Human–animal interaction in virtual reality has been explored for stress relief, yet balancing practical ease of use with natural haptic experience for relaxation remains a key challenge. We investigated whether mid-air ultrasound haptics, rendering breathing and fur stroking cues without wearable haptic devices, could enhance relaxation with a virtual cat. We first conducted a perceptual study to design a tactile cue for a cat’s breathing. By synchronizing expansion–contraction of the ultrasound focal region with intensity modulation, we demonstrated the realism and expressivity of the breathing cue. Next, we conducted an application study in which participants engaged in a short relaxation session with a virtual cat. Physiological and subjective measures showed that ultrasound haptics enhanced relaxation compared to both non-haptic interaction and controller-based vibrotactile feedback. These findings suggest that ultrasound haptics can extend VR-based human–animal interaction by combining accessibility with psychological benefits, opening new opportunities for well-being and therapeutic applications.

Third-person perspective (3PP) VR can afford dual embodiment, letting users act through an in-world avatar while simultaneously operating an omniscient entity (OE) from a detached viewpoint. We investigate how the sense of body ownership (SoBO) reallocates between these two asymmetric entities during continuous play. We systematically varied macro-level design factors—avatar and OE involvement—across three maze scenes and one combat scene in a within-subjects study. After each trial, participants produced time-aligned, continuous SoBO traces for both entities; gaze and controller signals were logged, and recall interviews captured first-person explanations. This research reveals three main findings. First, SoBO is not statically fixed but dynamically reallocated between the avatar and the OE across task phases. Second, allocation follows design factors: higher OE involvement in the maze strengthened ownership toward it, while combat consistently favored the avatar. Third, moment-to-moment gaze and control intensity predict ownership allocation, with fluency and salient events emerging as additional influences. These findings provide a framework for understanding dynamic SoBO and inform the design of adaptive 3PP VR systems.

A prevailing assumption in Virtual Reality is that the perception of surface gloss attenuates with viewing distance due to the resolution limitations of head-mounted displays (HMDs). While prior work indicates that resolution loss can degrade cues such as highlight sharpness and binocular highlight consistency, the direct linkage between viewing distance and perceived gloss has not been systematically established in VR. This study systematically investigates this relationship, focusing on binocular highlight intensity asymmetry. Contrary to the common assumption, under physically based rendering, our results show no reliable decrease in perceived gloss with distance within the tested range, despite resolution limitations. Moreover, participants' gloss judgments appeared to be more strongly modulated by monocular cues (e.g., highlight luminance, contrast, and temporal information) than by the binocular asymmetry manipulation tested here under our tested conditions. Finally, we find that moderate departures from physically correct binocular highlight consistency did not, within a tested tolerance, undermine perceived realism. These findings provide a new basis for designing efficient rendering techniques that preserve gloss fidelity over distance in VR, suggesting that computational resources might be better allocated to preserving monocular cues.

Humans sometimes encounter dazzling light in everyday life, such as sunlight or high-beam headlights, which often evoke instinctive biological responses like blinking and afterimages. Accurately reproducing such phenomena is essential for enhancing realism in virtual reality (VR), especially in scenarios like training simulations or entertainment experiences. While conventional methods either rely on high-luminance displays or simulate isolated perceptual effects such as glare, few approaches have explored the combination of multiple physiological responses to intensify brightness perception without using physically intense light sources. This study addresses the gap by investigating how pseudo-blinking and afterimage presentation, in addition to glare effects, can enhance the dazzling sensation in VR. We developed a novel system that synchronizes screen darkening with skin-deformation-like vibration stimuli around the eyes to simulate a blink reflex, followed by gaze-dependent afterimage presentation that dynamically transitions to complementary colors in response to user blinking. Experimental results with 19 participants revealed that both pseudo-blinking and afterimage effects significantly enhanced the perceived dazzling sensation and realism. These findings suggest that simulating involuntary physiological reactions to light in VR can evoke strong perceptual impressions, enabling safe and cost-effective glare expression.

