This paper deals with a countermeasure by using dynamic absorbers for polygonal wear of work rolls in a hot leveler. First, the authors discuss the optimal design of dynamic absorber mounted on a single degree-of-freedom system where the polygonal wear phenomena are generated. We obtain the characteristic root approximately, and apply the optimal design procedure of dynamic absorber for forced vibration of a single degree-of-freedom system to this self-excited vibration system. As the result, we obtain a design in which the system is stabilized perfectly. Secondly, the result is applied to a hot leveler as a two degree-of-freedom system through the modal analysis. As the result of numerical analysis, the hot leveler is changed into a perfectly stable system by two dynamic absorbers for the first and second vibration modes, and the polygonal wear phenomena are not generated at all.

View full abstract

In order to prevent the pattern formation phenomena caused by the unstable vibration generated in time-delay systems, an optimum design method of dynamic absorber is formulated for contact rotating systems of viscoelastic, grinding and wear types with single-degree-of freedom. In addition, as a key tool for the optimum design, a very efficient and accurate method of stability analysis is newly developed for the pattern formation phenomena generated in contact rotating systems. In the formulation of the optimum design method, the stabilization of the system under the worst conditions is targeted. As a result, the limit of applicability of the dynamic absorber is clarified and it becomes possible to stabilize the system under ordinary conditions by the dynamic absorber without knowing the details of viscoelastic, grinding and wear characteristics of the system.

View full abstract

Efficient aseismic design method of boiler structures is studied focused on joint elements between boiler and its supporting structure, in which passive and semi-active dampers are equipped. Based on substructure synthesis approach, transformation method between dual-mass model/multi-mass model is proposed and the equations which relate the joint element parameters in both models are derived. Based on numerical examination, it was shown that results of dual-mass model parameter survey are reflected accurately to multi-mass model which is used in actual design.

View full abstract

This paper deals with the seismic response simulation of storage tanks, which is coupled with the physical spring mass subsystem and the modal spring mass subsystem. The effect of participation factor is introduced in mass matrix and the unilateral contact model for slip and stick due to the friction force is introduced in the equation of motion. The slip response with shaking table excitation test verified the simulation model presented here. Parametric studies for four kind of actual size tank are conducted to examine the effect of participation factor and the friction force on the seismic response of the tank.

View full abstract

This paper discusses the nonlinear characteristics of the gear coupling derived by tooth contact analysis and the verification test of the analysis method. Tooth contact analysis evaluates the load distribution by solving simultaneous linear inequality derived from compatibility condition of the tooth deformation and balance condition of the force. By applying this method to the gear coupling, we evaluated bending moment and shear force. It was found that nonlinearity of stiffness and damping occurred by the change of contact region of all teeth by load torque or alignment. Rotor dynamics coefficient of the gear coupling was clarified, and it was enabled that the nonlinearity of the gear coupling could be considered for the design of rotating machinery. Next, the tooth stress, bending moment and shear force were measured in the static loading test to verify the analysis method. Analysis results showed the good agreement with the experimental ones, and it was clarified that the analysis method was appropriate.

View full abstract

Numerical and experimental investigation were carried out on transport of particles in an electrostatic traveling field. A three-dimensional hard sphere model of the Distinct Element Method was developed to simulate dynamics of particles. Forces applied to particles in the model were the Coulomb force, the electrostatic force due to polarization of particles in the non-uniform field, the gravity, and the viscous drag. Friction and repulsion between particle-particle and particle-conveyer were included in the model to replace initial conditions after mechanical contact. Two kinds of experiments were performed to confirm the model. One was the measurement of charge of particles that is indispensable to determine the Coulomb force. Charge distribution was measured from locus of free-fallen particles in a parallel electrostatic field. Averaged charges of bulk particles were confirmed by the measurement with a Faraday cage. The other experiment was measurements of bulk and differential dynamics of particles on a conveyer consisting of parallel electrodes to which four-phase traveling electrostatic wave was applied. The calculated results agreed with those measured and the following were clarified : (1) Coulomb force is the most predominant to drive particles. (2) The direction of particle transport did not always coincide with that of the traveling wave but partially changed depending on the frequency of the traveling wave, the particle diameter, and the electric field. (3) Although some particles overtook the traveling wave at the very low frequency, the motion of particles was almost synchronized with the wave at the low frequency. (4) The transport of some particles delayed to the wave at medium frequency and almost all particles were transported backward at high frequency.

