Showing papers in "Transactions of the Japan Society of Mechanical Engineers. C in 1999"
TL;DR: Control properties exerted at the wrist joint of human upper extremity were analyzed in terms of control engineering as well as electromyographic (EMG) kinesiology to contribute to the position/force control and the stiffness control at the endpoint of the extremity.
Abstract: Control properties exerted at the wrist joint of human upper extremity were analyzed in terms of control engineering as well as electromyographic (EMG) kinesiology. Analyses were performed on the antagonistic pairs of the mono-articular shoulder and elbow muscles and the antagonistic pairs of bi-articular muscles, under the isometric condition with the submaximal as well as maximal efforts. Activity muscular pattern with the maximal effort showed a tightly coordinating activity pattern among the three pair of antagonistic muscles. Under the submaximal force levels, the tight coordination pattern getting loose and showed widely varied patterns. Some loose coordination patterns could control only limited range of output force directions. The existence of coordination control among the three pair of antagonistic muscles contributed to the position/force control and the stiffness control at the endpoint of the extremity.
22 citations
TL;DR: In this article, a columnar feeler and 2-by-2 conical feelers are used to estimate the three-axis force from the area-sum and area-difference of the feelers' contact areas by taking into account wrench-length shrinkage caused by a vertical force.
Abstract: This paper describes precision enhancement of an optical three-axis tactile sensor capable of detecting both normal force and tangential force. The sensor's single cell consists of a columnar feeler and 2-by-2 conical feelers. We have derived equations to precisely estimate the three-axis force from the area-sum and area-difference of the conical feelers' contact areas by taking into account wrench-length shrinkage caused by a vertical force. To evaluate the equations and determine constants included in the equations, we performed a series of calibration experiments using a manipulator-mounted tactile sensor and a combined load-testing machine. Subsequently. to evaluate the tactile sensor's practicality. it was mounted on the end of a robotic manipulator which rubbed flat specimens such as brass plates with step-heights of δe0.05, 0.1, 0.2 mm and a brass plate with no step-height. We showed from the experimental data that the optical three-axis tactile sensor can detect not only the step-heights but also the distribution of the coefficient of friction, and that the sensor can detect fine plate inclination with accuracy to about ±0.4°.
22 citations
17 citations
TL;DR: In this paper, self excited oscillations of the structure coupled with inner fluid occurred in the insulation wail cooling system of fast breeder reactor Super-Phenix-1 (SPX-1) in France during test operations.
Abstract: This paper deals with self excited oscillations of the structure coupled with inner fluid occurred in the insulation wail cooling system of fast breeder reactor Super-Phenix-1 (SPX-1) in France during test operations. We analyzed and performed experiments on the instability of multiple cylindrical structure system which has dual flexible weir shells. We measured self excited oscillations changing various parameters such as discharge flow rate, gap of the liquid height between feeding and restitution plenums. In the experiment, it was found out that dual cylindrical shells oscillate in the inverse phase each other with an oval vibration mode under the specific conditions. Comparison between theoretically and experimentally obtained instability region was made, which shows good agreement.
17 citations
16 citations
TL;DR: In this paper, an integrated control system that consists of an active control of vehicle suspension and a steering system in cornering on curved and randomly uneven roads is analyzed by means of LQR control theory under a preview driver control.
Abstract: Stability of the integrated control system that consists of an active control of vehicle suspension and a steering system in cornering on curved and randomly uneven roads is analyzed by means of LQR control theory under a preview driver control. It is confirmed that maneuverablity is much improved for safer cornering along a desired curve on uneven roads. The simultaneous optimization of design parameters by the integrated control system is necessary and more effective to realize a desired vehicle motion than the summation of controls obtained by individually optimized systems.
14 citations
[...]
TL;DR: In this paper, a concave toothed surface of a conical conical gear is selected by considering a group of generating lines of an involute helicoid and a set of curved lines.