Impact sensation is vital for achieving high realism and immersion in virtual reality (VR) applications such as sports games. There has been substantial research focusing on the moment of impact, using methods like electrical muscle stimulation (EMS) and vibrotactile feedback. However, the size and complexity of these devices, along with concerns for user safety, limit their effectiveness in producing strong impact sensations. Additionally, less attention has been given to sensations experienced after a strong impact, like the tingling that follows a collision. This research focuses on an overlooked area: the aftereffects that emerge within the body following a physical impact. It specifically examines the tingling sensation that occurs after a strong hit, using a VR baseball bat-like device designed to deliver impulsive force, vibrotactile, and thermal feedback to the user’s hand. We conducted a user study (18 male, 6 female participants) to assess how these types of feedback affect the realism and intensity of impact sensations, as well as the tingling sensation perceived by users. The results revealed that both vibrotactile and thermal feedback as aftereffects significantly enhanced the impact sensation, confirming their ability to induce tingling sensations. Additionally, high-frequency vibrotactile stimuli particularly enhanced the tingling sensation and realism of impact. Although the sample had a gender imbalance, these findings highlight the potential for incorporating aftereffects feedback in VR systems to enhance impact sensations for entertainment and safety education purposes.

Paranormal visual effects, such as spirits and miracles, are frequently depicted in visual games and media design. However, current methods do not express paranormal experiences as aspects of the sixth sense. We propose utilizing binocular rivalry to provide a new visual presentation method by displaying different images in each eye. In this study, we conducted two experiments. Experiment 1 assessed paranormal sensation, color perception controllability, and visual discomfort caused by mismatched colors in each eye in relation to color difference. Experiment 2 assessed our proposed visual presentation method in three application scenarios. The results indicate that our proposed method improves the visual experience of more realistic paranormal phenomena. Moreover, the sensation of paranormal activity, color perception controllability, and visual discomfort increase as the color difference between the colors displayed in the two eyes increases.

This investigation proposes a novel method to enhance the perceived temperature of food, aimed at helping individuals with conditions like dentin hypersensitivity who struggle to consume foods at optimal temperatures. Conventional methods for this purpose often are impractical for sensitive individuals. This study introduces a new technique that applies external cold stimuli to the posterior neck, avoiding direct contact with oral sensory receptors. We designed a device to deliver precise cold stimuli to this area and empirical assessments were conducted using ice cream, selected for its cooling properties and variable texture. The focus was on synchronizing the cold stimuli with the swallowing process, hypothesizing that this coordination could enhance thermal and tactile perception integration without disrupting eating. The study engaged 25 participants and utilized Ura’s modification of Scheffé’s paired comparison method for statistical evaluation. The results show that this technique significantly enhances the sensation of cold in food, suggesting that external thermal stimuli can improve the dining experience without altering the food itself or affecting the taste.

This work-in-progress research paper aims to elucidate the appropriate form of teacher images in online learning content and establish the knowledge necessary to construct content with learning effects. Our previous research found that it is adequate to maintain and improve the level of understanding when the presence or absence of the teacher's image matches the learners' preferences. Therefore, our research question was whether a similar trend could be observed among the younger generation as elementary school students. Furthermore, we hypothesized that students would be more likely to prefer content that presented an image of a teacher and that they would spend a lot of time fixating on the teacher's image. We experimented to verify this hypothesis. In this paper, we conducted quizzes for 21 elementary school students (4th to 6th grade) that simulated on-demand learning. Then, we calculated the correct answer rates for the quizzes and measured the eye gaze points during the quizzes. The quizzes consisted of five multiple-choice questions that included common sense and riddles. In addition, two types of content were created and used: one that included the teacher's face image and one that did not. We got the result when the presence or absence of a teacher image in the video content matched the participant's individual preferences, and learning effects improved until four weeks after the experiment. Additionally, the participants whose correct answer rates improved from the first quizzes gazed longer time rate at the options area during the explanation sections. According to the results, we consider it essential for students to solve the questions themselves again while watching the explanation's contents with the teacher's image matched their preferences to enhance comprehension of the teacher's explanations.