View full abstract

This paper describes micro-parts feeding using a saw-tooth surface. In parts feeding, a driving force applied to each part must vary according to the moving direction of the part so that the part moves in one dirction. Traditional feeders employ oblique vibration or asymmetric vibration of a feeder surface, which aften causes unstable motion of micro-parts. In this paper, we propose micro-parts feeding using a sawtooth surface with simple planar and symmetric vibration. First, we describe the principle of the proposed parts feeding. Contact model between a micro-part and a saw-tooth is then analyzed to formulate the condition for the feeding. Next, we show experimental results to examine whether the proposed method performs micro-parts feeding. Finally, we discuss how the feeding model explains experimental results.

View full abstract

The purpose of this study is to make clear the influence of the shape of structure on vibration energy. The vibration energy flow is expressed by structural intensity. In this paper, we use beams with suddenly changed cross section. We performed the numerical analysis and the experiment for the structural intensity of these beams. Then, we investigate the influence of the suddenly changed cross section of beam on the structural intensity. Furthermore to verify the obtained results, we perform an experiment on vibration energy flow of the beam. As a result, it is clarified that the structural intensity is one of the effective parameters for structural health monitoring.

View full abstract

This paper describes an autonomous mobile surveillance system used in a factory premises with some high-rise buildings. This system consists of a wireless LAN network, a base station and an autonomous vehicle. The vehicle is equipped with a GPS/INS navigation system using a Real-Time Kinematic GPS (RTK-GPS), an Area Laser Radar (ALR), a slaved camera, and an Omni-Directional Vision (ODV) sensor for surveillance and reconnaissance. The vehicle switches control modes according to the vehicle navigation error and obstacles on the planned route. It has three guidance modes, which are “Normal”, “Road tracking”, and “Crossing recognition”. A field test reveals that the vehicle can track the planned path within 0.10 [m] accuracy at straight paths and within 0.25 [m] for curved paths even if RTK fixed solutions are not available. Field experiments and analyses have proved that the proposed system can provide sufficient navigation and guidance performance under poor satellite geometry and visibility, and that the panorama image database with absolute position is useful for surveillance.

View full abstract

Switching inductive shunt damping technique is one of the most useful methods for structural vibration control due to its simplicity and robustness. In this paper, a method to design the inductance and the resistance in the shunt circuit is discussed. Initial response and harmonic response are especially considered in the design method. The design method is validated by simulation. Furthermore, switching shunt damping applied for a multi degrees of freedom system is examined using an experimental plate.

View full abstract

This paper is concerned with a new vibration suppression technique utilizing velocity change caused by inelastic collision of masses. It is verified that the proposed method is basically effective to suppress harmonic vibrations. As an application of this vibration suppression principle, a vibration reduction problem of so-called stacker crane system is considered and a novel lift-up strategy of the platform is proposed for reduction of the residual vibration. The effectiveness of the proposed method is demonstrated by experiments using the small-scaled experimental model of the stacker crane.

