Improved Extended Kalman Filter-Based Disturbance Observers for Exoskeletons

Fuente: arXiv
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Autori principali: Li, Shilei, Shi, Dawei, Iwasaki, Makoto, Ning, Yan, Zhou, Hongpeng, Shi, Ling
Natura: Preprint
Pubblicazione: 2025
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author Li, Shilei
Shi, Dawei
Iwasaki, Makoto
Ning, Yan
Zhou, Hongpeng
Shi, Ling
author_facet Li, Shilei
Shi, Dawei
Iwasaki, Makoto
Ning, Yan
Zhou, Hongpeng
Shi, Ling
contents The nominal performance of mechanical systems is often degraded by unknown disturbances. A two-degree-of-freedom control structure can decouple nominal performance from disturbance rejection. However, perfect disturbance rejection is unattainable when the disturbance dynamic is unknown. In this work, we reveal an inherent trade-off in disturbance estimation subject to tracking speed and tracking uncertainty. Then, we propose two novel methods to enhance disturbance estimation: an interacting multiple model extended Kalman filter-based disturbance observer and a multi-kernel correntropy extended Kalman filter-based disturbance observer. Experiments on an exoskeleton verify that the proposed two methods improve the tracking accuracy $36.3\%$ and $16.2\%$ in hip joint error, and $46.3\%$ and $24.4\%$ in knee joint error, respectively, compared to the extended Kalman filter-based disturbance observer, in a time-varying interaction force scenario, demonstrating the superiority of the proposed method.
format Preprint
id arxiv_https___arxiv_org_abs_2510_15533
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Improved Extended Kalman Filter-Based Disturbance Observers for Exoskeletons
Li, Shilei
Shi, Dawei
Iwasaki, Makoto
Ning, Yan
Zhou, Hongpeng
Shi, Ling
Robotics
The nominal performance of mechanical systems is often degraded by unknown disturbances. A two-degree-of-freedom control structure can decouple nominal performance from disturbance rejection. However, perfect disturbance rejection is unattainable when the disturbance dynamic is unknown. In this work, we reveal an inherent trade-off in disturbance estimation subject to tracking speed and tracking uncertainty. Then, we propose two novel methods to enhance disturbance estimation: an interacting multiple model extended Kalman filter-based disturbance observer and a multi-kernel correntropy extended Kalman filter-based disturbance observer. Experiments on an exoskeleton verify that the proposed two methods improve the tracking accuracy $36.3\%$ and $16.2\%$ in hip joint error, and $46.3\%$ and $24.4\%$ in knee joint error, respectively, compared to the extended Kalman filter-based disturbance observer, in a time-varying interaction force scenario, demonstrating the superiority of the proposed method.
title Improved Extended Kalman Filter-Based Disturbance Observers for Exoskeletons
topic Robotics
url https://arxiv.org/abs/2510.15533