著者

荻原 湧志 萬 礼応 大矢 晃久 川島 英之

雑誌

研究報告システムソフトウェアとオペレーティング・システム(OS) (ISSN:21888795)

巻号頁・発行日

vol.2023-OS-158, no.3, pp.1-8, 2023-02-14

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ロボット用ミドルウェアの代表格である ROS (Robot Operating System) において,Transform Library (TF) ライブラリは各座標系間の変換情報を有向森構造で管理し,効率的な座標変換情報の登録,座標変換の計算を可能にした.ROS の中核的なパッケージであるにも関わらず,TF ライブラリには次の三つの問題があることがわかった.まず,非効率な並行性制御により,TF の有向森構造へのアクセスが完全に逐次化され,アクセスするスレッドが増えるに従ってパフォーマンスが低下する問題がある (P1).次に,データの鮮度よりも時間的整合性を優先するため,座標変換を計算する際に最新のデータを参照しないという問題がある (P2).最後に,有向森構造の変更によって座標変換の計算時に意図しないエラーが生じるという問題がある (P3).本論文では,データベースの並行性制御法における 2PL 及び Silo を応用することにより,P1 と P2 を解決した.これらの手法は,読み取りのみのワークロードにおいて従来手法の最大 429 倍のスループットを示し,読み書きを組み合わせたワークロードにおいて従来手法の最大 1276 倍のデータ鮮度となることを示した.

著者

萬 礼応 谷川 あゆみ 高橋 正樹

出版者

一般社団法人 日本機械学会

雑誌

Dynamics & Design Conference

巻号頁・発行日

vol.2017, 2017

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In this paper, dual-task performance assessment robot (DAR) using projection is developed. Falling is a common problem in the growing elderly population. Fall-risk assessment systems have proven to be helpful in community-based fall prevention programs. One of the risk factors of falling is the deterioration of a person’s dual-task performance. For example, gait training, which enhances both motor and cognitive functions, is a multi-target stepping task (MTST), in which participants step on assigned colored targets. To evaluate the dual-task performance during MTST in human living space, projection mapping and robot navigation to maintain a safe distance from the participant are key technologies. Projection mapping is used to evaluate the long-distance dual-task performance, where MTST target images are displayed on the floor by the moving DAR. To evaluate the accuracy of the projected target position, experiments for MTST target projection using the moving DAR and video analysis are carried out. Additionally, to verify the validity of the MTST by the moving DAR at a constant speed, experiments with several young participants are carried out.

著者

萬 礼応 青山 朋樹 福本 貴彦 森口 智規 高橋 正樹

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.83, no.855, pp.17-00223-17-00223, 2017 (Released:2017-11-25)

参考文献数

17

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Gait measurements and physical fitness tests are carried out in the community health activities for health promotion and care prevention services in the growing elderly population. In particular, the timed up and go test (TUG) is the clinical test most often used to evaluate functional mobility in many clinical institutions or local communities. To evaluate the functional mobility during the TUG, a gait measurement system (Laser-TUG system) using a laser range sensor (LRS) has been proposed. The system tracks both legs and measures the foot contact positions to obtain walking parameters such as stride length and step length. To reduce the false tracking and improve the measurement accuracy during the turning phase of the TUG, a data association considering gait phase and a spline-based interpolation have been proposed. However, the false tracking is likely to be occurred in the elderly and the measurement accuracy during the turning phase is still deteriorated because of occlusion and inaccurate observation of legs. Therefore, this paper presents a high-accuracy gait measurement system using multiple LRSs. Using multiple LRSs is able to reduce the situation of leg occlusion. However, the measurement accuracy of leg position depends on the distance from the LRS. To improve the measurement accuracy, an integrated leg detection method by a weighted mean of the observation candidates from each LRS data based on the distance from the LRS is proposed. We confirm that the proposed leg detection method can improve the success rate of leg tracking in the elderly and measurement accuracy of the leg trajectory and walking parameters.