View full abstract

In ropeway systems, to more increase the safety and reliability of transportation, it is extremely important to do operation control under wind in accuracy since the excessive swing of the carrier by wind may lead to a serious accident such as a collision with the columns. This paper presents (1) results of investigation of wind and carrier swing characteristics in two ropeway installations, (2) simulation results of carrier swing based on wind speed distribution and (3) an estimation method of limit wind speed of operation using carrier response simulation to random wind. Results of estimating limit wind speed of operation in two ropeway installations are reported as well

View full abstract

This paper concerns the minimization of an interior acoustic potenitial energy of a drum-like structure ; a strongly coupled structural/acoustic enclosure. The drum-like structure simulated as an automobile consists of two flexible walls facing to each other-a windscreen and a rear window-and rigid walls. First, optimal feedforward control laws in terms of both the active noise control (ANC) and active vibration control (AVC) for minimizing the acoustic potential energy of the drum-like structure are derived, the fundamental characteristics of the control system being clarified. It is found that the control power radiated by secondary sound sources for ANC as well as that injected by control actuators for AVC becomes null when the acoustic potential energy is minimized. Moreover, a numerical simulation is conducted, showing a theoretically achievable control effect for minimizing the acoustic potential energy together with the affect on the kinetic energy reduction of a rear window.

View full abstract

In this paper we try to realize the active control of shock by an experimental procedure, in which the collision between two objects is controlled so as to make the deformation of one object large and the other small. Two control systems are applied to this experiment. One of them is an LQI control system with Kalman filter and the other is an H_∞ control system. In both systems, we proposed a controller switching at a time when the object deforms from the elastic range to the plastic range. In order to evaluate effectiveness of control, the deformation ratio between the objects is introduced. In our experiment the discretized control system is implemented in a digital signal processor used to realize real-time control. As a result of experiment it was verified that the active control of shock is realizable and the controller we designed is useful for shock control.

View full abstract

Since frontal collision is the dominant form of automobile accidents, there have been many researches on the occupant behavior during the frontal collision. Most of these researches use complicated dynamics models of the multiple degrees of freedom and large-scale FEM. Therefore, it is difficult to make use of them for the initial design because the specifications of body structures and protection devices are not determined in the initial stage. In this paper, a simplified occupant model with small degrees of freedom was introduced, and the spring characteristics of each body joint and the seat belt were identified by experiments with sled testing. As a result, a prediction of the chest deceleration, which is one of the most important performance indexes, and an analysis of the dynamics mechanism at the initial design stage became possible.

View full abstract

The present paper discusses driving/braking force distributions of direct yaw moment control (DYC) to balance tire workloads effectively. The optimum distributions to minimize the maximum workload are derived in the form of simple algebraic expressions. For improvement of vehicle stability and maneuverability, an active four-wheel steering is integrated with DYC by the minimax optimization. The four-wheels are steered by a model following sliding mode controller to maintain zero-sideslip of the vehicle body. Numerical simulations with CarSim, a popular multi-degree-of-freedom vehicle model, are performed to prove effectiveness of the proposed control scheme.

View full abstract

This study proposes an improved method for stabilizing straight running of two-wheeled vehicles. An analysis of the two-wheeled vehicle's vibration modes was completed using the Energy Flow Method, which calculates energy flow of external forces in each motion. Based on these results, we examined the control using steering torque as the control input. Controlling steering torque with rolling acceleration feedback increases wobble and weave mode stabilities. Wobble mode stability is increased by the external force concerning rolling motion. Weave mode stability is also increased by the phase lead of front tire side force in yawing motion. Using another variable as a feedback control signal, for example controlling steering torque with yaw rate feedback, increases only one mode's stability and destabilizes the other mode.

View full abstract

Piezoelectric elements, which are electrically connected to external shunt circuits, are introduced to suppress bending vibration of a scalemodel of a railway vehicle. The authors proposed two types of shunt circuits aiming at practical use. One circuit is equivalent to a inductor and a resistor in series, and the other a negative capacitor and a resistor, and both circuits are designed for use under conditions of large vibration amplitude that causes high voltage of the elements. Results of excitation tests show that the first bending mode of the scalemodel can be suppressed successfully. Moreover, the circuit including the negative capacitor can also reduce vibration associated with higher eigen modes.

