• Title/Summary/Keyword: Stair-stepping error

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Characteristics of Roughness of Inclined Surface Fabricated by Various Rapid Prototyping Processes (여러 가지 쾌속조형 방식의 경사면 거칠기 특성)

  • Kim, Gi-Dae
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.16 no.5
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    • pp.48-54
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    • 2007
  • Surface of rapid prototype has inevitably stair-stepping error, which is attributed to the continuous building process of 2 dimensional area. In this study, rounded edge model was established to estimate the roughness of inclined surface which has stair-stepping error. To investigate the roughness of rapid prototypes, specimens that have various surface inclinations were manufactured by various types of RP machines. As the surface inclination increased, the roughness of the specimens manufactured by SL, FDM, or LOM process decreased, which coincides with the simulation results. However, surface roughness of 3DP specimen was almost independent of the inclination. Furthermore, as the angle of surface increased, roughness of poly-jet specimen also increased, which is attributed to the frictional behavior between writing head and scanned area.

Step Length Estimation Algorithm for Firefighter using Linear Calibration (선형 보정을 이용한 구난요원의 보폭 추정 알고리즘)

  • Lee, Min Su;Ju, Ho Jin;Park, Chan Gook;Heo, Moonbeom
    • Journal of Institute of Control, Robotics and Systems
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    • v.19 no.7
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    • pp.640-645
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    • 2013
  • This paper presents a step length estimation algorithm for Pedestrian Dead Reckoning using linear calibrated ZUPT (zero velocity update) with a foot mounted IMU. The IMU consists of 3 axis accelerometer, gyro and magnetometer. Attitude of IMU is estimated using an inertial navigation algorithm. To increase accuracy of step length estimation algorithm, we propose a stance detection algorithm and an enhanced ZUPT. The enhanced ZUPT calculates firefighter's step length considering velocity error caused by sensor bias during one step. This algorithm also works efficiently at various motions, such as crawling, sideways and stair stepping. Through experiments, the step length estimation performance of the proposed algorithm is verified.