Pouring work in casting comes with risks because it involves handling high-temperature molten metal. Automation is in demand; however, owing to the specialized nature of pouring work, flexible operation remains challenging. This study developed a teleoperation system for pouring work using a robotic arm. This developed interface for Cartesian coordinate manipulation, called iFeel Desktop Haptic Device (IFHD), was applied. Additionally, a force feedback model was developed based on the amount remaining in a ladle to provide the operator with force feedback and enhance operability. Experiments were performed using three operation methods: IFHD, IFHD with force feedback, and a tablet device (conventional method). The results revealed that the completion time when using IFHD decreased significantly (p = 0.0185) compared with the tablet, without a decrease in accuracy. Moreover, when using IFHD with force feedback, the operator’s brain activity decreased significantly compared with IFHD without force feedback (p = 0.0341). This suggests that the proposed force feedback contributes to the reduction of the operator’s stress during pouring operations.

In recent years, the number of traffic accidents caused by the errors of older adults while driving in Japan has been on the increase. As we age, changes in reaction time can make it more challenging to drive safely. We aim to develop a system that estimates the driver’s intention and assists the driver in driving accordingly. We investigated whether the detection of movement-related cortical potential, which is a component in electroencephalography (EEG) that occurs before driving, would enable us to detect a driver’s intention to steer. In this study, we conducted experiments to measure EEG signals while a participant drove on a simulator. We analyzed the results using machine learning and classified the EEG during straight driving and before and after steering. Because the optimal learning model for a classifier to detect Movement-Related Cortical Potential from EEG has not yet been derived, we trained Light GBM, LDA, SVM, and LSTM models and identified an appropriate classifier. The result reveals that the best accuracy was obtained with Light GBM, which was able to detect steering intentions with an accuracy of approximately 60%. Further improvements in estimation accuracy and the development of a driver assistance system based on steering intention are future tasks.

In tele-surgery, surgeons remotely operate a surgical robot via the leader-follower system. However, communication delays often lead to challenges that can affect the ease of operation. In this study, we evaluated the intuitive operability of surgical robotic systems by measuring brain activation in the intraparietal sulcus, which serves as an interface between visual information and body motor control. The participants completed a suturing task in virtual reality using a surgical simulator. We randomly introduced time delays while measuring brain activity using functional Near-Infrared Spectroscopy. We found significant differences in task completion time and activity in the right intraparietal sulcus according to the delay time. According to our data, delays of 300 ms or more could be identified as one of the indicators that negatively affect intuitive operability in tele-surgery.

A fall on stairs can be a dangerous accident. An important indicator of falling risk is the foot clearance, which is the height of the foot when ascending stairs or the distance of the foot from the step when descending. We developed an augmented reality system with a holographic lens using a visual illusion to improve the foot clearance on stairs. The system draws a vertical striped pattern on the stair riser as the participant ascends the stairs to create the illusion that the steps are higher than the actual steps, and draws a horizontal striped pattern on the stair tread as the participant descends the stairs to create the illusion of narrower stairs. We experimentally evaluated the accuracy of the system and fitted a model to determine the appropriate stripe thickness. Finally, participants ascended and descended stairs before, during, and after using the augmented reality system. The foot clearance significantly improved, not only while the participants used the system but also after they used the system compared with before.

Intuitive robotic tele-operation is a necessary but often difficult task for users because the structure of a robot is different from that of a human body. Our previously developed novel interface allows a user to operate a robot intuitively because the user manipulates this interface according to the Cartesian coordinate system. However, interference between the axes in the interface causes unintended input by the user and reduces operability. In this study, we develop a model that identifies whether each input is the user's intended or unintended input. We obtained the displacement and angle of the interface's grip in each direction and investigated the interference relationships between axes. As a result, the large interferences were in the pairs of pitch and Z-axis, and yaw and Y-axis. Finally, we constructed an identification model using a recurrent neural network. The models for all axes achieved F1 scores above 0.97.

