Robotic grippers that gently handle objects of various shapes are required for various applications these days. Conventional finger-shaped grippers are multifunctional and can grip various objects; however, grasping an item without... more
Robotic grippers that gently handle objects of various shapes are required for various applications these days. Conventional finger-shaped grippers are multifunctional and can grip various objects; however, grasping an item without slippage requires planning the positioning of the fingers at appropriate locations on the item. Hence, a ring-shaped soft gripper that coils itself around objects like a rubber band is suggested in this paper. The proposed gripper comprises a soft tube containing laminated sponges interleaved with plastic sheets. Evacuation of the air within the sponges shrinks them and decreases the diameter of the ring, thereby allowing the gripper to firmly hold objects. The gripper is therefore flexible enough to coil around objects of various shapes without gaps. Furthermore, the rigidity of the compressed sponges inside the gripper prevents wobbling of the gripped objects. The air within the gripper can be used to adjust the gripping force. The minimum diameter of t...
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Prior research has demonstrated that during two-alternative decision making, gaze is biased towards the alternative that is eventually chosen. The Gaze Cascade model proposed by Shimojo, Simion, Shimojo, & Scheier (2003) predicts a larger... more
Prior research has demonstrated that during two-alternative decision making, gaze is biased towards the alternative that is eventually chosen. The Gaze Cascade model proposed by Shimojo, Simion, Shimojo, & Scheier (2003) predicts a larger bias for decisions requiring one to choose the item that is liked the most versus decisions that require one to choose the item that is disliked most. More recently, Park, Shimojo and Shimojo (2010) showed that preference formation operates differently during decisions among faces and scenes, which suggests that gaze bias might differ depending on whether the decision stimuli are faces or scenes. In the present study we tested these two hypotheses in a within-subject design. Eye movements were monitored while participants (n=48) made two-alternative Like or Dislike decisions among pairs of faces or scenes. We found remarkably little influence of stimulus type on gaze bias for either decision task, which disconfirms the hypothesis that gaze bias ope...
An arrow marker appearing in a field of view shifts the observer’s attention in its indicated direction. On the other hand, the gaze of another individual not only shifts the observer’s attention but also increases the likability of... more
An arrow marker appearing in a field of view shifts the observer’s attention in its indicated direction. On the other hand, the gaze of another individual not only shifts the observer’s attention but also increases the likability of objects in the direction of their gaze. These effects occur even when arrow markers or gaze cues are presented for very short periods and the observer is unaware of them. To expand on the findings of previous studies, we conducted two experiments. The first examined the changes in likability and attentional shift induced by supraliminal and subliminal arrow markers, using 40 male and 40 female participants. It was found, contrary to previous findings, that supraliminal arrow markers not only shifted the observer’s attention but slightly increased object likability. On the other hand, subliminal arrow markers only shifted the observer’s attention. The attentional shift was stronger for female than for male participants in the case of supraliminal, but not...
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When people choose between two items, they usually look at them alternately before deciding. The frequency and duration of contact are usually determined unconsciously. However, in a previous study, looking at one item for longer than the... more
When people choose between two items, they usually look at them alternately before deciding. The frequency and duration of contact are usually determined unconsciously. However, in a previous study, looking at one item for longer than the other increased participants’ preference for the former, but only when they had to move their eyes to look at each item. This result implies that eye movements not only gather information but are also closely related to decision-making. By analogy, this study examines the relation between hand movements and haptic preference. When participants touched two handkerchiefs in a pre-determined order before choosing the one they preferred, the likelihood of choosing the more frequently touched handkerchief was greater than chance. Bias in the choice was greater with increased difference in the frequency of touching between the two handkerchiefs. It was also greater when participants moved their arm to touch the handkerchiefs, compared with when a machine...
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This paper proposes a wearable chair that reduces the burden on the lower limbs in standing and details the orthosis we developed. The wearable chair consists of a seat, thigh link, lower thigh link and a pair of shoes. These components... more
This paper proposes a wearable chair that reduces the burden on the lower limbs in standing and details the orthosis we developed. The wearable chair consists of a seat, thigh link, lower thigh link and a pair of shoes. These components are connected by pneumatic passive elements and switched from free motion to fixed position by vacuum pressure. Users can sit at any place or time by fixing the joints. The pneumatic passive elements are flexible and lightweight compared to conventional passive device. Results of experiments on walking and weight support using the chair are described.
