15 research outputs found

    A Smart Safety Helmet using IMU and EEG sensors for analysis of worker’s fatigue

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    It is known that head gesture and mental states can reflect some human behaviors related to a risk of accident when using machine-tools. The research works presented in this paper aim to reduce the number of injury and thus increase worker safety. Instead using camera, this paper presents a Smart Safety Helmet (SSH) in order to track head gestures and mental states of worker able to recognize anomalous behavior. Information extracted from SSH is used for computing risk level of accident (a safety level) for preventing and reducing injury or accidents. The SSH system is an inexpensive, non-intrusive, non-invasive, and non-vision-based system, which consists of 9DOF Inertial Measurement Unit (IMU) and dry EEG electrodes. A haptic device, such as vibrotactile motor, is integrated to the helmet in order to alert the operator when computed risk level (fatigue, high stress or error) reach a threshold. Once the risk level of accident breaks the threshold, a signal will be sent wirelessly to stop the relevant machine tool or process

    触覚フィードバックを用いた体性感覚の操作

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    人間が自らの肉体に対して持つ興味は大きい.多くの人間は体力的・知能的・美的な面で他の人間よりも優れた肉体を欲すると考えられ,また様々な特殊な体を持つ空想上のキャラクターに憧れ人間とは異なる構造の身体に興味を持つ物も多いであろう.だが身体機能の向上のためには通常長期間の継続した訓練を必要とし,人間とは異なる身体への変身は不可能であるといえる.科学技術の発展に伴い肉体形状および運動機能への物理的な介入方法が広まりつつあるが,未だに身体的リスクと金銭的コストが高く,複雑な装置を必要とするため誰もが気軽に利用できるものではない.このような背景から本研究では,人間の肉体そのものに介入するのではなく,肉体が生成する感覚である体性感覚を肉体外部から操作することで肉体の主観的特性を操作することを目標とする.主に身体表面の感覚を刺激するアクチュエータとして広く使われているボイスコイル型振動子は,様々な触感の呈示を簡便なセットアップで実現できる.したがってこれを身体運動に同期させて駆動する振動フィードバックシステムを開発し,運動に伴って発生する身体内部の感覚を操作することを試みる.体性感覚の操作に関する本研究は2 つの戦略によって構成される.一つは体性感覚の「増強」である.これは自己身体運動を把握する能力を高め,より鮮明に,あるいは詳細に運動状態を知覚させる量的な操作である.一方で,もう一つの戦略は体性感覚の質的な操作である「変調」である.これは身体自体の硬さや重さといった特性を変化させることであり,結果として身体を構成する材質・構造を主観的に変調することになる.これら2 つの戦略に沿った具体的な手法を,体性感覚の増強に関して2 件,変調に関しても2件設計した.体性感覚の増強に関しては,第一にロータリスイッチの回転に伴うカチカチとした触覚・力覚フィードバック「カチカチ感」に着目した.これを肘関節に付与して運動時の体性感覚を鮮明化し,腕立て伏せ姿勢の教示を試みた(第3 章).第二に,自動車運転におけるアクセルペダルの操作を補助するため,ペダルの角度が一定値変化する度に瞬間的なクリック振動を呈示することで,ペダル角度の把握能力向上および操作性向上を試みた(第4 章).体性感覚の変調に関しては,第一に様々な材質の衝突振動を再現する減衰正弦波モデルに着目し,これを身体運動に同期させて呈示することで身体材質感の変調を試みた(第5 章).これによりロボットやゴム人間といった特殊なキャラクターの体性感覚の再現を目指した.第二に,ロボットキャラクターのみに着目し,実際のロボットに生じる振動加速度を記録・モデリング・再生する手法によりロボットの内部構造に起因する体性感覚まで再現することを試みた(第6 章).またロボット感体験の総合的なリアリティ向上のため高品質な視覚・聴覚刺激を組み合わせたバーチャルリアリティゲームを開発した.また体性感覚の操作をより広範囲で行うため,既存の触覚ディスプレイの問題点を考察し,身体広範囲に均等な触覚刺激を呈示する触覚ディスプレイを開発した(第7 章).最後に本研究全体のまとめと結論を述べ,今後の展望を示す(第8 章).電気通信大学201

    Soft Pneumatic Actuator Skin with Piezoelectric Sensors for Vibrotactile Feedback