Abstract: PURPOSE:To increase the strength of the toothed surface of a concave conical gear by providing a concave conical gear where a concave toothed surface is selected. CONSTITUTION:Considering the normal toothed surface No of a conical gear, a group of generating lines ui (i=0, 1,...) of an involute helicoid and a group of curved lines vi (i=0, 1,...) serving as the loci of contact points on the toothed surface No exist on it while forming a network together. When the mounting positions of a pair of gears are decided, the loci of the contact points become only one curved line among the group of loci vi. So it is a curved line v0: ie. in the immediate neighborhood of the locus v0 of the contact point on toothed surfaces which mate with each other, the surface agrees with the involute helicoid which is the toothed surface of the conical gear, while in other parts such a concave face that may become a curved fact where the contact between the toothed surfaces approximates a line contact, ie. a concave toothed surface Co is selected.
13 citations
TL;DR: In this article, a palpation sensor for possible detection of prostatic cancer and hypertrophy was developed, which is a layered medium with two polyvinylidene fluoride (PVDF) films embedded in the matrix sponge rubber.
Abstract: This paper is concerned with the development of a palpation sensor for possible detection of prostatic cancer and hypertrophy. The sensor is a layered medium with two polyvinylidene fluoride (PVDF) films embedded in the matrix sponge rubber. This sensor fixed with a finger is pressed against the prostates and the output voltage signals from the polymer films are measured. The temporal mean values, I1 and I2, on the absolute signals from polymer films are calculated and their ratio I1/I2 is used as the sensor output. First, the experimental method for the clinical test is proposed. The prostate glands diagnosed by a doctor's fore finger are classified into four groups according to their stiffness and the data processing for assorting the glands into the groupes are presented. The effect of the convexes placed on the surface of sensor is examined by conparing the clinical data with that of the sensor without the convexes.
12 citations
TL;DR: In this article, a method of route selection for a vision-guided mobile robot with an odometry system when the map uncertainty is given is presented, where the robot first generates candidate routes, which are expanded to possible loci in consideration of the map uncertainties, then makes an observation and movement plan along each locus and computes the minimum traveling time.
Abstract: We present a method of route selection for a vision guided mobile robot with an odometry system when the map uncertainty is given. The robot first generates candidate routes, which are expanded to possible loci in consideration of the map uncertainty. It then makes an observation and movement plan along each locus and computes the minimum traveling time. Uncertainties of movement and visual sensing are considered in this step. Finally, for each candidate route, the robot computes its expected traveling time from the traveling times along the possible loci and their probabilities. It selects the route with the least expected traveling time as the optimal route. The advantage of the planning method is that the observation and movement planning is incorporated in path planning to obtain the optimal plan. The three sources of uncertainty are considered in a unified manner in our method. The method has been implemented and tested to validate our claim.
11 citations
TL;DR: Two new fault diagnosis systems are proposed which one diagnoses a fault based on behavior of the object system, and another diagnoses a faults based on power spectrum of theobject system.
Abstract: This research is concerned with the fault diagnosis for machines using neural networks. Generally, it is difficult to diagnose machine's fault by the conventional technique. In this research, two new fault diagnosis systems are proposed which one diagnoses a fault based on behavior of the object system, and another diagnoses a fault based on power spectrum of the object system. In the former, when an object system is a normal state, the system identification is performed by the neural networks. The diagnosis system detects a fault by finding the behavior's gap between the state of the real system and the identified normal one, and aIso the fault part is specified by fault diagnosis neural network. In the latter, neural network learns power spectrum of both the normal and fault states for the object. When a fault occurs, fault part is diagnosed by fault diagnosis neural network based on power spectrum. Finally, through simulation and experiment, the effectiveness of proposed fault diagnosis systems is verified.
11 citations
TL;DR: In this article, a laser ultrasonic system for a visualization of elastic waves propagating on a solid surface is presented. But this system can produce a series of successive images as an animation of wave propagation.
Abstract: We have developed a laser ultrasonic system for a visualization of elastic waves propagating on a solid surface. Scanning an optical heterodyne probe to measure surface transient displacements, ultrasonic waves in the frequency range up to 50 MHz are detected and passed to a personal computer through a digital oscilloscope. The recorded signals are reconstructed to make 3-D displacement images at any propagation time. This system can produce a series of successive images as an animation of wave propagation. Using this visualization technique, we observed the scattering and diffraction of ultrasonic waves around various shapes of penetrations on aluminum plate, and examined its application to nondestructive inspection.
