A method of analysis is presented for determining the free vibration frequencies and mode shapes of open paraboloidal shells of revolution having arbitrary thickness. Unlike conventional shell theories, which are mathematically two-dimensional (2-D), the present method is based upon the 3-D dynamic equations of elasticity. The ends of the shell, as well as the inner and outer curved surfaces, may be free or may be subjected to any degree of constraint. The strain energy of deformation, as well as the kinetic energy of motion, are formulated in terms of three displacement components which are tangent or normal to the shell middle surface. The displacements are taken as periodic in the circumferential coordinate and in time, and as polynomials of arbitrary degree in the other two coordinates, and the Ritz method is used to formulate the eigenvalue problem. Convergence studies are presented, and frequencies are given for moderately thick and thick, moderately deep and deep, paraboloidal shells of uniform and variable thickness.

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Deep paraboloidal shells of revolution are common components for horns, nozzles, rocket fairings, etc. This study is to investigate the micro-control actions and distributed control effectiveness of precision deep paraboloidal shells laminated with segmented actuator patches. Mathematical models and governing equations of the paraboloidal shells laminated with distributed actuator layers segmented into patches are presented first, followed by formulations of distributed control forces and micro-control actions including meridional/circumferential membrane and bending control components based on an assumed mode shape function and the Taylor series expansion. Distributed control forces, patch sizes, actuator locations, micro-control actions, and normalized control authorities of a deep paraboloidal shell are analyzed in a case study. Analysis indicates that 1) the control forces and membrane/bending components are mode and location dependent, 2) the meridional/circumferential membrane control actions dominate the overall control effect, 3) there are optimal actuator locations resulting in the maximal control effects at the minimal control cost for each natural mode.

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Dynamic characteristics of cylindrical composite panels with co-cured and constrained viscoelastic layers are investigated using the finite element method based on the layerwise shell theory. The natural frequencies, loss factors and frequency response functions of cylindrical viscoelastic composites are computed considering the effect of transversely shear deformation and material degradation of viscoelastic layers. Various damping characteristics for unconstrained layer damping, constrained layer damping, and symmetrically co-cured laminates are compared with an original base panel in view of damping efficiency. The layerwise in-plane displacements and shear deformations greatly influence vibration and damping characteristics of the hybrid composite panels. Also, the present results show that it is very important to consider the variation of damping properties according to exciting frequency and environmental temperature for the accurate damping evaluation of cylindrical hybrid composite panels with viscoelastic damping layers.

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An inverse analysis method has already been proposed by one of the authors to identify elastic parameters of laminated composite materials using the FEM eigenvalue analysis. The purpose of this study is to apply the proposed method to a laminated circular cylindrical shell and to compare the estimated elastic parameters of the lamina with the obtained experimental ones. First, by applying the experimental modal analysis technique to a laminated circular cylindrical shell with free boundary conditions, natural frequencies and mode shapes are obtained. Next, by considering the obtained natural frequencies and mode shapes, the elastic parameters for the lamina of the shell are identified. On the other hand, the elastic parameters of the lamina are obtained experimentally. These experimental elastic parameters were compared, and found to agree well, with the elastic parameters identified using the proposed method.

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In this report, refined analytical method is proposed for calculation of natural frequencies of laminated composite cylindrical shells. Proposed computational model is based on the method which estimate rotation of transverse cross section and the curvature of middle-plane of laminated shells introducing equivalent transverse shear stiffness and equivalent curvature. The method includes transverse shear deformation and material anisotropy of composite materials. Natural frequencies calculated in numerical examples for graphite/epoxy cross-ply laminated composite cylindrical shells simply supported at both ends are compared with the solutions by the first-order shear deformation theory (FSDT) and classical shell theory (CST). Results obtained by the present method are in good agreement with results by FSDT as about several percent errors for in spite of thick and shorter cylindrical shells.

