Almost all of conventional exploratory robots adopt crawler or wheel mechanisms. However, such robots are often stuck at narrow spaces. This study proposes an innovative flexible mobile robot named "MOLOOP". This robot consists of a hermetically-sealed outer cover with double-looped structure. The robot is driven by original flexible crawlers which are composed of multiple flexible bags with loop connection. Since the whole body of the robot is quite flexible, the body can change its shape adaptively according to the terrain. However, the performances of the previous prototype are not enough in terms of the speed and the size. This report describes the performance improvement of MOLOOP aiming speed-up and miniaturization. For the purpose of using high input pressure, this study reinforces the flexible bags of the crawler by fibrous materials. This improvement contributes not only the power of the crawler but also downsizing. The new HS crawler improves the torque and speed from 0.23 Nm to 3.43 Nm and from 3.0 mm/s to 39.0 mm/s respectively. The new prototype of MOLOOP with the new crawler achieves downsizing from 370 mm to 275 mm in the width. The speed is also increased from 3.0 mm/s to 9.0 mm/s. The prototype robot successfully passed through a space with 230 mm height which is narrower than the robot width (275 mm). For the purpose of shock resistance test, we dropped the robot from 1.5 m height to a hard floor. After that, it moved without any problems.

The assessment of jaw movements is a common method of evaluating stomatognathic function. However, with conventional methods, detailed examination of the interrelationship between maxillofacial morphology, tooth morphology, and jaw movements is difficult. Therefore, we engineered a method of analyzing individual three-dimensional （3D） jaw movements along a time axis. This study included five adult patients with permanent dentition and no notable oral parafunctional habits who visited the orthodontic department of the Showa University Dental Hospital. We used a jaw movement analysis system to assess jaw movements during free mastication. We assessed the （1） movement trajectory of the main occluding area, （2） rate of change in the distance between the origin and the insertion of the masticatory muscles, and （3） contact patterns of the dentition. The results for （1） showed no interrelationships. For （2）, the origin and insertion of the lateral pterygoid muscle exhibited characteristic changes. The analysis of the contact pattern between the upper and lower dentition showed the contact of the molars posterior to the first premolar when masticating on the balancing side. These results indicate that jaw movements occur in a way that is appropriate for the maxillofacial morphology when food is crushed during mastication. Additionally, the occlusal contact and condylar movement during mastication may be more affected on the balancing side than on the working side. Thus, the jaw movement analysis system used in this study was useful for movement analysis during functional activity.

This study proposes a flexible power-assist suit using a hydrostatic skeleton driving mechanism. For the purpose of a flexible, safe and slip-on system, the power-assist suit consists of a commercially available working cloth and a flexible actuator system. With this system, a dedicated handy controller is newly manufactured, and the power units such as compressor and battery are installed within a backpack to realize a portable system. The suit supports the motions of upper arm lifting, the elbow expansion and contraction. This paper describes a prototype suit system and its experiment. The total weight of the system realizes extremely light weight, approximately 3 kg. Moreover, the suit has achieved all the proposed motion.

It is difficult to control corrective forces in orthodontic treatment with clear aligners. The grip of aligners on teeth is important to ensure accurate corrective forces from aligners. This study aimed to measure the gripping force of aligners under various conditions to clarify factors that influence it. We created aligners with different attachment morphologies and placement sites and different margin lengths. We developed a device to measure the mechanics involved in the removal of these aligners. The gripping force was evaluated at five different aligner removal sites on the teeth. We found that the gripping force of the aligner was the weakest on the lingual side of the first molar and strongest on the labial side of the central incisors and that the attachment morphology and placement sites affected the gripping force of aligners.