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    The latest wearable technologies demand more intuitive and sophisticated interfaces for communication, sensing, and feedback closer to the body. Evidently, such interfaces require flexibility and conformity without losing their functionality even on rigid surfaces. Although there have been various research efforts in creating tactile feedback to improve various haptic interfaces and master–slave manipulators, we are yet to see a comprehensive device that can both supply vibratory actuation and tactile sensing. This paper describes a soft pneumatic actuator (SPA)-based skin prototype that allows bidirectional tactile information transfer to facilitate simpler and responsive wearable interface. We describe the design and fabrication of a 1.4 mm-thick vibratory SPA – skin that is integrated with piezoelectric sensors. We examine in detail the mechanical performance compared to the SPA model and the sensitivity of the sensors for the application in vibrotactile feedback. Experimental findings show that this ultra-thin SPA and the unique integration process of the discrete lead zirconate titanate (PZT)-based piezoelectric sensors achieve high resolution of soft contact sensing as well as accurate control on vibrotactile feedback by closing the control loop

    Development and Testing of A Wearable Vibrotactile Haptic Feedback System For Proprioceptive Rehabilitation

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    The human sense of touch is an integral part of daily life. For tasks involving grasping and manipulation of objects, force feedback is a key requirement. Most of the systems give contact point or complete grasping force feedback; for precision grasping and other physical interactions, finger awareness and force feedback from independent fingers is essential. In this study a novel, wearable proprioceptive rehabilitation system is designed which restores the ability of identifying and distinguishing between individual fingers of a prosthetic hand or an exoskeleton in a non-invasive manner. Moreover, it provides different levels of force feedback from every finger as well, which enables the user to distinguish and control force in precision grasping activities. For testing the system accuracy, classical psychophysical methods were used on a group of 14 voluntary disabled subjects. The tests were conducted in both, ideal and real-world conditions i.e. without and with distractions and accuracies were calculated accordingly. A p-test was also conducted to observe significance between the samples of with and without distraction datasets. The system performed with an overall accuracy of 82.04% which was well above the min. performance measure of 60%. Vi-HaB is standalone system and can be mounted on any upper limb rehabilitation (prosthesis, exoskeleton) system for finger awareness and force feedback

    Crowd Navigation in VR: exploring haptic rendering of collisions

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    International audienceVirtual reality (VR) is a valuable experimental tool for studying human movement, including the analysis of interactions during locomotion tasks for developing crowd simulation algorithms. However, these studies are generally limited to distant interactions in crowds, due to the difficulty of rendering realistic sensations of collisions in VR. In this work, we explore the use of wearable haptics to render contacts during virtual crowd navigation. We focus on the behavioural changes occurring with or without haptic rendering during a navigation task in a dense crowd, as well as on potential after-effects introduced by the use haptic rendering. Our objective is to provide recommendations for designing VR setup to study crowd navigation behaviour. To this end, we designed an experiment (N=23) where participants navigated in a crowded virtual train station without, then with, and then again without haptic feedback of their collisions with virtual characters. Results show that providing haptic feedback improved the overall realism of the interaction, as participants more actively avoided collisions. We also noticed a significant after-effect in the users' behaviour when haptic rendering was once again disabled in the third part of the experiment. Nonetheless, haptic feedback did not have any significant impact on the users' sense of presence and embodiment

    Cooperative Navigation for Mixed Human–Robot Teams Using Haptic Feedback

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    In this paper, we present a novel cooperative navigation control for human–robot teams. Assuming that a human wants to reach a final location in a large environment with the help of a mobile robot, the robot must steer the human from the initial to the target position. The challenges posed by cooperative human–robot navigation are typically addressed by using haptic feedback via physical interaction. In contrast with that, in this paper, we describe a different approach, in which the human–robot interaction is achieved via wearable vibrotactile armbands. In the proposed work, the subject is free to decide her/his own pace. A warning vibrational signal is generated by the haptic armbands when a large deviation with respect to the desired pose is detected by the robot. The proposed method has been evaluated in a large indoor environment, where 15 blindfolded human subjects were asked to follow the haptic cues provided by the robot. The participants had to reach a target area, while avoiding static and dynamic obstacles. Experimental results revealed that the blindfolded subjects were able to avoid the obstacles and safely reach the target in all of the performed trials. A comparison is provided between the results obtained with blindfolded users and experiments performed with sighted people
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