View full abstract

To investigated an inadequate track circuit shunting phenomena which rarely causes a serious railway accident, authors stuck bio-electric amplifiers on the wheel sets' axles of an experimental model truck. They operated the truck on an experimental model test track which was setup with a new conception so as to constantly keep the applied voltage to the wheelsets of the truck. Using the bio-electric amplifiers, the shunting circuit resistance of the wheelsets was continuously measured by the minute difference voltage induced in the wheelset. They investigated the relation ship between the running surface of rails and wheels and the shunting resistance. As the results, they found that the surface roughness of the wheel in a minute scale was radically decreased according to the running distance and that the resistance was simultaneously increased.

View full abstract

In this paper, a swing up control scheme for a serial double inverted pendulum system is proposed. The pendulum system is cart-type and the swing upcontrol includes a position control of the cart. The control scheme is to swing up the pendulum in three steps, Step 1 : to swing up the first pendulum. Step 2 : to swing up the second pendulum while stabilizing the first pendulum at the upright position, and Step 3 : to stabilize the two pendulums around the unstable equilibrium state. In each step a control scheme and a switching rule from a step to the next step are given. And the position control of the cart by using feedback stabilization control is included in the controller of each step. For the controller of Step 1, the energy control method based on Lyapunov method is applied to swing up the first pendulum and the feedback stabilization controller of a cart position is added so as to satisfy the condition of Lyapunov method of the first pendulum. For the controller of Step 2, the proposed method combines a stabilization control method of the first pendulum and the cart position using sliding mode control method, and a swing-up control method of the second pendulum using energy control method. And for the controller in Step 3, the sliding mode controller stabilizing both of the pendulums and the cart position is used. A numerical simulation and an experimental result are given to show the effectiveness of the proposed scheme

View full abstract

In this paper, the stabilization problem of a plant with known delay in observation is studied. Although several methods, the Smith predictor or the state predictive control, have already been proposed about the control of plant with time delay, theoretical limitations and the practical inconvenience were left to be solved; e. g., the Smith predictor can only treat the stable systems, and the numerical integration of the exponential function is difficult in the state predictive control. The presented method combines the state feedback control with the delayed feedback control, which can stabilize the unstable systems and can be easily performed. The numerical simulation of the stabilization of the serial double inverted pendulum shows that the proposed method can he applied to stabilization of the unstable system and is effective for the impulsive disturbance.

View full abstract

In this paper, a tuning method of multivariable PID controllers based on partial model matching on frequency domain is proposed. Different from the previous methods which were considered by authors, in this case, determination of multivariable PID controller parameters is defined as a nonlinear optimization problem with inequality constraints. In this procedure, the objective function is constructed so as to minimize the relative frequency model error between the loop transfer function of the control system and that of reference model system at finite frequency points. Inequality constraints are introduced so as to guarantee the stability criteria of multivariable control system given in Rosenbrock's stability theorem. The effectiveness of the method is illustrated through a simulation of 2-input 2-output system.

View full abstract

Reusable launch vehicles (RLV) return to earth by gliding without thrust. In the return phase, one of the most likely and important faults to occur in the airframe is a jamming of an elevon. To tolerate this fault, the flight control system must maintain stability and performance during such a jam. Since this kind of fault can be modeled as a structured parameter deviation from a robust control point of view, this paper uses the μ-synthesis to present new methods to achieve a fault tolerant flight control system. ALFLEX (Automatic Landing FLight EXperiment), the automatic landing experimental vehicle being developed for RLV, is studied as an example. Some simulations are shown to verify the usefulness of the proposed method.