In virtual environments, wind displays can reproduce the sensation of wind to enhance user experience such as presence. Enabling users to perceive strong winds can benefit several applications, such as disaster education and entertainment content. However, the large and bulky equipment required to blow strong winds across the entire body of the user limit its application. Although cross-modal effects are proposed to alter wind perceptions through multisensory stimuli, but methods to induce the perception of strong winds without generating a strong wind need further exploration. In this study, we propose a method to create an illusion of strong wind by providing tactile stimuli through clothes. We developed a compact and lightweight wearable device that vibrates the fabric by a motor to simulate its fluttering motion under a strong wi nd. Two user studies were conducted to investigate the effect of vibrating the clothes on the perceived wind velocity, realness of the wind, and presence. The results indicated that tactile stimuli provided by vibrating the clothes increased the perceived wind velocity to a similar level as the strong wind exceeding $10 \mathrm{~m} / \mathrm{s}$ while the parameters of the physical wind were unchanged. It was also revealed that the vibration of the clothes decreases the realness of the actual wind and a visual scene of the clothes of the avatar flutter increases presence. Thus, the proposed wearable device is useful for creating the experience of strong winds while keeping the wind displays compact.

Remote robot teleoperation is crucial for tasks that require human oversight, yet latency can significantly impair operator performance and result in discomfort, break inpresence and increased workload. In this paper, we propose a new robot teleoperation technique based on Virtual Reality that is expected to alleviate the negative impactson subjective experience caused by latency. The technique allows users to manipulate a virtual robot synchronized with a real one by ‘grabbing’ a virtual spring attached to it. Controller vibration is also used to simulate spring force feedback, together creating an illusion that the position discrepancy is caused by the dynamics of the spring instead of latency. We hypothesize that this approach can mitigate the negative effects of latency by making the robot’s movement appear less strange and more natural. A user study was conducted to evaluate the effectiveness of virtual spring and controller vibration separately using a $2 \times 2$ factorial design. The results suggest that the virtual spring enhanced user comfort level and the sense of presence, but the controller vibration showed no clear benefits.

In this paper, we show the results of examining the possibility of emotion analysis based on students' voice analysis. Some research focus on the students' facial expressions to understanding their states in online classes. However, applying the conventional emotion estimation model with facial expressions may be difficult in some cases because facial expressions during class are not clarified and defined. Therefore, we focused on students' voice, which they generally use for communication in online classes. We analyzed the spoken voices of 50 junior high school students using commercially available speech emotion analysis software (InTone, Nemesysco Ltd.) that outputs 14 emotional and five conversation states from the utterance voices. We tasked the junior high school students who participated in the experiment with answering five multiple-choice quizzes orally, as same as they answer questions asked by a teacher in a general class. We found those four emotions correlate with the answer correctness: anticipation$(\boldsymbol{p} < \mathbf{0.001}, \boldsymbol{r} =\mathbf{0.5})$, excitement$(\boldsymbol{p}=\mathbf{0.003}, \boldsymbol{r}=\mathbf{0.4})$, hesitation$(\boldsymbol{p}=\mathbf{0.030}, \boldsymbol{r}= \mathbf{0.3})$, and upset$(\boldsymbol{p}=\mathbf{0.046}, \boldsymbol{r}=\mathbf{0.3})$. According to the results, we confirmed the possibility of recognizing students' emotions related to their confidence from students' answer voices in class.

This study systematically reviewed 38 research papers on microteaching practices using online technology. It was found that online microteaching utilizes technology in both synchronous and asynchronous settings. Mixed methods research was most popular for examining online microteaching's effectiveness. Online microteaching is the same as or superior to the face-to-face environment in terms of competence development, self-efficacy and motivation, flexibility and convenience, evaluation and feedback, and engagement and enjoyment. Disadvantages of online microteaching are technical issues, limitations of the online environment, and collaborative role engagement aspects. This paper encompasses future directions for effectively using online microteaching in post-COVID-19 teacher education.

The development of methods to simulate the sensation of wind that can promote relaxation and elicit positive emotional responses has become a topic of interest with the widespread adoption of virtual and augmented reality systems. Previous studies have simulated natural wind by varying wind speed in a controlled environment or moving a large flow of air through an area. In contrast to such approaches to modulate physical airflow, the use of multisensory stimuli to alter the impression and sense of comfort provided by a simulated wind has rarely been considered in previous research. If visual and auditory stimuli affect wind comfort, a multisensory design should be considered for relaxation systems that use wind effects. Therefore, we experimentally measured wind comfort and associated emotions when participants experienced outdoor and indoor virtual environments through immersive virtual reality to investigate whether cross-modal effects of variations in audio-visual stimuli would impact the relaxation effects associated with a virtual wind. The results show that the virtual environment of an outdoor meadow and the sound of natural wind significantly improved users' subjective experience of comfort and openness associated with the wind, as well as their emotional state. Simulated natural wind reduced mental stress compared to a condition without wind, as shown by questionnaires and biometric data. The results of this study indicate that multisensory stimuli conveying natural impressions and simulated natural wind are effective for wind-based relaxation.

