An investigation was conducted based on robot contest at a junior high school. Three kinds of rules have been decided by the teacher responsible set a national meeting. The robots were made in the time of the Technology Education course and club. Though the teaching content and methods are various, in many cases, the study of robot is studied by the elective subject in Technology Education courses. Problems were found by the investigation in the teaching method, learning time, production costs, teaching content, evaluation method.

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Leonardo da Vinci is not only famous as the artist who painted master pieces such as “The Last Supper” and “Mona Lisa”, he is also a great scientist and engineer. He left records of many original scientific inventions and explorations in books now known as Leonardo's Codices. These codices include anatomical charts, mechanical equipment, civil engineering concepts, and drawings related to architecture, astronomy, botany, and so on. The contents of these Codices are interesting for beginners who are studying mechanical engineering, although beginners are not used to recognizing a solid from a drawing.Therefore, models were reconstructed from the drawings in these codices, to be used as teaching materials for the study of mechanical engineering. In a lecture as part of a mechanics course, it was possible to generate an interest in mechanical engineering among beginners who studied the mechanics by using the reconstructed models. Similarly, an opportunity to consider the field of mechanical engineering was given to students of primary schools, junior high schools, senior high schools, and their parents, by the reconstructed models presented in the DA VINCI Festival at Toyama Prefectural University.

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This paper shows a technical education program for high school students, which consists of image information processing, stereo vision technology and control experiments of a mobile robot with the stereo vision system. Education results show that this technical education program can give excellent effect to obtain both hardware and software technology and also to obtain control experiences of actual robots. In addition, this program has the possibility to give the high school students an interesting experience of both constructing a robot and its programming, that is certified by questionnaires of the students after the program. Finally, these education results indicate that this education program is an effective education system for high school students to obtain system technology including software and hardware technology.

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In recent years, 3-D CAD/CAE system has come into wide use in Japanese manufacturers. So, engineering education is required to respond to the trend quickly and effectively. The program shall be enough for undergraduate to acquire a basic level of proficiency in skills needed for machine-designing using 3-D CAD/CAE system. In Meisei University, 150 junior students of mechanical engineering department study computer-aided machine-design with 3-D CAD/CAE system. A model Stirling engine is designed in the first semester and a small reciprocating air compressor is designed in the second semester. Students gain experience of performance and strength calculation, formation of three-dimensional image of parts, stress analysis, collision and clearance check, assembly of parts, movement check, and making drawings for manufacture. The effect of our education was confirmed by the questionnaire survey done to the students.

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3D-CAD system has been used in practical product design to realize simultaneous engineering and also to improve productivity. Although 3D-CAD is a widely used and highly effective tool in mechanical design, it also has its drawbacks : mastery of 3D-CAD skills is rather complex and time-consuming. In an attempt to simplify the learning process and cut down on learning time, we have developed training programs for mechanical design such as a concept making, a family tree and a team design method, and e-Learning contents for the 3D-CAD operation skills. The effectiveness of these training program and e-Learning contents has been confirmed by cooperative activity between an enterprise and a school in mechanical design education.

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In order to help the understandings of the working principles of an internal combustion engine, the multi-media contents were developed and used for the lesson of the machining practice exercise. Moreover, the learning effect of the contents was examined with the aid of the drills and questionnaires. As the result of the examinations, it follows that the rate of the right answer of the drills was about 60% with the use of the drawings of the principle of an engine working, and that its rate of the drills turned to about 80% after e-learning training. In the case of the Diesel engine lesson, the learning effect was appeared remarkably in comparison with the Otto cycle engine.

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An environment where Japanese industry has been paid with respect is changing tremendously due to the globalization of economics, where other Asian countries are undergoing economical and technical development as well as advancing in information technology. With acceleration of manufacturing bases relocating abroad, industrial hollowing out is happening; hence effort to transfer the technology and the design knowledge of machine design in a company is becoming an important subject. For example, in the design of custom casting products, a designer who is lacking in casting knowledge may not be able to produce a good design. In order to obtain a good design and manufacturing, it is necessary to equip the designer and manufacturer with a support system related to casting process or so called, knowledge transfer and creation system. This paper proposes a new educational support system for manufacturing technology; where machine design, which requires added values such as advanced technology, high quality, and short delivery time, is taken as an example and both its explicit and tacit knowledge are cooperated by using synchronized multimedia and immersive virtual environment.