Numerous experimental studies have examined how much orthodontic force is needed to move teeth more smoothly; however, no reports have examined this clinically in individual, living subjects. We aimed to develop a method for quantifying the force exerted on individual teeth by an orthodontic wire to measure how loads placed on crowded teeth change dynamically over time. Accordingly, we fabricated a series of dental casts of patients undergoing orthodontic treatment (using optical impressions and a three-dimensional printer), fitted these models with nickel-titanium wire, and subjected them to bending load tests. During leveling, nickel-titanium wire is generally considered to exert a weak force due to its low elastic modulus, with a weak orthodontic force applied over a long period of time due to its superelasticity; however, we found that the actual energy exerted by nickel-titanium wire is also largely affected by other factors (e.g., amount of crowding).

Functional appliances are widely used for promoting mandibular growth by utilizing a construction bite position. We aimed to measure the mechanical load generated by movement of functional appliances and determine the factors influencing this load. Thirteen patients aged 8-12 years were selected for the study, and the load was measured using a previously developed measurement device. To investigate the factors affecting the load, the temporomandibular joint morphology and muscles related to the mandible were examined using cone-beam computed tomography. The standard regression coefficients of the factors affecting the load per millimeter of movement distance were 0.64 and 0.66 for (a) the inclination of the articular eminence and (b) the angle between occlusal plane and posterior temporalis, respectively. Measurement of the occlusal plane to the posterior temporalis and the inclination of the articular eminence were significantly different (p < 0.05). The angle of inclination of the articular eminence emerged as a strong influencing factor. Similarly, the influence of measurements from the occlusal plane to the posterior temporalis was considerable since the posterior temporalis muscle is the most active when the mandible is extended forward. We also found a possible relationship between the occlusal force and load at the construction bite position. To our knowledge, this is the first study to determine the actual load associated with the angle of the temporalis muscle to the occlusal plane, inclination angle of the articular eminence, angle between the occlusal plane and the Frankfort plane, and the angle between the geniohyoid muscle and the occlusal plane. Therefore, mechanical considerations need to be more accurate to facilitate safe orthodontic treatment. (C) 2020 Elsevier Ltd. All rights reserved.

Comfortable bedding is usually designed subjectively because of the difficulty in performing a quantitative evaluation. This paper proposes a quantitative evaluation method of comfortableness of beddings. The bedding shape determining how comfortable an individual may feel in using it depends on the body shape and normal posture of individuals. The internal physical load is expected to relate to the comfortableness of bedding. However, only a few quantitative discussions exist on the relation between the comfortableness of bedding and physical load. This study proposes a new evaluation method of physical load in a relaxed posture. The strain energy of muscles and joints was used as an indicator of physical load. To estimate physical load, a neutral body position was simulated from a natural standing posture and was used as a reference posture with the neutral condition of muscle lengths. By considering individual differences, multiple models of neutral body position were provided. We simulated individual differences of a comfortable pillow height using the proposed models. Physical load in a relaxed posture was varied according to the models. Calculated results show that physical load becomes small when a pillow is comfortable. For both subjective pillow comfortableness and smallness of physical load, there is a similar tendency that the low pillow with the small height difference between head and neck is preferable if the concave depth of back shape of head and neck is small. Moreover, the results show that muscles and joints equally affect the comfortableness of designed pillow. This implies that less total energy required for maintaining the posture contributes to pillow comfortableness.

This study aims to develop a fluid actuated pillow in order to provide comfortable sleep. We proposed an active deformed pillow system by air pressure and its operation system. When inner pressure of the pillow was low, the actuators became flat because stuff inside of the pillow was nothing. Due to the property, sometimes the pillow was uncomfortable. We conducted sensory evaluation of a new actuator which contained urethane form. Almost subjects showed that the pillows with urethane were highly rating. Contact pressure concentration was reduced in case of containing urethane. As a result, actuators which contained urethane improved feeling of the pillow. We plan to select better urethane materials and these thickness.