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Conventional robot systems consist of hard mechanical elements and actuators for exerting a force to objects efficiently. These systems are taking remarkable activities in industrial field but not in daily life of human. Main disadvantage... more
Conventional robot systems consist of hard mechanical elements and actuators for exerting a force to objects efficiently. These systems are taking remarkable activities in industrial field but not in daily life of human. Main disadvantage of these robot systems is the fatal risk to human body when they lose control in the case of breakdown. On the contrary, we focus on flexible robot systems that work passively without actuators. These systems are intrinsically safe to human body since they never exert any excessive forces. In this paper, we present a novel passive element that varies its stiffness to internal vacuum pressure. This passive element is a soft vinyl tube embedded with Styrofoam beads, and is therefore soft and light contrary to conventional passive elements. Using the flexibility and the controllable stiffness, we developed a wearable haptic display that provides a sensation of elasticity and viscosity. The design of this new passive element and the applications to haptic displays are discussed.
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Research Interests: Chemistry, Analytical Chemistry, Biomedical Engineering, Data Analysis, Magnetic Resonance Imaging, and 15 moreLinear models, Biomedical Optics, Humans, Hemodynamics, Infrared spectroscopy, Female, Male, Heart rate, Forehead, Infrared, Adult, Distilled Water, Blood Vessel, Hemoglobins, and Magnetic resonance image
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A Particle Mechanical Constraint is a soft vinyl tube that envelops Styrofoam beads. It has 6 degrees-of-freedom including compression, elongation, bending and twisting. By exhausting the inside air the PMC solidifies and constraints all... more
A Particle Mechanical Constraint is a soft vinyl tube that envelops Styrofoam beads. It has 6 degrees-of-freedom including compression, elongation, bending and twisting. By exhausting the inside air the PMC solidifies and constraints all degrees-of-freedom in an arbitrary shape. The stiffness of the PMC is proportional to the inside air pressure. Viscosity is also controlled virtually by changing the inside air pressure in proportion to the speed of transformation of the PMC. By the use of a PMC, we developed a wearable haptic display that provides a sensation of contacting a wall and moving in water with viscosity. We also developed an upper-limb orthotic that constrains shoulder and elbow movements. PMC is adequate as a wearable human interface because it is light, soft and safe. In addition, it is an inherently passive device that never exerts excessive force when broken.
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Neural activity was recorded in the parietooccipital cortex while monkeys performed different tasks aimed at investigating visuomotor interactions of retinal, eye, and arm-related signals on neural activity. The tasks were arm reaching 1)... more
Neural activity was recorded in the parietooccipital cortex while monkeys performed different tasks aimed at investigating visuomotor interactions of retinal, eye, and arm-related signals on neural activity. The tasks were arm reaching 1) to foveated targets; 2) to extrafoveal targets, with constant eye position; 3) within an instructed-delayed paradigm, under both light and darkness; 4) saccadic eye movements toward, and static eye holding on peripheral targets; and 5) visual fixation and stimulation. The activity of many cells was modulated during arm reaction (68%) and movement time (58%), and during static holding of the arm in space (64%), when eye position was kept constant. Eye position influenced the activity of many cells during hand reaction (45%) and movement time (51%) and holding of hand static position (69%). Many cells (56%) were also modulated during preparation for hand movement, in the delayed reach task. Modulation was present also in the dark in 59% of cells duri...
Research Interests: Neuroscience, Electrophysiology, Animal Behavior, Biology, Neurophysiology, and 15 moreMedicine, Darkness, Reaching, Animals, Lighting, Parietal Cortex, Eye Movements, Parietal Lobe, Eye Movement, Macaca Mulatta, Occipital Lobe, Psychomotor Performance, Motor Neurons, Psychology and Cognitive Sciences, and Medical and Health Sciences
When people make a choice between multiple items, they usually evaluate each item one after the other repeatedly. The effect of the order and number of evaluating items on one's choices is essential to understanding the... more
When people make a choice between multiple items, they usually evaluate each item one after the other repeatedly. The effect of the order and number of evaluating items on one's choices is essential to understanding the decision-making process. Previous studies have shown that when people choose a favorable item from two items, they tend to choose the item that they evaluated last. This tendency has been observed regardless of sensory modalities. This study investigated the origin of this bias by using three experiments involving two-alternative forced-choice tasks using handkerchiefs. First, the bias appeared in a smoothness discrimination task, which indicates that the bias was not based on judgments of preference. Second, the handkerchief that was touched more often tended to be chosen more frequently in the preference task, but not in the smoothness discrimination task, indicating that a mere exposure effect enhanced the bias. Third, in the condition where the number of touc...