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In recent years, decreasing skilled workers have become a big problem in our country. Therefore a method or system is necessary in which unskilled workers can obtain high level skills such as crane operation on creating a mold efficiently. Since OJT (On-the-Job Training) is one of the main methods of knowledge transfer and job training, however it is limited due to decreasing young workers and aging of skilled workers. In this paper, the VR-based training system for crane operation is shown. We conduct the experiment that trialists use the system. As a result, the effectiveness of the VR-based training system for a crane operation is considered.

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The authors proposed a new method which could easily and precisely detect the contact point position between the rail and the wheel under the critical condition of wheel climb derailment. As the result of the experiment using the above mentioned method, they found that the position was variously changed according to rail attack-angles and wheel lift-up values from the rail tread. The next, employing the contact point position, a new conception was proposed to theoretically calculate the wheel lift-up value from the rail tread when a wheel climb derailment occurred. Using a model track and a model truck, experimentation was done to examine the difference between the theoretically calculated value and the practically measured one on the wheel lift-up value. The result obtained was very much in agreement with the theoretically calculated value and the practical lift-up one.

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In vibration design, we need to estimate the damping ratio to calculate the dynamic response of a structure. In particular, an estimation of its probability distribution is important to carry out so-called probabilistic design. For this paper, we developed an estimation method using the Bayesian approach to generate the probability distribution of the damping ratio from a vibration test with a small sample size. The Bayesian approach has special significance to engineering design, where available test data is invariably limited, for the approach can systematically incorporate subjective judgments based on experience or indirect information with observed data. We supposed that the probability distribution of the damping ratio has a normal distribution. Therefore, we applied the Bayesian approach to estimate unknown parameters of the distribution. In addition, we compared this method with a method of moments classified as a classical estimation and investigated the influence of sample size by conducting an evaluation test. With the results of our analysis, we came to the following conclusions. First, he true standard deviation of the damping ratio is less than 0.4, and the prior distribution of the standard deviation ranges between 0 and 0.5. (1) The estimated probability distributions determined by the Bayesian approach and the classical approach almost fully agree across more than 40 specimens. (2) The Bayesian approach provides good agreement, less than 10 percent error, with a true standard deviation for approximately 10 specimens. Even though the prior distribution of standard deviation ranges between 0 and 1.0, almost the same accuracy is obtained for approximately 10 specimens.

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This paper proposes a structural optimization method for obtaining mechanical structures that maximize structural stiffness, based on the level set method. First, the basic details of a structural optimization method using the level set method are briefly explained, and an optimization problem that addresses the minimum mean compliance problem is formulated. Next, an optimization algorithm is constructed based on this formulation. In this optimization scheme, a new re-initialization method is proposed, in which a level set function is re-initialized, based on a zero level set surface. This re-initialization method can easily deal with level set function singularities, and can be applied to non-structural meshes. A second new method is also proposed in which the level set function is modified to satisfy a volume constraint while preserving topology of the structure being optimized. By using these two new methods, structural optimization problems can be solved using the finite element method rather than the finite difference method. Finally, several examples are provided to confirm the usefulness of the proposed structural optimization method.

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This paper describes a new Dynamic Absorber Suspension (DAS) structure which has a significant damping effect for the flow-induced sway mode and second torsion mode. First we designed the DAS structure for a practically used suspension by Finite Element Analysis. From frequency response function of DAS, we found that magnification factor of sway mode can be reduced to 14 dB, and that of second torsion mode is 5 dB. Next, we fabricated the DAS and measured the frequency characteristics by laser Doppler vibrometer using a hydrostatic air-bearing jig and a 3.5 inch disk spindle. As a result, we found that the DAS has a remarkable damping effect on the sway mode and second torsion mode compared with a conventional suspension with a damper sheet.

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Many structures are installed on supports in industrial facilities. The damage by amplitude increases with the coupled vibration is shown. The response magnification is obtained from natural frequency and damping ratio of the coupled system in the seismic design. Therefore, the natural frequency and damping ratio of the coupled system are required. The natural frequency and damping ratio of support and structure are obtained in initial design or vibration test. However, the natural frequency and the damping ratio of the coupled system are not easily obtained. The natural frequency of the coupled system can be calculated from theoretical equation, but the damping ratio cannot be easily calculated. In this study, the equation to calculate the damping ratio of the coupled system with Rayleigh damping is shown. The equivalent damping ratio without Rayleigh damping is estimated.

