2D trajectory estimation during free walking using a tiptoe-mounted inertial sensor

Sagawa, Koichi; Ohkubo, Kensuke

doi:10.1016/j.jbiomech.2015.03.022

Cited by 6 publications

(3 citation statements)

References 22 publications

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“…Let a three-by-three orientation matrix (OM) representing the sensor orientation with respect to the earth coordinate system be [ ] = ( ), where , and are three-by-one orthogonal unit vectors as shown in Fig. 1 (Sagawa and Ohkubo, 2015). The acceleration and angular velocity based on the earth coordinate system ( ) and ( ) are calculated from the acceleration and angular velocity based on the sensor-fixed coordinate system ( ) and ( ) using the following equations.…”

Section: Theory 21 Foot Movement Estimationmentioning

confidence: 99%

“…However, the inertial measurement system is hardly used for quantitative evaluation in medical field because measurement method using accelerometer and gyroscope are adversely affected by measurement errors and integration drifts. Furthermore, many researchers have worked on quantitative analysis of normal velocity movement utilizing inertial sensor to overcome shortcoming of the inertial sensor extensively (Mariani et al, 2010;Ojeda and Borenstein, 2007;Sagawa and Ohkubo, 2015;Yang and Li, 2012). However, few researches deal with quantitative measurement of high-speed movement like the 10 m fastest gait examination because amplitudes of acceleration and angular velocity measured are so large that they exceed the measurement range of the inertial sensors commonly used.…”

Section: Introductionmentioning

confidence: 99%

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Inertial gait analysis measurement system for large-scale health checkups

Azman

Nagai

Sagawa

et al. 2019

JAMDSM

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An inertial measurement system for estimating gait parameters indicating cognitive impairment is developed for use during large-scale health checkups. Current health checkups conduct a 10 m fastest gait examination to assess signs of cognitive impairment and physical performance. Earlier methods require examiners to follow a subject and measure the gait time using a stopwatch. The method proposed herein reduces burdens on examiners. Several gait parameters in addition to the gait time of many subjects can be measured simultaneously and quantitatively from three-dimensional foot movements estimated using inertial sensors comprising two accelerometers and two gyroscopes with different measurement range attached to both feet. Gait parameters derived from the inertial sensor are gait time, stride length, gait cycle, gait velocity, toe angle, toe height, and the percentage of swing phase. The gait condition, such as walking or running, is distinguished from the moment of toe off and heel contact of both feet. In all, 1406 subjects with ages of 19-93 years old were given instructions to walk at their highest velocity on a straight 16-m-long walking course. Mini-Mental State Examination (MMSE) is conducted on subjects. The score is used as a reference valuation of the cognitive impairment level. Experimental results show that the proposed measurement system provides equal performance to that obtained using a stopwatch and improves correlation between the MMSE score and the fastest 10 m gait time of subjects who did not run. Furthermore, it is confirmed that the proposed measurement system using inertial sensors can quantitatively provide spatiotemporal gait parameters to evaluate the physical performance in a short time during the largescale health checkups.

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Section: Theory 21 Foot Movement Estimationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Inertial gait analysis measurement system for large-scale health checkups

Azman

Nagai

Sagawa

et al. 2019

JAMDSM

Self Cite

View full text Add to dashboard Cite

show abstract

“…The WIMU2s are mounted on the upper body so that one measurement axis is visually parallel to the longitudinal axis of limbs or clavicle. The posture of inertial sensor is obtained by using acceleration, angular velocity and geomagnetic data (Yuki Ibata, 2013;Koichi Sagawa and Kensuke Ohkubo, 2015). Figure 2 shows the relationship between the global coordinate system and the sensor coordinate system.…”

Section: Configuration Of Posture Of Each Segmentmentioning

confidence: 99%