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The superposition method is employed to obtain an analytical type solution for the free vibration of cable supported bridge decks. Each pair of vertical elastic cables is considered to impart a vertical force to the deck by means of a rigid cross-member passing transversely beneath it. Rigid knife-edge support encountered at bridge towers is handled as well. In this introductory study the deck is treated as a thin isotropic plate. Any number of support cable pairs, of any stiffness, may be handled. Inter cross-member distances are referred to as spans. Free vibration eigenvalues and mode shapes are presented for three and four span illustrative cases.

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A refined solution procedure is presented for analyzing out-plane free vibrations of a rotating circular plate. The equations of motion and boundary conditions are derived by considering the effect of initial tensions due to the rotation. The equations of motion are solved exactly by power series expansions. Based on the numerical calculations, some interesting results, such as in-plane stress distributions in steady rotation, frequencies and mode shapes of the circular plate in out-plane vibration, are presented. The results of the present and classical theory are compared, which verify the advantages of the proposed theory.

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Noncontact vibration control of a magnetic levitated rectangular thin steel plate was studied experimentally. We fabricated equipment which enables the generation of elastic vibration via forced input of disturbance to a levitated thin steel plate, so that the suppressive effect on the elastic vibration could be examined. Two models of the steel plate, a single-degree-of-freedom model and a continuous model, were considered in this study. By applying the optimal control theory to the each model, the superiority of the models with respect to the suppressive effect of elastic vibration was examined. Furthermore, suboptimal control was applied in which spillover of elastic vibration was considered, the experimental results obtained using the optimal control and the suboptimal control were compared, and the applicability of these controllers was discussed.

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Recently, tracked vehicles are being equipped with a rubber crawler and they are used for leisure vehicles, snow machines, etc. With these applications, the resonance problems are common knowledge. The vibration characteristics of crawlers are experimentally examined. They have some resonance points caused by the differences in thickness of the crawler. These vibrations will make some noise and possibly cause system destruction. In order to analyze these vibrations, an approximate analytical model, which is based on the linear wave equation, including an effect of crawler velocity is introduced. Vibration characteristics are compared with exact solution and the experimental result. In order to suppress the resonance vibration, a bang-bang control method, which is part of the variable structure system control, is adopted. We experimentally and theoretically examined vibration and control of the crawler. As a result, that control method provides us the possibility of vibration suppression for the actual tracked vehicles.

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This paper presents a procedure to derive reduced-order nonlinear modal equations of plates using mode vectors obtained by the finite element method. Nonlinear finite element formulation is derived by the principle of virtual work taking into account geometrical nonlinearity. Modal analysis is applied to the nonlinear finite element equation by using mode vectors obtained by finite element analysis. Reduced-order modal equations are derived by using modal coordinates of several dominant modes and neglecting in-plane inertia. Nonlinear modal equations of rectangular plates are derived, and numerical results for the fundamental out-of-plane mode and an internal resonance show good agreement with those presented in other papers.

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In many mechanical structures, structural design for noise reduction is becoming increasingly important. Noise reduction is often achieved through structural modifications. However, it is hard to predict the effectiveness of noise reduction by typical approaches. This paper presents an optimal design approach for reducing sound power from a vibrating plate by its curvature design. The method couples an optimization technique based on a genetic algorithm (GA) with the shape representation technique, vibration analysis and acoustic radiation analysis. It is shown that the curvature design of the plate obtained by using this method can achieve effective reductions in radiated sound power. Finally, the robustness of the optimized design candidates obtained is studied by using stochastic simulations in order to find those candidates which are least sensitive to changing design parameters.

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This paper presents an optimal design of a flexible structure reinforced by fiber-reinforced plastic (FRP) sheets that takes into account both stiffness and damping characteristics. An FRP sheet has a high ratio of strength to weight and is used to reinforce various structures. Vibration characteristics of a structure reinforced by FRP sheets can be easily modified by changing design variables such as the relative volumes of fibers and matrix, the fiber angle and the number of layers. We propose an objective function that takes into account both stiffness and damping characteristics. To improve vibration characteristics, the design variables were determined by using an optimization technique. Vibration characteristics of the optimized structure are superior to those of a structure whose natural frequencies are maximized, because the damping characteristics of the optimized structure are improved as well as the stiffness. The validity of the present method is verified by numerical examples and by comparison with results of experiments.