View full abstract

Sliding mode control is a nonlinear control strategy that is well known for its robustness characteristics. However, the discontinuous control signal causes a significant problem of chattering. In this paper, a synergistic combination of neural networks with sliding mode control methodology for magnetic levitation systems is proposed. In the present approach, a neural network is utilized to estimate the equivalent control. Moreover, a new and simple approach is utilized to construct switching control term for overcome the chattering problem. As a result, the chattering is eliminated. The reduction of the chattering of sliding mode control is achieved by using a defined distance function as the switching control term which only measure the distance between the trajectory of state errors and the sliding surface. Experimental study carried out on the magnetic levitation system is presented. Experiments verified that the proposed control has the advantage of less chattering in sliding mode control.

View full abstract

This paper presents a recognition method which can vary the contact area of a tactile sensor with multi artificial whiskers. Previously we have proposed a new tactile sensor which mimics whiskers of animals and established a basic recognition method for the proposed sensor. The previous method distinguishes contact objects by the neural network from the combination of deformations of plural whiskers whose number and arrangement are steady. The change of the number of whiskers needs reconstruction of the neural network and the increase in the number of whisker rises learning time to construct the neural network. Thus, the previous method can recognize only small objects in a limited area. Therefore, the present paper proposes a new recognition method that uses an equivalent whisker composed of plural whiskers. The tactile sensor is composed of plural arranged equivalent whiskers, and contact objects will be recognized by the combination of the deformations of the equivalent whiskers. This paper shows the recognition can be performed by the same neural network if the number of whiskers comprised in the equivalent whisker is varied. Thus the proposed method can recognize contact objects by adjusting the number of the whiskers, thereby the contact area of the tactile sensor will be varied.

View full abstract

The mechanical deformation of a human fingertip when pressing on a flat plate was numerically analyzed using a three-dimensional human fingertip model constructed from CT images of human index finger. The fingertip model was constituted of three parts : a distal phalanx bone, skin/subcutaneous tissue, and a nail. The analyses were carried out at 34 to 200 kPa of seven Young's moduli, and at 0.3 to 0.5 of five Poisson's ratios. The numerical results were compared with the reported experimental data of human fingertip. The numerical results showed that the deformation around the nail and at the distal fingertip was generated subsequently to the large deformation of pulp. The numerical deformation results showed a similar pattern to the experimental data. From the numerical results, we calculated the length of the contact area on lateral view and the width of the contact area on axial view in order to qualitatively estimate the deformation. By comparison of numerical and experimental results, there were no unique values of Young's modulus and Poisson's ratio to express the experimental results. These results suggest that the epidermal, the dermal, and the fat tissue constituting the skin/subcutaneous tissue may influence to the mechanical deformation by these different contributions

View full abstract

Tactile sensation of the human hand was measured using two methods : static two-point discrimination test (s2PD) and moving two-point discrimination test (m2PD). The volar side of the right hand of ten subjects (21-24 year old men) was divided into 29 areas each, according to the location of finger joints and the innervation regions of peripheral and peripheral nerves. The shortest threshold of s2PD was measured in the 2nd distal phalanx, which value was 1.4 mm±0.5 mm, and the shortest threshold of m2PD was also measured in the 2nd distal phalanx, which value was 0.7 mm±0.5 mm. In all 29 areas, the threshold of m2PD was significantly (P<0.01) shorter than that of s2PD. That is, the dynamic stimulus allows generating much response of mechanoreceptive afferent units than the static stimulus. The strong correlation (r=0.95) was found between the threshold of s2PD and that of m2PD on the volar side of human hand.

View full abstract

A vibration-type ultrasonic vibrator works as an ultrasonic motor when it is pressed slantwise against the surface of an object. In our previous paper we made a trail robot hand with three fingers that each works as an ultrasonic motor. This robot hand can simultaneously grasp a cylindrical body and rotate it about its axis. High torque is obtained when an optimum contact force is used for the ultrasonic motor. We propose a detection method to measure the grasping force of the robot hand by the change in the amplitude of vibration. It was confirmed that the vibration amplitude detected by a piezo-element on the vibrator was decreased almost linearly with increase in the grasping force of robot hand. The grasping force affects very little change in the resonance frequency of the vibrator in comparison with the temperature by its self-vibration.