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This paper deals with a countermeasure against pattern formation phenomena generated on thin sheet winder using dynamic absorbers. The thin sheet is widely used as paper, aluminum, etc. Pattern formation phenomena of the wound sheet sometimes occur in operation because of the viscoelastic characteristics of the sheet. The pattern formation phenomena lead to a fatal damage on the thin sheet. This problem is similar to the other pattern formation phenomena, for instance, polygonal deformations of the smoother roll of paper making machines and pattern formation of the elastic yarn of textile winding machines. The authors conducted experiment to generate the pattern formation using experimental apparatus, and theoretically analyzed to clarify the mechanism of the pattern formation phenomena considering the elastic deformation of the rolls. They also theoretically examined the countermeasure to suppress the phenomena by attaching some dynamic absorbers. The effectiveness of the tunable dynamic absorbers was confirmed by the theoretical analysis, and an example of the tunable dynamic absorber was introduced.

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The vibration characteristics of CFRP laminated composite shells were investigated experimentally and compared with those of isotropic shell. The laminates were composed of four-layered CFRP prepregs for angle-ply (unsymmetric laminate) and of five-layered ones for cross-ply (symmetric laminate). The isotropic shell with the same size as the composite shells was made of steel. In the experiment, these shells were mounted on a vibration table with clamped-free end condition, and excited horizontally by white noise. The natural frequencies and mode shapes were identified by modal analysis using STAR-system Software. The obtained frequencies of the shells were plotted as a function of circumferential wave numbers for each given axial wave number. It is found that the frequency curves of the laminated composite shell and the isotropic one cross at some circumferential wave number.

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This paper describes dynamic analysis of micro-parts feeding using a saw-tooth surface. We have proposed a unidirectional feeding using a saw-tooth surface with simple planar and symmetric vibration. Unidirectional feeding is realized by different contact conditions along positive and negative directions. We need to consider not only the inertial force but also the adhesion force when micro-parts are tens or hundreds micrometer in their size. The adhesion forces change according to the contact condition between the micro-parts and the feeder surface. We propose two formulations of contact conditions. The first approach introduces directional friction coefficients. The second approach introduces the identification of adhesion force by estimating the maximum static friction of a micro-part on a fabricated surface. We formulate a dynamics model when the contact condition is defined as directional friction coefficients. Then we identify parameters in the model by conducting feeding experiments with various driving condition of the feeder. We analyze the driving force that changes according to the relative position between the micro-part and the saw-tooth. We derive a dynamics model including the adhesion force. We conduct numerical simulations using the derived model. We then compare the simulation results and feeding experiments with various elevation angles of saw-tooth surface to verify the proposed dynamics model.

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This paper deals with decrease of the noise caused the chain drive using new sprocket wheel with slits. A characteristic of frequency and main causes of the noise are investigated from the noise of the chain drive. The natural frequency of each element of the chain drive is calculated by using NASTRAN for windows which is finite element method software. The analysis results are compared with the noise experimental results and the impulse response experimental results. The relation between the frequency result of the noise experiment and the natural frequencies of each element of the chain drive became clear. From these results, it is important to decrease the sprocket wheel noise for the chain noise. The new sprocket wheel which put in the slits is proposed. The measurements of the slit put into a sprocket wheel are determined using the stress analysis of NASTRAN. The decreasing of the noise of the chain drive by using the new sprocket wheel with slits is tried. The sprocket wheel with slits succeeded in decreasing the noise by the elastic deformation of the tooth of the sprocket wheel.

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The vibration suppression becomes very important for designing the helicopter blades to ensure the comfortability and safety. Now-a-day, the pendulum absorbers and others are adopted for the purposes to reduce the vibration of the rotor blades. But, the drawback is that the dimension of the pendulum absorbers is determined by the anti-resonance concept based on the linear theory, and also its characteristics are not analyzed completely. In a Helicopter, periodic forces act on the blades due to the influences of the air thrust. These periodic forces act on the blades with their integer multiple of the rotational speed of the rotor. We have proposed a two-degree-of-freedom model of the rotor blades and the pendulum absorbers, and it clarifys the vibration-proof effect of the pendulum absorbers on these forces.

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The author has proposed a regulator-type adaptive nonstationary control (ANSC) method using time-varying Riccati equations (TVREs). ANSC method generates the solutions of TVREs and the responses of a controlled object simultaneously. The time-varying feedback gains are obtained by real-time computations in actual implementations. Therefore, ANSC method can realize some adaptive control based on varying parameters of a controlled object. The regulator-type controllers are applicable to Position-To-Position control problems. In mechanical structures such as information precision machinery, the switching from a velocity servo controller to a position servo controller is often utilized. ANSC method can not be applied to that case. Then, this study proposes an adaptive nonstationary servo control (ANSSC) method based on the idea of ANSC method. ANSSC method realizes a unified design of both the servo controllers and the smooth mode switching. Its effectiveness is verified theoretically and experimentally by applying the method to a positioning control problem for the system consisting of an X-Y table and a flexible structure on the table.