Although remote work has become common recently, the decrease in productivity has become a problem. Focusing on the impact of the presence of co-workers on productivity, we hypothesized that sharing work status among coworkers could improve productivity and reduce the discomfort of having work status monitored. First, more than 400 participants were surveyed to evaluate the effects of sharing work state on productivity and discomfort and to determine the factors that contribute to productivity. Based on the results, we designed a user study to examine work productivity and discomfort in non-shared, shared, and monitored work states. The results indicated that the actual work–time ratio was increased in the case of sharing work state. Furthermore, we suggested that being monitored state increases discomfort and motivation and that sharing work state reduces discomfort compared with the monitored state. These results indicated that sharing work status during remote work can improve motivation and work productivity.

The existing manufacturing systems based on processes involving the transportation of workpiece are unsuitable for large products such as air mobility systems. This study proposes a novel ultra-complex manufacturing system called the “Modularized-Structure and Multiple-Points Simultaneous Machining System (MS-cubic)” based on the concept of intelligent space, which simultaneously performs multiple types of machining processes without moving a workpiece. The system can simultaneously process multiple points and flexibly change its workspace by modularizing its structure. This paper presents a discussion on the requirements and constraints to generate a feasible design of the rail module and the machining unit, which are two main elements of MS-cubic. The performance of the prototype MS-cubic is evaluated, and its stiffness is observed to be sufficient to perform drilling. Furthermore, the modularized design of system enables the fluid and electric power supply for the machining process.

Odor display has been a popular approach in virtual reality (VR) to enhance users’ multi-sensory experience. The existing multi-odor presentation methods in VR are mostly based on spatiality of scent sources to produce mixed scents, which will possibly compromise users’ olfactory experience because humans normally have poor ability to analyze distinct odorant components from a mixture. To tackle this problem, we present a VR multi-odor display approach that dynamically changes the intensity combinations of different scent sources in the virtual environment according to the user’s attention, hence simulating a virtual cocktail party effect of smell. We acquire the user’s gaze information as attention from the eye-tracking sensors embedded in the head mounted display (HMD), and increase the display intensity of the scent that the user is focusing on to simulate the cocktail party effect of smell, enabling the user to distinguish their desired scent source. We conducted a user study to validate the perception and experience of 2 ways of intensity settings in response to the user’s attention shift, which were a strong level of focused scent mixed with weak levels of non-focused scents and strong focused scent only. The results showed that both of the two intensity settings were able to improve olfactory experience in VR compared to the non-dynamic odor display method. Meanwhile, only the method of presenting strengthened focused scent while maintaining the weaker mixture of background scents showed significant improvement on simulating the olfactory cocktail party effect by giving the users an enhanced sense of their own olfactory sensitivity.

Unmanned robots have been proposed for the decommissioning of Fukushima Dai-ichi Nuclear Power Plant. To achieve efficient movement of robots in the high-radiation environment, we propose an “automated construction system of a modularized rail structure.” In the high-radiation environment, the rail structure must be constructed by a remotely controlled robot using minimal sensors. In addition, a compliant mechanism that allows small misalignments is not feasible in the module connection task due to multiple load conditions. Therefore, this study aims to achieve stable, sensor-less, and compliance-less construction using a remotely controlled robot. To achieve this goal, a geometrical model of a connection mechanism is generated and used for contact analysis of the kinematic chain transition. An analysis of the relative angle and distance between the connection surfaces of the modules effectively illustrates the conditions of connection success and failure. Based on the analysis results, the design is modified to stabilize the connection task and employed to update the constructor robot. Thus, the stability of the module connection is improved, even under various load conditions.

