scholarly journals Comparing Gait Trials with Greedy Template Matching

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3089 ◽  
Author(s):  
Aliénor Vienne-Jumeau ◽  
Laurent Oudre ◽  
Albane Moreau ◽  
Flavien Quijoux ◽  
Pierre-Paul Vidal ◽  
...  
Keyword(s):  
Template Matching ◽  
Neurological Diseases ◽  
Low Cost ◽  
Similarity Index ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Individual Comparison ◽  
Gait Features ◽  
Measurement Units

Gait assessment and quantification have received an increased interest in recent years. Embedded technologies and low-cost sensors can be used for the longitudinal follow-up of various populations (neurological diseases, elderly, etc.). However, the comparison of two gait trials remains a tricky question as standard gait features may prove to be insufficient in some cases. This article describes a new algorithm for comparing two gait trials recorded with inertial measurement units (IMUs). This algorithm uses a library of step templates extracted from one trial and attempts to detect similar steps in the second trial through a greedy template matching approach. The output of our method is a similarity index (SId) comprised between 0 and 1 that reflects the similarity between the patterns observed in both trials. Results on healthy and multiple sclerosis subjects show that this new comparison tool can be used for both inter-individual comparison and longitudinal follow-up.

scholarly journals Testing of the Possibilities of Using IMUs with Different Types of Movements

2014 ◽  
Vol 12 ◽  
pp. 61-66 ◽  
Author(s):  
Pavol Kajánek
Keyword(s):  
Inertial Navigation System ◽  
Low Cost ◽  
Indoor Navigation ◽  
Integrated System ◽  
Test Results ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Improve Accuracy ◽  
Different Types ◽  
Measurement Units

Inertial navigation system (INS) is a self-contained navigation technique. Its main purpose is to determinate the position and the trajectory of the object´s movement in space. This technique is well represented not only as a supplementary method (GPS/INS integrated system) but as an autonomous system for navigation of vehicles and pedestrians, also. The aim of this paper is to design a test for low-cost inertial measurement units. The test results give us information about accuracy, which determine the possible use in indoor navigation or other applications. There are described some methods for processing the data obtained by inertial measurement units, which remove noise and improve accuracy of position and orientation.

POF-IMU sensor system: A fusion between inertial measurement units and POF sensors for low-cost and highly reliable systems

2018 ◽  
Vol 43 ◽  
pp. 82-89 ◽  
Author(s):  
Arnaldo G. Leal-Junior ◽  
Laura Vargas-Valencia ◽  
Wilian M. dos Santos ◽  
Felipe B.A. Schneider ◽  
Adriano A.G. Siqueira ◽  
...  
Keyword(s):  
Low Cost ◽  
Sensor System ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
System A ◽  
Reliable Systems ◽  
Measurement Units

scholarly journals On Using Inertial Measurement Units for Solving the Direct Kinematics Problem of Parallel Mechanisms

Robotics ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 99
Author(s):  
Stefan Schulz
Keyword(s):  
Low Cost ◽  
Parallel Mechanisms ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Sensor Structure ◽  
Prismatic Joints ◽  
Measurement Units ◽  
Linear Actuators ◽  
Achievable Accuracy ◽  
Direct Kinematics

In this paper, we investigate the accuracy and the computational efficiency of an IMU-based approach for solving the direct kinematics problem of parallel mechanisms with length-variable linear actuators under dynamic conditions. By avoiding to measure the linear actuators’ lengths and by using orientations instead, a comprehensive, low-cost sensor structure can be obtained that provides a unique solution for the direct kinematics problem. As a representative example, we apply our approach to the planar 3-RPR parallel mechanism, where P denotes active prismatic joints and R denotes passive revolute joints, and investigate the achievable accuracy and robustness on a specially designed experimental device. In this context, we also investigate the effect of sensor fusion on the achievable accuracy and compare our results with those obtained from linear actuators’ lengths when the Newton-Raphson algorithm is used to compute the manipulator platform’s pose iteratively. Finally, we discuss the applicability of inertial measurement units (IMUs) for solving the direct kinematics problem of parallel mechanisms.

scholarly journals Technology in Rehabilitation: Evaluating the Single Leg Squat Exercise with Wearable Inertial Measurement Units

2017 ◽  
Vol 56 (02) ◽  
pp. 88-94 ◽  
Author(s):  
Tomás E. Ward ◽  
Eamonn Delahunt ◽  
Brian Caulfield ◽  
Darragh F. Whelan ◽  
Martin A. O'Reilly
Keyword(s):  
Lumbar Spine ◽  
Lower Limb ◽  
Low Cost ◽  
Objective Evaluation ◽  
Inertial Measurement Units ◽  
Lower Limb Injury ◽  
Inertial Measurement ◽  
Increased Risk ◽  
Measurement Units ◽  
Single Leg Squat