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In this paper, we examine the anxiety at utilization of wheelchairs. When the human use wheelchairs, from the influence of environment, the human feel a sense of unease. In particular, when the human go down slopes using wheelchairs, the human feel a sense of unease. The sense of unease is under influence of the organ of vision and the vestibular organ. In this paper, when the human go down slopes using wheelchairs and the influence of the organ of vision is eliminated, whether or not, the declivity angle for human to feel the anxiety can be estimated. It is clarified that the declivity angle for human to feel the anxiety can be estimated with relatively high accuracy.

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In this paper, we give the parametrization of all robust stabilizing modified repetitive controllers for single-input/single-output systems. The basic idea to obtain the parametrization of all robust stabilizing modified repetitive controllers is very simple. If the repetitive controller stabilizes the plant, then the repetitive controller must be included in the class of all robust stabilizing controllers for the plant. The parametrization of all robust stabilizing controllers for the plant, which is not necessarily modified repetitive controllers, are obtained by solving an H∞ control problem based on either the Riccati equation or on a Linear Matrix Inequality. The parametrization of all robust stabilizing controllers for the plant includes a free parameter, which is stable. That is, robust stabilizing modified repetitive controllers can be designed using the free parameter in the parametrization of all robust stabilizing controllers for the plant. Using this idea, we obtain the parametrization of all robust stabilizing modified repetitive controllers. The limitation on the low pass filter in the repetitive controller that exists in the robust repetitive controller is clarified explicitly. Finally, a numerical example is illustrated to show the effectiveness of the proposed parametrization.

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In this paper, we examine PID (Proportional-Integral-Derivative) control using model driven control for stable plants. PID control systems work as one of powerful methods for controlling several plants. However, PID control remains a difficulty. That is, when P-parameter, I-parameter and D-parameter in the PID controller are adjusted using previously proposed methods, the admissible sets of P-parameter, I-parameter and D-parameter, which guarantee the stability of PID control system, are related each other. Therefore if P-parameter is changed, the admissible set of I-parameter and D-parameter which make the feedback control system stable is also changed. If the admissible sets of P-parameter, I-parameter and D-parameter are independent each other, then we can easily settle P-parameter, I-parameter and D-parameter in the PID controller to achieve desirable control specifications. However, no paper gives the admissible sets of P-parameter and I-parameter which are independent each other. The purpose of this paper is to overcome this problem and propose modified PID control systems such that the stability of control system is guaranteed and the admissible sets of P-parameter, I-parameter and D-parameter, which guarantee the stability of PID control system, are independent each other. The modified PID control system is built based on fusion of the idea of the model driven control and the parametrization of all stabilizing controllers for stable plants. A numerical example is illustrated to show the effectiveness of the proposed method.

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Recently, data traffic for satellite communications is increasing rapidly, due to the various new purposes besides the conventional voice phone and facsimile. For the reason, it is necessary to realize high frequency communications, which is assured by high accuracy of tracking control of an antenna. This paper aims at the accuracy improvement of conventional tracking antennas by introducing H-infinity control. In this paper, the basic characteristics of tracking antenna are investigated by experiments and the model of the antenna for controller design is established. Based on the model, a H-infinity controller is designed and implemented to the antenna. Experimental results show that the tracking accuracy can be improved to ±0.25 [deg], which is four times higher than that by the conventional controller.

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In this paper, we studied the influence of the gas flow on the characteristics of the quartz odor sensor experimentally. The AT cut quartz odor sensor was used to decrease the noise of temperature and the dimethyl sulfide was used as a target gas with discomfort odor. Moreover, the cholesterol film was used as the sensing film deposited on the quartz surface for the detection of the dimethyl sulfide. The experimental results are summarized as follows. 1) The flow velocity has a strong effect on the performance of the quartz odor sensor. Moreover, the increase in the gas velocity has an effect to decrease the frequency change of the quartz odor sensor within the present experimental conditions. 2) The gas velocity component parallel to the quartz surface can deform the curve of frequency change with time strongly and degrades the sensitivity of the quartz odor sensor.