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This paper studies the assumption of displacements employed in the vibration analysis of laminated composite plates. For this purpose, the maximum strain and kinetic energies of a cross-ply laminated plate are evaluated analytically based on the three-dimensional theory of elasticity. The displacements of the simply-supported rectangular plates are expanded into the polynomial forms with respect to a thickness coordinate, and then governing equations are formulated by using the Ritz's method. In the numerical calculations, natural frequencies and modal damping ratios are calculated for the plates with different stacking sequence and the thickness ratios. The validity of the assumption of displacements and the applicability of the other plate theories (e. g. Classical Lamination Theory, First-order Shear Deformation Theory and Higher-order Shear Deformation Theory) to the laminated thick plates are discussed by comparing the numerical results obtained by the present method with the CLT and the FSDT solutions.

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This work presents an analytical approach and accurate numerical results for the free vibration of symmetrically laminated, thick composite circular and elliptical plates. The shear deformation through the thickness is considered by employing the first-order shear deformation theory. The problem is solved by the Ritz method and the natural frequencies are calculated for three-layered, simply supported and clamped plates with stacking sequence [θ/−θ/θ]. Particularly, extensive results are presented by using various shear correction factors for a wide range of geometric parameters, and the effects of varying the factor upon the free vibration frequencies of the laminated circular and elliptical plates are discussed.

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The subject of structure defect diagnosis has been extensively investigated in the field of nondestructive testing (NDT). In this paper, a new approach for detecting structure damage is proposed, which is based on the combination of the bispectrum feature extraction method and the learning vector quantization (LVQ) identification method. Because bispectrum analysis possesses the capability of restraining Gaussian noise, it may be employed to enhance the performance of the feature extraction method. In simulation, by using the proposed method, it has been shown that very high accuracy of structure damage identification can be obtained compared with the modal assurance criterion (MAC) formed from the modal parameters method, especially in the case of low signal-to-noise ratio environment.

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This paper presents both simulation and experimental investigations into the simultaneous design of a steering wheel and its control system for vibration suppression. The research consists of two steps. In the first step, the simultaneous optimization is formulated as a general nonlinear programming problem with the closed-loop H_∞ norm as objective function. Then the problem is solved by an iterative approach in which the control designs are nested into the structural designs. The simulation results show that the simultaneously optimized system gives much better performance than the original one. In the second step, experiments are performed to verify the effectiveness of the new design method. To deal with the effects of modeling error and system uncertainty, in the experiments µ synthesis is used instead of H_∞ control. It is found from the experimental results that the optimized structure is still superior to the original one after the redesign of control.

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In this paper, an effective method for the nonlinear vibration analysis of rotor systems is proposed using the Component Mode Synthesis method and the harmonic balance method. In the method, the system is divided into components and the differential equations for each frequency and component is derived. The equation of motion for the whole system, then, is obtained using the Component Mode Synthesis method. The dynamic analysis of a rotor system is carried out using the harmonic balance method. The distinguishing feature of the proposed method is that the nonlinear restoring force term is expressed using modal coordinate system in a convenient form. The order of the modal equation of motion and calculation time, therefore, can be reduced. In the numerical example, it is shown that the analysis method proposed in this paper is effective for the nonlinear vibration analysis of rotor systems.

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In this study, we focus on the error in the estimated frequency of disturbance and present a new method of adaptive multiple frequency tracking and a new modification law after examining the relationship between the frequency error and output level in detail. We also develop a multiple frequency estimation algorithm which is insensitive to observation noise and theoretically prove the asymptotic stability for an adaptive nonlinear algorithm and adaptive frequency tracking method. The results of simulation show that when the frequency estimated by the difference equation method approaches the true value, the output error asymptotically converges to zero (or an equilibrium point). This corresponds to the asymptotic stability condition. The effectiveness of this method and the theoretical proof are verified by simulation. The experimental results show that the proposed algorithm is effective for achieving unbalanced vibration suppression.