Ceiling mobile robots are anticipated for trans-porting component parts in production sites. In our previous study, we had developed a crawler-type ceiling mobile robot named "HanGrawler." In this study, we aim to realize 1 m/s and 90°/s speed movement on par with existing ground carriers, and reveal the factors contributing to the improvement in speed and stabilization. Accordingly, we develop HanGrawler 2, which inherits the basic approach of HanGrawler. In HanGrawler 2, the mechanism for hanging from the ceiling moves faster, and the driving power of the linear and rotational movements is improved drastically. Newly installed sensors detect the hanging mechanism and robot body position relative to the ceiling plate. By calculating the insertion timing based on the position of the hanging mechanism, the certainty of insertion is improved. Support rollers pressed against the ceiling stabilize the traveling posture of HanGrawler 2. Performance evaluation experiments confirm that HanGrawler 2 can travel linearly at a speed of 1 m/s with a 40 kg load and turn at a rotational speed of 90°/s. Based on the experimental results, it is confirmed that the design solutions for HanGrawler 2 are effective in realizing reliable ceiling mobility and that the high-responsiveness inherited from the original HanGrawler mechanism contributes to the realization of high-speed movement.

In recent years, technologies related to virtual reality (VR) have continued to advance. As a method to enhance the VR experience, we focused on loud vocalization. This is because we believe that loud vocalization can enable us to engage with the VR environment in a more interactive way. Also, as loud vocalization is an action that is thought to be closely related to stress reduction and a sense of exhilaration, the stress reduction through VR with loud vocalization is also expected. But loud vocalization itself has disadvantages for physical, mental, and social reasons. Then, we hypothesized that loud vocalization itself is not necessary for such benefits; but the sense of loud vocalization plays an important role. Therefore, we focused on a method of substituting experience by presenting sensory stimuli. In this paper, we proposed a way to present the sense of loud vocalization through vibratory stimuli to the larynx and auditory stimuli to users who are actually vocalizing quietly with the expectation for the sense of loud vocalization. Our user study showed that the proposed method can extend the sense of vocalization and realize pseudo-loud vocalization. In addition, it was also shown that the proposed method can cause a sense of exhilaration. By contrast, excessively strong vibratory stimuli spoil the sense of loud vocalization, and thus the intensity of the vibration should be appropriately determined.

In this article, we present a ceiling-mounted mobile robot, HanGrawler, with high-speed mobility and the ability to freely select and adjust its route under a ceiling plate. HanGrawler hangs from the holes of a perforated metal ceiling plate using newly developed mechanically constrained hanging mechanisms mounted on crawler-type traveling equipment. These mechanisms continuously grasp the ceiling holes while moving in a straight line. Specially designed turntables are installed at certain ceiling points to change the HanGrawler movement direction to facilitate two-dimensional motion. A performance evaluation experiment confirms that HanGrawler can travel linearly at 0.1 m/s, turn at an 8.5°/s rotational speed, and carry a maximum load of 60 kg. The experiment also reveals that HanGrawler can carry a heavy load only when the timings of the hanging mechanism hooking motions and turntable rotational speed are tuned. This transport system can be utilized not only for part transportation on production lines but also for logistics in general.

While working, people often perform purposeless actions, such as spinning pens and swinging their feet. The pleasant and addictive tactile feedback generated by those actions seems to trigger them. This is based on a principle called "operant conditioning." "Operant conditioning" is a phenomenon of change in people's behavior because of a reward obtained from the purposeless action. In previous studies, operant conditioning for the behaviors of animals such as mice have been discussed, but conditioning for the behaviors of humans has had little investigation. Therefore, we designed a feedback for people's action as a reward of conditioning, especially tactile stimulation, and verified whether the stimuli can induce a simple action. We selected "tactile apparent motion" as the reward because it can provide comfort by stimulating a mechanoreceptor called C tactile afferent. We designed a wearable device that can generate tactile apparent motion from a simple input action, such as tapping the heel. Using this device, we conducted user studies. The results showed that fast tactile apparent motion is effective in inducing simple actions repeatedly. Moreover, simple actions can be induced by tactile apparent motion even in the long term.