TL;DR: In this paper, an impact model considering both duration of impact and energy loss is proposed, and the resulting force due to impact is formulated by introducing a complex stiffness coefficient in Hertz's contact theory.
Abstract: This paper deals with modeling and analysis of an impact system, which is composed of ball and plane. An impact model considering both duration of impact and energy ioss is proposed. The Resultant force due to impact is formulated by introducing a complex stiffness coefficient in Hertz's contact theory. From the expression for the resultant force, the impact system is modeled by both a nonlinear spring and a nonlinear dashpot. The characteristics of the nonlinear spring is expressed by using Hertz's theory, and that of the nonlinear dashpot is expressed by a function of the displacement and the velocity. The model parameters are determined by the configuration, the material value and the coefficient of restitution in the impact system. Experiment and simulation are carried out to demonstrate the accuracy of the proposed model, and good agreement is shown.
TL;DR: In this article, a 6 degrees of freedom parallel mechanism actuated by vertically fixed linear actuators was developed for heavy material handling and machining, which allows easy trajectory generation and simplifies the calculation of its inverse kinematics.
Abstract: A 6 degrees of freedom parallel mechanism actuated by vertically fixed linear actuators was developed for heavy material handling and machining. The mechanism allows easy trajectory generation, since the vertical arrangement of the linear actuators simplifies the calculation of its inverse kinematics. This paper presents inverse kinematics and jacobian matrix solutions. Ways to avoid component interference, which is divided into three types, are proposed. The combination of design parameters is decided by comparing the characteristics of area of movement, resolution and velocity. The working space is then shown. The singularity is analyzed by evaluating determinants of the jacobian matrix. Lengthening the connecting rods and limiting the range of the end-effector rotational angles are effective in avoiding the singular configurations as well as interference. Finally, the developed prototype mechanism is introduced, and its application to tool positioning and machining described.
TL;DR: In this article, a control method for the positioning of the flexible inverted pendulum and cart system is presented, which enables not only to eliminate the spillover phenomenon caused by the residual elastic modes but also to compensate the friction of the cart.
Abstract: This paper presents a control method for the positioning of the flexible inverted pendulum and cart system. The distributed parameter model is derived in considering the elasticity of the pendulum. The frequency dependent optimal servo system is designed using the reduced order model, which is derived by eliminating the dynamics of flexible modes. The proposed design method enables not only to eliminate the spillover phenomenon caused by the residual elastic modes but to compensate the friction of the cart. Some experimental results show the effectiveness of the proposed control system.
TL;DR: In this article, a rotational positioning mechanism with a harmonic speed reducer and a disturbance observer is described, which can be represented by two kinds of models, that is macrodynamic and microdynamic models.
Abstract: This paper describes the dynamic characteristics of the mechanism with a harmonic speed reducer and its precision rotational positioning. The harmonic speed reducer is the reduction gear which is often used for precision robots because they can be made very compact and lightweight without backlash. However they have the friction and the low stiffness which make the positioning performance low. The purpose of this research is to clarify the suitable control method for the rotational positioning mechanism with the gearing and to realize high speed and high precision rotational positioning over a wide range. For this purpose, first, the characteristics of the mechanism are examined experimentally. The experimental results show that the mechanism can be represented by two kinds of models, that is macrodynamic and microdynamic models. Then, by using the controller including disturbance observer, the mechanism has the positioning accuracy better than 1" on the working range more than 4.0×105".
TL;DR: In this article, a piezoelectric actuator for oscillating the bellows and two check valves were used to obtain a maximum flow rate of 80 mm3/s, maximum pumping pressure of 0.32 MPa and maximum power of 8.7 mW at the driving frequency of 2.0 kHz.