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We discuss bending and torsional vibration control of a 6-story flexible structure. In the case in which the vibration control of high-rise buildings is considered, it is necessary to design a controller which shows good control performances, and which is simply designed so that personnel expenses are reduced. To this end, we have applied a sliding mode control theory, which is one of nonlinear robust control theories. By adopting this theory, the control system may easily be designed in a very short time. However, since it is in few cases that each story is provided with a sensor, this controller is generally designed as a state feedback controller, and is difficult to realize a state feedback. Therefore, the sliding mode controller should be designed as an output feedback controller. Accordingly, we have designed two output feedback sliding mode controllers by using minimum error excitation method. The first controller is constructed with only nonlinear control inputs, and the second controller is constructed with both linear and nonlinear inputs. We have investigated their performances by numerical simulations and experiments. In this paper, design methods, control system design constraints, and characteristics in flexible structural control will be explained.

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In this paper, modified truck designs were studied with an objective to achieving better compatibility between high speed stability and curving behaviour compared to the conventional truck. The analysis has shown that USD truck can be designed to achieve better over all performance compared to other truck designs. The results of steady state curving program were validated using the commercial software package NUCARS. The comparison of steady state curving behaviour of different truck designs using NUCARS also showed that USD truck has the potential to achieve superior performance compared to other truck designs. The research reported in this paper has dealt with steady state curving behaviour. To look into the safety implications of the new designs, transient behaviour in curves must be studied. The response of the railway cars in entry and exit spirals should be evaluated. The effects of track irregularities on the response of these modified designs need to be analyzed.

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The development of experimental facilities for rail vehicle testing is being complemented by analytic studies. The purpose of this effort has been to gain insight into the dynamics of rail vehicles in order to guide development of the Roller Rigs and to establish an analytic framework for the design and interpretation of tests to be conducted on Roller Rigs. The work described here represents initial efforts towards meeting these objectives. Generic linear models were developed of a freight car (with a characteristic North American three-piece truck) on tangent track. The models were developed using the generalized multi body dynamics software MEDYNA. Predictions were made of the theoretical linear model hunting (lateral stability) characteristics of the freight car, i. e., the critical speeds and frequencies, for five different configurations: (a) freight car on track, (b) the freight car's front truck on the roller stand and its rear truck on track, (c) freight car on the roller rig, (d) a single truck on track, and (e) single truck on the roller stand. These were compared with the Association of American Railroads' field test data for an 80-ton hopper car equipped with A-3 ride control trucks. Agreement was reached among all the analytical models, with all models indicating a range of hunting speeds of 2% from the highest to lowest. The largest discrepancy, approximately 6%, was indicated between the models and the field test data. Parametric study results using linear model of freight truck on the roller rig show that (a) increasing roller radius increases critical speed (b) increasing the wheel initial cone angle will decrease the hunting speed (c) increasing the roller cant increases hunting speed (d) decrowning of the wheelset on the rollers will not effect the hunting speed but induces longitudinal destabilizing horizontal forces at the contact and (e) lozenging of wheelset on the rollers induces a yaw moment and the hunting speed decreases with increasing wheelset yaw angle.

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Conventional railway vehicle systems exhibit hunting phenomenon which increases component wear and imposes operating speed limits. There is also a conflict between dynamic stability and the ability of the vehicle to steer around curves. Alternatively, independently rotating wheels (IRW) in a wheelset eliminate hunting but the wheelset guidance set capability is lost. A compromise solution is made possible by a modified design that exploits a lack of fore-and-aft symmetry in the suspension design. A comparative study on steady state curving performance and dynamic stability of some unconventional truck designs is carried out. The effects of suspension and conicity are considered to evaluate the trade-off between dynamic stability and curving performance.