In modern society, chronic stress in the workplace is a serious problem because it causes numerous diseases. To prevent chronic stress, it is necessary to continuously measurement this type of stress in the workplace. Thus, it is necessary to realize a chronic stress estimation method with small load to users. Therefore, we proposed a method to estimate chronic stress level by measuring changes of body motion patterns during desk work caused by chronic stress. For the acquisition of body motion patterns we called "Motion Pattern", a cushion-type sensor device with six pressure sensors was developed, and the changes of seat pressure distribution during desk work were measured. "Motion Pattern" was the time-series pattern of four"Motion Labels" including "Impact Label" which represented the motion that impacts the seat. We tried to estimate chronic stress level by learning the relationship between this "Motion Pattern" and the score of stress evaluation questionnaire. As a result, it was found that there was a significant difference in the interval time of "Impact Label" occurrence in all six participants. In addition, we achieved to estimate the existence and non-existence of chronic stress with an average accuracy of 87.0% using a classifier learned for each individual and achieved to estimate chronic stress level with a maximum accuracy of 70.0%for one participant. It suggests that our proposed method has potential for chronic stress monitoring in the workplace.

Crop grow measurement technologies are important to increase the farm productivity. Detection and measurement of fruit volume are useful for forecasting and harvesting applications. Some environmental challenges such as lighting conditions or occlusions make the fruit detection difficult. Our approach is based on features extraction from images through a sub-image clustering technique. Then images being described as a number of pixel in various labels are used in a regression model to estimate the fruit volume. The validity of the proposed method in experimental condition is successfully verified. The method is evaluated also in a field condition but results were inferior to the expectation. This paper tries to elucidate the reasons of the insufficient performance and tries to improve the proposed method in terms of illumination condition, precision and calculation time.

In the present paper, we describe a method for constructing a remote ultrasound diagnostic system. Remote diagnosis can be realized using a communication network. We have developed a master-slave type remote medical system to diagnose shoulder diseases, such as dialysis-related amyloid arthropathy (DRAA), by ultrasonographic images. Proper positioning, orientation, and contact force between the ultrasound probe and the affected area of the patient are required in order to acquire proper diagnostic images. Safety and manipulability are also required when operating the remote medical system through a communication network. Therefore, the system has impedance control capability for positioning of the master and slave manipulators in order to convey the contact force and enhance manipulability. In addition, the system has continuous-path control capability for the orientation of the slave manipulator in order to realize smooth and accurate motion of the ultrasound probe, even if the sampling rate of the transmission of the orientation data of the master manipulator is not sufficient. The results of remote diagnostic experiments demonstrated that a healthcare professional could diagnose real patients through a communication network using the constructed system.

Remote surgery is one of the most desired applications in the context of recent advanced medical technologies. For a future expansion of remote surgery, it is important to use conventional network infrastructures such as Internet. However, using such conventional network infrastructures, we are confronting time-delay problems of data transmission. In this paper, a remote surgery experiment between Japan and Thailand using a research and development Internet is presented. In the experiment, the image and audio information was transmitted by a newly developed low latency CODEC system to shorten the time-delay. By introducing the low latency CODEC system, the time-delay was shortened compared with the past remote surgery experiments despite the longer distance. We also conducted several network measurements such as a comparison between TCP/IP and UDP/IP about the control signal transmission.

Several robotic surgical systems have been developed for MIS (minimally invasive surgery) including commercialized products such as da Vinci and ZEUS. We have developed a minimally invasive surgical system, which have carried out remote surgery experiments for five times at the writing time. In this paper, a remote surgery experiment, which was conducted between Japan and Korea by using the developed minimally invasive surgical system is described. Research & Development (R & D) Internet testbet, APII (Asia-Pacific Information Infrastructure), which consists of an optical submarine cable network KJCN (Korea-Japan Cable Network), was used. In the experiment, a laparoscopic cholecystectomy was successfully carried out on a pig. The network time-delays of control signal and images were 6.5 msec and 435.5 msec respectively. A comparison of remote surgery experiments using ISDN and the Internet was studied

Fracture reduction of carpal bones is rather difficult, because of their tight formation. Therefore, it is difficult to recognize their posture and position as well as their segmentation. This paper deals with a novel robotic system for a K-wire guiding using CT and fluoroscopic images for scaphoid fracture reduction. The robot is designed to consider issues such as sterilization, X-ray halation and easy setup. Template matching in registration is investigated focusing on shape and structure of the carpal bones as well as scaphoid itself. Experiments show validity of the developed system in terms of insertion accuracy and operation time