Comfortable bedding is usually designed subjectively because of the difficulty in performing a quantitative evaluation. This paper proposes a quantitative evaluation method of comfortableness of beddings. The bedding shape de... | Find, read and cite all the research you need on Tech Science Press

This study aims to develop a precise sensor to realize a real-time measurement system for ground motion or dynamic behaviors of large structures. Our proposed sensor requires no electric power supply with using optical interferometry, which has an advantage of long-term measurement. In our previous study, we have confirmed the principle of the sensor. However, the sensor detects the motion of the inside mass part, not the motion of the sensor package. This paper describes an estimation method of the sensor package acceleration for practical use. A mathematical model of the sensor is built with spring-mass-damper system for the estimation of the sensor package acceleration. We compared the estimated acceleration with a result of servo accelerometer, and they showed good agreement. This means the possibility of practical use of the proposed sensor as a real-time accelerometer.

This study develops a new flexible mobile robot using hydrodynamic framework. In our previous study, we developed ciliary actuators capable of generating driving force for the mobile robot. The ciliary actuator operates with one air chamber of bag-like structure. This paper describes a new omnidirectional mobile robot with the ciliary actuators arranged in multiple directions. It is expected that the robot inspects a narrow space that human beings cannot easily enter. To increase mobility performance, this study proposes a lifting mechanism that selects only necessary actuators for a specified movement. This paper demonstrates that the robot successfully moves in all directions and rotates on the spot.

This study aims to develop a precision sensor to realize a real-time measurement system for ground motion or dynamic behaviors of large structures. The proposed sensor uses optical interferometry that requires no electric power, which has an advantage of long-term measurement. This paper describes an experimental study of a MEMS vibration sensor. The result shows that the sensor is able to measure vibration of the sensor mass part. In addition, we have confirmed the possibility of a real-time measurement of the acceleration.

Devices called functional appliances are commonly used in orthodontics for treating maxillary protrusion. These devices mechanically force the mandible forward to apply traction force to the mandibular condyle. This promotes cartilaginous growth in the small mandible. However, no studies have clarified how much traction force is applied to the mandibular condyle. Moreover, it remains unknown as to how anatomical characteristics affect this traction force. Therefore, in this study, we developed a device for measuring the amount of force generated while individual patients wore functional appliances, and we investigated the relationship between forces with structures surrounding the mandibular condyle. We compared traction force values with cone-beam computed tomography image data in eight subjects. The functional appliance resulted in a traction force of 339-1477gf/mm, with a mean value of 196.5gf/mm for the elastic modulus of the mandible. A comparison with cone-beam computed tomography image data suggested that the mandibular traction force was affected by the mandibular condyle and shape of the articular eminence. This method can contribute to discovering efficient treatment techniques more suited to individual patients.

Evaluation of masticatory performance is an important objective of orthognathic surgery. The purpose of this study was to examine masticatory performance including masticatory efficiency using chewing gum containing spherical resinous microparticles before and after orthognathic surgery. We evaluated 18 patients who underwent orthognathic surgery for masticatory efficiency (gum chewing), occlusal contact area (silicone bite) and occlusal pressure (pressure-sensitive sheet recording), and masticatory muscle activity (electromyographic evaluation of the masticatory muscles). Examinations were performed immediately before surgery, and 3, 6, and 12 months after surgery. No significant difference in masticatory efficiency as a standard degree of comminution was found among any of the chewing sites or examination time points, and the patients showed a variety of changes in masticatory efficiency. Masticatory performance excluding masticatory efficiency was apparent after surgical recovery. These results suggest that masticatory efficiency as a standard degree of comminution varies before and after orthognathic surgery on a patient-to-patient basis.

This study aims to develop an intelligent bedding that automatically provides a comfortable sleep condition for each person. This paper proposes a pillow-type device which actively changes its shape and stiffness. The device is composed of multiple flexible actuators which are driven by air pressure. Each actuator has two types of sensors: an internal pressure sensor and five contact pressure sensors. These sensors are used for monitoring the support condition of user's head and neck. We developed a pillow system capable of controlling the internal pressure and contact pressure of each actuator in order to realize a comfortable condition for sleep. The pillow system successfully controlled the center of contact pressure to the target position. To elucidate comfortable and uncomfortable support conditions, pressure distributions on the head and neck were measured by the system. The result indicates that accurate control of the center of contact pressure is important for comfortableness.