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Two kinds of sheet type impact force sensor are developed : frictionless impact sensor and multi-contact impact sensor. Sensor structure consists of a main body and cover member. Main body of the sensor is made from piezoelectric film (PVDF) and silicon rubber. Frictionless impact sensor is wrapped by a flexible cover member. Oil layer is placed in between the main body and cover member. Multi-contact impact sensor has solid cover plates on both surfaces of the main body. The solid cover plates play a role to transmit impact force to main body by a mechanism of multi-contact loading. The performance of the impact sensor is examined through experiment by applying several impact forces using hand hammer, hand-grip and screw driver head pressing. A good linear relationships between applied impact force and sensor output are observed for both sensors.

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A three-dimensional distribution of magnetic filed is considered to obtain an analytical model of the magnetic reluctance of rectangular iron-cores whose ends face to the working airgaps in a magnetic system. The reluctance model is compared with a simple model based on the two-dimensional distribution to check the validity of this simple model for the effects of the length of iron core. First, the magnetic field is solved under an assumption that the magnetic intensity is uniform and perpendicular to the end surfaces. To obtain an analytical solution, however, a natural condition is neglected that the magnetic intensity is uniform on the side surfaces parallel to the longitudinal direction. Also, the concept of generalized functions is applied to discuss the convergence of an infinite cosine-function series; hence the result obtained is an approximation. Next, the magnetic reluctance is obtained from the magnetomotive force along the iron-core surface divided by the magnetic flux. The reluctance is expressed with two parts : a term corresponding to two-dimensional model and a term with a function of the iron-core length. Approximate equations are presented to avoid poor convergence of double infinite series, and numerical examples are given to show the results.

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Maglev pump is widely requested for artificial heart or chemical industries. Hybrid magnetic bearing is recognized as high efficient one even with wide airgap and suitable for such applications. This paper proposes two types of hybrid magnetic bearings for canned maglev pump. One is the standard (STD) type and another is the internal permanent magnet (IPM) type. Both types are analyzed using the finite element package and designed. Then the experimental setups are made and their fundamental characteristics are explained. The results show stable levitation and promising characteristics for the practical use.

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We discuss a placing motion of a grasped object by a robot hand equipped with a flexible sensor on the finger. The aim of this study is to realize a quick placing motion with the impulse force between the object and the floor small. To derive a dynamic model of the motion, we consider the deformation of the flexible sensor occuring when the hand grasps the object. The dynamic model represents the relationship between the impulse force and an approaching trajectory of the robot hand to the floor. From this model, we can obtain the trajectory of the hand which ensures that the impact force is less than the object's mass. The validity of the model and the effect of the sensor's flexibility are examined through simulation. We then experimentally confirm that the robot hand puts down the object without an excessive impact force by using the obtained trajectory.

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Multi-robot system under decentralized control has become to attract international attention as a solution for the difficult and complex tasks. Decentralized systems are expected to have flexibility of architecture and fault tolerance. But these systems are not suitable for the tasks that their order of work have to be considered, because in many cases, each robot's behavior and whole system's purpose are hard to match. This paper describes the algorithm for multi-robot system to solve such 'sequential' tasks using idea of social choice theory and petri net. The introduction of multi-robot system that is developed in this research is also described in this paper.

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This paper discusses a method to find a collision-free path of industrial robot manipulators in a known environment where collision detection between manipulators and obstacles is necessary. The configuration of robot manipulators is represented based on the concept of configuration space (C-space) whose coordinates correspond to degrees of freedom of manipulators. Geometric criteria of collision between two dimensional manipulators and obstacles are formulated and estimated in each region of segmented C-space by using interval analysis. Based on this estimation, the shortest path from given starting point to end point in C-space is obtained by Dijkstra algorithm through the series only of the feasible regions where it is guaranteed that manipulators do not collide with obstacles. Validation of this algorithm is tested by a couple of numerical examples.

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This paper proposes a control algorithm for pace gait of a quadruped walking robot, using a passive dynamics autonomous control algorithm (PDAC). The PDAC realizes an efficient motion based on the intrinsic dynamics of a robot. This paper first calculates an energy consumption of the pace and a crawl gait at various walking parameters such as a stride length and a walking period. The optimal walking parameters are obtained for each gait at various walking speed in the simulation and their parameters are confirmed by applied to an experimental walking robot. The trend of the energy consumption transition measured in the experiments are similar to those in the simulation. For example the consumption energy of the pace gait becomes less than that of crawl gait when a walking speed becomes relatively high. As a result, quadruped walking parameters corresponding to the desired walking speed such as the type of gait, the stride length and the walking period are designed on the energy-consumption-basis.