Abstract: As a power source for practical micromachines such as in-pipe mobile micromachines using fluid power, micropumps having high power density are required. In this paper, a piezoelectric micropump using resonance drive is proposed and developed. It basically consists of a bellows as a flexible pump chamber with an additional mass, a piezoelectric actuator for oscillating the bellows and cantilever type of two check valves. Firs fly, an effectiveness of the proposed micropump is confirmed through a fabrication of the large model and basic experiments. Secondly, a micropump with the size of φ9x10 mm for practical application is fabricated. Next, frequency characteristics and load characteristics of pressure-dependent flow rate are experimentally investigated with various structural parameters for optimal design. Through those experiments, the optimal amounts of additional mass and valve thickness are experimentally obtained for stable and high performance of the micropump. The maximum flow rate of 80 mm3/s, maximum pumping pressure of 0.32 MPa and maximum power of 8.7 mW are obtained at the driving frequency of 2.0 kHz. Also the feasibility of the piezoelectric micropump using resonance drive is confirmed through a comparison with conventional micropumps on maximum power density.
TL;DR: A synthetic method for the virtual face image based on the analysis of facial color in emotional change is proposed and seven enhanced facial color images are synthesized based on an average facial color image from 68 females.
Abstract: Human facil color can be applied to the display of virtual face image, emotional evaluation, individual identification, and remote health care. We already developed a method for emphasizing the individual characteristics in facial color based on a virtual face image using the HSV (hue, saturation, value) color space. To make virtual face images more natural and richer, the clarification of the relation between facial color and emotion would be expected. In this paper, we propose a synthetic method for the virtual face image based on the analysis of facial color in emotional change. First, the facial colors under the emotion of joy or anger are determined quantitatively by using the HSV color space. Secondly, we examined the relation between the facial color and the physiological index of facial skin temperature, which indicates the change of blood flux, in drinking for the emotion of joy. Also, we examined the relation between the change of facial color and that of skin temperature under the joy in laughing. Finally, on the basis of these results, we synthesized seven enhanced facial color images based on an average facial color image from 68 females, and evaluated the effectiveness of these images through sensory evaluation by paired comparison.
TL;DR: This paper focuses on a mobile robotic system with fuzzy controller, and proposes a sensory network as perception ability for the mobile robot, and discusses the effectiveness of the proposed method through computer simulation result of collision avoidance problems for theMobile robot.
Abstract: This paper deals with adaptation, evaluation, and learning for fuzzy based intelligent robotic system. The intelligence of a robot depends on the structure of hardware and software for processing information, that is, the structure determines the potentiality of intelligence. Based on perceptual information, a robot with structured intelligent makes action from four levels in parallel. In addition, the robot generates its motion through the interaction with environment, and at the same time, gradually acquires its skill based on the generated motion. In this paper, We focus on a mobile robotic system with fuzzy controller, and propose a sensory network as perception ability for the mobile robot. We discuss the effectiveness of the proposed method through computer simulation result of collision avoidance problems for the mobile robot.
TL;DR: In this paper, the authors examined the ability of the vehicle equipped with a sensor steering mechanism by utilizing a simulated trajectory in comparison to experimental results and derived the Dynamical equations of the four-wheeled vehicle with front and all wheel steering.
Abstract: This paper examines the ability of the vehicle equipped with sensor steering mechanism (SSM) by utilizing a simulated trajectory in comparison to experimental results. Dynamical equations of the four-wheeled vehicle with front and all wheel steering are derived. The program developed the trajectory of the vehicle moving on the flat oval surface in order to conform these maneuvers. This experiment tests the vehicle's capacity to automatically following in guide way alignment. Numerical and experimental results show the effectiveness of SSM in programing these maneuvers.
TL;DR: In this article, a soft tactile sensor made of a PVDF (Polyvinylidene Fluoride) film patch and rubber layers is assembled and slid over the same sample fabrics to collect the surface tactile information on the fabrics.
Abstract: This paper is a study on the valuation and mathematical formulation of human touch sensation. First, the feelings of touch are collected on five natural and chemical fabrics through the SD (Semantic Differential) method questionnaires sent to twenty three examinees. The feelings are valued on each fabric by using the weigthed mean on graded factor feelings. The multiple regression analysis is then introduced to represent the overall evaluation of touch on every fabric by a linear function of the valuations on feelings of touch. Next, a soft tactile sensor made of a PVDF (Polyvinylidene Fluoride) film patch and rubber layers is assembled and slid over the same sample fabrics to collect the surface tactile information on the fabrics. The features on the collected data are then extracted by calculating the temporal average of absolute out signal and using the intensity of power spectral density on the medium frequency range. Comparison of the results show that the PVDF sensor well describes the tactile perception of forefingers.
