Gait Phase Estimation Based on User–Walker Interaction Force

Pengcheng Li,Xianglong Wan,Mayu Yokoya,Kazunori Yamada,Yasuhiro Akiyama,Yoji Yamada

doi:10.3390/app11177888

Pengcheng Li, Xianglong Wan + Show 4 more

Open Access

https://doi.org/10.3390/app11177888

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Abstract

Smart walkers have been developed for assistance and rehabilitation of elderly people and patients with physical health conditions. A force sensor mounted under the handle is widely used in smart walkers to establish a human–machine interface. The interaction force can be used to control the walker and estimate gait parameters using methods such as the Kalman filter for real-time estimation. However, the estimation performance decreases when the peaks of the interaction force are not captured. To improve the stability and accuracy of gait parameter estimation, we propose an online estimation method to continuously estimate the gait phase and cadence. A multiple model switching mechanism is introduced to improve the estimation performance when gait is asymmetric, and an adaptive rule is proposed to improve the estimation robustness and accuracy. Simulations and experiments demonstrate the effectiveness and accuracy of the proposed gait parameter estimation method. Here, the average estimation error for the gait phase is 0.691 rad when the gait is symmetric and 0.722 rad when it is asymmetric.

Highlights

The number of heel strike (HS) misdetections provided by the conventional adaptive oscillators (AOs) (105 misdetections) was much larger than that provided by the proposed method (11 misdetections) for 3174 steps during the experiment with knee movement restriction
We propose a robust real-time gait phase estimation method that considers asymmetric gait patterns and relies on the user–walker interaction force
The proposed method uses two AOs (Adaptive Oscillators) that are alternately activated by a switching mechanism

Summary

Introduction

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations. Muscle strength, cognition, and coordination gradually deteriorate, possibly leading to loss of mobility [1]. Physical therapists advise elderly people to stay physically active to preserve or restore mobility [2,3]. Walkers are widely prescribed by clinicians to such patients to enlarge the base of support for improved walking stability [4]

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Discussion

Conclusion