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Switches on the steering wheel can be handled more easily and safely with less glance time than those at the instrument panel. In our former study, following result was presented, “6 switches on the middle and upper area of steering wheel are more easily handled than those on the lower area as used in the cars available in the present markets.” In this study, considering that the number of steering wheel switches is expected to be increased, maneuverability of 8 switches on the middle area was studied : (a) 8 on obverse side only, (b) 6 on obverse side and 2 on reverse side and (c) 4 on obverse side and 4 on reverse side. No difference can be found between (a) 8 on obverse side only and (b) 6 on obverse side and 2 on reverse side. Both (a) and (b) were better than (c) 4 on obverse side and 4 on reverse side.

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This study was intended to construct and then evaluate rear-end collision preventing systems that support braking operation process of the following vehicle's driver in an attempt to prevent rear-end vehicle collision. The system provides the following vehicle's driver with visual information consisting of three components, (1) an area of red brake lamp in proportion to the degree of the deceleration of own vehicle, (2) an area of red brake lamp in proportion to the degree of the deceleration rate required for the following vehicle, and (3) warning signal by blinking lamp. Using the driving simulator in this experiment, braking operations of the following vehicle's driver taken in response to the braking maneuver of the leading vehicle with the rear-end collision system on board were measured. As a result, in the experiment of the system to provide signals calling for the necessary deceleration efforts, the headway distance between the two vehicles was set at 20m with 7m/s² of deceleration velocity, it was found that the braking operation started faster by 0.1s-0.2s and the relative velocity was reduced by about 30%, thus leading to improvement of about 60% in operation of preventing the rear-end collision compared with the vehicle with no such system on board. It is considered that the improved effect resulted from the fact that recognition and judgment of the drivers in the braking operation were supported by the system.

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This paper describes the cooperative characteristics of carrying an object by two humans and its application to the control of a robot for performing the cooperative task with a human. First, the cooperative task is modeled on one dimensional horizontal motion and the experimental condition for the analysis of the cooperative motion by two humans. Secondly, variable damping characteristics of the human arm are found in the experimental cooperative motion and are expressed as an optimal trajectory of the damping factor using a performance index which evaluates both the change speed and the magnitude of the damping effect. Thirdly, a variable impedance control method of a robot is constructed using the optimal trajectory and it is shown that a human manipulates the robot like as human and human cooperation. Finally, it is found that even if one of the parameters making the optimal trajectory changes to high values, the smooth cooperation between the human and the robot keeps successfully.

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This paper proposes an intelligent room in which a person can operate home appliances naturally by gestures. Cameras with pan-tilt and zoom functions are set in the room, and the system is realized by using image information. Intention of operation and 3D position of the operator are recognized by detecting his/her hand waving, and the cameras are zoomed and focused on the operator's waved hand and the skin color is registered. The hand and finger regions are extracted by using the color information and gestures with the hand and fingers are recognized. This method is robust for the change of skin color because color information is not necessary at the stage of detecting hand waving and the skin color at the moment is used. A target appliance is chosen by recognition of pointing direction by the hand and operations of the appliances such as switching on/off, turning up/down of volume and changing channels are realized by recognizing the number of fingers and the hand's motion.

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The development of assistive technologies has an important impact on the user's activities of daily living and social participation. However, assistive technology identifies persons with disabilities. In this paper, the psychological effects of using a mobility aid were considered before forming the concept of a new device. To identify detrimental factors, a qualitative research approach was adopted in a study on 12 older persons. The investigation revealed that older persons had a dilemma in using mobility aids between maintaining body functions and extending mobility activities. In addition, there are two sides to the dilemma, the function and the image of the body. The process to assuage these dilemmas was clarified and a psychological model was built up. The generation process of the psychological conflict obtained from qualitative data was revealed by modeling details and taking movement, body function and body appearance into consideration. Development of useful assistive technology will be improved by taking account of compositive observational study on the body, the life and the psychological situation of older persons.

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To determine the accuracy of foot position sense in the means of foot placement, young adults were asked to place either medial edge or lateral edge of their feet along the base line on the floor as close as possible, and the edge of placed feet were scanned by using laser displacement gauge. From the collected data, constant error, the distances between the edge of placed feet and the base line on the floor, and absolute error, the absolute distances between the edge of placed feet and the base line on the floor were defined and compared between the medial or lateral trials, and dominant leg or indominant leg. The statistical analysis showed significant differences of constant error between the trials only. The trials to place their medial edge tend to place their feet away from the base line, and the trials to place their lateral edge tend to place their feet in to the base line. These results indicate that we tend to expect the position of our feet more medially than actual, and these discrepancy may be one of a reasons of tripping or banging of our feet to the obstacles while walking.