This article assessed how surgical robot parameters influenced operator viewpoint during a simulated surgical procedure. Surgical robots are useful tools in minimally invasive surgery. However, even with robots, suturing is difficult because the needle is sometimes obscured by tissue or manipulators and is thus not always visible during the procedure. This is especially true in pediatric surgery, where the surgical environment is smaller than in adult surgery. Hence, surgeons must carefully track the instruments and tissues to understand and predict their current and expected situations. In this article, we used gaze-tracking techniques to analyze the location and timing of the gaze of participants while they manipulated a virtual robotic surgical simulation system. To differentiate between the ideal and actual viewpoint trajectories, we conducted experiments with and without obstacles (i.e., simulated tissue and the manipulator arm). In the obstacle condition, we modulated the wrist length of the manipulator to bring it into view. In the no-obstacle condition, the participants mostly watched the suture needle tip. In the with-obstacle condition, the participants spent less time watching the instruments and more time watching the target point. The amount of time spent watching the target point increased as wrist length increased. Given this tradeoff relationship, we examined the proportion of time the participants spent looking at the instruments or target points by wrist length. We calculated the Pareto solutions and clarified the relationship between wrist length and the watching parts.

This paper reports on a development of motion simulator for charge-induction electrostatic actuator. The simulator deals with planar 3-DOF motions, which are XY 2-DOF translations and rotation. To simplify the simulation process, the paper sets two assumptions on the electrostatic force generation within the actuator. One is that the induced charges on the slider will be kept fixed during a step motion of the slider. Second is regarding a skewed condition, where charge distribution on the slider is skewed against the stator electrodes. The paper assumed that, if we focus on a small element, the electrostatic force for the skewed condition can be calculated in the same manner as the normal condition. The simulated motion trajectories using those assumptions fairly matched with experimental observations. Also, how to simulate the friction between the stator and the slider is discussed using three simple friction models.

Movement/walking assistance devices have the great advantage of supporting quality of life for the elderly in an aging society. To strike a balance between efficiency of movement and employment of the elderly user's own body, we developed a smart mobility system called Tread-walk, which is controlled by the user walking on a treadmill and amplifies the user's walking speed. Since the user's walking speed is different from the speed at which the Tread-walk moves, users experience a mismatch between their visual optical flow and somatic sense. In this article, we validate the feasibility of an amplifying gain decision method that analyzes user brain activity. To control Tread-walk, the visual sense is integrated with somatosensation in the parietal area of the brain and controlled in the medial prefrontal cortex. Therefore, first, we measure the parietal area when the participants walk while looking at their virtual optical flow. Second, we measure the medical prefrontal cortex when the participants control Tread-walk 2. These experiments are carried out for a variety of speed amplifying gains. We find that the brain activates significantly at amplification gain K = 1.1-1.7 in the virtual optical flow experiment and K = 1.5-2.0 in the Tread-walk experiment; this brain activation represents the amplification gain at which the visual and somatosensory senses seem to receive similar input. In conclusion, the brain would activate the most significantly at the most appropriate amplification gain.

Being ubiquitously used as anti-adhesive and wound-covering mechanisms, thin films have potential therapeutic uses as cell sheets to target inner organs while navigating narrow environments. A significant challenge to realize versatile films lies in achieving compact storage and efficient transport while ensuring coherency in curvature-bounded environments. In this paper, we propose a folding mechanism of a curved film by using a spiral approach, enabling efficient unfolding and flexible plasters with curved surfaces. Our experiments using gelatin-based films with curved surfaces shows the superior indwelling ability in terms of chromaticity level compared to the conventional planar films, as well as the efficient unfolding in the order of seconds. Our results presents the theoretical and experimental building blocks to realize a versatile class of films which are able to navigate narrow environments, and unfold efficiently and flexibly.