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In this paper, a robust model following control law based on hyperstability theory will be derived for uncertain systems with input nonlinearities. Under the upper bound assumption for system uncertainties, it is proved that the stability of the proposed control system is insensitive to system parameter variations, unmodelled dynamical errors, and external disturbances by mathematical analyses. It also ensures that the system output can track the desired model output asymptotically and all signals in the proposed control scheme are bounded. Furthermore, some computer simulation results will be presented to illustrate the performance of the proposed robust model following control scheme.

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A robust nonlinear H₂/H_∞ control method is presented for a parallel inverted pendulum system with uncertain parameters and dry friction. The dry friction is quasi-linearized into a describing function model by the random input describing function technique, and the uncertain system under consideration is described by state equations that depend on time invariant, unknown-but-bounded, uncertain parameters. Then, the robust nonlinear H₂/H_∞ control system that establishes the stability of the closed loop system in face of the nonlinear dry friction and uncertain parameters was constructed. However, it is difficult to solve coupled Riccati equations due to the nonlinear correction term contained in the Riccati equations. Thus, it is shown that the Riccati equations can be solved by some algebraic transformations of the coupled Riccati equations. This result enables robust nonlinear controllers to be designed easily. Hence, if the parameters of the parallel inverted pendulum vary as certain bounds, the proposed control has the robustness to both the system parameter variations and the nonlinear dry friction.

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In the analysis of constrained multibody systems, the constraint reaction forces are normally expressed in terms of the constraint equations and a vector of Lagrange multipliers. Because it fails to incorporate conservation of momentum, the Lagrange multiplier method is deficient when the constraint Jacobian matrix is singular. This paper presents an improved dynamic formulation for the constrained multibody system. In our formulation, the kinematic constraints are still formulated in terms of the joint constraint reaction forces and moments; however, the formulations are based on a second-order Taylor expansion so as to incorporate the rigid body velocities. Conservation of momentum is included explicitly in this method; hence the problems caused by kinematic singularities can be avoided. In addition, the dynamic formulation is general and applicable to most dynamic analyses. Finally the 3-leg Stewart platform is used for the example of analysis.

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A novel global sliding-mode control (GSMC) scheme with adjustable robustness is presented in this article. The proposed scheme offers a switching function together with unperturbed system dynamics to weigh the contribution from SMC such that all of the closed-loop poles can be located within predefined regions to provide design flexibility, and the robustness of system can thus be adjusted. By this scheme, the maximal control effort and chattering level can be reduced according to designer's specifications directly. Since the switching function can initially be made to equal to zero, the adjustable performance during the entire response can be guaranteed, and the reaching condition is thus lifted. The efficacy of this scheme is demonstrated via successful implementation on a linear variable reluctance motor (LVRM) servo system. Both simulation and experimental studies further demonstrate its feasibility and effectiveness.

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The optimal tracking design and its corresponding digital redesign for sampled-data systems with input time delay under state and control-input constraints have been proposed in this paper. The multi-objective evolutionary programming (MOEP) is utilized for achieving the desired goals, and the inter-sampling behavior of the designed sampled-data system via the suboptimal digital redesign approach is also considered. To satisfy the pre-specified state and control-input constraints, the MOEP is employed for dynamically tuning the LQ-tracker and the sampling period.

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Results of theoretical investigations on stability characteristics of an actively controlled hydrodynamic journal bearing are presented. The proportional and derivative controls including coupled motion are adopted for the control algorithm to control the hydrodynamic journal bearing with a circumferentially groove. Also, the cavitation algorithm implementing the Jakobsson-Floberg-Olsson boundary condition is adopted to predict cavitation regions in the fluid film more accurately than a conventional analysis with the Reynolds condition. The stability characteristics are investigated with the Routh-Hurwitz criteria using the linear dynamic coefficients which are obtained from the perturbation method. The stability characteristics of the rotorbearing system supported by active controlled hydrodynamic journal bearing are investigated for various control gain. It is found that the speed at onset of the instability is increased for both proportional and derivative control of the bearing, and the proportional and derivative control of coupled motion is more effective than proportional and derivative control of uncoupled motion.