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This paper proposes a new method which is called as Adaptive Range Particle Swarm Optimization (ARPSO), based on Adaptive Range Genetic Algorithm. That is, the active search domain is determined by using the mean and standard deviation of each design variable. In general, multipoints methods are utilized in the field of evolutionary computation. At the initial search stage it is preferable to explore the search domain widely, and is also preferable to explore the smaller search domain as the search goes on. To achieve this objective, new parameter which determines the active search domain is introduced. This new parameter gradually increases as the search goes on. Finally it is possible to shrink the search domain. The way to determine the maximum value of this new parameter is also shown in this paper. The optimum solution with high accuracy and a little number of function calls is obtained by proposed method in compared with original Particle Swarm Optimization. Through numerical examples, the effectiveness and validity of proposed method are examined.

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A new optimization method for the design of axial turbine stages is described, which can search for the global optimum solution and decrease the number of iterations. In order to realize high efficiency in turbines, it is necessary not only to apply the latest technology to turbine apparatus, but also to optimize various design factors using conventional technology for the purpose of cost effectiveness. The feature of the new method include creating orthogonal arrays and changing the level value of design factors for every search step. The orthogonal array is selected based on the number of factors & levels, and the level values are changed based on the trend of the optimum solution. As a result of applying the method to the optimum design of turbine stages, it is shown that the method can search the global optimum solution at approximately one seventh of the iterations of Ga or SA.

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Two problems were numerically analyzed for an unmanned aerial vehicle for aerial photography. Height control in backside of drag curve was studied, using optimal regulator and optimal control theories. It was shown that the optimal solution without limitations of terminal velocity was different from that with limitations. The optimal regulator from a given initial lateral deviation going back to the reference flight course was also presented. When a large roll angle is allowed, the wider camera view is lost but less deviation from the reference course is realized. The design trade-off was then discussed between camera view and deviation from the reference flight course.

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Magnetic particles form chain-like clusters in a magnetic field. These chains are used to supply toner particles on a photoreceptor drum in the two-component magnetic brush development system used for high-speed and/or color laser printers. Characteristics of chains influence image quality of the printer. Although experiments had been performed in low magnetic field, characteristics in the high magnetic field are necessary to investigate actual performance of the system and thus an experiment on the chain formation has been performed in the ultra high magnetic field created by a superconducting magnet. It has been clarified that the chain length first increased and then decreased in accordance with the increase of the magnetic field. The result has been confirmed by a numerical calculation with the Distinct Element Method that included the contact force between particles, the gravitational force, and the magnetic force due to the field created by the coil and adjacent magnetized particles. Lastly, it has been discussed that the static stability of chain was determined by a minimization principle of the potential energy that consists of the gravitational and magnetic potential energy.

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The novel mechanism CVT (Shaft Drive CVT, S-CVT) was developed by the authors. The improvement of power to weight ratio, namely the increase of transmitted power with downsizing and lightening of the transmission is important applying the S-CVT to automobiles. The concave disk/roller to reduce the slip ratio were devised and their effect to improve the efficiency was confirmed by the experiment, but the contact pressure was a little large and limited the torque capacity. The new curved disk/roller named the zero-spin disk/roller was devised in this paper. The spin decreased to less than 0.9% at all speed ratio and the contact pressure was also decreased comparing with the concave one. The optimum design of zero-spin disk/roller to satisfy the torque capacity of 150 Nm was achieved using the power to weight ratio as the evaluation function. The allowable Hertzian pressure is set as 4 GPa. The power to weight ratio of zero-spin and concave disks/rollers becomes 2.3 and 1.7 kW/kg, respectively. It is improved 36% and the effectiveness of zero-spin disk/roller is confirmed.

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This study discusses a robot hand which can be mounted on the human hand to rehabilitate damaged fingers or to assist finger motion. Ordinary robot hands tend to be heavy and large, because they require to mount an actuator on each joint and to use many actuators. Thus, the robot hands are not appropriate to be mounted on the hand. This study notes that human hand grasping any objects composes parallel mechanism. As the parallel mechanisms can arrange the actuators on the base, their moving parts are simple and lightweight. Thus, we propose the wearable robot hand using parallel mechanism. The chains of the proposed mechanism are fixed to the tips of the fingers and the mechanism uses the grasped object by fingers as the output link. When human hand equipped with the proposed hand grasps an object, the proposed robot hand composes a parallel mechanism. Then, human fingers can be operated in a variety of motions. Furthermore, the restraint of the fingers by the wearable robot hand can be easily taken off by releasing the grasped object. Thus, human hand will be safe with respect to unexpected motion of the wearable robot hand.

