filter to estimate the angular displacement. Real experimental data is collected and the results demonstrated that the proposed method out-performs several other filtering techniques.