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In the brake systems, it is important to reduce the rear brake pressure in order to secure the safety of the vehicle in braking. So, there was some research that reduced and controlled the rear brake pressure exactly like a L. S. P. V and a E. L. S. P. V. However, the previous research has some weaknesses: the L. S. P. V is a mechanical system and its brake efficiency is lower than the efficiency of E. L. S. P. V. But, the cost of E. L. S. P. V is very higher so its application to the vehicle is very difficult. Additionally, when a fail appears in the circuit which controls the valves, the fail results in some wrong operation of the valves. But, the previous researchers didn't take the effect of fail into account. Hence, the efficiency of them is low and the safety of the vehicle is not confirmed. So, in this paper we develop a new economical pressure modulator that exactly controls brake pressure and confirms the safety of the vehicle in any case using a direct adaptive fuzzy controller.

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A tolerance allocation scheme for automotive body assembly must consider both product tolerance requirements and manufacturing capabilities. The design/functional requirements are considered to be the dimensional requirements of the product, and the manufacturing capabilities are considered to be the tolerance allocated. However, customer demand for quality requires tight tolerance, which current sheet metal manufacturing cannot deliver. Thus, a high product cost is incurred to satisfy customers' high requirements in relation to sheet metal products. In this paper, a generic finite element tolerancing methodology is developed for sheet metal assembly. This methodology is capable of determining the maximum allowable manufacturing tolerance for components before assembly, which satisfies the product requirement as a whole. This method enables a tolerancing scheme to be used in state of the art automotive body panel design.

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We have been developing a casting manipulator which includes a flexible string in the link mechanism in order to enlarge workspace of the manipulator. We proposed the swing motion control as the first step of casting manipulation. In this paper we deal with swing motion and throwing motion of casting manipulation. First, we show a method of generating pendulum swing and demonstrate the effectiveness of the proposed control method through experiments using a prototype casting manipulator. Next, we clarify that the main factors which disturb throwing motion are the time delay of releasing a gripper and frictional force which also disturbs flying motion of the gripper based on the results of throwing experiments. We propose a method of compensating these factors. Through the evaluation by comparing the results of numerical simulation with those of experiments, we show that the proposed method helps to reduce the position error of the gripper which reaches to the target.

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This paper deals with an autonomous behavior-mode switching in a behavior-based learning of a mobile-robotic system, which is composed of two mobile robotic modules consisting of a crawler and one DOF arm. The task is to carry a long bar horizontally along a compound road with keeping the bar-support length constant. We propose an on-line learning method “STL (S-Temperature based on-line Learning)”. During the learning process, the robotic system can build up the state categorization in terms of two-dimensional sensory data (support length and support inclination). The robotic system can transit seamlessly between the learning behavior and the task-achieving behavior according to the internal state of the robotic system that is represented by S-temperature introduced into the STL algorithms. We show the effectiveness of STL algorithm by hardware experiment and the learning characteristics with respect to important learning parameters by computer simulation experiment.

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This paper presents an integration of fuzzy local planner and modified Elman neural networks (MENN) approximation-based computed-torque controller for motion control of autonomous manipulators in dynamic and partially known environments containing moving obstacles. The navigation is based on fuzzy technique for the idea of artificial potential fields (APF) using analytic harmonic functions. Unlike fuzzy technique, the development of APF is computationally intensive operation. The MENN controller can deal with unmodeled bounded disturbances and/or unstructured unmodeled dynamics of the robot arm. The MENN weights are tuned on-line, with no off-line learning phase required. The stability of the closed-loop system is guaranteed by the Lyapunov theory. The purpose of the controller, which is designed as a Neuro-fuzzy controller, is to generate the commands for the servo-systems of the robot so it may choose its way to its goal autonomously, while reacting in real-time to unexpected events. The proposed scheme has been successfully tested. The controller also demonstrates remarkable performance in adaptation to changes in manipulator dynamics. Sensor-based motion control is an essential feature for dealing with model uncertainties and unexpected obstacles in real-time world systems.