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In this paper, we discuss morphing using a polyharmonic function. A method for creating implicit surfaces is described using a polyharmonic function (radial basis function) to form complex solid models from scattered surface points. The conventional method of constructing CSG model use simple solid primitives. In the presented method, many quite complex solid primitives can be used, because only surface points are used for boundary representation. The presented methods contain the conventional Boolean operations on solids and new Boolean operations for points. This method uses Poisson's equations and a polyharmonic function, which is a type of thin plate function. Thin-plate solution has several problems. The first problem is that O (n²) computations are required to solve the system of equations. The second problem is that a small change in even one constraint affects the entire resulting interpolated surface, because every known point affects the result. However, thin-plate interpolation is often used in computer vision, because surface patch is not necessary. In order to investigate the efficiency of this method, several examples are given.

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In this paper we investigated relationships between creative mental set and rule-violating action with a questionnaire for 218 hospital workers. We have executed an exploratory factor analysis. These results revealed five factors for creative mental set; curiosity, minutiae, inquiry, sensitivity and courage, and three factors for rule-violating action; regulation rule violating, local rule violating and self-style. Correlation analyses and multiple regression analysis indicated a negative relation between curiosity and regular rule violating. Also, negative relations between minutiae, inquiry and local rule violating action was yielded. Furthermore, an average score of local rule violating is significantly higher in [high and excellent care] climate than those in other climates by analysis of variance. These results are integrated for a necessity of safety rule. That is, an unnecessary rule should be arranged and content of absolutely necessary rule has been continuingly improved by invention of working sites.

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While reuse is an effective life cycle option in terms of reduction of environmental loads and conservation of value of circulation, reuse has inherent difficulties. Our naive questions include why reuse of electric home appliances seems impossible while that of photocopiers succeeded. This paper clarifies that a critical factor for successful reuse is to balance supply and demand of reusable products and components. For representing this factor, this paper proposes an index named “marginal reuse rate, ” which indicates upper limit of reusability from the viewpoint of the balance. By using the marginal reuse rate, this paper analyses reusability of single use camera, photocopier, and automatic teller machine (ATM). These analyses clarified that the marginal reuse rate depends on the relation between sales period and product's lifetime and effective measures for increasing reusability differ according to the relations; namely, prolongation of the sales period for shorter life products, part commonization design among generations for middle life products, and controlling sales and disposal distributions for longer life products. The marginal reuse rate indicates that design of life cycle, in addition to product design, is indispensable for successful reuse. In this sense, the analysis with the marginal reuse rate is an indispensable tool for appropriate life cycle design.

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Humans obtain some tactile feeling when they touch and rub objects with their fingers, which should be associated with some information about the objects. It means tactile information exists in such tribological actions of their fingers inevitably. In the present study, discrimination of particles has been investigated by using tactile information in an artificial system. Two kinds of time-series signals, i.e. normal and tangential fluctuations, were obtained experimentally when two silicone-gum specimens were rubbed with sands between the surfaces of specimens, in which the sands with sizes of 180-710 1.im were classified into five samples by sieves. The particle diameters of samples were found to be correlated with two quantities obtained from the time-series signals ; one was the normal elastic recovery between before and after rubbing, and the other was the weighted mean frequency of dominant elements appearing in the spectrum of tangential fluctuation. By using the relationship between the two quantities and the particle diameters, the artificial system showed an ability of discrimination comparable with human subjects.

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Discrimination of particles has been investigated by using tactile information in an artificial system. Two kinds of time-series signals, i.e. normal and tangential fluctuations, were obtained experimentally when two silicone-gum specimens were rubbed with sands between the surfaces of specimens, in which the sands with sizes of 20-710 μm were classified into nine samples by sieves. The particle diameters of samples were found to be correlated with two quantities obtained from the time-series signals; one was the normal elastic recovery between before and after rubbing, and the other was the weighted mean frequency of dominant elements appearing in the spectrum of tangential fluctuation. By using the relationship between the two quantities and the particle diameters, the artificial system showed an ability of discrimination comparable with human subjects. Information of the size of sands appears in three ways. In case of larger-size samples, it appears strongly in the weighted mean frequency with lower-range frequency. On the contrary, it appears strongly in the elastic recovery for middle-size samples, and in the weighted mean frequency with higher-range frequency for smaller-size samples. By considering such characteristics, an algorithm has been constructed for discriminating the all samples with a higher accuracy, which has a similarity to the functions of three kinds of tactile receptors.

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