TL;DR: In this paper, a new hyperplane design for sliding mode control using a linear parameter varying (LPV) plant model of active magnetic bearing system with gyroscopic rotor was presented.
Abstract: This paper presents a new hyperplane design for sliding mode control using a linear parameter varying (LPV) plant model of active magnetic bearing system with gyroscopic rotor. We first extended the formulation of frequency shaped hyperplane design approach for LPV plants. Then, an actual turbomolecular pump system which has a overhung rotor contruction with gyroscopic effect is modeled as an LPV plant. The VSS control structure is derived for a single parameter dependent case using LPV plant model of the AMB system. The designed hyperplane for sliding mode control has a time varying structure with parameter variation. We carried out experiment using an actual AMB system and obtained good results.
TL;DR: In this paper, the authors proposed a new formulation which uses rigid-body modes and a local observer frame to express large amplitude rigid body motion and uses elastic modes to express small amplitude elastic vibration.
Abstract: This paper deals with dynamics of moving flexible bodies. The formulations proposed so far usually use Cartesian coordinates for the position of a body, Euler angles or Euler parameters for the orientations, and deformation modal coordinates for the elastic degrees of freedom. The equations of motion with these coordinates are complicated because of coupling terms between rigid-body motion and elastic vibration. In this paper, we propose a new formulation which uses rigid-body modes and a local observer frame to express large amplitude rigid-body motion and uses elastic modes to express small amplitude elastic vibration. The new formulation simplifies the coupling terms and gives the uniform description of equation in each modal coordinate, thus enables to accommodate the gross motion dynamics and the small amplitude elastodynamics effectively.
TL;DR: In this paper, transient dynamic response of the human finger skin and strain energy distribution at the tactile receptors are calculated when the finger is in contact with sinusoidal wave representing the surface roughness of objects.
Abstract: Contact condition between a cross section of a finger and a plane plate was analyzed in our previous study In this study, transient dynamic response of the human finger skin and strain energy distribution at the tactile receptors are calculated when the finger is in contact with sinusoidal wave representing the surface roughness of objects Especially, the effect of epidermal ridges, velocity of the finger movement and wavelength of the sinusoidal wave on the tactile sensation are focused FE (finite element) model using measured geometric and material properties of an actual index finger is used The contact between the finger with/without the epidermal ridges and the sinusoidal wave moved in the tangential direction after indented in the normal direction is calculated It is found that Meissner's corpuscles are largely in relation with the detection of surface roughness, Merkel's discs do not detect the surface roughness when the wavelength is small It is also found that the epidermal ridges change the pattern of strain energy density near the Meissner's corpuscles
TL;DR: In this article, the authors put forward a new approach by which function and efficiency of the product can be expressed in model before its structure is designed, and proposed the concept of functional model.
Abstract: The authors put forward a new approach by which function and efficiency of the product can be expressed in model before its structure is designed, and proposed the concept of functional model. In this report, this approach is applied to various kinds of planetary gear trains, and their functional models are presented. The planetary gear trains are used broadly in many kinds of machines, but it was difficult to model them by the conventional modeling approaches. A transmission gearing and a differential gearing are modeled as application examples, and simulations are carried out. It is clarified that the proposed functional model is a general model that can be applied widely to the product development of machines in which various kinds of the planetary gear trains are used.
TL;DR: In this paper, the identification method of automobile response to steering input using "normalized cornering stiffness", which represents both vehicle response and axle property, was discussed, and the measurement result about over twenty vehicles was shown.
Abstract: This paper discusses the identification method of automobile response to steering input using "normalized cornering stiffness", which is equivalent cornering stiffness divided by normal load and represents both vehicle response and axle property. Thus we can determine suspension, tire and steering system property to satisfy target response using normalized cornering stiffness. Firstly, this paper proposes the measurement method of normalized cornering stiffness using critical speed at which the vehicle attitude angle equals zero. This method features high accuracy because it is independent of the error of speed sensor. Next, the measurement result about over twenty vehicles is shown. This result points out that the variance of rear normalized cornering stiffness is quite large.