View full abstract

The purpose of this study is to develop a head unit of the earth-propelling hose to carry sensing devices, so that victims under the ground can be found out in a short time. As its first stage, this paper deals with (1) the design concept of the earth-propelling, (2) the comparative examination of the propelling methods to reduce the earth pressure, (3) consideration of the desired shape of a nozzle, and (4) the proposal of the head unit mechanism to steer the direction. And finally the driving experiment in earth is carried out through the developed mechanical model and the validity of the proposed idea is verified.

View full abstract

We discuss the optimum design issue for tracing type legged robots in the sense that it can jump as high as possible. By applying dimensional analysis techniques, we introduce four non-dimensional parameters that control the jump ratio (=h/l) for a tracing type jumping robot. An interesting observation is that there exists the optimum design point where the jump ratio becomes maximum. Through experiments, we found that the robot with the optimum design specification can achieve the jump ratio of 3.6, while the jump ratio decreases for other design points.

View full abstract

In this paper, a hybrid nanorobotic manipulation system is presented. This manipulation system consists of a manipulator being able to work inside a scanning electron microscope (SEM), SEM nanorobotic manipulator, with a small manipulator being able to work inside a transmission electron microscope (TEM), TEM nanorobotic manipulator. The TEM nanorobotic manipulator consists of a 3-degree-of-freedom (DOF) manipulator actuated with 4 piezoelectric stacks and a 3-DOF passively driven translational sample stage. This stage is pre-manipulated with the SEM manipulator for sample preparations inside the SEM. The system enables high resolution manipulation inside the TEM by setting samples inside the SEM. The methodology is named as hybrid nanorobotic manipulation so as to differentiate it from those only with an exchangeable specimen holder. To show the effectiveness of the system, the elastic modulus of a carbon nanotube (CNT) was measured to be 1.23 TPa inside the TEM after being pre-manipulated inside the SEM. With this system, we can measure the inner diameter of a CNT and improve the accuracy in measuring the elastic modulus of a CNT.

View full abstract

For millimeter-sized working micromachines using fluid power with high density, a novel microvalve with simple structure using magneto-rheological (MR) fluid is proposed and called the micro MR valve. The micro MR valve utilizes the apparent viscosity controllability of the MR fluid in the magnetic field. To control sufficiently high magnetic flux density in the microvalve, a magnetic circuit using a permanent magnet, a thermosensitive ferrite, and Peltier elements called the thermocontrol magnetic circuit is introduced. First, the micro MR valve is proposed and the basic characteristics are theoretically investigated. Second, the thermocontrol magnetic circuit is fabricated and the static and dynamic characteristics are experimentally investigated and improved. Finally, a 3-port micro MR valve is fabricated and the characteristics are experimentally clarified and improved.

View full abstract

A new paper separation and feed mechanism is proposed to realize a highly reliable paper handling system for printers. A prototype mechanism consisted of a plate or roller separation electrode coated with an insulated film, a ground electrode, and a paper pile between the electrodes. When high voltage was applied between the electrodes, charge was excited on the insulating film and eletrostatic force is applied to the paper. Electrostatic separation of a sheet of paper was realized at the top of the pile when the applied voltage exceeded a threshold voltage to generate electrostatic force large than the weight of a sheet of paper. The threshold voltage was about some kV, and it agreed with the numerical value obtained by the FEM calculations for the electrostatic field. In the next step the roller electrode was rotated to feed the attached paper. However the applied voltage had to be increased to separate subsequent papers, because charge on the insulated film was cancelled by the attached paper. Then a biased charger roller was settled in contact with the roller electrode to charge the insulating film on the roller separation electrode. In this system, reliable paper separation and feed was realized and a feed speed over 600 mm/s was demonstrated.