We have been studying the technologizing of skill of the medical doctor in the medical diagnosis such as dialysis related amyloid arthropathy (DRAA) by ultrasonographic images. Proper position, orientation, and contact force between the ultrasound probe and the affected part of the patient are required to acquire the proper diagnostic image. In this paper, we propose a navigation system to support the medical doctor to realize proper position of the ultrasound probe by utilizing the constructed shoulder model based on the knowledge of the medical doctor and the analysis of the diagnosis

In this paper, a method of force feedback augmentation to improve the force perception is proposed. Reaction force is amplified naturally according to the forceps action. In particular, the principal force components corresponding to the ideal reaction force directions of the current forceps action will be amplified. The other components are displayed without amplification. As a result, only the simple but significant reaction force patterns are emphasized. Complex behavior of the reaction force, which may distract or deteriorate the intended action, is attenuated. In addition, the PI gain scheduling local force feedback controller compensates for the inertial and gravitational force of the master manipulator. Thus the true reaction force at the forceps can be felt more realistic

Several robotic surgical systems have been developed for minimally-invasive surgery including commercialized products such as da Vinci and ZEUS. We have developed a minimally-invasive surgical system, which had performed remote surgery experiments for four times until now (performed on pigs over 150 km in Japan). In this paper, two approaches that extend the system from the perspective of extensions of surgeon's dexterity are described. The first approach is a development of complex robotic forceps, which have multiple d.o.f. on their tip. A complex rigid link mechanism has been applied to the robotic forceps to realize 3 d.o.f. motions in a patient's abdominal cavity. With the rigid link mechanism, surgeons have no longer need to be concerned a cable cutting problem, which often can be happened on conventional cable driven systems. The second approach is a force feedback capability. The developed rigid link mechanism is preferable for an implementation of a force feedback capability. The force feedback capability is important not only for extending surgeon's dexterity but also for preventing unexpected damage on internal organs. An evaluation experiment of the force feedback capability on a simulated surgical procedure was conducted. An augmented force presentation method was developed that displays contact information between forceps and soft tissues. In an evaluation experiment, the load applied to soft organ tissues was reduced by approximately 30% compared with a conventional force feedback method.

This paper describes a novel robot system for fracture reduction of a femur with a reduction path navigation system based on 3D CT image modeling. The robot has 6-degrees-of-freedom to realize fracture reduction motion with a mechanical failsafe mechanism as well as a software failsafe. Furthermore, one 6-axis force sensor is installed to realize power assist capability for a doctor as well as to measure the force applying on the patient's femur. Three of the operation modes necessary for fracture reduction operation are introduced, i.e., a JOG operation mode, a power assist mode and an automatic operation mode. The control method of the power assist mode by means of one force sensor is proposed and explained in detail. Furthermore, the control method of the automatic operation mode is described to correspond with a real-time reduction path modification by the navigation system. Experiments are conducted to verify the failsafe function and accuracy of the motion control.

In total knee joint replacement, the femur and the tibia must be precisely shaped to ensure that they firmly mate with the artificial joint. The normal procedure is to manually cut the bones using a bone saw and mechanical jigs. A 9-axis bone cutting machine tool has been developed by the authors to increase cutting accuracy and reduce the hospital stay required for recuperation. As developed, the cut plane is determined by a 5 degree-of-freedom mechanism and the femur and tibia are cut by moving two translational and one rotational degrees of freedom, a system that provides a cutter path which avoids cutting the ligament. A preoperative planning system based on CAD/CAM principles and an overview of a system for total knee arthroplasty is also discussed. Experimental results showed the effectiveness of the developed robot and the system.

A master-slave type remote ultrasound diagnostic system was developed. This paper presents and evaluates its control strategy. There is only one impedance controller that is located in the master site or the slave site or the relay point in the conventional impedance controller. Therefore, the effect of the time lag in transmitting force and position data becomes large in the conventional system. Then we propose an impedance controller to cope with this problem. In the proposed system, the position controller for the slave manipulator is also constructed by means of a velocity-control-based impedance controller. This feature makes it possible to shorten the dead time taken by the slave manipulator to respond for the contact force input. This paper also reports the result of a clinical use of the remote ultrasound diagnostic system. The result of the experiments demonstrates that a medical doctor can diagnose patients as well as the conventional diagnosis.

