2 research outputs found
Adaptive Cardinal Heading Aided for Low Cost Foot-Mounted Inertial Pedestrian Navigation
The use of a low-cost MEMS-based Inertial Measurement Unit (IMU) provides a cost-effective approach for navigation purposes. Foot-mounted IMU is a popular option for indoor inertial pedestrian navigation, as a small and light MEMS-based inertial sensor can be tied to a pedestrian's foot or shoe. Without relying on GNSS or other external sensors to enhance navigation, the foot-mounted pedestrian navigation system can autonomously navigate, relying solely on the IMU. This is typically performed with the standard strapdown navigation algorithm in a Kalman filter, where Zero Velocity Updates (ZVU) are used together to restrict the error growth of the low-cost inertial sensors. ZVU is applied every time the user takes a step since there exists a zero velocity condition during stance phase. While velocity and correlated attitude errors can be estimated correctly using ZVUs, heading error is not because it is unobservable. In this paper, we extend our previous work to correct the heading error by aiding it using Multiple Polygon Areas (MPA) with adaptive weighting factor. We termed the approach as Adaptive Cardinal Heading Aided Inertial Navigation (A-CHAIN). We formulated an adaptive weighting factor applied to measurement noise to enhance measurement confidence. We then incorporated MPA heading into the algorithm, whereas multiple buildings with the same orientation are grouped together and assigned a specific heading information as a priori. Results shown that against the original CHAIN, the proposed Adaptive-CHAIN improved the position accuracy by more than five-fold
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The Relationship Between Force Plate Derived Eccentric Rate of Force Development and ELEIKO Vmaxpro Derived Eccentric Motion Rate of Force Development
Eccentric rate of force development (ECC RFD) is a measure of the rate at which muscles can generate decelerative forces. However, it has traditionally been measured while jumping on force plates, which are not easily accessible or easy to use in a practical setting. With technology advancements it may be possible to measure ECC RFD in more practical settings. An inertial measurement unit (IMU) such as the ELEIKO Vmaxpro IMU, which are IMUs embedded at the end of a barbell, may provide practitioners the ability measure ECC RFD without force plates. Vmaxpro calls their variable specifically peak ECC motion RFD (peak ECC mRFD). However, the relationship between force plate derived ECC RFD and ELEIKO Vmaxpro derived ECC mRFD is unknown. Twenty-one male participants performed maximum effort weighted countermovement jumps (wCMJs) with a 20kg ELEIKO barbell with Vmaxpro IMUs on a dual force plate. Both average and peak ECC RFD were calculated for each jump from the force plate data, whereas peak ECC mRFD was calculated from the ELEIKO Vmaxpro IMU. Force plate derived average ECC RFD was calculated as the slope of the line of best fit over the entire eccentric phase. Both force plate derived peak ECC RFD and Vmaxpro peak ECC mRFD were calculated as the slope of 40 ms continuous intervals over the entire eccentric phase. The trial producing peak jump height derived from the force plate was used for analysis. Pearson correlation coefficients and simple linear regressions were calculated between average ECC RFD and Vmaxpro peak ECC mRFD, as well as between peak ECC RFD and Vmaxpro peak ECC mRFD. Of the 99 trials collected, 44% were unable to be used due to missing data from Vmaxpro including all trials from one participant, which left 20 participants in the final analyses. Very large, positive correlations were observed between force plate average ECC RFD and peak ECC mRFD (r = 0.71), as well as force plate peak ECC RFD and peak ECC mRFD (r = 0.80). Both linear regressions were found to be statistically significant (p < 0.005). A goal of this study was to find an alternative way of tracking ECC RFD in a practical setting other than using force plates. Although this study demonstrates a promising future for the use ELEIKO Vmaxpro IMUs to measure ECC RFD, due to the high number of missed trials, caution is suggested when using this device in a practical setting