View full abstract

The spring constants and damping coefficients of molecularly thin liquid bridges of PFPE lubricant forming between a diamond tip and DLC surface of a magnetic disk are estimated by means of regression analysis of tip damping vibration. Two PFPE lubricants having functional end groups (Zdol 2000 and Zdol 4000) with respective thicknesses of roughly 20 nm and 40 nm, were coated on a DLC disk surface in order to form a liquid bridge between the disk and the probe tip. This tip, with an exceptionally small curvature radius of 0.1 mm, was in separate experiments both retracted from and extended toward the disk surface in a stepwise motion, and the liquid bridge was made to vibrate at each step. By applying regression analysis to observed waveforms, the spring constant and the damping coefficient of the liquid bridge were estimated within an elongation range from 50 to 800 nm. The spring constant, k_m, of the liquid bridge had negative values varying from-0.15 to-0.1 N/m. Damping values expressed in the form of frequency-multiplied damping coefficients, c_m×ω, ranged from 0.02 to 0.06 N/m. It is interesting to note that both |k_m| and c_m×ω decreased with bridge elongation, and after reaching the minimum, those values began to increase.

View full abstract

The friction and wear characteristics of newly developed wear resisting stainless steel, which was designed for improving friction and wear characteristics, were investigated with ring on disk test apparatuses under oil lubricating condition and non-lubricating condition in air and in vacuum. The friction and wear behaviors were compared with those of JIS SUS420J2 stainless steel. In case under non-lubricating condition in air and in vacuum, both friction coefficient at room temperature and wear amount of the wear resisting stainless steel were smaller than those of SUS420J2. The extent of transference of wear debris was comparatively small in case of the wear resisting stainless steel. In case under oil lubricating condition, the scuffing of the wear resisting stainless steel was hard to progress and the wear amount was also small even after scuffing occurrence. The wear resisting stainless steel had the superior anti-scuffing characteristics.

View full abstract

The Oldham coupling transmits a rotary motion with constant velocity between two parallel shafts. This Oldham coupling consists of the three elements; the input shaft, the intermediate element, and the output shaft. The motion of the intermediate element is similar to that of the “hulahoop”. As a result, the input torque cyclically changes under the constant output torque. First the motion of the intermediate element of the Oldham coupling is analyzed. An instantaneous center of rotation of the intermediate element is found. The fixed centrode is obtained as the locus of this center in the fixed coordinate system. The moving centrode is also obtained as the locus of this center in the moving coordinate system attached on the intermediate element. Input torque is obtained by analysis and statics. Secondly, the Oldham coupling is designed and made. Input torque is measured compared with theoretical one. Thus the motion of Oldham coupling is verified theoretically and experimentally.

View full abstract

Recently, some activities for environmental protect have been tried to reduce environmental burdens in a lot of fields. Manufacturing field is also required to reduce them. Hence, prediction system of environmental burden for machining operation is proposed based on LCA (Life Cycle Assessment) policy for future manufacturing system in this research. This system can calculate environmental burden (equivalent CO₂ emission) due to electric consumption of a machine tool, cutting tools, coolant, lubricant oil, metal chips and provide the information of accurate environmental burden of machining process by considering some activities related to machine tool. In this paper, the development status of prediction system is described. As a case study, two NC programs that manufacture simple shape are also evaluated to show the feasibility of it.

View full abstract

The tensile strength of the composite material from bagasse fiber (remains after sugar cane squeezed) and biodegradable resin was investigated in view of the content of bagasse fiber, and validated by short fiber strengthen theory with Monte Carlo method. The result is as followings. The tensile strength increased with increasing the content of bagasse fiber. Micrograph observation showed the bagasse fiber, which has a honeycomb structure in the cross section, was compressed in press forming. The compressed bagasse fiber contributed to increase the tensile strength. This expectation was validated through the simulation with Monte Carlo method based on short fiber strengthen theory which takes the compression ratio of bagasse fiber into consideration. The simulation result showed that the tensile strength of the composite material and its variation make a good correlation with the experimental result.

View full abstract