scholarly journals Experimental Evaluation of the Accuracy of Biped Model to Predict the Kinematics during Walking

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yao Zhang ◽  
Zhigang Song
Keyword(s):  
Experimental Evaluation ◽  
Sports Medicine ◽  
Experimental Results ◽  
Structural Vibration ◽  
Inertial Measurement Units ◽  
Step Frequency ◽  
Engineering Applications ◽  
Inertial Measurement ◽  
Measurement Units ◽  
Research Studies

Biped models (BMs) have extensive applications in structural vibration, robotics, and sports medicine, but the differences between the walking kinematics simulated by the BM model and those measured through an experiment have not been comprehensively recognized. This paper used wireless inertial measurement units (IMUs) to monitor the acceleration of center of masses (COMs) of 6 volunteers walking under the conditions of natural and fixed-knee gait. The observations were compared with the simulations from two typical BMs and also with the measurements from former research studies. The results show that when the step frequency is lower than 2.0 Hz, the peaks of acceleration simulated by BM are close to those observed in experiments and the errors are acceptable, while the step frequency is higher than 2.0 Hz, the discrepancy between the numerical and the experimental results is increasingly larger with higher step frequencies, and the errors can reach 60% at most. The comparison between numerical and experimental results indicates that the knee-fixing assumption of BMs may lead to overestimating the peaks of accelerations, but this assumption fails to explain the different increasing rates with respect to step frequency. Further research studies about the accuracy of BMs and relative modification methods are expected for civil engineering applications.

Development of an Intraoral Interface for Human-Ability Extension Robots

2016 ◽  
Vol 28 (6) ◽  
pp. 819-829 ◽  
Author(s):  
Uori Koike ◽  
◽  
Guillermo Enriquez ◽  
Takanobu Miwa ◽  
Huei Ee Yap ◽  
...  
Keyword(s):  
Human Body ◽  
Experimental Evaluation ◽  
Degrees Of Freedom ◽  
Body Movement ◽  
Ease Of Use ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Extension System ◽  
Human Ability ◽  
Measurement Units

[abstFig src='/00280006/05.jpg' width='300' text='The headset type intraoral interface' ] An extra degree of freedom to human body movement could assist people in a variety of tasks. To this end, we have previously proposed a human-ability extension system through a supernumerary limb. The system comprises of a manipulator that acts as a third arm, a feedback device that displays its status, and an interface that allows for its hands-free operation. Herein, we present this novel, intraoral interface that utilizes tongue motions and expiratory pressure. In contrast to the conventional intraoral interfaces that suffer from a lack of degrees of freedom and stability, our advanced interface is equipped with inertial measurement units and a pressure sensor to solve these problems without sacrificing the ease of use. The proposed interface is utile not only in our ongoing “Third Arm” project, but also in various other applications. We conclude with experimental evaluation of the system’s usability and its efficacy for human-ability extension systems.

Investigation of Orientation Estimation of Multiple IMUs

2020 ◽  
pp. 1-9
Author(s):  
Simone A. Ludwig
Keyword(s):  
Execution Time ◽  
Parallel Implementation ◽  
Low Cost ◽  
Research Work ◽  
Ground Truth ◽  
Experimental Results ◽  
Euler Angles ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Measurement Units

Inertial Measurement Units (IMUs) were first applied to aircraft navigation and large devices in the 1930s. At that time their application was restricted because of constraints such as size, cost, and power consumption. In recent years, however, Micro-electromechanical (MEMS) IMUs were introduced with very favorable features such as low cost, compactness, and low processing power. One of the disadvantages of these low cost IMU sensors is that the accuracy is lower compared to high-end sensors. However, past experimental results have shown that redundant Magnetic and Inertial Measurement Units (MIMUs) improve navigation performance such as for unmanned air vehicles. Even though past simulation and experimental results demonstrated that redundant sensors improve the navigation performance, however, none of the current research work offers information as to how many sensors are required in order to meet a certain accuracy. This paper evaluates different numbers of sensor configurations of an MIMU sensor array using a simulation environment. Differently rotated MIMU sensors are incrementally added and the Madgwick filter is used to estimate the Euler angles of foot mounted MIMU data. The evaluation measure used is the root mean square error (RMSE) based on the Euler angles as compared to the ground truth. During the experiments it was noticed that the execution time with increasing number of sensors increases exponentially, and thus, the parallelization of the code was designed and implemented, and run on a multi-core machine. Thus, the speedup of the parallel implementation was evaluated. The findings using the parallel version with 16 sensors are that the execution time is less than twice the execution time of having only 1 sensor and 24 times less than using the sequential version with the added benefit of a 26% increase in accuracy.