SummaryBackground: The single leg squat (SLS) is a common lower limb rehabilitation exercise. It is also frequently used as an evaluative exercise to screen for an increased risk of lower limb injury. To date athlete/patient SLS technique has been assessed using expensive laboratory equipment or subjective clinical judgement; both of which are not without shortcomings. Inertial measurement units (IMUs) may offer a low cost solution for the objective evaluation of athlete/patient SLS technique.Objectives: The aims of this study were to determine if in combination or in isolation IMUs positioned on the lumbar spine, thigh and shank are capable of: (a) distinguishing between acceptable and aberrant SLS technique; (b) identifying specific deviations from acceptable SLS technique.Methods: Eighty-three healthy volunteers participated (60 males, 23 females, age: 24.68 +/− 4.91 years, height: 1.75 +/− 0.09 m, body mass: 76.01 +/− 13.29 kg). All participants performed 10 SLSs on their left leg. IMUs were positioned on participants’ lumbar spine, left shank and left thigh. These were utilized to record tri-axial accelerometer, gyroscope and magnetometer data during all repetitions of the SLS. SLS technique was labelled by a Chartered Physiotherapist using an evaluation framework. Features were extracted from the labelled sensor data. These features were used to train and evaluate a variety of random-forests classifiers that assessed SLS technique.Results: A three IMU system was moderately successful in detecting the overall quality of SLS performance (77% accuracy, 77% sensitivity and 78% specificity). A single IMU worn on the shank can complete the same analysis with 76% accuracy, 75% sensitivity and 76% specificity. Single sensors also produce competitive classification scores relative to multi-sensor systems in identifying specific deviations from acceptable SLS technique.Conclusions: A single IMU positioned on the shank can differentiate between acceptable and aberrant SLS technique with moderate levels of accuracy. It can also capably identify specific deviations from optimal SLS performance. IMUs may offer a low cost solution for the objective evaluation of SLS performance. Additionally, the classifiers described may provide useful input to an exercise biofeed-back application.

scholarly journals Biomechanical risk factors of lower back pain in cricket fast bowlers using inertial measurement units: a prospective and retrospective investigation

2020 ◽  
Vol 6 (1) ◽  
pp. e000818
Author(s):  
Billy Senington ◽  
Raymond Y Lee ◽  
Jonathan M Williams
Keyword(s):  
Back Pain ◽  
Effect Sizes ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Time To Peak ◽  
Spinal Kinematics ◽  
History Of ◽  
Measurement Units ◽  
Lumbar Extension

ObjectivesTo investigate spinal kinematics, tibial and sacral impacts during fast bowling, among bowlers with a history of low back pain (LBP) (retrospective) and bowlers who developed LBP in the follow-up season (prospective).Methods35 elite male fast bowlers; senior (n=14; age=24.1±4.3 years; height=1.89±0.05 m; weight=89.2±4.6 kg) and junior (n=21; age=16.9±0.7; height=1.81±0.05; weight=73.0±9.2 kg) were recruited from professional county cricket clubs. LBP history was gathered by questionnaire and development of LBP was monitored for the follow-up season. Spinal kinematics, tibial and sacral impacts were captured using inertial measurement units placed over S1, L1, T1 and anteromedial tibia. Bonferroni corrected pairwise comparisons and effect sizes were calculated to investigate differences in retrospective and prospective LBP groups.ResultsApproximately 38% of juniors (n=8) and 57% of seniors (n=8) reported a history of LBP. No differences were evident in spinal kinematics or impacts between those with LBP history and those without for seniors and juniors. Large effect sizes suggest greater rotation during wind-up (d=1.3) and faster time-to-peak tibial impacts (d=1.5) in those with no history of LBP. One junior (5%) and four (29%) seniors developed LBP. No differences were evident in spinal kinematics or impacts between those who developed LBP and those who did not for seniors. In seniors, those who developed LBP had lower tibial impacts (d=1.3) and greater lumbar extension (d=1.9) during delivery.ConclusionRetrospective analysis displayed non-significant differences in kinematics and impacts. It is unclear if these are adaptive or impairments. Prospective analysis demonstrated large effect sizes for lumbar extension during bowling suggesting a target for future coaching interventions.

scholarly journals Benchmarking low-cost inertial measurement units for indoor localisation and navigation of AGVs

Procedia CIRP ◽  
2019 ◽  
Vol 86 ◽  
pp. 204-209 ◽  
Author(s):  
Martijn Cramer ◽  
Jeroen Cramer ◽  
David De Schepper ◽  
Peter Aerts ◽  
Karel Kellens ◽  
...  
Keyword(s):  
Low Cost ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Measurement Units ◽  
Indoor Localisation

scholarly journals Design of a pen-shaped input device using the low-cost inertial measurement units

2003 ◽  
Vol 13 (2) ◽  
pp. 247-258 ◽  
Author(s):  
Wook Chang ◽  
Kyoung-Ho Kang ◽  
Eun-Seok Choi ◽  
Won-Chul Bang ◽  
Alexy Potanin ◽  
...  
Keyword(s):  
Low Cost ◽  
Input Device ◽  
Inertial Measurement Units ◽  
Inertial Measurement ◽  
Measurement Units

scholarly journals Particle Imaging Velocimetry Gyroscope

Sensors ◽  
2019 ◽  
Vol 19 (21) ◽  
pp. 4734
Author(s):  
Ahmed A. Youssef ◽  
Naser El-Sheimy
Keyword(s):  
Signal To Noise Ratio ◽  
Low Cost ◽  
Particle Imaging Velocimetry ◽  
High Signal ◽  
Inertial Measurement Units ◽  
Signal To Noise ◽  
Inertial Measurement ◽  
Measurement Units ◽  
Particle Imaging ◽  
Bias Instability

Inertial measurement units (IMUs) are typically classified as per the performance of the gyroscopes within each system. Consequently, it is critical for a system to have a low bias instability to have better performance. Nonetheless, there is no IMU available commercially that does not actually suffer from bias-instability, even for the navigation grade IMUs. This paper introduces the proposition of a novel fluid-based gyroscope, which is referred to hereafter as a particle imaging velocimetry gyroscope (PIVG). The main advantages of the PIVG include being nearly drift-free, a high signal-to-noise ratio (SNR) in comparison to commercially available high-end gyroscopes, and its low cost.

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