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This study deals with a method to realize automatic contour extraction of facial features such as eyebrows, eyes and mouth for the time-wise frontal face with various facial expressions. Because Snakes which is one of the most famous methods used to extract contours, has several disadvantages, we propose a new method to overcome these issues. We define the elastic contour model in order to hold the contour shape and then determine the elastic energy acquired by the amount of modification of the elastic contour model. Also we utilize the image energy obtained by brightness differences of the control points on the elastic contour model. Applying the dynamic programming method, we determine the contour position where the total value of the elastic energy and the image energy becomes minimum. Employing 1/30s time-wise facial frontal images changing from neutral to one of six typical facial expressions obtained from 20 subjects, we have estimated our method and find it enables high accuracy automatic contour extraction of facial features.

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This paper proposes a new passive compliant center device, the Multiple Remote Center Compliance (MRCC), for assembly tasks. The MRCC introduces a new azimuthal compliance over traditional passive compliance mechanisms that can effectively compensate the peg's orientation deviation for polygonal insertions. Besides, a special feature of the adjustable compliance provides capability to overcome the gravity effect. Non-vertical insertions therefore become possible. A spring-supported object in space is also adopted for stability analysis of this compliant device. Actual experimental assembly processes demonstrate promising results on polygonal insertions in both traditional top-down and horizontal directions.

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A numerical procedure for non-steady 3-dimensional elastohydrodynamic lubrication analysis was applied on the cam-roller contact of the valve mechanism for a marine diesel engine. Both the pressure distribution and the film thickness between the cam and roller follower acting dynamic load were calculated for each time-step of the whole rotation cycle. A new profiling method for roller edge was suggested using the results of elastohydrodynamic lubrication analysis. The analysis results of the new profile roller were compared with those of the conventional dub-off profile roller. The peak pressure at the roller edge was removed completely with the new profile.

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A dynamic routing method for automated guided vehicles that run on a bi-directional guide path network is suggested. This is an extension of previous dispatching methods that are called “semi-dynamic routing.” In the previous methods, although current traffic status is considered for finding the conflict-free fastest route, it is assumed that active schedules of previously planned vehicles cannot be altered when a schedule for a new vehicle is introduced. In the full-dynamic routing method of this study, it is assumed that the schedules of previously planned vehicles can be altered by introducing the schedule of a new vehicle. In order to evaluate the performance of the proposed algorithm, computational experiments are performed. The results showed that the proposed algorithm reduces the average travel time of vehicles and improves the throughput of a manufacturing system.

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In recent years, financial difficulties led engineers to look for not only the efficiency of the function of a product but also the cost of its development. In order to reduce the time for the development, engineers in each disciplinary have to develop and improve their objectives collaboratively. Sometimes, they have to cooperate with those who have no knowledge at all for their own disciplinary. Collaborative designs have been studied to solve these kinds of the problems, but most of them need some sorts of negotiation between disciplines and assumed that the negotiation will be done successfully. However, in the most cases of real designs, manager of each disciplinary does not want to give up his or her own objectives to stress on the other objectives. In order to carry out these negotiation smoothly, we need some sort of evaluation criteria which will show efficiency of the product considering the designs made up by each division and if possible, considering the products of the competitive company. In this study, we use Data Envelopment Analysis (DEA) to calculate the efficiency of the design and showed every decision maker the directions of the development of the design. We newly called these kinds of systems as supervisor systems and implemented these systems in computer networks that every decision makers can use conveniently. Through simple numerical examples, we showed the effectiveness of the proposed method.

