Original scientific paper
https://doi.org/10.1080/00051144.2019.1690290
Method for joint flexion angle estimation using UWB ranging with clock model compensation
Hrvoje Mihaldinec
; Faculty of Electrical Engineering and Computing, Department of Electronic Systems and Information Processing, University of Zagreb, Zagreb, Croatia
Hrvoje Dzapo
; Faculty of Electrical Engineering and Computing, Department of Electronic Systems and Information Processing, University of Zagreb, Zagreb, Croatia
Abstract
This paper presents a wearable system for measurement and monitoring human body joint angles based on UWB ranging. The DW1000 chip was used with standard deviation of distance measurement within 10 cm with range up to 70 m. We propose a method for enhancing range measurement accuracy based on an estimator which compensates clock imperfections and relative pairwise movement of nodes. Since the estimator is valid only for small slices of time, we propose continuous motion estimation algorithm based on segment-by-segment data processing and stitching results into a final solution. The pairwise distances are approximated with Taylor series of a given order L in short measurement windows while timestamps are compensated with clock parameters of a first-order clock model. The main contribution of the proposed method is the ability to implement joint angle estimation by using low-cost off-the-shelf UWB components, without high-precision clock sources or a need for wired or wireless time synchronization. In order to determine an optimum order L and time slice length, Sprague and Geers' metric was used. The method was experimentally evaluated in static and dynamic conditions. The results show that the accuracy of the proposed system is comparable to similar solutions based on laboratory equipment.
Keywords
Ultrawideband (UWB); ranging; joint angle estimation; time-range model; clock model; DW1000
Hrčak ID:
239858
URI
Publication date:
3.12.2019.
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