Lower Limb Model Based Inertial Indoor Pedestrian Navigation System for Walking and Running

Wanling Li,Zhiguo Cao,Yiming Ding,Zhengchun Wang,Zhi Xiong

doi:10.1109/access.2021.3065666

Abstract

Foot-mounted inertial navigation systems are suitable in GNSS denied environment for special tasks such as fire rescue, soldier, etc. These tasks are often accompanied by vigorous movements such as running and jumping, which is a challenge for the Zero Velocity Update (ZUPT) based inertial navigation system. As the speed increases, the inertial sensor drift increases, while the zero-velocity interval shortens, making the gait detection more difficult and resulting in a limited error correction. And as the motion intensifies, the stability of the system decreases. A multi-node inertial pedestrian navigation system based on the lower limb model constraint is proposed in this paper. Our first contribution in this paper is studying a simplified adaptive zero-bias estimation algorithm. The changes in velocity and angular velocity between two steps are used to estimate and compensate for the drift of accelerometers and gyroscopes. Our second contribution is proposing a novel gait segmentation method by lower limb motion statistics feature. A hybrid detection model of dual IMU is conducted to improve the accuracy of gait recognition. After that, the maximum distance inequality constraint is studied to correct the position error when the still phase is not available in vigorous movement. The final contribution is studying the chi-square fault detection method to improve the stability of KF. Multiple experiments prove that the proposed multi-node inertial pedestrian navigation system is effective in dealing with various challenging in walking, running, and hybrid motion pedestrian inertial navigation problems which could achieve less than 0.3% average distance error.

Highlights

In recent years, the demand for indoor positioning in special tasks such as firefighting, the underground prospecting, and the location-based service is increasing gradually
The major indoor positioning methods include positioning technology based on external sources, such as WiFi, Bluetooth, Ultra Wide Band (UWB), and passive navigation, such as inertial navigation [1]
MIMU is affected by the environment, while the complex environment of special tasks and the violent movement of operators will lead to timevarying errors, so it is difficult to describe with a definitive mathematical model

Summary

INTRODUCTION

The demand for indoor positioning in special tasks such as firefighting, the underground prospecting, and the location-based service is increasing gradually. The following sections will present four parts: adaptive accelerometer and gyroscope zero bias estimation, dual IMU gait detection method, bipedal system heading initial alignment and error correction, and fault detection by dynamic Kalman Filter. This paper constructs a hybrid detection model of dual IMU for leg and foot, uses the Euclidean distance of acceleration and angular velocity for motion mode identification, and uses the statistically estimated values under dynamic motion as the still phase’s thresholds. We can be seen that the method can be adapted to different movement speeds

BIPEDAL NAVIGATION SYSTEM HEADING INITIAL ALIGNMENT AND ERROR CORRECTION

FAULT DETECTION BY DYNAMIC KALMAN FILTER

CONCLUSION