Numerical analysis technique for three dimensional sound fields including perforated plates vibrated by sound pressure and mechanical force is proposed. The technique is an acoust - structural coupled analysis technique which is based on boundary element method for sound fields and finite element method for perforated plates. To verify validity of the numerical analysis method, the sound field in the acoustic tube with thin aluminum perforated plate was predicted, and the computed result was compared with experiment. The sound absorption coefficient and the vibration distribution of the perforated plate computed by the present method proved to be good agreement with experimental results. We found that the accuracy of the proposed method is enough and the method is useful for designing sound absorption structure using perforated plates.

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The number of farmers is decreasing and the average age is increasing. The development of autonomous vehicles in an orchard is required because an orchard is usually on a hill or mountain where it is very tough for farmers to work. In this research a new adaptive sliding mode control method is proposed for an unmanned ground vehicle (UGV) by using image-based control with a central catadioptric camera. A central catadioptric camera is very effective since it can make a target keep in the field of vision of camera. The effectiveness of our proposed method is confirmed by experiments.

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Sheet type shear force sensors are developed based on a new detection principle of shearing force. The typical size of one axis shear sensor is a square with 30mm to 100mm in one length, and the thickness is about 1.5mm. Two axis shear force sensor can be made by orthogonally piling up two one axis sensors and integrating together. The shear force sensor is composed of several PVDF strips arranged in parallel and the solid cover plates placed on both surfaces of the PVDF strips. A shear force applied to the solid cover plates is transmitted to the PVDF strips as the axial forces (tensile force and compression force). Several shear force sensors are made for trial purpose, and the performance are examined through experiment.

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Holonomic omni-directional mobile robots are very useful at narrow or crowded areas because of their high mobility performance, and omni-directional mobile robots equipped with normal tires are desired for their ability to surmount the difference in ground level as well as their vibration suppression and ride comfort. Up to the present, the caster-drive mechanism using normal tires has been developed to realize a holonomic omni-directional mobile robot, but some problems have been left. In this paper, we present an effective system to control the electric caster-drive wheel of omni-directional mobile robots, Differential Drive Steering System (DDSS) using differential gearing is proposed to improve the operation ratio of motors. The proposed DDSS generates the driving and the steering outputs effectively from utilizing two motors. Simulation and experimental results show that the proposed system is effective for both of the mobility and energy saving.

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This paper studies locomotion patterns of biological robots by using Q-learning method. Previous studies showed that primitive locomotion patterns were obtained using basic motion rhythm given by its designer. On the other hand, this paper shows that the biological robots acquire its locomotion pattern by itself using a reinforcement learning method. Therefore, advantage of this study is that the biological robots can obtain optimum locomotion pattern related to both its mechanism and actuator characteristics, which means that this method can evaluate the biological robot's mechanism on the view point of the locomotion pattern. We evaluate three different mechanisms of the biological robots which are four legs with a vertebral column, four legs without the vertebral and 6 legs on the viewpoint of energetic efficiencies. The rewards are both advance distance and kinetic energy. Simulation results show interesting results similar to actual living things.

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With a record-low birthrate and a rapidly-growing elderly population, Japan faces a severe demographic challenge, compounded by a chronic lack of nursing care staff. Among nursing care tasks, patient transfer is one of the most physically strenuous tasks. To free caregivers from such heavy physical work and to compensate for the lack of nursing care staff, we have developed two prototype robots, RIBA and RIBA-II, which were designed to come in direct contact with patients and conduct transfer tasks such as lifting and moving a patient from a bed or the floor to a wheelchair and back. This paper, focusing on RIBA-II, describes the motion design, handling method, safety measures, as well as the verification experiment conducted on healthy subjects. RIBA-II, who's whole body including the joints is covered with soft materials to realize a safe and easy contact with humans, has the ability to lift up a human up to 80kg with a certain safety factor from the floor and transfer him/her to a normal wheelchair with armrests. The robot is not an autonomous one but a robot operated by a caregiver to ensure safety. When conducting a transfer task, the caregiver handles the robot by stroking the rubber tactile sensors installed on the robot arms and, at the same time, confirms safety. The purpose of the robot is not only relieving caregivers from heavy physical works but also to replace the transfer task conducted by two caregivers by one robot and one caregiver. The feasibility has been demonstrated by the verification experiment as described in this paper.

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A deviation of reality from our prior expectation causes positive or negative emotions such as unexpected pleasure or disappointment depending on the condition. Although recognition of this psychological phenomenon has much potential in the design of a product's emotional quality, i.e., that which evokes the customer's specific feelings, impressions, or emotions, this factor is largely unexplored. In the transition from prior expectation to posterior experience, we often observe switching sensory modalities, such as from vision to touch. In this paper, we discuss the differences in emotional quality between different sensory modalities in the context of shifting from visual expectation to somatosensory experience. As a case study, we investigate the effects of an object's surface characteristics on the deviation from visual expectation in the context of “lifting an object”. In this context, the sensory modality shifts from vision to touch and vision, i.e., we see and then lift a target object. We conducted an experiment using cylinder-shaped objects of equal weight with different surface characteristics such as brightness, roughness and gloss. The experiment consists of three phases. 1) We asked eight participants to give their impressions by only looking at the object using adjectives and onomatopoeias, 2) we asked them to lift the objects and recorded their grip force, and 3) we conducted the same evaluation as the first phase except that the participants were allowed to pick up the objects. The results show that the deviation from visual prediction regarding object massiveness and surface roughness can be observed using redundant grip force differences, and that this deviation affects a posteriori tactile emotional qualities such as tactile feelings. With the result, we discuss the need to consider such deviations in emotional quality design.

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The orthogonal cutting method of soft material with acrylic rubber and graphite was investigated by measuring the deformation of the material and the chip at several conditions in temperature. The experimented rake angle and temperature were 10, 30, 55 and 68 degrees, and -5, 0, 10, 15 and 20 degrees Celsius respectively. The mode of the deformation of the work during cutting changed from the shearing to hitting wedge mode at the rake angle higher than 55 degrees. The thrust force became negative at the higher rake angle. It was suggested that the increasing force to push up the work by the rake face. The tool with double-deck on rake face was found to be effective to control the thrust force. It was found that the surface of the chip become adhesive and rough with an increase in temperature. The chip was contacted on the rake surface of the tool widely at 20 degrees Celsius. It was suggested that that the increase of the friction force on the rake face result in rougher surface and more adhesive of the chip.

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