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In the drive towards miniaturization in manufacturing, accuracy in positioning minute objects by camera is vital. For visual servoing, the rapid and robust detections of features in camera images is also essential to production line... more
In the drive towards miniaturization in manufacturing, accuracy in positioning minute objects by camera is vital. For visual servoing, the rapid and robust detections of features in camera images is also essential to production line efficiency. Template matching provides flexibility in achieving this, often lacked by other methods, because it avoids the need to set object-specific parameters. Unfortunately, standard methods
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Prior research has demonstrated that during two-alternative decision making, gaze is biased towards the alternative that is eventually chosen. The Gaze Cascade model proposed by Shimojo, Simion, Shimojo, and Scheier (2003) predicts a... more
Prior research has demonstrated that during two-alternative decision making, gaze is biased towards the alternative that is eventually chosen. The Gaze Cascade model proposed by Shimojo, Simion, Shimojo, and Scheier (2003) predicts a larger bias for decisions requiring one to choose the item that is liked the most versus decisions that require one to choose the item that is disliked most. More recently, Park, Shimojo, and Shimojo (2010) showed that preference formation operates differently during decisions among faces and scenes, which suggests that gaze bias might differ depending on whether the decision stimuli are faces or scenes. In the present study we tested these two hypotheses in a within-subject design. Eye movements were monitored while participants (n = 48) made two-alternative Like or Dislike decisions among pairs of faces or scenes. We found remarkably little influence of stimulus type on gaze bias for either decision task, which disconfirms the hypothesis that gaze bias operates differently for faces than scenes. In contrast, we found that gaze bias was stronger for Like decisions than Dislike decisions. To further account for this effect we examined the decision time course, which revealed that this task effect is primarily related to biases in the placement, and duration, of the final dwell prior to response, although there was evidence that the bias began earlier for Like decisions. Implications for mechanisms of gaze allocation during multi-alternative decision making are discussed.
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Conventional force display systems provide a force sensation by applying force to the operator's body via actuators such as electric motors. These systems can potentially harm the operator, especially when providing a large force... more
Conventional force display systems provide a force sensation by applying force to the operator's body via actuators such as electric motors. These systems can potentially harm the operator, especially when providing a large force sensation. This study shows that constrictive pressure on the distal part of the forearms provides a force sensation such as holding a heavy object or pushing a wall when the pressure changes in accordance with the hand motion. This force display provides a large force sensation of ∼10 N without applying real force to the operator's hand, which makes the system intrinsically safe and suitable as a wearable force display system. Experimental results show that the discrimination thresholds are consistent with Weber's Law. It was demonstrated that an operator could sort virtual objects by weight using this system.
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A particle mechanical constraint (PMC) is a soft vinyl tube containing Styrofoam beads. It can be freely compressed, elongated, bent, twisted, or otherwise manipulated in all degrees of freedom. Evacuation of the air inside the tube makes... more
A particle mechanical constraint (PMC) is a soft vinyl tube containing Styrofoam beads. It can be freely compressed, elongated, bent, twisted, or otherwise manipulated in all degrees of freedom. Evacuation of the air inside the tube makes the PMC rigid so that it maintains whatever shape it has been given. The stiffness of the PMC is proportional to the reduction in internal pressure below atmospheric pressure. Viscosity is also controlled virtually by changing the inside air pressure in proportion to the speed of transformation of the PMC. We used a PMC to develop a wearable force display that provides the sensation of coming into contact with a wall or of moving in water with viscosity, in addition to that of moving in air. PMC is an inherently passive device that never exerts excessive force if it were to malfunction. In short, it is suitable as a wearable human interface because it is light, soft, and safe.
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Research Interests: Neuroscience, Psychology, Cognitive Science, Medicine, Space perception, and 15 moreBrain Mapping, Movement, Animals, Posterior Parietal Cortex, Motor Cortex, European, Premotor cortex, Parietal Lobe, Macaca Mulatta, Neural pathways, Inferior Parietal Lobule, Neurosciences, Frontal Lobe, Occipital Lobe, and intraparietal sulcus
Research Interests: Treatment, Self Care, Medicine, Humans, Hypertension, and 15 moreBlood Pressure, Female, Male, Clinical Sciences, Aged, Middle Aged, Theoretical Models, Morning, Amlodipine, Exponential Function, Oscillation, Calcium Channel Blockers, Blood Pressure Measurement, Arterial pressure, and Exponential Decay
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When people are presented with a pair of images and asked to identify which one is more attractive, their eye gaze shifts gradually toward the image that they eventually choose. This study examined whether this sampling bias also occurs... more
When people are presented with a pair of images and asked to identify which one is more attractive, their eye gaze shifts gradually toward the image that they eventually choose. This study examined whether this sampling bias also occurs in other sensory modalities by observing participants' behavior in a haptic preference task. The results indicated that the participants tended to sample the chosen item just prior to making their decision when they were instructed to identify their most preferred item (i.e., the "like" task), but not when they were instructed to identify their least preferred item (i.e., the "dislike" task). This indicates that the sampling bias is a general phenomenon regardless of sensory modality. In addition, the sampling bias in the like task was larger when the difference in preference ratings between the paired items was smaller. However, the sampling bias decreased when the two items were given equal preference ratings, despite there ...