This paper describes a tele-endoscopic surgical system with force feedback capability. The system consists of multi-media cockpit, surgical site and communication link. The multimedia cockpit is equipped with force feedback type master manipulators, visual and auditory information presentation apparatuses, and foot switches. A slave manipulator with 3 arms is located at the surgical site; the left and right arms hold forceps or a radio knife and the center arm holds an endoscope. The slave manipulator has a special safety mechanism. Vital signs can be also transmitted to the cockpit. In the experiment, a cholecystectomy was successfully performed on a pig at the distance of 150 km.

A master-slave type remote ultrasound diagnostic system was developed. The controller has impedance control capability for the master and slave manipulators' positions and has a continuous path (CP) control capability for the slave manipulator's orientation. The paper presents the controller of the slave manipulator's orientation. The remote ultrasound diagnostic system is one of remote medical systems through a communication network. Therefore it is difficult to transfer information for control at high sampling rate. To cope with this problem, we introduce a CP controller to this remote medical system. CP control realizes a smooth and less vibrated motion of the slave manipulator even if it is available to use a lower sampling rate of transmitting orientation data of the master manipulator. As a result, it allows the slave manipulator to improve safety and to decrease the volume of transmitting data. The experimental results demonstrate the accuracy of the path control of the slave manipulator during CP control in the master-slave manipulation system. The experimental results also show that a medical doctor can perform diagnosis properly using the developed system.

A master-slave type remote ultrasound diagnostic system was developed. This paper presents its controller. The controller has impedance control capability for the master and slave manipulators' positions. And it has also continuous path (CP) control capability for the slave manipulator's orientation. The impedance control allows the master and slave manipulators to move according to the motion control law, and allows the medical doctor to feel feedback force. Manipulability changes according to the impedance parameters. This paper makes clear the relationship of impedance parameters with manipulability and response speed, and proposes a method to determine appropriate impedance parameters. Experimental results demonstrate that the medical doctor can perform diagnosis successfully using the proposed system.

This paper discusses a robotic surgical system for total knee joint replacement. The system construction from preoperative assist system to bone-cutting robot is proposed. According to the examined system overview, a development of the bone-cutting system is presented as a main issue of this paper. The characteristic feature of the bone-cutting robot is to establish high rigidity, high cutting accuracy, high operability and high safety. These performances can be achieved by well-designed hardware mechanisms and degree-of-freedom configuration of the robot. In the last part, model bone cutting experiments prove the validity of the system compared with the conventional method using a bone saw. To be specific, the waviness of the machined surface and the error of the edge angle which affect fitness to the artificial knee have been improved dramatically.

This paper presents a master-slave type remote ultrasound diagnostic system. In the system, the motion of the master manipulator is controlled by a medical doctor and is reproduced by a slave manipulator carrying an ultrasound probe. The contact force between the probe and a patient is fed back to the master manipulator. High rigidity was achieved by adopting radius-guides in the slave manipulator. These allow precise position and orientation control of the ultrasound probe. In the master manipulator, a special mechanism keeps the orientation of the force sensor constant. The mechanism separates the functions determining the orientation and position of the probe. The control algorithm implements impedance control to reflect force, with the viscosity of the system varied depending on the measured force at the slave manipulator. Furthermore, a control strategy to enhance the safety of the system is proposed. Using the developed system, remote ultrasound diagnosis experiments through ISDN lines were successfully executed.

The authors describe a manufacturing system that allows the natural manipulation of tools of production and raw materials in environments which cannot be accessed directly by normal human senses. The term 'hyper-environment' connotes such an environment as remote locations, the micrometer world, or outer space. The authors discuss the functions necessary to realize the system, the software and hardware employed in the system, and the 'reality communication' techniques needed to allow the remote human operator to monitor the operation effectively. Attention is given to a technique for transforming cutting force information into auditory information that allows the operator to determine the cutting conditions. Tests in which a machining center in Tokyo was controlled by teleoperators in Washington are described.>