scholarly journals Analysis of ergonomic and unergonomic human lifting behaviors by using Inertial Measurement Units

2017 ◽  
Vol 3 (1) ◽  
pp. 7-10 ◽  
Author(s):  
Jan Kuschan ◽  
Henning Schmidt ◽  
Jörg Krüger
Keyword(s):  
Quality Of Life ◽  
Machine Learning ◽  
Angular Velocity ◽  
Musculoskeletal System ◽  
Occupational Diseases ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Measurement Units ◽  
Main Components

Abstract:This paper presents an analysis of two distinct human lifting movements regarding acceleration and angular velocity. For the first movement, the ergonomic one, the test persons produced the lifting power by squatting down, bending at the hips and knees only. Whereas performing the unergonomic one they bent forward lifting the box mainly with their backs. The measurements were taken by using a vest equipped with five Inertial Measurement Units (IMU) with 9 Dimensions of Freedom (DOF) each. In the following the IMU data captured for these two movements will be evaluated using statistics and visualized. It will also be discussed with respect to their suitability as features for further machine learning classifications. The reason for observing these movements is that occupational diseases of the musculoskeletal system lead to a reduction of the workers’ quality of life and extra costs for companies. Therefore, a vest, called CareJack, was designed to give the worker a real-time feedback about his ergonomic state while working. The CareJack is an approach to reduce the risk of spinal and back diseases. This paper will also present the idea behind it as well as its main components.

scholarly journals Inertial measurement units to estimate drag forces and power output during standardised wheelchair tennis coast-down and sprint tests

2021 ◽  
pp. 1-19
Author(s):  
Thomas Rietveld ◽  
Barry S. Mason ◽  
Victoria L. Goosey-Tolfrey ◽  
Lucas H. V. van der Woude ◽  
Sonja de Groot ◽  
...  
Keyword(s):  
Power Output ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Drag Forces ◽  
Measurement Units

scholarly journals Measurement of respiratory rate with inertial measurement units

2020 ◽  
Vol 6 (3) ◽  
pp. 237-240
Author(s):  
Simon Beck ◽  
Bernhard Laufer ◽  
Sabine Krueger-Ziolek ◽  
Knut Moeller
Keyword(s):  
Air Pollution ◽  
Respiratory Rate ◽  
Frequency Analysis ◽  
Clinical Settings ◽  
Breathing Rate ◽  
Demographic Changes ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Respiratory Parameters ◽  
Measurement Units

AbstractDemographic changes and increasing air pollution entail that monitoring of respiratory parameters is in the focus of research. In this study, two customary inertial measurement units (IMUs) are used to measure the breathing rate by using quaternions. One IMU was located ventral, and one was located dorsal on the thorax with a belt. The relative angle between the quaternion of each IMU was calculated and compared to the respiratory frequency obtained by a spirometer, which was used as a reference. A frequency analysis of both signals showed that the obtained respiratory rates vary slightly (less than 0.2/min) between the two systems. The introduced belt can analyse the respiratory rate and can be used for surveillance tasks in clinical settings.

scholarly journals Camera and inertial sensor fusion for the PnP problem: algorithms and experimental results

2021 ◽  
Vol 32 (4) ◽  
Author(s):  
Luigi D’Alfonso ◽  
Emanuele Garone ◽  
Pietro Muraca ◽  
Paolo Pugliese
Keyword(s):  
Pose Estimation ◽  
Good Accuracy ◽  
Inertial Sensor ◽  
Experimental Tests ◽  
Inertial Measurement Units ◽  
Magnetic Vector ◽  
Inertial Measurement ◽  
The Earth ◽  
Measurement Units ◽  
Position And Orientation

AbstractIn this work, we face the problem of estimating the relative position and orientation of a camera and an object, when they are both equipped with inertial measurement units (IMUs), and the object exhibits a set of n landmark points with known coordinates (the so-called Pose estimation or PnP Problem). We present two algorithms that, fusing the information provided by the camera and the IMUs, solve the PnP problem with good accuracy. These algorithms only use the measurements given by IMUs’ inclinometers, as the magnetometers usually give inaccurate estimates of the Earth magnetic vector. The effectiveness of the proposed methods is assessed by numerical simulations and experimental tests. The results of the tests are compared with the most recent methods proposed in the literature.

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