The increase in care-receiver/caregiver ratio is becoming a social problem in Japan, one factor in which is the increase in the number of falls in the elderly. The purpose of this study is to develop a balance training ability system for fall prevention. To effectively improve balance ability while walking, dynamic training specialized for somatic sensation is useful. We developed a system that greatly improves balance ability by removing visual information of the outside world during gait training and by producing visual feedback of somatic sensation information, consisting of joint angle information about the whole body and foot pressure distribution information, that is, somatic sensation information used for gait. One technical problem with this system is the selection of display method at the time of visual feedback. Therefore, in this paper, we hypothesize that the training effect improves when a combination of foot pressure information and joint information is used. As specific presentation information, center of pressure (hereinafter called CoP) and ideal CoP traces derived from each joint angle were used. The ideal CoP trace is shown with a broken line connecting the heel, metatarsal and toe-tip part of the foot, and is updated every 10 walking cycles by changing the transverse coordinates of the metatarsal and toe-tip. To verify the abovementioned hypothesis, we created a machine equipped with the feedback system, and verified and tested it. To create the feedback system, the relationship between each joint angle in the body and ideal CoP traces were derived by a multiple regression analysis of the gait data (foot pressure distribution, joint angle) of young, physically unimpaired volunteers. In the verification experiment, we compared the training using the feedback system to that without in a visual sense cutoff state. The standard deviation a of right-and-left directions of the CoP traces was used as a performance index of balance ability. Increased a indicates reduced dynamic balance ability. We found that a increased by 0.61 times by feedback training, which was a significant decrease, and by 0.84 times after the visual sense interception training. A significant difference (p < 0.05) was seen between the effects of these two training types, suggesting that dynamic balance ability is improved by our feedback system. In future, we will verify the long-term training effects over several months or years, as well as the improvement in motivation over training.

Mechanical performance of a surgical robot can be evaluated and improved based on a working score; however, intuitive operability cannot be evaluated in this way. We propose a method that measures the user's brain activity for evaluating intuitive operability from the perspective of cognitive science. We hypothesized that hand-eye coordination, such as the slave configuration for the endoscope, has the greatest effect on intuitive operability, because it is the cause of physical differences between a human and a robot. The objective of this paper is to clarify the appropriate slave configuration for the endoscope to study hand-eye coordination using brain activity measurements. In the experiment, we used a brain imaging device, optical topography, to measure the users' brain activity while they controlled the hand-controller to position the tip of the virtual arm on the target. The experiment was carried out a number of times with the virtual arm position configured in a variety of ways. According to the results, some subjects showed peak performance with a specific slave configuration. We conclude that the slave configuration with the highest brain activity depends on the body image, which is a spatial symbol in the human brain from the perspective of cognitive science.

Tide gauge observations along the coastline of Japan have recorded the land sinking due to the continuous subduction of the oceanic plates, indicating that stress and strain energies have been accumulating at the plate boundary, which would eventually cause large oceanic trench earthquakes like the 2011 Great East Japan Earthquake. The proposed method extracts such long-term activities of the Earth's crust together with rapid displacements related to earthquakes, even before the establishment of the global positioning system, from monthly mean data of the sea levels. A state space model decomposes the tide gauge time series into trend, seasonal, autoregressive and observation noise components, each of which are estimated using the particle filter algorithm. The spatial and temporal distributions of the extracted trend component clearly indicate high-risk regions, near which giant earthquakes have occurred or are predicted to occur. A multivariate analysis of the observatories located at the northeast coast of Japan successfully determines the past crustal displacement in the case of the 1978 Off-Miyagi Earthquake. The proposed method has the potential application for monitoring crustal activities related to the accumulation of earthquake energy.

Surgical robots have undergone considerable improvement in recent years, but the intuitive operability, representing user inter-operability, has not been quantitatively evaluated. Thus, we propose a method for measuring brain activity to determine intuitive operability in order to design a robot with intuitive operability. The objective of this paper is to clarify the angle between the endoscope and the manipulator that facilitates users perceiving the manipulator as part of their body. In the experiments, while subjects controlled the hand controller to position the tip of the virtual slave manipulator on the target in the surgical simulator, we measured the brain activity through brain imaging devices. We carried out the experiment a number of times with the virtual slave manipulator configured in a variety of ways. The results show that activation of the brain is significant with the slave manipulator configured such that the angles are slanted with respect to the horizontal. We conclude that the body image affects hand-eye coordination, which is related to visual and somatic sense feedback.