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We have developed a tactile display that is attached to a user's fingertip. The display presents the touch status between the user's finger and a virtual spatial object by means of a vibratory stimulus. The display is equipped with ten vibratory pins, that are in contact with the surface of an index fingertip or of a thumb. By changing the pattern of vibration, the display presents the geometrical features of an object's surface such as a vertex, an edge, and a plane. An experiment was performed to confirm the user's ability to discriminate among the patterns. A pick-and-place model task in a virtual space was also performed to reveal the effectiveness of the tactile presentation during virtual object manipulation. The results showed that the tactile presentation improved the task completion time and the positional accuracy of the manipulated object.

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A frequency-domain method for estimating the mass, stiffness and damping matrices of a structure is presented. The method is developed based on the normal frequency response functions extracted from the complex ones. In this method, a transformation matrix is obtained first from the complex frequency response functions of a structure. The damping matrix is calculated independently from this transformation matrix, while the mass and stiffness matrices are identified from the extracted normal frequency response functions by using the least squares method. Furthermore, in this paper, it is emphasized that the accuracy of identified system matrices for different data point configurations are addressed. The simulated and experimental results indicate that a more accurate damping matrix can be identified and the present method is insensitive to the data point configurations used in the identification procedure even for cases with only few data points.

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The backward tracing scheme by using the rigid-plastic finite element algorithm is proved here for the first time in three-dimensional deformation by a series of experiments. The backward tracing scheme of the finite element analysis, which is counted to be useful for process design in metal forming, has been developed and applied successfully in industry to several metal forming processes. Here the backward tracing scheme is implemented for process design of three dimensional plastic deformation in metal forming, and it is applied to a precision coining process. The contact problem between the die and workpiece has been treated carefully during backward tracing simulation in three dimensional deformation. The results confirm that the application of the developed program implemented with backward tracing scheme of the rigid plastic finite element leads to a reasonable initial piercing hole configuration. It is concluded that a three dimensional extension of the scheme might be useful for industrial applications.

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This paper describes folding methods of thin flat sheets as well as cylindrical shells by modelling folding patterns through Japanese traditional Origami technique. New folding patterns have been devised in thin flat squared or circular membrane by modifying so called Miura-Ori in Japan (one node with 4 folding lines). Some folding patterns in cylindrical shells have newly been developed including spiral configurations. Devised foldable cylindrical shells were made by using polymer sheets, and it has been assured that they can be folded quite well. The devised models will make it possible to construct foldable/deployable space structures as well as to manufacture foldable industrial products and living goods, e. g., bottles for soft drinks.

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Conical involute gears used for marine transmissions are mostly helical ones. These gears are available in the form of not only intersecting axis gears but also nonintersecting-nonparallel axis gears. The contact between tooth surfaces of a pair of gears is the point contact. Tooth surface durability is generally low. In order to overcome this weak point, one of the authors invented a new type of conical gear called “Concave conical gear”. Concave conical gear has higher tooth durability than the conventional conical involute gear. In this paper, a method to generate the helical Concave conical gear is newly developed. First, the principle of the generating method is introduced, and the tooth surface is analyzed theoretically. Second, test gears are ground. Tooth surfaces of the test gears are measured and compared with theoretical ones, and good agreement is observed.

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This paper is to synthesize the double safety shoes mechanisms of elevators for prompting passenger's safety. A systematic design methodology including type synthesis and mechanism skeletons technology is also presented based on the design requirements and design constraints. The design requirements include to avoiding from collision between shoes, and shoe can be pulled out independently not to drag the door. The design constraints are proposed for assigning link types and kinematic relations. An existing mechanism, which is designed with six links and seven joints, is investigated by mechanism kinematics and structure sketch to establish the topological structure. According to the creative method, all of the possible kinematic chains with the numbers of the vertices and edges are enumerated. Then the linkage numbers are assigned skillfully to the edges, and one of the kinematic pairs, for example, revolute pair, prismatic pair, and rolling pair, is chosen for every vertices. So every kinematic chain can be stretched out several particularized chains. Several mechanism skeletons are also sketched.

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